Patents by Inventor Shinichi Tachi

Shinichi Tachi has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 5643473
    Abstract: A dry etching method is disclosed, in which the pressure of etching gas in a reaction chamber, the bias voltage applied to article to be etched, and the temperature of the article to be etched object are set so that the etching rate for the article to be etched is greater than 0.2 .mu.m/min, a ratio of the length of side etching in the article to be etched to the depth of etching therein is less than 1/100, and a ratio of the etching rate for the article to be etched to the etching rate for a mask formed thereon is greater than 10. Thus, the dry etching method can satisfy three requirements (that is, a high etching rate, a high selection ratio and marked anisotropy in etching) at the same time, although conventional dry etching methods can satisfy only two of three requirements.
    Type: Grant
    Filed: May 30, 1995
    Date of Patent: July 1, 1997
    Assignee: Hitachi, Ltd.
    Inventors: Shinichi Tachi, Kazunori Tsujimoto, Sadayuki Okudaira, Kiichiro Mukai
  • Patent number: 5499207
    Abstract: With recent decreases in the size of semiconductor memories, isolation problems typically arise during fabrication of a capacitor for a high-capacity semiconductor memory device. To overcome this, arrangements are provided to improve the isolation between capacitor elements even if those elements are extremely close together. For example, if a material such as platinum is used as a capacitor bottom electrode, a thin layer of titanium oxide can be deposited before forming the platinum, to provide a structure in which the titanium oxide is on the bottom portion of the trench. A high-dielectric-constant insulator is then formed over that structure by the Chemical Vapor Deposition. The high-dielectric-constant insulator has a composition which satisfies the stoichiometric composition over the platinum and which has more titanium atoms than those of the stoichiometric composition on the trench bottom.
    Type: Grant
    Filed: July 28, 1994
    Date of Patent: March 12, 1996
    Assignee: Hitachi, Ltd.
    Inventors: Hiroshi Miki, Yuzuru Ohji, Shinichi Tachi
  • Patent number: 5474650
    Abstract: A method and apparatus for dry etching changes at least one of the effective pumping speed of a vacuum chamber and the gas flow rate to alter the processing of an etching pattern side wall of a sample between first and second conditions. The first and second conditions include the presence or absence of a deposit film, or the presence, absence or shape of a taper angle. Various parameters for controlling the first and second conditions are contemplated.
    Type: Grant
    Filed: September 7, 1994
    Date of Patent: December 12, 1995
    Assignee: Hitachi, Ltd.
    Inventors: Takao Kumihashi, Kazunori Tsujimoto, Shinichi Tachi
  • Patent number: 5409562
    Abstract: In microwave dry etching, the substrate/resist etching selectivity is controlled by adding a material, such as an additional gas, to the reaction gas plasma that heats the substrate with greater energy transfer efficiency than the resist. For example, a W substrate having a resist is etched with an SF.sub.6 reaction gas to which is added an Xe gas for generating incident ions that impinge the substrate with greater energy transfer than they do the resist. This produces a greater hot spot temperature for the substrate as compared with the resist to increase the substrate/resist etching selectivity. The hot spot temperature difference can be further effected by applying a bias potential to the substrate during the etching with an RF power supply.
    Type: Grant
    Filed: July 31, 1992
    Date of Patent: April 25, 1995
    Assignee: Hitachi, Ltd.
    Inventors: Takao Kumihashi, Kazunori Tsujimoto, Shinichi Tachi
  • Patent number: 5368685
    Abstract: At an effective exhaust speed of 1200 liter/s, high frequency power with power surface density of 4.5 W/cm.sup.2 is made to discharge high density plasma, thereby carrying out dry etching. With a gas residence time of 100 ms or less, a gas flow rate controller is provided which has a response time substantially equal to the gas residence time. Etching can be performed at high speed with deposit reaction restrained and high ion current density. Because of the enhanced ion current density, etching providing high selectivity can be made with lowered ion energy. The time required for gas exchange in time modulation etching, multi-step etching and attachment/removal of electrostatic adsorption can be shortened to improve the etching throughput.
    Type: Grant
    Filed: March 24, 1993
    Date of Patent: November 29, 1994
    Assignee: Hitachi, Ltd.
    Inventors: Takao Kumihashi, Kazunori Tsujimoto, Shinichi Tachi
  • Patent number: 5354416
    Abstract: Etching of an article is carried out by maintaining the article at a temperature at which the vapor pressure of etching gas molecules becomes equal to or higher than the pressure of etching gas and the vapor pressure of neutral radicals contained in a plasma becomes equal to or lower than the pressure of an etching gas. An etching pattern with a substantially vertical side profile and extremely small in dimensional shift from the mask can be formed at high precision.
    Type: Grant
    Filed: April 2, 1990
    Date of Patent: October 11, 1994
    Inventors: Sadayuki Okudaira, Kazunori Tsujimoto, Shinichi Tachi
  • Patent number: 5354418
    Abstract: A method and apparatus for dry etching changes at least one of the effective pumping speed of a vacuum chamber and the gas flow rate to alter the processing of an etching pattern side wall of a sample between first and second conditions. The first and second conditions include the presence or absence of a deposit film, or the presence, absence or shape of a taper angle. Various parameter for controlling the first and second conditions are contemplated.
