Patents by Inventor Keiichi Endoh

Keiichi Endoh 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).

  • Patent number: 10903185
    Abstract: A bonding material includes: fine silver particles having an average primary particle diameter of 1 to 50 nm, each of the fine silver particles being coated with an organic compound having a carbon number of not greater than 8, such as hexanoic acid; silver particles having an average primary particle diameter of 0.5 to 4 ?m each of the silver particles being coated with an organic compound, such as oleic acid; a solvent containing a primary alcohol solvent and a terpene alcohol solvent; and a dispersant containing a phosphoric acid ester dispersant (or a phosphoric acid ester dispersant and an acrylic resin dispersant), wherein the content of the fine silver particles is in the range of from 5 wt % to 30 wt %, and the content of the silver particles is in the range of from 60 wt % to 90 wt %, the total content of the fine silver particles and the silver particles being not less than 90 wt %, and wherein the bonding material further includes a sintering aid of a monocarboxylic acid having an ether bond.
    Type: Grant
    Filed: May 15, 2015
    Date of Patent: January 26, 2021
    Assignee: Dowa Electronics Materials Co., Ltd.
    Inventors: Keiichi Endoh, Koichi Yuzaki, Minami Nagaoka, Hiromasa Miyoshi, Satoru Kurita
  • Patent number: 10821558
    Abstract: There is provided an inexpensive bonding material, which can be easily printed on articles to be bonded to each other and which can suppress the generation of voids in the bonded portions of the articles to be bonded to each other, and a bonding method using the same. In a bonding material of a copper paste which contains a copper powder containing 0.3% by weight or less of carbon and having an average particle diameter of 0.1 to 1 ?m, and an alcohol solvent, such as a monoalcohol, a diol, a triol or a terpene alcohol, the content of the copper powder is in the range of from 80% by weight to 95% by weight, and the content of the alcohol solvent is in the range of from 5% by weight to 20% by weight.
    Type: Grant
    Filed: August 31, 2015
    Date of Patent: November 3, 2020
    Assignee: DOWA ELECTRONICS MATERIALS CO., LTD.
    Inventors: Keiichi Endoh, Hiromasa Miyoshi, Kimikazu Motomura, Satoru Kurita
  • Publication number: 20200094318
    Abstract: The present invention aims at providing a bonding material having both preferable dispensing properties and preferable bonding properties, and also providing a bonding method employing the bonding material. Provided are: a bonding material comprising fine silver particles having an average primary particle diameter of smaller than or equal to 130 nm, and a crosslinking-type inter-particle distance keeping agent crosslinking between the fine silver particles and keeping a distance between the fine silver particles; and a bonding method employing the bonding material.
    Type: Application
    Filed: December 28, 2017
    Publication date: March 26, 2020
    Applicant: DOWA ELECTRONICS MATERIALS CO., LTD.
    Inventors: Hideyuki FUJIMOTO, Keiichi ENDOH, Tatsuro HORI, Satoru KURITA
  • Publication number: 20200035637
    Abstract: There are provided a bonding material capable of bonding an electronic part to a substrate by means of a silver bonding layer which is difficult to form large cracks even if the cooling/heating cycle is repeated, and a bonded product wherein an electronic part is bonded to a substrate by using the same. In a bonded product wherein a semiconductor chip such as an SiC chip (having a bonded surface plated with silver) serving as an electronic part is bonded to a copper substrate via a silver bonding layer containing a sintered body of silver, the silver bonding layer has a shear strength of not less than 60 MPa and has a crystalline diameter of not larger than 78 nm on (111) plane thereof.
    Type: Application
    Filed: March 26, 2018
    Publication date: January 30, 2020
    Inventors: Tatsuro Hori, Keiichi Endoh, Hideyuki Fujimoto, Satoru Kurita
  • Patent number: 10543569
    Abstract: A bonding material of a silver paste contains: fine silver particles having an average primary particle diameter of 1 to 200 nm, each of the fine silver particles being coated with an organic compound having a carbon number of not greater than 8, such as sorbic acid; and a solvent mixed with the fine silver particles, wherein a diol, such as an octanediol, is used as the solvent and wherein a triol having a boiling point of 200 to 300° C., a viscosity of 2,000 to 10,000 mPa·s at 20° C. and at least one methyl group, such as 3-methylbutane-1,2,3-triol or 2-methylbutane-1,2,4-triol, is mixed with the solvent as an addition agent.
    Type: Grant
    Filed: May 29, 2015
    Date of Patent: January 28, 2020
    Assignee: Dowa Electronics Materials Co., Ltd.
