Micro processing in glass substrates with pulsed CO2 lasers

While glass is a good candidate material for interposer application, technology for formation of Through-Glass-Vias (TGVs) at high throughput and low cost is required. In this paper, we introduce micro processing technology with high-peak-power pulsed CO₂ lasers which realizes high throughput at low initial and operating cost. Since the wavelength of the CO₂ lasers is 9.3 microns, it is said to be difficult to drill holes with the diameters smaller than 40 microns. With a surface treatment technique of the substrate and fine tuning of the laser conditions, small holes with the diameter of 25 microns can be drilled.