RF etch pre-clean effect on PVD Al filling with low k SiLK IMD

A issue related with the integration of PVD Al metallization with low k SiLK dielectrics was investigated. SiLK polymer material was severely damaged during RF etch pre-clean step which was performed to remove the AlOx layer formed on Al line in via structure. The degraded SiLK surface affected strongly the texture of Ti and Al film and then promoted the agglomeration when thin Al film was deposited on via side wall. The improvement of Al filling ability was carried out with the optimized RF etch condition.