A powder metal steel alloy composition for high wear and temperature applications is made by water atomizing a molten steel alloy composition containing C in an amount of at least 3.0 wt %; at least one carbide-forming alloy element selected from the group consisting of: Cr, V, Mo or W; an O content less than about 0.5 wt %, and the balance comprising essentially Fe apart from incidental impurities. The high carbon content reduces the solubility of oxygen in the melt and thus lowers the oxygen content to a level below which would cause the carbide-forming element(s) to oxidixe during water atomization. The alloy elements are thus not tied up as oxides and are available to rapidly and readily form carbides in a subsequent sintering stage. The carbon, present in excess, is also available for diffusing into one or more other admixed powders that may be added to the prealloyed powder during sintering to control microstructure and properties of the final part.

High hardness prealloyed steel powder, such as tool steel grade of powders, can either be used alone or admixed with other powder metal compositions in the powder-metallurgy production of various articles of manufacture. Tool steels contain elements such as chromium, vanadium, molybdenum and tungsten which combine with carbon to form various carbides such as M6C, MC, M3C, M7C3, M23C6. These carbides are very hard and contribute to the wear resistance of tool steels.
The use of powder metal processing permits particles to be formed from fully alloyed molten metal, such that each particle possesses the fully alloyed chemical composition of the molten batch of metal. The powder metal process also permits rapid solidification of the molten metal into the small particles which eliminates macro segregation normally associated with ingot casting. In the case of highly alloyed steels, such as tool steel, a uniform distribution of carbides can be developed within each particle, making for a very hard and wear resistant powder material.
It is common to create the powder through atomization. In the case of tool steels and other alloys containing high levels of chromium, vanadium and/or molybdenum which are highly prone to oxidation, gas atomization is often used, wherein a stream of the molten alloy is poured through a nozzle into a protective chamber and impacted by a flow of high-pressure inert gas such as nitrogen which disperses the molten metal stream into droplets. The inert gas protects the alloying elements from oxidizing during atomization and the gas-atomized powder has a characteristic smooth, rounded shape.
Water atomization is also commonly used to produce powder metal. It is similar to gas atomization, except that high-pressure water is used in place of nitrogen gas as the atomizing fluid. Water can be a more effective quenching medium, so that the solidification rates can be higher as compared to conventional gas atomization. Water-atomized particles typically have a more irregular shape which can be more desirable during subsequent compaction of the powder to achieve a greater green strength of powder metal compacts. However, in the case of tool steels and other steels containing high levels of chromium, vanadium and/or molybdenum, the use of water as the atomizing fluid would cause the alloying elements to oxidize during atomization and tie these alloying elements up making them unavailable for reaction with carbon to form carbides. Consequently, if water atomization were employed, it may need to be followed up by a separate oxide reduction and/or annealing cycle, where the powder is heated and held at an elevated temperature for a lengthy period of time (on the order of several hours or days) and in the presence of a reducing agent such as powdered graphite, or other source of carbon or other reducing agent or by another reducing process. The carbon of the graphite would combine with the oxygen to free up the alloying elements so that they would be available for carbide formation during the subsequent sintering and tempering stages following consolidation of the powder into green compacts. It will be appreciated that the requirement for the extra annealing/reducing step and the addition of graphite powder adds cost and complexity to the formation of high alloy powders via the water atomization process.

Powdered metal alloy composition for wear and temperature resistance applications and method of producing same


A reflector for a lighting fixture that provides a uniform level of lighting. The reflector has a first arcuate portion having a first upper surface and a second arcuate portion having a second upper surface. A first aperture in the first arcuate portion is adapted to receive a first lamp. A second aperture in the second arcuate portion is adapted to receive a second lamp. First and second mounting members on the first and second upper surfaces are adapted to be connected to a lighting fixture housing.

Emergency lighting fixtures are frequently positioned near emergency exits to light emergency egresses from the area, and are commonly used in commercial buildings, residences, and the like. In addition to marking the location of the emergency exit, light emitted from the emergency lighting fixture illuminates the floor in the area of the emergency exit to clearly light the path to the exit.
One problem with existing emergency lighting fixtures is that the egress path is not clearly and uniformly illuminated in the area of the emergency exit. The reflectors in the emergency lighting fixture typically are not configured to clearly and uniformly illuminate the emergency egress. Light is emitted that is not directed to illuminating the emergency egress, thereby wasting light and resulting in an inefficient emergency lighting fixture. A need exists for an emergency lighting fixture that has a reflector configured to clearly and uniformly illuminate the emergency egress.
Another problem with existing emergency lighting fixtures is that the emitted light cannot easily be focused as desired. Some light emitted from the lighting fixture is not directed to illuminating the emergency egress. Light emitted from an emergency lighting fixture that is not directed to illuminating the emergency egress is essentially wasted light because it does not serve the purpose of lighting the emergency egress. Those inefficient emergency lighting fixtures could better light the emergency egress if the lighting fixtures were adjustable to focus the emitted light. A need therefore also exists for an emergency lighting fixture that is adjustable to focus the emitted light.
Another problem with existing emergency lighting fixtures is that the emitted light cannot be aimed as desired. For example, aiming the light emitted from the emergency lighting fixture would allow the light on an installed emergency lighting fixture to be directed to suit any changes in the area in the vicinity of the emergency exit. Furthermore, emergency lighting fixtures that are not capable of being aimed are only best suited for certain environments. For example, some buildings have hallways of various widths. Without being able to adjust the lighting fixture, one type of lighting fixture will not adequately illuminate all of the various hallway widths. Thus, a large inventory of emergency lighting fixtures is required to adequately illuminate the various hallway widths found in a single building. A need therefore also exists for an emergency lighting fixture that is adjustable to aim the emitted light.
Examples of existing lighting fixtures and double-arcuate shaped reflectors are disclosed in the following U.S. Pat. No. 1,812,919 to Balder; U.S. Pat. No. 5,140,504 to Sato; U.S. Pat. No. 5,192,129 to Figueroa; and U.S. Pat. No. 5,249,110 to Russello et al.
A need thus exists for an improved reflector for a lighting fixture.

Adjustable double-arcuate reflector for an emergency lighting fixture


An apparatus for coupling two circuits having different supply voltages is described herein.

1. Field of the Invention
The present invention relates to electronic devices, and in particular, to circuits relating to different supply voltage levels.
2. Description of Related Art
With microprocessor designs, there often is a need to use separate power supplies for microprocessor input-output (I/O) circuits and microprocessor core circuits. In a microprocessor system power and thermal management techniques for the core require changing the power supply voltages during use. While core clock frequencies are scaled back when supply voltage is reduced to save power, the I/O circuitry operates at a fixed system clock frequency. It is difficult to meet system timing requirements if the I/O supply has to function at the lowest values supported by the core supply. Also, the microprocessor's I/O circuitry interfaces over one or more buses with other devices which may have I/O modules fabricated using older manufacturing processes. Hence, such I/O modules do not function well at the lowest supply settings for the microprocessor core.
Having separate power supplies for the core and I/O sections of the microprocessor requires the use of level shifters. Level shifters propagate signals between supply domains while maintaining full rail swings between supply and ground. Without full-rail output swings, a signal would be more sensitive to noise and a following stage logic gate could dissipate large amounts of power by passing DC current between supply and ground. Level shifters are used to address this issue. While level shifters have the desirable attribute of rail-to-rail output swings, they exhibit longer gate delays than standard CMOS logic and are prone to significant delay variation due to changes in process, temperature, and the two supply voltages.
In source-synchronous system interfaces between microprocessors and buses connected to other devices, it is necessary in the microprocessor to use level shifters for transitioning on-chip signals between different supply voltage domains (also simply referred to as supply domains) for the core and I/O circuits. Hence, this provides one example of where level shifters introduce extra timing skew, in this case between the rising and falling edges or transitions of the data signals and strobes (forwarded clock signals). For a source-synchronous bus, an important metric is the relative timing between data and strobe edges (signal transitions). When subject to variations, the data and strobe transitioning in the same direction track each other well. The worst case timing skew occurs when data and strobe are transitioning in opposite directions.
Referring to FIG. 1, there is illustrated a prior art converter circuit, which includes a single level shifter 10 in the data path extending between a core supply domain 12 and a I/O supply domain 14. The two domains 12 and 14 are separated by a dashed line 16. A master latch 18 and slave latch 20 receives a Data1 signal which, in response to a clock signal, is provided to the level shifter 10 as a Data2 signal. The level shifter 10 produces a Level Shifted Data signal as an output. With this topology, the variation in the timing of a single edge may be significant, but the difference in the timing of rising and falling signals shows even more variation.
Referring to FIG. 2, the Clock, Data2 and Level Shifted Data signals are shown for the converter circuit of FIG. 1. The Data2 signal, relative to the rising edge of the Clock signal, is delayed based upon the delay introduced by the master and slave latches 18 and 20. Thereafter, the Level Shifted Data signal is further delayed by the level shifter 10, but more importantly, the cross hatching in the Level Shifted Data signal represents the miss-match in rise and fall delays of the rising and falling edges of the Level Shifted Data signal. This timing skew is sometimes referred to as Tco skew.

Apparatus coupling two circuits having different supply voltage sources


A method and apparatus for controlling when a calibration cycle is started for a metrology tool. The method and apparatus exploits a correlation between a drift of a first parameter (e.g., film thickness measurement drift) and a drift of a second parameter (e.g., CD measurement drift). One embodiment of the method comprises measuring a film thickness on one or more reference substrates to determine when a drift component of these measurements exceeds a pre-determined range and thereafter calibrating the metrology tool when the drift component of the film thickness measurements exceeds the pre-determined range. Generally, the drift of the film thickness measurement will occur prior to substantial drift of the CD measurement occurring.

