碱性铜精抛液中表面活性剂ADS对平坦化效果的影响

Effect of the ADS Surfactant in the Alkaline Copper Precise Slurry on the Planarization

研究了阴离子表面活性剂十二烷基硫酸铵(ADS)在弱碱性铜抛光液中对晶圆平坦化效果的影响。对不同质量分数的阴离子表面活性剂ADS下的抛光液表面张力、铜去除速率、抛光后铜膜的碟形坑高度、晶圆片内非均匀性和表面粗糙度进行了测试。实验结果表明,当阴离子表面活性剂ADS的质量分数为0.2%时,抛光液的表面张力降低,铜的去除速率为202.5 nm·min^(-1),去除速率片内非均匀性减小到4.15%,抛光后铜膜的碟形坑高度从132 nm降低到68.9 nm,表面粗糙度减小到1.06 nm。与未添加表面活性剂相比,晶圆表面的平坦化效果得到改善。

The effect of the ammonium dodecyl sulfate（ ADS） as anionic surfactant on the wafer planarization in weak alkaline copper polishing slurry was investigated. The surface tension of the polishing slurry,removal rate of copper,the depth of dishing pit,the within-wafer non-uniformity of the wafer and the surface roughness of Cu film after polishing were tested with different mass fractions of anionic surfactant ADS. The experimental results show that when the mass fraction of anionic surfactant ADS is 0. 2%,the surface tension of the polishing slurry is reduced,and the removal rate of copper is 202. 5 nm·min^（-1） and the within-wafer non-uniformity of the removal rate is reduced to 4. 15%. Meanwhile,the depth of dishing pit is reduced from 132 nm to 68. 9 nm. The surface roughness of the Cu film is reduced to 1. 06 nm. The planarization effect of the wafer surface is improved as compared with the case where the surfactant is not added.