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在铝合金封装外壳中使用陶瓷基板时,由于热膨胀系数差异巨大,易产生较高热应力,甚至导致基板断裂。采用有限元分析与试验相结合的方法研究了如何从结构设计角度降低这类结构中陶瓷基板的热失配应力问题。研究结果表明,陶瓷基板应力是水平方向拘束导致的热应力和附加弯矩引起的弯曲应力叠加后共同作用的结果,且主要是后者作用的结果。结构设计时应遵循降低陶瓷基板/铝合金盒底厚度比的原则。当基板厚度一定时,应选用厚底铝合金封装外壳。当铝合金外壳底厚一定时,降低陶瓷基板厚度,则可靠性更高。
When using ceramic substrates in aluminum alloy package housings, high thermal stress easily occurs due to the large difference in thermal expansion coefficient, and the substrate is even broken. The method of finite element analysis and experiment is used to study how to reduce the thermal mismatch stress of ceramic substrates in such structures from the perspective of structural design. The results show that the ceramic substrate stress is the result of the combined action of the thermal stress due to horizontal restraint and the bending stress superimposed by additional bending moment, and is mainly the result of the latter. Structural design should follow the principle of reducing the thickness ratio of the ceramic substrate / aluminum box bottom. When the substrate thickness is constant, should be used thick aluminum shell package. When the bottom thickness of aluminum alloy shell, reduce the thickness of the ceramic substrate, the reliability is higher.