Method for Measuring Semiconductor Lithographic Tool Focus and Exposure
Original Publication Date: 1987-Jul-01
Included in the Prior Art Database: 2005-Feb-01
An automated technique for selecting the optimum focus and exposure settings for a semiconductor photolithographic exposure system and for evaluating the performance of the associated focus and exposure control subsystem of the semiconductor photolithographic exposure system is presented. The reported technique is faster and more accurate than visual techniques which rely on operator judgement and faster and less costly than techniques that employ scanning electron microscopes. The technique is based on a quantitative evaluation of the characteristics of developed photoresist images and their edge slopes on a semiconductor wafer in exposed photoresist material.