Biaxial bending strength of TGV glass substrates in ring-on-ring tests: Stress analysis and experimental investigation

Glass substrates and glass interposers are emerging as promising alternatives to organic substrates and silicon interposers in advanced IC packaging for AI, HPC, and 5G/6G applications. This is due to their tunable CTE, high stiffness, excellent electrical performance, low cost, scalability, and compatibility with fine-line RDLs. However, the intrinsic brittleness and crack susceptibility of glass materials constitute major obstacles to their widespread adoption. This study will investigate the mechanics of the through-glass-via (TGV) array in the biaxial bending ring-on-ring (RoR) test using theoretical and numerical stress analyses, and then experimentally determine the bending strength of TGV glass substrates with and without the etching process. The experimentally obtained bending strengths are analyzed and discussed in relation to the corresponding failure modes and underlying mechanical behavior.