Patents by Inventor Makoto Takatoku
Makoto Takatoku 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).
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Patent number: 6693258Abstract: A polycrystalline thin film of good quality is obtained by improving a crystallization process of a semiconductor thin film using laser light. After conducting a film forming step of forming a non-single crystal semiconductor thin film on a surface of a substrate, an annealing step is conducted by irradiating with laser light to convert the non-single crystal semiconductor thin film to a polycrystalline material. The annealing step is conducted by changing and adjusting the cross sectional shape of the laser light to a prescribed region. The semiconductor thin film is irradiated once or more with a pulse of laser light having an emission time width from upstand to downfall of 50 ns or more and having a constant cross sectional area, so as to convert the semiconductor thin film contained in an irradiated region corresponding to the cross sectional area to a polycrystalline material at a time. At this time, the energy intensity of laser light from upstand to downfall is controlled to apply a desired change.Type: GrantFiled: February 4, 2002Date of Patent: February 17, 2004Assignee: Sony CorporationInventors: Yukiyasu Sugano, Masahiro Fujino, Michio Mano, Akihiko Asano, Masumitsu Ino, Takenobu Urazono, Makoto Takatoku
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Patent number: 6653179Abstract: For manufacturing a thin film semiconductor device, first conducted is a film-making step to make a non-single-crystalline semiconductor thin film (4) on an insulating substrate (1). Next conducted is an annealing step to irradiate laser light (50) for once heating and melting the non-single-crystalline semiconductor thin film (4) and then changing it into a polycrystal in its cooling process. Thereafter, a processing step is conducted to form thin film transistors in an integrated form, which includes the polycrystalline semiconductor thin film (4) as their active layer. For the purpose of ensuring uniform crystallization and enlargement of grain sizes, in the annealing step, by using a laser oscillator (51) including an excimer laser source, the laser light (50) having a pulse width not shorter than 50 ns is shaped by an optical system (53) to form a rectangular cross-sectional area whose sides are not shorter than 10 mm to sequentially irradiate the semiconductor thin film (4).Type: GrantFiled: March 29, 2001Date of Patent: November 25, 2003Assignee: Sony CorporationInventors: Masahiro Minegishi, Yasushi Shimogaichi, Makoto Takatoku, Hisao Hayashi
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Publication number: 20030211668Abstract: A thin film transistor has a laminated structure comprising a semiconductor thin film, a gate insulator formed in contact with the surface of the semiconductor thin film, and a gate electrode disposed on the face side of the semiconductor thin film, and is formed on a substrate in a predetermined plan view shape. To fabricate the thin film transistor, first, a first step is carried out in which a semiconductor thin film having a clean surface is formed over the substrate. Next, a second step is carried out in which a protective film PF is formed so as to cover the clean surface of the semiconductor thin film. Further, in a third step, the semiconductor thin film is patterned together with the protective film PF according to the predetermined plan view shape of the thin film transistor. Thereafter, a fourth step is carried out in which the protective film PF is removed from the upper side of the patterned semiconductor thin film to expose a clean surface.Type: ApplicationFiled: June 4, 2003Publication date: November 13, 2003Inventor: Makoto Takatoku
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Publication number: 20030211667Abstract: A thin film transistor has a laminated structure comprising a semiconductor thin film, a gate insulator formed in contact with the surface of the semiconductor thin film, and a gate electrode disposed on the face side of the semiconductor thin film, and is formed on a substrate in a predetermined plan view shape. To fabricate the thin film transistor, first, a first step is carried out in which a semiconductor thin film having a clean surface is formed over the substrate. Next, a second step is carried out in which a protective film PF is formed so as to cover the clean surface of the semiconductor thin film. Further, in a third step, the semiconductor thin film is patterned together with the protective film PF according to the predetermined plan view shape of the thin film transistor. Thereafter, a fourth step is carried out in which the protective film PF is removed from the upper side of the patterned semiconductor thin film to expose a clean surface.Type: ApplicationFiled: June 4, 2003Publication date: November 13, 2003Inventor: Makoto Takatoku
