Ultrahigh Aspect Ratio Through Glass Vias Perforation Utilizing Selective Laser‐Induced Etching with Nanochannels

Abstract

At present, perforation of high aspect ratio through glass vias (TGVs) is one of the primary factors limiting the development of glass interposers. Herein, it is based on a large number of experiments, combined with mechanistic analysis, to realize the perforation of ultrahigh/high aspect ratio fused silica TGVs using selective laser‐induced etching. First, the effect of the number of pulses as well as other laser parameters on the etching selectivity is systematically investigated. It is found that the formation of nanochannels in fused silica is crucial in determining the high selectivity. Subsequently, a model based on diffusion theory is proposed to mathematically explain the reasons for the high selectivity generation. Finally, the perforations of TGVs with diameters of 5.4–26.4 μm, aspect ratios of 11.7–61.3, and vertical sidewalls are achieved, at a laser treatment speed of ≈10 000 TGVs per minute. This research can serve as an essential reference for the manufacturing of TGVs with high aspect ratios and glass interposers with high interconnection density.