The present invention provides methods for the use of copper electroplating compositions. Electroplating compositions of the invention contain an increased brightener concentration that can provide effective copper plate on difficult-to-plate aperture walls, including high aspect ratio, small diameter microvias.

1. Field of the Invention
The present invention relates to copper electroplating solutions, methods for using the solutions and products formed by using such methods and solutions. More particularly, the invention provides electrolytic copper plating solutions that have increased brightener levels and use of same for effective plating of high aspect ratio apertures, e.g. microvias with aspect ratios of at least 4:1 and diameters of 200 nm or smaller.
2. Background
Electroplating articles with copper coatings is generally well known in the industry. Electroplating methods involve passing a current between two electrodes in a plating solution where one electrode is the article to be plated. A common plating solution would be an acid copper plating solution containing (1) a dissolved copper salt (such as copper sulfate), (2) an acidic electrolyte (such as sulfuric acid) in an amount sufficient to impart conductivity to the bath and (3) additives (such as surfactants, brighteners, levelers and suppressants) to enhance the effectiveness and quality of plating. See generally U.S. Pat. Nos. 5,068,013; 5,174,886; 5,051,154; 3,876,513; and 5,068,013 for a discussion of copper plating baths.
Over time, a number of improvements in electroplating techniques have been made as the articles to be plated evolved in degree of difficulty and standards for plating increased. However, even with the improvements in electroplating techniques, circumstances exist that can lead to plating defects.
Copper plating technology has been particularly important in the manufacture of computer circuit boards. More specifically, during circuit board manufacture, copper electrical connections are provided between various board layers by plating board through holes whereby a thin conductive copper conductive is first applied, typically using electroless copper plating techniques, followed by electroplating copper from acid copper solutions.
Copper plating is also employed in circuit board manufacture to plate outer layers where final circuitry is defined. For such applications, panel plating is typically employed, where the full circuit board surface is copper plated followed by photodefining circuitry with a photoresist and then etching in a subtractive process. Alternatively an additive process can be employed, where copper circuits are produced by plating between lines defined by a resist relief image.
More recently, copper plating also has been employed in semiconductor chip manufacture to provide chip interconnections. Traditionally, semiconductors have been interconnected through aluminum conductors. However, industry continually demands enhanced performance, including ultra large-scale integration and faster circuits. Consequently, chip interconnects are required at dimensions of 200 nm and less. At such geometries, the resistivity of aluminum (theoretically 2.65xc3x9710xe2x88x928 ohm/meter at room temperature) is considered too high to allow the electronic signal to pass at required speeds. Copper, with a theoretical resistivity of 1.678xc3x9710xe2x88x928 ohm/meter, is considered a more suitable material to meet the next generation of semiconductor microchips.
Typical processes for defining semiconductor chip interconnects, particularly aluminum interconnects, have involved reactive ion etching of metal layers, e.g. a process that includes metal deposition, photolithographic patterning, line definition through reactive ion etching and dielectric deposition. However, in Cu-based systems, reactive ion etching is not practical as a result of the paucity of copper compounds with vapor pressures sufficient to enable removal of the copper as may be desired.
Consequently, alternative strategies have developed, such as the Damascene process. That process starts with deposition of dielectric typically by chemical vapor deposition of silicon materials or organic dielectrics followed by curing, or spin coating silicon materials or organic dielectrics. Patterning by photolithographic processes and reactive ion etching defines the vias and trenches (interconnects) in the dielectric. Barrier layers are then formed by chemical vapor deposition or other methods to isolate the copper lines from the dielectric. Copper is then deposited and excess material removed by chemical or mechanical polishing processes.
Although conventional copper plating systems can be suitable for plating vias and trenches as small as 300 nm with 4:1 aspect ratios, defects such as seams, voids and inclusions can occur with conventional methods when attempting to plate features that are smaller or have higher aspect ratios. Such defects can occur as a result of conformal copper plating, i.e. where all targeted surfaces are plated at the same rate such that the sidewalls of a via or trench plate together forming a seam or a demarcation of disruption where the copper grains are separated and will not anneal to form a continuous copper wire. Defects also will occur at the top rim of a via hole, where electronic charge density can concentrate and result in rapid copper growth that closes off the via before the via is filled sufficiently with metal. Such inadequate metal fill can result in inclusion and voids, disrupting the ability of the plated metal to carry a coherent signal.
It thus would be desirable to have new electroplating compositions. It would be particularly desirable to have new copper electroplating compositions that can plate effectively (e.g. absence of voids, inclusions and seams) high aspect ratio apertures, including high aspect ratio microvias as discussed above.
We have now found copper electroplating compositions that effectively plate a wide variety of articles, including printed circuit boards and other electronic packaging devices. Compositions and methods of the invention are particularly useful for filling microvias and trenches required by current and anticipated semiconductor fabrication requirements (including microvias having aspect ratios of at least 4:1 and diameters of 200 nm or less) by reliably plating copper deposits that are essentially or completely free of voids, inclusions or other plating imperfections.
Electroplating baths of the invention are characterized in significant part by comprising enhanced brightener concentrations. Without being bound by any theory, it is believed that the higher brightener concentrations can accelerate the plating rate in recesses and microvias as carrier molecules become incorporated into the plating deposit. This is counterintuitive to conventional thought and a completely unexpected result.
In particular, preferred electroplating compositions of the invention have a brightener concentration of at least about 1.5 mg per liter of plating solution (1.5 mg/L), more preferably a brightener concentration of at least about 1.75 mg per liter, still more preferably at least about 2.0, 2.5. 3, 3.5 or 4 mg of brightener per liter of plating solution. Good results have been achieved with even higher brightener concentrations, e.g. copper plating baths having a brightener concentration of at least about 5 mg per liter, or at least about 6, 7, 8, 9, 10, 12, 14, 16, 18, 20 or 25 mg/L, or even higher brightener concentrations such as at least about 30, 35, 40, 45, 50, 55 or 60 mg of brightener per liter of plating solution.
Preferably, the brightener concentration is maintained at such high concentrations throughout the entire or at least substantial portion of a plating cycle. Such maintenance of brightener concentrations entails regular addition of brightener during a plating cycle as the brightener component plates out. Brightener concentrations and replenishment rates during a plating cycle can be readily determined by known methods, such as the CPVS method as disclosed in U.S. Pat. Nos. 5,252,196 and 5,223,118, both assigned to the Shipley Company, or by the cyclic voltammetric stripping (CVS) methods.
In addition to such an elevated brightener concentration, preferably the plating bath also contains a surfactant-type suppressor agent. It has been surprisingly found that use of such a suppressor agent in combination with elevated brightener concentrations can result in effective xe2x80x9cbottom-fillxe2x80x9d copper plating of a microvia or other aperture without defects such as inclusions or voids. In particular, the suppressor enables enhanced plating rate at the bottom of a microvia, permitting copper to plate the entire aperture space in a substantially xe2x80x9cbottom-fillxe2x80x9d manner, without premature sealing of the aperture top that can result in inclusions or voids.
The invention also includes articles of manufacture, including electronic packaging devices such as printed circuit boards, multichip modules, semiconductor integrated circuits and the like that contain a copper deposit produced from a plating solution of the invention. Other aspects of the invention are discussed infra.
Compositions of the invention suitably contain a copper salt, an electrolyte preferably an acidic aqueous solution such as a sulfuric acid solution with a chloride or other halide ion source, and one or more brightener agents in enhanced concentrations as discussed above, and preferably a suppressor agent. The plating compositions also may contain other components such as one or more leveler agents and the like.
As discussed above, electroplating solutions of the invention are particularly effective in plating various articles having microvias with high aspect ratios and small diameters. In particular, solutions of the invention are useful in plating electronic packaging devices such as printed circuit boards, microchip module packaging and blind 3-dimensional structures, particularly semiconductor integrated circuits and other circuit systems. The electroplating solutions of the invention are particularly useful to copper fill microvias of such electronic devices without the defects exhibited upon use of prior chemistries. In addition, the invention has application to plating on a wide variety of other polymer and metal substrates.
Electroplating solutions of the invention generally comprise at least one soluble copper salt, an electrolyte and a brightener component. More particularly, electroplating compositions of the invention preferably contain a copper salt; an electrolyte, preferably an acidic aqueous solution such as a sulfuric acid solution with a chloride or other halide ion source; and one or more brightener agents in enhanced concentrations as discussed above. Electroplating compositions of the invention also preferably contain a suppressor agent. The plating compositions also may contain other components such as one or more leveler agents and the like.
A variety of copper salts may be employed in the subject electroplating solutions, including for example copper sulfates, copper acetates, copper fluoroborate, and cupric nitrates. Copper sulfate pentahydrate is a particularly preferred copper salt. A copper salt may be suitably present in a relatively wide concentration range in the electroplating compositions of the invention. Preferably, a copper salt will be employed at a concentration of from about 10 to about 300 grams per liter of plating solution, more preferably at a concentration of from about 25 to about 200 grams per liter of plating solution, still more preferably at a concentration of from about 40 to about 175 grams per liter of plating solution.
Plating baths of the invention preferably employ an acidic electrolyte, which typically will be an acidic aqueous solution and that preferably contains a halide ion source, particularly a chloride ion source. Examples of suitable acids for the electrolyte include sulfuric acid, acetic acid, fluoroboric acid, methane sulfonic acid and sulfamic acid. Sulfuric acid is generally preferred. Chloride is a generally preferred halide ion. A wide range of halide ion concentrations (if a halide ion is employed) may be suitably utilized, e.g. from about 0 (where no halide ion employed) to 100 parts per million (ppm) of halide ion in the plating solution, more preferably from about 25 to about 75 ppm of halide ion source in the plating solution.
The invention also includes electroplating baths that are substantially or completely free of an added acid and may be neutral or essentially neutral (e.g. pH of at least less than about 8 or 8.5). Such plating compositions are suitably prepared in the same manner with the same components as other compositions disclosed herein but without an added acid. Thus, for instance, a preferred substantially neutral plating composition of the invention may have the same components as the plating bath of Example 1 which follows, but without the addition of sulfuric acid.