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Patent number: 6632711Abstract: A polycrystalline thin film of good quality is obtained by improving a crystallization process of a semiconductor thin film using laser light. After conducting a film forming step of forming a non-single crystal semiconductor thin film on a surface of a substrate, an annealing step is conducted by irradiating with laser light to convert the non-single crystal semiconductor thin film to a polycrystalline material. The annealing step is conducted by changing and adjusting the cross sectional shape of the laser light to a prescribed region. The semiconductor thin film is irradiated once or more with a pulse of laser light having an emission time width from upstand to downfall of 50 ns or more and having a constant cross sectional area, so as to convert the semiconductor thin film contained in an irradiated region corresponding to the cross sectional area to a polycrystalline material at a time. At this time, the energy intensity of laser light from upstand to downfall is controlled to apply a desired change.Type: GrantFiled: December 8, 2000Date of Patent: October 14, 2003Assignee: Sony CorporationInventors: Yukiyasu Sugano, Masahiro Fujino, Michio Mano, Akihiko Asano, Masumitsu Ino, Takenobu Urazono, Makoto Takatoku
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Publication number: 20030183853Abstract: The state of a polysilicon film formed by excimer laser annealing an amorphous silicon film is to be evaluated. When the amorphous silicon film is annealed to form a polysilicon film, linearity or periodicity presents itself in the spatial structure of the film surface of the polysilicon film formed depending on the energy applied to the amorphous silicon during annealing. This linearity or periodicity is processed as an image and represented numerically from the image by exploiting the linearity or periodicity. The state of the polysilicon film is checked based on the numerical results.Type: ApplicationFiled: March 24, 2003Publication date: October 2, 2003Inventors: Hiroyuki Wada, Yoshimi Hirata, Ayumu Taguchi, Koichi Tatsuki, Nobuhiko Umezu, Shigeo Kubota, Tetsuo Abe, Akifumi Ooshima, Tadashi Hattori, Makoto Takatoku, Yukiyasu Sugano
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Patent number: 6599783Abstract: A thin film transistor has a laminated structure comprising a semiconductor thin film, a gate insulator formed in contact with the surface of the semiconductor thin film, and a gate electrode disposed on the face side of the semiconductor thin film, and is formed on a substrate in a predetermined plan view shape. To fabricate the thin film transistor, first, a first step is carried out in which a semiconductor thin film having a clean surface is formed over the substrate. Next, a second step is carried out in which a protective film PF is formed so as to cover the clean surface of the semiconductor thin film. Further, in a third step, the semiconductor thin film is patterned together with the protective film PF according to the predetermined plan view shape of the thin film transistor. Thereafter, a fourth step is carried out in which the protective film PF is removed from the upper side of the patterned semiconductor thin film to expose a clean surface.Type: GrantFiled: May 24, 2001Date of Patent: July 29, 2003Assignee: Sony CorporationInventor: Makoto Takatoku
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Patent number: 6555423Abstract: In manufacturing a thin-film transistor the condition of a polysilicon film is evaluated, a manufacture margin for the film is determined from the condition evaluated, and the power of an excimer laser annealing apparatus is set based on the manufacture margin. The annealing apparatus anneals an amorphous silicon film, converting the same to a polysilicon film. The surface spatial structure of the polysilicon film thus formed exhibits linearity or periodicity, or both, depending on the energy applied to the amorphous silicon film during the annealing. The image data of the polysilicon film is processed, thereby determining the linearity and/or periodicity in numerical values, by utilizing the auto-correlation function of the surface image of the polysilicon film.Type: GrantFiled: July 25, 2001Date of Patent: April 29, 2003Assignee: Sony CorporationInventors: Hiroyuki Wada, Makoto Takatoku
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Patent number: 6482722Abstract: A process of crystallizing a semiconductor thin film previously formed on a substrate by irradiating the semiconductor thin film with a laser beam, includes: a preparation step of dividing the surface of the substrate into a plurality of division regions, and shaping a laser beam to adjust an irradiation region of the laser beam such that one of the division regions is collectively irradiated with one shot of the laser beam; a crystallization step of irradiating one of the division regions with the laser beam while optically modulating the intensity of the laser beam such that a cyclic light-and-dark pattern is projected on the irradiation region, and irradiating the same division region by at least one time after shifting the pattern such that the light and dark portions of the pattern after shifting are not overlapped to those of the pattern before shifting; and a scanning step of shifting the irradiation region of the laser beam to the next division region, and repeating the crystallization step for theType: GrantFiled: October 3, 2001Date of Patent: November 19, 2002Assignee: Sony CorporationInventors: Masafumi Kunii, Makoto Takatoku, Michio Mano
