A DIRECT APPROACH TO THE MODELING OF POLYDIHEXYLSILANE AS A CONTRAST ENHANCEMENT MATERIAL

Abstract

In our study the polydihexylsilane (PDHS), as a contrast enhancement material, we found that the values of A, B, and C of Dill's modeling parameters of PDHS are irregularly dependent on its film thickness, and also refractive index decreases during exposure. These difficulties make Dill's model inadequate for the simulation of contrast enhanced lithography. A new model was derived to simulate the nonlinear photobleaching curves of PDHS with varying thickness. Linearity was found with parameters in this equation as a function of PDHS film thickness. The thicker PDHS film does not improve the contrast within the usually used thickness range of 0.1-0.6-mu-m. This equation also models the nonlinear bleaching curve of p-diazo-N, N-dimethylaniline-chloride zinc chloride and the reported bleaching curve of CEM-2 quite well.