Patents by Inventor Keiichi Kajiyama
Keiichi Kajiyama 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: 8415232Abstract: A wafer is divided into individual devices along division lines formed on the front side of the wafer. The devices are respectively formed in a plurality of regions partitioned by the division lines. A protective member is provided on the front of the wafer, and the back of the wafer is ground to a predetermined thickness. A laser beam is applied to the wafer from the back side of the wafer along the division lines with the focal point of the laser beam set inside the wafer at a position corresponding to each division line, thereby forming a plurality of modified layers inside the wafer along the division lines. The wafer is divided along the modified layers into the individual devices, and the back side of the wafer is ground to remove the modified layers and reduce the thickness of each device to the finished thickness.Type: GrantFiled: October 20, 2011Date of Patent: April 9, 2013Assignee: Disco CorporationInventors: Keiichi Kajiyama, Takatoshi Masuda
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Patent number: 8268656Abstract: An optical device wafer processing method including a protective plate attaching step of attaching a transparent protective plate through a double-sided adhesive tape to the front side of a sapphire substrate constituting an optical device wafer, the double-sided adhesive tape being composed of a sheet capable of blocking ultraviolet radiation and adhesive layers formed on both sides of the sheet, wherein the adhesive force of each adhesive layer can be reduced by applying ultraviolet radiation; a sapphire substrate grinding step of grinding the back side of the sapphire substrate; a modified layer forming step of applying a laser beam to the sapphire substrate from the back side thereof to thereby form a modified layer in the sapphire substrate along each street; a protective plate removing step of removing the protective plate in the condition where the double-sided adhesive tape is left on the sapphire substrate; and a wafer dividing step of breaking the sapphire substrate along each street where the modifType: GrantFiled: April 13, 2010Date of Patent: September 18, 2012Assignee: Disco CorporationInventor: Keiichi Kajiyama
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Publication number: 20120100694Abstract: A wafer is divided into individual devices along division lines formed on the front side of the wafer. The devices are respectively formed in a plurality of regions partitioned by the division lines. A protective member is provided on the front of the wafer, and the back of the wafer is ground to a predetermined thickness. A laser beam is applied to the wafer from the back side of the wafer along the division lines with the focal point of the laser beam set inside the wafer at a position corresponding to each division line, thereby forming a plurality of modified layers inside the wafer along the division lines. The wafer is divided along the modified layers into the individual devices, and the back side of the wafer is ground to remove the modified layers and reduce the thickness of each device to the finished thickness.Type: ApplicationFiled: October 20, 2011Publication date: April 26, 2012Applicant: DISCO CORPORATIONInventors: Keiichi Kajiyama, Takatoshi Masuda
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Patent number: 8025556Abstract: A method of grinding a wafer, including: a wafer holding step for holding a wafer on a conical holding surface of a chuck table having the holding surface; a rough grinding step for performing rough grinding of the wafer held on the holding surface of the chuck table by positioning a grinding surface of a rough grinding wheel at a predetermined inclination angle relative to the holding surface of said chuck table, and rotating the rough grinding wheel; and a finish grinding step for performing finish grinding of the wafer by positioning a grinding surface of a finish grinding wheel in parallel to the holding surface of the chuck table, and rotating the finish grinding wheel in a grinding region of the grinding wheel in a direction toward the vertex of the contact angle between the grinding surface of the finish grinding wheel and the surface to be ground of the wafer.Type: GrantFiled: January 7, 2009Date of Patent: September 27, 2011Assignee: Disco CorporationInventors: Keiichi Kajiyama, Takatoshi Masuda, Shinya Watanabe, Setsuo Yamamoto
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Publication number: 20110097875Abstract: A wafer processing method for dividing a wafer into individual devices along a plurality of crossing streets formed on the front side of the wafer, the individual devices being respectively formed in a plurality of regions partitioned by the streets. The wafer processing method includes the steps of attaching the front side of the wafer to a dicing tape supported to an annular dicing frame, grinding the back side of the wafer to reduce the thickness of the wafer to a predetermined thickness, forming a break start point along each street from the back side of the wafer, applying an external force to the wafer to break the wafer along each street where the break start point is formed, thereby dividing the wafer into the individual devices, attaching the back side of the wafer to a front side of an adhesive tape supported to an annular frame and next removing the adhesive tape from the front side of the adhesive tape, and peeling off and picking up each device from the adhesive tape.Type: ApplicationFiled: October 21, 2010Publication date: April 28, 2011Applicant: DISCO CORPORATIONInventors: Yohei Gokita, Takashi Yamaguchi, Masashi Koyama, Masashi Aoki, Masaaki Suzuki, Katsuhiko Sekiya, Ye Chen, Keiichi Kajiyama, Toshiharu Daii
