Patent ID: 9717149
Date: 2017-07-25
CPC Classifications: H05K,Y10T

Claim:
1. A method for producing a ceramic circuit board having electric printed conductors and contact points on at least one of two sides and having at least one via, comprising the sequential process steps of: a) producing a ceramic substrate of aluminum nitride and creating a borehole at a location provided for the at least one via, b) filling the borehole with a first adhesive paste of copper, tungsten, molybdenum or their alloys or mixtures thereof, and c) one-pass overprinting using a first screen printing operation on at least one side of the ceramic substrate with a desired layout of the printed conductors and contact points using a second adhesive paste, d) firing the printed ceramic substrate in a firing oven with nitrogen, wherein an oxygen content is kept at a controlled level of 0-50 ppm O e) printing using a cover paste with a low glass content on the second adhesive paste in a second screen printing operation until achieving a desired thickness of the printed conductors and contact points, f) firing the printed ceramic substrate in a firing oven with nitrogen, wherein the oxygen content is kept at 0-50 ppm O