The Electrochemical Study of Polish Pad and Slurry on Cu/Ru Chemical Mechanical Polishing

• Main Authors: Chung-An Tsai, 蔡崇安
• Other Authors: 顏溪成
• Format: Others
• Language: zh-TW
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/55082851074215573444

碩士 === 國立臺灣大學 === 化學工程學研究所 === 103 === In this study the chemical mechanical polishing of copper and ruthenium in hydrogen peroxide and ammonium persulfate system has been investigated. Hydrogen peroxide or ammonium persulfate was employed as an oxidant in slurries. Either dish scrubber or regular polishing pad was used as polish pad. First, ruthenium was plated on a rotating disk electrode in a three electrode-system containing ruthenium chloride, and it would be used for chemical mechanical polishing. From the chemical mechanical polishing experiments, the experimental results showed that ammonium persulfate-based slurries at pH 6 had the best performance. Removal rate for copper and ruthenium with abrasion by dish scrubber was 365 nm/min and 92.4 nm/min and the removal selectivity was 3.95. Besides, the copper surface roughness reduced to 21.2 nm; the ruthenium surface roughness reduced to 43.5 nm. The removal rate for copper and ruthenium with abrasion by polishing pad (No. 40-7218, Buehler) was 355.4 nm/min and 63.95 nm/min and the removal selectivity was 5.55. The copper surface roughness was reduced to 14.3 nm and the ruthenium surface roughness was reduced to 19.03 nm. Due to the presence of ammonium ion in the ammonium persulfate solution, it could chelate and form copper complexes, and then accelerated the rate of dissolution. In the case that hydrogen peroxide solution was employed as an oxidant in slurries. 5 wt% of hydrogen peroxide in the slurries had the best performance. Its removal rate for copper and ruthenium was 207 nm/min and 85.26 nm/min, respectively, and its removal selectivity was 2.43. After chemical mechanical polishing, the copper surface roughness was reduced to16.8 nm and the ruthenium surface roughness was reduced to 32.1 nm.