Study On Gray-scale Mask Design System

Gray-scale mask technology is one of the most effective methods to fabricate three-dimensional micro/nano-structures in micro-electromechanical system. The gray-scale mask design is the key of gray-scale mask technology. However, the existing methods for gray-scale mask design are just applied to the specific regular patterns, such as circle concave lens, rectangular convex lens and rectangular wedge. In this paper, a novel algorithm used for gray-scale mask design of arbitrary shaped pattern is proposed and realized into program. A gray-scale mask design system is constructed.Gray-scale unit is generated by the PWM of coding theory in the gray-scale lithography. Paving unit is generated by paving method in finite element analysis. Based on the coding theory and the paving method, the paving method for gray-scale mask design is proposed. Four key problems of algorithm, which are the generation method of gray-scale units, the closure method of paving units, processing method of intersecting gray-scale units as well as generation method for boundary of the new paving layer, have been discussed. And algorithmic evaluations for gray-scale mask design are given.The computer program of this algorithm is developed by ObjectARX in the platform which is set up by Visual Studio2008and AutoCAD2010. Key modules and basic operational process are described in detail. A small scale graphic library of gray scale masks has been constructed by the program. Twelve examples of regular shaped patterns and three of arbitrary shaped patterns are taken out from the graphic library. And analyses of these examples are accomplished based on the algorithmic evaluation. The results indicate that the system is applied to design gray-scale mask with arbitrary shaped pattern efficiently. The method presented in this paper takes advantage of simple design program, and provides technology accumulation for the fabrication of three-dimensional micro/nano-structures.