As discussed above, it has been discovered that by increasing brightener concentration beyond conventional levels, uniform plating of particularly high aspect ratio microvias and other difficult-to-plate apertures is now possible.
In particular, copper electroplating compositions are provided that have a brightener agent concentration of at least about 1.5 mg per liter of plating solution (1.5 mg/L), compared to typical brightener concentrations ranging from about 0.05 to 1.0 mg/L in prior composition. More preferably, in electroplating baths of the invention, the brightener concentration is at least about 1.75 mg/L, and still more preferably, at least about 2, 2.5, 3, 3.5 or 4 mg/L. Even higher brightener concentrations will be suitable or even preferred, e.g. at least about 10, 15, 20, 30, 40, 50 mg of brightener per liter of plating solution. A brightener concentration of from about 20 to about 200 mg per liter of plating solution will be suitable for many applications.
Preferably, the brightener concentration is maintained throughout the entire electroplating process, or throughout at least a substantial portion of the plating process, e.g. at least about 50, 60, 70, 80 or 90 percent of the duration of the plating process. As discussed above, since brightener levels are depleted as the electroplating progresses, the brightener component is preferably regularly replenished during plating to maintain a steady state brightener concentration.
A wide variety of brighteners, including known brightener agents, may be employed in the copper electroplating compositions of the invention. Typical brighteners contain one or more sulfur atoms, and typically without any nitrogen atoms and a molecular weight of about 1000 or less. Brightener compounds that have sulfide and/or sulfonic acid groups are generally preferred, particularly compounds that comprise a group of the formula Rxe2x80x2xe2x80x94Sxe2x80x94Rxe2x80x94SO3X, where R is an optionally substituted alkyl (which include cycloalkyl), optionally substituted heteroalkyl, optionally substituted aryl group, or optionally substituted heteroalicyclic; X is a counter ion such as sodium or potassium; and Rxe2x80x2 is hydrogen or a chemical bond (i.e. xe2x80x94Sxe2x80x94Rxe2x80x94SO3X or substituent of a larger compound). Typically alkyl groups will have from one to about 16 carbons, more typically one to about 8 or 12 carbons. Heteroalkyl groups will have one or more hetero (N, O or S) atoms in the chain, and preferably have from 1 to about 16 carbons, more typically 1 to about 8 or 12 carbons. Carbocyclic aryl groups are typical aryl groups, such as phenyl and naphthyl. Heteroaromatic groups also will be suitable aryl groups, and typically contain 1 to about 3 N, O or S atoms and 1-3 separate or fused rings and include e.g. coumarinyl, quinolinyl, pyridyl, pyrazinyl, pyrimidyl, furyl, pyrrolyl, thienyl, thiazolyl, oxazolyl, oxidizolyl, triazole, imidazolyl, indolyl, benzofuranyl, benzothiazol, and the like. Heteroalicyclic groups typically will have 1 to 3 N, O or S atoms and from 1 to 3 separate or fused rings and include e.g. tetrahydrofuranyl, thienyl, tetrahydropyranyl, piperdinyl, morpholino, pyrrolindinyl, and the like. Substituents of substituted alkyl, heteroalkyl, aryl or heteroalicyclic groups include e.g. C1xe2x88x928 alkoxy; C1xe2x88x928 alkyl, halogen, particularly F, Cl and Br; cyano, nitro, and the like.
More specifically, useful brighteners include those of the following formulae:
XO3Sxe2x80x94Rxe2x80x94SH
XO3Sxe2x80x94Rxe2x80x94Sxe2x80x94Sxe2x80x94Rxe2x80x94SO3X and
XO3Sxe2x80x94Arxe2x80x94Sxe2x80x94Sxe2x80x94Arxe2x80x94SO3X
where in the above formulae R is an optionally substituted alkyl group, and preferably is an alkyl group having from 1 to 6 carbon atoms, more preferably is an alkyl group having from 1 to 4 carbon atoms; Ar is an optionally substituted aryl group such as optionally substituted phenyl or naphthyl; and X is a suitable counter ion such as sodium or potassium.
Some specific suitable brighteners include e.g. n,n-dimethyl-dithiocarbamic acid-(3-sulfopropyl)ester; 3-mercapto-propylsulfonic acid-(3-sulfopropyl)ester; 3-mercapto-propylsulfonic acid (sodium salt); carbonic acid-dithio-o-ethylester-s-ester with 3-mercapto-1-propane sulfonic acid (potassium salt); bissulfopropyl disulfide; 3-(benzthiazolyl-s-thio)propyl sulfonic acid (sodium salt); pyridinium propyl sulfobetaine; 1-sodium-3-mercaptopropane-1-sulfonate; sulfoalkyl sulfide compounds disclosed in U.S. Pat. No. 3,778,357; the peroxide oxidation product of a dialkyl amino-thiox-methyl-thioalkanesulfonic acid; and combinations of the above. Additional suitable brighteners are also described in U.S. Pat. Nos. 3,770,598, 4,374,709, 4,376,685, 4,555,315, and 4,673,469, all incorporated herein by reference. Particularly preferred brighteners for use in the plating compositions of the invention are n,n-dimethyl-dithiocarbamic acid-(3-sulfopropyl)ester and bis-sodium-sulfonopropyl-disulfide.
In addition to the copper salts, electrolyte and brightener, plating baths of the invention optionally may contain a variety of other components, including organic additives such as suppressors agents, leveling agents and the like.
As discussed above, use of a suppressor agent in combination with an enhanced brightener concentration is particularly preferred and provides surprisingly enhanced plating performance, particularly in bottom-fill plating of small diameter and/or high aspect ratio microvias.
Without being bound by any theory, it is believed such enhanced bottom-fill plating may occur due to the concentration of the suppressor agent being comparatively decreased at a bottom of a microvia as a result of diffusion effects through the length of the microvia. That reduced suppressor concentration results in an enhanced copper plating rate at the microvia bottom regions.
In contrast, at the surface of the article to be plated (at the top of the microvia), the suppressor agent concentration remains relatively constant and at an elevated level relative to the microvia bottom regions. Consequently, the area at a microvia top has a comparatively suppressed plating rate because of the enhanced suppressor agent concentration relative to the microvia bottom regions.
Preferred suppressor agents for use in the compositions of the invention are polymeric materials, preferably s having hetero atom substitution, particularly oxygen linkages. Generally preferred suppressor agents ate generally high molecular weight polyethers, such as those of the following formula:
Rxe2x80x94Oxe2x80x94(CXYCXxe2x80x2Yxe2x80x2O)nH
where R is an aryl or alkyl group containing from about 2 to 20 carbon atoms; each X, Y, Xxe2x80x2 and Yxe2x80x2 is independently hydrogen; alkyl preferably methyl, ethyl or propyl; aryl such as phenyl; aralkyl such as benzyl, and preferably one or more of X, Y, Xxe2x80x2 and Yxe2x80x2 is hydrogen; and n is an integer between 5 and 100,000. Preferably, R is ethylene and n is greater than 12,000.
More specifically, surfactants useful in the present invention include e.g. amines such as ethoxylated amines, polyoxyalkylene amines and alkanol amines; amides; polyglycol-type wetting agents, such as polyethylene glycols, polyalkylene glycols and polyoxyalkyene glycols; high molecular weight polyethers; polyethylene oxides (mol. wt. 300,000 to 4 million); block copolymers of polyoxyalkyenes; alkylpolyether sulfonates; complexing surfactants such as alkoxylated diamines; and complexing agents for cupric or cuprous ions which include entprol, citric acid, edetic acid, tartaric acid, potassium sodium tartrate, acetonitrile, cupreine and pyridine.
Particularly suitable surfactants for plating compositions of the invention are commercially available polyethylene glycol copolymers, including polyethylene glycol copolymers. Such polymers are available from e.g. BASF (sold by BASF under Tetronic and Pluronic tradenames), and copolymers from Chemax. A butylalcohol-ethylene oxide-propylene oxide copolymer having an Mw of about 1800 from Chemax is particularly preferred.
Surfactants are typically added to copper electroplating solutions in concentrations ranging from about 1 to 10,000 ppm based on the weight of the bath, more preferably about 5 to 10,000 ppm.
Use of one or more leveling agents in plating baths of the invention is generally preferred. Examples of suitable leveling agents are described and set forth in U.S. Pat. Nos. 3,770,598, 4,374,709, 4,376,685, 4,555,315 and 4,673,459. In general, useful leveling agents include those that contain a substituted amino group such as compounds having Rxe2x80x94Nxe2x80x94Rxe2x80x2, where each R and Rxe2x80x2 is independently a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group. Typically the alkyl groups have from 1 to 6 carbon atoms, more typically from 1 to 4 carbon atoms. Suitable aryl groups include substituted or unsubstituted phenyl or naphthyl. The substituents of the substituted alkyl and aryl groups may be, for example, alkyl, halo and alkoxy.
More specifically, suitable leveling agents include e.g. 1-(2-hydroxyethyl)-2-imidazolidinethione; 4-mercaptopyridine; 2-mercaptothiazoline; ethylene thiourea; thiourea; alkylated polyalkyleneimine; phenazonium compounds disclosed in U.S. Pat. No. 3,956,084; N-heteroaromatic rings containing polymers; quaternized, acrylic, polymeric amines; polyvinyl carbamates; pyrrolidone; and imidazole. A particularly preferred leveler is 1-(2-hydroxyethyl)-2-imidazolidinethione. Typical concentrations of leveling agents range from about 0.05 to 0.5 mg per liter of plating solution.
The copper electroplating compositions are suitably used in similar manner as prior copper electroplating baths, except an elevated brightener concentration is employed and preferably maintained at an elevated level throughout a plating cycle.
For instance, with reference to a printed circuit board substrate, a copper clad plastic substrate is typically employed, e.g. a copper clad glass fiber reinforced epoxy panel. Prior to formation of a circuit, apertures, such as microvias, are formed in the board by drilling and metallization. Microvias and other apertures also may be formed by photoimaging. Processes for forming such apertures in electronic device substrates are known and are disclosed e.g. in U.S. Pat. No. 4,902,610; C. Coombs, Printed Circuits Handbook, (4thed., McGraw Hill); and T. Kiko, Printed Circuit Board Basics (PMS Indus.).
After formation of the microvia or other aperture, electroless plating procedures are then used to form a first metallic coating over the substrate surfaces and electrolytic copper deposition is then used to enhance the thickness of the coating. Alternatively, electrolytic copper may be plated directly over a suitably prepared microvia as disclosed in any of U.S. Pat. Nos. 5,425,873; 5,207,888; and 4,919,768. The next step in the process comprises electroplating copper onto the thus prepared conductive microvias using an electroplating solution of the invention.
Plating baths of the invention are preferably employed at or above room temperature, e.g. up to and somewhat above 65xc2x0 C. The plating composition is preferably agitated during use such as by air sparger, work piece agitation, impingement or other suitable method. Plating is preferably conducted at a current ranging from 1 to 40 ASF depending upon substrate characteristics. Plating time may range from about 5 minutes to 1 hour or more, depending on the difficulty of the work piece. See generally the examples which follow for exemplary preferred procedures.
A wide variety of substrates may be plated with the compositions of the invention, as discussed above. The compositions of the invention are particularly useful to plate difficult work pieces, such as circuit board substrates with small diameter, high aspect ratio microvias and other apertures. The plating compositions of the invention also will be particularly useful for plating integrated circuit devices, such as formed semiconductor devices and the like. See the examples which follow for exemplary substrates plated in accordance with the invention.
As discussed above, aspect ratios of at least 4:1, having diameters of about 200 nm or smaller have been effectively copper plated with no defects (e.g. no voids or inclusions by ion beam examination) using plating solutions of the invention. Microvias with diameters below 150 nm, or even below about 100 nm, and aspect ratios of 5:1, 6:1, 7:1, 10:1 or greater, and even up to about 15:1 or greater can be effectively plated (e.g. no voids or inclusions by ion beam examination) using plating solutions of the invention.
All documents mentioned herein are fully incorporated herein by reference. The following non-limiting examples are illustrative of the invention.


