There is a growing demand for precision zero-taper holes in glass and similar materials. The performance characteristics of AdValue Photonics' (Tucson, AZ) fiber lasers have enabled high-speed zero-taper hole drilling in transparent glass materials with chip sizes below 20 µm, providing a cost-effective solution previously thought impossible.

Conventional laser hole drilling processes typically result in tapered holes. Complex 5-axis beam steering systems are required to minimize taper by adjusting the entrance angle of the laser beam dynamically in sync with the trepanning motion. These systems are expensive, and difficult to align and maintain. In transparent materials, zero-taper holes can be achieved with conventional galvo scan heads. Traditionally, green diode-pumped solid-state (DPSS) lasers with pulse durations of tens of nanoseconds have been used for this process, resulting in chip sizes above 120 µm.

An example of laser-drilled borosilicate glass.

Chip sizes <20 µm require picosecond lasers, while the zero-taper requirement calls for the same process originally developed for green DPSS lasers. AdValue adopted its EVERESTpico 1 µm laser, which features 50 ps pulse duration and 50 µJ pulse energy at 1 MHz repetition rates and M²= 1.3, to the zero-taper hole drilling process to routinely achieve zero-taper holes with chip sizes of <20 µm at high speed in glass and sapphire.