1. Field of the Invention
The present invention generally relates to semiconductor substrate processing systems. More specifically, the present invention relates to a method and apparatus for controlling the calibration cycle of a metrology tool.
2. Description of the Related Art
Ultra large scale integrated (ULSI) circuits may include more than one million micro-electronic devices (e.g., transistors, capacitors, interconnecting lines, and the like) that are formed on a substrate (e.g., a silicon (Si) wafer) and which cooperate to perform various functions within the device. Fabrication of the electronic devices includes processes in which one or more layers of a film stack of such a device are deposited or etched, thereby forming one or more structures of the device being fabricated.
During manufacturing processes, topographic dimensions of structures formed on the substrates are measured to verify that the substrate processing reactors are operating within desired ranges that facilitate high yield and productivity. One typical procedure comprises measuring the smallest widths of the structures, such as lines, columns, openings, spaces between the lines, and the like. Such widths are known as "critical dimensions", or CDs, and are generally the most difficult elements of a structure to fabricate and measure. In advanced ULSI circuits, the critical dimensions generally are deep sub-micron dimensions having a nominal value of less than about 0.18 microns.
Metrology tools for performing critical dimension (CD) measurements of topographic structures require periodic calibration to ensure the measurements remain accurate. Generally, metrology tools are calibrated based on a predetermined number of measurements performed since the most recent calibration or, alternatively, based on a time duration that has passed since a previous calibration. These methods of determining when the metrology tool should be calibrated are referred to as "timed" calibrations. Such a timed calibration does not assess actual performance of the metrology tool between calibration cycles such that inaccurate tool performance (e.g., invalid or inaccurate CD measurements) may occur before a calibration cycle is begun. Since CD measurements are used to control process parameters, processing a substrate based upon an incorrect CD measurement can destroy one or more substrates. Furthermore, such "timed" calibration may cause calibration of the tool when such calibration is unnecessary. Consequently, substrate processing throughput may be unnecessarily impacted.
Therefore, there is a need in the art for a method and apparatus for anticipating when a metrology tool requires calibration such that the use of a calibration cycle can be accurately controlled.

Method and apparatus for controlling a calibration cycle or a metrology tool


A condition monitoring system that determines a presence of change of water content in grease. The system provides a sensor electrode that is placed in the space where the grease is located. The electrode is suitably a plate with a surface area creating a capacitance C. This in combination with a resistor R, creates an RC circuit. The system senses the RC circuit. The dielectric constant of the monitored grease varies in dependence of the water content of the grease. A change of the dielectric constant will change RC, that is then sensed by the system. An analysis of a change of RC will determine if there is a presence of a change of the level of water content in the monitored grease.

Reliable operation of rotating mechanical systems is highly dependent on proper lubrication. The condition of a lubricant is very important, especially for systems designed to operate for long periods with little or no maintenance. The presence of contaminants such as water or particles can lead to wear and damage of moving parts of the system and even premature catastrophic failure of the entire mechanical system. A lubricant of a mechanical system may primarily be either oil or grease based. Monitoring the condition of oil in an oil lubricated system can be accomplished by circulating the oil past a sensor and may additionally be provided with filters for removing contaminants. However, closed systems such as bearings are generally filled with an appropriate grease. The grease is maintained within the bearing or bearing housing with seals. The seals also protect the grease from ingress of contaminants such as water and particles. Seals may break or leak such that water enters the bearing or bearing housing. Water ingress decreases the lubrication ability of the grease and also increases the chance of corrosion damage of the bearing elements. There is thus a desire to monitor grease of a closed mechanical system, especially in relation to its water content. It is not possible to circulate the grease past a sensor without extreme difficulty and expense. There seems to still be room for improvements in this area.

Method and system of condition monitoring


A mechanical AND element (U) serves for mutual locking of power switches (LS1, LS2, LS3). A carrier (T) serves as the stop for three flexible transmission members (S1, S2, S3) whose Bowden cables (S7, S8, S9) with parallel longitudinal axes act upon a coupling carriage (K). The Bowden cables (S7, S8) for the input signals (E1, E2) work in opposite directions and are engaged with the coupling carriage (K) at the outside and approximately in the center, respectively. The Bowden cable (S9) for the output signal (A) is connected to the other, outer, side of the coupling carriage (K).

German Patent No. 44 09 172 A1 describes a mechanical AND element in which Bowden cables are prestressed by springs with respect to a coupling carriage. The device described therein requires that the spring forces be adjusted accurately.
German Patent No. 36 11 020 A1 describes another AND element, similar to the AND element described above, in which flexible transmission members are designed as wire trip elements that transmit compressive forces. The coupling carriage is displaced by a wire trip element for a first input signal and also serves as a carrier of the wire trip element for the second input signal. In this way, a complete stroke occurs at the output of the AND element only when both input signals are present. This type of operation, however, requires that the wire trip element for the second input signal be carried displaceably. Furthermore, careful adjustment of all wire trip elements is required to ensure that the wire trip element for the output signal is properly actuated and therefore that the desired action takes place only with a full stroke of the two wire trip elements for the input signals. For this reason, with the AND element described therein, a stepped intermediate lever is provided between the coupling carriages and the wire trip element for the output signal to change the transmission ratio.

Mechanical AND-member for mutually locking power switches


Pharmaceutical compositions, methods of administration, and methods of treatment of cancer with new generation taxoids, of formulas (I) and (II), and derivatives thereof, are described:

