Inspection device for mask

Abstract

Abstract PURPOSE: To detect the defect of a mask instantaneously by projecting light from one side to the inside of the mask and by making the faulty part glitter on the surface of the mask on utilizing the diffused reflection which occurs only in the faulty part. CONSTITUTION: When the light projected from one side of the inside of the photomask passes through the glass plate 18 by the total reflection and emerges from the other side, no light is detected even when viewed from above as shown in Figure (a), the whole visual field looks dark. When there exists a defect 19, a portion of light projected to the glass plate 18 is diffusely reflected as shown in Figure (b) and the faulty part glitters when viewed from above or below. The presence or absence of the defect can be discriminated by the presence or absence of the diffused reflection of light. COPYRIGHT: (C)1980,JPO&Japio

Inventors

• 👤 Tamotsu Sasaki
• 👤 Moriaki Kurimoto

Bibliographic Details