Development and optimization of porous pSiCOH interconnect dielectrics for 45 nm and beyond

A porous pSiCOH interconnect dielectric with a dielectric constant k=2.4 has been developed from mixtures of a SiCOH skeleton precursor and bicycloheptadiene (BCHD) and optimized for successful integration in the interconnect structure of 45 nm ULSI chip. The ulk pSiCOH is characterized by small pores, low pore connectivity, and excellent electrical properties. This paper describes the selection of the precursors, the optimization process and the properties of the optimized pSiCOH. The film has been qualified for integration in three 2X dual damascene metallization levels of 45 nm interconnects.