Cost Effective Production of Glass Interposers for 3D ICs Using APEX(TM) Glass Ceramic

Abstract

The most singular focus of the electronics industry during the last 50 years has been to miniaturize ICs by miniaturization of transistors and on-chip interconnections. Two major problems are foreseen with this approach; electrical leakage and lack of improved electrical performance beyond 16nm. As a result, industry is transitioning from the current SOC-based approach to a through-silicon-via (TSV) based 3D IC-stacked approach. However, a major challenge remains; these 3D ICs need to be interconnected to other ICs with a much higher number of I/Os than are available with current ceramic or organic interposers. While silicon interposers currently in development can provide these high I/Os, they cannot do so at low enough cost. In this talk, we will present on our efforts in glass interposers fabrication. Glass interposers possess many advantages over silicon interposers including: cost, production time, and scale. Life MicroFab's APEX™ Glass ceramic is a photo-sensitive material used to create high density arrays of through glass vias (TGVs) using three simple processing steps: exposure, baking, and etching. To date, we have been successful in producing large arrays of 12 micron diameter TGVs, with 14 micron center-to-center pitchs, in 125 micron thick APEX™ Glass ceramic. We will present (1) on our efforts producing high aspect ratio TGVs in thin (500-250 micron) and ultra thin (250-75 micron) APEX™ Glass ceramic wafers, (2) maximum TGV aspect ratios, and (3) TGV fidelity and limits of manufacturing.