The carrier gas and surface passivation effects on selectivity in chemical vapor deposition of copper films

Abstract

One of the interesting areas of Cu–CVD is the selective deposition, which attracts more attention based on its potential as a patterning method of Cu. The selectivity of CVD–Cu for SiO 2, TiN, and Al substrates was investigated systematically using (hfac)Cu(VTMS) with carrier gas of H 2 and Ar in the absence or presence of surface passivation process using HMDS as functions of the deposition temperature (150–200°C) and deposition time. The apparent incubation time on each substrate was increased as the conductivity of substrates and the deposition temperature were decreased. Moreover, H 2 carrier gas induced a shorter incubation time than Ar carrier gas for all conditions. HMDS in situ predosing process lengthened the incubation time on each substrate, temperature, and carrier gas. Its increment was larger on SiO 2 than TiN substrates, and was also larger under Ar than H 2 carrier gas ambient. It is thought that there is some competition between –OH passivation effect and –OH increment effect in the case of HMDS dosing under H 2 carrier gas atmosphere, but only the passivation effect is working under Ar carrier gas atmosphere.