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Patent number: 6440824Abstract: In crystallizing a semiconductor thin film of large area by overlapping regions of irradiation with a laser beam, uniform crystallinity of the film is achieved. A semiconductor thin film is crystallized by performing shaping laser light emitted to define a laser beam which has a predetermined intensity distribution in a predetermined irradiation region, and repeatedly irradiating the semiconductor thin film with the laser beam while scanning the film so that irradiation regions may be overlapped. The laser beam is shaped so that the sectional intensity distribution of the laser beam in the irradiation region as taken in the direction of the scanning may be convex, and that the peak of the intensity distribution lies at a position which is between the front end and rear end of the irradiation region in relation to the scanning direction and which is nearer to the front end with respect to the middle of the irradiation region.Type: GrantFiled: July 27, 2000Date of Patent: August 27, 2002Assignee: Sony CorporationInventors: Hisao Hayashi, Hiroyuki Ikeda, Makoto Takatoku
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Publication number: 20020110962Abstract: In this invention, the condition of a polysilicon film is evaluated, and a manufacture margin for the film is determined from the condition evaluated. The power of an excimer laser annealing apparatus is set based on the manufacture margin. The annealing apparatus anneals an amorphous silicon film, converting the same to a polysilicon film. The surface spatial structure of the polysilicon film thus formed exhibits linearity or periodicity, or both, depending on the energy applied to the amorphous silicon film during the annealing. The image data of the polysilicon film is processed, thereby determining the linearity and/or periodicity in numerical values, by utilizing the auto-correlation function of the surface image of the polysilicon film. A difference between the auto-correlation function of the surface image of parts of the polysilicon film, which are a source region and a drain region, and the auto-correlation function of the part of the polysilicon film, which lies above a gate electrode, is obtained.Type: ApplicationFiled: July 25, 2001Publication date: August 15, 2002Inventors: Hiroyuki Wada, Makoto Takatoku
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Publication number: 20020096680Abstract: A polycrystalline thin film of good quality is obtained by improving a crystallization process of a semiconductor thin film using laser light. After conducting a film forming step of forming a non-single crystal semiconductor thin film on a surface of a substrate, an annealing step is conducted by irradiating with laser light to convert the non-single crystal semiconductor thin film to a polycrystalline material. The annealing step is conducted by changing and adjusting the cross sectional shape of the laser light to a prescribed region. The semiconductor thin film is irradiated once or more with a pulse of laser light having an emission time width from upstand to downfall of 50 ns or more and having a constant cross sectional area, so as to convert the semiconductor thin film contained in an irradiated region corresponding to the cross sectional area to a polycrystalline material at a time. At this time, the energy intensity of laser light from upstand to downfall is controlled to apply a desired change.Type: ApplicationFiled: February 4, 2002Publication date: July 25, 2002Inventors: Yukiyasu Sugano, Masahiro Fujino, Michio Mano, Akihiko Asano, Masumitsu Ino, Takenobu Urazono, Makoto Takatoku
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Publication number: 20020066902Abstract: A thin film transistor has a laminated structure comprising a semiconductor thin film, a gate insulator formed in contact with the surface of the semiconductor thin film, and a gate electrode disposed on the face side of the semiconductor thin film, and is formed on a substrate in a predetermined plan view shape. To fabricate the thin film transistor, first, a first step is carried out in which a semiconductor thin film having a clean surface is formed over the substrate. Next, a second step is carried out in which a protective film PF is formed so as to cover the clean surface of the semiconductor thin film. Further, in a third step, the semiconductor thin film is patterned together with the protective film PF according to the predetermined plan view shape of the thin film transistor. Thereafter, a fourth step is carried out in which the protective film PF is removed from the upper side of the patterned semiconductor thin film to expose a clean surface.Type: ApplicationFiled: May 24, 2001Publication date: June 6, 2002Inventor: Makoto Takatoku
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Patent number: 6388386Abstract: A process of crystallizing a semiconductor thin film previously formed on a substrate by irradiating the semiconductor thin film with a laser beam, includes: a preparation step of dividing the surface of the substrate into a plurality of division regions, and shaping a laser beam to adjust an irradiation region of the laser beam such that one of the division regions is collectively irradiated with one shot of the laser beam; a crystallization step of irradiating one of the division regions with the laser beam while optically modulating the intensity of the laser beam such that a cyclic light-and-dark pattern is projected on the irradiation region, and irradiating the same division region by at least one time after shifting the pattern such that the light and dark portions of the pattern after shifting are not overlapped to those of the pattern before shifting; and a scanning step of shifting the irradiation region of the laser beam to the next division region, and repeating the crystallization step for theType: GrantFiled: April 14, 2000Date of Patent: May 14, 2002Assignee: Sony CorporationInventors: Masafumi Kunii, Makoto Takatoku, Michio Mano
