Method of manufacturing a metal-ceramic substrate (1) which, in the finished state, has a ceramic layer (11) and a metal layer (12) extending along a main extension plane (HSE) and arranged one above the other along a stacking direction (S) extending perpendicularly to the main extension plane (HSE) comprising providing the metal layer (12) and the ceramic layer (11) and bonding the metal layer (12) to the ceramic layer (11) in regions to form a first region (B1), which has a materially bonded connection between the metal layer (12) and the ceramic layer (11), and a second region (B2), in which the metal layer (12) and the ceramic layer (11) are arranged one above the other without a materially bonded connection, as seen in the stacking direction (S).

A substrate includes a ceramic sintered body, a first circuit plate and a second circuit plate. The ceramic sintered body contains Al, Zr, Y and Mg. In the ceramic sintered body, the Mg content in terms of MgO is S1 mass % and the Zr content in terms of ZrO.sub.2 is S2 mass %, a following formula (1) is established. When a thickness of the first circuit plate is T1 mm, a thickness of the second circuit plate is T2 mm, and a thickness of the ceramic sintered body is T3 mm, following formulas (2), (3), and (4) are established. Formula (1): −0.004×S2+0.171<S1<−0.032×S2+1.427; Formula (2): 1.7<(T1+T2)/T3<3.5; Formula (3): T1≥T2; and Formula (4): T3≥0.25.

The ceramic sintered body contains Zr, Al, Y, and Mg. A Zr content is 7.5 mass % or more and 23.5 mass % or less in terms of ZrO.sub.2. An Al content is 74.9 mass % or more and 91.8 mass % or less in terms of Al.sub.2O.sub.3. A Y content is 0.41 mass % or more and 1.58 mass % or less in terms of Y.sub.2O.sub.3. A Mg content is 0.10 mass % or more and 0.80 mass % or less in terms of MgO. A ZrO.sub.2 crystal phase as a crystal phase has a monoclinic phase and a tetragonal phase as crystal structures. When a thermal aging treatment is performed for 100 hours in an environment of 180 degrees C., a ratio of a peak intensity of the monoclinic phase to a sum of peak intensities of the monoclinic phase and the tetragonal phase is 15% or less in the X-ray diffraction pattern.

A direct bonded copper ceramic substrate is provided, which includes a nitride ceramic substrate, a first passivation layer, and a first copper layer. The first passivation layer includes aluminum oxide or silicon oxide doped with another metal. The other metal is titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, or a combination thereof. The aluminum or silicon and the other metal have a weight ratio of 60:40 to 99.5:0.5. The first passivation layer is disposed between the top surface of the nitride ceramic substrate and the first copper layer.

The invention relates to a copper-ceramic composite comprising:—a ceramic substrate;—a copper or copper alloy coating in which the copper or copper alloy has grain sizes of 10 μm to 300 μm and a number distribution of the grain sizes with a median d.sub.50 and an arithmetic mean d.sub.arith, the ratio of d.sub.50 to d.sub.arith (d.sub.50/d.sub.arith) being between 0.75 and 1.10.

In a ceramic sintered body, the Zr content is 17.5 mass %-23.5 mass % in terms of ZrO.sub.2, the Hf content is 0.3 mass %-0.5 mass % in terms of HfO.sub.2, the Al content is 74.3 mass %-80.9 mass % in terms of Al.sub.2O.sub.3, the Y content is 0.8 mass %-1.9 mass % in terms of Y.sub.2O.sub.3, the Mg content is 0.1 mass %-0.8 mass % in terms of MgO, the Si content is 0.1 mass %- and 1.5 mass % in terms of SiO.sub.2, and the Ca content is 0.03 mass %-0.35 mass % in terms of CaO. The total content of Na and K is 0.01 mass %-0.10 mass %, when the K content is converted to K.sub.2O and the Na content is converted to Na.sub.2O. The balance content is 0.05 mass % or less in terms of oxide.

The invention relates to a copper/ceramic composite comprising—a ceramic substrate which contains aluminum oxide, —a coating which lies on the ceramic substrate and which is made of copper or a copper alloy, wherein the copper or the copper alloy has a particle size number distribution with a median value d.sub.50, an arithmetic mean value d.sub.arith, and a symmetry value S(Cu)=d.sub.50/d.sub.arith; the aluminum oxide has a particle size number distribution with a median value d.sub.50, an arithmetic mean value d.sub.arith, and a symmetry value S(Al.sub.2O.sub.3)=d.sub.50/d.sub.arith; and S(Al.sub.2O.sub.3) and S(Cu) satisfy the following condition: 0.7≤S(Al.sub.2O.sub.3)/S(Cu)≤1.4.

A direct bonded copper ceramic substrate is provided, which includes a nitride ceramic substrate, a first passivation layer, and a first copper layer. The first passivation layer includes aluminum oxide or silicon oxide doped with another metal. The other metal is titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, or a combination thereof. The aluminum or silicon and the other metal have a weight ratio of 60:40 to 99.5:0.5. The first passivation layer is disposed between the top surface of the nitride ceramic substrate and the first copper layer.

The present invention relates to a copper ceramic substrate incorporating a ceramic carrier, and a copper layer joined to a surface of the ceramic carrier, wherein the copper layer incorporates at least one first layer, which faces the ceramic carrier and has an average first grain size, and a second layer, which is arranged on the face of the copper layer facing away from the ceramic carrier and has an average second grain size, the second grain size being smaller than the first grain size.

A method for producing a semi-finished metal product (2), in particular a semi-finished copper product, for a metal-copper substrate, in particular for a copper-ceramic substrate, including: providing a first metal layer (11), in particular a first copper layer, and a second metal layer (12), in particular a second copper layer, joining the first metal layer (11) and the second metal layer (12) to form the semi-finished metal product (2), wherein, chronologically before the first metal layer (11) is joined to the second metal layer (12) by means of different temperature treatments, a grain growth in the first metal layer (11) and/or the second metal layer (12) is initiated in such a way that in the produced semi-finished metal product (2), in particular in the produced metal-copper substrate, a first grain size in the first metal layer (11) differs from a second grain size in the second metal layer (12).