Patents by Inventor Tomomichi Takatsu
Tomomichi Takatsu 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: 9422462Abstract: An adhesive sheet of the invention includes a substrate and an adhesive composition laminated thereon, the substrate including polyvinyl chloride and a polyester-based plasticizer, wherein the adhesive composition includes two different (meth)acrylate copolymer components (A) and (B) in a mass ratio ranging from 10:90 to 90:10, wherein a content of a cross-linking agent which reacts with functional groups of the component (A) and the component (B) is in a range of 0.5 to 20 mass parts with respect to 100 mass parts of a sum of the component (A) and the component (B), and wherein 10 to 95 mass % of the monomer unit composing the component (A) is 2-ethylhexyl acrylate, and 10 to 95 mass % of the monomer unit composing the component (B) is butyl acrylate.Type: GrantFiled: May 28, 2012Date of Patent: August 23, 2016Assignee: DENKA COMPANY LIMITEDInventors: Takeshi Saito, Tomomichi Takatsu
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Patent number: 9267059Abstract: After an adhesive sheet is pasted on a semiconductor wafer, an adhesive of the sheet increases tight attachment to the semiconductor wafer because wetting spreads over time. Due to this, at the time of peeling the adhesive sheet from the ground semiconductor wafer, the semiconductor wafer used to be damaged. This phenomenon is likely to occur for a thinner semiconductor wafer. The present invention resides in an adhesive sheet including a substrate and an adhesive layer disposed on the substrate. The substrate is formed of an ethylene/vinyl acetate copolymer having a vinyl acetate content of 10% by mass or less. The adhesive layer contains 100 parts by mass of a (meth)acrylate ester copolymer, 1 to 10 parts by mass of a cross-linker, 0.05 to 5 parts by mass of a silicone compound. The (meth)acrylate ester copolymer is formed of a copolymer produced by polymerizing a (meth)acrylate ester monomer and a functional-group-containing monomer.Type: GrantFiled: May 31, 2010Date of Patent: February 23, 2016Assignee: DENKA COMPANY LIMITEDInventors: Masashi Kume, Tomomichi Takatsu
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Patent number: 8975347Abstract: Provided is a method for manufacturing electronic component improved in chip-holding efficiency, pickup efficiency and contamination resistance in a well-balanced manner, the method comprising a semi-cured adhesive layer-forming step of forming a semi-cured adhesive layer on the rear face of a wafer, a fixing step of fixing the semi-cured adhesive layer of the wafer on a ring frame with a cohesive sheet, a dicing step of dicing the wafer into semiconductor chips, a UV-irradiating step of irradiating ultraviolet ray, and a pick-up step of picking up the chips and semi-cured adhesive layers from the cohesive layer, wherein the cohesive sheet has a cohesive layer of a cohesive agent having a particular composition formed on one face of its base film.Type: GrantFiled: September 14, 2011Date of Patent: March 10, 2015Assignee: Denki Kagaku Kogyo Kabushiki KaishaInventors: Takeshi Saito, Tomomichi Takatsu
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Patent number: 8764933Abstract: Provided is a adhesive and an adhesive sheet which exhibit excellent chip-holding properties during dicing and from which chips can be easily stripped during pick up, even when considering changes over time. It is a adhesive composition which contains both (A) a (meth)acrylic acid ester copolymer component that has functional-group containing monomer units and a weight average molecular weight of less than 350,000 and (B) a (meth)acrylic ester copolymer component that has functional-group containing monomer units and a weight average molecular weight of 350,000 to 2,000,000 at a weight ratio of 10:90 to 90:10, and further contains 0.5 to 20 parts by mass of a crosslinking agent per 100 parts by mass of components (A) and (B) in total, the crosslinking agent being a crosslinking agent that reacts with both the functional groups of the component (A) and the functional groups of the component (B).Type: GrantFiled: February 9, 2010Date of Patent: July 1, 2014Assignee: Denki Kagaku Kogyo Kabushiki KaishaInventors: Tomomichi Takatsu, Masashi Kume
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Publication number: 20140134431Abstract: An adhesive sheet of the invention includes a substrate and an adhesive composition laminated thereon, the substrate including polyvinyl chloride and a polyester-based plasticizer, wherein the adhesive composition includes two different (meth)acrylate copolymer components (A) and (B) in a mass ratio ranging from 10:90 to 90:10, wherein a content of a cross-linking agent which reacts with functional groups of the component (A) and the component (B) is in a range of 0.5 to 20 mass parts with respect to 100 mass parts of a sum of the component (A) and the component (B), and wherein 10 to 95 mass % of the monomer unit composing the component (A) is 2-ethylhexyl acrylate, and 10 to 95 mass % of the monomer unit composing the component (B) is butyl acrylate.Type: ApplicationFiled: May 28, 2012Publication date: May 15, 2014Applicant: Denki Kagaku Kogyo Kabushiki KaishaInventors: Takeshi Saito, Tomomichi Takatsu
