Millisecond Laser Oblique Hole Processing of Alumina Ceramics.

Alumina ceramic substrates are ideal materials for next-generation microelectronic systems and devices, widely used in aerospace, 5G communications, and LED lighting. High-quality hole processing is essential for system interconnection and device packaging. Millisecond lasers have emerged as a promising choice for hole processing in alumina ceramic due to their high processing efficiency. However, existing research has rarely explored the mechanisms and processing techniques of millisecond laser oblique hole formation. This study systematically investigates the dynamic evolution of oblique hole processing in alumina ceramic through theoretical simulations, online detection, and process experiments. Through the simulation model, we have established the relationship between material temperature and hole depth. By analyzing the ablation phenomena on the upper and lower surfaces of the ceramic during the transient interaction process between the millisecond laser and the ceramic, the material removal mechanism in this process is elucidated. Additionally, this study examines the millisecond laser oblique hole processing technology by analyzing the influence of various laser parameters on hole formation. It reveals that appropriately increasing the single-pulse energy of millisecond lasers can optimize the material removal rate and hole taper. Ultimately, the formation mechanism of millisecond laser oblique hole processing in alumina ceramics is comprehensively summarized. The results provide theoretical and methodological guidance for high-speed laser drilling of alumina ceramic substrates.