Method for determining the roughness of an inner layer

摘要

The method involves measuring a material parameter in layer-wise direction through the electrically nonconductive layer such as ceramic substrate layer (13) in transition region (10) of the outer electrically nonconductive layer and the internal metal substrate or metal layer (7), until the material parameter rises and reaches a maximum plateau value. The material parameter in the transition region is correlated with the predetermined roughness of the comparative samples.