銅基板之切割-運用在高功率發光二極體上的銅基板切割

Abstract

藉著前一系列的計畫，銅基材上的高功率發光二極體已經被我們製作出來，且發表在 APL 期刊，引起國際間之報導(附件一)。研究中利用氧化銦錫（ITO）當作擴散阻礙層 將磷化鋁銦鎵發光二極體晶圓接合在銅基材上。被接合在銅基材上的發光二極體元 件，能夠在更高的順向注入電流下操作。而此發光二極體的發光強度比一般砷化鎵基 材發光二極體高出約三倍之多。這顯著改善的原因是因為金屬銅基材具有較高的熱傳 導率。可惜的是，銅金屬是延展性佳的材料，因此，在整個元件的製做過程中，易造 成發光二極體元件毀壞（尤其是在切割晶粒時），良率不高。為了改善這問題，在這計 畫，我們將藉著不同物質與銅反應，將銅基板改質以利後續的銅切割/分離。其中包括 產生1) 較硬的介金屬化合物（intermetallic compound）,以利刀具（dicing saw）的切割。 2)特定的介金屬化合物（intermetallic compound），其與銅的對特定的蝕刻液,有不同的 蝕刻速度。再藉著蝕刻就可將之分離。所用的發光二極體將包括現今較熱門的氮化鎵 （GaN）系列與砷化鎵（GaAs）系列。這些方法將可提升製造高功率發光二極體之良 率。

High-power light-emitting diodes (LEDs) have been accomplished by packaging technique and making the device with larger area. High-power LEDs fabricated on Cu substrates were investigated in our previous study. The AlGaInP LED structure was bonded to a Cu substrate by using indium-tin-oxide as a diffusion barrier layer. The bonded LED device on Cu substrate could be operated in a much higher injection forward current. The luminous intensity of the Cu-substrate LEDs could achieve higher value than that of GaAs substrate LEDs. The significant improvement might be caused by the Cu substrate which has higher thermal conductivity. However, Cu substrate is a ductile metal plate and easy to deform during the processing. The deformation of the Cu substrate will destroy the LEDs that were bonded on the Cu substrate. To solve this problem, three methods were proposed: a) choose material to react with Cu to form brittle intermetallic compound, which can be cut by dicing saw; b) to form intermetallic compound, which has different etching ratefrom Cu. By using etching method, Cu substrates can be separated. Finally, LEDs will be fabricated on the Cu substrate. We are looking forward to make high-power LEDs and solve the deformation problem in processing.