Metal-on-ceramic substrates

Patent metadata

Field	Value
Publication number	US-11046051-B2
Application number	US-201615364821-A
Country	US
Kind code	B2
Filing date	Nov 30, 2016
Priority date	Dec 1, 2015
Publication date	Jun 29, 2021
Grant date	Jun 29, 2021

Abstract

A metal-on-ceramic substrate comprises a ceramic layer, a first metal layer, and a bonding layer joining the ceramic layer to the first metal layer. The bonding layer includes thermoplastic polyimide adhesive that contains thermally conductive particles. This permits the substrate to withstand most common die attach operations, reduces residual stress in the substrate, and simplifies manufacturing processes.

First claim

The invention claimed is:

1. A circuit substrate comprising:
a ceramic layer;
a first metal layer; and
a bonding layer joining the first metal layer to the ceramic layer, the bonding layer comprising an adhesive which is thermally conductive; and
a second metal layer on a side of the ceramic layer opposite the first metal layer;
wherein the adhesive of the bonding layer consists of (i) a thermoplastic polyimide, and (ii) thermally conductive particles; and
wherein the thermally conductive particles are selected from the group consisting of silver, copper, gold, diamond, and Si 3 N 4 .

2. The circuit substrate of claim 1 , wherein the bonding layer comprises a foil layer and two adhesive layers on opposite sides of the foil layer.

3. The circuit substrate of claim 1 , wherein the thermally conductive particles are selected from the group consisting of silver, copper, and gold.

4. The circuit substrate of claim 1 , wherein the first metal layer is a metal selected from the group consisting of copper, covetic copper, copper-beryllium, aluminum, aluminum silicon carbide (AlSiC), silver, palladium, platinum, nickel, gold, stainless steel, nickel-cobalt ferrous alloy, and alloys thereof.

5. The circuit substrate of claim 4 , wherein the first metal layer includes a set of sublayers.

6. The circuit substrate of claim 1 , wherein the first metal layer has a thickness of from about 1 mil to about 30 mils.

7. The circuit substrate of claim 1 , wherein the ceramic layer is made of a ceramic selected from the group consisting of aluminum nitride, alumina, BeO, zirconia toughened alumina (ZTA), SiC, and Si 3 N 4 .

8. The circuit substrate of claim 1 , wherein the ceramic layer has a thickness of about 20 mils to about 60 mils.

9. The circuit substrate of claim 1 , wherein the thermally conductive particles are round or flake.

10. A circuit substrate comprising:
a ceramic layer;
a first metal layer; and
a bonding layer joining the first metal layer to the ceramic layer, the bonding layer comprising an adhesive which is thermally conductive; and
a second metal layer on a side of the ceramic layer opposite the first metal layer;
wherein the adhesive of the bonding layer consists of (i) a thermoplastic polyimide, and (ii) thermally conductive particles, and wherein the bonding layer is cured at a temperature from 210° C. to 290° C.

11. The circuit substrate of claim 10 , wherein the bonding layer is thermally stable up to 350° C. in air.

12. The circuit substrate of claim 10 , wherein the bonding layer is cured at a pressure from 65 kPa to 75 kPa, and wherein the bonding layer is cured in air, dry nitrogen, or vacuum.

13. The circuit substrate of claim 10 , wherein the thermally conductive particles are selected from the group consisting of silver, copper, gold, graphene, carbon nanotubes, diamond, boron nitride (BN), aluminum nitride (AlN), and silicon nitride (Si 3 N 4 ).

14. The circuit substrate of claim 10 , wherein the thermally conductive particles are selected from the group consisting of silver, copper, gold, diamond, and Si 3 N 4 .

15. The circuit substrate of claim 10 , wherein the first metal layer is a metal selected from the group consisting of copper, covetic copper, copper-beryllium, aluminum, aluminum silicon carbide (AlSiC), silver, palladium, platinum, nickel, gold, stainless steel, nickel-cobalt ferrous alloy, and alloys thereof.

16. The circuit substrate of claim 10 , wherein the ceramic layer is made of a ceramic selected from the group consisting of aluminum nitride, alumina, BeO, zirconia toughened alumina (ZTA), SiC, and Si 3 N 4 .

17. The circuit substrate of claim 10 , wherein the bonding layer comprises a foil layer and two adhesive layers on opposite sides of the foil layer.

18. The circuit substrate of claim 17 , wherein the foil layer is silver and the first metal layer is a metal selected from the group consisting of copper, covetic copper, copper-beryllium, aluminum, aluminum silicon carbide (AlSiC), palladium, platinum, nickel, gold, stainless steel, nickel-cobalt ferrous alloy, and alloys thereof.

19. The circuit substrate of claim 10 , wherein the bonding layer has a thickness of from about 2 μm to about 150 μm.

20. The circuit substrate of claim 19 , wherein the bonding layer has a thickness of from about 8 μm to about 125 μm.

Assignees

• Materion Corp

Inventors

• Koba Richard J

Classifications

• H10W70/02

  of conductive package substrates serving as an interconnection, e.g. of metal plates (manufacture or treatment of leadframes H10W70/04) · CPC title

• H10W40/255

  having a laminate or multilayered structure, e.g. direct bond copper [DBC] ceramic substrates · CPC title

• C25D5/12

  at least one layer being of nickel or chromium · CPC title

• C04B37/025

  consisting of glass or ceramic material · CPC title

• C04B2237/123

  based on iron group metals, e.g. steel · CPC title