Local anodic bonding of a common Kovar alloy to Pyrex is presented. This technique is ideally suitable for temperature-, solvent- and pressure-resistant microfluidic connections. In this paper we mainly concentrate on the stress problems occurring during and after bonding. Because of the different thermal expansion coefficients of Kovar and Pyrex a structure is added in order to release the thermal stresses induced during bonding. Optimum bonding conditions in vacuum on Pyrex and on a Pyrex-Si bonded wafer pair are investigated. In the latter case bonding for 3 h at 250 °C and 1.5 kV results in a high-quality bond.
Blom, M. T., Chmela, E., Gardeniers, J. G. E., Berenschot, J. W., Elwenspoek, M. C., Tijssen, R., & van den Berg, A. (2001). Local anodic bonding of Kovar to Pyrex aimed at high-pressure, solvent-resistant microfluidic connections. Journal of micromechanics and microengineering, 11(4), 382-385. https://doi.org/10.1088/0960-1317/11/4/317