Conductive Adhesive Joints under Combined Load

The work is focused on investigation of resistance changes of conductive adhesive joints under climatic only and under climatic load applied after the mechanical stress. The joints have been formed by assembly of 0R0 SMT resistors of the type 1206 on test boards. Three types of adhesives with epoxy matrix have been tested in three types of climatic load: in heat at the temperature of 125 degrees C, in a relative humidity 95 % and in a combined load heat/humidity at 80 degrees C and 80 % RH. The mechanical stress of the joints has been generated by the indentation of the board with 0R0 components assembled by conductive adhesives for the period of 10 second. It has been found that the change in resistance of the adhesive joints loaded mechanically before the climatic load is greater than the change in resistance of the joints loaded climatically only.