A yield improvement program using process control and process optimisation for particle reduction using in situ particle monitoring on a Semitool Magnum

Abstract

Semitool, HYT/Pacific Scientific and MOS4YOU/Philips Semiconductors decided to investigate in close co-operation the process control and process optimisation through particle reduction on a Semitool Magnum wet clean system, by use of an In Situ Particle Monitor (ISPM). This is a new application for ISPM, for Semitool and for Philips. The goal of the co-operation is to evaluate the ISPM, to interpret the data generated and to improve the overall performance of the wet clean system. The ISPM detected wafers which were not cleaned properly as well as wafers which were not properly dry etched in a previous production step. Furthermore, the ISPM allowed us to improve the cleaning process, by improving the cleaning cycle of the chemical. Hereby, the ISPM proved to be a valuable tool for process control and process improvement. As particles are the main source for yield loss, the impact of a particle reduction program on yield is straightforward.