Research And Application Of Direct STI CMP Technology For 0.13μm And Beyond Process

Chemical mechanical planarization(CMP) technique is a key process enabling shallow trench isolation(STI) in semiconductor manufacture today,which is used in current integrated circuit manufacturing processes to achieve device isolation. When technology node has been developed to 0.13μm or beyond, the control of nitride loss on active area and dishing has become more and more critical, but conventional STI CMP can not meet such requirement. With the implementation of CeO2 based slurry with high removal rate and high selectivity, direct STI(DSTI) CMP has become the major process for 0.13μm and beyond high technology because of its excellent process performance, especially the strict control on nitride loss and dishing.The fundamental mechanism of CMP and STI CMP is introduced in this paper. The advantage and necessity of DSTI CMP are discussed by the comparison between STI CMP and DSTI CMP. The implementation of CeO2 based slurry is the basic of DSTI CMP. The polishing performance of three CeO2 based slurries from different producers is compared by the experiment on 0.13μm test wafers, and the slurry A is selected for the best performance. Based on the slurry A, a kind of two steps DSTI CMP process system was developed.The more stable thickness, better dishing and higher yield performance are achieved after this two steps DSTI CMP process applied in 0.13μm process line. By applying the endpoint system and improving the capacity of this system, process stability has been greatly improved, process time and cost largely reduced, and production line capacity also increased.