    Inventors: Satoru Kurita, Takashi Hinotsu, Keiichi Endoh, Hiromasa Miyoshi
  • Publication number: 20190283129
    Abstract: There are provided a bonding material, which is easily printed on a metal substrate, such as a copper substrate, and which can satisfactorily bond an Si chip to the metal substrate by preventing voids from being generated in a metal bonding layer and/or on the boundary between the metal bonding layer and the Si chip or metal copper substrate even if no pre-burning is carried out when the Si chip is bonded to the metal substrate, and a bonding method using the same. In a bonding material of a metal paste containing metal particles, a solvent and a dispersant, the metal particles containing first metal particles (small particles) having an average primary particle diameter of 1 to 40 nm, second metal particles (medium particles) having an average primary particle diameter of 41 to 110 nm, and third metal particles (large particles) having an average primary particle diameter of 120 nm to 10 ?m, the weight percentages of the first, second and third metal particles being 1.
    Type: Application
    Filed: September 27, 2017
    Publication date: September 19, 2019
    Applicant: Dowa Electronics Materials Co., Ltd.
    Inventors: Keiichi Endoh, Minami Kanasugi, Hideyuki Fujimoto, Satoru Kurita
  • Patent number: 10328534
    Abstract: A bonding material of a silver paste includes: fine silver particles having an average primary particle diameter of 1 to 50 nanometers, each of the fine silver particles being coated with an organic compound having a carbon number of not greater than 8, such as hexanoic acid; silver particles having an average primary particle diameter of 0.5 to 4 micrometers, each of the silver particles being coated with an organic compound, such as oleic acid; a solvent containing 3 to 7% by weight of an alcohol and 0.3 to 1% by weight of a triol; a dispersant containing 0.5 to 2% by weight of an acid dispersant and 0.01 to 0.1% by weight of phosphate ester dispersant; and 0.01 to 0.
    Type: Grant
    Filed: June 19, 2014
    Date of Patent: June 25, 2019
    Assignee: Dowa Electronics Materials Co., Ltd.
    Inventors: Keiichi Endoh, Minami Nagaoka, Satoru Kurita, Hiromasa Miyoshi, Yoshiko Kohno, Akihiro Miyazawa
  • Publication number: 20190118257
    Abstract: There are provided a bonding material, which can prevent voids from being generated in a silver bonding layer by preventing the entrainment of bubbles during the formation of a coating film even if the coating film is thickened, and a bonding method using the same. The bonding material of a silver paste includes fine silver particles, a solvent and an addition agent, wherein the solvent contains a first solvent of a diol, such as octanediol, and a second solvent which is a polar solvent (preferably one or more selected from the group consisting of dibutyl diglycol, hexyl diglycol, decanol and dodecanol) having a lower surface tension than that of the first solvent and wherein the addition agent is a triol.
    Type: Application
    Filed: April 25, 2017
    Publication date: April 25, 2019
    Applicant: Dowa Electronics Materials Co., Ltd.
    Inventors: Satoru Kurita, Tatsuro Hori, Keiichi Endoh, Hiromasa Miyoshi
  • Publication number: 20180331063
    Abstract: A method for joining an electronic part, comprising: inserting a joining silver sheet between an electronic part and a substrate, to which the electronic part is to be joined; and heating them to the temperature range of TA (° C.) or higher and TB (° C.) or lower, under application of a pressure to the electronic part and the substrate to make a contact surface pressure of the electronic part and the silver sheet of from 0.5 to 3 MPa. The joining silver sheet comprises silver particles having a particle diameter of from 1 to 250 nm integrated by sintering, and has a capability of further undergoing sintering on heating and retaining the silver sheet at a temperature range of “TA (° C.) or higher and TB (° C.) or lower satisfying the following expression (1): 270?TA<TB?350.
    Type: Application
    Filed: July 23, 2018
    Publication date: November 15, 2018
    Inventors: Satoru KURITA, Keiichi ENDOH, Hiromasa MIYOSHI
  • Patent number: 10090275
    Abstract: A method of bonding two different substances includes the steps of: applying a bonding material containing a flux component that includes an organic material having at least two carboxyl groups to a bonding surface of a bonding object, disposing an object to be bonded on the bonding material, performing preliminary firing at a preset temperature in a state in which the object to be bonded is disposed, and performing a main firing by heating at a temperature higher than the temperature of the preliminary firing.
    Type: Grant
    Filed: December 11, 2015
    Date of Patent: October 2, 2018
    Assignee: DOWA ELECTRONICS MATERIALS CO., LTD.