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Patent number: 8652942Abstract: A method for manufacturing electronic parts, which is characteristic in that it permits reduction of contamination to the semi-cured adhesive layer formed on semiconductor wafer and the cohesive sheet used therein is superior in adhesiveness for example to the lead frame, the method comprising a semi-cured adhesive layer-forming step of forming a semi-cured adhesive layer by coating a pasty adhesive entirely over the rear face of a wafer and curing the pasty adhesive partially by radiation-ray irradiation or heating into the sheet shape, a fixing step of fixing the semi-cured adhesive layer formed on a wafer and a ring frame by bonding them to the cohesive layer of a cohesive sheet, a dicing step of dicing the wafer together with the semi-cured adhesive layer with a dicing blade into semiconductor chips, and a pick-up step of picking up the chips carrying the semi-cured adhesive layer from the cohesive layer of the cohesive sheet after radiation-ray irradiation, wherein the photopolymerization initiator in thType: GrantFiled: September 14, 2011Date of Patent: February 18, 2014Assignee: Denki Kagaku Kogyo Kabushiki KaishaInventors: Takeshi Saito, Tomomichi Takatsu
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Publication number: 20130183812Abstract: A method for manufacturing electronic parts, which is characteristic in that it permits reduction of contamination to the semi-cured adhesive layer formed on semiconductor wafer and the cohesive sheet used therein is superior in adhesiveness for example to the lead frame, the method comprising a semi-cured adhesive layer-forming step of forming a semi-cured adhesive layer by coating a pasty adhesive entirely over the rear face of a wafer and curing the pasty adhesive partially by radiation-ray irradiation or heating into the sheet shape, a fixing step of fixing the semi-cured adhesive layer formed on a wafer and a ring frame by bonding them to the cohesive layer of a cohesive sheet, a dicing step of dicing the wafer together with the semi-cured adhesive layer with a dicing blade into semiconductor chips, and a pick-up step of picking up the chips carrying the semi-cured adhesive layer from the cohesive layer of the cohesive sheet after radiation-ray irradiation, wherein the photopolymerization initiator in thType: ApplicationFiled: September 14, 2011Publication date: July 18, 2013Applicant: DENKI KAGAKU KOGYO KABUSHIKI KAISHAInventors: Takeshi Saito, Tomomichi Takatsu
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Publication number: 20130171804Abstract: Provided is a method for manufacturing electronic component improved in chip-holding efficiency, pickup efficiency and contamination resistance in a well-balanced manner, the method comprising a semi-cured adhesive layer-forming step of forming a semi-cured adhesive layer on the rear face of a wafer, a fixing step of fixing the semi-cured adhesive layer of the wafer on a ring frame with a cohesive sheet, a dicing step of dicing the wafer into semiconductor chips, a UV-irradiating step of irradiating ultraviolet ray, and a pick-up step of picking up the chips and semi-cured adhesive layers from the cohesive layer, wherein the cohesive sheet has a cohesive layer of a cohesive agent having a particular composition formed on one face of its base film.Type: ApplicationFiled: September 14, 2011Publication date: July 4, 2013Applicant: DENKI KAGAKU KOGYO KABUSHIKI KAISHAInventors: Takeshi Saito, Tomomichi Takatsu
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Patent number: 8399338Abstract: The objective is to limit pickup defects when chips with a semi-cured adhesive layer are picked up following dicing by lowering the adhesive strength of an ultraviolet curable adhesive beforehand while improving the cohesive force. Provided is a dicing method for semiconductor wafers with a semi-cured adhesive layer that comprises a process to coat the back surface of semiconductor wafers with a paste-like adhesive and semi-cure the paste-like adhesive in a sheet form using heating or ultraviolet irradiation to form a semi-cured adhesive layer, a gluing process to glue an adhesive sheet, wherein an ultraviolet curable adhesive is laminated on a base film, onto the semi-cured adhesive layer, an ultraviolet irradiation process to apply ultraviolet irradiation to the ultraviolet curable adhesive, and a dicing process to dice the semi-cured adhesive layer glued to the adhesive sheet and the semiconductor wafers.Type: GrantFiled: November 11, 2009Date of Patent: March 19, 2013Assignee: Denki Kagaku Kogyo Kabushiki KaishaInventors: Takeshi Saito, Tomomichi Takatsu
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Patent number: 8389629Abstract: A multi-layered adhesive sheet 100, includes: a substrate film 106, an adhesive layer 103 formed by coating an adhesive having a specific composition onto this substrate film 106, and a die attachment film 105 laminated on the adhesive layer 103. The multi-layered adhesive sheet 100 employing an adhesive having this specific composition has superior retention of die chip 108 during the dicing of silicon wafer 101, allows the die attachment film 105 and adhesive layer 103 to be easily peeled apart during a pick-up operation of the die chip 108, and prevents poor adhesion during the bonding of die chip 108 to lead frame 111.Type: GrantFiled: October 16, 2007Date of Patent: March 5, 2013Assignee: Denki Kagaku Kogyo Kabushiki KaishaInventors: Takeshi Saito, Tomomichi Takatsu
