Study on the Through-Glass-Via Formation by Photo-Chemical Etching for 3D IC Application

• Main Authors: Jui-Po Sun, 孫瑞伯
• Other Authors: Zingway Pei
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/28202807730989381014

碩士 === 國立中興大學 === 光電工程研究所 === 100 === Integration of IC chips vertically, named 3-D integration, is an important technology direction to increase packing density, reduce route for signal propagation and hence increase the functionality and clock rate. Current technologies use through-silicon-via to achieve 3-D integration. The high cost of Si, processing and the poor electrical isolation are main problems restricting the realization of 3-D technology. With the use of through-glass-via (TGV) could potentially solve those problems. Besides, optical transparent and chemical-resistant of glass enable the possibility of 3-D ICs having optical modulation and chemical sensing function. However, formation of through-glass-via by dry etching needs high-cost equipment at a long etching time. Drill holes by high energy laser looks a suitable method. The formation of micro-cracks at the surface of glass via and along with via by the laser will cause the electrical fail that limit the application of TGV. In this work, we utilize a photo-chemical etching (PCE) method to form through-glass-via. The PCE is a low cost, damage-free and potentially large-area method for TGV formation. An ultra-violet (355 nm) pulse laser was used to illuminate the glass surface. The illuminated region will crystallize after thermal annealing in a furnace. The crystalized glass shows much faster etching rate than the amorphous region in HF solution. For a relatively thick (600 nm) glass, a via-hole with diameter of around 50μm was demonstrated in laser energy of 6J/cm2. In comparison, at least 120 J/cm2 was required to drill a glass directly. In addition, a 40 selectivity was achieved to the crystallized and amorphous region.