Metal-ceramic substrate, method for the production thereof, and module
A metal-ceramic substrate which has a highly stable bond between the metal layer and the ceramic body, and also high thermal conductivity and electrical conductivity. The metal-ceramic substrate comprises (a) a ceramic body, (b) a metal layer, and (c) a bonding layer located between the ceramic body and the metal layer. The bonding layer comprises (i) a metal M1 having a melting point of at least 700° C., (ii) a metal M2 having a melting point of less than 700° C., (iii) a metal M3 selected from the group of active metals, and (iv) a metal M4 selected from the group consisting of bismuth, gallium, zinc, indium, germanium, aluminum and magnesium. The bonding layer has the following characteristics: (c1) M(M2) EDX =10-20 weight percent, (c2) 15 weight percent≤[M(M4)/M(M2)] ICP *1000 weight percent+M(M2) EDX ≤100 weight percent and (c3) M(Ag) EDX <10 weight percent.
1 . A metal-ceramic substrate comprising:
(a) a ceramic body;
(b) a metal layer; and
(c) a bonding layer located between the ceramic body and the metal layer, the bonding layer comprising:
(i) a metal M1, the metal M1 being copper;
(ii) a metal M2, the metal M2 being tin;
(iii) a metal M3 selected from the group consisting of hafnium, titanium, zirconium, niobium, tantalum, vanadium and cerium; and
(iv) a metal M4 selected from the group consisting of bismuth, gallium, zinc, indium, germanium, aluminum and magnesium,
wherein the bonding layer has the following features:
M
(
M
2
)
EDX
=
10
-
20
weight
percent
,
(
c1
)
15
weight
percent
≤
[
M
(
M
4
)
/
M
(
M
2
)
]
ICP
*
1000
weight
percent
+
M
(
M
2
)
EDX
≤
100
weight
percent
,
and
(
c2
)
M
(
Ag
)
EDX
=
<
10
weight
percent
,
and
(
c3
)
wherein:
M(M2) EDX is the content, in weight percent, of the metal M2 in the bonding layer, determined by means of Energy Dispersive X-Ray (EDX),
[M(M4)/M(M2)] ICP is the ratio of the content of metal M4 in the bonding layer to the content of metal M2 in the bonding layer, determined by means of Inductively Coupled Plasma (ICP),
M(Ag) EDX is the silver content, in weight percent, in the bonding layer, determined by means of EDX, and
the bonding layer exhibits an adhesive strength of at least 40 N/cm.
2 . The metal-ceramic substrate according to claim 1 , wherein the ceramic of the ceramic body is selected from the group consisting of aluminum nitride ceramics, silicon nitride ceramics, and aluminum oxide ceramics.
3 . The metal-ceramic substrate according to claim 1 , wherein the metal of the metal layer is copper.
4 . The metal-ceramic substrate according to claim 1 , wherein the metal M4 is bismuth.
5 . The metal-ceramic substrate according to claim 1 , wherein the bonding layer has the following feature:
M
(
M
2
)
EDX
=
10
-
15
weight
percent
.
(
c1
′
)
6 . The metal-ceramic substrate according to claim 1 , wherein the bonding layer has the following feature:
15
weight
percent
≤
[
M
(
M
4
)
/
M
(
M
2
)
]
ICP
*
1000
weight
percent
+
M
(
M
2
)
EDX
≤
70
weight
percent
.
(
c2
′
)
7 . The metal-ceramic substrate according to claim 1 , wherein the bonding layer has the following feature:
M
(
Ag
)
EDX
<
1
weigh
t
percent
.
(
c3
′
)
8 . A method for producing the metal-ceramic substrate of claim 1 comprising the steps of:
a) providing a stack containing
a1) a ceramic body
a2) a metal foil and
a3) a solder material that is in contact with the ceramic body and the metal foil, wherein the solder material comprises:
(i) the metal M1,
(ii) the metal M2,
(iii) the metal M3, and
(iv) the metal M4, and
b) heating the stack to obtain the metal-ceramic substrate.
9 . A module comprising the metal-ceramic substrate according to claim 1 .
10 . The metal-ceramic substrate of claim 1 , wherein the bonding layer is free of silver.
11 . The metal-ceramic substrate of claim 1 , wherein
the metal M3 is titanium; and
the metal M4 is bismuth.
12 . The metal-ceramic substrate of claim 1 , wherein
the metal M3 is a combination of titanium and zirconium; and
the metal M4 is bismuth.
13 . The metal-ceramic substrate of claim 1 , wherein
the metal M3 is titanium; and
the metal M4 is germanium.
14 . The metal-ceramic substrate of claim 1 , wherein the bonding layer exhibits an adhesive strength of at least 75 N/cm.
15 . The metal-ceramic substrate of claim 4 , wherein the bonding layer exhibits an adhesive strength of at least 75 N/cm.
16 . The metal-ceramic substrate of claim 1 , wherein the bonding layer exhibits an adhesive strength of greater than 100 N/cm.