Photomask

Abstract

Abstract PURPOSE:To enhance the exposure workability of the photomask by forming a matching target on a transparent region of the mask and forming a filter for reducing the light transmitting amount of the exposure ultraviolet rays to zero or small amount in this region. CONSTITUTION:There are formed patterns for the matching Cr target 15 and for a circuit element 16 on a glass plate 14 having small thermal expansion coefficient for shielding light of less than 800mm. of wavelength. The filter 17 is formed within the plate 14 by a method of implanting ions partly to completely shield only the ultraviolet rays for exposure and to match them with visible light rays. With this mask the matching can be exactly conducted, but a target pattern may not be formed on a wafer. When it is preliminarily exposed and is then coated with a CVD film, is may be repeatedly used efficiently, and since it uses only one target on the wafer, the matching is accurate in a sequential superimposition so as to improve the yield of forming a semiconductor element.

Inventors

• 👤 Kazuya Kadota

Bibliographic Details