Research On Reactive Bonding Technology And Application

Self-propagating High temperature Synthesis (SHS) exothermic reaction bonding has many advantages, such as high bonding efficiency, little heat impact on device, and low bonding cost. It can be used for optoelectronic integration and MEMS packaging. In addition, not only can it be integrated with the usual MEMS packaging manufacturing technology, taking eutectic bonding and solder bonding for example, but also be compatible with semiconductor manufacturing technology. Therefore, packaging by self-propagating exothermic reaction bonding can be researched and industrialised to a standarized MEMS packaging manufacturing technology, for wide application. In this dissertation, our research is based on SHS reaction bonding, focusing on optoelectronic integration and wafer-level local heating pattern packaging. Research methods used in reaction bonding technology include theoretical analysis, numerical simulation and bonding experiments.Firstly, based on heat transfer and mass flow theory of the SHS exothermic reaction, SHS exothermic reaction are characterized. Some characters about SHS exothermic reaction, such as concentration, heat flow, and velocity of reaction are investigated. Moreover, SHS reaction bonding model is established. Based on nonlinearity and full transient thermal analysis method, SHS exothermic reaction bonding can be simulated correctly.Secondly, based on phenomenon of SHS exothermic reaction, the nature of SHS exothermic reaction are studied. With Differential Scanning Calorimetry(DSC), X-Ray diffraction (XRD)/ X-Ray Fluorescence(XRF), the heats of the reactions and the reaction products of these Al/Ni nanometer partical foils are characterized. In DSC curves of SHS reaction, three exothermic peaks were observed and the heat of reaction is integrated to 57.5kJ/mol. After the reaction, all major peaks correspond to the ordered B2 AlNi compound in XRD/XRF traces. The measured values are used as inputs to numerically predict thermal transport during the bonding process.Thirdly, some impacts on the SHS exothermic reaction bonding are investigated, including but not limited to, the pressure applied during joining, the solder used, the solder thickness and the packaging material. The results of the experiments show that as pressure applied during joining increases from 10kPa to 600kPa, bonding tensile strength rises quickly from 2MPa to 6MPa. Further increasing pressure applied, the bonding tensile strength will decrease. Meanwhile, when the solder thickness is 25μm, the bonding tensile strength is better. The kind of the solder used also affects the bonding quality. Finally, optoelectronic materials integration are achieved successfully.Finally, wafer-level hermetically sealed packaging by SHS exothermic reaction localized heating pattern bonding is achieved. A set of semiconductor manufacturing technology used for sealed packaging groove formation on silicon wafer, and succeed in hermetically sealed packaging. With the bonding pressure 600kPa and 58μm thickness PbSn solder, the packaging strength is better and create a hermetic seal. Interface microstructures are observed with SEM, and the results show that the bonding interfaces are perfect.