Electron-beam lithographic pattern generation system

Abstract

An electron-beam lithographic system has been evolving over the past few years at the IBM Research Laboratory in Yorktown Heights, New York. Several versions are now operational in the Yorktown Laboratory, and one in the IBM San Jose Laboratory. Many novel features which create a high degree of automation have been incorporated into each of these systems. This paper describes a pattern generator which was designed to allow a highly compact word syntax for transmission of stored mask information from a small computer, while the computer concurrently controls other system functions. The pattern generator is arranged to write shapes a minimum of data transfer. After initialization, only the origin and size of the first shape need be specified to begin execution. Then, if any parameters pertaining to a shape remain unchanged for the following shape, only the changes need be transmitted to cause the fill routine to operate. Predefined shapes (rectangles, parallelograms, triangles,...) are microcoded into the Generator and are directly invoked during the writing of a mask. A feature which provides still greater flexibility allows dynamic loading a microcode defining cells containing shapes whose perimeter may be irregular or curved. In addition, all these features may be written in an orientable array by giving a few machine instructions. This allows the repetition of millions of similar shapes with but a few transmitted words. The organization of the pattern generator is described, as well as integration with the remainder of the system to provide high-speed addressing of a 16K×16K array of points.