Conductive copper paste

• US 5,336,301 A
• Filed: 02/19/1993
• Issued: 08/09/1994
• Est. Priority Date: 02/20/1992
• Status: Expired due to Term

• Current Assignee: Murata Manufacturing Co Limited
• Original Assignee: Murata Manufacturing Co Limited
• Inventors: Tani, Hiroji, Honma, Kanehito
• Primary Examiner(s): KLEMANSKI, HELENE G
• Application Number:
  US08/020,135
• Time in Patent Office: 536 Days
• Field of Search: 106/1.13, 106/1.18, 106/1.26, 252/512, 252/518, 427/123, 427/383.5
• US Class Current: 106/1.18
• CPC Class Codes: H01B 1/22 the conductive material comprising metals or alloys
• CPC Class Codes: H01L 23/49883 the conductive materials containing organic materials or pastes, e.g. for thick films for printed circuits H05K1/092
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H05K 1/092 Dispersed materials, e.g. conductive pastes or inks

Abstract

A conductive copper paste contains copper powder and a glass frit of a zinc borosilicate system as a solid component dispersed in an organic vehicle. The content of said glass frit in the solid component falls in a range of 0.5 to 8 percent by weight. The paste is applied to ceramic green sheets and fired simultaneously with the ceramic green sheets to provide copper coatings on the ceramic sheets.

Claims

1. A conductive copper paste for formation of copper coatings on ceramic substrates, the conductive copper paste consisting essentially of a solid component dispersed in an organic vehicle, the solid component consisting essentially of about 0.5 to 8 percent by weight of a zinc borosilicate glass frit and the remainder of a copper powder, the glass frit consisting essentially of about 40 to 50% by weight of B₂ O₃, about 5 to 20% by weight of SiO₂ and about 30 to 40% by weight of ZnO.

2. The conductive copper paste according to claim 1 in combination with a ceramic substrate wherein the ceramic substrate is made of a BaO.Al₂ O₃.SiO₂ system.

3. The conductive copper paste according to claim 1 wherein the conductive copper paste consists essentially of, by weight, about 73.6 to 79.6% copper powder, about 0.4 to 6.4% glass frit, and the remainder of an organic binder.

4. The conductive copper paste according to claim 1 wherein the copper powder has a particle size of about 0.1 to 5 μ

m.

5. A method of forming a conductive coating on a ceramic substrate, comprising the steps of:

(a) dispersing a copper powder and about 0.5 to 8 percent by weight of a glass frit of a zinc borosilicate system in an organic vehicle to prepare a conductive copper paste;

(b) applying the resultant conductive copper paste on a ceramic substrate made of a BaO.Al₂ O₃.SiO₂ system; and

,

(c) firing the ceramic substrate coated with the conductive copper paste in a non-oxidizing atmosphere.

6. The method according to claim 5 wherein the glass frit consists essentially of about 40 to 50% by weight of B₂ O₃, about 5 to 20% by weight of SiO₂ and about 30 to 40% by weight of ZnO.

11. The method according to claim 5 wherein the glass frit includes about 40 to 50% by weight of B₂ O₃, about 5 to 20% by weight of SiO₂ and about 30 to 40% by weight of ZnO.

7. A conductive copper paste for formation of a copper coating on a ceramic substrate, the conductive copper paste comprising a solid component dispersed in an organic vehicle, the solid component including about 0.5 to 8 percent by weight of a zinc borosilicate glass frit and a copper powder, the glass frit including about 40 to 50% by weight of B₂ O₃, about 5 to 20% by weight of SiO₂ and about 30 to 40% by weight of ZnO.

8. The conductive copper paste according to claim 7 in combination with a ceramic substrate wherein the ceramic substrate is made of a BaO.Al₂ O₃.SiO₂ system.

9. The conductive copper paste according to claim 7 wherein the conductive copper paste includes, by weight, about 73.6 to 79.6% copper powder, about 0.4 to 6.4% glass frit, and an organic binder.

10. The conductive copper paste according to claim 7 wherein the copper powder has a particle size of about 0.1 to 5 μ

m.