Forming an Insulating Skin on Conducting Ceramic Composite
Original Publication Date: 1987-Jul-01
Included in the Prior Art Database: 2005-Feb-01
In certain electronic components it is desired to join an active device to an insulating ceramic substrate. If that substrate happens to be a conducting ceramic composite, it must be overlayed with an insulating layer. This layer has adhesion and stress problems. The need for an added insulating layer can be avoided by creating an insulating skin on the ceramic composite by deeply etching away the conducting portion of the composite. This leaves the insulating network structure as insulating layer, and forms micropores for the enhanced adhesion of the next layer. An example of this idea is a composite made of conducting titanium carbide in an aluminum oxide insulating network. One effective removal method is to make the substrate the anode in an electrolyte of 5% sodium phosphate tribasic and 5% sodium chloride.