CMP中铜的碟形缺陷的研究

Study on the dishing of copper in CMP

具体分析了铜的碟形缺陷并非由于抛光垫的弯曲造成,但是与抛光垫的表面形态有关,在此基础上,分析了铜CMP的作用机制,初步定性指出造成铜的碟形缺陷的原因,并对缺陷进行建模。比较了铜的碟形缺陷的电阻实际测量值和理论计算值,发现带碟形缺陷的电阻均大于理论值,并且随着铜的线宽增大,碟形缺陷也呈增大趋势。详细比较了选择性抛光液和非选择性抛光液对碟形缺陷的作用,从理论和测绘图形上证明选择性抛光液是造成碟形缺陷重要因素之一。采用了综合的工艺实验,最后得出抛光垫的种类及选择性抛光液在过抛光的情况下,是造成铜碟形缺陷的主要因素。

In this paper, the author concrete analysis the dishing of copper not due to the bending of the pad, but with the topography of the pad. The author analysis the CMP setup, and point out the possible reasons. The author builds the models of dishing. To compare with copper dishing resistance actual measurement and theoretical values, find the resistance with dishing is larger than theoretical, and with the increase of copper linewidth, the dishing is also increasing trend of defects. The author compare with selective and non-selective slurry, find the selective one is important factor to cause dishing. Finally the author do the integrated technology experiment, make sure both the selective slurry and topography of pad are the main factor to form dishing