LDMOS热阻的电学法测试与分析

Electrical Test and Analysis on Thermal Resistance of LDMOS

基于结构函数理论,运用电学测试法,提取封装LDMOS导热路径上各层材料的热阻值,以及管壳与恒温平台之间的接触热阻值。对各层热阻进行分析,发现焊料层的热阻远大于理论值,提出了一种减小焊料层热阻的方法。改变管壳与恒温平台的接触情况,分别测出不同接触情况下的热阻值,对比发现接触情况会影响结到壳热阻的大小,提出了减小接触热阻的方法。

Based on the structure function theory , thermal resistances of all layers of materials in the heat flow path in LDMOS as well as the contact thermal resistances between the case and the constant temperature platform had been tested by using electrical test method. The thermal resistances of all layers had been analyzed, and it was found that the thermal resistance of solder was much greater than its theoretical value, then a method of how to reduce the thermal resistance of solder was proposed. The thermal resistances tested under different contact situations were compared, so it was found that different contacts had different influences on the junction to case thermal resistances, and the methods to reduce the contact thermal resistance were proposed.