Applications Of Laser Microsurgery In Wafer Scale Integrated Circuit Manufacturing

Abstract

Theoretical and practical considerations for optimized laser microsurgery on semiconductor devices are presented and discussed. Various commercially available lasers suitable for microsurgery are described, although the present work centers around the use of a xenon laser. Along with a thorough discussion of the xenon lasers operating characteristics, a number of novel xenon laser-based failure analysis techniques developed in the wafer scale integration program at Trilogy Systems Corp. are reported. Over the past 10 to 15 years, laser technology has been used in semiconductor manufacturing technology to solve an increasing number of problems to which it is uniquely suited. Lasers have been successfully used in the areas of photomask repair, resistor trimming, cutting of redundant circuit links, laser formed connections, and failure analysis (1-4). The property of laser technology which makes it so useful is the ability to apply a relatively uniform dose of photonic energy (0.01 - 1.5 mJ) in a very short time (1nS - 1.5µS) to the microscopic areas of interest in integrated circuits (1 Am2 - 100 Am2) using more or less standard optical components. In this paper, several laser based techniques which have proven exceptionally useful in the production of fully functional wafer scale integrated circuit prototypes at Trilogy Systems Corp. are reported as well as the results of a study of the operating characteristics of the Florod L.F.A. xenon laser system used in this study.