Described is a process for preparing a ceramic substrate bonded with a metal foil. Moreover, described is a metal-ceramic-substrate provided with a thick-film layer and the use of a thick-film paste for bonding a metal foil onto a ceramic substrate.

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).

The invention relates to a method for connecting at least two components (1, 2), comprising the following steps: A) providing at least a first component (1) and a second component (2), B) applying at least one donor layer (3) to the first and/or the second component (1, 2), wherein the donor layer (3) is enriched with oxygen (31), C) applying a metal layer (4) to the donor layer (3), the first or the second component (1, 2), D) heating at least the metal layer (4) to a first temperature (T1) such that the metal layer (4) is melted and the first component (1) and the second component (2) are connected to one another, and E) heating the arrangement to a second temperature (T2) such that the oxygen (31) passes from the donor layer (3) into the metal layer (4) and the metal layer (4) is converted to form a stable metal oxide layer (5), wherein the metal oxide layer (5) has a higher melting temperature than the metal layer (4), wherein at least the donor layer (3) and the metal oxide layer (5) connect the first component (1) and the second component (2) to one another.

Top and bottom metal plates of a DMB panel stack are simultaneously direct-bonded to the central ceramic sheet in a single high-temperature step. During this step, the DMB panel rests on an array of very small upwardly projecting ceramic contacts of a ceramic carrier. An amount of unoxidized carbon (e.g., a layer of graphite) is disposed on each contact projection such that an amount of carbon is disposed between the top of the contact projection and the metal oxide skin of the bottom metal plate. The carbon bonds with oxygen from the metal oxide skin, thereby preventing connection or direct-bonding of the ceramic contact projection to the second metal plate. This reduces imperfections in the metal of the bottom plate and reduces the amount of ceramic particles bonded to metal at contact sites. As a result, less post-bonding processing is required to make a high quality DMB substrate.

A ceramic/metal composite structure includes an aluminum oxide substrate, an interface bonding layer and a copper sheet. The interface bonding layer is disposed on the aluminum oxide substrate. The copper sheet is disposed on the interface bonding layer. The interface bonding layer bonds the aluminum oxide substrate to the copper sheet. Some pores are formed near or in the interface bonding layer. A porosity of the interface bonding layer is substantially smaller than or equal to 25%.