Patent EP-2447235-A1 (EP)
Title: Metal-ceramic substrate and method for manufacturing such a substrate
Inventor: MEYER ANDREAS DIPL-ING
IPC: B82Y30/00
Filed: 2011-10-13
Abstract: The metal-ceramic substrate comprises a first outer metal layer (4) forming a first surface side of the metal-ceramic substrate, and a second outer metal layer (5) forming a second surface side of the metal-ceramic substrate. The outer metal layers are connected by flat bonding with the surface sides of a plate-shaped substrate body, which consists of two ceramic layers (2) to obtain improved mechanical, thermal and electrical properties and a single intermediate layer (3) spaced apart form the ceramic layer. The metal-ceramic substrate comprises a first outer metal layer (4) forming a first surface side of the metal-ceramic substrate, and a second outer metal layer (5) forming a second surface side of the metal-ceramic substrate. The outer metal layers are connected by flat bonding with the surface sides of a plate-shaped substrate body, which consists of two ceramic layers (2) to obtain improved mechanical, thermal and electrical properties and a single intermediate layer (3) spaced apart form the ceramic layer. The intermediate layer: forms an inner metal layer (3.1); is connected with the ceramic layer; is arranged between the ceramic layers; and extends itself over the total surface side of the ceramic layers adjoining the intermediate layer. A layer thickness of the intermediate layer is greater than the layer thickness of the outer metal layer and/or the thickness of one of the ceramic layers. The intermediate layer is formed with two inner metal layers and/or one of the inner metal layers and an inner insulating layer having an inner ceramic layer. The inner layers forming the intermediate layer are connected together by the flat bonding. The intermediate layer is formed with: the inner insulating layer arranged between the two inner metal layers; and a recess for forming a channel or a chamber for receiving released gas- and/or vaporous and/or liquid components during the bonding. The recess is opened at a circumferential side of the metal-ceramic substrate. The intermediate layer comprises two inner metal layers that are provided in one of the metal layers and the recess. The recess and/or its inner space are opened at a side of the inner metal layer on which the inner metal layer is connected with a further layer to the intermediate layer. The recess and/or its inner space of the adjacent ceramic layer are separated by a bottom forming the inner metal layer. The metal-ceramic substrate comprises a breaking strength, which is greater than the breaking strength of an individual ceramic layer whose layer thickness is equal to the sum of the layer thickness of the two ceramic layers spaced apart through the intermediate layer. The metal layer forming the intermediate layer or its material has a Brinell hardness of less than 40. The inner metal layers forming the intermediate layer are connected with an adhesive- or peel strength of greater than 10 N/mm with each adjacent ceramic layer. A plated through-hole is provided into the ceramic layers spaced apart from one another, where the through-hole connects the outer metal layer arranged on the ceramic layer or a metal layer region of the outer metal layer is mechanically, thermally and/or electrically connected with the inner metal layer. The metal-ceramic substrate comprises a voltage- or dielectric-strength of 18 kV/mm. A connection between the adjacent layers is produced by direct copper bond-bonding and/or active soldering and/or hard soldering and/or using polymer- or epoxy resin-based adhesives, with fibers and/or using an electrically conductive adhesive. An independent claim is included for a method for producing a metal-ceramic substrate.