Proceedings of the
9th International Conference of Asian Society for Precision Engineering and Nanotechnology (ASPEN2022)
15 – 18 November 2022, Singapore

Recent development of laser microprocessing for silicon substrate

Xinxin Li1 and Yingchun Guan1,2,a

1School of Mechanical Engineering and Automation, Beihang University, 37 Xueyuan Road, Haidian District, Beijing, 100083, China

2National Engineering Laboratory of Additive Manufacturing for Large Metallic Components, Beihang University, 37 Xueyuan Road, Haidian District, Beijing, 100083, China


Silicon wafer has been widely used in semiconductor applications including computer systems, telecommunications equipment, automobiles, consumer electronics, automation and control systems, analytical and defense systems. High-quality silicon wafer without damages is essential for these applications. laser scan process material rapidly and accurately. An ultrafast laser microprocessing has been considered as promising technique to remove material rapidly and accurately. These laser scan significantly reduce the heat-affected zone in the ablated area and then active extremely high accuracy and resolution. This talk will present the recent works concerning ultrafast laser thinning, and grinding silicon wafer. Surface topography, microstructure and residual stress of both as-received surface and laser-machined surface were analyzed carefully by 3D laser scanning confocal microscope (LSCM), X-ray diffraction (XRD), scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS) and Raman microscope. Moreover, electrical properties of laser-machined wafer have been investigated to examine the effect of laser micromachining on Si substrate via characterizations of resistivity and I-V curves. After laser thinning, the wafer thickness has been reduced up to 50%, while the depth of heat affect zone (HAZ) is less than 1 µm, , and compressive stress can be achieved at the laser-machined surface. No obvious damages such as micro-cracks or micro-holes have been observed at the laser-grinded surface. As-received surface defects including SiO2 layer and saw-mark have been significantly reduced, while average surface roughness has been decreased. Besides, laser micromachining causes little influence on electrical properties of wafer. This proof of concept process has the potential application in mass production of integrated circuit industry.

Keywords: Ultrafast laser, Laser processing, Silicon wafer, Surface Modification, Properties

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