Blends of novolaks and cyanates, such blends can be thermally hardened in a short time and without using a catalyst and have an excellent storage stability. The resins obtained by the blends can be used as binding agents in abradants or as chip coverings or printed circuit boards (PCB) in electronics.

The invention relates to blends of novolaks with cyanates and a process for their preparation.
In general, novolaks (phenol-formaldehyde poly-condensation products) can be cured thermally, namely both with and without catalysts. In order to ensure the dimensional stability of the cured components, they must generally be subjected to a post-cure treatment. In order to avoid warping, the parts have to be clamped in suitable moulds which means an additional expenditure for manufacturing.
The object of the invention was to prepare novolak blends which instead of having this disadvantage possess such dimensional stability already after short thermal curing that a free-standing conditioning is made possible.
It has been possible to achieve this object of the invention with the blends of novolaks with cyanates of the invention.
The blends are composed of a novolak of the general formula
wherein R1 is hydrogen or methyl and n is a number greater than or equal to 1 and a cyanate of the general formula
wherein R2 is methyl and m is a number greater than or equal to 1, and, optionally, one or more additional polymer(s), catalyst(s) and/or usual filler(s) or auxiliaries.
Novolaks of the general formula I, in particular those wherein R1xe2x95x90H, are commonly known oligomeric condensation products of phenols with formaldehyde, which are obtainable industrially in various grades and with various properties. They can be polymerized with and without additives. Suitable novolaks with R1=methyl (xe2x80x9ccresol novolaksxe2x80x9d) are, for example, available under the designation 371B from the company Borden Chemicals.
Cyanates of the general formula II are generally prepared by reacting the corresponding oligomeric phenols with cyanogen chloride in the presence of a tertiary amine on the industrial scale and are likewise available in various grades and with various properties. They can be polymerized with and without additives, too.
The compounds customarily employed in the processing on novolaks may be used as catalysts. These are known to those skilled in the art. Flame retardants or additives for improving the thermal conductivity or the mechanical or electrical properties of the cured resin may be added as fillers and auxiliaries, for example. These additives are also known to those skilled in the art.
In the blend of the invention, the cyanate fraction of the combined amount of cyanate (II) and novolak (I) is judiciously from 10 to 90% by weight and the novolak fraction judiciously from 90 to 10% by weight, corresponding to a weight ratio cyanate:novolak of 10:90 to 90:10.
In the production of the blends of the invention, the procedure in general is to mix the components physically. Mixing can, for example, take place in a suitable mill, for example in a vibrating mill; alternatively, the components can be melted together or combined with the aid of an appropriate solvent, in which latter case it is necessary to remove the solvent again.
The blends of the invention are thermally curable within a short time and are additionally notable for high long-term stability in the uncured state, as can be shown, for example, by the constant gel time.
A further advantage of the blends according to the invention is that the gel time and hence the curing cycle for the blend is considerably shorter than for the individual components of the blend. As a result, the use of catalysts becomes either completely superfluous, or can at least be reduced considerably.
The invention additionally provides the resin obtainable by thermal curing of the blend according to the invention.
The mixture is advantageously cured without a catalyst by heating it at a temperature from 100 to 300xc2x0 C., preferably from 150 to 250xc2x0 C., for a period of 1 to 15 minutes.
The resultant cured blends are notable for outstanding dimensional stability and can therefore be employed, for example, in binders for abrasives or in the electronics sector for chip encapsulations or printed circuit boards (PCBs)


In one embodiment, the present invention includes a method for allocating at least one dedicated core and at least one shareable core to a first partition of a system, where the cores are owned by the first partition. During operation, the shareable core(s) may be made dynamically available for use in one or more other partitions of the system, while the first partition retains ownership of the shared core(s). Other embodiments are described and claimed.