The present invention relates to new taxoids possessing strong antitumor activities, the precursors of these antitumor taxoids, and pharmaceutical compositions thereof.
Taxol (paclitaxel), a complex diterpene, is currently considered the most exciting lead in cancer chemotherapy. Paclitaxel possesses high cytotoxicity and strong antitumor activity against different cancers which have not been effectively treated by existing antitumor drugs. For example, paclitaxel has been approved by FDA in late 1992 for the treatment of advanced ovarian cancer and for breast cancer in 1994. Paclitaxel is currently in phase II and III clinical trial for lung cancer and other cancers.
Although paclitaxel is an extremely important xe2x80x9cleadxe2x80x9d in cancer chemotherapy, it is common that better drugs can be derived from naturally occurring lead compounds. In fact, French researchers have discovered that a modification of the C-13 side chain of paclitaxel brought about a new anticancer agent which seems to have antitumor activity superior to paclitaxel with better bioavailability. This synthetic compound was named xe2x80x9cTaxotxc3xa8re (docetaxel)xe2x80x9d, which has t-butoxycarbonyl instead of benzoyl on the amino group of (2R,3S)-phenylisoserine moiety at the C-13 position and a hydroxyl group instead of acetoxy group at C-10. Docetaxel is currently in phase II and III clinical trials in United States, Europe, and Japan, has shown excellent activity, especially against breast and lung cancers.
A recent report on clinical trials of paclitaxel and docetaxel has disclosed that paclitaxel causes, e.g., nerve damage, muscle pain or disturbances in heart rhythm, whereas docetaxel provokes, e.g., mouth sores and a plunge in white blood cells. Other less serious side effects also exist for these two drugs. Therefore, it is very important to develop new anti-cancer drugs different from these two drugs which have fewer undesirable side effects, better pharmacological properties, improved activity against drug-resistant tumors, and/or activity spectra against various tumor types.
It is an objective of the present invention to develop such new anti-tumor agents of paclitaxel class, i.e., taxoids, which have distinct structural differences from those of paclitaxel and docetaxel.
It is an object of the present invention to provide a series of new taxoids bearing a 1-propenyl, 2-methyl-1-propenyl, 2-methylpropyl, or trifluromethyl radical at the C-3xe2x80x2 position instead of a phenyl group, and which possess strong antitumor activities with better therapeutic profile, in particular against drug-resistant tumors. One of the serious drawbacks of both paclitaxel and docetaxel is the fact that these two drugs possess only a weak activity against drug-resistant tumors, e.g., adriamycin-resistant breast cancer. The new taxoids of the present invention have shown not only stronger antitumor activities against human ovarian, non-small cell lung, colon, and breast cancers than those of the two drugs, but also exhibit more than one order of magnitude better activity against adriamycin-resistant human breast cancer cells than those of the two drugs. Multi-drug-resistance (MDR) is a serious issue in clinical oncology, and thus the new taxoid antitumor agents of this invention will serve as important drugs to overcome this problem.
One aspect of the invention is a taxoid of the formula (I)
in which
R1 is a C3-C5 alkyl or alkenyl or trifluoromethyl radical;
R2 is a C3-C5 branched alkyl radical;
R3 and R4 are independently selected from hydrogen and hydroxyl protecting groups including functional groups which increase the water solubility of the taxoid antitumor agent;
R5 represents a hydrogen or hydroxyl-protecting an acyl or alkoxycarbonyl or carbamoyl group;
R6 represents an acyl radical,
which are useful as antitumor agents or their precursors.
Preferably, R1 is selected from propyl, 2-methyl-1-propenyl, 1-methyl-1-propenyl, 2-methylpropyl, 1-methylpropyl, tert-butyl, cyclopropyl, cyclopropylmethyl, 1-methyl-1-butenyl, 2-methyl-1-butenyl, 3-methyl-1-butenyl, 1-methylbutyl, 2-methylbutyl, isobutyl, 2-methylethyl, 3-methylbutyl, 2-butenyl, or trifluoromethyl radicals;
R2 is selected from isopropyl, cyclopropyl, isobutyl, sec-butyl, 2-methylpropyl, 3-methylpropyl, tert-butyl, cyclobutyl, cyclopentyl, 1-ethylpropyl, or 1,1-dimethylpropyl radicals;
R5 is selected from hydrogen, C2-C6 acyl, C1-C6 alkoxylcarbonyl, C1-C6 N-alkylcarbamoyl, or C1-C6 N,N-dialkylcarbamoyl radicals; and
R6 is selected from benzoyl, fluorobenzoyl, chlorobenzoyl, azidobenzoyl, cyclohexanecarbonyl, acryloyl, crotonoyl, 1-methylacryloyl, 2-methyl-2-butenoyl, or 3-methyl-3-butenoyl radical.
More preferably, R5 is selected from acetyl, propanoyl, cyclopropanecarbonyl, acryloyl, crotonoyl, 3,3-dimethylacryloyl, N-methylcarbamoyl, N-ethylcarbamoyl, N,N-dimethylcarbamoyl, N,N-diethylcarbamoyl, pyrrolidine-N-carbonyl, piperidine-N-carbonyl, morpholine-N-carbonyl, methoxycarbonyl, ethoxylcarbonyl, propoxylcarbonyl, butoxycarbonyl, cyclopentanecarbonyl, or cyclohexanecarbonyl radicals.
These new taxoids (I) are synthesized by the processes which comprise the coupling reactions of the baccatin of the formula (II)
wherein G1 represents a hydroxyl protecting group, and R5 and R6 have been defined above, with the xcex2-lactams of the formula (III)
wherein G is a hydroxyl protecting group such as ethoxyethyl (EE), triethylsilyl (TES), (tert-butyl)dimethylsilyl (TBS), and triisopropylsilyl (TIPS), and R1 and R2 have been defined above, in the presence of a base.
Another aspect of the invention is a taxoid of the formula (7):
wherein
R1 is a branched or unbranched C3-C5 alkyl or alkenyl radical, CF2H, or (S)-2,2-dimethylcyclopropyl; R8 is a C1-C4 alkyl radical; and R7 is F, Cl, MeO, vinyl, Me, or N3.
R1 is preferably a branched or unbranched C4 alkyl or alkenyl radical, more preferably CH2CH(CH3)2 or CHxe2x95x90C(CH3)2. R7 is preferably MeO or N3.
In one embodiment, R1 is CH2CH(CH3)2, R7 is MeO, and R8 is ethyl. In another embodiment, R1 is CHxe2x95x90C(CH3)2, R7 is MeO, and R8 is ethyl. In yet another embodiment, R1 is CHxe2x95x90C(CH3)2, R7 is N3, and R8 is ethyl.
The invention also encompasses a method for treating tumors which comprises administering to a patient an effective amount of the taxoid of formula (7). Preferably, the method treats leukemia, melanoma, breast, non-small cell lung, ovarian, and colon cancers.
Yet another aspect of the invention is a pharmaceutical composition having antineoplastic activity containing the taxoid of formula (7) and a physiologically acceptable carrier.
A further aspect of the invention is a method for preparing a taxoid of formula (7), including coupling a baccatin of formula (5) with a xcex2-lactam of formula (6) in the presence of a base,
wherein G and G1, which may be the same or different, each represents a hydroxyl protecting group, and R1, R7, and R8 are as defined for formula (7). Preferably, G and G1 are independently ethoxyethyl (EE), triethylsilyl (TES), (tert-butyl)dimethylsilyl (TBS), or triisopropylsityl (TIPS).
New taxoids of the formula (I) hereinabove are useful as antitumor agents or their precursors. These taxoids possess strong antitumor activities against human breast, non-small cell lung, ovarian, and colon cancers including drug-resistant cancer cells, as well as leukemia and melanoma.
The new taxoids of the formula (I) are synthesized by modifying the baccatins of the formula (II)
wherein G1, R5, and R6 have been defined above.
The baccatins (II) are coupled with the xcex2-lactams of the formula (III)
wherein G, R1 , and R2have been defined hereinabove, to yield the new taxoids (I) .
The xcex2-lactams (III) are readily prepared via the xcex2-lactams (IV) which are easily obtained through the chiral enolate-imine cyclocondensation method that has been developed in the present inventor""s laboratory as shown in Scheme I (Ojima et al., Bioorg. Med. Chem. Lett., 1993, 3, 2479, Ojima et al., Tetrahedron Lett., 1993, 34, 4149, Ojima et al., Tetrahedron Lett. 1992, 33, 5739, Ojima et al., Tetrahedron, 1992, 48, 6985, Ojima, I. et al., J. Org. Chem., 1991, 56, 1681, the disclosures of which are incorporated herein by reference). In this preparation, the xcex2-lactams (IV) with extremely high enantiomeric purities are obtained in high yields. In Scheme 1, R* is a chiral auxiliary moiety which is (xe2x88x92)-trans-2-phenyl-1-cyclohexyl or (xe2x88x92)-10-dicyclohexylsulfamoyl-D-isobornyl, TMS is a trimethylsilyl radical, and the base is lithium diisopropylamide or lithium hexamethyldisilazide and G and R1 have been defined hereinabove.
The xcex2-lactams (IV) can be converted to the corresponding N-alkoxycarbonyl-xcex2-lactams (III) in excellent yields by reacting with alkyl chloroformates in the presence of a base (Scheme 2). This transformation is known to those skilled in the art.
The xcex2-lactams (III) are readily used for coupling with the baccatins (II) in the presence of a base, followed by deprotection to give the new taxoids (I) in high yields (Scheme 3).
In Schemes 1-3, R1 through R6 have been defined above, M is an alkali metal, and the hydroxyl protecting group G1 is independently selected from methoxylmethyl (MOM), methoxyethyl (MEM), 1-ethoxyethyl (EE), benzyloxymethyl, (xcex2-trimethylsilylethoxyl)-methyl, tetrahydropyranyl, 2,2,2-trichloroethoxylcarbonyl (Troc), benzyloxycarbonyl (CBZ), tert-butoxycarbonyl (t-BOC), 9-fluorenylmethoxycarbonyl (Fmoc), 2,2,2-trichloroethoxymethyl, trimethylsilyl, triethylsilyl, tripropylsilyl, dimethylethylsilyl, dimethyl(t-butyl)silyl, diethylmethylsilyl, dimethylphenylsilyl, diphenylmethylsilyl, acetyl, chloroacetyl, dichloroacetyl, trichloroacetyl and trifluoroacetyl.
The coupling reaction of the baccatin (II) and the xcex2-lactams (VI) is carried out via an alkali metal alkoxide of the baccatin (II) at the C-13 hydroxyl group. The alkoxide can readily be generated by reacting the baccatin with an alkali metal base such as sodium hexamethyldisilazide, potassium hexamethyldisilazide, lithium hexamethyldisilazide, sodium diisopropylamide, potassium diisopropylamide, lithium diisopropylamide, sodium hydride, in a dry nonprotic organic solvent such as tetrahydrofuran (THF), dioxane, ether, dimethoxyethane (DME), diglyme, dimethylformamide (DMF), mixtures of these solvents with hexane, toluene, and xylene, in a preferred temperature range from about xe2x88x92100xc2x0 C. to about 50xc2x0 C., more preferably at about xe2x88x9278xc2x0 C. to about 25xc2x0 C. This reaction is preferably carried out under inert atmosphere such as nitrogen and argon. The amount of the base used for the reaction is preferably approximately equivalent to the amount of the baccatin when soluble bases such as sodium hexamethyldisilazide, potassium hexamethyldisilazide, lithium hexamethyldisilazide, sodium diisopropylamide, potassium diisopropylamide, lithium diisopropylamide are used. The use of a slight excess of the base does not adversely affect the reaction. When heterogeneous bases such as sodium hydride and potassium hydride are used, 5-10 equivalents of the base (to the amount of the baccatin) are preferably employed.
The coupling reaction of the metal alkoxide of the baccatin thus generated with the xcex2-lactam is typically carried out by adding the solution of the xcex2-lactam in a dry organic solvent exemplified above in a preferred temperature range from about xe2x88x92100xc2x0 C. to 50xc2x0 C., more preferably at about xe2x88x9235xc2x0 C. to 25xc2x0 C. The mixture of reactants is stirred for 15 minutes to 24 hours and the progress and the completion of the reaction is monitored by thin layer chromatography (TLC), for example. When the limiting reactant is completely consumed, the reaction is quenched by addition of a cold brine solution. The crude reaction mixture is worked up using the standard isolation procedures which are generally known to those skilled in the art to give the corresponding taxoid. The proportion of the xcex2-lactam and the baccatin is in a range from 2:1 to 1:2, more preferably approximately 1:1 for purposes of economy and efficiency, but the ratio is not critical for the reaction.
The hydroxyl protecting groups can then be removed by using the standard procedures which are generally known to those skilled in the art to give the desired taxoid derivatives. For example, EE and TES groups can be removed with 0.5N HCl at room temperature for 36 h, TIPS and TBS groups can be removed by treating with fluoride ion or HF in a non-protic organic solvent, and Troc group can be removed with zinc and acetic acid in methanol at 60xc2x0 C. for 1 hour without disturbing the other functional groups and the skeleton of the taxoid.
It has been shown that the introduction of 2-methyl-1-propenyl group to the C-3xe2x80x2 position of paclitaxel appears to increase the cytotoxicity, especially against drug-resistant cancer cells: Holton and Nadizadeh disclosed in U.S. Pat. No. 5,284,864 (1994) that 3xe2x80x2-dephenyl-3xe2x80x2-isobutenylpaclitaxel (RAH-1) exhibited 4 times better activity than paclitaxel and 7 times better activity than docetaxel against human colon carcinoma cells HCT-116, and also about 20 times better activity than paclitaxel and 9 times better activity than docetaxel against multi-drug resistant phenotype human colon carcinoma cells HCT-116/VM.
We have found that the structural requirements for taxoid antitumor agents to express strong potency are rather strict and unpredictable. For example, 3xe2x80x2-dephenyl-3xe2x80x2-(2-phenylethenyl)docetaxel, bearing 2-phenylethenyl group instead of the isobutenyl group of RAH-1, has dramatically decreased cytotoxicity ( greater than 20 times) and 3xe2x80x2-dephenyl-3xe2x80x2-neopentyldocetaxel, bearing neopentyl group which has just one more methyl than isobutenyl group, is virtually not cytotoxic against A121 human ovarian, A549 human non-small cell lung, HT-29 human colon and MCF7 human breast cancer cells. While looking at the structure-activity relationships (SAR) of new taxoids that have different substituents at the C-3xe2x80x2 and C-10, we discovered that there are optimum combinations of these two substituents which achieve extraordinarily high activity against drug-resistant cancer cells.
After searching for the best substituent for the C-3xe2x80x2 and the C-10 positions by employing many alkyl groups and alkenyl groups by trial and error, we have identified 1-propenyl, 2-methyl-1-propenyl, 2-methylpropyl, and trifluoromethyl groups to be the optimum substituents for the C-3xe2x80x2 position, and acyl groups, alkoxycarbonyl groups, and N,N-dialkylcarbamoyl groups to be the optimum substituents for the C-10 position.
For example, 3xe2x80x2-dephenyl-3xe2x80x2-(1-propenyl)-10-acetyldocetaxel (Taxoid Ia) showed a substantially better activity spectrum than that of paclitaxel and docetaxel against human ovaian, human non-small cell lung, human colon, and human breast cancer cells mentioned above (see TABLE 1 in EXAMPLE 32). Moreover, this agent possesses 21 times better activity than paclitaxel and 17 times better activity than docetaxel against the drug-resistant human breast cells MCF7-R, which are mammary carcinoma cells 180 fold resistant to a widely used anticancer drug, adriamycin. In the same assay, Holton""s compound RAH-1 showed only marginal activity that was one order of magnitude weaker than that of Taxoid Ia (see TABLE 1 in EXAMPLE 32).
3xe2x80x2-Dephenyl-3xe2x80x2-(2-methyl-1-propenyl)-10-cyclopropanecarbonyldocetaxel (Taxoid IX) showed one order of magnitude better activity than that of paclitaxel and docetaxel against human human breast cancer cells mentioned above (see TABLE 2 in Example 32), and possesses two order of magnitude (142 times) better activity against the drug-resistant human breast cells mentioned above. These extraordinarily high activities are totally unpredictable from the existing SAR studies of paclitaxel and docetaxel, and thus demonstrate the exceptional importance of our discovery.
The taxoids of the formula (I) of this invention are useful for inhibiting tumor growth or regression of tumors in animals including humans and are preferably administered in the form of a pharmaceutical composition including effective amounts of the antitumor agent of this invention in combination with a pharmaceutically acceptable vehicle or diluent.
The pharmaceutical compositions of the antitumor agents of the present invention may be made in any form suitable for desired use, e.g., oral, parenteral or topical administration. Examples of parenteral administration are intramuscular, intravenous, intraperitoneal, rectal, and subcutaneous administration. The vehicle or diluent ingredients should not reduce the therapeutic effects of the antitumor agents of this invention.
Suitable dosage forms for oral use include tablets, dispersible powders, granules, capsules, suspension, syrups, and elixirs. Examples of inert diluents and vehicles for tablets include calcium carbonate, sodium carbonate, lactose and talc. Examples of inert diluents and vehicles for capsules include calcium carbonate, calcium phosphate, and kaolin. Dosage forms appropriate for parenteral administration include solutions, suspensions, dispersions, and emulsions.
The water solubility of the antitumor agents of the formula (I) may be improved by modifying the C-2xe2x80x2 and /or C-7 substituents to incorporate suitable functional groups, such as R3 and R4. In order to increase the water solubility, R3 and R4 can be independently selected from hydrogen and xe2x80x94COxe2x80x94Xxe2x80x94Y, wherein X is selected from xe2x80x94(CH2)nxe2x80x94 (n=1-3), xe2x80x94CHxe2x95x90CHxe2x80x94, cyclohexanediyl, and benzenediyl and Y is selected from xe2x80x94COOH and its pharmaceutically acceptable salts, xe2x80x94SO3H and its pharmaceutically acceptable salts, xe2x80x94NR7R8 and its pharmaceutically acceptable salts, the pharmaceutically acceptable ammonium salt xe2x80x94NR7R8R9, xe2x80x94CONR8R9, or xe2x80x94COOR9, in which
xe2x80x94NR7R8 includes cyclic amine radicals selected from pyrrolidinyl, piperidinyl, morphorino, piperazinyl, and N-methylpiperazinyl;
R7 and R8 are independently selected from hydrogen, allyl, C1-C6 alkyl, and xe2x80x94(CH2)nxe2x80x94Z (n=1-3);
R9 is selected from C1-C6 alkyl, allyl, and xe2x80x94(CH2)nxe2x80x94Z (n=1-3), and
Z is selected from xe2x80x94COOH and its pharmaceutically acceptable salts, xe2x80x94SO3H and its pharmaceutically acceptable salts, xe2x80x94NR7R8 and its pharmaceutically acceptable salts, and pharmaceutically acceptable ammonium salt xe2x80x94NR7R8R10, in which R10 is selected from hydrogen, allyl, and C1-C6 alkyl.
The preparation of the water-soluble analogs of paclitaxel bearing the functionalized acyl groups described above has been disclosed in Kingston et al., U.S. Pat. No. 5,059,699 (1991); Stella et al., U.S. Pat. No. 4,960,790 (1990), the disclosures of which are incorporated herein by reference, and thus it is not difficult for the people in the art to carry out such modifications.
The following non-limiting examples are illustrative of the present invention. It should be noted that various changes could be made in the examples and processes therein without departing from the scope of the present invention. For this reason, it is intended that the embodiments of the present application should be interpreted as being illustrative and not limiting in any sense.

