化学机械抛光中抛光垫的研究

抛光垫是化学机械抛光(CMP)系统的重要组成部分。它具有贮存抛光液，并把它均匀运送到工件的整个加工区域等作用。抛光垫的性能主要由抛光垫的材料种类、材料性能、表面结构与状态以及修整参数等决定。本文介绍CMP过程常用的抛光垫材料种类、材料性能、表面结构，总结了抛光垫的性能对CMP过程影响规律，认为：抛光垫的剪切模量或增大抛光垫的可压缩性，CMP过程材料去除率增大；采用表面合理开槽的抛光垫，可提高材料去除率，降低晶片表面的不均匀性；抛光垫粗糙的表面有利于提高材料去除率。对抛光垫进行适当的修整可以增加抛光垫表面粗糙度、使材料去除率趋于一致。与离线修整相比较，在线修整时修整效果比较好。

STUDY ON THE PERFORMANCES OF POLISHING PAD IN CHEMICAL-MECHANICAL POLISHING

Polishing pad is a very important component of the chemical-mechanical polishing (CMP) system. It delivers slurry to the wafer workpiece and provides part of the mechanical action in the CMP process. The performances of a polishing pad are determined by the type and properties of pad materials, the surface structure and state as well as the conditioning parameters. This paper introduces the type and properties of pad material, the surface structure currently used and summarizes the effects of the polishing pad on the CMP process. The summarization shows that the material removal rate increases with lower shear modulus and higher compressibility of the polishing pad. Using the polishing pad with grooves or rougher surfaces can increase the material removal and planarization rate. Pad conditioning, especially on-process conditioning, can improve the surface performances, resulting in efficient improvement in the material removal and planarization rate of CMP.