Silver paste

Patent metadata

Field	Value
Publication number	US-12340919-B2
Application number	US-201917417885-A
Country	US
Kind code	B2
Filing date	Nov 28, 2019
Priority date	Dec 26, 2018
Publication date	Jun 24, 2025
Grant date	Jun 24, 2025

Abstract

The present invention provides a silver paste containing at least a silver powder, a binder resin, and an organic solvent, in which a value C BND /S BET is 2.0 to 3.4 where S BET (m 2 /g) represents a specific surface area of the silver powder, and C BND (% by mass) represents a content percentage of the binder resin based on the silver powder, a copper content of the silver powder is 10 to 5000 ppm by mass, and the silver paste has a dry film density of 7.50 g/cm 3 or more. The present invention can provide a silver paste containing a powder in a high concentration and excellent in printability, and accordingly provide a silver conductor film that has a high filling factor and a high film density, exhibits high electrical conductivity, and is excellent in migration resistance.

First claim

The invention claimed is:

1. A silver paste comprising:
a spherical silver powder having an aspect ratio in a range of 1.0 to 1.5;
a binder resin; and
an organic solvent,
wherein a content C AG of the silver powder relative to the silver paste is 92.00 to 97.00% by mass,
wherein a value C BND /S BET is 2.00 to 3.40, where S BET (m 2 /g) represents a specific surface area of the silver powder, and C BND in percent by mass represents a content of the binder resin relative to the silver powder,
wherein a copper content of the silver powder is within a range of 10 to 5000 ppm by mass, and
wherein the silver paste has a dry film density of 7.50 g/cm 3 or more.

2. The silver paste according to claim 1 , wherein the dry film density is 7.60 g/cm 3 or more.

3. The silver paste according to claim 1 or 2 , wherein the value C BND /S BET is 2.50 to 3.10.

4. The silver paste according to claim 1 , wherein the silver powder comprises copper at 30 to 500 ppm by mass.

5. The silver paste according to claim 1 , wherein the content C AG of the silver powder relative to the silver paste is 92.00 to 96.00% by mass.

6. The silver paste according to claim 1 , wherein the specific surface area S BET of the silver powder is 0.10 to 0.30 m 2 /g.

7. The silver paste according to claim 1 , wherein D10 is 1.00 to 3.00 μm and D50 is 3.00 to 7.00 μm, where D10 and D50 respectively represent a 10% value and a 50% value of a volume-based cumulative fraction obtained by laser diffraction particle size distribution measurement of the silver powder.

8. The silver paste according to claim 7 , wherein the D10 is 1.20 to 2.00 μm.

9. The silver paste according to claim 7 or 8 , wherein the D50 is 3.90 to 5.00 μm.

10. The silver paste according to claim 1 , usable for forming a conductor film by a heat treatment at 700° C. or less.

Assignees

• Shoei Chemical Ind Co

Inventors

• Nishimura Kousuke
• Shindo Naoto
• Mashima Hiroshi

Classifications

• B22F1/06

  Metallic powder characterised by the shape of the particles (nanosized particles B22F1/054) · CPC title

• B22F1/00

  Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties · CPC title

• B22F1/102 Primary

  Metallic powder coated with organic material · CPC title

• B22F1/052

  characterised by a mixture of particles of different sizes or by the particle size distribution · CPC title

• B22F1/107

  containing organic material comprising solvents, e.g. for slip casting · CPC title