| Wafer bonding technology now is necessary for packaging. Beside applying to packaging, the technology is also used to produce high light light-emitting diode(LED). We usually use sapphire to grow GaN. But GaN is not good at conducting heat which will reduce the LED’S luminous efficiency. To avoid the bad influence of the phenomenon we can transfer the GaN film to silicon substrate which is good conductors of heat. Now wafer bonding is also a core technology in the in the procedure of manufacturing silicon on insulator(SOI) and in the procedure of manufacturing CMOS image sensor (CIS).In this thesis, we successfully achieve low temperature Au-Au wafer bonding. We use self-designed RIE-ICP plasma etching machine to research the influence of the plasma to Au film and how it affects the bonding quality.The main content of this dissertation is summed up as follows:1.We carried out Si-Si wafer bonding experiment in which we use Au as transition layer. The experiment shows that the relationship between bonding quality and the thickness of Au film. Within limit the more thicker the Au film is the better the bonding quality is.2. using the result we gets from the si-si wafer bonding experiment to carry out si-sapphire wafer bonding experiment. The thickness of Au film is1um. Based on plasma surface activation technology, low temperature Au-Au bonding process is studied by means of Ar plasma and O2/Ar+H2plasma. The impact of plasma activation parameters on Au surface topography and chemical states are studied by AFM and XPS, then relation between plasma activation parameters and bonding quality is established. The detection of bonding interface and bonding strength test results tell us that the activation effect with O2/Ar+H2plasma is superior to that with Ar plasma, the maximum average tensile strength of bonding samples under O2/Ar+H2plasma activation reaches up to17MPa. Relation between residue stress of silicon-sapphire bonding pair and bonding parameters is also investigated. |
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