Analysis of Resist Removal Phenomenon Using Laser Irradiation

Resist removal phenomenon with laser irradiation was analyzed by using a finite element (FE) method. Laser irradiation in the water can improve the resist removal effect as compared with that of normal atmosphere irradiation. A two-dimensional (2-D) micro-FE model was constructed based on the boundary surface between the Si wafer, resist and water during laser radiation. In the normal atmosphere, any effective stress did not occur along the x-axis direction in the resist. In contrast, for the laser irradiation in the water, large compressive stress was confirmed along the x-axis direction in the resist. This compressive stress in the resist is thought to improve the resist removal efficiency.