Patent ID: 6673526
Filing Date: 2004-01-06
Classification: G03F

Abstract:
A method of pattern formation comprising:irradiating light from an effective light source to a phase shifting mask, wherein said effective light source has a center portion, said center portion being 10 to 40% of an outer diameter of said effective light source, and with said irradiated light, transferring a pattern of the mask onto a substrate, wherein an amount of light emitted from said center portion of said effective light source is less than a peak amount of light emitted from peripheral portions of the effective light source by 2 to 90 percent; said method further comprising filtering light from said effective light source through an optical filter having a center portion corresponding to said center portion of said effective light source, said center portion of said filter having a first light transmittance and peripheral portions of said filter having a second light transmittance which is greater than said first light transmittance.