    Type: Grant
    Filed: January 3, 1994
    Date of Patent: October 11, 1994
    Assignee: Hitachi, Ltd.
    Inventors: Takao Kumihashi, Kazunori Tsujimoto, Shinichi Tachi
  • Patent number: 5343353
    Abstract: A microminiature, large capacitor for a semiconductor memory is formed from a raw material compound of plural different kinds of metal atoms for deposition, irrespective of the material, temperature and surface condition of a substrate, thereby forming a thin dielectric film having uniform characteristics not affected by the interface even though the film is made as thin as approximately 0.1 .mu.m. The microminiature large capacitance capacitor has a capacitance unaffected by an oxide existing at the interface between a ferroelectric and electrodes without using precious metals such as platinum having the least degree of freedom in deposition of thin films and microminiature processing. The ferroelectric thin film is deposited using an organic metal comprising a plurality of kinds of metal elements in conformity with the composition of a desired dielectric. As electrodes for use in forming a capacitor, a substance exhibiting conductivity after oxidation is preferably employed.
    Type: Grant
    Filed: August 17, 1992
    Date of Patent: August 30, 1994
    Assignee: Hitachi, Ltd.
    Inventors: Hiroshi Miki, Yuzuru Ohji, Shinichi Tachi, Keiichi Kanehori
  • Patent number: 5318667
    Abstract: A method and apparatus for dry etching changes at least one of the effective pumping speed of a vacuum chamber and the gas flow rate to alter the processing of an etching pattern side wall of a sample between first and second conditions. The first and second conditions include the presence or absence of a deposit film, or the presence, absence or shape of a taper angle. Various parameter for controlling the first and second conditions are contemplated.
    Type: Grant
    Filed: March 18, 1993
    Date of Patent: June 7, 1994
    Assignee: Hitachi, Ltd.
    Inventors: Takao Kumihashi, Kazunori Tsujimoto, Shinichi Tachi
  • Patent number: 5242539
    Abstract: A plasma treatment method and apparatus utilize various gas inlet and outlet structure arrangements to optimize treatment characteristics for a semiconductor wafer. A buffer zone is created between gas inlets and the discharge zone of the vacuum treatment chamber to enhance uniformity of gas flow. The evacuation arrangement enables reactant gas to be exhausted uniformly to reduce gas residence time below a threshold while maintaining optimum flow rates and etch uniformity at low effective exhaust speeds.
    Type: Grant
    Filed: March 27, 1992
    Date of Patent: September 7, 1993
    Assignee: Hitachi, Ltd.
    Inventors: Takao Kumihashi, Kazunori Tsujimoto, Shinichi Tachi, Masafumi Kanetomo, Junichi Kobayashi, Tatehito Usui, Nobuyuki Mise
  • Patent number: 5147500
    Abstract: A dry etching method is disclosed, in which the pressure of etching gas in a reaction chamber, the bias voltage applied to article to be etched, and the temperature of the article to be etched object are set so that the etching rate for the article to be etched is greater than 0.2 .mu.m/min, a ratio of the length of side etching in the article to be etched to the depth of etching therein is less than 1/100, and a ratio of the etching rate for the article to be etched to the etching rate for a mask formed thereon is greater than 10. Thus, the dry etching method can satisfy three requirements (that is, a high etching rate, a high selection ratio and marked anisotropy in etching) at the same time, although conventional dry etching methods can satisfy only two of three requirements.
    Type: Grant
    Filed: October 10, 1990
    Date of Patent: September 15, 1992
    Assignee: Hitachi, Ltd.
    Inventors: Shinichi Tachi, Kazunori Tsujimoto, Sadayuki Okudaira, Kiichiro Mukai
  • Patent number: 4992136
    Abstract: An article to be etched is contacted with a plasma of a mixed gas containing an etching gas and a film forming gas or a surface modification gas at a low temperature to effect the dry etching of the article, whereby the selectivity of etching can be made very high and the inclination angle of the side wall of pattern can be controlled at a desired level.
    Type: Grant
    Filed: July 25, 1988
    Date of Patent: February 12, 1991
    Assignee: Hitachi, Ltd.
    Inventors: Shinichi Tachi, Kazunori Tsujimoto, Sadayuki Okudaira
  • Patent number: 4986877
    Abstract: A first etching for large side etching is conducted while maintaining the temperature of an article to be etched at a first temperature, and a second etching for small side etching is then conducted while maintaining the article to be etched at a second temperature lower than the first temperature. This enables the formation of various patterns in which the upper part of the sidewall is inclined at an angle smaller than that of the lower part of the sidewall.
    Type: Grant
    Filed: July 25, 1988
    Date of Patent: January 22, 1991
    Assignee: Hitachi, Ltd.
