Patents Examined by Felisa C. Garrett
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Patent number: 5932003Abstract: The present invention relates to a method of producing a recrystallized-material-member by melting a given zone of a crystalline-material-member and moving the molten zone continuously along the crystalline-material-member to recrystallize a desired region of the crystalline-material-member, wherein dimension of the molten zone of the crystalline-material-member is controlled to be constant and/or quality of crystal of the recrystallized-material-member is controlled to be uniform.Type: GrantFiled: January 13, 1997Date of Patent: August 3, 1999Assignees: Mitsubishi Denki Kabushiki Kaisha, Dainippon Screen Mfg. Co., Ltd.Inventors: Hideo Naomoto, Akihiro Takami, Takashi Ishihara, Takashi Ito, Takatoshi Chiba, Eiichi Tamaki
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Patent number: 5911823Abstract: A method for pulling a <110> single-crystal silicon aims at preventing the crystal from being cut in diameter-reducing and suppress the increase in cost due to the cut prevention to the minimum. In the step for forming a diameter-reduced portion performed prior to the step for growing a <110> single-crystal silicon by the Czochralski method, a magnetic field having a strength of 500 gauss or more is applied and while suppressing a melt surface vibration and temperature variation, the crystal diameter is reduced to 2.00 mm or smaller.Type: GrantFiled: December 10, 1996Date of Patent: June 15, 1999Assignee: Komatsu Electronics Metals Co., Ltd.Inventors: Kouji Sonoda, Toshio Mimura
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Patent number: 5861337Abstract: A method for manufacturing a semiconductor device including preparing a multi-chamber system having at least first and second chambers, the first chamber for forming a film and the second chamber for processing an object with a laser light; processing a substrate in one of the first and second chambers; transferring the substrate to the other one of the first and second chambers; and processing the substrate in the other one of the chambers, wherein the first and second chambers can be isolated from one another by using a gate valve.Type: GrantFiled: June 2, 1995Date of Patent: January 19, 1999Assignee: Semiconductor Energy Laboratory Co., Ltd.Inventors: Hongyong Zhang, Naoto Kusumoto
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Patent number: 5853480Abstract: An apparatus and a method for fabricating a single-crystal semiconductor by means of a CZ method are provided for improving the quality through modification of the thermal cycle of a pulled single-crystal semiconductor. The apparatus includes a ring-shaped after heater which is capable of elevation. The method decreases the temperature gradient to smaller than 20.degree. C./cm, and preferably under 15.degree. C./cm, when the pulled single-crystal semiconductor is cooled from 1200.degree. C. to 1000.degree. C. The after heater therefore heats the single-crystal semiconductor where there is a temperature of 100.degree.-300.degree. C. lower than the range of 1200.degree.-1000.degree. C. A thermal baffle (or shield) is provided to retain a temperature gradient of larger than 20.degree. C./cm when the single-crystal semiconductor is within the temperature range between the melting point and 1250.degree. C.Type: GrantFiled: February 18, 1997Date of Patent: December 29, 1998Assignee: Komatsu Electronic Metals Co., Ltd.Inventors: Toshimichi Kubota, Toshiro Kotooka, Makoto Kamogawa
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Patent number: 5817170Abstract: A process for producing a ferroelectric lead zirconate titanate dielectric for a semiconductor device by applying a lead titanate seeding layer to a substrate before applying the lead zirconate titanate film, and a semiconductor device produced in accordance with the process. The lead titanate seeding layer allows the subsequent lead zirconate titanate to be annealed at a significantly lower seeding temperature, to lessen interdiffusion among the films, electrodes and substrate and to lessen thermal stresses.Type: GrantFiled: August 29, 1994Date of Patent: October 6, 1998Assignees: Ceram Incorporated, Sharp Kabushiki Kaisha, Virginia Tech Intellectual Properties, Inc.Inventors: Seshu B. Desu, Chi Kong Kwok
