Theoretical model of glass reflow process for through glass via (TGV) wafer fabrication

Abstract

Through glass via (TGV) substrate plays an important role in wafer-level vacuum packaging of micro-electro-mechanical system (MEMS) devices. For TGV fabrication, glass reflow is the critical step. In this paper, the theoretical formula was derived from the analogy between the fluid equation and the circuit equation, which is able to describe the process of glass reflow. Parameters such as heating time, temperature, width of the gap and surface tension were considered in the theoretical model, which significantly influence the reflow speed. Simulations were also conducted and the results were compatible with the theoretical results. Moreover, both the theoretical formula and simulation results agree with the experimental results in the two types of fabricating process, including wet etching and deep reactive ion etching, showing the feasibility for providing parameters for glass reflow process in the different techniques.