IP Library Granted Patent US 7,618,475
Granted Patent B2
US 7,618,475 · App. 11/340,652 · Granted Nov 17, 2009

Metal powder for electrically conductive paste and electrically conductive paste

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Quick Facts
Patent No.
US 7,618,475
App. No.
11/340,652
Granted
Nov 17, 2009
Kind
B2
Abstract

A metal powder for a conductive paste has an average particle diameter D50 not greater than 5 μm and an X value defined by equation (1) not greater than 0.5: X value= D 50 (μm)/BET specific surface area (m 2 /g)  (1) The metal powder for a conductive paste is particularly preferable when wart-like projections of a diameter not greater than 150 nm are present on the particle surfaces. Typical types of the metal powder include Cu, Ag, Au, Pd, Pt, Ni, Al and alloys thereof. The metal powder for a conductive paste enables fabrication of a conductor having a low void ratio after the paste is fired.

Claims (8)

1. A metal powder for a conductive paste comprising flaky particles whose average particle diameter D 50 is not greater than 5 μm, whose flake aspect ratio of individual particles defined by a particle major axis/thickness is 3 to 30, a proportion of the particles having an aspect ratio of less than 3 or greater than 30 being less than 10%, and whose X value defined by equation (1) below is not greater than 0.5:

X value= D 50 (μm)/BET specific surface area (m 2 /g)  (1.

2. A metal powder for a conductive paste according to claim 1 , wherein wart-like projections of a diameter not greater than 150 nm are present on the particle surfaces.

3. A metal powder for a conductive paste according to claim 1 , wherein the metal powder is Cu powder.

4. A conductive paste using a metal powder set out in claim 1 .

5. A metal powder for a conductive paste according to claim 2 , wherein the metal powder is Cu powder.

6. A conductive paste using a metal powder set out in claim 2 .

7. A conductive paste using a metal powder set out in claim 3 .

Assignments (4)
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Jan 7, 2008
From: DOWA HOLDINGS CO., LTD.
To: DOWA ELECTRONICS MATERIALS CO., LTD.
Reel/Frame 020323/0715 →
CHANGE OF NAME Recorded Nov 5, 2007
From: DOWA MINING CO., LTD.
To: DOWA HOLDINGS CO., LTD.
Reel/Frame 020121/0161 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Oct 2, 2006
From: YAMASHINA, HIROYUKI; FUJITA, HIDEFUMI; IBARAKI, TATSUYA
To: DOWA MINING CO., LTD.
Reel/Frame 018335/0720 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Feb 24, 2006
From: YAMASHINA, HIROYUKI; FUJITA, HIDEFUMI; IBARAKI, TATSUYA
To: DOWA MINING CO., LTD.
Reel/Frame 017216/0622 →