THE SIMULATION OF CONTRAST-ENHANCED LITHOGRAPHY

Abstract

The Dill's parameters of nonlinear photobleaching materials of p-diazo-N,N-dimethylaniline chloride zinc chloride (DZC) and poly(di-n-hexylsilane) (PDHS) are irregularly dependent on their film thickness, and also their refractive indexes change during exposure. These difficulties make Dill's model inadequate for the simulation of nonlinear photobleaching materials used in contrast-enhanced lithography. A direct approach was proposed to solve these difficulties. Equations with four parameters were derived to simulate the nonlinear photobleaching curves of DZC, PDHS and other nonlinear photobleaching curves reported in literature. The equations correlated verv well with these curves by using best-fit parameters. Linearity was found with these four parameters in these equations as a function of film thicknesses of DZC and PDHS. Based on this linearity, the modelling and simulation of these nonlinear photobleaching materials as contrast-enhancement layers are more convenient and accurate than those using Dill's model.