The present invention provides compositions comprising methylnaltrexone or a salt thereof, and compositions and formulations thereof, for oral administration.

Opioids are widely used in treating patients with pain. Such patients include those with advanced cancers and other terminal diseases and also those with chronic non-malignant pain and acute non-malignant pain. Opioids are narcotic medications that activate opioid receptors located in the central nervous system to relieve pain. Opioids, however, also react with receptors outside of the central nervous system, resulting in side effects including constipation, nausea, vomiting, urinary retention, and severe itching. Notable are the effects of opioids in the gastrointestinal (GI) tract where these drugs inhibit gastric emptying and peristalsis in the intestines, thereby decreasing the rate of intestinal transit and producing constipation. The use of opioids in treating pain is often limited due to these undesired side effects, which can be debilitating and often cause patients to refuse the use of opioid analgesics.
In addition to exogenous opioid-induced side effects, studies have suggested that endogenous opioids and opioid receptors may also affect the gastrointestinal (GI) tract and may be involved in normal regulation of intestinal motility and mucosal transport of fluids. Thus, an abnormal physiological level of endogenous opioids and/or receptor activity may also lead to bowel dysfunction. For example, patients who have undergone surgical procedures, especially surgery of the abdomen, often suffer from a particular bowel dysfunction, termed post-operative ileus, that may be caused by fluctuations in natural opioid levels. Similarly, women who have recently given birth commonly suffer from post partum ileus, which may be caused by similar fluctuations in natural opioid levels as a result of birthing stress. Gastrointestinal dysfunction associated with post-operative or post-partum ileus can typically last for 3 to 5 days, with some severe cases lasting more than a week. Administration of opioids to a patient after surgery to treat pain, which is now an almost universal practice, may exacerbate bowel dysfunction, thereby delaying recovery of normal bowel function, prolonging hospital stays, and increasing medical care costs.
Opioid receptor antagonists, such as naloxone, naltrexone, and nalmefene, have been studied as a means of antagonizing the undesirable peripheral side effects of opioids. However, these agents not only act on peripheral opioid receptors but also on opioid receptors in the central nervous system, sometimes reversing the beneficial and desired analgesic effects of opioids or causing symptoms of opioid withdrawal. Preferable approaches for use in controlling opioid-induced side effects include administration of peripheral acting opioid receptor antagonists that do not readily cross the blood-brain barrier.
The peripheral μ opioid receptor antagonist methylnaltrexone has been studied since the late 1970s. It has been used in patients to reduce opioid-induced side effects such as constipation, pruritus, nausea, and urinary retention (see, e.g., U.S. Pat. Nos. 5,972,954, 5,102,887, 4,861,781, and 4,719,215; and Yuan et al., Drug and Alcohol Dependence 1998, 52, 161). The dosage form of methylnaltrexone used most often in these studies has been a solution of methylnaltrexone for intravenous injection.
In U.S. Pat. No. 6,559,158, the dose of methylnaltrexone for treating methadone maintenance patients was explored. It was hypothesized in the '158 patent, based on studies of methadone maintenance patients, that patients taking opioids chronically would be responsive to doses of methylnaltrexone that were previously considered to be too low to be clinically efficacious. (Methadone maintenance patients typically have an addiction to opiates such as heroin, oxycontin, dilaudid or hydrocone. They would have a history of a stable dose of methadone treatment for at least 30 days of greater than or equal to 30 mg/day, and more typically higher.) Low doses of methylnaltrexone were administered intravenously. These doses were between 0.01 and 0.37 mg/kg, wherein average peak plasma levels of 162 (30-774 ng/ml) were reported. These intravenous doses in methadone maintenance patients induced "immediate" laxation.
Methylnaltrexone subcutaneous injection was explored and has been clinically approved in the United States to treat opioid-induced constipation in patients with advanced medical illness who are receiving palliative care. The subcutaneous injection dose found to be effective was 0.15 or 0.3 mg/kg. This dose did not induce "immediate" laxation, but rather induced laxation within 4 hours in a significant number of patients treated.
Attempts have been made to make an oral dosage form of certain opioid antagonists, including methylnaltrexone. In U.S. Pat. No. 6,419,959, an oral dosage form is constructed so as to release certain compounds "over the whole gastrointestinal tract." According to the '959 patent, opioid antagonists are not always suitable for administration in an immediate release form due to dose limiting side effects. In addition, opioid-induced constipation was believed to result from the direct and local effects of opioids on receptors across the entire gastrointestinal tract. To address these issues, the '959 patent suggests dosing certain opioid antagonists, including methylnaltrexone, in a controlled-release dosage form, thereby delivering these antagonists at acceptable doses locally across the entire gastrointestinal tract. Data respecting methylnaltrexone specifically, however, was not reported.
In U.S. Pat. No. 6,274,591, it was demonstrated that an enteric coated methylnaltrexone which released substantially no methylnaltrexone in the stomach was more effective in antagonizing the oral-cecal delay caused by morphine than was an uncoated methylnaltrexone. The '591 patent suggests and claims delivering effective amounts of methylnaltrexone using an oral dosage that by-passes the stomach altogether. Data respecting laxation, however, was not reported.
In U.S. Pat. No. 6,559,158, an oral dose of methylnaltrexone was explored for treating constipation in methadone maintenance patients (i.e., patients shown to be highly sensitive to the effects of methylnaltrexone). The dose of methylnaltrexone administered orally in a capsule was 0.3-3.0 mg/kg. Methylnaltrexone capsules administered to these patients induced laxation in the several patients tested, although over periods of time between 1.2 and 24 hours depending on the dose. The fastest response was seen in the four patients receiving 3.0 mg/kg (5.2+/−4.5 hours, with a range of 1.2-10 hours).
Accordingly, the need exists for bioavailable oral dosage formulations comprising methylnaltrexone.

Oral formulations and lipophilic salts of methylnaltrexone


A method of processing signal data including an unencrypted portion and an encrypted portion, the method including: receiving, at a receiver, the signal data; processing a sample of the signal data to provide a processed signal sample including data relating to the encrypted portion of the signal data and data relating to the unencrypted portion of the signal data, comparing the unencrypted signal data with at least one reference signal to determine information including at least one of (i) the time at which the signal was sent from the source and (ii) the identity of the source; requesting, based on the determined information, and from a source remote to the receiver, a set of encrypted reference signal samples; comparing, on a processing device remote to the receiver, the set of encrypted reference signal samples with the received encrypted signal data to identify any matching signal samples.

Satellite navigation systems such as the Global Positioning System (GPS), Glonass, Galileo, and BeiDou are used to provide position, velocity and timing information to a diverse range of applications. Satellite navigation systems work by broadcasting timing signals to users equipped with receiver devices.
Conventional receiver devices include a module that internally generates signals matching those broadcast by the satellites, referenced to an internal clock. These signals are in a defined format and are specified in open literature for each system. The receiver correlates these internal 'replica' signals with the received satellite signals to extract the correct signal timing and carrier phase and frequency for each satellite. The receiver also decodes the information contained within the satellite broadcast message that enables the receiver to know the location of each satellite.
The receiver uses the results of the correlation process to determine the time of flight for the received signals from each satellite. The time of flight is combined with the information of the location of several satellites in a mathematical process to calculate the position of the receiver antenna.
In addition to supporting an expanding range of commercial applications, satellite navigation systems are used in the field of security and defence. Whereas in the commercial domain, unencrypted, or Open Service, signals are used to obtain the position of the receiver, within the security and defence domain, secure encrypted signals are used. In the Galileo system, this is known as the Public Regulated Service, or PRS, and other systems provide similar services. The secure signals are also broadcast in a predefined format; however such formats are not public information. The satellite system is responsible for encrypting the signals, and the signals are decoded by a specialised secure receiver device.
In a known secure receiver, this is achieved through the use of a security module or security function. The security module is usually a physical component of the receiver. The security module/function contains and processes the cryptographic algorithms that enable the secure signal to be used by the receiver. The security module is capable of generating the required information to receive and process the encrypted signal as well as decoding the encrypted broadcast message that contains information on satellite orbits and clocks and other system and security information. Each receiver requires its own security module/function.
Such security modules will only operate if they have valid cryptographic keys and other parameters/information which are required to unlock the process of decoding the encrypted signals. The keys need to be loaded into the receiver. This process can be done manually (using specific equipment) or autonomously using techniques known as 'over-the-air'. The keys and cryptographic material are critical to the security of the satellite navigation system and therefore there is a need to protect the distribution and management of the material. This can impose a large overhead on the operation of receivers that use encrypted navigation signals.
WO/2012/007720, in the name of Thales, describes a user receiver which includes a capability to capture samples of wideband signals including the Galileo Open Service and the encrypted Public Regulated Service (PRS). The user receiver includes a processing module that can process Open Service signals which are used to compute the position, velocity and time (also called 'PVT' information) of the user as described above. The Open Service PVT information is transmitted with the captured wideband samples to a central server. The central server has access to the secure PRS information which it uses to process the PRS elements of the captured signal. The server uses the PRS information to separately compute the PVT of the user. In this way, the number of PRS security modules which hold the secure cryptographic information can be reduced as it is not a requirement to include a security module in each receiver. The central server compares the Open Service PVT with the server computed PRS PVT and uses the information to carry out an authentication process.
However, this method relies on communicating large volumes of wideband RF captured signal. This has limitations in terms of available communications bandwidth, power required to broadcast the PRS signals samples and the cost of communications. In addition, it requires an Open Service receiver to operate at the user side. In many instances, the user does not require knowledge of his/her position (for example this location information may be provided to a third party, and used as an emergency beacon, or to provide information of how a vehicle is being driven, or the like). To operate an Open Service receiver unnecessarily places additional load on the battery at the user side. Further, the methods and apparatus described rely on the broadcast of open service PVT, and this signal can be intercepted, interfered with or deliberately jammed (which is one of the reasons for the existence of separate encrypted signals).
The NAVSYS Corporation have proposed a low cost GPS sensor, known as the TIDGET, described in U.S. Pat. No. 5,379,224, which utilises a distributed GPS software receiver concept. The TIDGET sensor does not track the GPS signals, but instead captures a "snapshot" of raw GPS samples which are communicated to the central server. At the server, the samples are processed to determine the user's PVT information. A related paper entitled 'PPS Positioning in Weak Signal GPS Environments using a TIDGET Sensor' (Proceedings of ION GNSS 2010, Portland, Oreg., September 2010) describes how the TIDGET concept could be applied to GPS military signals by using the field unit to capture the raw Radio Frequency (RF) data which is communicated to a central server for direct injection into a conventional GPS Precise Positioning Service (PPS) hardware receiver.


