| Summary: | 碩士 === 國立交通大學 === 照明與能源光電研究所 === 101 === Nowadays, LED solid-state lighting has become widely, therefore high- power LED has become increasingly important. The output efficiency of LED is transferred to optical type about 30%; heat type about 70%.So the heat dissapation is more and more important. In my study, we use the flip-chip LED based on GaN material. And we try to use low temperature eutectic bonding technology to improve the heat dissipation issue effectively. The first part we investigate the low temperature eutectic bonding, we use Sn0.7Cu solder, which melting point is 227℃, Its lower than An20Sn(melting point is 279℃) which we often used. And the price of Sn0.7Cu is lower than An20Sn.But this material has a big difficulty at second package. It is “re-melting”. This issue cause the thermal resistance increased.Further it can decay the LED device life time. So we solve the re-melting issue mainly in my first part to optimize this technology
The second part , we will measure the thermal resistance for re-melting result and improve result. Them we can calculate the LED temperature from junction to die attach region for these two condition. And the result between re-melting and improve result is strongly affect EL spectrum 、relative output power、CIE offset、reliability and so on. Integration all measure result, the improve result optimization greatly for optical and heat characteristic. So in my study ,we have already developed a low temperature and low price technology.
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