Analysis of Cu/Low-k structure under back end of line process

As the progress of the semiconductor process develops to achieve miniaturization and attain better performances for the electronic device, next-generation IC chips with deep sub-micron Cu/low-k stacked structures adopting the fabrication of (dual) damascene are developed to meet the urgent requirements of reducing high RC delay; the purpose of this is to obtain high-speed signal communication. However, due to poor adhesion and intrinsically lower fracture toughness of low-k materials as well as process loading that introduces flaws and delaminations, the phenomenon of crack growth is observed. To investigate the large scale difference problem, such as the back end of line (BEoL) structure to the silicon chip, a special multi-scale finite element simulation technology, global-local finite element method, is used to deal with this issue. The interfacial crack in the BEoL structure is modeled using the global-local technique. The chemical vapor deposition (CVD) process that induced loading to a micro crack in the interface between etch stop layer and metal track layer (ESL/Mx interface) will also be discussed through a statistical factorial design method in order to understand the crack growth phenomena that might occur during the BEoL process.