Birefringent Tape-A New, Easier Technique for Seperating Thin Film and Printed Circuit Master Drawings with Perfect Registration

Abstract

A novel, easier technique is described for separating thin film and printed circuit master drawings with near-perfect registration for microelectronic production-masking purposes By employing inexpensive, readily manufactured, and easily identifiable strips or rolls of adhesive-backed transparent birefringent plastic tape, there results a more accurate, less costly, less tedious, and less time-consuming method of separating up to six zero-registration circuit configurations from a single master artwork original. Using ordinary incandescent lamps, two small off-the-shelf rotatable polarizing filters, and a good quality reduction camera, each component-type or other desired circuit configuration is photographically separated in quick succession with required near-zero error registration marks by taking advantage of the known angular rotation of the plane of polarization characteristic of each type of birefringent tape. Simple, straightforward directions for draftsmen and technicians can be readily developed from the description of the technique.