    Inventors: Keiichi Endoh, Yutaka Hisaeda, Akihiro Miyazawa, Aiko Hirata, Toshihiko Ueyama
  • Patent number: 10008471
    Abstract: A bonded product is obtained by applying a silver paste containing silver nanoparticles having an average primary particle diameter of 1 to 200 nm, and performing firing. A diameter of a crystallite of the bonded product on a (111) plane of Ag when heated at 250° C. for 10 minutes in an inert atmosphere is 65 nm or larger.
    Type: Grant
    Filed: December 11, 2015
    Date of Patent: June 26, 2018
    Assignee: DOWA ELECTRONICS MATERIALS CO., LTD.
    Inventors: Keiichi Endoh, Yutaka Hisaeda, Akihiro Miyazawa, Aiko Hirata, Toshihiko Ueyama
  • Publication number: 20170252874
    Abstract: There is provided an inexpensive bonding material, which can be easily printed on articles to be bonded to each other and which can suppress the generation of voids in the bonded portions of the articles to be bonded to each other, and a bonding method using the same. In a bonding material of a copper paste which contains a copper powder containing 0.3% by weight or less of carbon and having an average particle diameter of 0.1 to 1 ?m, and an alcohol solvent, such as a monoalcohol, a diol, a triol or a terpene alcohol, the content of the copper powder is in the range of from 80% by weight to 95% by weight, and the content of the alcohol solvent is in the range of from 5% by weight to 20% by weight.
    Type: Application
    Filed: August 31, 2015
    Publication date: September 7, 2017
    Inventors: Keiichi Endoh, Hiromasa Miyoshi, Kimikazu Motomura, Satoru Kurita
  • Patent number: 9662748
    Abstract: There is provided a metal nanoparticle dispersion which can be bonded at a lower temperature (for example, 200° C. or less), and enabling to obtain excellent mechanical properties and electric properties of the bonded portion, the metal nanoparticle dispersion, including: metal nanoparticles, with at least a part of a surface of each particle coated with amine A having 8 or more carbon atoms; and a dispersion medium for dispersing the metal nanoparticles, wherein the dispersion medium contains amine B which is primary, secondary, or tertiary amine having 7 or less carbon atoms, and which is linear alkyl amine or alkanol amine.
    Type: Grant
    Filed: April 25, 2014
    Date of Patent: May 30, 2017
    Assignee: DOWA ELECTRONICS MATERIALS CO., LTD.
    Inventors: Keiichi Endoh, Hiromasa Miyoshi, Takashi Hinotsu, Satoru Kurita, Yoshiko Kohno
  • Publication number: 20170120395
    Abstract: A bonding material of a silver paste contains: fine silver particles having an average primary particle diameter of 1 to 200 nm, each of the fine silver particles being coated with an organic compound having a carbon number of not greater than 8, such as sorbic acid; and a solvent mixed with the fine silver particles, wherein a diol, such as an octanediol, is used as the solvent and wherein a triol having a boiling point of 200 to 300° C., a viscosity of 2,000 to 10,000 mPa·s at 20° C. and at least one methyl group, such as 2-methylbutane-2,3,4-triol or 2-methylbutane-1,2,4-triol, is mixed with the solvent as an addition agent.
    Type: Application
    Filed: May 29, 2015
    Publication date: May 4, 2017
    Applicant: Dowa Electronics Materials Co., Ltd.
    Inventors: Satoru Kurita, Takashi Hinotsu, Keiichi Endoh, Hiromasa Miyoshi
  • Publication number: 20170077057
    Abstract: A bonding material includes: fine silver particles having an average primary particle diameter of 1 to 50 nm, each of the fine silver particles being coated with an organic compound having a carbon number of not greater than 8, such as hexanoic acid; silver particles having an average primary particle diameter of 0.5 to 4 ?m each of the silver particles being coated with an organic compound, such as oleic acid; a solvent containing a primary alcohol solvent and a terpene alcohol solvent; and a dispersant containing a phosphoric acid ester dispersant (or a phosphoric acid ester dispersant and an acrylic resin dispersant), wherein the content of the fine silver particles is in the range of from 5 wt % to 30 wt %, and the content of the silver particles is in the range of from 60 wt % to 90 wt %, the total content of the fine silver particles and the silver particles being not less than 90 wt %, and wherein the bonding material further includes a sintering aid of a monocarboxylic acid having an ether bond.
    Type: Application
    Filed: May 15, 2015
    Publication date: March 16, 2017
    Applicant: Dowa Electronics Materials Co., Ltd.
