低k材料的化学机械抛光研究

Study on CMP of Low-k Materials

阐述了低k材料在IC电路中的作用及其性质,以SiO2、SiOF、SiOCSP、SiOCNSP、Si-OCSO五种材料为研究对象,分析了低k材料与Cu互连工艺的相互联系和作用。在Sikder和Kumar提供的声发射信号(AE)的在线监测图的基础上比较和分析了五种材料的硬度和模数值;根据Preston方程绘制九点测量数据图,发现前三种材料可满足抛光机理,而后两种的抛光行为更倾向于表面反应;根据五种材料抛光前后的实验数据表面形态图表,判断出抛光后材料粗糙度的走向。最后指出低k材料需要发展和完善的工艺及对抛光设备的进一步要求。

The role and characterizations of low-k materials in IC circuits were introduced, and the interrelation between copper and low-k materials were analyzed to identify five materials including SiO2, SiOF, SiOCSP, SiOCNSP, SiOCSO as study objects. Based on AE test online provided by Sikder and Kumar, the hardness and modulus of five materials were compared and analyzed. It is found that the first three materials suit polishing mechanism and the other materials tend to surface reaction by Preston＇s equation. Based on the experimental data of the unpolished and polished materials, a table of surface morphology results was formed, which could judge a similar trend of polished roughness. The technologies to be improved and further demands for polishing equipements were presented.