In a flat panel display using a field emission type cathode array, a flat fluorescent screen is arranged between a cathode array formed on a flat substrate and a screen comprising a glass plate having a convex curved shape in parallel with the substrate. A vacuum is present in a space between the fluorescent screen and the cathode array and the space between the fluorescent screen and the substrate.

1. Field of the Invention
The invention relates to a flat panel display apparatus and a method of manufacturing thereof, and, more particularly, the invention is suitable when it is applied to a flat panel display using a field emission type cathode array.
2. Description of the Prior Art
Hitherto, as a flat panel display using a field emission, type cathode array comprising microtips having a size on the order of a micron, a display as shown in FIG. 1 is known.
As shown in FIG. 1, in the conventional flat panel display, a silicon dioxide (SiO.sub.2) film 102 having cavities 102a is formed on a conductive flat silicon (Si) substrate 101. Gate electrodes 103 made of molybdenum (Mo), niobium (Nb), or the like are formed on the SiO.sub.2 film 102 in the peripheral portions of the cavities 102a. A cathode 104 made of Mo or the like is formed on the Si substrate 101 in the cavity 102a. A fluorescent screen and be which a fluorescent material 106 is formed on the, flat glass plate 105 is arranged so as to face and be parallel with the Si substrate 101 on which the cathode array is formed. The space between the fluorescent screen and the Si substrate 101 is sealed in a state in which it is held in vacuum.
In recent years, the need to provide a large screen of the flat panel display type is becoming strong. The above conventional flat panel display, however, has a structure in which a differential pressure between the atmospheric pressure and the vacuum is held by only the glass plate 105 on which the fluorescent material 106 is formed. It is, accordingly, difficult to simply enlarge the screen from a viewpoint of the strength of the glass plate 105.
To solve the above problem, there is considered a method of realizing a large screen by forming the screen into a spherical shape as shown in FIG. 2, as in the case of the cathode ray tube of an ordinary television receiver. When such a, structure is used, however, the formation of a portion thereof in which a distance between the cathode array and that portion of the fluorescent screen is large cannot be avoided. In the above conventional flat panel display, however, it is necessary to closely arrange the cathode array and the fluorescent screen in terms of operation principle. Therefore, when the screen is simply formed in a spherical shape as mentioned above, a problem occurs in the operation of the flat panel display. To prevent it, there is also considered a method whereby the Si substrate is also formed in a spherical shape and the cathode array is formed on the Si substrate. It is, however, extremely difficult to realize such a structure from a viewpoint of the manufacturing processes.
Therefore, in the flat panel display shown in FIG. 1, there is considered a method whereby pillars are formed at regular intervals between the glass plate 105 and the Si substrate 101, and the differential of pressure between the atmospheric pressure and the vacuum is held by the pillars. When such a structure is used, however, there are problems such that not only the manufacturing processes become complicated but also the cathode 104 cannot be formed on the Si substrate 101 in the portion of the pillar.
From the above reasons, it has been thus difficult so far to realize a large screen of the flat panel display using the field emission type cathode array.
On the other hand, as a method of manufacturing a flat panel display using a field emission type cathode array by microtips of a size on the order of micron order, a method as shown in FIGS. 3A to 3E known. According to the manufacturing method, as shown in FIG. 3A, an SiO.sub.2 film 102 is first formed on a conductive Si substrate 101 by, for instance, a thermal oxidation method, a CVD method or a sputtering method. After that, a metal film 107 made of, for example, Mo film, a Nb film, or the like to form gate electrodes is formed onto the SiO.sub.2 film 102 by, e.g., a sputtering method or an electron beam evaporation depositing method. Subsequently, a resist pattern 108 having shapes corresponding to the gate electrodes to be formed are formed onto the metal film 107 by a lithography.
The metal film 107 is subsequently etched by a wet etching method or a dry etching method by using the resist pattern 104 as a mask, thereby forming gate electrodes 103 as shown in FIG. 3B. After that, the SiO.sub.2 film 102 is etched by a wet etching method or a dry etching method by using the resist pattern 108 and the gate electrodes 103 as masks, thereby forming cavities 102a.
After the resist pattern 108 was removed, as shown in FIG. 3C, an oblique evaporation deposition is executed to the substrate surface by an electron beam evaporation depositing method from the direction which is inclined by a predetermined angle to the substrate surface, thereby forming a peeling-off layer 109 made of, e.g., aluminium (Al) or nickel (Ni), onto the gate electrodes 103. After that, for instance, Mo as a material to form cathodes is evaporation deposited onto the substrate surface by an electron beam evaporation depositing method from a direction perpendicular to the substrate surface. Thus, cathodes (emitters) 104 comprising microtips are formed onto the Si substrate 101 in the cavities 102a. Reference numeral 110 denotes a metal film which has been evaporation deposited onto the peeling-off layer 109.
The peeling-off layer 109 is subsequently removed by a lift-off method together with the metal film 110 formed on the peeling-off layer 109, so that a state shown in FIG. 3D is obtained. After that, as shown in FIG. 3E, a screen in which a fluorescent material 106 is formed on a glass plate 105 serving as a display screen is arranged so as to face the Si substrate 101 on which the cathode array is formed in a manner such that the fluorescent material 106 is positioned on the inside. The space between such a screen and the Si substrate 101 is sealed in a state in which it is held in vacuum. A desired flat panel display is consequently completed.
Upon operation of the flat panel display, a negative voltage of, e.g., about -50 V is applied to each cathode 104.
In the foregoing conventional manufacturing method of the flat panel display, it is extremely difficult to align all of the radii of curvatures of the tips of a number of (for instance, tens of thousand) cathodes 104 which are simultaneously formed by an evaporation depositing method, and the occurrence of a slight variation in the radii of curvatures of the tips of the cathodes 104 can hardly be avoided.
On the other hand, as shown in FIG. 4, there is generally a correlation between the radius of curvature of the tip of the cathode and an allowable applied voltage to the cathode. In FIG. 4, Vmin denotes a minimum voltage (absolute value) at which a current emission can be performed and vmax indicates a maximum voltage (absolute value) at which a current emission can be executed without causing a discharge. As will be understood from FIG. 4, as a radius of curvature of the tip of the cathode increases, a voltage at which the current emission can be performed rises. Therefore, if only one cathode whose radius of curvature of the tip is smaller than those of,, the other cathodes exists, for instance among tens of thousands of cathodes, when a negative voltage is gradually applied to those cathodes whose tip radius of curvature is smaller, a problem arises. The problem is that when the current emission starts from the other cathodes, the voltage exceeds the allowable applied voltage, and those cathodes discharge. Thus the tips thereof are rounded, and the current emission stops.
To solve the above problem, a method whereby a resister is provided between each cathode and a power source to thereby prevent the occurrence of the emission of a predetermined current or higher has also been proposed. There is a problem such that the above method is extremely difficult from a viewpoint of the manufacturing processes.

Flat panel display apparatus and a method of manufacturing thereof


Methods and modules for using physiological (biometric) variables to advance the state of the artificial pancreas. The method and system includes one or more modules for recursive model identification, hypoglycemia early alert and alarm, adaptive control, hyperglycemia early alert and alarm, plasma insulin concentration estimation, assessment of physical activity (e.g., presence, type, duration, expected effects on insulin sensitivity and GC), detection of acute stress and assessment of its impact on insulin sensitivity, detection of sleep and its stages and assessment of sleep stages on GC, sensor fault detection and diagnosis, software and controller performance evaluation and adjustment and/or pump fault detection and diagnosis.

