Study on the Copper to Copper Adhesive Joining

초록

Heat-sink for electronic devices has been made with Al and Cu due to their high thermal conductivity which is making difficulty in fusion welding. Brazing and soldering can be used for copper to copper joining. In case of the low heat input required, however, adhesive bonding could be a solution. Copper is known to be difficult to bond satisfactorily, especially if high shear and peel strengths are desired. The prime reason is that the copper oxide develops rapidly and its layer is weakly attached to the base metal under usual conditions. Thus, if clean copper substrate were bonded, the initial strength of the joint would be high, but on environmental exposure an oxide layer could develop which will reduce the durability of the joint. In this study, copper to copper adhesive joining at the relatively low temperature of 150℃ was investigated for the various epoxy adhesive formulations and joint structures. Epoxy adhesive formulations were made with the various curing agents and coupling agents. The thermal and curing behavior of adhesives were investigated using DSC (Differential Scanning Calorimetry), DEA (Dielectric Analysis) and TGA (Thermogravimetric Analysis). The lap shear strength was measured for as-cured and aged specimens to evaluate the durability of joints.