    Inventors: Keiichi Endoh, Koichi Yuzaki, Minami Nagaoka, Hiromasa Miyoshi, Saturo Kurita
  • Patent number: 9533380
    Abstract: The occurrence of uneven drying in the center and end of a surface of a bonding layer during a desolvation process of a pre-drying step is reduced to ensure highly reliable bonding without peeling of a bonding surface even after repeated exposure to heat shock after bonding. The bonding material of the present invention to achieve the object contains silver nanoparticles coated with organic substance having 6 or less carbon atoms and having an average primary particle diameter of 10 to 30 nm as main silver particles, silver nanoparticles coated with an organic substance having 6 or less carbon atoms and having an average primary particle diameter of 100 to 200 nm as secondary silver particles, two kinds of solvents having different boiling points, and a dispersant.
    Type: Grant
    Filed: January 20, 2012
    Date of Patent: January 3, 2017
    Assignee: DOWA ELECTRONICS MATERIALS CO., LTD.
    Inventors: Keiichi Endoh, Satoru Kurita, Minami Nagaoka
  • Patent number: 9486879
    Abstract: There is provided a bonding material capable of forming a bonding body under an inert gas atmosphere such as a nitrogen atmosphere, and capable of exhibiting a bonding strength that endures a practical use even if not a heat treatment is applied thereto at a high temperature, which is the bonding material containing silver nanoparticles coated with a fatty acid having a carbon number of 8 or less and having an average primary particle size of 1 nm or more and 200 nm or less, and silver particles having an average particle size of 0.5 ?m or more and 10 ?m or less, and an organic material having two or more carboxyl groups.
    Type: Grant
    Filed: May 13, 2011
    Date of Patent: November 8, 2016
    Assignee: DOWA ELECTRONICS MATERIALS CO., LTD.
    Inventors: Satoru Kurita, Keiichi Endoh, Yu Saito, Yutaka Hisaeda, Toshihiko Ueyama
  • Publication number: 20160254243
    Abstract: A joining silver sheet with high joining strength contains silver particles having a particle diameter of from 1 to 250 nm integrated by sintering, and has a capability of further undergoing sintering on heating and retaining the silver sheet at a temperature range of from TA to TB (° C.) satisfying 270 £ TA<TB £ 350. A method of making the silver sheet includes subjecting a coated film of a silver paste containing silver powder containing silver particles having a particle diameter of from 1 to 250 nm, and a dispersion medium that undergoes volatilization in a temperature range of 200° C. or lower, which are mixed with each other, to a heat treatment at a temperature range, at which no sintering occurs, and then baking at a temperature of from 170 to 250° C. under application of a pressure of from 5 to 35 MPa.
    Type: Application
    Filed: October 6, 2014
    Publication date: September 1, 2016
    Inventors: Satoru KURITA, Keiichi ENDOH, Hiromasa MIYOSHI
  • Publication number: 20160172328
    Abstract: A method of bonding two different substances includes the steps of: applying a bonding material containing a flux component that includes an organic material having at least two carboxyl groups to a bonding surface of a bonding object, disposing an object to be bonded on the bonding material, performing preliminary firing at a preset temperature in a state in which the object to be bonded is disposed, and performing a main firing by heating at a temperature higher than the temperature of the preliminary firing.
    Type: Application
    Filed: December 11, 2015
    Publication date: June 16, 2016
    Applicant: DOWA Electronics Materials Co., Ltd.
    Inventors: Keiichi ENDOH, Yutaka HISAEDA, Akihiro MIYAZAWA, Aiko NAGAHARA, Toshihiko UEYAMA
  • Publication number: 20160136763
    Abstract: A bonding material of a silver paste includes: fine silver particles having an average primary particle diameter of 1 to 50 nanometers, each of the fine silver particles being coated with an organic compound having a carbon number of not greater than 8, such as hexanoic acid; silver particles having an average primary particle diameter of 0.5 to 4 micrometers, each of the silver particles being coated with an organic compound, such as oleic acid; a solvent containing 3 to 7% by weight of an alcohol and 0.3 to 1% by weight of a triol; a dispersant containing 0.5 to 2% by weight of an acid dispersant and 0.01 to 0.1% by weight of phosphate ester dispersant; and 0.01 to 0.
    Type: Application
    Filed: June 19, 2014
    Publication date: May 19, 2016
    Applicant: DOWA ELECTRONICS MATERIALS CO., LTD.
    Inventors: Keiichi Endoh, Minami Nagaoka, Satoru Kurita, Hiromasa Miyoshi, Yoshiko Kohno, Akihiro Miyazawa