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Patent number: 5766348Abstract: A rotating head (11) for crystal pulling systems (1) according to Czochralski has a reference platform (16) which is able to rotate around a vertical rotation axis (A--A) with a vertical feed-through opening (25) for a pulling cable (13) that can be wound up and a drive assembly (23) for driving a shaft (22). A winding drum (15) with a helical winding groove (29) for the pulling cable is located on this shaft in a fixed manner so it cannot rotate, but can be moved axially. In order to avoid abrasion and contamination and to accurately guide the cable (13), a helical guiding element (30) with the same pitch as the winding groove is located on the shaft (22) at a location remote from the vertical rotation axis (A--A). This guiding element is able to rotate with the shaft. The guiding element works together with a guiding nut (31) in such a way that the part of the cable (13) which faces tangentially away from the winding drum (15) is directly guided in the vertical rotation axis (A--A).Type: GrantFiled: March 24, 1997Date of Patent: June 16, 1998Assignee: Leybold AktiengesellschaftInventors: Winfried Schulmann, Franz Thimm, Helmut Kaiser
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Patent number: 5733371Abstract: According to the present invention, in the growth of an oxide single crystal or a compound semiconductor single crystal such as GaAs single crystal by the CZ method or LEC method, the tendency of concave solid-liquid interface shape at the periphery of the growing crystal can be suppressed to prevent polycrystallization without localized heating of the solid-liquid interface, while controlling the diameter of the growing crystal even when using a crucible with a larger diameter, thus improving the yield of crystal on a commercial scale. In the invention, the end of a cylindrical body having an inner diameter of larger than the predetermined diameter of straight part of the growing crystal is immersed in the raw material melt or liquid encapsulant and the crystal is pulled while preventing the shape of the solid-liquid interface from becoming concave by controlling the rotation rate of at least one of a crucible holding the raw material melt, the growing crystal and cylindrical body.Type: GrantFiled: March 15, 1996Date of Patent: March 31, 1998Assignee: Sumitomo Electric Industries, Ltd.Inventors: Katsushi Hashio, Shin-ichi Sawada, Masami Tatsumi
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Patent number: 5725672Abstract: Described is a method for depositing from the vapor phase a chemical species into the form of a thin solid film material which overlays a substrate material. The deposition process consists of three steps: (1) synthesis of depositing species, (2) transport of said species from site of synthesis to a prepared substrate material, and (3) condensation and subsequent film growth. The transport step is achieved by admixing small concentrations of the depositing species into the flow of a high speed jet of an inert carrier gas. This jet impinges on the substrate's surface and thereby convects the depositing species to this surface where condensation occurs. Since the gas mixture is at fairly high pressure, the deposition is achieved in a simple flow apparatus rather than in the high vacuum systems required of other methods. Also this transport technique allows the chemical and/or physical phenomena utilized in the depositing species synthesis step to be isolated from the actual condensation reaction.Type: GrantFiled: January 24, 1995Date of Patent: March 10, 1998Assignee: Jet Process CorporationInventors: Jerome J. Schmitt, Bret L. Halpern
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Patent number: 5702523Abstract: A rotating head (11) for crystal pulling systems (1) according to Czochralski has a reference platform (16) which is able to rotate around a vertical rotation axis (A--A) with a vertical feed-through opening (25) for a pulling cable (13) that can be wound up and a drive assembly (23) for driving a horizontal shaft (22). A winding drum (15) with a helical winding groove (29) for the pulling cable is located on this shaft in a fixed manner so it cannot rotate, but can be moved axially. In order to avoid abrasion and contamination and to accurately guide the cable (13), a helical guiding element (30) with the same pitch as the winding groove is located on the horizontal shaft (22) at a location remote from the vertical rotation axis (A--A). This guiding element is able to rotate with the horizontal shaft.Type: GrantFiled: August 31, 1994Date of Patent: December 30, 1997Assignee: Leybold AktiengesellschaftInventors: Winfried Schulmann, Franz Thimm, Helmut Kaiser
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Patent number: 5641354Abstract: A crystal puller cell (18) provides a low particulate environment for an individual crystal puller (28). The airflow within each cell is adjustable so that a particulate level appropriate to the activity within the cell is maintained, thereby avoiding the cost of maintaining an entire growing hall (10) at a constant high level of cleanliness. Each cell includes a multilevel floor (46) that includes an operator floor (48) and a maintenance floor (52). A door (62) at the maintenance floor level opens onto a maintenance aisle used to service the machines. A door (64), at the operator floor level, opens onto a clean aisle for transporting raw material and finished product. The cell walls can include magnetic shielding if a magnetic growing process is used to reduce exposure of operators and other machines to intense magnetic fields.Type: GrantFiled: July 10, 1995Date of Patent: June 24, 1997Assignee: SEH America, Inc.Inventors: Kazuo Sakauchi, Yoshihiro Hirano, Akira Uchikawa