Embodiments of the present invention relate to processor-based systems, and more particularly to partitioned systems.
As computer systems become more complex and provide for greater processing capabilities, many systems are implemented in a partitioned fashion. That is, resources of the system are dedicated to separate partitions, where they are isolated from other partitions. Each partition may operate in its own context using various resources such as processors, memory, input/output (I/O) devices and the like. Furthermore, a dedicated operating system (OS) may be present in each partition.
Different types of partitioned systems exist. Certain systems are referred to hard partitioned systems, where hardware is replicated across the different partitions such that each partition includes its own independent hardware to independently perform tasks. Examples of such hard partitioned systems are various server-based systems for performing network processing functions, among other such activities. Other systems are so-called soft partitioned systems, where a single set of hardware exists that is controlled by centralized software such as a virtual machine monitor (VMM). The VMM owns the various hardware resources. In turn, multiple virtual machines (VM's) may operate as independent logical systems that believe they have full access to the underlying hardware, while in fact the VMM provides time-multiplexed or simulated access to the hardware by the different VMs.
In any of these partitioning paradigms, the actual hardware resources are owned by a single entity (e.g., a hard partition or centralized software such as an OS or VMM). As a result, the resources are dedicated to their owner and in cases where the resources are not fully utilized by their owner, underutilization can occur which can negatively affect performance of other partitions that are fully consuming their resources, as well as the overall system.

Sharing resources of a partitioned system


A near-infrared night vision device to which a pedestrian detection device is applied includes a near-infrared projector, a near-infrared camera, a display and an ECU. By executing programs, the ECU constitutes a pedestrian candidate extraction portion and a determination portion. The pedestrian candidate extraction portion extracts pedestrian candidate regions from near-infrared images. The determination portion normalizes the sizes and the brightnesses of the pedestrian candidates extracted by the pedestrian candidate extraction portion, and then computes the degrees of similarity between the normalized pedestrian candidates. The determination portion determines that a pedestrian candidate having two or more other pedestrian candidates whose degree of similarity with the pedestrian candidate is greater than or equal to a predetermined value is not a pedestrian.

1. Field of the Invention
The invention relates to a pedestrian detection device and a pedestrian detection method.
2. Description of the Related Art
In recent years, vehicular night vision devices which pick up and display near-infrared images of an area forward of a vehicle, and detect pedestrians from the picked-up images, and present results of the detection superimposed on the near-infrared images have been put into practical use. As a pedestrian detection technology for use in such a night vision device, Japanese Patent Application Publication No. 2005-352974 (JP-A-2005-352974) describes a technology that searches for whether or not a site in a detection object that is the same in shape as a predetermined site in the detection object continuously exists. If the site being the same in shape as the predetermined site continuously exists in the detection object, the technology determines that the object is an artifact, and excludes the object, and proceeds to recognize a pedestrian from the remaining detection objects.
On the other hand, in a real road environment, there relatively frequently occurs a situation in which a plurality of artifacts, for example, guardrail posts, utility poles, etc., exist side by side. In the case where such a plurality of artifacts are extracted as detection objects, that is, candidates for pedestrians, it is necessary in the foregoing technology to search on each of the pedestrian candidates for whether or not a site being the same in shape as a predetermined site continuously exists. To determine whether or not a pedestrian candidate is a pedestrian with respect to all the pedestrian candidates, the technology inevitably requires a long processing time, which is a problem. Therefore, a faster process of determining whether or not a pedestrian candidate is a pedestrian (a faster pedestrian detection process) is desired particularly in systems that require a real-time characteristic of the process, such as a system used in a vehicle that runs at high speed.

Pedestrian detection device and pedestrian detection method


An attachment structure system is disclosed for attaching a damper to a vehicle. The attachment structure system can include a stiffener body that has a central portion connected to a damper. The stiffener body can be connected to both the vehicle's frame and a vehicle body portion, such as the wheel housing, to reduce noise, vibration, and harshness from being transmitted to the driver of the vehicle, and to provide other structural and ride characteristic benefits to the vehicle.

1. Field
The disclosed subject matter relates to an attachment structure system configured to attach a damper to a vehicle and also relates to a method of using the attachment structure system. In particular, the disclosed subject matter relates to an attachment structure system that includes a stiffener component or body and used for securing a vertical damper in a vehicle. The longitudinal axis of the damper can intersect a central portion of the stiffener body.
2. Brief Description of the Related Art
Conventional vehicle damper attachment structure systems for vertically oriented dampers include a metal stiffener structure that has a longitudinal axis extending in the vertical orientation with respect to the vehicle. The longitudinal axis of the stiffener structure is offset in a direction spaced along the longitudinal axis of the vehicle from a longitudinal axis of the vehicle damper (e.g., shock absorber, strut, spring, etc.). Thus, additional attachment components are needed to attach the vehicle damper to the vehicle frame and/or wheel house body structure. Moreover, the conventional damper attachment structure system includes a stiffener structure that is welded to the vehicle frame and/or vehicle body and which has additional structures that attach to and offset the vehicle damper from the stiffener. The stiffener and other attachment components extend parallel to and are spaced from the vehicle damper. The offset nature of the vehicle damper relative to the stiffener structure and attachment components results in a certain amount of flex in the attachment structure system, which is often disadvantageous in terms of controlling noise, vibration, and harshness characteristics for the vehicle. In addition, the stiffener and other attachment components are attached at points in single shear, which is also not ideal.

Vehicle damper attachment structure system and method


The invention provides biopolymer sponge tubes closed at one end for use in surgery. The preferred biopolymer iscollagen. The biopolymer sponge tubes are prepared by forming an aqueous dispersion of the biopolymer, introducing the dispersion into tube-shaped moulds, freezing the dispersion in the moulds to form a shaped, aqueous dispersion, followed by freeze-drying the frozen aqueous dispersion. The tubes are fitted over endoscopic surgical staplers to provide improved sealing of stapled tissues, especially for air-tight sealing in lung resections.

