Low k adhesion issues in Cu/low k integration

Adhesion issues at different low k interfaces cause delamination during the copper CMP process. Delamination leads to other issues such as metal thinning, dielectric thinning and scratching. Critical fracture energy (K/sub c/) between substrate and low k and between low k and cap oxide have been investigated. Process optimizations of the spin coating and curing steps will improve substrate adhesion. A statistically-designed experiment was used to identify and isolate the factors affecting cap adhesion and was used to optimize cap adhesion.