| Low-temperature direct bonding has been widely used in the fabrication of silicon-on-insulator (SOI) and micro-electro-mechanical-systems (MEMS) devices packaging in terms of its low temperature, good bonding quality and fewer restriction on bonding materials. Based on the past research of low-temperature silicon direct bonding, this thesis introduced UV exposure into silicon direct bonding, performed investigation on the experiment of low-temperature silicon direct bonding, discussed the mechanism of UV activation on the silicon surface, and researched the bonding quality and bonding reliability in many aspects. The main content of this thesis comprises:1. Researched the property of UV light and its physical and chemical function in cleaning and activation, and discussed the mechanism of short wave UV cleaning and activation, to provide theoretical foundation for the investigation on silicon direct bonding process;2. Investigated the influence of different UV exposure time on the quality of silicon surface and silicon-silicon direct bonding strength from the roughness and bear ratio. Results showed that with a probable time of UV activation, like 3 minutes, the flattest surface and strongest silicon-silicon bonding strength could be attained;3. Researched the influence of annealing temperature and annealing time on bonding strength systematically. Results showed that within a probable annealing temperature, like 350 centigrade, the bonding strength increased as the annealing temperature rised; within a probable annealing time, like 20 hours, the bonding strength increased as the annealing time extended;4. Researched the reliability of UV enhanced low-temperature silicon direct bonding with environmental tests, like high-low temperature cycle, constant temperature and humidity, vibration and shock. Results showed that although the bonding strength decreased a little after undergoing those environmental tests, silicon wafer can still keep high bonding strength and reliability. |
PDF Full Text Request