Taxoid anti-tumor agents and pharmaceutical compositions thereof

The Research Foundation of the state University of New York


A photoconductor containing a supporting substrate, a photogenerating layer; and at least one charge transport layer where the photogenerating layer contains a photogenerating pigment and a chelating additive or agent of, for example, a β-diketone, a ketoester, a hydroxyl carboxylic acid, a hydroxyl carboxylic acid ester, a keto alcohol, or an amino alcohol.

This disclosure is generally directed to imaging members, photoreceptors, photoconductors, and the like. More specifically, the present disclosure is directed to rigid or multilayered flexible, belt imaging members, or devices comprised of an optional supporting medium like a substrate, an optional undercoat or hole blocking layer usually situated between the substrate and the photogenerating layer, a chelating component or agent which primarily functions to passivate the impurities, such as metallic materials present in the photogenerating pigment and/or photogenerating pigment dispersion to, for example, achieve acceptable, that is minimal, charge deficient spots (CDS), and at least one charge transport layer, wherein at least one is from 1 to about 5, from 1 to about 3, 2, one, and the like, such as a first charge transport layer and a second charge transport layer, an optional adhesive layer, and an optional overcoating layer, and wherein at least one of the charge transport layers contains at least one charge transport component, and a polymer or resin binder, and where in embodiments the resin binder selected for the undercoat layer is a known suitable binder including a binder that is substantially insoluble in a number of solvents like methylene chloride, examples of these binders being illustrated in copending application Ser. No. 11/593,658, filed Nov. 7, 2006, the disclosure of which is totally incorporated herein by reference. In embodiments, there is disclosed a photoconductor where the photogenerating dispersion contains a chelating agent, which for example, captures impurities, such as metallic substances, that are present in the selected photogenerating pigment as obtained or that are formed, such as by attritor milling, during the preparation of the photogenerating pigment layer solution.
In embodiments there are disclosed low charge deficient spots (CDS) photoconductors where the photogenerating pigment impurities are passivated by chelating agents or a chelating agent. Also, when present the hole blocking layer can contain in embodiments phenol resins, known hole blocking layer polymers as illustrated in U.S. Pat. No. 6,913,863, the disclosure of which is totally incorporated herein by reference, which discloses a hole blocking layer, a photogenerating layer, and a charge transport layer, and wherein the hole blocking layer is comprised of a metal oxide; and a mixture of a phenolic compound and a phenolic resin wherein the phenolic compound contains at least two phenolic groups, or chlorinated polymeric resins as the binder and a hydrolyzed aminosilane as the electroconducting species since it is believed that the CH2Cl2 insoluble binders prevent or minimize the migration of hole transport molecules from upper charge transport layer into lower layers, and then into the undercoat or ground plane layer. Examples of chlorinated homopolymers include polyvinylidene chloride, chlorinated polyvinyl chloride, and chlorinated polyvinylidene chloride. Examples of chlorinated copolymers include copolymers of vinylidene chloride, chlorinated vinyl chloride, and chlorinated vinylidene chloride with vinylidene fluoride, tetrafluoroethylene, trifluorochloroethylene, hexafluoropropylene, and the like.
A number of advantages are associated with the disclosed photoconductors, such as for example the formation of minimal charge deficient spots (CDS) which result in undesirable printing defects, and where the spots can be generated from the photogenerating layer, and the charge transport layer or layers; minimization or prevention of the migration of hole transport molecules or components from one charge transport layer to another layer in the photoconductor, such as the photogenerating layer and the charge transport layer, and more specifically, from the top or upper charge transport layer into lower layers of the photoconductor, such as lower charge transport layers, and the lower photogenerating layer thereby permitting less undesirable charge deficient spots in the developed image generated. The photoreceptors illustrated herein, in embodiments, have extended lifetimes; possess excellent, and in a number of instances low Vr (residual potential); and allow the substantial prevention of Vr cycle up when appropriate; high sensitivity; low acceptable image ghosting characteristics; and desirable toner cleanability.
Also included within the scope of the present disclosure are methods of imaging and printing with the photoconductors illustrated herein. These methods generally involve the formation of an electrostatic latent image on the imaging member, followed by developing the image with a toner composition comprised, for example, of thermoplastic resin, colorant, such as pigment, charge additive, and surface additive, reference U.S. Pat. Nos. 4,560,635; 4,298,697 and 4,338,390, the disclosures of which are totally incorporated herein by reference, subsequently transferring the image to a suitable substrate, and permanently affixing the image thereto. In those environments wherein the photoconductor is to be used in a printing mode, the imaging method involves the same operation with the exception that exposure can be accomplished with a laser device or image bar. More specifically, the flexible photoconductor belts disclosed herein can be selected for the Xerox Corporation iGEN® machines that generate with some versions over 100 copies per minute. Processes of imaging, especially xerographic imaging and printing, including digital, and/or color printing, are thus encompassed by the present disclosure.

