ULSI多层互连中W-CMP速率研究

Study on the Removal Rate of CMP for Tungsten Plug in ULSI

随着IC制造技术进入到亚深微米时代,化学机械抛光(CMP)工艺成为ULSI多层布线的关键技术之一。分析了W-CMP的机理,抛光液对W材料表面具有化学腐蚀和机械研磨的双重作用,对抛光速率有着重要的影响。在分析了抛光液中各组分的作用基础上,重点研究了专用的氧化剂、磨料、pH值调节剂和抛光液流量对CMP速率的影响,优化配制了高速率、高平整的碱性W抛光液。实验证明,抛光液流量为150mL/min,V(硅溶胶):V(水)=1:1,有机碱为5mL/L,活性剂为5mL/L,H2O2质量浓度为20mL/L时,能够获得较高的抛光速率,并实现了全局平坦化。最后对W-CMP中存在的问题和发展趋势进行了分析和展望。

Since the technology of IC developed to deep submicron era, CMP becomes the key process for building multilevel interconnections in ULSI. The mechanism of W-CMP was analyzed, the slurry makes a dual function of chemical erosion and mechanical lapping, has an important influence on the polishing rate. Based on the analysis of main effect of every component in CMP slurry, the factors such as oxidizer, abrasive, pH regulator and the flow velocity of polish slurry which affected polish speed were studied. As a result, new polishing slurry is achieved, which is of high polishing rate and high planarization. Experimental results show that the flow rates is 150 mL/min, V （SiO2 abrasives） ： V （H2O） = 1：1, organic alkali is 5 mL/L, active agent is 5 mL/L, H2O2 is 20 mL/L, the uniformity of rate become better, thus the global planarization is realized. Finally, the main problems and tendency about W-CMP was put forward.