Bonding material and bonding method in which said bonding material is used

Patent metadata

Field	Value
Publication number	US-9533380-B2
Application number	US-201214369504-A
Country	US
Kind code	B2
Filing date	Jan 20, 2012
Priority date	Jan 20, 2012
Publication date	Jan 3, 2017
Grant date	Jan 3, 2017

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.

First claim

The invention claimed is:

1. A bonding material comprising:
silver nanoparticles coated with an 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;
submicron silver particles having an average primary particle diameter of 0.3 to 3.0 μm;
two kinds of solvents having different boiling points, wherein a solvent having a lower boiling point among the two kinds of solvents is at least one solvent selected from butanol, octanol, α-pinene, xylene, and acetylacetone, and a solvent having a higher boiling point among the two kinds of solvents has a boiling point of 230° C. to 320° C. and is at least one solvent selected from alcohol, polyol, and glycol ether; and
a dispersant having a phosphate group,
wherein the content of silver particles including the main silver particles, the secondary silver particles, and the submicron silver particles in the bonding material is 90% by mass or more.

2. The bonding material according to claim 1 , wherein a total amount of the solvents and the dispersant is 5% by mass or less relative to a whole amount of the bonding material.

3. The bonding material according to claim 1 , wherein the organic substance having 6 or less carbon atoms that coats the main silver particles is hexanoic acid.

4. The bonding material according to claim 1 , wherein the main silver particles are contained in an amount of 10 to 40% by mass relative to a whole amount of the bonding material.

5. The bonding material according to claim 1 , wherein a content ratio of a solvent having a lower boiling point to a solvent having a higher boiling point among the two kinds of solvents is 3:5 to 1:1.

6. The bonding material according to claim 1 , wherein
the solvent having a higher boiling point is at least one solvent selected from dodecanol, 2-ethyl-1,3-hexanediol, diethylene glycol monobutyl ether acetate, dibutyl diglycol, hexyl diglycol, 2-ethylhexyl diglycol, and isobornyl cyclohexanol.

7. A bonding method comprising:
a step of applying the bonding material according to claim 1 to surfaces to be bonded of materials to be bonded;
a first heating step of retaining the materials to be bonded under an environment of 80 to 120° C. for 30 to 60 minutes without application of pressure to the surfaces to be bonded; and
a second heating step of retaining the materials to be bonded under an environment of 250° C. for 30 to 60 minutes.

8. The bonding material according to claim 1 , wherein the content of the silver particles in the bonding material is 92% by mass or more.

Assignees

• Endoh Keiichi
• Kurita Satoru
• Nagaoka Minami
• Dowa Electronics Materials Co Ltd

Inventors

• Endoh Keiichi
• Kurita Satoru
• Nagaoka Minami

Classifications

• B23K35/365 Primary

  Selection of non-metallic compositions of coating materials either alone or conjoint with selection of soldering or welding materials · CPC title

• B22F1/0014

  Operations & Transport · mapped topic

• B22F1/0062

  Operations & Transport · mapped topic

• B22F3/1021

  Removal of binder or filler (removal of binder from ceramics C04B35/638) · CPC title

• B23K1/203

  Fluxing, i.e. applying flux onto surfaces · CPC title