The present invention relates to biopolymer sponge tubes and the use thereof in surgery.
Surgical staple guns are widely used in the haemostasis and subsequent sealing of tissue following surgical procedures. For example, in the sealing of tissue following lung volume reductions for patients with emphysema.
Typically, the linear surgical staplers have two separate barrels of differing dimensions, namely a staple cartridge and an anvil, which close together during the stapling. The Burdorff, U.S. Pat. No. 5,697,543 issued Dec. 16, 1997, the Bittner et al., U.S. Pat. No. 5,673,842 issued Oct. 7, 1997, and the Schulze et al., U.S. Pat. No. 5,065,929 issued Nov. 19, 1991, each of which are incorporated herein by reference, provide examples of surgical staplers.
Often surgical staplers are indicated for use with a buttressing material, such as bovine pericardium, which surgeons use to reinforce staple lines and prevent leaks. According to current surgical procedure, the pericardium is wrapped around the barrels of the stapler prior to use. In use, the two barrels of the staple gun are placed on either side of the tissue that requires sealing. The stapling action brings together the two barrels with the pericardium, which is stapled into position at the appropriate site. The pericardium then acts as a seal to prevent exudate/air leakage.
The use of bovine pericardium in the above stapling procedure suffers from the drawbacks of possible antigenicity of the bovine pericardium, and lack of control over the precise shape, configuration and thickness of the bovine pericardium.
It is known to use pledgets of material to achieve hemostasis along a staple line as shown in the Trumbell et al., U.S. Pat. No. 5,263,629, issued Nov. 23, 1998 and incorporated herein be reference. Trumbell et al. provide rectangular pledgets of a fabric-like material, preferably having hemostatic properties, between the anvil and the staple cartridge in a surgical stapler. Staples are fired through both the pledget and the tissue to adhere the pledget to the tissue along the staple line. Placement and retention of the pledgets in the stapler can be quite tricky.
It is known to provide collagen tubes by the extrusion of a collagen gel into a coagulating bath. Such tubes have been used in micro-surgery, and for vascular prostheses. Implanted collagen films and/or collagen sponges have been suggested as slow-release matrices for therapeutic agents. The properties and applications of collagen biomaterials have been reviewed by A. Huc in Journal of American Leather Chemists Association, Vol. 80, pages 195-212 (1985).
U.S. Pat. No. 3,157,524 describes forming porous collagen tubes by freezing an aqueous collagen slurry in a tubular mold, followed by solvent drying in an anhydrous isopropanol bath.
Alternatively, the slurry may be frozen onto the outside of a tube through which a suitable refrigerant is passed, followed by solvent drying. The sponges are said to control bleeding in surgery through the application of pressure and coagulating material such as thrombin. No specific applications are disclosed.
It has now been found that biopolymer sponge tubes are highly suitable for replacing bovine pericardium and rectangular pledgets in the surgical stapling procedure described above.
Accordingly, the present invention provides a biopolymer sponge tube closed at one end.
The biopolymer sponge tube is closed at one end to enable it to be fitted over a barrel of a staple gun without sliding too far along the barrel.
The present invention also provides a surgical stapler comprising a staple cartridge and an anvil, and having a biopolymer sponge tube (which need not be closed at one end) fitted over the staple cartridge and/or over the anvil. Preferably, biopolymer sponge tubes are fitted over each of the staple cartridge and the anvil. Preferably, the biopolymer sponge tube or tubes are closed at one end.
The present invention further provides the use of a biopolymer sponge tube for the preparation of a surgical stapler as above for use in surgery.
The biopolymer used to make the sponge tubes may be any biocompatible and bioabsorbable polymer. Preferably, the biopolymer is selected from the group consisting of structural proteins, cellulose derivatives (including oxidised regenerated cellulose), starch derivatives, chitin, chitosan, glycosaminoglycans, and mixtures thereof. Preferred structural proteins include gelatin, all collagen types, keratin, laminin, fibrin or fibronectin. The phrase xe2x80x9call collagen typesxe2x80x9d encompasses type I and type II collagen, atelocollagen and other modified collagens. Suitable cellulose derivatives include carboxymethyl cellulose and hydroxyethyl cellulose, in addition to oxidised regenerated cellulose. Suitable alginates include sodium alginate, calcium alginate and mixtures thereof. Suitable glycosaminoglycans include hyaluronic acid, chondroitin sulphate, heparin and heparan sulphate.
The biopolymer sponge tube may be reinforced by a biopolymer matrix, such as a Vicryl (registered trade mark) polylactide/polyglycolide mesh. However, preferably, the biopolymer sponge is not reinforced.
Preferably, the biopolymer sponge tube consists essentially of one of more collagen types. The collagen may be chemically cross-linked to modify its physical properties and rate of resorption in vivo. Collagen is the preferred biopolymer because of its easy availability, low cost, low antigenicity, and well-understood properties, which enable the collagen sponge to be prepared with controlled physical and biological behaviour.
The biopolymer sponge tube is preferably sterile. Preferably, the biopolymer sponge tube comprises less than 10% by weight of water to enable it to be stored indefinitely without decomposition. The biopolymer sponge tube preferably further comprises a therapeutic compound selected from the group consisting of antiseptics, such as chlorhexidine, antibiotics such as streptomycin, analgesics such as ibuprofen, steroids, cell growth factors and wound healing factors. Preferably, the therapeutic compound is present in amount of 0.01% to 2% by weight, based on the weight of the biopolymer sponge tube.
Preferably, the biopolymer sponge tube is fully bioabsorbable in the mammalian body. This makes it especially suitable for use in conjunction with surgical stapling procedures, especially in endoscopic surgery. The rate of bioabsorption of the biopolymer can be controlled by cross-linking the biopolymer.
The biopolymer sponge tubes according to the present invention preferably have substantially uniform internal and external cross-sections. Preferably, the wall thickness of the tubes is also substantially constant.
Preferably, the internal and external cross-sections are both substantially circular or rectangular. Preferably, the average internal diameter of the biopolymer sponge tubes is from 3 mm to 30 mm, or preferably 5 mm to 20 mm, and the wall of the biopolymer sponge tube has a substantially uniform uncompressed wall thickness in the range of 1 to 4 mm. Preferably, the ratio of the length to the average external diameter of the biopolymer sponge tubes is in the range of 2:1 to 10:1, preferably 3:1 to 5:1. These preferred shapes and dimensions are especially suitable for fitting the biopolymer sponge tube over one or other barrel of a surgical stapler.
The biopolymer sponge tubes for use in the present invention are preferably prepared by a process comprising: providing an aqueous dispersion of the biopolymer; introducing the dispersion into a tube-shaped mold, following by freezing the dispersion to provide a shaped frozen dispersion; and freeze-drying or solvent-drying the shaped frozen dispersion to form the biopolymer sponge tube.
Preferably, the aqueous dispersion comprises 0.05-2.5% w/v of the biopolymer. The aqueous dispersion may be buffered to an optimum pH, and may also comprise therapeutic active agents for incorporation into the final biopolymer sponge tube. The aqueous dispersion may also contain emulsified lipid droplets for incorporation into the biopolymer sponge tube, as described and claimed in our patent application EP-A-0567234, and its U.S. equivalent, U.S. Pat. No. 5,660,857 issued Aug. 26, 1997 which is incorporated herein by reference, and which provide several benefits including enhancing liquid impermeability of the resulting collagen product.
A chemical cross-linking agent, such as glutaraldehyde or hexamethylene diisocyanate (HMDI) may be incorporated in the aqueous dispersion, or may be used to treat the biopolymer sponge tube following the drying step.
The tube-shaped mold is preferably in the shape of a tube closed at one end. If it is intended that the final biopolymer sponge tube should be reinforced with a bioabsorable mesh, such as a Vicryl(trademark) (registered trade mark) polylactide-polyglycolide mesh, then the mesh is inserted into the mold with the aqueous dispersion prior to freezing.
Preferably, the frozen aqueous dispersion is removed from the mold prior to drying. This can be achieved by warming the mold slightly and inverting the mold to allow the frozen aqueous dispersion to drop from the mold. Preferably, the central part of the mold defining the inside wall of the tubular frozen aqueous dispersion can be warmed and removed from the mold automatically. More preferably, the end (i.e. base wall) of the mold is moveable in piston fashion along the length of the mold to expel the frozen aqueous dispersion from the mold.
Preferably, an array of tube-shaped molds is provided for simultaneous molding and freezing of a plurality of frozen aqueous dispersions. More preferably, the steps of pouring the aqueous dispersion into the mold, freezing, and expelling the frozen aqueous dispersion from the mold are alternated.
The shaped frozen dispersion is freeze-dried or solvent-dried to form the biopolymer sponge tube. Freeze-drying is typically carried out at xe2x88x9210xc2x0 C. to +20xc2x0 C. overnight. Solvent drying is preferably carried out in a succession of baths of anhydrous isopropyl alcohol as described in U.S. Pat. No. 3,157,524, the entire content of which is expressly incorporated herein by reference.
The dried biopolymer sponge tube is preferably packaged in aseptic packaging, and then dry sterilised, preferably by gamma-irradiation.

Methods for making biopolymer sponge tubes


A contact for a semiconductor device has a via extending through a dielectric and collimated titanium in the via. Depositing titanium by collimation places sufficient metal into high aspect ratio contacts to make good electrical connection. The collimated titanium may be reacted in a nitrogen containing ambient to form a titanium silicide layer at the bottom of the contact and a titanium nitride layer over the titanium silicide layer. The titanium silicide layer provides good electrical contact to a device in a silicon semiconductor substrate and lowers contact resistance. Tungsten may be deposited over the colliminated titanium to form a conductor layer. The titanium nitride layer provides a sticking layer for the tungsten. The contact structure and the method are useful in high aspect ratio contacts present in VLSI multilevel interconnected devices such as dynamic random access memories.

The quest to develop larger and larger semiconductors of the dynamic random access memory (DRAM) type is a well-known goal. The industry has steadily progressed from DRAMs of the 16K type, shown in U.S. Pat. No. 4,081,701 issued to White, McAdams and Redwine, and the 64K type, shown in U.S. Pat. No. 4,055,444 issued to Rao, to DRAMs of the 1M type, as described in U.S. Pat. No. 4,658,377 issued to McElroy. DRAMs of the 4M type are now being produced. Production plans for 16M DRAMs of submicron technology now exist and experimentation of 64M DRAMs has begun. One factor furthering the development of larger DRAMs is the reduction in memory cell geometries as illustrated in U.S. Pat. No. 4,240,092 to Kuo (a planar capacitor cell), and as illustrated in U.S. Pat. No. 4,721,987 to Baglee et al, (a trench capacitor cell).
One difficulty in fabricating high density integrated circuit structures such as DRAMs is filling the contact holes, or vias, with metal so that electrical contact may be made to the integrated circuits. U.S. Pat. No. 4,673,592 to Porter et al. discusses this difficulty and describes a metal planarization process to reliably fill deep depressions having high aspect ratios. In order to minimize space, the aspect ratios of contacts become even higher as memory cell geometries continue to decrease. It becomes even more difficult to fill these high aspect ratio contacts with conductive material.
It is thus an object of this invention to provide a method for packing high aspect ratio via contacts with metal. It is also an object of this invention to provide an improved contact structure.
Other objects and advantages of this invention will be apparent to those of ordinary skill in the art having reference to the following specification and drawings.

Metallization process for a semiconductor device


A beverage containing a mixed sodium potassium polyphosphate glass with a high potassium to sodium ratio and a low level of insoluble material is provided. The mixed sodium-potassium polyphosphate glass has the formula (K,Na)(n+2)O(PO3)n, and contains less than 10% by weight insoluble material. These materials are effective in controlling yeast, mold, and bacterial growth. The beverage comprises about 100 ppm to about 3000 ppm of a polyphosphate.