Patients with Type 1 diabetes (T1D) must receive insulin from external sources in order to regulate their blood glucose concentration (BGC). Excess glucose in the blood can damage the blood vessels. This leads to several complications such as cardiovascular disease, damage to kidneys, nerves, and eyes, and difficulty in wound healing. Diabetes is the fastest growing long-term disease that affects millions of people worldwide. Diabetes affects 25.8 million people in United States and about 5% of diabetes cases are T1D in adults. Diabetes is considered to be the seventh leading cause of death in the United States and the cost of diabetes to the nation has been estimated to be $174 billion in 2007.
Most patients with T1D either administer multiple (3-5) daily insulin injections (MDI) or use insulin pumps for continuous subcutaneous insulin infusion (CSII). In CSII, basal insulin is infused continuously and bolus insulin is administered before meals to maintain BGC in the target range (70-180 mg/dl). T1D patients may experience hypoglycemia (BGC≤70 mg/dl) episodes that may be caused by insulin doses that are too large in relation to the BGC, reduced food intake, extensive physical activity, or slow absorption of currently available "fast acting" insulins. Hypoglycemia causes dizziness, unconsciousness, and seizures and if untreated diabetic coma or death. Fear of hypoglycemia is prevalent among patients with T1D and a concern in use of insulin pumps.
An artificial pancreas (AP) will automate insulin pumps by using a controller that receives information from sensors, computes the optimal insulin amount to be infused and manipulates the infusion rate of the pump. Fear of hypoglycemia is a major concern when the insulin infusion rate is under automatic control. An AP that can predict BGC accurately and compute infusion rates that will keep BGC in the target range without causing hypoglycemia would be very beneficial. Control systems that minimize the information to be entered by the user to the AP such as meal and exercise information would make life easier for patients with T1D.
Various control strategies such as proportional-integral derivative (PID) control, model predictive control (MPC), fuzzy logic control, and generalised predictive control (GPC) have been proposed for the regulation of BGC in patients with T1D. Furthermore, a bihormonal system (insulin+glucagon) that uses PID, MPC, and GPC has also been investigated. Complexity of glucose homeostasis and the current level of technology prevents tight BGC regulation. BGC dynamics are subject specific and time varying. Since a single good model that describes BGC dynamics of individuals does not exist, models have to be developed based on measurements from individuals. A single model based on some training data is not sufficient for controller design since BGC dynamics are time varying for each individual. Also a model based on data from one person would not be suitable for representing the BGC dynamics of another person. Recursive time-series models were shown to be a powerful tool for describing and predicting the dynamics of BGC, hypoglycemia alarm systems, and closed-loop control. There is a continuing need for improved recursive model development, guaranteed stability of every model developed, and adaptive control based on these recursive models.
Meals, physical activity, and emotional state are some of the factors that affect BGC. Using information from such factors improves the performance of BGC regulation. Meal information is used by many researchers to compute the amount of insulin bolus to be infused. However, use of information manually entered by patients should be balanced with convenience and adherence. Patients may forget to enter meal information in a timely manner or make erroneous estimates about the carbohydrate content of the meal. The protein, fat, and carbohydrate ratios of the foods impact the glycemic value of the meal ingested. Thus there is a continuing need for improved method and systems for an artificial pancreas.

Multivariable artificial pancreas method and system


A biocidal wax composition for preventing corrosion and biological fouling nd surface degradation of submerged structures comprises from about 10 to about 40 percent of total biocidal wax composition of a biocidal polymeric gel consisting of a polymer from the group consisting of a polyethylene, polypropylene, a copolymer of polyethylene and vinyl acetate, and mixtures thereof and a solvent selected from the group consisting of mineral oil, a paraffin wax and mixtures thereof, and a biocide; and from about 60 to about 90 percent of total biocidal wax composition of a wax matrix composition consisting of petrolatum, at least two chlorinated waxes, and a microcrystalline wax. The biocidal wax is prepared by shock-cooling a hot solution of a polymer through its cloud point, admixing a biocide with the gel, and admixing the above wax matrix composition with the gel.

This invention pertains generally to coatings and particularly to bioactive wax coatings.
The drag of a ship's hull increases significantly from micro to macro hard fouling which results from the attachment of marine organisms, such as bacteria, algae and barnacles, on the hull surface. Even after these organisms are removed, the smoothness of the hull is seriously reduced by the pitting caused by these organisms.
Other submerged structures experience deterioration caused by marine growth or corrosion. Wooden blocks and piers can be destroyed in a few years if left untreated. Many of the traditional treatments, e.g., creosote, create serious environmental problems. Metal structures, e.g., propellers and anchor chains, lose appreciable performance capability or strength through corrosion and marine growth on their surfaces.
One approach to reducing marine growth is coating the surface with a coating toxic to marine organisms. The coating usually comprises a matrix with one or more toxic materials in the matrix.
A frequently used type of matrix is resinous and forms a paint. The disadvantages of paints are their expense, the diminution of their effectiveness in time, the difficulty of mechanically renewing the smoothness of the paint surface, and the frequent corrosive effect of the toxic substances on the metallic hull.
Instead of coating a hull with toxic paint, the hull can be coated with non-toxic paint that is coated with a biocidecontaining wax. Toxic waxes are also used to renew toxic paint surfaces after the paint has lost its toxicity. The wax coating disclosed in U.S. Pat. No. 4,020,200 by Groszek et al. is typical, i.e., a wax with a stable biocide that is insoluble in seawater but soluble in the wax. Another example is the wax composition in U.S. Pat. No. 4,115,130 by Crump et al. which also includes porous minerals to slow the release of the biocide.
The rate of release is important to biocidal coatings because if the biocide is released too quickly an environmental problem is created and the coating becomes ineffective too quickly. On the other hand, the rate of release must be sufficient to maintain the required biocide concentration at the surface of the submerged structure.
The wax compositions in U.S. Pat. Nos. 4,410,363 and 4,293,339 by R. F. Supcoe and T. Radakovich utilize certain halogenated waxes and wax combinations to provide superior adhesion to a submerged surface and retention of the biocide to provide a very durable and effective coating for retarding marine growth on the submerged surface. The wax composition in U.S. Pat. No. 4,293,339 has the additional important advantage of being capable of underwater application. The other wax compositions require the removal of the surface from the water or the water from the surface before an effective coating on the surface is possible, i.e., a coating that is smooth, continuous, uniform and strongly adhering. The disadvantage of the above wax composition is the use of one or more fluoropolymers which greatly increases the cost of the wax coating.
A biocidal wax coating that can adhere strongly to a surface to form a smooth durable coating over a wide range of temperatures, even if the wax is applied under water or on a wet surface, is an important improvement in the technology. If such a wax can be compounded without fluoropolymers, the versatility and cost of this wax would permit a wide variety of uses.

Underwater biocidal wax composition and preparation thereof

The United States of America as represented by the Secretary of the Army


A process is disclosed for etching a silicon-based structure comprised of a silicon layer and a high-melting silicide layer. Good shaping results from etching of the two layers with use of two gaseous mixtures having their respective different ratios of a hydrogen bromide gas and a fluorine radical-donating gas. Separate etching is possible of the silicon layer with a hydrogen bromide gas and of the silicide layer with a gaseous mixture of the above type. A silicon-containing layer is also etched with a hydrogen gas alone with the end point of etching being precisely detected.

1. Field of the Invention
The present invention relates to a process for etching silicon-based materials mainly of a character having disposed on a substrate either one or both of a silicon layer and a silicon-containing layer. Such process is suitable particularly for use in etching so-called polycide structures in the manufacture of semiconductors.
2. Description of the Related Art
As is generally know in the art of electronic components such as semiconductors and the like, those materials comprised of a substrate and at least one silicon layer laminated thereon can be etched for patterning. One typical material has superposed on a substrate a silicon layer and a high-melting silicide layer, finding its use for gate wirings on semiconductors.
High-melting silicides are advantageous as they are smaller in sheet resistance than polycrystalline silicons commonly acceptable as gate wiring materials for conventional circuits of a large-scale integration type (LSI). Further, the silicide when superposed on a silicon layer or a polysilicon layer in particular has been formed to retain the resultant interface at a highly reliable level. This reliability is seen at an interface defined by such a silicon layer together with silicon dioxide (SiO.sub.2) as a gate-insulating film.
The above silicon-silicide composite material is usually named a polycide structure from lamination of a silicide on a polysilicon.
As a result of the advent of high-speed LSI circuits, polycide structures have recently become prominent for gate formation. This entails various modes of etching.
To attain desired patterning, a given polycide structure is required to be etched with its two different layers held in anisotropic relation to each other. A family of gases know as chlorofluorocarbons (CFC) has been used among which is typified 1,1,2-trichloro-1,2,2-trifluoroethane (C.sub.2 Cl.sub.3 F.sub.3) (CFC113). These gases, however, are reported to rise into the stratosphere and to erode the ozone layer, posing serious environmental problems. Warnings are being made to phase out the use of such ozone-depleting chemicals.
Great concern has been directed toward the prevision of a substitute gas which is highly capable of exerting an anisotropic action on both silicon and high-melting silicide layers, thus ensuring etching in good shape. Hydrogen bromide (HBr) attracts much attention, for its inherent ability to etch with high anisotropy and high selectivity, as a replacement for the CFC gases. One problem with HBr is that no method is established for detecting the end point of etching in the case where the gas is used alone. This means that HBr does not warrant commercial acceptance in etching silicon-based materials for gate formation.
The present inventors have previously found that polycide structures can be etched into the form of films at increased rates of production and with improved magnitudes of anisotropy and selectivity as disclosed in Japanese Patent Application No. 2-10489. This mode of etching is designated to use a mixture of an HBr gas with a fluorine radical-donating gas such as sulfur hexafluoride (SF.sub.6). The HBr-SF.sub.6 gas is undesirable for etching a silicon layer such as of a doped polysilicon (DOPOS) under the same etch conditions as in a high-melting silicide layer such as of a tungsten silicide (WSi.sub.x). The silicon layer is necessarily susceptible to objectionable side etching.


