ULSI Wiring Formation by Copper Electroplating

摘要

Copper filling in sub-0.5 μm and 50 μm features by using copper electroplating, and electrochemical studies for several additives (bis (3-sulfopropyl) disulfide disodium salt (SPS), bis (2-sulfoethyl) disulfide disodium salt (SES), 2-mercaptopropanesulfonic acid sodium salt (MPS) and 2-mercaptoethanesulfonic acid sodium salt (MES)) are described. Copper filling in sub-0.5 μm features are accomplished by electroplating at 1 A/dm~2 in a copper sulfate solution containing Cl~- -PEG-SPS or Cl~- -PEG-SES. Moreover, copper filling in 50 μm features (aspect ratio 3) are accomplished by controlling the current waveform during copper electroplating in a copper sulfate solution containing Cl~- -PEG-SPS-Janus Green B (JGB). The acceleration effect of SES on copper deposition is nearly equal to that of SPS. For the purpose of copper filling in sub-0.5 μm features by electroplating, it is considered that the brightener that have disulfide group in the molecular, such as SPS and SES, is effective.