This invention relates to polyphosphates and to methods for their preparation. In particular, this invention relates to polyphosphates with a high potassium to sodium ratio, which are useful in the preparation of low sodium beverages as well as meat and other food products in which sodium reduction is desired.
Many beverages provide an excellent environment for rapid microbial growth because microorganisms can rapidly proliferate by feeding on nutrients present in the beverage. Fruit juice, for example, an important component of many beverages, provides an excellent medium for the growth of microorganisms. Consequently, controlling microbial growth in packaged beverages, especially those that are stored under ambient conditions, is an ongoing concern among beverage manufacturers.
Although beverages can be maintained under ambient conditions if they are heat pasteurized during packaging (hot packing) or are packaged under completely aseptic conditions (aseptic packaging), not all beverages can packaged by these methods. Hot packing, which involves heating the beverage and its container to a temperature between about 85-105xc2x0 C. during packaging so that the resulting sealed beverage contains no food spoilage microorganism, is unsuitable for manufacturing certain types of beverages. Hot packaging is commonly used in the manufacture of beverages that are canned or bottled in glass containers, but flexible containers made from high density polyethylene, for example, cannot be subjected to the temperatures used during hot packing operations. Although packaging under completely aseptic conditions produces a beverage free of food spoilage microorganisms, aseptic packaging methods are often unsuitable for manufacturing beverages packaged in certain beverage containers, e.g., rigid containers such as glass and cans.
In addition, a sterile environment is difficult to maintain during the packaging operation. Frequent cleaning of the packaging line, which is time consuming, expensive, and frequently ineffective in preventing microbial contamination, is necessary.
Because these methods cannot be used for all types of beverages and because these methods sometimes do not produce a beverage that is free of microorganisms, preservatives, such as sorbates, benzoates, and organic acids, are often added to inhibit microbial proliferation.
However, when used at the levels necessary to inhibit subsequent microbial proliferation at ambient temperatures, preservatives often contribute an off-flavor to the beverages. But, when used at concentrations sufficiently low to avoid an off-flavor, preservatives are generally unable to effectively inhibit the growth of many food spoilage microorganisms.
Sodium salts of phosphoric acid derivatives, especially food grade sodium hexametaphosphate, have been used with preservatives to enhance the potency of preservatives so that lower levels can be used, thus improving taste. Calderas, U.S. Pat. No. 5,431,940, incorporated herein by reference, for example, discloses the use of polyphosphates in combination with sorbate preservatives in dilute juice beverages having relatively low water hardness.
However, addition of sodium salts to beverages increases their sodium content and makes them unacceptable to users who require a low sodium beverage. Commercially available potassium polyphosphate salts, often collectively referred to as xe2x80x9cpotassium Kurrol""s salt,xe2x80x9d are highly polymerized, crystalline polyphosphates, typically containing 400 to 20,000 polyphosphates units. Although these materials contain high levels of potassium, they are not acceptable for beverage applications because they contain large amounts of insoluble material. Thus, a need exists for polyphosphate salts that contain a high potassium to sodium ratio and a low level of insoluble material and are effective in controlling microorganisms.
In one embodiment the invention, a beverage containing a mixed sodium potassium polyphosphate glass with a high potassium to sodium ratio and a low level of insoluble material is provided. The mixed sodium-potassium polyphosphate glass has the formula (K,Na)(n+2)O(PO3)n, and contains less than 10% by weight insoluble material. These materials are effective in controlling yeast and mold growth. The beverage comprises about 100 ppm to about 3000 ppm of a polyphosphate.
Long chain polyphosphates in which the sodium to potassium ratio is 0.5 to 3.8 and in which n is greater than 10 are effective in controlling microorganisms and have sufficient solubility to be useful in beverage applications. These materials can be used to decrease sodium content of beverages, making them more acceptable to users who require a low sodium beverage.
In the following description xe2x80x9cMxe2x80x9d represents potassium, sodium, or a mixture of potassium and sodium. (K,Na) represents a mixture of potassium and sodium. Those skilled in the art will recognize that in phosphate salts these components are mono-positively charged ions. For example, MH2PO4 represents monopotassium phosphate (KH2PO4), monosodium phosphate NaH2PO4), or a mixture of these materials; and MOH represents potassium hydroxide, sodium hydroxide, or a mixture of these materials, i.e., (K,Na)OH.
The polyphosphate has the following composition:
(K,Na)(n+2)O(PO3)nxe2x80x83xe2x80x83(I)
the ratio of potassium to sodium is about 0.5 to 3.8, preferably 1.0 to 3.8, more preferably 2.4 to 3.6;
the average value of n is greater than 10; and
at least 85% of the phosphate species comprise more than three phosphate units.
The polyphosphate contains less than 10% by weight, preferably less than 5% by weight, a material that is insoluble in aqueous solution (i.e., material that is not soluble in cold water). A 1% solution of the polyphosphate in water has a pH of about 7.0 to about 7.2. X-ray analysis indicates that the polyphosphate is amorphous. In dilute aqueous solution (1%) the polyphosphate is as stable to hydrolytic degradation as sodium polyphosphate.
The ratio of potassium to sodium is about 0.5 to 3.8, preferably 1.0 to 3.8, and more preferably 2.4 to 3.6. Above a potassium to sodium ratio of 3.8, excess insolubles, which make the material unacceptable for use in beverage applications, are present.
The average number of polyphosphate units, n, is greater than 10, preferably greater than 12, and up to about 100.
Preparation of aqueous solutions of mixed polyphosphates by ion exchange is described in Iler, U.S. Pat. No. 2,557,109. However, this process produces an aqueous solution, not a glassy solid.
The glassy mixed polyphosphate of this invention can be prepared by the following reaction:
A mixture of monopotassium, phosphate, monosodium phosphate, and potassium and/or sodium hydroxide is prepared. The potassium/sodium ratio of the mixture should be the same ratio that is desired in the glassy polyphosphate product. Preferably, no ions other than sodium, potassium, the ions derived from phosphate (i.e., H2PO4xe2x88x92, HPO4xe2x88x922, PO4xe2x88x923), and optionally, hydroxide, are present. If desired, water may also be added to the mixture. For the preparation of polyphosphates for use in beverage applications, food grade materials are preferred.
The (K,Na)/P ratio should be between 1.0 and 1.6, and is adjusted for the desired value of n. The smaller the value of this ratio, i.e. the closer this value is to 1.00, the higher the average value of n.
As will be obvious to those skilled in the art, a mixture containing the appropriate amounts of potassium ions, sodium ions, and phosphate ions can be obtained by partially or completely replacing one or more of these components with other materials, such as phosphoric acid, dipotassium phosphate, disodium phosphate, tripotassium phosphate, trisodium phosphate, etc. Phosphoric acid in which the phosphate is already partially polymerized, i.e., 115% phosphoric acid, etc., may also be used. For example, an appropriate mixture could be prepared from monopotassium phosphate, monosodium phosphate, and dipotassium phosphate; from phosphoric acid, sodium hydroxide, and potassium hydroxide; etc. Partially polymerized phosphates, i.e., pyrophosphates and higher phosphates may also be used as starting materials, but are not preferred. All these methods are equivalent methods of forming the mixture described above.
The mixture is placed in a vessel that can withstand the heating conditions, such as a ceramic or alumina vessel, and heated in an appropriate apparatus, such as a muffle furnace. On an industrial scale, the process may be carried out in a bigger furnace, e.g., 8 feet (about 2.4 M) wide by 15 feet (about 4.6 M) long, lined with zircon ramming mix on the bottom designed to withstand a melt temperature of at least 800xc2x0 C.
The mixture is heated at about 750xc2x0 C. to drive off water and to form a clear melt. Heating below 600xc2x0 C. produces materials with insufficient long-chain (n greater than 3) phosphate species. Heating at 780xc2x0 C. produces material that contains excessive insolubles or difficultly-soluble material that is unacceptable for beverage applications. Heating should be carried out for about 0.75 to about 1.5 hr. Heating to the required temperature can be carried out in one step or in several stages. After heating, the reaction mixture containing the polyphosphate is, preferably, rapidly cooled so that no crystal growth occurs.
The product is a mixed sodium-potassium polyphosphate glass of formula (K,Na)(n+2)O(PO3)n. The polyphosphate glass contains less than 10% by weight insoluble material.