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Patent number: 5635244Abstract: Disclosed is a wafer clamp which holds a wafer in place during chemical vapor deposition processes. The wafer clamp includes (1) a clamp body having an inner facing portion and an outer facing portion; and (2) an overhang member attached to and extending inwardly from the inner facing portion of the clamp body. The clamp is designed such that when it holds the wafer, the overhang member extends over the wafer's peripheral region and is separated from that peripheral region by at least a predefined distance. The peripheral region is a region on the wafer's upper face that resides near the perimeter of the upper face. The predefined distance is chosen such that during deposition, a layer of material does not contact both the wafer face and the overhang member. The predefined distance is at least about 100 times the thickness of the layer of material.Type: GrantFiled: August 28, 1995Date of Patent: June 3, 1997Assignee: LSI Logic CorporationInventors: Mark I. Mayeda, Wilbur G. Catabay, Joe W. Zhao
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Patent number: 5630878Abstract: A liquid flow meter is connected in series with a vaporizer having a vaporizing function and a flow rate-adjusting function and vaporizing a liquid material supplied through said liquid flow meter to compare a flow rate detected by the liquid flow meter with a set value, whereby controlling a quantity of liquid material introduced into a vaporizing chamber provided in said vaporizer on the basis of this comparison result, and thus a flow rate of vaporized gas can be always stably controlled in high-speed response.Type: GrantFiled: February 13, 1995Date of Patent: May 20, 1997Assignee: STEC Inc.Inventors: Hideaki Miyamoto, Kohichi Ishikawa, Takeshi Kawano
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Patent number: 5628882Abstract: System and method for plasma-assisted deposition of optically transparent, crystalline chromium/carbon/fluorine films are described using a chromium metal source and an argon/fluorocarbon plasma. The films were optically transparent to the unaided eye. Characterization of the material by electron diffraction showed the chromium/carbon/fluorine material to be crystalline.Type: GrantFiled: February 17, 1995Date of Patent: May 13, 1997Assignee: The United States of America as represented by the Secretary of the Air ForceInventors: Matthew J. O'Keefe, J. Michael Rigsbee
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Patent number: 5626670Abstract: A method for developing large area highly oriented polycrystalline ferroelectric thin films using spin-on sol-gel deposition and laser crystallization techniques that allow for precise control of temperature distribution. The present invention improves quality, reliability, performance and cost effective production of ferroelectric non-volatile random access memory (FNVRAM) on thermally sensitive silicon and gallium arsenide semiconductor substrates compatible with very large scale integrated circuit technologies. The method is time effective, as crystallization is performed in three seconds as compared to thirteen hours in a conventional furnace for 1 cm.times.1 cm wafer. In addition, crystallization of the film is further achieved without exposing the underneath device structure to detrimental high temperature annealing conditions.Type: GrantFiled: October 3, 1994Date of Patent: May 6, 1997Assignee: American Research Corporation of VirginiaInventors: Usha Varshney, Angus I. Kingon
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Patent number: 5627109Abstract: A sapphire wafer is sliced off parallel to a plane "a" {1120} so that patterns on its top surface are rectangular in shape as defined by an axis "c" (0001) and an axis "m" (1010). The sapphire wafer is fixed on a table. A scriber blade that is coated with synthetic diamond scribes the surface of the sapphire wafer so that scribe lines are formed in a checkered pattern. One of the scribe lines is inclined from axis "c" (001) by 20 to 70 degrees in a clockwise direction and the other scribe line is inclined from the axis "c" (001) by 20 to 70 degrees in a counterclockwise direction. After scribing, pressure is applied by a roller along the scribe lines so as to cause the sapphire wafer to break into a sapphire chip. The yield of sapphire chips is increased by the use of this method because chipping is less likely to occur.Type: GrantFiled: September 15, 1995Date of Patent: May 6, 1997Inventors: Michinari Sassa, Norikatsu Koide
