Residual sintering stress measurement method for glass-ceramic substrates

摘要

Micro-Vickers indentation is applied to the measurement of the residual sintering stresses produced in glass-ceramic substrates with multilayer copper circuit traces. In this method, the ceramic stress is obtained from the difference in cracklengths produced on the substrates by the micro-Vickers indentation in the stressed and without-stress conditions.At first, the relation between stress and crack length is obtained by applying the method to glass-ceramic plates with a known stress produced by 4-point bending. Next, we discuss the conditions under which we can apply this method for substrates withmultilayer copper circuits. If the measurement is conducted very near to a copper layer, the crack produced bends toward the copper. From finite-element thermal stress analyses, we found that this bending is not caused by the residual stress distributionbut rather by the indentation-produced bending deformation of substrate where it is softened by the presence of the copper. The regions to which our method is applicable are restricted to those with distances of more than 50μm from the copper to preventsuch crack bending.