LED环氧灌封工艺对其可靠性的影响

Impact of LED Epoxy Casting Process on Its Reliability

根据实际工作中分析发光二极管(LED)产品失效问题所获得的经验,探讨环氧树脂灌封工艺对LED可靠性的影响。采用理论结合试验验证的方法,从环氧树脂材料性能、固化工艺条件和改善树脂材料性能等方面,总结出环氧树脂灌封工艺影响LED可靠性的具体因素。环氧树脂材料的性能参数如玻璃化转变温度、热膨胀系数和弹性模量等会影响LED耐焊接热和光衰的能力;降低固化工艺条件会减少LED内应力,防止芯片隐裂;在环氧树脂中添加偶联剂可以提高LED产品气密性,防止水汽渗透,提高LED可靠性。最后建议应当根据不同LED的可靠性要求,选择合适的环氧树脂和固化工艺条件。

According to the experience gained from the analysis of light emitting diode （LED） product failure problems in practical working, the impact of epoxy casting process on LED reliability was discussed. With the method of combining theory and experiment, the specific factors of epoxy resin casting process to influence LED reliability were summarized from aspects including material properties of epoxy resin, curing process condition and resin material performance improvement. The epoxy resin material performance parameters such as glass transition temperature, thermal expansion coefficient and elastic modulus will affect LED resistance to soldering heat and light decay; lowering LED curing process conditions will reduce LED inner stress and prevent the chip from hidden cracking; adding coupling agents in epoxy resin can improve the air tightness of LED products, prevent moisture penetration, and improve LED reliability. Finally, the suggestion of choosing appropriate epoxy resin and curing process conditions according to different LED reliability requirements was brought up.