Quantifying stresses induced by laser micromachining using micro-Raman spectroscopy

Abstract

Laser micromachining has proven to be a very successful tool for precision machining and microfabrication with applications in electronics, MEMS, medical, and biomedical fields. Stresses induced by the laser micromachining process can become an important factor during the micromachining process. In this paper, we report the results of utilizing micro-Raman spectroscopy to investigate the stresses and induced structural changes in a silicon single crystal wafer as a result of laser micromachining with nanosecond lasers (both UV and IR) and femtosecond lasers. These results show a strong dependence of induced stresses and amorphization on the laser machining conditions. The application of Raman spectroscopy as a quantitative characterization technique to further develop an understanding of the induced stress as a function of machining parameters including pulse repetition rate, pulse energy, pulse duration and machining speed will be discussed in detail.Laser micromachining has proven to be a very successful tool for precision machining and microfabrication with applications in electronics, MEMS, medical, and biomedical fields. Stresses induced by the laser micromachining process can become an important factor during the micromachining process. In this paper, we report the results of utilizing micro-Raman spectroscopy to investigate the stresses and induced structural changes in a silicon single crystal wafer as a result of laser micromachining with nanosecond lasers (both UV and IR) and femtosecond lasers. These results show a strong dependence of induced stresses and amorphization on the laser machining conditions. The application of Raman spectroscopy as a quantitative characterization technique to further develop an understanding of the induced stress as a function of machining parameters including pulse repetition rate, pulse energy, pulse duration and machining speed will be discussed in detail.