Patent ID: 7646477
Filing Date: 2010-01-12
Classification: G01N,G03F

Abstract:
1. A pattern inspection apparatus, comprising: a light source which emits a deep ultraviolet laser having a wavelength no greater than 266 nm; an irradiator which irradiates said deep ultraviolet laser onto a specimen on which a pattern is formed through a polarization condition controller which controls a polarization condition of said deep ultraviolet laser and an objective lens; an imager which forms an image of said specimen irradiated with said polarization condition controlled deep ultraviolet laser and detects said formed image with a rear-surface irradiation type time delay image sensor through a glass cover, said image being set at an angle inclined to a surface of the specimen so as to prevent emergence of interference fringes at said glass cover caused by said deep ultraviolet laser; an image processor which processes a signal outputted from said sensor to detect a defect of said specimen having a size no greater than 0.07 μm by converting an analog image signal outputted from said sensor to a digital image signal with an A/D converter, by modifying the digital image signal with a gradation converter, and by removing noises from the modified digital image signal which are specific to the deep ultraviolet laser with an image filter; and a display which displays information of said defect detected by said image processor.