Abstract
The laser beam microscopy was applied to the in-situ observation of thermal deformation of the tin-Kovar joint in heating and cooling processes over the temperature range between 298 and 423K. The surface displacement of the tin-Kovar joint was measured with accuracy at 0.1μm, and the crack initiation and propagation of the tin-Kovar joint was observed in-situ during the heating and cooling the joint. Using the axial symmetric 2-dimensional thermo-elasto-plastic analysis, the stress-strain distributions were calculated in the heating and cooling processes over the temperature range between 298 and 423K. The observed displacement and calculated one agreed in the heating process, whereas the calculated displacement differed from the observed one in the cooling process. The calculated displacement accumulated in the thermal cycle, not returning to the initial position, and the correlation between the observed displacement and calculated one in heating and cooling processes was discussed.
