A laser machining system for making integrated circuit masks

An automatically controlled laser machining system for cutting integrated circuit masks in thin films deposited as fused silica substrates is described. A high-pressure helium-neon pulsed laser is used for cutting precision edges and a continuously operated carbon-dioxide laser is used for fast machining of larger areas in the mask. Details of the machining speeds and edge precisions obtained with each laser are given. The requirements for machining masks with the aid of both lasers are discussed. Results obtained in cutting test masks are presented and it is shown that considerable saving in machining times can be effected using the system of two lasers. The need for a vector generator, to control the movements of the work tables, as a peripheral to a computer is explained. Details of an experimental high-level mask-making computer language used with the above system are given.