As discussed in earlier projects Low Temperature Co-fired Ceramics provide a means of making, in the truest sense, printed circuits. There is only one problem. One huge problem. When the raw materials are heated in a furnace the materials shrink. That means that if one wishes to fabricate a multilayer PCB using LTCC then it is necessary to have very precise formulations of the materials and processes to have any expectation of success at the end. This leaves the primary application of LTCC for those high performance PCBs where the high performance offered justifies the effort involved.
While not a universal solution, there are several ways in which shrinkage may be eliminate or minimized, it's called constrained sintering. If the grain size of the ceramic particles is confined to a narrow range, say 10 microns then shrinkage can be minimized. Hereaus hold patents on this method, they call it "Zero Shrink".
The second method is to deposit the green ceramic onto a surface that does not change dimensions during the sintering process. In this case Alumina.