The preparation of beverages and the materials used therein is well known to those skilled in the art and has been described in numerous patents and publications, such as, Nakel, U.S. Pat. No. 4,737,375, which emphasizes the preparation of carbonated beverages; Calderas, U.S. Pat. No. 5,431,940, and Pflaumer, U.S. Pat. No. 5,641,532, both of which emphasize the preparation of non-carbonated juice beverages. All three of these patents are incorporated herein by reference.
Beverages can be prepared by making a beverage concentrate, adding to it a sugar syrup containing the polyphosphate of this invention, including the acidulants, preservatives, and water in amounts sufficient to obtain the desired beverage composition. The concentrate is prepared by admixing a dispersion of the flavor oil in ester gum and a dispersion of a hydrocolloid such as gum acacia in water, then homogenizing to form a stable emulsion of the flavor oil. Aside from providing the desired flavor, this emulsion also serves to add opacity and texture to the beverage. Other suitable oils may be added to the concentrate to increase opacity. Preservatives, acidulants, and coloring material may also be added to the concentrate. The sugar syrup is prepared separately by mixing sugar syrup such as high fructose corn syrup with water, then adding to it any optional water soluble vitamins, the polyphosphate, acidulants, and preservatives. The sugar syrup and concentrate are combined to form a non-carbonated beverage. It can then be packaged and stored.
Polyphosphates are effective in inhibiting the growth of microorganisms in non-carbonated beverages when present in the beverage at about 100 ppm to about 3000 ppm, typically about 300 ppm to 3000 ppm, preferably about 500 ppm to about 1500 ppm, and more preferably about 1000 ppm.
Non-carbonated beverages may comprise 0.1 to 40%, preferably 1 to 20%, and more preferably 2% to 10%, and most preferably 3% to 6% fruit juice (weight percentage based on single strength 1-16xc2x0 Brix fruit juice). The juice may be any citrus juice, non-citrus juice, or a mixture thereof, which is known for use in non-carbonated beverage. Non-fruit juices, such as vegetable or botanical juices, and tea solids also can be used in non-carbonated beverages. When tea solids are used, the non-carbonated beverage typically comprises preferably about 0.02 to about 0.25%, more preferably about 0.07% to about 0.15%, by weight of tea solids. The term xe2x80x9ctea solidsxe2x80x9d as used herein means solids extracted from tea materials including those materials obtained from the genus Camellia, including C. sinensis and C. assaimica.
Non-carbonated beverages have a pH of from about 2.5 to about 4.5, preferably from about 2.7 to about 4.0. This pH range is typical for non-carbonated dilute juice beverage products. Beverage acidity can be adjusted to and maintained within the requisite range by known and conventional methods, e.g., the use of food grade acid buffers. Typically, beverage acidity is a balance between maximum acidity for microbial inhibition and optimum acidity for the desired beverage flavor and sourness impression.
Non-carbonated beverages typically contain an artificial or natural, caloric or noncaloric, sweetener. Preferred are carbohydrate sweeteners, more preferably mono- and or disaccharide sugars, such as maltose, sucrose, glucose, fructose, invert sugars and mixtures thereof. The non-carbonated beverage products typically comprise from about 0.1% to about 20%, more preferably from about 6% to about 14%, sugar solids by weight of the beverage products. Optional artificial or noncaloric sweeteners include, for example, saccharin, cyclamates, acetosulfam, L-aspartyl-L-phenylalanine lower alkyl ester sweeteners (e.g., aspartame), and the like. The sweetener can be provided to some extent by the other components, such as the fruit juice.
Non-carbonated beverages may also comprise any other ingredient or ingredients typically used as optional beverage ingredients, such as flavorants, preservatives (e.g., organic acids), colorants and so forth. Preservatives commonly used in beverage products include, for example, sorbates, benzoates, organic acids, and combinations thereof. Preferred preservatives are sorbic acid, benzoic acid, alkali metal salts thereof, and mixtures thereof. Typically about 400 ppm to about 1000 ppm, more typically about 650 ppm to about 750 ppm, of preservative is added to the beverage, but use of the antimicrobial long chain polyphosphate of this invention in the beverage will allow this amount to be reduced.
Non-carbonated beverages may contain up to 110% of the U.S. Recommended Daily Allowance (RDA) of vitamins and minerals, provided that such vitamins and minerals are chemically and physically compatible with the essential elements of the non-carbonated beverage products and do not cause the growth of microorganisms. Preferred are vitamin A, provitamins thereof (e.g., xcex2-carotene), and ascorbic acid. However, calcium, iron and magnesium fortification should be avoided since these polyvalent cations can bind to and inactive the polyphosphates. Gums, emulsifiers and oils, such as guar gum, xanthan, alginates, mono- and di-glycerides, lecithin, pectin, pulp, cottonseed oil, vegetable oil, food starches, and weighting oils/agents, as well as esters and other flavor and essence oils may also be included.
The balance of the beverage is added water. Added water does not include the water incidentally included in the beverage by other added materials, such as fruit juice or sugar syrup. Although the high potassium polyphosphate of this invention can be used with added water of any hardness typically used to prepare beverages, the added water typically comprises 0 to about 180 ppm hardness.
Phosphates, such as sodium tripolyphosphate, are added to meat, poultry, and seafood to improve its functional properties, particularly its moisture retention. In addition, this prevents a decrease in nutritional value by retaining soluble proteins, minerals, and vitamins. Glassy sodium polyphosphates, also known as sodium hexametaphosphates, are commonly used with sodium tripolyphosphate for the preparation of various muscle foods such as ham, bacon, and luncheon meats. Muscle foods refers to meat products derived primarily from the animal muscle (bovine, porcine, or seafood).
In the preparation of these muscle foods, the common method is to prepare a brine or pickle comprising water, salt (i.e., sodium chloride), 1% to 5% by weight phosphate, and optionally, ingredients such as nitrite or nitrate if the food is a cured product; carbohydrates in the form of, such as, corn syrup solids, dextrose, or sucrose; gums or starches, such as carrageenan, corn starch, potato starch; and proteins, such as soy isolates or concentrates. Typically, about 10% to 50% by weight of brine solution, based on the weight of the muscle food before addition of the brine solution, is added to the muscle food.
It is recommended that the phosphate be dissolved in the water first. Salt is usually added after the phosphate is completely dissolved, followed by the rest of the ingredients. After the brine or pickle is prepared, it is generally cooled to about 40xc2x0 F. (about 4xc2x0 C.) or lower before being introduced to the muscle. Typically, the concentration of salt in the brine is adjusted so that the concentration of salt in the final muscle food product will be about 0.8% to about 2.5% by weight. Introduction to the muscle may be achieved either through injection machines or by mixing directly with the muscle in a tumbler or mixer.
In the process of cooling the brine or pickle, salt and phosphates may precipitate out if the brine or pickle is especially concentrated and if the water used has a high level of hardness. Similarly, storing the brine or pickle at room temperature over an extended period of time can trigger premature precipitation of the salt or phosphate. The addition of the glassy sodium polyphosphate to the brine or pickle either by itself or as one of the components of a phosphate blend ensures that the brine or pickle does not precipitate prior to being added to the muscle. High potassium polyphosphate can be used in place of the sodium polyphosphate to reduce the amount of sodium added with the phosphate. Various levels of brines or pickles may be added to the muscle, however, for the purpose of keeping brines stable, 0.1% to 0.5% by weight polyphosphate with a chain length greater than or equal to 6 is required in the brine. Alternatively, the phosphate may be a polyphosphate of formula I above.
The high potassium polyphosphate can be used to produce a reduced sodium food in any other food application in which phosphates are normally used. These applications include, for example: imitation dairy products, such as non-dairy creamers, whipped toppings, and frozen desserts; dairy products, such as milk, cream, cheese, whey, and ice cream; egg whites; dried and canned fruit; jellies and jams; and gums, such as carrageenan. Food applications of polyphosphates are summarized below.
The high potassium polyphosphate can be used in beverages, especially in low sodium beverages as well as in isotonic beverages. In addition, it can be used to produce a reduced sodium food in any other food application in which phosphates are normally used.
The advantageous properties of this invention can be observed by reference to the following examples, which illustrate, but do not limit, the invention.
Throughout this specification and claims, all parts and percentages are by weight unless otherwise indicated.

