Strength determination of high-power LED die using point-load and line-load tests

► Strengths of LED die are tested by point-load test (PLT) and line-load test (LLT). ► Mechanism has been discussed and validated via these test results and analyses. ► Die strengths on chip surface failure are 1.48 GPa for PLT and 1.2 GPa for LLT. ► Die strengths on sapphire surface failure are 1.36 GPa for PLT and 0.64 GPa for LLT. ► Two tests have been found feasible, easy-to-use and reliable for LED die strength.