CMP characteristics of IGZO thin film with a variety of process parameters

Abstract

Recently, amorphous indium gallium zinc oxide (a-IGZO) is studied in the field of 3D transistor as a channel material for the high mobility, good uniformity and low leakage current performance. CMP process need be applied to fully remove surface IGZO in multilayer film stack structure and achieve the purpose of planarization. As we all know, the CMP characteristics of desired removal rate with stability and within-wafer non-uniformity (WIWNU%) play an important role in CMP process. In this paper, the variation of the removal rate and the non-uniformity for IGZO thin film were studied with various process parameters (such as polishing time, slurry flow rate, slurry dilution, head pressure, head and table speed).The results mean that the removal rate and the non-uniformity of IGZO thin film can be tuned by changing process parameters, which can enhance the confidence about the feasibility of IGZO-CMP in the application of advanced technology.