| 摘要 |
PURPOSE:To measure the distance between a mask and an object to be exposed. CONSTITUTION:The distance between a light transmissive mask 11 and an object 10 to be exposed is measured in such a way that the mask 11 and the object 10 are arranged and light is made incident to the surface of the mask 11 opposite to the object 10. Then the reflected rays of light from the surfaces of the mask 11 and object 10 are received and the interference fringes formed by the reflected rays of light are discriminated. |
