Controlling of microloading effect of polysilicon etching in high density ECR etcher

As device densities increase, the device CD (critical dimension) bias difference between dense and isolated areas becomes a crucial problem for current 0.35 mu m logical device technology and beyond. The contribution to the CD bias difference not only comes from photolithography but also from plasma etching process. This paper is from fundamental etching mechanism point of view to describe where the microloading comes from for the polysilicon etching in an ECR etcher. The experiment based on the mechanism proposed was carried out and scanning electron microscope (SEM) profile results show that the microloading for dense and isolated area can be controlled to a minimum.