Robust porous SiOCH (k=2.5) for 28nm and beyond technology node

Robust p-SiOCH was deposited in a PECVD reactor using Si precursor with Si-C-C-Si bond structure. It achieved its elastic modulus of 8.4GPa at k=2.55, comparable to the reference silica-based p-SiOCH that has been widely evaluated among the major chipmakers. However, its post-integration k increase was ~0.1 on a 100nm-pitched single damascene line and negligible on a 90nm-pitched trench first metal hardmask dual damascene line. Its superb performance in plasma damage resistance without the sacrifice in its mechanical strength can be attributed to the presence of bridged carbon(s) between Si atoms in addition to the methyl functional group. According to ²⁹Si and ¹³C nuclear magnetic resonance (NMR) spectra, bridged carbon and carbon in the methyl group exist approximately in 1:1 ratio in the robust p-SiOCH.