Experimental Study on Femtosecond Laser-Induced Microjet-Assisted Trepan Drilling of Silicon Wafer

• Main Authors: Chen, Pei, Tu, Senyu, Pan, Rui, Li, Shaowei, Qin, Fei
• Format: Conference Proceeding
• Language: English
• Subjects: Bending; Drilling; Energy dissipation; Fabrication; Femtosecond laser trepan drilling; Laser stability; Laser-induced microjet; Micro vias; Silicon; Stability analysis
• ISSN: 2836-9734
• DOI: 10.1109/ICEPT63120.2024.10668587

Femtosecond laser drilling technology has garnered significant interest in electronic packaging due to its precision and non-thermal characteristics. However, challenges like debris redeposition and energy dissipation can decrease the quality of the laser processing. This study employs femtosecond laser-induced microjet-assisted trepan drilling technique for fabricating through-holes in silicon wafers. During the processing, microjets generated by the femtosecond laser to consistently and efficiently clear ablation debris and cavitation bubbles, ensuring superior hole quality. A comparative experimental analysis with processing under identical parameters in air was conducted, demonstrating that the microjet-assisted trepan drilling technique significantly mitigates debris deposition and recast layer formation. It also enhances the roundness and straightness of the holes and boosts the material removal rate of the trepan drilling process. The fracture stability of silicon wafers processed with this technique was validated through three-point bending tests. Consequently, this study achieved the processing of high-quality through-holes on silicon wafers, offering valuable insights for micro-through-hole fabrication in electronic packaging.