Product Code: ICA13_M401

High Density Through Glass Vias for Advanced Chip Packaging
Authors:
Rainer Paetzel, Coherent Lasersystems Gmbh & Co. Kg; Goettingen Germany
Ralph Delmdahl, Coherent Lasersystems Gmbh & Co. Kg; Goettingen Germany
Rolf Senczuk, Coherent Lasersystems Gmbh & Co. Kg; Goettingen Germany
Jan Brune, Coherent Lasersystems Gmbh & Co. Kg; Goettingen Germany
Presented at ICALEO 2013

Glass is a promising material from which advanced interposers for high density electrical interconnects for 2.5D chip packaging can be produced. The supply of ultra-thin glass wafers with thicknesses of 100 µm and below is cost-comparable relative to polished thin wafers made of silicon. As thin glass is extremely brittle, micromachining to create through glass via is particularly challenging and laser processing using deep UV excimer lasers at a wavelength of 193 nm and ultra-short pulse laser provide a viable solutions.
In this work, the through glass via drilling capabilities of high energy excimer lasers and ultra-short pulse lasers are shown. Smallest diameters down to 10 µm with smallest pitch size can be realized using excimer laser wavelength of 193 nm at high laser fluence. In favor of volume processing economics, large field size mask illumination supports parallel drilling of up to 1,000 through holes in 50 to 100 µm thin glass sheets. In comparison high power ps-laser achieve good hole quality in a sequential drilling process that achieves high throughput independent from the pitch.
Recent laser glass drilling results will be shown and opportunities for industrial mass production upscaling 193 nm excimer laser technologies and ps-laser will be discussed.