Process simulation of Kovar-glass-silicon bonding for micromachined combustor

High-temperature and high-pressure connection between micro combustor and macro world for feeding of air/fuel gas is required in PowerMEMS development. A Kovar tubing-Glass-Si sealing process has been developed for an on-going PowerMEMS project to connect Kovar tubes with diameters of 2mm and 4mm, to top Si wafer of micro combustor fabricated by DRIE process. Due to the different CTEs (coefficients of thermal expansion) of the connected materials, thermal stress around the sealing area could probably influence the obturation and other properties of the sealed combustor. A numeric simulation on sealing of the structure was conducted on ANSYS software to investigate this kind of sealing process. The thermal stress and displacement from room temperature to combustion circumstance, and to sealing condition as high as 1220K were simulated. The size affection of glass bonder and the metal tubes was investigated. A process of high temperature sealing Kovar-glass-silicon was developed and a prototype of the packaged micro combustor was manufactured.