Copper-ceramic composite
The invention relates to a copper-ceramic composite comprising: a ceramic substrate; and a copper or copper alloy coating on the ceramic substrate, the copper or copper alloy having grain sizes of 10 μm to 300 μm.
1. A copper-ceramic composite comprising:
a ceramic substrate,
a coating which is present on the ceramic substrate and is composed of copper or a copper alloy,
wherein the copper or the copper alloy has
grain sizes in the range from 10 μm to 300 μm;
a grain size number distribution having a d 95 in the range from 140 μm to 250 μm; and
an average grain shape factor R a (Cu) of greater than or equal to 0.60, wherein the average grain shape factor R a (Cu) is obtained from the arithmetic mean of the shape factors R K of the individual grains, the shape factor R K of each individual grain being d K,ortho /d K,max , wherein d K,max is the maximum grain diameter and d K,ortho is the grain diameter running perpendicular to d K,max , determined on half the length of d K,max , and
wherein the coating composed of copper or a copper alloy is applied by means of a DCB process to the ceramic substrate.
2. The copper-ceramic composite of claim 1 , wherein the copper or the copper alloy has a number distribution of the grain sizes having a median d 50 in the range from 55 μm to 115 μm.
3. The copper-ceramic composite of claim 1 , wherein the d 95 is in the range from 140 μm to 230 μm.
4. The copper-ceramic composite of claim 1 , wherein the grain size number distribution of the copper or the copper alloy has a d 5 of greater than or equal to 15 μm.
5. The copper-ceramic composite of claim 1 , wherein the grain sizes of the copper or of the copper alloy are in the range from 15 μm to 250 μm.
6. The copper-ceramic composite of claim 1 , wherein the coating composed of copper or a copper alloy has a thickness D Cu and the grain size number distribution of the copper or the copper alloy has a median d 50 value, the ratio of the D Cu to the median d 50 value being in the range from 0.05 to 0.40, wherein the thickness D Cu and the median d 50 value have the same unit of measure for determination of the ratio of the D Cu to the median d 50 value.
7. The copper-ceramic composite of claim 1 , wherein the coating composed of copper or a copper alloy at least partly has structuring to form electrical contact areas.
8. The copper-ceramic composite of claim 1 , wherein the ceramic substrate contains an oxide, a nitride, a carbide or a mixture or composite of at least two of these materials.
9. The copper-ceramic composite of claim 1 , wherein the ceramic substrate contains at least 65% by weight of Al 2 O 3 .
10. The copper-ceramic composite of claim 1 , wherein the coating composed of copper or a copper alloy has a thickness in the range of 0.2-1.2 mm over at least 70% of its area.
11. A module containing at least one copper-ceramic composite according to claim 1 and one or more bond wires.
12. The copper-ceramic composite of claim 4 , wherein the d 5 is in the range from 15 μm to 80 μm.
13. The copper-ceramic composite of claim 10 , wherein the ceramic substrate has a thickness in the range of 0.2-1.2 mm over at least 70% of its area.
14. The copper-ceramic composite of claim 1 , wherein the ceramic substrate has a thickness in the range of 0.2-1.2 mm over at least 70% of its area.
15. The copper-ceramic composite of claim 1 , wherein the average grain shape factor R a (Cu) of the copper or the copper alloy is greater than or equal to 0.60 and less than or equal to 1.0.
16. The copper-ceramic composite of claim 1 , further comprising copper-aluminum spinels located between the ceramic substrate and the coating.
17. The copper-ceramic composite of claim 9 , wherein the Al 2 O 3 is in the form of grains, the grains having
grain sizes in the range from 0.01 μm to 25 μm; and
a grain size number distribution having a d 95 in the range from 4.0 μm to 15.0 μm.
18. The copper-ceramic composite of claim 9 , wherein the Al 2 O 3 grains have an average grain shape factor R a (Al 2 O 3 ) of greater than or equal to 0.40, wherein the average grain shape factor R a (Al 2 O 3 ) is obtained from the arithmetic mean of the shape factors R K of the individual grains, the shape factor R K of each individual grain being d K,ortho /d K,max , wherein d K,max is the maximum grain diameter and d K,ortho is the grain diameter running perpendicular to d K,max , determined on half the length of d K,max .