2022 Volume 15 Pages E21-013-1-E21-013-7
Non-destructive two- and three-dimensional neutron imaging was conducted for evaluation of small internal structure in the power module with double-sided cupper heat spreaders under thermal fatigue cycles. Although two-dimensional radiography could not visualize small internal structures, three-dimensional laminography was capable of the visualization. As an application, the commercially available power module was measured by neutron laminography before and after thermal fatigue. It was non-destructively found that the power module was free of degradation at least in the size of 100 µm for 1,000 cycles under this fatigue condition.