紫外光發光二極體於微影製程的應用

The Application of UV-LEDs on the Photolithography

黃振康(Chen-Kang Huang) ； 宋正綱(Jeng-Gang Sung)

《生物機電工程學報》 2卷2期 (2009/06) Pp. 29-47

摘要

本研究之目的爲利用高功率的紫外光發光二極體於微影製程之中，期望藉由紫外光發光二極體的壽命長及快速點亮等優點，取代目前曝光系統中的汞蒸汽燈。在系統設備上，首先於無塵室中建立接觸式的曝光機台，作爲光源測試之用；其中機台主要包括觀測系統、微調載台及光源模組。將不同數量的紫外光發光二極體安置於散熱鰭片上，分別製作Type1、Type2、Type3三型光源模組；其中Type1光源爲6顆1W的發光二極體，而Type2、Type3分別由7顆與12顆3W的發光二極體所組成。在光源特性的改善上，本研究目前共使用球面反射鏡、拋物面反射杯、透鏡與平行板來增進平行度或光源強度，並將其應用至S1813光阻的製程中，完成後的圖案再進行線寬的量測，最後統計出在不同受光區域中所能完成的最小線徑。統計的結果顯示單顆的光源在使用球面反射鏡時能成功完成20mm的線徑複製；但單顆LED的發光強度低，曝光時間達5分鐘。而拋物面反射杯的使用可減少因爲多光源所造成的複影現象，但無法完全消除；反射杯的使用可將紫外線強度提升6至10倍，並且將視角由原本140o縮小至30o。透鏡的使用雖可消除複影，但卻會因爲光源爲多點光源而產生不正常的光點。在本研究中平行板的使用由於受光面積不均勻，因此出現部分區域的線條斷裂。研究結果顯示UV-LED在線徑100mm以上的應用中可以取代汞蒸汽燈，在微米級需求時需要輔以其他技術與方法以得到較小的線徑。

關鍵字

紫外光發光二極體 ； 平行度 ； 曝光機 ； 微影製程

並列摘要

This study was to utilize UV-LEDs in the photolithography process, and it was expected to take the advantages of UV-LED, such as long life and fast response, to replace mercury vapor lamps used in the industry. In this research, we constructed the contact exposure system in clean room for tests. The system included an observing instrument, an adjustable micro-stage, and a light module. UV-LEDs installed on a heat sink formed a light module. There were three types of light modules tested in this study. Type 1 composed of six 1 Watt LEDs, and Type 2 and 3 held seven and twelve 3 Watt UV-LEDs, respectively. Spherical reflector, parabolic reflectors, lens and collimator were tested to improve the optical characteristics. After S1813 photolithography process, the pattern sizes were measured and concluded the minimum feature size reproducible in every region. The result of single UV-LED with a spherical reflector could print out 20 mm lines on the substrate, but a lower intensity of single UV-LED caused longer exposure time of more than 5 minutes. The parabolic reflectors could relieve multiple images, but this phenomenon resulted from multi-point light source was hard to avoid. However, reflectors could enhance UV intensity about six to ten times, and decreased the angle of view from 140 degree to 30 degree. With lens, the multiple images were almost eliminated, but the defective light spots, resulted from the imperfect light source, occurred. The usage of collimator alleviated multiple images, but some patterns could not be reproduced. In general, the UV-LEDs are able to replace the mercury vapor lamps in application of 100+ mm. For sub-100 micron applications, some techniques or methods must be adopted.

並列關鍵字

UV-LED ； Parallelism ； Exposure system ； Photolithography