A lithium ion rechargeable cell that is constructed by the steps of forming a cell unit (1) by packing an electrode group (10), in which plate-like positive and negative electrodes (12 and 14) and a plate-like separator (16) are superposed in layers, in a cell case (20) and sealing the electrode group together with an electrolyte; and forming a module by aligning and packing a plurality of cell units in a module case. The cell case is made of a laminated film (22). A porous spacer (30) made of insulating material is interposed in between the entire circumferential surface or partial surface of the electrode group and the laminated film.

1. Field of the Invention
The present invention relates to a lithium ion rechargeable cell, and more specifically, to a cell case of a lithium ion rechargeable cell.
2. Description of the Related Art
In general, a lithium ion rechargeable cell is modularized. One module is constructed in the following manner. First, an electrode group, in which plate-like positive and negative electrodes and a plate-like separator are alternately superposed in layers, is packed in a cell case and sealed together with an electrolyte. The result is a cell unit. Several cell units are aligned and packed in a module case to produce a module.
A cell case and a module case have been generally fabricated with an undeformable rigid case that is made of, for example, resin or metal.
Therefore the capacity of the module case made with a rigid case is previously determined, so that the total cubic volume of the cell units contained in the module case is also previously determined.
If the cell case is made with a rigid case similarly to the module case as in the past, the relatively thick walls of the cell case limit the number of electrode plates that can be packed in the cell case. The capacity of the cell case is accordingly limited, too.
In order to enhance the workability of packing an electrode group in the cell case, an extra space is needed in the cell case. If the cell case is fabricated with an undeformable rigid case, it is difficult to make an efficient extra space, and the containing capacity is also limited.
Since the cell case fabricated with a rigid case is limited in capacity, it is difficult to achieve a compact and high-capacity lithium-ion rechargeable cell module.
If the capacity of each cell case is increased, the total cubic volume of wall thickness of the cell cases is reduced as a whole. On the other hand, as a result of increase of the cubic volume of each cell case, the number of cell cases that can be packed in a module case is decreased. This causes another problem that voltage is reduced unless electrode plates, an electrolyte and others are changed.
In light of the above problems, a lithium ion rechargeable cell has been contrived. This lithium ion rechargeable cell uses a wrap-type pouch case as a cell case, and contains an electrode group that is wrapped in a laminated film and depressurized so that the electrode group and the laminated film are firmly adhered together (Unexamined Japanese Patent Publication No. 2004-103415).
If the cell case is made with a wrap-type pouch case as described, it is possible to reduce the wall thickness of the cell case and smoothly pack the electrode group in the cell case without extra space. The lithium ion rechargeable cell can be configured without a change in outer size of the cell case. At least the module case fabricated with a rigid case is quite capable of absorbing external impacts.
On the other hand, if the electrode group is simply covered with a laminated film as described above, an adhesion degree between the laminated film and the electrode group is high. Due to the high adhesion degree, in spite that the lithium ion rechargeable cell needs to use a liquid electrolyte, the electrolyte cannot be sufficiently injected in between the laminated film and the electrode group.
If the electrolyte is not be sufficiently injected into the cell case, this raises problems including an increase in internal resistance, and also incurs a deterioration in power generation efficiency. The technology disclosed in the above-mentioned publication interposes an elastic body in between the laminated film and the electrode group. However, the situation is still the same.
One idea for solving this problem is to lower the adhesion degree between the laminated film and the electrode group. If the adhesion degree is lowered, the cell case becomes unstable in shape. This adversely affects the packageability of the cell case into the module case, that is, the manufacture efficiency of lithium ion rechargeable cells. Furthermore, if the adhesion degree is simply reduced, gaps between the laminated film and the electrode group would be uneven, and the electrolyte cannot be uniformly injected. This causes another problem that the power generation efficiency is not successfully improved.

Mitsubishi Jidosha Kogyo Kabushiki Kaisha


A circuit arrangement which comprises at least one stage which is to be fed by a source voltage from a common voltage source, at least one of these stages comprising a control signal generating circuit which can apply a control signal, to be derived from the source voltage, to a control signal output bus conductor which is common to all stages. A control signal input bus conductor can be connected to the control signal output bus conductor via a central bridge when the source voltage has a value within a first value range and which can be isolated from the control signal output bus conductor by the central bridge when the source voltage has a value within a second value range. Each stage includes a respective control circuit which can be connected to the control signal input bus conductor in order to receive the control signal and which can adjust the stage to a source voltage from the associated value range by application or interruption of the control signal. Thus, the circuit arrangement simply adapts the stages fed by the voltage source to the particular source voltage.

This invention relates to a circuit arrangement which comprises least one stage which is to be fed by a source voltage from a common voltage source.
Circuit arrangements of this kind are used, for example, in telecommunication systems, to supply a system of usually several telecommunication devices with electric energy from a common voltage source, for example, a central battery of a telecommunication centre or an emergency power supply. Central batteries of this kind supply source voltages having essentially two different nominal values, i.e. 48 volts and 60 volts. When a circuit arrangement of the kind set forth is used in conjunction with a given central battery or the like, all stages to be fed with electric energy therefrom must be adapted to the nominal value of the source voltage. This may necessitate undesirably intricate adjusting operations during installation as well during operation.

Plural stage circuit with automatic adaptation to first and second voltage ranges of a common voltage source


A torsional vibration absorber for a vehicle is provided. The torsional vibration absorber including a front pilot bearing adapted to couple with a vehicle shaft. A spring member is coupled to the front pilot bearing. An inertia ring having an inner surface is operably coupled to the spring member, wherein the front pilot bearing is centrally disposed along the length of the inertia ring. A rear pilot bearing is adapted to couple with the vehicle shaft, the rear pilot bearing having a portion adjacent the inner surface at one end of the inertia ring.

Vehicles, such as automobiles and trucks for example, include a rear drive module (RDM) that is connected to the vehicle engine by a prop-shaft. The prop-shaft transmits rotational energy (torque) developed by the vehicle engine to the rear drive module, which in turn transmits the rotational energy to the wheels. In a rear-wheel drive vehicle, the prop-shaft directly couples the RDM to the vehicle's transmission. In an all-wheel or four-wheel drive vehicle, additional components may also be included, such as a power take-off unit for example.
During operation, torsional vibrations generated by the engine may be transmitted along the prop-shaft to the RDM. In some situations, these torsional disturbances may result in undesired noise or increased component wear.
Accordingly, it is desirable to provide a means for damping torsional vibrations in the prop-shaft prior to the RDM.

Torsional vibration absorber for a vehicle


There is disclosed a method for producing a metal oxide, which comprises the steps of: dissolving a metal organic compound (e.g. a metal organic acid salt, a metal acetylacetonato complex, and a metal alkoxide having an organic group with 6 or more carbon atoms) in a solvent to provide a state of solution, applying the solution onto a substrate, drying the solution, and subjecting the resultant substrate to irradiation with a laser light of a 400 nm or less wavelength, to form a metal oxide on the substrate. According to that method, a metal oxide can be produced without applying a heat treatment at a high temperature of the degree adopted in the conventionally known application thermal decomposition method.

