Low-temperature sol–gel intermediate layer wafer bonding

• Published in: Thin solid films 2006-02, Vol.496 (2), p.560-565
• Main Authors: Deng, S.S., Tan, C.M., Wei, J., Yu, W.B., Nai, S.M.L., Xie, H.
• Format: Article
• Language: English
• Subjects: Applied sciences; Cross-disciplinary physics: materials science; rheology; Electronics; Exact sciences and technology; Hydrophilicity; Liquid phase epitaxy; deposition from liquid phases (melts, solutions, and surface layers on liquids); Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Micro- and nanoelectromechanical devices (mems/nems); Physics; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Small composite design; Sol–gel; Wafer bonding
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/j.tsf.2005.08.371

Silicon-to-silicon wafer bonding has been successfully performed using sol–gel intermediate layer, which is deposited by spinning acid-catalyzed tetraethylthosilicate solution on the surfaces of two silicon wafers to be bonded. The bond strength is up to 35 MPa at a bonding temperature of 100 °C, which is near to the fractured strength of bulk silicon. To investigate the effects of the press parameters, Draper–Lin small composite design is used, as it requires the minimum number of runs in the design of experiments. Statistic analysis shows that the bonding temperature is the dominant factor for the bond quality, while the interaction between bonding temperature and concentration is significant on bond strength. The physical mechanisms of the observed significant effects are discussed. The improvement of the wafer bonding using annealed sol–gel intermediate layer is also proposed.