共晶錫鉛銲錫之氣密式封裝之技術研究

Abstract

本論文研發光電元件之氣密性封裝，此技術利用熔融共金銲錫凸塊與鉻銅金之金屬冶金反應層來達到氣密封裝的效果，並具有低溫、低成本、自動對準及大批量製造之優點。本研究利用玻璃和矽兩種基材測試三種封裝組合，分別為矽與矽、矽與玻璃、及玻璃與玻璃。此三種組合在製作過程中皆可達到氣密封裝且未產生脫銲現象。此外，因為所使用之接合材料為銲錫，三者實驗結果均顯示自動對準之現象，在缺乏精密對準儀器的情況之下，加熱封裝後的平均對準誤差仍可達到20 mm的水準，大幅修正了加熱前可能大於100mm的手動對準誤差。可見封裝過程中銲錫融化時產生之表面張力會使基材達到某種程度的自動對準效果。於此研究中，氣密式封裝的接和強度介於3MPa 到 10MPa之間，而三種組合中以玻璃與玻璃基材的接合效果最為良好。綜合研究結果顯示，本技術可作為光電工業界之氣密性。

We develop an easy, low cost, and low temperature optoelectrionic hermetic packaging technology utilizing eutectic SnPb solder and Cr/Ni/Cu bonding pad. Bonding characteristic of our design is investigated on three different setups: silicon-silicon, silicon-glass, and glass-glass samples pairs. For all samples, hermeticity can be achieved at 200oC easily. Our design of bonding pads does not show dewetting during or after the reflow process. By utilizing solder materials, we also observed the characteristic of self-alignment. Because the alignment for sample pairs before bonding process is conducted through visual aligning, original misalignment might be more than 100 mm. With the pulling force of surface tension by solder during reflow process, the final misalignment of our samples were able to self-align to obtain a final misalignment of less than 100mm or even less than 20mm. Bonding strength of the three setups ranges from 3 MPa to 10 MPa. Among the three setups, glass-glass sample pairs appear to have the strongest bonding strength. This low temperature and cost effective soldering process have demonstrates its feasibility in optoelectronic packaging.