Delamination Criteria for SiN/TiW Interfaces Tested by Cross-Sectional Nanoidentation and by Four Point Bending

Abstract

Interfaces between different material layers are potentially weakest links of microelectronic devices. Therefore, reliable criteria for delamination of structures are required as prerequisite of design optimization. In the present article, delamination of adjacent material layers is studied experimentally and by FEM simulation. An interface between SiN and TiW was delaminated by Cross-Sectional Nanoindentation (CSN) and by Four Point Bending. The adhesion energy observed during CSN is determined by FEM simulation using a method of equivalent loads, which compares CSN with a peel test. In a second approach, delamination during Four Point Bending is simulated by Mixed Finite Elements based on Strain Gradient Elasticity. The Mixed Elements were implemented in ABAQUS with user subroutine UEL. In this approach, the delamination criterion can be defined with use of a critical elastic energy density. The accordance between experiments and theoretical models is demonstrated.