XYTOLR - A Computer Program for Integrated Circuit Mask Design Checkout

T h e increasing size a n d complexity of large-scale i n t e g r a t e d circuit mask designs h a s created a d e m a n d for c o m p u t e r aids to t h e circuit designer. W i t h o u t such aids, t h e design of many circuits would be not merely difficult, b u t practically impassible. Perhaps t h e best established design aids in t h i s field a r e c o m p u t e r art work generation systems, which accept as input numerical descriptions of m a s k layouts, and drive high-precision graphical o u t p u t devices which create t h e mask masters. X Y M A S K / ' * used at Bell Laboratories, is such a system. T h e use of a c o m p u t e r art work generation s y s t e m implies t h a t t h e r e exists a complete a n d u n a m b i g u o u s machine-readable description of t h e m a s k s required to produce an integrated circuit. In principle, this i n f o r m a t i o n , together with t h e physical properties of t h e s u b s t r a t e a n d diffused layers, is sufficient to predict any desired p r o p e r t y of t h e completed circuit. T h e availability of computer programs to predict a n d analyze i m p o r t a n t properties of circuit designs in a d v a n c e of their fabrication would be a m a j o r aid to t h e circuit designer. O n e early phase of t h e design process for which a c o m p u t e r aid is highly desirable is t h a t of checking a mask set, before it enters production, for compliance with design rules a i c h as required clearances between a r e a s delineated by t h e s a m e or different masks.