Photoconductors containing photogenerating chelating components


Systems and methods for blackout management in media distribution systems may include a central data center in a service provider's domain. The central data server may coordinate with a blackout manager that implements control features for blackout. In contrast to (or to supplement) blackout control solutions that require integrated receiver decoders (IRD)s to be physically installed at each of the regional headends in the service provider network, the blackout manager may provide three functions: 1) a Virtual IRD (VIRD) function 2) access control functions via access control component, and 3) VIRD-to-EndPoint mapping function in the linkage manager.

Blackout management is desirable to control access to media content, and is typically used to prevent the delivery of certain media content to specific marketing areas. In many scenarios, blackout management is required as a result of a contractual agreement with the rights holders, such as a contractual agreement that commonly exists between a professional sports league, the rights holder, and the sports content broadcaster, the content programmer.
Existing solutions for blackout require the physical installation of integrated receiver decoder (IRD)s in the regional headends of the service provider's network. Content programmers provide media content to service providers and the service providers distribute the content to its subscribers via regional headends. Content programmers blackout access to media content by issuing commands that control designated integrated receiver decoder(s) (IRDs) in the regional headends that serve the blackout region.
It is inefficient and impractical for service providers to deploy IRDs in each of their regional headends to support blackout control. Consider a scenario in which fifteen different regions are supported by a respective fifteen regional headends. In each of the fifteen headends, physical IRDs have to be installed for each transport stream for each content programmer that requires blackout processing. So, in a single headend, often as many as one hundred IRDs have to be deployed (doubling that amount for redundancy) in each regional headend. For just fifteen regions, the number of IRDs to be installed in each regional headend becomes innumerous. Furthermore, to integrate the physical IRD in each headend, ancillary equipment is often needed at both the input of the IRD (to format the inputs to a format readable by the IRD) and at the output of the IRD (to multiplex the output streams).
The current infrastructure, therefore, requires significant power, shelf space, and network router ports sufficient to support all of the IRDs in each regional headend. Thus, the current solutions for blackout management are less than optimal and improved designs are desirable.


Provided is an apparatus and method for switching a navigation mode between a vehicle navigation mode and a personal navigation mode in a navigation device supporting vehicle navigation and personal navigation. Switching between the vehicle navigation mode and the personal navigation mode is performed according to whether the navigation device is mounted in a navigation device holder, whether a GPS speed provided by a GPS receiver is higher than a predetermined speed, and whether a step is detected using an output of an accelerometer. Since mode switching between the vehicle navigation mode and the personal navigation mode is automatically performed, a user does not need to manually perform mode switching.

1. Field of the Invention
The present invention relates generally to a navigation system supporting vehicle navigation and personal navigation, and in particular, to an apparatus and method for switching a navigation mode between a vehicle navigation mode and a personal navigation mode in a navigation device supporting vehicle navigation and personal navigation.
2. Description of the Related Art
Vehicle navigation systems, for example a car navigation system, recognizes a current position of a user's car. It provides an optimal route to a user's desired destination to the user, and guides the user along the optimal route. Generally, car navigation calculates the current position of the car using a Global Positioning System (GPS) sensor and a Dead Reckoning (DR) sensor and guides a route from the current position to the destination.
Personal navigation devices guide a route for a walker, and is similar to car navigation. But unlike car navigation, it requires more accurate position measurement and more detailed route guiding because the speed of the walker is generally slower than that of the car.
Thus, car navigation and personal navigation perform route guiding using different navigation algorithms. For example, car navigation recognizes a current position of a car by directly integrating outputs of an accelerometer sensor, whereas personal navigation detects steps of a walker to recognize a current position of the walker. For this reason, car navigation and personal navigation use separate dedicated navigation devices for performing different algorithms or are implemented to operate different algorithms separately even when using one navigation device.
The use of separate navigation devices for car navigation and personal navigation increases cost and causes inconvenience. To solve the problem, a navigation device supporting both car navigation and personal navigation has been recently developed.
However, in conventional navigation devices supporting car navigation and personal navigation, a user is required to manually perform mode switching between car navigation and personal navigation. In other words, the user manually terminates car navigation and initiates personal navigation to use personal navigation during the use of car navigation, and vice versa.
As a result, conventional navigation devices cause inconvenience because the user has to separately input car navigation information and personal navigation information. Moreover, when the user mistakenly switches to car navigation for personal navigation or vice versa, it may result in wrong route guiding.

Apparatus and method for switching navigation mode between vehicle navigation mode and personal navigation mode in navigation device


A microphone in which a core of an output transformer can be grounded without soldering and degradation of magnetic properties of the core can be prevented by preventing mechanical damage to the output transformer even if an impact force of the microphone is applied is obtained. A grounding pattern is formed in an output transformer mounting location of a circuit board incorporated in the microphone, a conductive fabric is put on the grounding pattern, a core of the output transformer is stacked and arranged on the conductive fabric, and the core of the output transformer is grounded through the conductive fabric. A second conductive fabric that covers the output transformer and is in contact with an inner circumferential surface of a microphone case may be provided and the microphone case may be grounded by bringing the second conductive fabric into contact with the core of the output transformer.

1. Field of the Invention
The present invention relates to a microphone and, more particularly, to a grounding structure of an output transformer thereof.
2. Related Background of the Invention
Since a signal level of signal output of a microphone is low, a balance signal is used for output. For a conversion into a balance signal output, an output transformer with a center tap is used in most cases. Since a smaller output transformer of a microphone is preferable if possible, high-permeability material is used as a core material. Examples of high-permeability material include a permalloy. A core board made of high-permeability material such as the permalloy is heat-treated so that magnetic properties are in best conditions, and then the core boards are stacked to produce a core and the core is wire-wound to assemble a transformer. Magnetic properties of the core of a transformer made of high-permeability material, typically permalloy, deteriorate when heated. Also, the core, if deformed or impacted, has a propensity that magnetic properties thereof deteriorate under an influence of an internal stress or the like.
If a core of an output transformer of a microphone is grounded while the output transformer is incorporated in the microphone, external noise can be made to escape to a ground and mixing of noise with a sound signal converted by the microphone can be prevented. It is true, however, that some low-priced microphones do not have a grounded core of an output transformer, and in such microphones, noise may be mixed with a sound signal under the influence of external noise.
An internal structure of a general microphone, particularly a structure of an output transformer portion will be described below with reference to FIGS. 3A to 3C and subsequent figures. In FIGS. 3A to 3C, the microphone has, roughly speaking, a microphone case 50, a microphone unit 10 incorporated in a front end (left end in FIGS. 3A to 3C) of the microphone case 50, a circuit board 30 disposed inside the microphone case 50, an output transformer 20 disposed adjacent to a rear end of the circuit board 30, and a connector 40 disposed by connecting to the rear end of the circuit board 30 in a rear end of the microphone case 50. A form of the microphone unit 10 is not specifically limited and the example shown is a condenser type microphone. The connector 40 is a standardized 3-pin type connector and has three pins 41.
The output transformer 20 is mounted on the circuit board 30 and an end of a primary coil and that of a secondary coil are electrically connected to a predetermined circuit pattern by soldering or the like. FIGS. 4A to 4C show an appearance of the output transformer 20, and FIG. 4A is a plan view, FIG. 4B is a front view, and FIG. 4C is a right side view. In FIG. 4A, FIG. 4B, and FIG. 4C, the output transformer 20 has a core 21 and a coil 22 wound around the core 21. The core 21 comprises, for example, a U-shaped core board and an I-shaped core board that is stacked on an open end of the U-shaped core board to connect the open end. By inverting an orientation of the open end of the U-shaped core board and a position of the I-shaped core board alternately, that is, by stacking while turning around by 180 degrees alternately on a plane parallel to a core surface, the core 21 is formed as a rectangular frame. The coil 22 consists of a primary coil and a secondary coil, and the output transformer 20 is constructed by winding each coil around a bobbin and assembling each bobbin in a way in which one bobbin is inserted into one side of the rectangular frame and the other bobbin into the opposite side. To make a signal output of the microphone a balance output, the secondary coil of the output transformer 20 is a coil with a center tap.
As described above, the core 21 of the output transformer 20 is grounded to avoid influences of external noise. The core 21 can be grounded by electrically connecting it to a grounding pattern of the circuit board 30. FIG. 5A, FIG. 5B, and FIG. 5C show an example thereof. This is an example in which a grounding pattern is formed on the circuit board 30 in a position opposite to and in contact with the core 21 of the output transformer 20 and the core 21 is soldered to the grounding pattern while the output transformer 20 is put on the circuit board 30 to fix the output transformer 20. In FIG. 5A, FIG. 5B, and FIG. 5C, reference numeral 26 denotes solder for the grounding.
However, like the example shown in FIG. 5A, FIG. 5B, and FIG. 5C, soldering of the core 21 of the output transformer 20 directly to the grounding pattern is not preferable. This is because heating of the core 21 during soldering causes a temperature to rise, leading to degradation of magnetic properties of the core 21.
Another conventional example in which the core 21 of the output transformer 20 is grounded is shown in FIG. 6. In this example, a thin metal plate 27 to which a lead wire 28 is soldered on one end thereof is used. The metal plate 27 is inserted between core boards constituting the core 21 of the output transformer 20 disposed and fixed at a predetermined position of the circuit board 30 so that electricity is conducted between the core 21 and the metal plate 27, and the lead wire 28 is soldered to a grounding pattern of the circuit board 30 to electrically connect the core 21 to the grounding pattern. Since, excluding this grounding structure, the structure is the same as that of the conventional example shown in FIG. 5A, FIG. 5B, and FIG. 5C, a description thereof is omitted.
Since, according to the conventional example shown in FIG. 6, the thin metal plate 27 is inserted between core boards, a stress (internal stress) is disadvantageously applied to the core boards constituting the core 21, leading to degradation of magnetic properties.
In still another conventional example of grounding the core 21 of the output transformer 20, the core 21 is tightened with a bare conductive wire when fixing the output transformer 20 to the circuit board 30 and the grounding occurs through the conductive wire. However, this grounding structure also has disadvantages that a stress is applied to the core boards by a tightening force of the conductive wire, and when an impact force is applied to a microphone, the impact force is also applied to the output transformer through the conductive wire to add mechanical damage, leading to change of magnetic properties.
Incidentally, as a conventional technology relating to the present invention, an output connector of a microphone equipped with a base made of an electrical insulator mounted at a rear end of a microphone grip of a condenser microphone, wherein a grounding pin and two signal pins on a hot side and a cold side are provided on the base by passing through it and the grounding pin is connected to the microphone grip via predetermined conducting means, characterized in that at least a top face and a circumferential surface of the base are covered with an electrostatic shield member that is non-conducting to each of the signal pins and conducting to the grounding pin is known (See Patent document 1).
Also, a microphone apparatus is known, wherein a sound collecting pore is provided in a cabinet of the microphone apparatus, a microphone is fixed in the microphone apparatus on a central axis of the sound collecting pore, a conductive net using a conductive material is provided between the sound collecting pore and a sound input surface of the microphone, the cabinet is blocked from the outside by filling the sound collecting pore with the conductive net, and the conductive net is grounded so that, when an object charged with static electricity approaches the sound collecting pore, static electricity discharged from the object is grounded through the conductive net (See Patent document 2).                [Patent document 1] Japanese Patent Application Laid-Open No. 2005-94575        [Patent document 2] Japanese Patent Application Laid-Open No. 2005-86231
An invention described in Patent document 1 is related to a grounding structure between a microphone grip and a grounding pin of an output connector, and an invention described in Patent document 2 is related to a structure in which a sound collecting pore of a microphone is covered with a conductive net and the conductive net is grounded. No patent document that has disclosed an installation structure of an output transformer of a microphone like the present invention could be found.


