Cu/ULK integration using a post integration porogen removal approach

This paper is focused on a new integration scheme to perform Cu/porous ULK interconnects. The dielectric (composite material made of porogen nano-particles dispersed in a MSQ matrix) is integrated in its non-porous state, preventing integration issues inherent in porous material. The porosity is only created after integration by a final thermal degradation of the porogen phase. Material, curing and processes compatibilities have been studied in order to perform single damascene interconnects. Electrical results prove the feasibility of this approach, showing that the porogen can be preserved during the integration and removed after the integration.