    Inventors: Shinichi Tachi, Kazunori Tsujimoto, Sadayuki Okudaira
  • Patent number: 4985114
    Abstract: A dry etching method including the steps of introducing etching and deposition gases alternately into a reaction chamber at predetermined time intervals, etching the exposed surface of an article to be etched and applying deposition to the surface film thereof alternately by making plasma generated by applying power to the etching and deposition gases introduced into the reaction chamber come in contact with the article to be etched in the reaction chamber in order to etch the surface, is characterized in that the power is applied after the passage of predetermined time from the start of the introduction of the deposition gas and before the etching gas is introduced and cut off when the introduction of the etching gas is suspended.
    Type: Grant
    Filed: October 6, 1989
    Date of Patent: January 15, 1991
    Assignee: Hitachi, Ltd.
    Inventors: Sadayuki Okudaira, Hiroshi Kawakami, Tokuo Kure, Kazunori Tsujimoto, Shinichi Tachi
  • Patent number: 4956043
    Abstract: A dry etching apparatus is disclosed, in which the temperature of an article to be etched, placed on a wafer table, is controlled by a liquefied gas and a heater and the height of the surface of the liquefied gas can be varied arbitrarily. This apparatus enables the controlling of the temperature of the article to be done with a high accuracy over a wide range of low levels. Therefore, a low-temperature dry etching operation, which cannot otherwise be attained by a conventional apparatus of this kind, can be carried out.
    Type: Grant
    Filed: May 10, 1988
    Date of Patent: September 11, 1990
    Assignee: Hitachi, Ltd.
    Inventors: Masafumi Kanetomo, Shinichi Tachi, Kazunori Tsujimoto, Kiichiro Mukai, Takahiro Daikoku, Shigekazu Kieda, Keijiro Shindo, Kenshiro Tamura
  • Patent number: 4943344
    Abstract: A deep trench is formed by carrying out etching by using an etching gas free of carbon and silicon, which contains at least one member selected from the group consisting of fluorine, chlorine and bromine, while maintaining an article to be etched at such a temperature that the reaction probability between silicon and fluorine, chlorine or bromine contained in the etching gas is less than 1/10 of the reaction probability at 20.degree. C. According to this method, a deep trench having a very narrow width and a large aspect ratio, which cannot be formed according to the conventional method, can be formed very promptly with much reduced side etching.
    Type: Grant
    Filed: June 6, 1989
    Date of Patent: July 24, 1990
    Assignee: Hitachi, Ltd.
    Inventors: Shinichi Tachi, Kazunori Tsujimoto, Sadayuki Okudaira, Kiichiro Mukai
  • Patent number: 4911812
    Abstract: The present invention relates to a plasma treating method and apparatus therefor. The plasma treating method comprises the steps of forming a treating gas into a plasma under reduced pressure, utilizing the plasma to treat a specimen cooled to a low temperature less than 0.degree. C.
    Type: Grant
    Filed: October 17, 1988
    Date of Patent: March 27, 1990
    Assignee: Hitachi, Ltd.
    Inventors: Katsuyoshi Kudo, Yoshinao Kawasaki, Minolu Soraoka, Tsunehiko Tsubone, Kazunori Tsujimoto, Shinichi Tachi, Saadyuki Okudaira
  • Patent number: 4857137
    Abstract: An ion beam is allowed to hit the surface of a target and the resulting forward scattered particle beam is then allowed to hit the surface of a workpiece, thereby etching or modifying the surface of the workpiece or depositing a film on the surface of the workpiece. By bombardment of ions with the target, electric charges possessed by the ion beam are lost, and only the thus neutralized forward scattered particle beam is allowed to hit the surface of the workpiece, and thus the said surface treatment can be carried out without any electrically charging trouble.
    Type: Grant
    Filed: February 2, 1987
    Date of Patent: August 15, 1989
    Assignee: Hitachi, Ltd.
    Inventors: Shinichi Tachi, Sadayuki Okudaira, Kazunori Tsujimoto, Kiichiro Mukai
  • Patent number: 4529476
    Abstract: A dry-etching gas suitable for selective etching of silicon nitride and a process for selectively dry-etching silicon nitride with the dry-etching gas are disclosed. Silicon nitride can be dry-etched with a higher selectivity or at a higher etching rate than silicon dioxide and silicon, and a process for fabricating semi-conductor devices can be simplified and devices with a novel structure can be realized.
    Type: Grant
    Filed: June 1, 1984
    Date of Patent: July 16, 1985
    Assignees: Showa Denko K.K., Hitachi, Ltd.
    Inventors: Yoshifumi Kawamoto, Hiroshi Kawakami, Tokuo Kure, Shinichi Tachi, Norikazu Hashimoto, Tsuyoshi Takaichi
  • Patent number: 4406733
    Abstract: In a dry etching method of etching Si, PF.sub.5 -gas is used as a source gas for plasma etching and reactive ion beam etching. The substrate can be etched at a higher rate as compared with the plasma etching in which CF.sub.4 -gas is used as the source gas.
    Type: Grant
    Filed: December 21, 1982
    Date of Patent: September 27, 1983
    Assignee: Hitachi, Ltd.
    Inventor: Shinichi Tachi