一般在製作發光二極體時，為了要增加發光二極體之光萃取效率或是調整發光二極體之遠場光形，常見的方式為在P-GaN或透明導電膜上製作微結構，但其方法有電性不佳或結構製作不易之缺點，因此要同時兼顧電性與光性一直是大家努力的目標。 本篇論文最主要的目的是將微結構製作於打線封裝的發光二極體晶片表面，並藉此來改善發光二極體之發光效率、遠場光形修正及電特性不佳的問題。由於並未對發光二極體本身進行各式蝕刻製程，因此經過壓印製程之後順向電壓依舊維持於3.4V，足可證明電特性並未因此而受到影響。但是在出光表現上，因為旋轉玻璃基材(Spin on Glass , SOG)之折射率介於空氣與氮化鎵之間，漸變折射率對於提升晶片的光萃取效率有直接的影響，而壓印所製作的微結構，可有效的提昇晶片的光萃取效率，依據所製作的2D圓柱、金字塔及1D的光柵結構而產生39.1%、35.3%及19.8%的光強度提升。在遠場光型調制方面，光形也從原本的朗柏遜分佈變成非對稱的遠場光形分佈，配合後端的光學設計，可使發光二極體應用更加多樣化。除此之外，SOG經過高溫處理之後，特性近似二氧化矽，具備化學及物理的穩定性，可提供發光二極體晶片一定程度的封裝保護。經本論文討探後，利用壓印方式所製作之發光二極體對於兼顧電性與光性是可以達成的。In this study, micro-structures were fabricated on wire bonding LED. Light extraction efficiency enhancement and far field pattern modulation can be achieved by such micro-structures. Different to traditional surface roughness and chip shaping, we use embossing technique to make micro-structures. Embossing technique possesses large area, high yield, and low fabrication cost. Most important of all the method will not damage the electrical performance of LED. The index of imprinting material, SOG, is 1.4 which is smaller than transparent conduction layer and air, so that the transmission decay due to index difference can be reduced. Besides, the property of SOG is similar to SiO2 such property can be used as a package material. The forward voltage of our LED after embossing processing can be maintained at 3.4V at 20mA. However, the light extraction efficiency performances dependent different 2D cylinder, pyramid and 1D grating which can raise 39.1%, 35.3% and 19.8%. The far field pattern is also changed from Lambertian light source to an asymmetric one. In the future, we will use such performance to work with the other optical design and increase the application of LED.
