Abstract
In the present paper, simulations of photoresist pattern during proximity exposure, using measured values for the dissolution rate in the photoresist, are reported. We adopted the van Cittert-Zernike theory and Hopkins equation as a model of the radiation intensity distribution in photoresist during proximity exposure, and used a film thickness measurement system to measure the film thickness of photoresist during development as a means of determining the dissolution rate. The results of simulations pattern were then compared with SEM observation results to examine the validity of this method.
As experiments to corroborate the validity of this simulation method, a diazonaphthoquinone (DNQ)-novolac positive thick-film resist (hereafter referred to as “thick film resist") was used in patterning with a broad-wavelength (350 nm to 450 nm) mask aligner, and SEM observations were performed. In addition, simulations were conducted, and the resulting shapes were compared. Agreement was observed between the SEM observation results and the simulation results, and the differences in shapes for rough pattern dimensions and for fine pattern dimensions could be calculated. This indicates the validity of the proposed method.
