Patents by Inventor Tadato Nagasawa
Tadato Nagasawa 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: 8101504Abstract: A semiconductor chip fabrication method including a modified layer forming step of applying a laser beam having a transmission wavelength to the semiconductor wafer from the back side of the semiconductor wafer along the streets formed on the front side of the semiconductor wafer so that a focal point of the laser beam is set inside the semiconductor wafer, thereby forming a modified layer in the semiconductor wafer along each street, a metal film deposition step of depositing a metal film on the back side of the semiconductor wafer after the modified layer forming step, a semiconductor wafer attaching step of attaching the semiconductor wafer to an adhesive tape supported to an annular frame, and a semiconductor wafer dividing step of applying an external force to the semiconductor wafer in the condition where the semiconductor wafer is attached to the adhesive tape to thereby divide the semiconductor wafer with the metal film into the individual semiconductor chips along the modified layer formed along eachType: GrantFiled: February 18, 2009Date of Patent: January 24, 2012Assignee: Disco CorporationInventor: Tadato Nagasawa
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Publication number: 20090209088Abstract: A semiconductor chip fabrication method including a modified layer forming step of applying a laser beam having a transmission wavelength to the semiconductor wafer from the back side of the semiconductor wafer along the streets formed on the front side of the semiconductor wafer so that a focal point of the laser beam is set inside the semiconductor wafer, thereby forming a modified layer in the semiconductor wafer along each street, a metal film deposition step of depositing a metal film on the back side of the semiconductor wafer after the modified layer forming step, a semiconductor wafer attaching step of attaching the semiconductor wafer to an adhesive tape supported to an annular frame, and a semiconductor wafer dividing step of applying an external force to the semiconductor wafer in the condition where the semiconductor wafer is attached to the adhesive tape to thereby divide the semiconductor wafer with the metal film into the individual semiconductor chips along the modified layer formed along eachType: ApplicationFiled: February 18, 2009Publication date: August 20, 2009Applicant: DISCO CORPORATIONInventor: Tadato Nagasawa
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Patent number: 7549560Abstract: A method of dividing a wafer along a plurality of first dividing lines and a plurality of second dividing lines intersecting with the first dividing lines on the surface of the wafer. The method includes an internal deteriorated layer forming step for forming a deteriorated layer in the inside of the wafer along both the first dividing lines and the second dividing lines by applying a laser beam along the first dividing lines and the second dividing lines. It also includes an intersection deteriorated layer forming step for forming a deteriorated layer thicker than the deteriorated layer formed in the internal deteriorated layer forming step by applying a laser beam to intersection areas between the first and second dividing lines. Thereafter, a dividing step divides the wafer into individual chips along the first and second dividing lines by exertion of external force to the wafer.Type: GrantFiled: May 13, 2005Date of Patent: June 23, 2009Assignee: Disco CorporationInventors: Yusuke Nagai, Toshiyuki Tateishi, Tadato Nagasawa
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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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Patent number: 7439162Abstract: The present invention grinds the rear surface side of a device area to form a recessed portion and an annular reinforcement part on the outer periphery of the recessed portion, removes the annular reinforcement part by grinding or cutting the rear surface of the annular reinforcement part so as to give the wafer a uniform thickness, locates the position of streets in the front surface of the wafer by infrared imaging from the rear surface side of the wafer, and after dividing the wafer into individual devices affixes dicing tape to the rear surface of the wafer divided into devices, supports the rear surface of the wafer on a dicing frame and peels a protective member off the front surface of the wafer, thereby enabling the wafer to be supported using ordinary dicing tape while posing no obstacle to device pick-up after division of the wafer.Type: GrantFiled: November 27, 2006Date of Patent: October 21, 2008Assignee: Disco CorporationInventors: Ryuji Norimoto, Tadato Nagasawa, Takatoshi Masuda
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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
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Publication number: 20070123002Abstract: The present invention grinds the rear surface side of a device area to form a recessed portion and an annular reinforcement part on the outer periphery of the recessed portion, removes the annular reinforcement part by grinding or cutting the rear surface of the annular reinforcement part so as to give the wafer a uniform thickness, locates the position of streets in the front surface of the wafer by infrared imaging from the rear surface side of the wafer, and after dividing the wafer into individual devices affixes dicing tape to the rear surface of the wafer divided into devices, supports the rear surface of the wafer on a dicing frame and peels a protective member off the front surface of the wafer, thereby enabling the wafer to be supported using ordinary dicing tape while posing no obstacle to device pick-up after division of the wafer.Type: ApplicationFiled: November 27, 2006Publication date: May 31, 2007Inventors: Ryuji Norimoto, Tadato Nagasawa, Takatoshi Masuda
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Patent number: 7179724Abstract: A method of processing a wafer having devices in a plurality of areas sectioned by streets arranged in a lattice pattern on the front surface to form a metal film on a back surface thereof, wherein a laser beam application step for applying a laser beam capable of passing through a wafer, along the streets formed on the wafer to form a deteriorated layer is carried out before a metal film forming step for forming a metal film on the back surface of the wafer.Type: GrantFiled: August 10, 2004Date of Patent: February 20, 2007Assignee: Disco CorporationInventors: Tadato Nagasawa, Yusuke Nagai
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Publication number: 20050259459Abstract: A method of dividing a wafer having a plurality of first dividing lines and a plurality of second dividing lines intersecting with the first dividing lines formed on the surface of the wafer along the first dividing lines and the second dividing lines, which comprises an internal deteriorated layer forming step for forming a deteriorated layer in the inside of the water along the first dividing lines and the second dividing lines by applying a laser beam along the first dividing lines and the second dividing lines; an intersection deteriorated layer forming step for forming a deteriorated layer thicker than the deteriorated layer formed in the internal deteriorated layer forming step by applying a laser beam to intersection areas between the first dividing lines and the second dividing lines; and a dividing step for dividing the wafer into individual chips along the first dividing lines and the second dividing lines by exerting external force to the wafer.Type: ApplicationFiled: May 13, 2005Publication date: November 24, 2005Inventors: Yusuke Nagai, Toshiyuki Tateishi, Tadato Nagasawa
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Publication number: 20050037541Abstract: A method of processing a wafer having devices in a plurality of areas sectioned by streets arranged in a lattice pattern on the front surface to form a metal film on a back surface thereof, wherein a laser beam application step for applying a laser beam capable of passing through a wafer, along the streets formed on the wafer to form a deteriorated layer is carried out before a metal film forming step for forming a metal film on the back surface of the wafer.Type: ApplicationFiled: August 10, 2004Publication date: February 17, 2005Inventors: Tadato Nagasawa, Yusuke Nagai