对LED的导散热理论进行了研究，推导出了倒装焊LED芯片结温与封装材料热传导系数之间的关系。通过分析倒装焊LED的焊球材料、衬底粘结材料和芯片内部热沉材料对芯片结温的影响，表明衬底粘结材料对LED的结温影响最大，并且封装材料热传导系数的变化率与封装结构的传热厚度成反比，与传热面积成正比。该研究为倒装焊LED封装结构和材料的设计提供了理论支持。

The variations of the junction temperature with the thermal conductivity coefficient of packaging materials are derived by Heat conduction equation and Thermal resistance formula. On this basis, the impacts on the chip junction temperature of the ball materials, substrate bonding materials and heat sink materials of Flip-chip LED are analyzed with the tool of ANSYS finite element, and the conclusions are verified. It is shown that the thickness of the package structure, heat transfer area and thermal conductivity of packaging materials play an important role in LED chip temperature, and the substrate bonding material has the maximum effect on the junction temperature of LED.