Patent ID: 6548226
Filing Date: 2003-04-15
Classification: G03F

Abstract:
A photolithographic process for patterning a photoresist layer over a substrate, comprising the steps of:forming a positive photoresist layer over the substrate, wherein the positive photoresist layer contains a photoacid generator and a photobase generator; changing the photoacid generator in the photoresist layer into photoacid and the photobase generator into photobase by shining a light source through a photomask, wherein the photomask has a first pattern region and a second pattern region that correspond with a first region and a second region of the photoresist layer, and the first pattern region has a duty ratio greater than the second pattern region so that the first region is exposed to a higher light intensity than the second region; and developing the positive photoresist layer; wherein the reaction threshold for turning the photobase generator into photobase is adjusted according to the exposure strength between the first region and the second region so that the quantity of photobase generated in the first region is much greater than in the second region, and ultimately, the diffusion of photoacid within the first region is blocked without affecting the development of the positive photoresist layer in the second region.