UV cure impact on robust low-k with sub-nm pores and high carbon content for high performance Cu/low-k BEOL modules

UV cure on robust low-k with sub-nm pore and high carbon content (R-ELK=Robust ELK) was studied to enhance the modulus of the film. UV cure helps to create Si-CH₂-Si bridging bond, which plays a role to enhance the modulus. UV cure does not affect the advantage of low PID (plasma-induced damage) and it was confirmed by C_int (interconnect capacitance) measurement for 80 nm pitch interconnect. Besides, UV cured R-ELK demonstrated high TDDB and EM reliability, with lifetime similar to the mature ULK baseline. High TDDB reliability with further dimensional scaling was also confirmed for the test structure with 20 nm spacing.