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Patent number: 5620511Abstract: Disclosed in this invention is a method of preparing a whisker-preform comprising the steps of (a) uniformly dispersing a mixture of silicon microparticles and carbon fibers in the ratio of 4:1 to 8:1 into aluminium alkoxide solution; (b) filtering the dispersion obtained in step (a), dehydrating the filtered material, forming and drying the dehydrated material; and (c) heating the material dried in step (b) at a temperature in the range of 300.degree. to 400.degree. C.Type: GrantFiled: November 27, 1995Date of Patent: April 15, 1997Assignee: Hyundai Motor CompanyInventors: Junsu Kim, Bumgoo Chung
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Patent number: 5618345Abstract: A self-supporting thin film of silicon single crystal is produced essentially by the steps of implanting boron ions in a silicon single crystal substrate from one major surface thereof to form a high impurity concentration layer having a high boron concentration in the substrate; heating the silicon single crystal substrate formed with the high impurity concentration layer in an atmosphere containing oxygen to form an oxide film on the surface of the single crystal substrate and make the high impurity concentration layer resistant to etching; masking all of the oxide film surface other than that at the center region on the surface opposite from that implanted with boron ions and then exposing the high impurity concentration layer by high-speed mask etching followed by selective etching; and removing the oxide film.Type: GrantFiled: March 14, 1995Date of Patent: April 8, 1997Assignee: Agency of Industrial Science & Technology, Ministry of International Trade & IndustryInventors: Kazuo Saitoh, Hiroaki Niwa, Setsuo Nakao, Soji Miyagawa
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Patent number: 5616180Abstract: Apparati and methods for varying the flux of a molecular beam emanating from an effusion cell are disclosed. The apparatus includes a means for controllably adjusting the angular distribution of a molecular field effusing from a source material within the effusion cell, therein adjusting the flux of the beam. The method herein disclosed, with respect to the related apparati, including the step of selectively altering the angular distribution of an effusing molecular field, produced by a heated source material, which comprises the molecular beam, thereby varying the flux of the beam.Type: GrantFiled: December 22, 1994Date of Patent: April 1, 1997Assignee: Northrop Grumman CorporationInventors: Myung B. Lee, Jari Vanhatalo
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Patent number: 5611857Abstract: A process and apparatus for producing silicon single crystals with excellent dielectric strength of gate oxide films by adjusting the temperature gradient of the pulled-up silicon single crystal without loss of its rate of pulling. The process of producing silicon single crystals by pulling up the single crystal from a melt of material of the single crystal imposes a certain average temperature gradient on the grown single crystal while it is still at high temperature. The apparatus is provided with a heating element outside a crucible and pulling shaft with which a single crystal is pulled up from the melt of the material in the crucible. The ratio of length h of the heating element to the inside diameter .phi. of the crucible is adjusted so as to be between 0.2 and 0.8 whereby the temperature gradient can be maintained below 2.5.degree. C./mm.Type: GrantFiled: June 7, 1995Date of Patent: March 18, 1997Assignee: Sumitomo Sitix CorporationInventors: Yoshihiro Akashi, Kaoru Kuramochi, Setsuo Okamoto, Yasuji Tsujimoto, Makoto Ito
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Patent number: 5580381Abstract: A crystal forming method comprises disposing, on a surface of a substrate or in recessed portion formed in the substrate having a surface with a low nucleation density, primary seed having a sufficient small volume to singly aggregate and a rectangular prismatic or cubic shape in which all the sides and the bottom are surrounded by an insulator in contact therewith; performing heat treatment for aggregating the primary seed to form monocrystalline seed crystal having controlled plane orientation and in-plane orientation; and selectively growing monocrystal by crystal growth treatment using the seed crystal as starting point.Type: GrantFiled: November 3, 1995Date of Patent: December 3, 1996Assignee: Canon Kabushiki KaishaInventor: Kenji Yamagata