TGV through-hole double-sided electroplated copper filling mode regulation and process reliability test study

The solid filling of through-glass via (TGV) through-hole part through double-sided electroplating copper has the advantages of high TGV through-hole density, large TGV thickness and size range, high thermodynamic reliability, wafer-level/board-level process, and simple process flow, and is a potential preferred metallization route for TGV interposer boards in advanced packaging applications such as “core” 2.5D/3D integration and photoelectric co-packaging (co-packaged-optics, CPO). This paper introduced the regulation of the copper layer on the copper layer in the process of double-sided electroplating copper filling TGV through-hole design based on the domestic electroplating chemical system and the design of the research group, and realized the copper-plating copper-metallization method of X-type and “bridge-type” straight-through hole TGV holes. According to the JEDEC standard test, the reliability performance of the TGV through-hole glass–Ti–Cu metallization system in the highly accelerated stress test (HAST), temperature cycle test (TCT), high-temperature storage (HTS) and other aspects was studied. The advantages of TGV partial solid filling metallization process were verified, and it was found that the vacuum leakage rate and DC resistance of TGV copper interconnection were the most sensitive to the HAST test, while the microdefects and penetrating cracks of the Ti–Cu interface were the main failure modes of TGV copper interconnection in the HAST test, revealing that Ti tends to diffuse to the glass substrate and Cu tends to diffuse to the Ti layer in the TGV copper interconnect Cu–Ti–glass material system, resulting in defects at the Ti–Cu interface. The crack is the main mechanism of microcrack formation, which provides guidance and suggestions for the selection and design of metallized material system. The wafer-level packaging TGV cap disc for bulk-silicon RF MEMS devices, RF-integrated large-area TGV adapter board samples, TGV adapter board stacking-integrated millimeter wave antennas were displayed, demonstrating the feasibility of wafer-level process application and making technical reserves for subsequent integration applications.