Laser drilling of alumina ceramic substrates: A review

Alumina ceramic substrate is an ideal material for the new generation of microelectronic systems and devices, which is widely used in aerospace, 5G communication, high-power semiconductors, and high-power LED lighting, etc. The high-quality micro-hole processing of the alumina ceramic is the basis for system interconnection and device packaging. The existing laser processing methods, such as the single millisecond laser drilling and nanosecond laser drilling, et al., are difficult to achieve high processing efficiency and quality at the same time. So, hybrid laser processing technologies, such as combined pulse laser (CPL) and liquid-assisted laser drilling, have been widely studied. In this review, we detail the current research status of laser drilling theory of alumina ceramic and its development trend. Also, the current status of the drilling research of long-pulsed laser, short-pulsed laser, and ultrafast laser is discussed, and their advantageous points and respective limitations are compared. In addition, the research hotspot of hybrid laser processing technology is highlighted, specifically from the CPL drilling and liquid-assisted laser drilling. Finally, the future key research directions that need to be conducted in the field of laser drilling of alumina ceramic substrates are discussed to further promote the applicability of the laser drilling technology.