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Publication number: 20120258572Abstract: Disclosed is an adhesive sheet that has a base film and an ultraviolet curable adhesive layered upon the base film. The ultraviolet curable adhesive includes 100 parts by mass of an acrylic ester copolymer with a weight-average molecular weight of at least one million, 20 to 200 parts by mass of a photopolymerizable acrylate having at least three carbon-carbon double bonds, and 0.1 to 10 parts by mass of an isocyanate curing agent. From among the monomers used during the copolymerization of the acrylic ester copolymer, a monomer having one or both of a hydroxyl group and a carboxyl group is included at no more than 0.1 mass %.Type: ApplicationFiled: October 29, 2010Publication date: October 11, 2012Applicant: DENKI KAGAKU KOGYO KABUSHIKI KAISHAInventor: Tomomichi Takatsu
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Publication number: 20120231266Abstract: Provided are an adhesive sheet having a conductive die attach film that is superior in semiconductor chip-holding efficiency and pick-up efficiency and an electronic component prepared by using the adhesive sheet. An adhesive sheet, including a base film, an adhesive layer laminated on one face of the base film and a die attach film containing a conductive filler laminated on the adhesive layer, wherein the adhesive layer is shaped from a bonding composition containing a multifunctional isocyanate curing agent: 0.5 to 20 parts by mass with respect to a (meth)acrylic ester copolymer having a carboxyl group-containing monomer's copolymerization rate of less than 0.5%:100 parts by mass.Type: ApplicationFiled: November 16, 2010Publication date: September 13, 2012Applicant: DENKI KAGAKU KOGYO KABUSHIKI KAISHAInventors: Takeshi Saitoh, Tomomichi Takatsu
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Patent number: 8236416Abstract: An adhesive sheet and a method for producing electronic components using the sheet are provided. An adhesive sheet comprising a substrate layer; an antistatic layer formed on one surface of the substrate layer and containing an organic binder, an antistatic agent, an antifriction agent and a curing agent; and an adhesive layer formed on the other surface of the substrate layer; and a method for producing electronic components using the adhesive sheet.Type: GrantFiled: November 29, 2006Date of Patent: August 7, 2012Assignee: Denki Kagaku Kogyo Kabushiki KaishaInventors: Satoru Kawata, Tomomichi Takatsu
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Publication number: 20120052772Abstract: After an adhesive sheet is pasted on a semiconductor wafer, an adhesive of the sheet increases tight attachment to the semiconductor wafer because wetting spreads over time. Due to this, at the time of peeling the adhesive sheet from the ground semiconductor wafer, the semiconductor wafer used to be damaged. This phenomenon is likely to occur for a thinner semiconductor wafer. The present invention resides in an adhesive sheet including a substrate and an adhesive layer disposed on the substrate. The substrate is formed of an ethylene/vinyl acetate copolymer having a vinyl acetate content of 10% by mass or less. The adhesive layer contains 100 parts by mass of a (meth)acrylate ester copolymer, 1 to 10 parts by mass of a cross-linker, 0.05 to 5 parts by mass of a silicone compound. The (meth)acrylate ester copolymer is formed of a copolymer produced by polymerizing a (meth)acrylate ester monomer and a functional-group-containing monomer.Type: ApplicationFiled: May 31, 2010Publication date: March 1, 2012Inventors: Masashi Kume, Tomomichi Takatsu
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Patent number: 8114759Abstract: With the invented dicing method, by increasing the cohesive strength while decreasing the adhesive strength of an ultraviolet-curing adhesive in advance, mixing of the ultraviolet-curing adhesive layer of an adhesive sheet with a die attach film on a dicing line can be decreased and pickup failures can be reduced, when picking up chips having a die attach film after dicing. The dicing method for a semiconductor wafer with a die-attach film comprises a first gluing step in which a die attach film is affixed to an adhesive sheet having an ultraviolet-curing adhesive laminated on a base material film, a second gluing step in which a semiconductor wafer is affixed to the opposite side of the die attach film affixed to the adhesive sheet, an ultraviolet irradiation step in which the ultraviolet-curing adhesive is irradiated with ultraviolet light, and a dicing step in which the semiconductor wafer and the die attach film affixed to the adhesive sheet are diced.Type: GrantFiled: March 3, 2009Date of Patent: February 14, 2012Assignee: Denki Kagaku Kogyo Kabushiki KaishaInventors: Takeshi Saito, Tomomichi Takatsu
