Dependence on Resist Stripping Efficiency to Irradiating Beam Size in Advanced Laser Resist Stripping Method

Abstract

Dependence on the stripping efficiency to irradiating beam size was investigated in an advanced laser resist stripping method. The beam size on the resist surface was changed from 0.3 mm to 3.0 mm. An intensity shape of the laser beam was Gaussian shape. At a beam diameter of 0.3mm, the stripped resist area in a beam was 15 % of 0.01 mm². In the case of beam diameter of 3.0 mm, the stripped resist area in a beam was 5 % of 0.38 mm². The stripped area improves 38 times for scale-up of the beam area of 100 times. The resist stripping efficiency was thought to depend on the heat stress due to a temperature gradient between the beam center and the regions without laser irradiation. Irradiation with multiple laser beams by small beam diameter was confirmed as one of the methods for improvement of a resist stripping rate with high efficiency.