The present invention relates to a method for producing a metal oxide. The present invention also relates to a method for forming a minute pattern.
Formation of a thin film made up of a metal film, a metal oxide film, or a composite oxide film on a substrate, is actively performed in the field of the semiconductor production technology. In forming the metal film, the metal oxide film, or the composite oxide film on the substrate, a method of using a metal organic compound containing the metal species as a raw material, applying a homogeneous solution, obtained by dissolving the compound in a solvent, onto the substrate, heating, and baking, has been usually utilized.
However, in general, according to the method, in producing a metal oxide by heating and baking after application, metal ions which can be the cores aggregate together, to cause crystal growth and powdering. In order to eliminate this problem, it is considered necessary to take a measure to prevent contact of the metal ions with each other; that is, a means to isolate the metal ions by utilizing the steric hindrance effect. As such a means, specifically, separation of the metal ions by a large organic group can be considered.
Based on the idea, if an organic group bonding metal is selected and is thermally decomposed, core formation and crystal growth are restrained. As a result, a metal oxide can be obtained in the amorphous state, and the same will further be crystallized. Accordingly, when the desired metal oxide is to be in a film state, since it is provided via the amorphous state, a film with an improved film formation property can be obtained, and thus it became known that the film formation itself is not difficult. The above method is called the application thermal decomposition method, and it was extensively studied by Toru Matsushita et al. in the 1970s. The application thermal decomposition method is aimed at forming a metal oxide film or a composite oxide film by applying a homogeneous film of good quality on a substrate, and a heat-baking treatment. T. Matsushita et al. pointed out that an organic group bonding metal compound having a metal-oxygen-carbon bond is suitable as a raw material, and they mainly studied particularly a metal organic acid salt having a large organic group (Ceramics, 21, 236 (1986)).
As a raw material for the above operation, originally, a method of using a metal acetylacetonato complex for forming a metal oxide film on a substrate, by decomposing the metal acetylacetonato, was developed. Specifically, a method of forming a highly functional oxide film by only applying a raw material solution on a substrate, and applying a heat treatment thereto, was proposed, which attracted attention (U.S. Patent by American inventors concerning In2O3 film (transparent conductive film) in 1956 (M. S. Jaffy et al., JP-B-31-3282 (1956) (xe2x80x9cJP-Bxe2x80x9d means examined Japanese patent publication))).
Studies have been done since then on the methods of using a metal acetylacetonato complex as a raw material. However, as mentioned below, a problem is involved, in that disadvantages of applying heat cannot be avoided.
In contrast, general decomposition or reaction by radiating light onto a metal acetylacetonato complex has been performed since long ago (N. Filipescu et al., Inorg. Chem. 8 1863 (1969)) (H. D. Gafney et al., Inorg. Chem. 9 1728 (1970)) (H. D. Gafney et al., J. Am. Chem. Soc. 93 1623 (1971)).
However, products obtained by these methods so far were not metal oxides; rather, they consisted of a metal or a composition with the valence of the metal ion changed, and no oxide was really obtained.
Meantime, according to the superconductivity fever of the mid 1980s, superconductive epitaxial films, using various kinds of single crystal substrates, were synthesized for the first time by the application thermal decomposition method, using a metal organic acid salt as the raw material (Susumu Mizuta et al., Nihon Kagakukaishi (Journal of the Chemical Society of Japan) 1997, (1) 11-23 (1997); S. Mizuta et al., Japanese Patent Registration No. 1778693; S. Mizuta et al., Japanese Patent Registration No. 1778694; Toshiya Kumagai et al., JP-A-5-14794 (xe2x80x9cJP-Axe2x80x9d means unexamined published Japanese patent application), and T. Kumagai et al., JP-A-5-9022).
Furthermore, from the 1990s, studies on synthesis of an epitaxial film for production of a ferroelectric substance, such as Pb(Zr)TiO3 (K. Hwang et al., Jpn. J. Appl. Phys. Vol. 36, Part 1, No. 8, pp. 5221-5225 (1997)), BaTiO3 (S. Kim et al., Trans. Mater. Res. Soc. Jpn., 20, p. 636-639 (1996)), La(Sr)MnO3 (T. Manabe et al., J. Mater. Res., 12(2), p. 541-545 (1997)), and LiNbO3 (T. Manabe et al., Trans. Mater. Res. Soc. Jpn., 20, p.599-602 (1996)), have been pursued.
According to a method of producing a metal oxide using a metal acetylacetonato complex, in general, treatment at a high temperature of 500xc2x0 C. or more is required for decomposing the metal acetylacetonato. According to a recent method (K. Shinmou et al., Jpn. J. Appl. Phys. 33 L1181 (1994)), patterning is performed by adding acetylacetone to a metal alkoxide and radiating with ultraviolet rays, to make the film insoluble. However, a metal oxide cannot be obtained by this method. In order to obtain an oxide, heat treatment is finally necessitated.
Moreover, in the case of using a metal organic acid salt as the raw material, decomposition at 500xc2x0 C. or more is inevitable, but it is pointed out that such a high temperature thermal decomposition causes several harmful effects on electronics devices.
For example, in the case of using a silicon, it is known that deterioration is caused and laminated films react with each other. In order to prevent deterioration of silicon or reaction among the laminated films, it is said that the heat treatment temperature should be 650xc2x0 C. or less, desirably 300xc2x0 C. or less.
As mentioned above, decomposition at a high temperature close to 500xc2x0 C. is too high for electronics devices, and harmful influences thereby are pointed out. For example, in the case of PZT, which is expected as a dielectric memory, the PbO component thereof reacts with a silicon substrate, to lower the dielectric characteristics. Moreover, for a transparent conductive film made, for example, of indium oxide, which is used as an electrode of photonics, or electronics devices related to a light, such as a liquid crystal display board, a plasma display panel, and a solar battery, a high-temperature heat treatment of the above-mentioned degree is not preferable. In particular, in the case of a color liquid crystal display board, since a film needs to be formed on an organic compound resin color filter, a low-temperature film formation, preferably in the range of 150 to 170xc2x0 C., is desired. However, there has been no case of converting a metal acetylacetonato complex to an oxide film in 100%-yield by treatment at a relatively low temperature.
Accordingly, a specific example of decomposition at 200xc2x0 C. or less has not been known so far either in the case of acetylacetonato or a metal organic acid salt. As a heating means, use of various kinds of heat sources are conceivable, but the use of new means has not been known.
As a heating means, radiation by an excimer laser, which radiates ultraviolet rays having a high heating effect and high-level energy, without containing a wavelength at the infrared part, is expected; however, a specific example of producing an oxide using the excimer laser has not been reported so far.
That is, it has been considered to be difficult to decompose a metal acetylacetonato or a metal organic acid salt for synthesizing an oxide directly since both of these are known to be stable. Furthermore, there are no reports on decomposition using a metal alkoxide having an organic group with 6 or more carbon atoms as the raw material. Direct synthesis of an oxide film using an organic group with 5 or less carbon groups, for example, decomposition of an alkoxide comprising i-propoxide as an organic group with 5 or less carbon atoms, is known already. However, in the method, an excimer laser is used in irradiation at the time of crystallization after preliminary polycondensation of the raw material substance (H. Imai et al., J. Appl. Phys. 85 (1999)203). Thus the excimer laser irradiation is used as an auxiliary means for the polycondensation operation but not for decomposing the alkoxide to directly obtain a metal oxide.
An object of the present invention is to provide a method for producing a targeted metal oxide without applying a heat treatment at a high temperature of the degree adopted in the conventionally known application thermal decomposition method. According to the method for producing the metal oxide to be formed on the surface of a substrate in the state of a metal oxide film or a composite oxide film, a method capable of enabling a minute process can be provided.
More specifically, another object of the present invention is to provide a method for producing a metal oxide and a metal oxide film without deterioration of the substrate, wherein the metal oxide formed on the substrate is not given a high-temperature heat treatment. Still another object of the present invention is to provide a method for forming a minute pattern.
Other and further objects, features, and advantages of the invention will appear more fully from the following description.
The present inventors found that, by irradiation with a laser light having a wavelength of 400 nm or less, to a metal organic compound applied on a substrate, instead of the process of heating and baking at a high temperature of about 500xc2x0 C., the metal organic compound can be decomposed so as to produce a metal oxide on the substrate, without heating the substrate and the produced film to 500xc2x0 C. or more. This can be attained since the laser light irradiation has the heating effect and the effect of providing a strong energy of the laser light. As a result, we have completed the present invention based on that finding. The phenomenon of the thermal decomposition according to such the effects were discovered by the present inventors for the first time.
The present inventors also found out newly that, in the case of decomposing a metal organic compound, a metal oxide may be obtained in one step; however, even when the decomposition cannot be occurred in one step, reaction can be carried out by a two-step decomposition reaction. Specifically, for example, we have found that a metal organic acid salt can be decomposed in two steps to obtain a metal oxide, to also thereby complete the present invention.
The matters discussed are as follows.
First, iron 2-ethylhexanoate solution (Fe content 6 wt %) was diluted twofold with toluene. After spin-coating the same on a quartz substrate at 2,000 rpm for 10 seconds, it was dried at 200xc2x0 C. for 10 minutes. Then, an ArF excimer laser (193 nm) was used to irradiate at 10 Hz and 50 mJ/cm2 for 5 minutes in air, but the iron 2-ethylhexanoate was not decomposed. A two-step irradiation, including a first-step irradiation of 10 mJ/cm2 at 50 Hz for 30 seconds, and a second-step irradiation of 50 mJ/cm2 at 10 Hz for 5 minutes in air, was conducted. The product obtained by the irradiation was analyzed by X-ray diffraction measurement. As a result, production of a xcex3Fe2O3 film was confirmed.