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Publication number: 20120000599Abstract: Provided is a adhesive and an adhesive sheet which exhibit excellent chip-holding properties during dicing and from which chips can be easily stripped during pick up, even when considering changes over time. It is a adhesive composition which contains both (A) a (meth)acrylic acid ester copolymer component that has functional-group containing monomer units and a weight average molecular weight of less than 350,000 and (B) a (meth)acrylic ester copolymer component that has functional-group containing monomer units and a weight average molecular weight of 350,000 to 2,000,000 at a weight ratio of 10:90 to 90:10, and further contains 0.5 to 20 parts by mass of a crosslinking agent per 100 parts by mass of components (A) and (B) in total, the crosslinking agent being a crosslinking agent that reacts with both the functional groups of the component (A) and the functional groups of the component (B).Type: ApplicationFiled: February 9, 2010Publication date: January 5, 2012Applicant: DENKI KAGAKU KOGYO KABUSHIKI KAISHAInventors: Tomomichi Takatsu, Masashi Kume
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Publication number: 20110223743Abstract: The objective is to limit pickup defects when chips with a semi-cured adhesive layer are picked up following dicing by lowering the adhesive strength of an ultraviolet curable adhesive beforehand while improving the cohesive force. Provided is a dicing method for semiconductor wafers with a semi-cured adhesive layer that comprises a process to coat the back surface of semiconductor wafers with a paste-like adhesive and semi-cure the paste-like adhesive in a sheet form using heating or ultraviolet irradiation to form a semi-cured adhesive layer, a gluing process to glue an adhesive sheet, wherein an ultraviolet curable adhesive is laminated on a base film, onto the semi-cured adhesive layer, an ultraviolet irradiation process to apply ultraviolet irradiation to the ultraviolet curable adhesive, and a dicing process to dice the semi-cured adhesive layer glued to the adhesive sheet and the semiconductor wafers.Type: ApplicationFiled: November 11, 2009Publication date: September 15, 2011Applicant: DENKI KAGAKU KOGYO KABUSHIKI KAISHAInventors: Takeshi Saito, Tomomichi Takatsu
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Publication number: 20110065261Abstract: With the invented dicing method, by increasing the cohesive strength while decreasing the adhesive strength of an ultraviolet-curing adhesive in advance, mixing of the ultraviolet-curing adhesive layer of an adhesive sheet with a die attach film on a dicing line can be decreased and pickup failures can be reduced, when picking up chips having a die attach film after dicing. The dicing method for a semiconductor wafer with a die-attach film comprises a first gluing step in which a die attach film is affixed to an adhesive sheet having an ultraviolet-curing adhesive laminated on a base material film, a second gluing step in which a semiconductor wafer is affixed to the opposite side of the die attach film affixed to the adhesive sheet, an ultraviolet irradiation step in which the ultraviolet-curing adhesive is irradiated with ultraviolet light, and a dicing step in which the semiconductor wafer and the die attach film affixed to the adhesive sheet are diced.Type: ApplicationFiled: March 3, 2009Publication date: March 17, 2011Inventors: Takeshi Saito, Tomomichi Takatsu
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Publication number: 20100248452Abstract: A multi-layered adhesive sheet 100, includes: a substrate film 106, an adhesive layer 103 formed by coating an adhesive having a specific composition onto this substrate film 106, and a die attachment film 105 laminated on the adhesive layer 103. The multi-layered adhesive sheet 100 employing an adhesive having this specific composition has superior retention of die chip 108 during the dicing of silicon wafer 101, allows the die attachment film 105 and adhesive layer 103 to be easily peeled apart during a pick-up operation of the die chip 108, and prevents poor adhesion during the bonding of die chip 108 to lead frame 111.Type: ApplicationFiled: October 16, 2007Publication date: September 30, 2010Applicant: DENKI KAGAKU KOGYO KABUSHIKI KAISHAInventors: Takeshi Saito, Tomomichi Takatsu
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ADHESIVE, ADHESIVE SHEET, MULTI-LAYERED ADHESIVE SHEET, AND PRODUCTION METHOD FOR AN ELECTRONIC PART
Publication number: 20100240196Abstract: A multi-layered adhesive sheet includes a substrate film, an adhesive layer formed by coating an adhesive having a specific composition onto the substrate film, and a die attachment film laminated on the adhesive layer. The multi-layered adhesive sheet employing an adhesive having this specific composition is superior in retention of a die chip during dicing of a silicon wafer, the multi-layered adhesive sheet is less likely to come off a ring frame during the dicing of the silicon wafer, and it allows for the die attachment film and the adhesive layer to be easily peeled apart during a pick-up operation of a die chip.Type: ApplicationFiled: October 16, 2007Publication date: September 23, 2010Inventors: Takeshi Saito, Tomomichi Takatsu