Beverages containing mixed sodium-potassium polyphosphates


A method to display with combined color multiple quantitative images of tissue parameters obtained with nuclear magnetic resonance. The method allows an increased diagnostic accuracy, a higher sensitivity to pathologies of small extent, a standardization of acquisition sequences and a shortening of the total line required for performing the examination to be realized.

This invention relates to a method to display with combined color quantitative images of tissue parameters obtained with nuclear magnetic resonance (quantitative magnetic color imaging, QMCI).
More particularly, this invention relates to a method to synthetically represent tissue parameters by means of pseudonatural color images to be employed with nuclear magnetic resonance.
The documents mentioned herein with a reference numeral are listed at the end of this disclosure.
Nuclear magnetic resonance (NMR) or magnetic resonance imaging (MRI) is largely employed for tissue investigations for diagnostic purposes (1).
The signal obtained in spin-echo sequences, which are those most commonly employed in NMR, is given by the function:
1) S=KN(H)[1-e.sup.-TR/T1 (2e.sup.TE/2T1 -1)]e.sup.-TE/T2
wherein: by the symbol S=spin-echo signal in the NMR acquisition sequences are meant, said sequences consisting in the repetition of a set of two radiofrequency pulses, which are called the 90.degree. and 180.degree. pulses, the set being characterized by the time of repetition TR equal to the interval between the 90.degree. pulses and by the time of echo TE which is equal to twice the distance between the 90.degree. and the 180.degree. pulse, that generates a NMR signal which is called the echo at an interval TE from the 90.degree. pulse; T1 and T2 are the longitudinal and transverse relaxation times which are characteristic for the voxel of the tissue to be analyzed, N(H) is the number of the hydrogen atoms, TR and TE are the repetition time and the echo time respectively that characterize the sequence of pulses which is employed for the acquisition of the image, K is an efficiency constant that varies with the experimental conditions. The voxel is the volume element that contributes to the formation of the image element.
The expression 1) does not take into account second-order effects such as diffusion, chemical shift etc. The NMR image is thus not like the X-ray computerized tomography (CT), a map of one only physical parameter (e.g. the electronic density), but it is a function of a number of parameters that characterize the tissue under examination. The main parameters among those mentioned above are the T1 and the T2. The proton density, which is a signal multiplication factor, in most soft tissues has an almost constant value, so that it is not a significative parameter as far as the tissue characterization is concerned.
Users of such methodologies, in order to formulate a diagnosis, carry out at present a number of acquisition sequences of said tissues varying the TR and the TE so as to obtain a number of images with different weights of T1 and T2. Thus a global evaluation is performed of such parameters or of parameters depending on them. Such evaluation is not absolute, but it is relative to reference tissues such as fatty parts, muscles, the brain parenchyma, the cerebrospinal fluid, and so on. The remainder of the diagnostic information comes from the morphology of the observed tissues. Moreover, it is to be remarked from the expression 1) that in the NMR image the T2 gives a direct contribution to the formation of the signal, whereas the T1 gives an inverse contribution. Accordingly, with the same values of T1, tissues having a longer T2 show brighter than tissues having a shorter T2, whereas with the same values of T2, tissues having a longer T1 show darker than those having a shorter T1. Such king of representation which is that usually employed in the present NMR technology is not necessarily the best one from the diagnostic standpoint.
Methods for the production of color images as applied also to magnetic resonance are disclosed in the technical literature, but in many cases the images employed are those of the MR signal (2-5). In order to modulate with different information the chromatic components of color images, different acquisition sequences are employed. The results are not much reproducible, and in addition they are difficult to interpret and of poor iconographic quality.
Setting forth in advance that by the term pixel it is to be understood the image element, i.e. the matrix element which is represented in the form of an image, it is possible to calculate pixel by pixel the value of T2 (6) from a multiecho sequence (the TR value is constant while a number of images with different TE values is obtained), so obtaining an image of that parameter. In the same way, carrying out two sequences at equal TE but with different TR, it is possible to obtain an image of T1 by numerical computation. Such images, which are available on almost all commercial tomographic devices for MRI, are not much employed because of the following reasons:
1) the type of representation that stems from them is somewhat unnatural, as it is inverted with respect to the anatomic representation of the magnetic resonance signal;
2) the distribution of the values of the parameters lowers the contrast between some tissues whereas it amplifies such contrast for other ones to a large extant;
3) images show somewhat noisy in the background zones so that they are of poor iconographic quality.
The employment of parametric images or maps of a parameter is quite common in "Diagnostic Imaging" though the clinical applications are rare. The maps of the longitudinal and transverse relaxation times T1 and T2 are rarely employed in magnetic resonance techniques, but many commercial types of tomographic apparatuses are supplied with programs for their production.
Three prior art documents disclose methods for simultaneous display of relaxation times (T1 and T2) with color images: Kuhn M. H. and Menhardt W. (7) describe a method wherein color images are obtained by superimposing monochromatic (green, red and blue) parameter images of T1, T2 and proton density; Kamman R. L. et al. (8) describe a method wherein the color, defined as hue and saturation, of each pixel is computed from T1 and T2 using an algoritm based on a reference color triangle, and wherein the luminance is modulated by proton density; U.S. Pat. No. 4,789,831, describes a method wherein the magnetic resonance spin echo intensity is used to modulate the intensity of each pixel, and either T1 or T2 are used to define hue and saturation. As stated above, a poor iconographic quality is obtained where said parameters are used. The relaxation rates R1 and R2, which are defined respectively as VT1 and VT2, have never been employed, and no parameteric images have been produced for clinical purposes.
Bibliographic references known to the Author include:
1. Morris P. G. Nuclear Magnetic Resonance Imaging in Medicine and Biology, Clarendon Press, Oxford (1986).
2. Weiss K. L. et al. American J. Radiol, 149, 825-829 (1987).
3. Vannier M. W. and Douglas R. Current Concepts 24, 88-91 (1989).
4. Vannier M. W. et al. CRC Critical Rev. in Biomed. Engineering 15, 117-144 (1987).
5. Wells M. G. et al. Med. Biol. Eng. Comput. 27, 277-280 (1989).
6. Romano F. et al. XIV Congress Europ. Society of Neuroradiology, Udine Italy (1987).
7. M. H. Kuhn and W. Menhardt, Interactive MR Image Synethesis, Philips Tech. Rev. 43, No. 4,95-103, Feb. 1987.
8. R. L. Kamman, G. Stomp, H. J. C. Berendesen, Unified Multiple-Feature Color Display for MR Images, Magnetic Resonance in Medicine), 240-253 (1989).
Such parametric images have on the contrary a diagnostic validity which results in the advantageous substitution of them for the signal images on whose basis the diagnosis is formulated at present.
The Author of this invention has found how to exploit the intrinsic multiparametric character of the magnetic resonance signal, as well as how to exploit some features of color perception, and in particular the property according to which all colors can be obtained from suitable combination of red, green and blue light and, apart from saturation phenomena, two colors obtained by summing combinations of intensities of the three chromatic components are distinguishable if at least one chromatic component has a distinguishable intensity in the two combinations. Accordingly, color allows two or three different monochromatic images of different colors to be represented simultaneously, with no information loss, by simply overlapping such images, or otherwise by projecting them simultaneously on the same screen (a videoprojector or a color monitor with RGB colorimetric coding).
As the main parameters that characterize the tissue can be obtained from the common magnetic resonance techniques, a chromatic characterization of the tissues is obtained through the association of the intensity of a chromatic component to the value of each parameter and overlapping the components pixel by pixel. The result consists of a single image in which the tissues can be recognized by their "magnetic color", besides their own shape. It is evident that the result also depends on the physical parameters represented. The Author has checked various parameters and he has found that not only the longitudinal and the transverse relaxation rates supply parametric images of anatomic type, with "diagnostic" distribution of the contrasts and with very low noise, but the employment of the red and chromatic component for the longitudinal relaxation constant and of the green (or, better, the green+blue) chromatic component for the transverse relaxation constant gives images with almost natural color of the various tissues, and hence images of rapid and easy interpretation even for unskilled personnel. The technique can also be extended to three parameters, as for instance the proton density or other parameters that can be obtained from MRI (flow, diffusion, perfusion and so on) can be represented by the blue chromatic component.
Moreover, quantitative digital images can be obtained by such procedure which, compared to a two-dimensional chromatic scale supply the chromatic characterization of tissues while, through direct reading on regions of interest, they supply the values of the longitudinal and the transverse relaxation rates (and hence of the times T1 and T2 ) of the tissues so visualized.
The synthetic representation of NMR information avoids a complex and inaccurate mental evaluation on the user's side, such evaluation consisting in estimating, from the various images of the same section, the tissue parameters of a determined tissue, which is identified by shape, position or different intensity with respect to the tissues around the same. Once such parameters have been evaluated, the corresponding tissue type can be determined. By means of the process which is the object of this invention, the association in question is just the color-tissue association, while the values of the relaxation parameters can be read directly on the image shown on the monitor by means of a standard reading technique through a cursor or the definition of a region of interest.
Accordingly, it is possible to obtain:
a better diagnostic accuracy, because the calculation of the tissue parameters if extremely more precise than the subjective evaluation performed by the user, and because it is possible to distinguish tissues with very small differencies in the relaxation constants;
an increased sensitivity to small pathologies. Indeed, some small zones of altered signal quite often are not noticed in black-and-white images or they are mistaken for acquisition artifacts. On the contrary, in the chromatic reconstruction, the evidence of the characteristic color attracts the attention of the user even to very small anomalies;
a standardization of the acquisition sequences and a reduction in the total time required for performing the examination.
Indeed, the acquisition sequences are chosen at present from time to time according to the suspected pathology in order to increase the contrast between the pathological tissues and those around the same. By means of the chromatic technique, the acquisition sequences can be standardized in order to optimize the color image in terms of signal/noise ratio. The decision times required at present between an acquisition sequence and the next one are thus shortened.
Accordingly, it is an object of this invention a method for representing tissue parameters in nuclear magnetic resonance (NMR), said method comprising a synthetic representation step of said parameters by means of combined color images. Preferably, said synthetic representation comprises the step of overlapping at least two images obtained with different and independent chromatic scales.

Method to display with combined color multiple quantitative images of tissue parameters obtained with nuclear magnetic resonance