Induced stresses and structural changes in silicon wafers as a result of laser micro-machining

Laser micro-machining has proven to be a very powerful and successful tool for precision machining and micro-fabrication with applications in electronics, MEMS, medical, and biomedical fields. A large number of studies were devoted to the investigation of laser-based micro-machining covering the different aspects of the machining process. Induced stresses due to laser micro-machining process were, however, not fully investigated. In this paper, we report, for the first time, the results of utilizing micro-Raman spectroscopy as a powerful stress measurement technique in investigating stresses as well as structural changes induced in a silicon single crystal wafer as a result of laser micro-machining. It was found that laser machining of silicon wafers has induced tensile stress in the range 0.8-1.0 GPa. The machining process has also led to the creation of as much as 14% amorphous silicon in the machined area. (C) 2002 Elsevier Science B.V. All rights reserved.