Patents by Inventor Yukihiro Utsuno

Yukihiro Utsuno 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).

  • Publication number: 20050224866
    Abstract: After an ONO film in which a silicon nitride film (22) formed by a plasma nitriding method using a plasma processor having a radial line slot antenna is sandwiched by silicon oxide films (21), (23), a bit line diffusion layer (17) is formed in a memory cell array region (11) by an ion implantation as a resist pattern (16) taken as a mask, then lattice defects are given to the silicon nitride film (22) by a further ion implantation. Accordingly, a highly reliable semiconductor memory device can be realized, in which a high quality nitride film is formed in a low temperature condition, in addition, the nitride film can be used as a charge trap film having a charge capture function sufficiently adaptable for a miniaturization and a high integration which are recent demands.
    Type: Application
    Filed: February 25, 2005
    Publication date: October 13, 2005
    Applicant: FASL LLC
    Inventors: Masahiko Higashi, Manabu Nakamura, Kentaro Sera, Hiroyuki Nansei, Yukihiro Utsuno, Hideo Takagi, Tatsuya Kajita
  • Publication number: 20050212035
    Abstract: Tunnel insulating films (3) are formed in element regions demarcated by element isolation insulating films (2). Thereafter, for each memory cell, a floating gate (4) is formed, and an ONO film (5) and a control gate (6) are further formed. Next, a plasma insulating film (7) is formed on surfaces of stacked gates. The plasma insulating film is immune to plane orientation of a base film. Therefore, the entire plasma insulating film (7) has a substantially uniform thickness, and consequently, even if the maximum thickness thereof is not as large as that of a thermal oxide film, hydrogen entrance is prevented when the interlayer insulating film is thereafter formed, and electron leakage is also prevented. The reduction in thickness of this insulating film makes it possible to reduce birds' beaks, and efficiency in erase/write of data can be enhanced.
    Type: Application
    Filed: February 25, 2005
    Publication date: September 29, 2005
    Applicant: FUJITSU AMD SEMICONDUCTOR LIMITED
    Inventors: Yukihiro Utsuno, Manabu Nakamura, Kentaro Sera, Masahiko Higashi, Hiroyuki Nansei, Hideo Takagi, Tatsuya Kajita
  • Publication number: 20050212074
    Abstract: A trench (4) is formed in a semiconductor substrate (1), and then a plasma oxynitride film (5) is formed on a side wall surface and a bottom surface of the trench (4) at a temperature of approximately 300° C. to 650° C. At such a temperature, no outward diffusion of impurities from the semiconductor substrate (1) occurs. Therefore, any problems such as formation of a parasitic transistor hardly occur even when ions of impurities are not implanted thereafter. After the plasma oxynitride film (5) is formed, it is thermally oxidized, and a portion where the outermost surface of the semiconductor substrate (1) meets the wall surface of the trench (4) is turned into a curved surface. As a result, the outermost surface of the semiconductor substrate (1) and the wall surface of the trench (4) meet each other while forming a curved surface, and hence a parasitic transistor is hardly formed at this portion. Consequently, formation of a hump is prevented, thereby achieving favorable characteristics.
    Type: Application
    Filed: February 25, 2005
    Publication date: September 29, 2005
    Applicant: FUJITSU AMD SEMICONDUCTOR LIMITED
    Inventors: Kentaro Sera, Hiroyuki Nansei, Manabu Nakamura, Masahiko Higashi, Yukihiro Utsuno, Hideo Takagi, Tatsuya Kajita
  • Publication number: 20040082198
    Abstract: A chemical oxide film formed on a semiconductor substrate is formed by wet cleaning using a strongly acidic solution so that the adhesion of impurities to the chemical oxide film can be reduced between a wet cleaning process and an insulation film forming process. This makes it possible to prevent insulation degradation of a gate insulation film when the gate insulation film embracing the chemical oxide film is formed in the insulation film forming process in which low-temperature processing is conducted.
    Type: Application
    Filed: September 11, 2003
    Publication date: April 29, 2004
    Inventors: Manabu Nakamura, Hiroyuki Nansei, Kentaro Sera, Masahiko Higashi, Yukihiro Utsuno, Hideo Takagi, Tatsuya Kajita
  • Publication number: 20040043638
    Abstract: After a lower silicon oxide film is formed on a silicon region, a silicon film is formed on the lower silicon oxide film by, for example, a thermal CVD method. Subsequently, the silicon film is completely nitrided by a plasma nitriding method to be replaced by a silicon nitride film. Subsequently, a surface layer of the silicon nitride film is oxidized by a plasma oxidizing method to be replaced by an upper silicon oxide film. An ONO film as a multilayered insulating film composed of the lower silicon oxide film, the silicon nitride film, and the upper silicon oxide film is formed.
    Type: Application
    Filed: August 20, 2003
    Publication date: March 4, 2004
    Applicant: FUJITSU AMD SEMICONDUCTOR LIMITED
    Inventors: Hiroyuki Nansei, Manabu Nakamura, Kentaro Sera, Masahiko Higashi, Yukihiro Utsuno, Hideo Takagi, Tatsuya Kajita