As to why such plural-step energy irradiation is effective, and why decomposition cannot be done with a one-step irradiation with strong energy enough to cause decomposition, the possibility of ablation by the iron 2-ethylhexanoate is conceivable as one of the reasons, but details are not known yet. Moreover, as to why decomposition can be done by the second irradiation when only weak energy was used in the first-step of preliminary irradiation, it can be conceivable as a result of stabilization of iron 2-ethylhexanoate or an increase of the interaction between iron 2-ethylhexanoate molecules and the substrate according to the removal of the solvent that takes place preliminary in the first-step irradiation.
In either case, it was apparently observed that a metal organic acid salt is decomposed by irradiation of a laser light of a wavelength of 400 nm or less over a plurality of steps, to give a metal oxide.
Furthermore, the present inventors found out that, similarly as to indium 2-ethylhexanoate and tin 2-ethylhexanoate, crystalline In2O3, SnO2 can be obtained by performing two-step irradiation by an ArF excimer laser light in each case.
The present invention was completed by finding out the above-mentioned phenomena for the first time.
According to the present invention, the following methods are provided.
(1) A method for producing a metal oxide, comprising the steps of: dissolving a metal organic compound in a solvent to provide a state of solution, applying the solution onto a substrate, drying the solution, and subjecting the resultant substrate to irradiation with a laser light of a 400 nm or less wavelength, to form a metal oxide on the substrate.
(2) The method for producing a metal oxide as stated in the above (1), wherein an excimer laser, which uses one selected from the group consisting of ArF, Krf, XeCl, XeF, and F2, is used as the laser light of a 400 nm or less wavelength.
(3) The method for producing a metal oxide as stated in the above (1) or (2), wherein the laser light irradiation of a 400 nm or less wavelength is carried out in a plurality of steps.
(4) The method for producing a metal oxide according to any one of the above (1) to (3), wherein the laser light irradiation of a 400 nm or less wavelength is carried out in a plurality of steps, and wherein the first-step irradiation is carried out with a weak irradiation in a degree that does not completely decompose the metal organic compound, and the next irradiation is carried out with a strong irradiation capable of changing the metal organic compound to an oxide.
(5) The method for producing a metal oxide according to any one of the above (1) to (4), wherein the metal organic compound is a mixture of two or more compounds comprising different metals, and the obtainable metal oxide is a composite metal oxide comprising the different metals.
(6) The method for producing a metal oxide as stated in any one of the above (1) to (5), wherein the solution containing the metal organic compound contains an organic amine as a photosensitizer.
(7) The method for producing a metal oxide according to any one of the above (1) to (6), wherein the metal organic compound is a metal organic acid salt.
(8) The method for producing a metal oxide as stated in the above (7), wherein the metal of the metal organic acid salt is selected from the group consisting of iron, indium, tin, zirconium, cobalt, nickel, and lead.
(9) The method for producing a metal oxide as stated in the above (7) or (8), wherein the organic acid of the metal organic acid salt is selected from the group consisting of naphthenic acid, 2-ethylhexanoic acid, caprylic acid, stearic acid, lauric acid, butyric acid, propionic acid, oxalic acid, citric acid, lactic acid, benzoic acid, salicylic acid, and ethylenediaminetetraacetic acid.
(10) The method for producing a metal oxide as stated in the above (7), wherein the metal organic acid salt is selected from the group consisting of iron 2-ethylhexanoate, indium 2-ethylhexanoate, and tin 2-ethylhexanoate.
(11) The method for producing a metal oxide according to any one of the above (1) to (6), wherein the metal organic compound is a metal acetylacetonato complex.
(12) The method for producing a metal oxide as stated in the above (11), wherein the metal of the metal acetylacetonato complex is selected from the group consisting of titanium, indium, tin, zirconium, and zinc.
(13) The method for producing a metal oxide as stated in the above (11) or (12), wherein the solvent for dissolving the metal acetylacetonato complex is selected from the group consisting of butyl acetate, toluene, acetylacetone, and methanol.
(14) The method for producing a metal oxide according to any one of the above (1) to (6), wherein the metal organic compound is a metal alkoxide having an organic group with 6 or more carbon atoms.
(15) The method for producing a metal oxide as stated in the above (14), wherein the metal of the metal alkoxide is titanium.
(16) The method for producing a metal oxide as stated in the above (14), wherein the alkoxyl group of the metal alkoxide is a 2-ethylhexanol group.
(17) A method for forming a minute pattern, comprising the steps of: subjecting a thin film layer containing a metal organic compound provided on a substrate, to irradiation with a laser light of a 400 nm or less wavelength according to a predetermined pattern shape or through a predetermined mask pattern, to form a metal oxide, and dissolving and removing the non-irradiated part with a solvent, to form a minute pattern.
(18) The method for forming a minute pattern as stated in the above (17), wherein the laser light irradiation of a 400 nm or less wavelength is carried out in a plurality of steps.
(19) The method for forming a minute pattern as stated in the above (17) or (18), wherein the laser light irradiation of a 400 nm or less wavelength is carried out in a plurality of steps, and wherein the first-step irradiation is carried out with a weak irradiation in a degree that does not completely decompose the metal organic compound, and the next irradiation is carried out with a strong irradiation capable of changing the metal organic compound to an oxide.
(20) The method for forming a minute pattern as stated in any one of the above (17) to (19), wherein, after the minute-pattern formation, the minute pattern is used as a mask to carry out dry etching, thereby forming a minute pattern on the substrate.
A metal oxide and a film comprising a metal oxide obtained by the method of the present invention is formed on a substrate.
As the substrate to be used, in general, any substrate can be used, as long as it has a smooth surface and is physically, chemically, and mechanically stable in air at a room temperature, and thus a metal or a metal oxide, and a single crystal or a polycrystal thereof, can be used. In either case it is not limited to a specific type but can be optionally selected and used as needed. Specific examples thereof include Si, SiO2, MgO, SrTiO3, LaAlO3, and xcex1-Al2O3. The surface of the substrate should be maintained cleanly.
For that purpose, a washing operation is applied on the substrate surface. Wet washing or dry washing is adopted in the washing operation. Examples of the wet washing include chemical methods, such as dissolving removal (elimination), oxidation decomposition, and surface layer etching, followed by washing with pure water after application of the chemical method. Furthermore, in addition to the chemical methods, physical methods can be performed as well. Examples thereof include brush washing, high-pressure water jet washing, and supersonic wave washing.
In the methods of the present invention, a metal organic compound is used. It is used after applying a solution, obtained by dissolving a metal organic compound in a solvent, on a substrate and drying.
The organic group(s) constituting the metal organic compound plays the role of isolating metal ions, to be the cores with each other, by the steric hindrance effect, so that the ions do not undergo aggregation, crystal growth, and powdering in forming an oxide by decomposition after application. As the above-mentioned organic group, any one capable of achieving the steric hindrance effect can be used.
Specific examples of the metal organic compound include an organic metal complex compound, a metal organic acid salt, and a metal alkoxide having 6 or more carbon atoms. The metal organic compounds can be used as a mixture of two or more kinds.
The organic metal complex is a compound constituted by coordination of an organic group(s) to a metal. Specific examples include a metal acetylacetonato.
The metal acetylacetonato is a metal complex formed by the bond of a metal to acetylacetone.
The metal acetylacetonato is not particularly limited, as long as the metal acetylacetonato of the targeted metal oxide becomes a solution by being dissolved in a solvent so as to be the metal oxide at the time of decomposition. As the metal, the metal which should be the component of the metal oxide to be obtained is selected. Specific examples of the metal include titanium, tin, indium, zirconium, zinc, cobalt, iron, and nickel. As the metal acetylacetonato, an acetylacetonato of these metals can be mentioned.
Moreover, the acetylacetonato can be an acetylacetonato salt. In the case of obtaining a composite metal oxide film, a mixture of acetylacetonato of the metal constituting the desired composite metal oxide film and another metal organic compound can be used.
The metal organic acid salt is a salt obtained by neutralizing various kinds of metal ions and various kinds of organic acids.
The organic acid is preferably a carboxylic acid, examples include an aliphatic carboxylic acid, an alicyclic carboxylic acid, and an aromatic carboxylic acid.
The aliphatic carboxylic acid preferably has 3 to 20 carbon atoms, such as monovaleic carboxylic acid, divaleic carboxylic acid, and polyvaleic carboxylic acid. The aliphatic group is preferably an alkyl group or an alkenyl group. These groups may have a substituent. In addition to an alkyl group, the substituent can be an alkyl ether group, an OH group, a halogen element, an amino group, or the like. Specific examples include 2-ethylhexanoic acid, caprylic acid, stearic acid, lauric acid, butyric acid, propionic acid, oxalic acid, citric acid, lactic acid, and ethylenediaminetetraacetic acid.
The alicyclic carboxylic acid has a COOH group as the substituent on an alicyclic hydrocarbon. An alkyl group can be another substituent. Specific examples include naphthenic acid.
The aromatic carboxylic acid has a COOH group as the substituent on an aromatic hydrocarbon. An alkyl group, an OH group, or the like can be another substituent. Specific examples include benzoic acid and salicylic acid.
As a metal constituting the metal organic acid salt, an alkali metal, an alkali earth metal, a transitional element, and an amphoteric element can be used. Specific examples of the metal include titanium, tin, lead, indium, zirconium, cobalt, iron, nickel, or the like.
In the case of obtaining a composite metal oxide, a mixture of organic acid salts of metals constituting the composite metal oxide, or a mixture of an organic acid metal salt and another organic metal compound is used. Accordingly, a composite metal oxide can be obtained.
The metal alkoxide is a compound with the hydrogen of a hydroxyl group in alcohols substituted by a metal.