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Patent number: 7858530Abstract: A processing method for a wafer includes: preparing a wafer which has a device region having plural devices formed on a surface of the wafer; and a peripheral reinforcing portion which is integrally formed around the device region and has a projection projecting outwardly on a rear surface of the wafer. The processing method further includes: removing at least the projection of the peripheral reinforcing portion of the wafer; and transferring the wafer after the removing. In the removing, while the wafer is held on a holding table such that the rear surface of the wafer is exposed and the surface of the wafer closely contacts the holding table, at least the projection of the peripheral reinforcing portion is removed. After the removing of at least the projection, while the wafer is held on the holding table, a holding tape is applied to the rear surface of the wafer and the holding tape is supported by a frame.Type: GrantFiled: March 27, 2007Date of Patent: December 28, 2010Assignee: Disco CorporationInventors: Keiichi Kajiyama, Takatoshi Masuda
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Patent number: 7858496Abstract: Disclosed herein is a wafer processing method for dividing a wafer along a plurality of streets. The wafer processing method includes a back grinding step of grinding the back side of the wafer in an area corresponding to a device area to thereby reduce the thickness of the device area to a predetermined finished thickness and to simultaneously form an annular reinforcing portion on the back side of the wafer in an area corresponding to a peripheral marginal area, a wafer supporting step of attaching the back side of the wafer to a dicing tape, a kerf forming step of cutting the front side of the wafer along each street to thereby form a kerf having a depth corresponding to the thickness of the device area along each street, thereby dividing the device area into individual devices, and a peripheral marginal area removing step of peeling off the peripheral marginal area from the dicing tape.Type: GrantFiled: August 17, 2009Date of Patent: December 28, 2010Assignee: Disco CorporationInventors: Keiichi Kajiyama, Azumi Kondo
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Publication number: 20100267219Abstract: An optical device wafer processing method including a protective plate attaching step of attaching a transparent protective plate through a double-sided adhesive tape to the front side of a sapphire substrate constituting an optical device wafer, the double-sided adhesive tape being composed of a sheet capable of blocking ultraviolet radiation and adhesive layers formed on both sides of the sheet, wherein the adhesive force of each adhesive layer can be reduced by applying ultraviolet radiation; a sapphire substrate grinding step of grinding the back side of the sapphire substrate; a modified layer forming step of applying a laser beam to the sapphire substrate from the back side thereof to thereby form a modified layer in the sapphire substrate along each street; a protective plate removing step of removing the protective plate in the condition where the double-sided adhesive tape is left on the sapphire substrate; and a wafer dividing step of breaking the sapphire substrate along each street where the modifType: ApplicationFiled: April 13, 2010Publication date: October 21, 2010Applicant: DISCO CORPORATIONInventor: Keiichi Kajiyama
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Patent number: 7816264Abstract: A wafer processing method having a step of reducing the thickness of a wafer in only a device forming area where semiconductor chips are formed by grinding and etching the back side of the wafer to thereby form a recess on the back side of the wafer. At the same time, an annular projection is formed around the recess to thereby ensure the rigidity of the wafer. Accordingly, handling in shifting the wafer from the back side recess forming step to a subsequent step of forming a back side rewiring layer can be performed safely and easily.Type: GrantFiled: July 7, 2008Date of Patent: October 19, 2010Assignee: Disco CorporationInventors: Keiichi Kajiyama, Kazuhisa Arai
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Patent number: 7718511Abstract: A processing method for a wafer includes: preparing a wafer which has a device region having plural devices formed on a surface of the wafer; and a peripheral reinforcing portion which is integrally formed around the device region and has a projection projecting outwardly on a rear surface of the wafer. The processing method further includes: holding the wafer on a holding surface of a rotatable holding table such that the rear surface of the wafer is exposed and the surface of the wafer closely contacts the holding table. The processing method further includes: thinning the peripheral reinforcing portion by cutting and removing at least the projection of the peripheral reinforcing portion of the wafer by using a cutting tool having a rotational shaft parallel to the holding surface, while rotating the wafer by rotating the holding table after the holding of the wafer. The peripheral reinforcing portion is thinned so as to have a thickness equal to or thinner than that of the device region by the thinning.Type: GrantFiled: March 27, 2007Date of Patent: May 18, 2010Assignee: Disco CorporationInventors: Keiichi Kajiyama, Takatoshi Masuda
