弱碱性抛光液中FA/O 螯合剂和H2O2对Ru CMP的影响研究

Ru作为一种新型阻挡层材料已经应用到了先进的集成电路生产中。但由于金属钌特殊的物理化学性质使其化学机械抛光(CMP)还存在很多问题。为了提高Ru的去除速率,本文研究了FA/O螯合剂和H2O2对Ru的抛光去除速率(RR)和静态腐蚀速率(SER)的影响。实验结果表明,随着H2O2浓度的增加,在抛光过程中,Ru表面形成了致密氧化层,导致Ru的抛光去除速率(RR)和静态腐蚀速率(SER)先增加后减少。通过电化学方法对Ru表面的腐蚀情况进行了分析研究。结果表明,FA/O螯合剂能通过与Ru的氧化物((RuO4)2- 和RuO4 )形成可溶性胺盐(R(NH3)4] (RuO4)2) 提高Ru 的去除速率。同时,为了降低金属Ru CMP后表面粗糙度,在抛光液中加入了非离子表面活性剂AD。

Effect of FA/O complexing agents and H2O2 on chemical mechanical polishing of ruthenium in weakly alkaline slurry

This paper investigated the effect of FA/O and hydrogen peroxide (H₂O₂) on ruthenium (Ru) removal rate (RR) and static etching rate (SER). It was revealed that Ru RR and SER first linearly increased then slowly decreaseed with the increasing H₂O₂ probably due to the formation of uniform Ru oxides on the surface during polishing. Their corrosion behaviors and states of surface oxidation were analyzed. In addition, FA/O could chelate Ru oxides (such as (RuO₄)^2- and RuO₄^- changed into soluble amine salts R(NH₃)₄] (RuO₄)₂) and enhance Ru RR. The non-ionic surfactant AD was used to improve the Ru CMP performance. In particular, the addition of AD can lead to significant improvement of the surface roughness.