A warming device includes a clinical garment having an inside surface supporting a convective apparatus with multiple separately inflatable sections, each adapted to enable a particular mode of warming.

A warming device that may be used perioperatively includes a clinical garment and convective apparatus with multiple separately-inflatable sections supported on the inside of the garment, each section adapted to enable a particular mode of warming.
Convective devices that transfer heat to a human body are known. For example, there are devices that receive a stream of warmed pressurized air, inflate in response to the pressurized air, distribute it within a pneumatic structure, and emit the warmed air onto a body. These devices are typically called "thermal blankets", "convective thermal blankets" or "covers". Arizant Healthcare Inc., the assignee of this application, makes and sells such thermal blankets under the BAIR HUGGER® brand. One such device is the Model 522 Upper Body Blanket.
Use of the term "convective" to denote the transfer of heat between a warming device and a body refers to the principal mode of heat transfer, it being understood that heat may at the same time be transferred between a convective warming device and a body by conduction and radiation, although not to the degree of convection.
Convective warming has been used with increasing frequency to prevent or mitigate hypothermia during medical treatment. However, with the expansion of convective warming to treat core body cooling, it becomes apparent that it has manifold medical uses.
For example, a recent invention disclosed in the referenced Publication No. WO 2003/086500 adapts a clinical garment such as a robe or gown to receive a convective warming device in order to warm a person wearing the garment in a clinical setting for comfort and mobility of the person. Arizant Healthcare Inc., the assignee of this application, makes and sells such warming devices under the BAIR PAWS® brand. These devices are intended to warm patients prior to surgery, and there is a need to further adapt such a combination for use perioperatively.
The term "perioperative" is defined in the PDR Medical Dictionary, Second Edition, (Medical Economics Company, 2000), as "around the time of operation." The perioperative period is characterized by a sequence including the time preceding an operation when a patient is being prepared for surgery ("the preoperative period"), followed by the time spent in surgery ("the intraoperative period"), and by the time following an operation when the patient is closely monitored for complications while recovering from the effects of anesthesia ("the postoperative period").
According to Mahoney et al. (Maintaining intraoperative normothermia: A meta-analysis of outcomes with costs. AANA Journal. 4/99; 67, 2:155-164.), therapeutic warming is employed during at least the intraoperative period in order to prevent or mitigate hypothermia. In fact, it is increasingly manifest that maintenance of normothermia perioperatively enhances the prospects for a quick, successful recovery from surgery. The effectiveness of therapeutic warming depends upon delivery of enough heat to a patient's body to raise the patient's core body temperature to, or maintain it within, a narrow range, typically around 37° C. This range is called "normothermic" and a body with a core temperature in this range is at "normothermia." Hypothermia occurs when the core body temperature falls below 36° C.; mild hypothermia occurs when core body temperature is in the range of 34° C. to 36° C. Therefore, "perioperative therapeutic warming" is warming therapy capable of being delivered during one or more of the perioperative periods for the prevention or treatment of hypothermia.
Therapeutic warming is contrasted with "comfort warming" which is intended to maintain or enhance a patient's sense of "thermal comfort". Of course, therapeutic warming may also comfort a patient by alleviating shivering or a feeling of being cold, but this is a secondary or ancillary effect. And conversely, there may be a secondary or ancillary therapeutic effect derived from the application of thermal comfort treatments such as the relief of patient anxiety. Thermal comfort is a subjective notion; however, the environmental conditions necessary to produce a sense of thermal comfort in a population of human beings are known and well tabulated. For example, Fanger (Thermal Comfort: Analysis and Applications of Environmental Engineering. Danish Technical press, Copenhagen, 1970) defines thermal comfort as "that condition of mind which expresses satisfaction with the thermal environment." Even when a patient is normothermic, less than ideal environmental conditions can result in acute feelings of discomfort. Under normothermic conditions, thermal comfort is largely determined with reference to skin temperature, not core body temperature. Comfort warming is warming applied to a patient to alleviate the patient's sense of thermal discomfort.
Therapeutic warming may be indicated during any one or more of the perioperative periods. For example, for a short operation in a surgery with no warming equipment available, a person may be warmed preoperatively in a preparation area to raise mean body temperature to a level higher than normal in order to store enough thermal energy to maintain normothermia, without heating, intraoperatively. After surgery, it may be necessary to apply therapeutic warming in a recovery area to raise the core temperature to normothermia and maintain it there for a period of time while anesthesia wears off. Alternatively, for a long surgery in an arena with heating equipment available, a person may be warmed for comfort before surgery and warmed therapeutically during and after surgery.
Thermal blankets are typically used for therapeutic heating. An example is found in U.S. Pat. No. 6,524,332, "System and Method for Warming a Person to Prevent or Treat Hypothermia", commonly owned with this application. Thermal blanket designs have converged on a lightweight inflatable structure made of a flexible material which distributes warmed pressurized air over or against a permeable blanket surface that faces some portion of a patient's body and emits the distributed heated air through small apertures or interstices in the surface.
Thermal blanket design has been adapted for comfort warming by convective means such as those described in the referenced U.S. patent applications, and the referenced Publication No. WO 03/086500.
When delivered by convective devices, therapeutic warming is distinguished from comfort warming by intended effects and by the parameters of heat delivery that produce those effects. In this regard, a convective warming system typically includes a source of warmed pressurized air (also called a heater/blower unit, a forced air warming unit, a heater unit, etc.), a convective device such as a thermal blanket (which is, typically, inflatable), and a flexible conduit or air hose connecting the heater/blower unit with the thermal blanket. Use of such a system for a particular type of warming requires delivery of warmed air through a convective device at parametric values that achieve a particular objective. For example, for comfort warming, the temperature at the hose end, prior to the air entering the pneumatic convective device, may range from ambient to 42° C. (WO 03/086500 at page 11, lines 24-26). The conditions by which a convective device produces thermal comfort in normothermic individuals at steady state are significantly different from those necessary to treat hypothermia. Typically the conditions for thermal comfort are met in a system with a relatively low capacity heater/blower unit, while those in a therapeutic warming system are achieved with a relatively high capacity heater/blower unit. The different capacities have led to use of air hoses with different capacities, with those delivering air flow for thermal comfort typically having smaller diameters than those serving a therapeutic warming requirement. The result is a divergence of designs leading to installation of different air delivery infrastructures for therapeutic and comfort warming.
Health care cost is an issue of high importance. The cost of warming perioperatively by convection is directly related to the number of perioperative periods in which a person is warmed; the cost increases when different convective warming apparatus are used in different periods to accomplish different goals. For example, when comfort and mobility are objectives of warming a person during the preoperative period and therapy is the objective of warming during one or more of the intraoperative and postoperative periods, it is presently necessary to use different convective warming configurations. Manifestly, if one convectively-operating warming device could be used or adapted to be used perioperatively, significant savings in thermal care could be realized.

This patent is subject to a terminal disclaimer.


The present disclosure concerns embodiments of an operating support that supports a surgeon in a sitting position straddling a patient. By straddling the patient, the surgeon is ideally positioned to perform certain types of laparoscopic surgery, such as pelvic surgery, which requires the use of relatively long surgical instruments. The operating support supports the surgeon in a more ergonomically correct position that reduces the stress and strain on the surgeon's body as compared to the conventional technique of performing laparoscopic surgery in a standing position at one side of the operating table.

During laparoscopic surgery, the surgeon typically stands to one side of the operating table while manipulating relatively long instruments and while viewing the procedure on a video monitor. Unfortunately, the surgeon has little opportunity to move the body and change posture, which often leads to fatigue and pain. Thus, there is a strong need for an apparatus to support the surgeon during such procedures in a manner that reduces the stress and strain on the surgeon's body.


A switched reluctance machine comprising a housing, a stator attached to the housing and a rotor mounted within the housing. The stator including teeth wound with electrical coils which are connected to form phase windings. The rotor comprising a series of laminates including teeth pressed onto a shaft. According to the present invention, at least one set of opposing phase wound stator teeth comprise permanent magnets.

