Journal of Advanced Research (May 2021)

Study on machining characteristics of magnetically controlled laser induced plasma micro-machining single-crystal silicon

  • Yanming Zhang,
  • Zhen Zhang,
  • Yi Zhang,
  • Denghua Liu,
  • Jie Wu,
  • Yu Huang,
  • Guojun Zhang

Journal volume & issue
Vol. 30
pp. 39 – 51

Abstract

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Introduction: Laser induced plasma micro-machining (LIPMM) has proved its superiority in micro-machining of hard and brittle materials due to less thermal defects, smaller heat affected zone and larger aspect ratio compared to conventional laser ablation. Objectives: In order to improve characteristics and stability of induced plasma, this paper proposed magnetically controlled LIPMM (MC-LIPMM) to achieve a good performance of processing single-crystal silicon which is widely used in solid state electronics and infrared optical applications. Methods: A comprehensive study on surface integrity and geometrical shape was conducted based on the experimental method. Firstly, the mechanism of MC-LIPMM including laser-plasma, laser-materials interactions and transport effects was theoretically analyzed. Then a series of experiments was conducted to completely investigate the effect of magnetic field intensity, pulse repetition frequency, and bubble behavior on surface integrity and geometrical shape of micro channels. Results: It revealed that magnetic field contributed to maximum reduction of 12.64% for heat affected zone and 62.57% for width while maximum increase of 26.23% for depth and 90.26% for aspect ratio. Conclusion: This research confirms that MC-LIPMM can improve the machining characteristics of silicon materials and cavitation bubbles shows an apparently negative impact on the surface morphology.

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