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Publication number: 20020047580Abstract: A process of crystallizing a semiconductor thin film previously formed on a substrate by irradiating the semiconductor thin film with a laser beam, includes:Type: ApplicationFiled: October 3, 2001Publication date: April 25, 2002Inventors: Masafumi Kunii, Makoto Takatoku, Michio Mano
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Publication number: 20020047579Abstract: A process of crystallizing a semiconductor thin film previously formed on a substrate by irradiating the semiconductor thin film with a laser beam, includes:Type: ApplicationFiled: October 3, 2001Publication date: April 25, 2002Inventors: Masafumi Kunii, Makoto Takatoku, Michio Mano
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Publication number: 20010038105Abstract: The state of a polysilicon film formed by excimer laser annealing an amorphous silicon film is to be evaluated. When the amorphous silicon film is annealed to form a polysilicon film, linearity or periodicity presents itself in the spatial structure of the film surface of the polysilicon film formed depending on the energy applied to the amorphous silicon during annealing. This linearity or periodicity is processed as an image and represented numerically from the image by exploiting the linearity or periodicity. The state of the polysilicon film is checked based on the numerical results.Type: ApplicationFiled: January 8, 2001Publication date: November 8, 2001Inventors: Hiroyuki Wada, Yoshimi Hirata, Ayumu Taguchi, Koichi Tatsuki, Nobuhiko Umezu, Shigeo Kubota, Tetsuo Abe, Akifumi Ooshima, Tadashi Hattori, Makoto Takatoku, Yukiyasu Sugano
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Publication number: 20010011726Abstract: A thin film semiconductor device formed as integrated circuits on an insulating substrate with bottom gate type thin film transistors stacked with gate electrodes, a gate insulating film and a semiconductor thin film in the order from below upward. The gate electrodes comprise metallic materials with thickness less than 100 nm. The gate insulating film has a thickness thicker than the gate electrodes. The semiconductor thin film comprises polycrystalline silicon crystallized by a laser beam. By reducing thickness of metallic gate electrodes, thermal capacity becomes small and difference in thermal condition on the metallic gate electrodes and on the insulating substrate made of glass or the like becomes small. This invention relates to the task of uiforming and optimizing recrystallization by a laser anneal treatment provided for the semiconductor thin film which works as an active layer of the bottom gate type thin film transistors.Type: ApplicationFiled: January 31, 2001Publication date: August 9, 2001Applicant: Sony CorporationInventors: Hisao Hayashi, Masahiro Fujino, Yasushi Shimogaichi, Makoto Takatoku
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Publication number: 20010000243Abstract: A polycrystalline thin film of good quality is obtained by improving a crystallization process of a semiconductor thin film using laser light. After conducting a film forming step of forming a non-single crystal semiconductor thin film on a surface of a substrate, an annealing step is conducted by irradiating with laser light to convert the non-single crystal semiconductor thin film to a polycrystalline material. The annealing step is conducted by changing and adjusting the cross sectional shape of the laser light to a prescribed region. The semiconductor thin film is irradiated once or more with a pulse of laser light having an emission time width from upstand to downfall of 50 ns or more and having a constant cross sectional area, so as to convert the semiconductor thin film contained in an irradiated region corresponding to the cross sectional area to a polycrystalline material at a time. At this time, the energy intensity of laser light from upstand to downfall is controlled to apply a desired change.Type: ApplicationFiled: December 8, 2000Publication date: April 12, 2001Inventors: Yukiyasu Sugano, Masahiro Fujino, Michio Mano, Akihiko Asano, Masumitsu Ino, Takenobu Urazono, Makoto Takatoku
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Patent number: 5708485Abstract: To give an electric shield function and an electric contact function to a light shielding film formed on a drive substrate.An active matrix display device includes a drive substrate 1 having pixels 4, an opposed substrate 2 having an opposed electrode 5, and a liquid crystal 3 held in a space defined between the drive substrate 1 and the opposed substrate 2. An upper layer portion of the drive substrate 1 includes pixel electrodes 6 formed individually for the pixels 4. A lower layer portion of the drive substrate 1 includes thin-film transistors 7 for individually driving the pixel electrodes 6, scanning lines 8, and signal lines 9. A light shielding film having conductivity is interposed between the upper layer portion and the lower layer portion, and is divided into mask shielding films 16M and pad shielding films 16P. Each mask shielding film 16M is continuously patterned along each row of the pixels 4 to partially shield at least the corresponding thin-film transistor 7.Type: GrantFiled: March 18, 1996Date of Patent: January 13, 1998Assignee: Sony CorporationInventors: Takusei Sato, Yoshihiro Hashimoto, Kazuyoshi Yoshida, Shingo Makimura, Makoto Takatoku