As the metal alkoxy group, an alkoxy group, as an organic group having 6 or more (preferably 17 or less) carbon atoms, is used. In the case a metal alkoxide having 5 or less carbon atoms is used, for example, if isopropoxide of titanium is used, polycondensation occurs, while hydrolysis by the slight amount of water content generally existing in air, thereby becoming in the gel state. In that case, a result different from the decomposition by the laser irradiation is caused, and thus the object of the invention cannot be achieved.
Specific examples of the alkoxy group as an organic group having 6 or more carbon atoms include a 2-ethyl-1-hexanoyl group, a heptanoyl group, a 2-ethyl-1-heptanoyl group, an octanoyl group, a nonanoyl group, or the like.
As the metal constituting the metal alkoxide, titanium, indium, tin, zirconium, zinc, lead, cobalt, nickel, iron, or the like can be mentioned.
In the case of obtaining a composite metal oxide, a mixture of a metal alkoxide of a metal constituting the composite metal oxide, or a mixture of a metal alkoxide and another organic metal compound is used.
By dissolving the above-mentioned metal organic compound in a solvent, a metal organic compound solution is prepared. As to the amount of the solvent to be used, an amount capable of dissolving the metal organic compound is used.
The case of using a metal acetylacetonato will be explained as a specific example of an organic metal complex as the metal organic compound.
Metal acetylacetonatos have different solubilities in solvents. Since it should be dissolved homogeneously in a solvent in the methods of the present invention, an appropriate solvent can be selected. As the solvent, an organic solvent can be used. The organic solvent is one capable of dissolving a metal acetylacetonato. Examples of the solvents include hydrocarbons, which are non-polar solvents, such as hexane, octane, benzene, toluene, and tetralin. In addition to that, acetylacetone, alcohols, such as methanol, ethanol, and propanol; amines, pyridine, organic acids, such as acetic acid and propionic acid, and esters, such as butyl acetate, can be used as well. The organic solvents can be used alone or in combination of two or more, according to the kind of the metal acetylacetonato to be specifically used.
The metal concentration in the solvent can be determined according to the solubility of the metal acetylacetonato or the like. The metal concentration is generally 3 to 40% by weight, in terms of the weight of the metal acetylacetonato, and preferably 5 to 10% by weight. When the metal concentration is too small, it is not sufficient for production of a metal oxide film. On the other hand, when the concentration is too large, it is difficult to completely dissolve, and thus a sufficient result cannot be obtained. Generally, a necessary amount of a metal acetylacetonato is added into a solvent, and agitated sufficiently.
Preparation of the solution can be carried out by dissolving a metal acetylacetonato, preliminarily provided with a certain component composition, in a solvent, or a method of preliminarily preparing each solvent solution of various kinds of metal acetylacetonatos, and mixing the solvent solutions.
In the case of insufficient dissolution, a heating operation can be carried out. A solution accordingly obtained should have a specific property for the application on a substrate. For example, in the case of adopting a means of spin coating, since the solution needs to have a certain degree of viscosity, the viscosity of the solution can be adjusted by adding an appropriate amount of a polymer substance or the like, as a viscosity-adjusting agent.
When a metal organic acid salt is used as the metal organic compound, the solution thereof is prepared as follows.
In the case of dissolving each metal organic acid salt in a solvent, the solubility of the metal organic acid salts vary for different solvents.
Since the metal organic acid salt should be dissolved homogeneously in a solvent in the methods of the present invention, an appropriate solvent can be selected. As the solvent, an organic solvent can be used. The organic solvent should be capable of dissolving a metal organic acid salt. Examples of the solvent include hydrocarbons, which are non-polar solvents, such as hexane, octane, benzene, toluene, and tetralin. In addition to that, acetylacetone, alcohols, such as methanol, ethanol, and propanol; amines, pyridine, organic acids, such as acetic acid and propionic acid, and esters, such as butyl acetate, can be used as well. The organic solvents can be used alone or in combination of two or more, according to the kind of the metal organic acid salt to be specifically used.
The metal concentration in the solvent can be determined according to the solubility of the metal organic acid salt or the like. The metal concentration is generally 3 to 40% by weight, in terms of the weight of the metal organic acid salt, and preferably 5 to 10% by weight. When the metal concentration is too small, it is not sufficient for production of a metal oxide film. On the other hand, if the concentration is too large, it is difficult to completely dissolve, and thus a sufficient result cannot be obtained. Generally, a necessary amount of a metal organic acid salt is added into a solvent, and agitated sufficiently.
Preparation of the solution can be carried out by dissolving a metal organic acid salt, preliminarily provided with a certain component composition, in a solvent, or by a method of preliminarily preparing each solvent solution of various kinds of metal organic acid salts, and mixing the solutions containing the solvents.
In the case of insufficient dissolution, a heating operation can be carried out. A solution accordingly obtained should have a specific property for the application on a substrate. For example, in the case of adopting a means of spin coating, since the solution needs to have a certain degree of viscosity, the viscosity of the solution can be adjusted by adding an appropriate amount of a polymer substance or the like, as a viscosity-adjusting agent.
Metal alkoxides have different solubilities in solvents. Since it should be dissolved homogeneously in a solvent in the methods of the present invention, an appropriate solvent can be selected. As the solvent, an organic solvent can be used. The organic solvent should be capable of dissolving metal alkoxide. Examples of the solvent include hydrocarbons, which are non-polar solvents, such as hexane, octane, benzene, toluene, and tetralin. In addition to that, acetylacetone, alcohols, such as methanol, ethanol, and propanol; amines, pyridine, organic acids, such as acetic acid and propionic acid, and esters, such as butyl acetate, can be used as well. The organic solvents can be used alone or in combination of two or more, according to the kind of the metal alkoxide to be specifically used.
The metal concentration in the solvent can be determined according to the solubility of the metal alkoxide or the like. The metal concentration is generally 3 to 40% by weight, in terms of the weight of the metal alkoxide, and preferably 5 to 10% by weight. When the metal concentration is too small, it is not sufficient for production of a metal oxide film. On the other hand, if the concentration is too large, it is difficult to completely dissolve, and thus a sufficient result cannot be obtained. Generally, a necessary amount of a metal alkoxide is added into a solvent, and agitated sufficiently.
Preparation of the solution can be carried out by dissolving a metal alkoxide, preliminarily provided with a certain component composition, in a solvent, or a method of preliminarily preparing each solvent solution of various kinds of metal alkoxides, and mixing the solvent solutions.
In the case of insufficient dissolution, a heating operation can be carried out. A solution accordingly obtained should have a specific property for the application on a substrate. For example, in the case of adopting a means of spin coating, since the solution needs to have a certain degree of viscosity, the viscosity of the solution can be adjusted by adding an appropriate amount of a polymer substance or the like, as a viscosity-adjusting agent.
In obtaining an oxide film, a laser light of 400 nm or less wavelength is irradiated onto a substrate with a solution of a metal organic compound applied. A photosensitizer is preferably added into the solution of the metal organic compound, thereby absorption of the laser light can be improved, to have the wavelength of the irradiated laser light at 400 nm or less. The photosensitizer can be selected and used optionally from conventionally used photosensitizers, according to the wavelength. Specific examples thereof include an organic amine. Specific examples of the organic amine include monoethanol amine, diethanol amine, and triethanol amine.
When a solution of a metal organic compound is applied on the substrate, it is carried out as follows.
The solution of a metal acetylacetonato as the obtained organic metal complex compound, the organic metal acid salt solution, or the metal alkoxide solution, is applied on the support substrate, to form a layer on the substrate. As a means for applying these solutions onto the substrate, a means conventionally used for forming a thin film on a substrate can be optionally selected. Specifically, a solution application method can be used, and various conventionally known methods, such as a dipping (soaking) method, a spray method, a brush application method, and a spin coat method, can be used.
Then, the formed thin film-like coated (applied) layer is dried. The drying operation can be carried out by leaving the formed layer for a certain period of time in an atmosphere of about room temperature or warmer, or in a slightly heated atmosphere.
The specific procedure is as follows. The liquid film formed on the substrate is dried at a room temperature or under heating. For example, it can be carried out according to a method of raising the temperature to 150xc2x0 C. over 15 minutes in air, at a temperature-increase rate of 10xc2x0 C./min, maintaining at the same temperature for 15 minutes, and furnace-cooling. The thickness of the film formed on the substrate can finally be in the range of about 1 nm to 10 xcexcm.
The irradiation of the laser light of 400 nm or less wavelength can be carried out as follows.
A substrate is set in a substrate holder in air or an atmosphere-controllable chamber, so that a laser light is irradiated thereto, with a certain light intensity and repetition number.
The kind of the light source, the light intensity, the repetition rate (pulse or continuous), the substrate temperature, and the atmosphere can be selected optionally according to the kind of the metal organic compound to be the subject.
The above can be optionally selected in consideration of the physical properties, such as the absorption characteristics with respect to the thin film layer of the metal acetylacetonato solution as the organic metal complex and the metal organic acid salt solution.
A short-wavelength laser to be used in the present invention, does not have self-absorption by the use of an inert gas compound, which is unstable at the ground state. By changing the gas to be used, strong pulse lights of 400 nm or less can be obtained. They have a high repetition frequency, with a pulse width of several ns and a top output of several MW or more.
Examples of the light source used in the light irradiation include excimer lasers, such as an ultraviolet ray laser XeF (351 nm), XeCl (308 nm), KrF (248 nm), ArF (193 nm), and F2 (157 nm); and Ar ion laser (second higher harmonic wave: 257 nm), each of which has little heating effect.
