Research and solution of STI CMP dishing and uniformity improve for 28LP

CMP is becoming an enabling technology to meet the demands of precise machining of wafer surface in various applications. In this paper, dishing and uniformity performance of an 28nm STI-CMP process was studied with the influence of machine, slurry, polish pad, polish time, zone pressure and retaining ring force are analyzed, which affects the surface geometric parameter of silicon wafer. The results of experiment indicate that STI dishing, uniformity and wafer loading of silicon wafer are improved, by using new slurry with low SiN removal rate, controlling zone pressure, adjusting retaining ring force.