机械化学抛光中晶圆材料切削率和非均匀性有限元模型

摘要

提出了一个机械化学抛光中晶圆材料非均匀性的有限元模型.通过分析压力、摩擦力、抛光垫和承载膜的可压缩性对晶圆的应力分布的影响,研究了抛光过程中晶圆厚度的不均匀性.结果证明非均匀剪应力是晶圆厚度变化的一个主要原因.这个模型也建立了声发射信号的变化和晶圆厚度不均匀性的关系.通过对晶圆材料切削率的声发射信号监测,证明了实验结果和模型预测值的一致性.%A 3D finite element model is presented for wafer non-uniformity in chemicalmechanical polishing(CMP)process. Film thickness non-uniformity of the wafer during CMPprocess was investigated by examining the influence of applied pressure, friction force,pad andcarrier film compressibility on stress distribution across the wafer diameter. It shows that non-uniform shear stress distribution on wafer plays an important role on the non-uniformity. Themodel relates the variation of acoustic emission (AE)signal from non-uniform stress distribu-tion on the wafer to its non-uniformity. The agreement between model prediction and experi-mental results is demonstrated by AE monitoring of material removal rate in CMP process.