以滲透法及雙面部分曝光製作封閉型微流道

Abstract

本實驗室之前提出一個使用SU-8負型光阻製作封閉型微流道的新製程，僅需要單層光阻塗佈結合雙面部分曝光即可完成，而且流道內部截面可具有高低差結構。但是在進行正向和背向曝分曝光時會有疊加作用，且封閉型微流道在顯影上不易貫穿流道，使的流道高度無法製作在預設的100μm，且流道長度無法突破400μm。 Yoshikazu Hirai的論文中提到，SU-8負型光阻在受到不同的曝後烤溫度 下，其交鍊反應(Cross-Linked)會影響顯影滲透的效率，並提出在曝後烤溫度為85℃時，Cross-Linked下的滲透效率最高，可以有效的提升流道顯影長度及效率。本論文利用雙面部分曝光結合滲透法來進行微流道的製作，不僅可以有效的將具有高低差結構的微流道製作出來，還可將流道長度拉長，並將低流道高度。 經由實驗測試，驗證曝後烤溫度及時間對Cross-Linked的影響，並在曝後 烤溫度為85℃、曝後烤時間15分鐘下，進行單面正向曝光流道長度測試，實驗結果顯示，結合滲透法，可以有效的提升流道長度，將單面流道長度由原本的200μm拉長到2000μm，流道高度也可以在100μm下製作出來。另外也進行曝光疊加的測試，在總劑量若為30mJ 2次曝光與單次曝光相比，厚度會增加約8%。根據上述結果，可以調整在製作微流道的曝光參數，避免曝光過量，本研究最後結合滲透法並找出可行的正向及背向部分曝光劑量參數組合，成功的製作出內部截面具有上下高低差的微流道結構，並拉長流道長度以及降低流道高度。

A novel process was proposed to fabricate sealed micro channels by using negative photoresist SU-8, preciously in our lab, which needs only single-layer coating of and double-side partial exposure to have non-uniform inside cross section. However SU-8 cross-linked effect from double-side exposure mede it difficult to have channels height less than the 100μm, and channels length longer than 400μm length. According to Yoshikazu Hirai’s paper, different post-exposure bake (PEB) temperature, SU-8 will affect the cross-linked effect as well as permeability , so-called semi-cross-linked, when PEB temperature at 85℃ was suggested to increase channel length. Here by combine semi-cross-linked and double-side partial exposure method on SU-8, a fabricate scheme is proposed to fabricate sealed micro channels having non-uniform inside cross section at long channel length and thinness channel height. From experiment results, it is shown that the micro channels length can be increased from 200μm to 2000μm, for the channels height can be reduced from 400μm to 100μm by the process method. Ot is alse found that 10mJ only to single exposure of SU-8 on one side, double exposure will increase the thickness of developed SU-8 about 8%, even at the same total dosage of 30mJ. Finally, a feasible recipe is established to successfully fabricate sealed micro channels with variable inside cross section, and longer channels length and thiness channels height.