The synthesis of simulation programs used in CCD design

XAS, an expert system that automatically synthesizes charge coupled device (CCD) simulation programs, has knowledge about the characteristics of CCD chips and the way to write simulation programs. The authors discuss the problems of writing simulation programs and justify the use of an expert system to solve these problems. They describe the module structure of XAS and the type and usage of knowledge that every module has. Using this knowledge, together with mask data and process data which have been entered by the designer, XAS divides regions appropriately and then extracts functions for every region. By merely selecting the purpose of this simulation, the system automatically synthesizes a simulation program with relevant parameters. Currently, 70 to 80% of the CCD chips manufactured by the Sony Corporation are designed with the help of XAS. By using XAS, the design time has been cut to one third of the original