Since the transmittance of the optical material is reduced according to shortening of the wavelength, a KrF (248 nm) laser is adequate as the light source for adopting a dioptric system using a lens.
The specific conditions can be mentioned as follows.
An ArF excimer laser (193 nm) light is irradiated, at a 1 to 20 Hz laser repetition number, and a laser fluence in the range of 10 to 70 mJ/cm2, for a period of time of about 3 to about 15 minutes. More specifically, an ArF excimer laser (193 nm) light is applied at 10 Hz and 50 mJ/cm2 for 5 minutes, or the like.
Generally, the laser light irradiation is carried out in air, but if a non-stoichiometric property exists in the metal oxide, control of the atmosphere, such as performing the irradiation in hydrogen, in nitrous oxide, in nitrogen, or in ozone, is required.
Accordingly, the applied metal-containing organic compound can be decomposed, as well as that a crystallized metal oxide thin film can be formed.
In the present invention, it is also effective to carry out the laser irradiation in a plurality of steps of at least two steps. One compound that cannot be decomposed in one step can be decomposed completely by carrying out the laser irradiation in a plurality of steps. The method of carrying out the irradiation in a plurality of steps, such as two steps, is particularly effective in the case of utilizing a metal organic acid salt as the metal organic compound. In decomposing the metal organic acid salt in a plurality of steps, a metal organic acid salt, which is stable and thus generally resists decomposition in one step, can be decomposed.
In carrying out the laser irradiation in a plurality of steps, it is particularly effective to irradiate with a weaker energy in the first step with respect to the subsequent step. This is effective because, if irradiation is carried out with a strong energy from the beginning, decomposition of the metal organic acid salt may not be done when a metal organic salt is used as the metal-containing organic compound. One reason decomposition may not be done as described above is considered to be the possibility of ablation of the metal organic acid salt as the raw material.
Because ablation may be caused by overly strong energy irradiation by a laser, a weak-output irradiation, or irradiation with the specimen maintained at an extremely low temperature, is effective in the first step.
As the reason decomposition is carried out preferably by irradiating with weak energy by a laser in the first step, and subsequently irradiating with energy (in particular, stronger energy), stabilization of the metal organic acid salt (such as iron 2-ethylhexanoate) and an increase of the interaction between iron 2-ethylhexanoate molecules and the substrate, according to elimination of the solvent in advance, in the first preliminary step, can be considered.
For example, it is presumed that, with the irradiation of the weak laser light in the first step in the plurality of laser light irradiation steps, the metal organic compound can be excited to a semi-stable state, and affinity of the metal organic compound (e.g. a metal organic acid salt) to the substrate may increase, to cause a certain kind of bond between them. According to that, it is expected that the metal organic compound can be effectively decomposed and converted to a metal oxide by the subsequent step of irradiation with the stronger laser light. Contrary to the above, in the case, for example, of a certain metal organic acid salt, when the compound is irradiated with the stronger laser light from the beginning without a preliminary irradiation with a weak laser light, the metal organic acid salt molecules may easily be evaporated (devolatilized), and no desirable oxide can result.
The energy irradiation by a laser according to the present invention can be preferably carried out by irradiating an energy of a degree that does not completely decompose the metal organic acid salt in the first step, and subsequently irradiating an energy of a degree capable of decomposing the metal organic acid salt.
Examples of the specific conditions of the laser irradiation can be mentioned as follows.
An ArF excimer laser (193 nm) is used for carrying out the first irradiation at 10 mJ/cm2 and 50 Hz for 30 seconds, and the subsequent irradiation at 50 mJ/cm2 and 10 Hz for 5 minutes.
An ArF excimer laser (193 nm) is used for carrying out the first irradiation at 10 mJ/cm2 and 50 Hz for 60 seconds, and the subsequent irradiation at 50 mJ/cm2 and 10 Hz for 5 minutes.
An ArF excimer laser (193 nm) is used for carrying out the first irradiation at 10 mJ/cm2 and 50 Hz for 30 seconds, and the subsequent irradiation at 50 mJ/cm2 and 10 Hz for 2.5 minutes.
According to the multi-step laser irradiation, production of a metal oxide film, which was difficult to be formed in the case of one-step decomposition (the case of a metal organic acid salt, particularly one-step irradiation with the stronger laser light), selective control of an oxide layer (in the case of irradiating a laser light to Ti (IV) 2-ethyl-1-hexanolate, a rutile phase is obtained by one-step irradiation, and an anatase phase is obtained by two-step irradiation), and synthesis of a composite oxide at a room temperature (a single phase of a PbTiO3 composite oxide can be obtained) are enabled.
According to the present invention, by the above-mentioned treatment, an organic metal complex or a metal organic acid salt, etc., which is the applied metal organic compound, can be decomposed, as well as that a crystallized oxide thin film comprising the metal of the above-mentioned metal organic compound, can be formed as a film on the substrate. Specifically, when titanium, tin, indium, zirconium, cobalt, iron, nickel, lead, or zinc is used as the metal, titanium oxide, tin oxide, indium oxide, zirconium oxide, cobalt oxide, iron oxide, nickel oxide, lead oxide, and zinc oxide can be obtained, respectively. In the case of using a plurality of metals as the raw material substance, a composite metal oxide can be obtained.
Confirmation of the metal oxide accordingly produced can be carried out by X-ray diffraction or the like. The metal oxide accordingly obtained can be used after separating it from the substrate.
In the formation of a metal oxide film according to the present invention, a patterning operation can be carried out at the same time. For example, in the case of forming a transparent conductive film in the field of microoptics or electronics, a thin film is formed only at the necessary parts, or a minute patterning, on the micron order, is carried out on the thin film surface. For example, patterning of a sol-gel thin film is carried out, in general, by a combination of lithography and etching with respect to a metal oxide after the final heat treatment.
According to the present invention, by the irradiation of a laser light of a 400 nm or less wavelength with respect to a thin film layer of a metal-containing organic compound on a substrate, a metal oxide insoluble with a solvent can be obtained directly.
By ultraviolet-ray irradiation to an applied film through a mask, and eliminating the non-irradiated part by a solvent, a minute patterning can be carried out in the laser film formation process.
The specific operation is as follows.
In a pattern-forming operation of a metal oxide according to the present invention, one selected from the group consisting of an organic metal complex, a metal organic acid salt, and a metal alkoxide, as the metal organic compound to be provided on a substrate, is dissolved in a solvent so as to form a thin film layer on the substrate, and a laser light of a 400 nm or less wavelength is irradiated thereto according to a certain pattern shape or through a certain mask pattern. The light-irradiation condition is the same as the above-mentioned case of irradiation for producing a metal oxide.
Since a thin film layer comprising a metal organic compound becomes a metal oxide in the irradiated part subject to a laser light irradiation of a 400 nm or less wavelength, the solubility with respect to the above-mentioned organic solvent is remarkably lowered. According to a developing process using the above-mentioned organic solvent in this state, the non-irradiated part can be dissolved and eliminated selectively, so that only the irradiated part can remain, so as to form a resist pattern accurately reproducing the original picture. The developing process can be carried out, in general, by the conventionally and commonly used dipping method, but the brush-out method and the blowing method can be used as well.
As the above-mentioned organic solvent, in addition to the solvents used in dissolving a metal organic compound, for example, aromatic hydrocarbons, such as benzene, toluene, xylene, and ethyl benzene; aliphatic halogenated hydrocarbons, such as methylene dichloride, ethylene dichloride, chloroform, and carbon tetrachloride; and aromatic halogenated hydrocarbons, such as monochlorobenzene, can be used in combination.
Since a metal oxide pattern accordingly formed has high chemical durability and excellent dry-etching durability, a substrate can be applied with an etching treatment with high accuracy by using the resist pattern as a mask. For the etching treatment of the substrate, a dry etching treatment can be preferably used. Accordingly, a minute pattern with a high aspect ratio can be formed easily with high resolution.
According to the present invention, a novel method for forming a crystalline metal oxide thin film by applying a solution containing a metal organic compound onto a substrate, and irradiating with laser light of 400 nm or less wavelength, was enabled. Moreover, by irradiating a laser light to an applied film through a mask, and thereafter eliminating the non-irradiated part by a solvent, a minute patterning can be obtained.
According to the method of the present invention, unlike the conventional methods, a targeted metal oxide which is formed on a substrate can be obtained, without a step of heat treatment at a high temperature. The metal oxide formed on the substrate is produced according to the production process without including a step of high-temperature heating. Accordingly, for example, in the case of a metal oxide formed on a silicon substrate, one without silicon deterioration or reaction among the laminated films, can be obtained. Moreover, in the case of PZT, which is expected as a dielectric memory, one without reaction of the PbO component with the silicon substrate or lowering of the dielectric characteristics, can be obtained. Furthermore, in the case of a transparent conductive film, such as indium oxide, since the film is formed at a low temperature, one having good characteristics for use as an electrode of photonics or electronics devices related to a light, such as a liquid crystal display board, a plasma display panel, and a solar battery, can be obtained.
Moreover, according to the plural-stage laser light irradiation, a metal oxide film, which cannot be obtained by one step, can be obtained, as well as that selective control of a specific oxide phase can be enabled, and thus synthesis of a composite oxide can be enabled at a room temperature.
The present invention is described in more detail, based on the following examples, but the invention is not limited to those.

Method for producing a metal oxide and method for forming a minute pattern

Agency of Industrial Science and Technology