Fracture mechanics analysis of the effects of temperature and material mismatch on the Smart-Cut® technology

Annealing temperature is very critical in the Smart-Cut process especially when material mismatch exists. Experiments have shown that high temperature along with thermal mismatch may fail the Smart-Cut process by inducing severe deformation or cracks on the films. The present paper, following our previous investigations on the Smart-Cut process, studies the effects of temperature and material mismatch on wafer splitting in the Smart-Cut technology by using fracture mechanics analysis. The influence of temperature is explored through its effect on the internal pressure inside the defects and thermal stresses whether the donor wafer and the handle wafer are the same materials or not. Our analysis shows that increasing temperature may promote defect growth by increasing the internal pressure, and that thermal stresses arising from temperature change accompanied by material mismatch may inhibit defect growth and lead to growth deviation. In addition, the results indicate that the elastic mismatch of materials plays a significant role in wafer splitting in the Smart-Cut process even when the thermal stresses vanish.