Geometry Optimization of Nonideal Through-Glass Vias (TGVs) for Enhanced Electrical and Mechanical Performance

Through-glass vias (TGVs) have attracted considerable attention in advanced packaging because they offer low dielectric loss and good electrical insulation. However, the tapered sidewalls formed during fabrication can affect the reliability of glass-based packages. These sidewalls increase the parasitic inductance at high frequencies and cause nonuniform stress under thermal loading. Existing TGV inductance models still have limited ability to describe skin-current effects in nonvertical vias. This study presents an analytical model for tapered TGVs that includes skin current and defines the frequency range in which the model is applicable. The effect of taper angle on stress distribution at 200 °C is also examined. The results show that the taper angle redistributes stress in the copper column and reduces stress concentration at the Cu/glass interface. By further optimizing laser power, ultrasonic power, HF concentration, etching temperature, and ammonium fluoride concentration, precise control of the TGV taper is achieved. This work provides a design reference and an optimization strategy for high-performance glass interposers.