Known generators adaptable for use in aircraft engines include flux switch generators, permanent magnet generators, Lundell Permanent Magnet Generators, Wound Rotor Synchronous Generators, Homopolar Generators, Hybrid Homopolar Generators, Slave Regulated Generators and Switched Reluctance Machines. Switched reluctance (SR) machines conventionally have multiple poles on both the stator and rotor; that is, they are doubly salient. In switched reluctance machines, there is a concentrated winding on each of the stator poles, but no windings or magnets on the rotor. Each pair of diametrically opposed stator pole windings is connected in series or parallel to form an independent machine phase winding of the multiphase SR machine. Torque is produced by switching current in each machine phase winding in a predetermined sequence that is synchronized with angular position of the rotor, so that a magnetic force of attraction results between the rotor poles and stator poles. Current is switched off in each phase before the rotor poles rotate past the aligned position. The torque developed is independent of the direction of current flow, so that unidirectional current pulses synchronized with rotor movement can be applied to the stator pole windings by an inverter using unidirectional current switching elements, such as transistors or thyristors. For use as a generator, the current pulses in each machine phase winding are simply shifted so that current flows when the rotor poles are moving past alignment towards the unaligned position.
A SR motor drive or generator system operates by switching the machine phase currents on and off in synchronism with rotor position. That is, by properly positioning the firing pulses relative to rotor angle, forward or reverse operation and motoring or generating operation can be obtained. Usually, the desired phase current commutation is achieved by feeding back a rotor position signal to a controller from a shaft angle transducer, e.g. an encoder or a resolver. However, in order to reduce size, weight and cost in SR motor drives and generating systems, techniques for indirect rotor position sensing have been developed, thus eliminating the need for a shaft angle transducer. Current regulators are typically employed for controlling phase current amplitudes in a SR machine.
Control Alternators used in present day aircraft engines are normally driven by the engine shaft and, as a result the output may be subject to voltage variations of 10 to 1. Therefore, voltage from the permanent magnet generators used for this purpose can not be regulated easily. If an SCR controlled rectifier system is used to maintain constant output voltage from 10% speed to 105% speed, the rectifiers must be large enough to block the high voltages generated at top engine speed. Further, a failure in the controlled rectifier may expose the rest of the electrical circuitry to excessive voltages.
Alternatively, a "shunt regulator" may be used at high speeds to short the alternator such that only a percentage (e.g., 10%) of the generated voltage reaches the electrical circuitry. A failure in the solid state switches of a shunt regulator (controlled rectifier) does not expose the other circuitry to high voltages because the alternator output is effectively shorted. Therefore, the alternator must be designed to handle continuous short circuit operation in the event of a failure.
It would, therefore, be advantageous to design a switched reluctance machine which does not expose the low voltage electronic circuitry to high voltages in the event of a failure, nor does it expose the generator to continuous short circuit operation and excessive temperatures.
It will also be noted that, starting a conventional switched reluctance generator normally requires a battery or other power source to energize the phase windings.

Switched reluctance machine including permanent magnet stator poles


Systems and methods for harvesting geothermal energy use temperature-based flow control to optimize the extraction of thermal energy from a geothermal reservoir. In one example, a thermal transport fluid is flowed into a wellbore traversing a thermal reservoir of a formation. Flow of the thermal transport fluid into and out of the thermal reservoir is dynamically controlled at each of a plurality of injection and/or return locations in response to a downhole parameter such as temperature. For example, flow may be controlled so that the flow into the thermal reservoir is greater at the injection locations where the temperature is hotter and that the flow out of the thermal reservoir is greater at the return locations where the temperature is hotter. The thermal transport fluid produced from the return locations is then conveyed to surface to extra the thermal energy.

The energy industry continually strives to supplement existing, well-developed energy resources and technologies, such as by developing emerging energy sources and discovering new energy sources. These supplemental forms of energy may be useful, both to provide redundant energy and power system in the short term and to increase energy availability and reliability in the longer-term. So-called "alternative" energy sources, including those that are not so economically viable today, may also be phased in over a long time scale as other resources gradually deplete.
One area of robust development is in geothermal energy production. Geothermal energy production is a way to harvest existing energy in the form of heat inside the earth (geothermal energy) and converting that thermal energy into other forms of useful energy. Geothermal energy production systems have been constructed in an effort to extract thermal energy below ground and convert it to electricity.
Globally, it has been speculated that significant levels of geothermal power can be generated using closed-loop geothermal systems that exploit hot and deep geothermal resources. While these systems can be commercialized in some locations presently, the industry generally seeks improvements in well construction technology to broaden the range of projects that can be more economically viable. Such improvements may include, for example, efforts to reduce the cost of drilling, improving materials, and advancing well completion systems used to harvest geothermal energy.


The present invention is a corner protection mask design that protects chip corners from undercutting during anisotropic etching of wafers. The corner protection masks abut the chip corner point and extend laterally from segments along one or both corner sides of the corner point, forming lateral extensions. The protection mask then extends from the lateral extensions, parallel to the direction of the corner side of the chip and parallel to scribe lines, thus conserving wafer space. Unmasked bomb regions strategically formed in the protection mask facilitate the break-up of the protection mask during etching. Corner protection masks are useful for chip patterns with deep grooves and either large or small chip mask areas. Auxiliary protection masks form nested concentric frames that etch from the center outward are useful for small chip mask patterns. The protection masks also form self-aligning chip mask areas. The present invention is advantageous for etching wafers with thin film windows, microfine and micromechanical structures, and for forming chip structures more elaborate than presently possible.

The present invention relates to wet chemical etching of wafers. In particular, the present invention relates to improved space-saving mask designs that prevent undercutting at feature area corners when forming deep grooves using anisotropic etching methods.
In the semiconductor industry, wafers that have integrated circuits on them are generally separated into chips with a diamond saw, or sometimes by scribing and cleaving. With the recent introduction of chips having micromechanical devices or thin film windows, sawing tends to be wasteful because the devices are fragile and can be easily broken while sawing the wafer. To alleviate this problem, these wafers are separated by scribing and cleaving. Scribe lines are generally made using anisotropic etching techniques, but problems with undercutting arise because the chip corners are not along well-defined crystal planes.
For example, in typical anisotropic etching of silicon (100) wafers, the chip mask patterns are usually bounded by masks with edges along the (111) planes. The (111) planes etch much more slowly than other planes when using certain etchants and thus serve as effective etch-stops along the edges of the chip masks. However, chip corners do not line up with the (111) planes, and although concave corners also serve as etch-stops, convex corners will etch much more quickly than the mask boundaries along the (111) planes. This preferential etching causes considerable undercutting at the convex corners of the chip masks when etching deep grooves.
Corner undercutting is particularly troubling for two types of chip mask patterns. The first pattern has large chip areas, preferably with deep, narrow grooves between the chips. The second pattern has very small chip areas with deep, wide grooves between the chips. The development of corner compensation techniques reduces or eliminates the undercutting of chip corners while etching deep grooves.
The conventional corner compensation method for (100) silicon wafers involves forming a mask extension directed away from a chip mask corner along the (111) direction. The convex corners on the end of the extension are undercut and etched away, causing the extension to shorten. The length of the extension is formed to be completely etched when the groove has reached the proper depth. Etching is stopped before the chip corners are undercut.
Conventional mask extensions are straight and extend from the corners of the mask and lay across the adjacent scribe lines. Since a longer etching time increases the necessary length of the extensions, etching deeper grooves requires the extensions to be longer to avoid undercutting at the corners. Consequently, deeper grooves must also be wider because the extensions must be long and lie across the region where the groove is formed. This wide spacing between the masks due to the length of the extensions results in a large amount of wasted wafer space. This corner compensation technique is also unsuitable for producing high quality scribe lines, which are needed at boundaries between chip areas having delicate micromechanical devices or thin film windows.
Even in small chip patterns, which require deep, wide grooves, and where much unmasked wafer space surrounds the chip masks, the conventional corner compensation technique still may not protect chip corners adequately. Plenty of space exists in these patterns to form long extensions by the conventional technique, but these extensions, unfortunately, are very narrow. Narrow extensions are formed since the extensions are narrower in width than the chip itself, which already has a small area. These long, thin extensions are undercut too rapidly to create deep grooves and preserve the chip corners.
Different variations on the mask extension theme have been developed. The Wu method uses extensions bounded by beveling planes at the chip corners (Wu et al., Sensors and Actuators 18:207 (1989)). Chang et al. describe the use of compensation "streets", in which compensation areas abut the sides of the chips, forming straight extensions at the chip corners at a 45.degree. angle to the chip sides (Solid-State Sensor and Actuator Workshop, June 6-9, 1988). Mayer et al. developed compensation structures in which the main element is a straight masked band extending at an angle from a chip corner (J. Electrochem. Soc. 137:3947 (December 1990)). The two long sides of this band fan out into narrow beams.
All of these corner compensation structures are inadequate for large chip patterns because of space considerations. The mask extensions, whether formed into streets or a fan of beams, or bounded by beveled planes, leave open space that limits the compactness of chips on a wafer. Conventional techniques produce wafers with either deep, narrow grooves and an unacceptable amount of undercutting at convex corners or deep, wide grooves without undercutting at the corners. Both choices have serious deficiencies.
Conventional techniques are also inadequate for small chip patterns, for the mask extensions formed at the convex corners are extremely narrow and undercut too quickly to form deep, wide grooves. In particular, the chip area is too small to permit the formation of an elaborate fan of beams like the Mayer structures. Conventional methods produce either deep, wide grooves with unacceptable undercutting or shallow, wide grooves without undercutting. Again, the choices presented by the conventional compensation techniques do not protect the desired chip patterns.
Thus, a need exists for an improved method of eliminating undercutting at convex corners during the anisotropic etching of wafers. For large or small chip patterns, an improved method would save space on the individual chips and would increase the number of chips that are made from a wafer. Also, the advent of new, mechanically delicate chips requires a gentle method of separating wafers into chips. The present invention solves all these problems by providing a method of making narrow or wide deep grooves without undercutting the chip area corners. A greater variety of elaborate, customized, and microfine structures on wafers become possible using the present invention.