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Patent number: 7677955Abstract: A grinding method for a wafer having a plurality of devices on the front side, wherein the back side of the wafer is ground by a grinding wheel to suppress the motion of heavy metal in the wafer by a gettering effect and also to maintain the die strength of each device at about 1,000 MPa or more. The grinding wheel is composed of a frame and an abrasive member fixed to the free end of the frame. The abrasive member is produced by fixing diamond abrasive grains having a grain size of less than or equal to 1 ?m with a vitrified bond. A protective member is attached to the front side of the wafer and the wafer is held on a chuck table in the condition where the protective member is in contact with the chuck table. The grinding wheel is rotated as rotating the chuck table to thereby grind the back side of the wafer by means of the abrasive member so that the average surface roughness of the back side of the wafer becomes less than or equal to 0.Type: GrantFiled: October 1, 2008Date of Patent: March 16, 2010Assignee: Disco CorporationInventors: Keiichi Kajiyama, Takatoshi Masuda, Shinya Watanabe, Shigehiko Aoki, Hirotoshi Hoshikawa, Yoshikazu Kobayashi, Seiji Harada, Setsuo Yamamoto
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Publication number: 20100055877Abstract: Disclosed herein is a wafer processing method for dividing a wafer along a plurality of streets. The wafer processing method includes a back grinding step of grinding the back side of the wafer in an area corresponding to a device area to thereby reduce the thickness of the device area to a predetermined finished thickness and to simultaneously form an annular reinforcing portion on the back side of the wafer in an area corresponding to a peripheral marginal area, a wafer supporting step of attaching the back side of the wafer to a dicing tape, a kerf forming step of cutting the front side of the wafer along each street to thereby form a kerf having a depth corresponding to the thickness of the device area along each street, thereby dividing the device area into individual devices, and a peripheral marginal area removing step of peeling off the peripheral marginal area from the dicing tape.Type: ApplicationFiled: August 17, 2009Publication date: March 4, 2010Applicant: DISCO CORPORATIONInventors: Keiichi Kajiyama, Azumi Kondo
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Patent number: 7629230Abstract: A wafer processing method for dividing, along streets, a wafer having a device area where devices are formed in a plurality of areas sectioned by the plurality of streets arranged in a lattice pattern on the front surface of a substrate and a peripheral extra area and comprising electrodes which are embedded in the substrate of the device area, comprising a dividing groove forming step for forming dividing grooves having a depth corresponding to the final thickness of each device along the streets; an annular groove forming step for forming an annular groove having a depth corresponding to the final thickness of each device along the boundary between the device area and the peripheral extra area; a protective member affixing step for affixing a protective member to the front surface of the wafer; a rear surface grinding step for grinding a rear surface corresponding to the device area of the substrate of the wafer to expose the dividing grooves and the annular groove to the rear surface of the substrate of thType: GrantFiled: July 16, 2008Date of Patent: December 8, 2009Assignee: Disco CorporationInventors: Kazuma Sekiya, Keiichi Kajiyama
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Patent number: 7625810Abstract: A method of processing a wafer having a device area where a plurality of devices are formed on the front surface and an extra area surrounding the device area and comprising electrodes which are formed in the device area, comprising: a reinforcement forming step for removing an area, which corresponds to the device area, in the back surface of the wafer to reduce the thickness of the device area to a predetermined value and keeping an area, which corresponds to the extra area, in the back surface of the wafer to form an annular reinforcement; and a via-hole forming step for forming a via-hole in the electrodes of the wafer which has been subjected to the reinforcement forming step.Type: GrantFiled: June 21, 2006Date of Patent: December 1, 2009Assignee: Disco CorporationInventors: Keiichi Kajiyama, Koichi Kondo, Yasuomi Kaneuchi
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Publication number: 20090186562Abstract: A method of grinding a wafer, including: a wafer holding step for holding a wafer on a conical holding surface of a chuck table having the holding surface; a rough grinding step for performing rough grinding of the wafer held on the holding surface of the chuck table by positioning a grinding surface of a rough grinding wheel at a predetermined inclination angle relative to the holding surface of said chuck table, and rotating the rough grinding wheel; and a finish grinding step for performing finish grinding of the wafer by positioning a grinding surface of a finish grinding wheel in parallel to the holding surface of the chuck table, and rotating the finish grinding wheel in a grinding region of the grinding wheel in a direction toward the vertex of the contact angle between the grinding surface of the finish grinding wheel and the surface to be ground of the wafer.Type: ApplicationFiled: January 7, 2009Publication date: July 23, 2009Applicant: DISCO CORPORATIONInventors: Keiichi Kajiyama, Takatoshi Masuda, Shinya Watanabe, Setsuo Yamamoto
