MASK MANUFACTURING METHODS COMPRISING PATTERNS TO CONTROL CORNER ROUNDING

摘要

A method is provided for determining a measure of corner rounding produced in a mask structure. The method includes providing an un-patterned mask structure having a transparent substrate, an opaque layer on the substrate and a photoresist on the opaque layer. A corner rounding test pattern is etched into the photoresist. The pattern exposes underlying portions of the opaque layer. The pattern is in the shape of a pair of intersecting perpendicular lines of the photoresist. The exposed portions of the opaque layer are brought into contact with a etch to remove the exposed portions of the opaque layer and to thereby expose underlying portions of the substrate. In one embodiment, the etch is a wet etch and undercuts the photoresist to remove unexposed portions of the opaque layer disposed adjacent to the exposed portions of the opaque layer. The photoresist is removed to produce mask structure. A defect is produced in the opaque layer of the mask structure, such defect being produced as a result of rounded corners, rather than square corners. The defect is formed in the opaque layer in region at the intersection of the pair of intersecting perpendicular lines of the photoresist. The defect is measured to provide an indication of the degree of corner rounding. With such method, standard measuring equipment, such as line width measuring equipment of defect detecting equipment can be used to determine the degree of corner rounding being produced in the semiconductor structure being formed concurrently with the test pattern.