用激光测量高热可靠性电子器件的热变形

本文提出了一种测量大功率电子器件热变形的双曙光激光全息干涉法,针对一种可靠性要求很高的电子器件-火箭点火用固态继电器进行实际测试,试验结果表明,固态继电器在大负载功率工作状态时,芯片表面的干涉条纹较多,条纹弯曲程度较大,因此反映了芯片热变形和热应力增大趋势较为明显。

Test of Thermal Deformation for Electronic Devices of High Thermal Reliability

Thermal deformation can be caused by high partial heat flux and greatly reduce thermal reliability of electronic devices.In this paper, an attempt is made to measure the thermal deformation of high power electronic devices under working condition using laser holographic interferometry with double exposure.Laser holographic interferometry is an untouched measurement with measurement precision up to micron dimension.The electronic device chosen for measurement is a type of solid state relay which is used for ignition of rockets.The output circuit of the solid state relay is made up of a MOSFET chip and the power density of the chip can reach high value.In particular situations thermal deformation and stress may significantly influence working performance of the solid state relay.The bulk deformation of the chip and its mount is estimated by number of interferential stripes on chip surface.While thermal stress and deformation can be estimated by curvature of interferential stripes on chip surface. Experimental results indicate that there are more interferential stripes on chip surface and greater flexural degree of stripes under high power. Therefore, these results reflect large out of plain displacement and deformed size of the chip with the increase of load current.