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Patent number: 7527547Abstract: A method of processing a wafer having a device area in which a plurality of devise are formed and a peripheral excess area surrounding the device area on the front surface, comprising an annular groove forming step for forming an annular groove having a predetermined depth and a predetermined width at the boundary between the device area and the peripheral excess area in the rear surface of the wafer by positioning a cutting blade at the boundary; and a reinforcement forming step for grinding an area corresponding to the device area on the rear surface of the wafer in which the annular groove has been formed, to reduce the thickness of the device area to a predetermined thickness and allowing an area corresponding to the peripheral excess area on the rear surface of the wafer to be left behind to form an annular reinforcement.Type: GrantFiled: May 7, 2007Date of Patent: May 5, 2009Assignee: Disco CorporationInventors: Keiichi Kajiyama, Tadato Nagasawa
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Publication number: 20090098808Abstract: A grinding method for a wafer having a plurality of devices on the front side, wherein the back side of the wafer is ground by a grinding wheel to suppress the motion of heavy metal in the wafer by a gettering effect and also to maintain the die strength of each device at about 1,000 MPa or more. The grinding wheel is composed of a frame and an abrasive member fixed to the free end of the frame. The abrasive member is produced by fixing diamond abrasive grains having a grain size of less than or equal to 1 ?m with a vitrified bond. A protective member is attached to the front side of the wafer and the wafer is held on a chuck table in the condition where the protective member is in contact with the chuck table. The grinding wheel is rotated as rotating the chuck table to thereby grind the back side of the wafer by means of the abrasive member so that the average surface roughness of the back side of the wafer becomes less than or equal to 0.Type: ApplicationFiled: October 1, 2008Publication date: April 16, 2009Applicant: DISCO CORPORATIONInventors: Keiichi Kajiyama, Takatoshi Masuda, Shinya Watanabe, Shigehiko Aoki, Hirotoshi Hoshikawa, Yoshikazu Kobayashi, Seiji Harada, Setsuo Yamamoto
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Publication number: 20090042368Abstract: A wafer processing method for dividing, along streets, a wafer having a device area where devices are formed in a plurality of areas sectioned by the plurality of streets arranged in a lattice pattern on the front surface of a substrate and a peripheral extra area and comprising electrodes which are embedded in the substrate of the device area, comprising a dividing groove forming step for forming dividing grooves having a depth corresponding to the final thickness of each device along the streets; an annular groove forming step for forming an annular groove having a depth corresponding to the final thickness of each device along the boundary between the device area and the peripheral extra area; a protective member affixing step for affixing a protective member to the front surface of the wafer; a rear surface grinding step for grinding a rear surface corresponding to the device area of the substrate of the wafer to expose the dividing grooves and the annular groove to the rear surface of the substrate of thType: ApplicationFiled: July 16, 2008Publication date: February 12, 2009Inventors: Kazuma Sekiya, Keiichi Kajiyama
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Publication number: 20090017623Abstract: A wafer processing method having a step of reducing the thickness of a wafer in only a device forming area where semiconductor chips are formed by grinding and etching the back side of the wafer to thereby form a recess on the back side of the wafer. At the same time, an annular projection is formed around the recess to thereby ensure the rigidity of the wafer. Accordingly, handling in shifting the wafer from the back side recess forming step to a subsequent step of forming a back side rewiring layer can be performed safely and easily.Type: ApplicationFiled: July 7, 2008Publication date: January 15, 2009Applicant: DISCO CORPORATIONInventors: Keiichi Kajiyama, Kazuhisa Arai
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Publication number: 20070264912Abstract: A method of processing a wafer having a device area in which a plurality of devise are formed and a peripheral excess area surrounding the device area on the front surface, comprising an annular groove forming step for forming an annular groove having a predetermined depth and a predetermined width at the boundary between the device area and the peripheral excess area in the rear surface of the wafer by positioning a cutting blade at the boundary; and a reinforcement forming step for grinding an area corresponding to the device area on the rear surface of the wafer in which the annular groove has been formed, to reduce the thickness of the device area to a predetermined thickness and allowing an area corresponding to the peripheral excess area on the rear surface of the wafer to be left behind to form an annular reinforcement.Type: ApplicationFiled: May 7, 2007Publication date: November 15, 2007Inventors: Keiichi Kajiyama, Tadato Nagasawa