Method for protecting chip corners in wet chemical etching of wafers


A system and method for equalizing a signal is provided. In one implementation, the method includes generating a partially equalized signal from an input signal based on a plurality of coefficients associated with a feed-forward equalizer (FFE); generating decoded bit values based on the partially equalized signal, the decoded bit values being an equalized output signal; measuring error in the partially equalized signal; and adjusting the coefficients associated with the feed-forward equalizer (FFE) based on the error measured in the partially equalized signal. Values of the coefficient are not used to adjust of the coefficients associated with the feed-forward equalizer (FFE).

Adaptive equalizer systems determine and provide equalizations required for a received waveform to ultimately resemble the originally transmitted waveform. There are currently systems on the market which use transversal filters to equalize a signal to correct the impairments in the signal caused by various sources (e.g., inter-symbol interference (ISI) cross-talk, polarization mode dispersion (PMD)). Most implementations must recover the timing data before, or at the same time as the equalizer, so that it can properly process data. For example, typically in DSP equalizers all tap values (i.e., the intermediate signal values at the output of a delay stage of the equalizer) must be digitized and known.
Accordingly, what is needed is a system and method for providing an equalizer of signals for a circuit which does not require the timing recovery of data. The present invention addresses such a need.


A method and apparatus are presented that can analyze the performance of an integrated circuit design at multiple corners, under multiple modes, and for multiple objectives efficiently and simultaneously. The extraction, timing analysis, and optimization functions are integrated into a mechanism that provides a novel problem formulation. A plurality of virtual timing graphs are maintained and updated simultaneously by providing a data structure that can efficiently store operating data for an arbitrary number of conditions at each node. This data structure is populated according to the design, and as optimizations are made, the operating data for all design conditions is updated simultaneously. Timing violations can be reported across all corners and modes. By integrating this multi-corner multi-mode analysis with circuit optimization, a convergent mechanism is provided. In this way, design constraints are evaluated simultaneously for an arbitrary number of design conditions.

Integrated circuit design is an increasingly complex process and relies heavily on the use of computer-based tools. As designs get larger, and the critical dimension in fabrication processes shrink, the problem of evaluating and optimizing the physical design is becoming more burdensome. Current generation integrated circuits are being designed for processes with features sizes of 90 nanometers, 65 nanometers and smaller. Technology with feature sizes in this range are sometimes referred to as "deep-submicron" or "nanometer" technologies.
In nanometer technologies, many electrical properties that were previously second and third order effects have come to play a major role in determining circuit performance and power consumption. One reason for this is that shrinking geometries have caused the variability of design parameters to increase. For example, interconnect geometry parameters such as wire thickness and resistivity have an increasingly higher variation as a percentage of the total thickness and resistivity. Variability can be exhibited both inter-chip and intra-chip. Variability affects both device parameters and interconnect parameters and directly determines the margin and achievable yield of an integrated circuit design.
Variability comes from many sources. We can generally classify the source of variations into four groups: environmental, manufacturing, reliability and operational.
a. Environmental Variations
Environmental variations arise during the operation of a chip and include both global (inter-chip) and local (intra-chip) environmental variations. Global environmental variations include variations in chip ambient temperature and supply voltage. Local environmental variations are caused by variations in power supply, local coupling, and temperature across the chip.
Global environmental variations such as ambient temperature and supply voltage can change the electrical characteristics of devices. Worst case timing has been traditionally modeled using parameters characterizing a low voltage, a slow process and a high temperature. This approach is not always sufficient for nanometer technologies because such processes sometimes exhibit inverted temperature behavior, whereby the worst timing occurs at a low temperature rather than a high temperature. This inverted temperature behavior can be traced to transistor current-voltage (IV) characteristics. The transistor saturation current is dominated by: temperature mobility dependency above the temperature neutral point, and temperature threshold dependency below the temperature neutral point. The temperature inversion effect typically varies for each library cell and may get worse when lower operating voltages are used.
Local environmental variations are caused by the operation of the chip and include such local effects as:
Device voltage variations due to voltage drop (IR drop) and ground bounce
Delay and slew variations due to crosstalk
Input pin capacitance variation due to slew and state dependency
Device performance degradation due to negative bias temperature instability
IR drop and crosstalk induced variations are more prominent in nanometer technologies than in previous technologies. Previously, the capacitance seen at the input of a CMOS cell has been considered independent of all factors external to the cell. The increasing drain-to-gate capacitance has changed this assumption. Now it is often important to consider the Miller Capacitance effect, making the effective input capacitance a function of the load capacitance and the input slew. Effective pin capacitance usually increases with slew and decreases with cell output load. The dependency of input capacitance on the state of the cell adds further modeling complications.
b. Manufacturing Variations
Manufacturing variations result in permanent structural device and interconnect variations. These variations arise due to processing and masking limitations, and result in random or spatially varying deviations from designed parameter values. Manufacturing variations affect both interconnect and device characteristics and are experienced both globally (inter-chip) and locally (intra-chip).
Global manufacturing variations include global geometric variations in device and interconnect as well as material parameter variation in device and interconnect. Device geometric variations such as effective channel length variation and film thickness variation can result in systematic chip-to-chip threshold voltage (Vt) and leakage current variations. This threshold voltage variation affects delay and leakage power. Similarly deviations in the width of lower metal layers due to proximity and lithographic effects can directly impact line resistance as well as coupling capacitance. Global variation in metal and dielectric thickness also leads to global resistance and capacitance variations.
Local manufacturing variations include device and interconnect geometry variations due to local layout as well as random material parameter variation. Device effective channel length has some plasma etch dependencies (which depends on local layout) and it manifests itself in the form of local threshold voltage (Vt) variations. Interconnect local geometric variations include local layout dependent width and spacing variation, dishing and erosion of metal, as well as dielectric thickness variation.
Interconnect line width and spacing deviations arise primarily due to photolithographic and etch dependencies. For lower metal layers, lithographic and proximity effects may be important while at other levels aspect ratio dependent etch effects, which depend on local layout can be significant. These deviations directly impact interconnect parasitics and result in performance and signal integrity degradation.
Significant local metal thickness variation (10–20 percent) has been observed for nanometer copper technologies resulting in dishing and erosion. Similarly, chemical mechanical planarization (CMP) can introduce strong dielectric thickness variations across the die. Selective process bias (SPB) based on width and spacing to adjacent metal has been used to address local layout effect on interconnect. In nanometer technologies, dishing and erosion effects need to be modeled as well.
FIG. 1 is an illustration of one aspect of the problem addressed by the present invention. FIG. 1 shows local and global variation of inter-layer dielectric thickness across a wafer. Each square in FIG. 1 represents a single die and the entire surface illustrated represents a single wafer. The local variation of inter-layer dielectric thickness is represented by the vertical range of a single square, while the global variation is represented by the vertical range of the entire surface.
c. Reliability Variations
Reliability variations are caused by various wear-out mechanisms, in which device performance degrades over time. It should be ensured that the degradation does not cause functional or performance failures during or after the degradation. In nanometer technologies, negative bias temperature instability (NBTI) is expected to cause significant P-transistor performance degradation over device lifetime. It degrades the threshold voltage (Vt) as well as drive current of the P transistors. This is especially problematic for pull-up devices and can cause larger delays.
In some cases, it is desirable to model wear-out mechanisms for clock signals (which experience more switching over the lifetime of the chip) differently than for ordinary logic signals. Reliability variations can be modeled as either global variations (considering new and old characteristics globally as different operating points), or as local variations (considering old and new characteristics locally as different device characteristics), or some combination of the two.
d. Operational Variations
Operational variability refers to different operating modes of an IC. For example, an IC may be designed to work in functional mode, test mode, sleep mode, and power-off mode. Different modes come with different design constraints that must be simultaneously analyzed for fast design closure.
e. Traditional Approaches
Traditionally, variability has been handled through two-corner analysis. We use the term "corner" to refer to any combination of process, voltage and temperature (PVT), as well as other environmental, manufacturing or reliability factors. In a traditional two-corner analysis, late (i.e., setup) analysis is carried out for parameters characterizing a weak process, a minimum voltage, and a high temperature, and early (i.e., hold) analysis is carried out for parameters characterizing a strong process, a maximum voltage, and a low temperature. In such traditional approaches, nominal interconnect models are generally used everywhere and a bit of margin is used to cover up uncertainty.
One limitation of a traditional two-corner analysis is that signal integrity problems may be worse at other corners. For example, noise problems may only show themselves at a strong process and high temperature conditions.
Another problem with the traditional approaches is that they model certain variations as uncertainty when they are actually deterministic. In fact, a substantial portion of local variability is design and layout dependent and therefore deterministic. Similarly, many global variability sources (e.g., ambient temperature) can be known in advance and deterministically modeled. Operational variability is always deterministic.
Ideally, deterministic variability impact can be assessed and tuned out of the design. However, lack of modeling resources often transform variability into uncertainty and effectively convert systematic variation into randomized one.
Treating deterministic variability as uncertainty is both pessimistic and risky at the same time. It is pessimistic as is the nature of bounding methods that seek to deliver guarantees on the earliest and latest arrival times. Yet, it is risky because it is not possible to conduct a bounding analysis using only two corners.
Traditional methods require users to run each design variability corner individually and verify performance. At most, two-corner single-mode support is implemented in existing solutions. Thus, users are required to ping-pong between each variability corner and between different modes to fix all the timing paths in all the corners.
Another approach, statistical timing, has been proposed by some as a solution for handling variability. However, verifiable statistical device and interconnect models are not yet available. Also, there are significant hurdles involved in getting library vendors and designers to accept statistical timing analysis.
Thus, there is a need for a convergent method to handle variability in an integrated fashion to enable simultaneous analysis and optimization of all the different variability effects. Such a comprehensive variability solution is desirable in analysis and implementation tools for designing nanometer ICs in order to minimize systematic yield loss due to variability and achieve yields near defect-density limits.

Method and apparatus for the analysis and optimization of variability in nanometer technologies