GRAY TONE MASK BLANK, GRAY TONE MASK, AND METHOD FOR FORMING PROCUCT PROCESSING MARK OR PROCUCT INFORMATION MARK

摘要

PURPOSE: A gray-tone mask blank, a gray-tone mask, and a method for forming a product process mark or a product information mark are provided to reduce a reflectivity of a light semi-transmission unit by forming a reflection protection film on a semi-transmission film. CONSTITUTION: A semi-transmission film(2) and a shading film(3) are successively formed on a transparent substrate(1). The semi-transmissive film and the shading film function as the semi-transmissive unit(21) and the shading unit of a gray-tone mask. A gray-tone mask forms an alignment mark or a mask information mark by etching the semi-transmissive film and the shading film. A transmissive film(11) is formed by removing the semi-transmissive film and the shading film.