The influence of self-assembled disulfide additive on the pattern shape by Cu electrodeposition through mask

The influences of individual additives (bis-3-sodiumsulfopropyl disulfide (SPS) and Cl−) on the sidewall shape of Cu pattern were identified. The influence of self-assembled disulfide and related thiolates with various end-groups on the edge shape of Cu pattern was also explored. A tapered pattern could be formed during electrodeposition through mask with a Cu bath containing both SPS and Cl−. Cl− and sulfonate end-group of thiolate plays a key role in forming sloped sidewall of Cu pattern. Mechanism illustrating sloped sidewall of Cu deposit adjacent to photoresist mask during electrodeposition in a Cu bath containing SPS and Cl− was proposed in terms of self-assembled monolayers (SAMs) and electrochemical behavior of SPS and Cl−.