High-speed bend test method and failure prediction for drop impact reliability

The objective of this study is to obtain experimental failure models governing solder joint failure during drop impact testing of board assemblies. A high-speed bend test was developed to perform displacement-controlled bend test of board assemblies at the high flexing frequencies of drop impact. These test frequencies and amplitudes are not achievable by conventional universal testers. Experimental data was obtained for various PCB strain amplitudes, flexural frequencies solder alloys and pad finishes. Results from the high-speed bend tests are used to construct constant amplitude power law fatigue curves. Solder joint reliability found to be dependent on the test frequency, and therefore strain rate. The experimental failure data from these high-speed bend tests are a required basis for a drop impact failure criterion which can take into account frequency and amplitude effects and which is general enough to be applied to product level testing