- 學位論文
氣體輔助軟模轉印技術開發與應用
Development and Application of Gas-Assisted Transfer Stamping Technique
摘要
本論文以開發氣體輔助軟模轉印技術為主軸，研究以快速簡單的製程技術製作微結構。此製程主要特色有：一.製程單純；二.所製作的微結構無殘留層，不須額外去除殘留層步驟，有效降低製程複雜性，並提高可應用材料之多樣性；三.可製作多層微結構；四.製程相容性高，只要是可溶液製程(solution-processable)之材料皆可進行轉印；五.無須額外化學方法即可進行轉印。 本論文主要研究內容包括黃光微影製程製作底部平整之微結構母模、PDMS鑄造技術製作彈性軟模具、利用有限元素法進行軟模變形模擬分析、單層與雙層微結構轉印製程之開發與微結構轉印製程之應用等部分。 在底部平整之微結構母模製作方面，本研究以電感耦合電漿蝕刻法、乾膜光阻定義圖案與SU-8厚膜光阻定義圖案製作微結構圖案母模，並探討三種方式之優缺點。在軟模變形模擬分析部分，利用光學顯微鏡觀察PDMS軟模實際受力變形的狀態，證明利用有限元素法分析軟模變形狀態之可行性。根據模擬結果，垂直方向壓力會致使PDMS模具微結構間間隙產生垂直方向的位移，可能導致轉印殘留層的產生。模擬結果更提出藉著改變PDMS模具厚度可以有效降低間隙垂直位移量，防止殘留層產生。 在單層與雙層微結構轉印製程之開發方面，提出表面能控制機制，以獲得成功之轉印結果。針對PDMS模具進行氧氣電漿表面處理，藉此提高PDMS模具表面能，使墨水能均勻塗佈於PDMS模具表面，再以加熱方式恢復PDMS模具原有之低表面能特性，同時藉著提高基材溫度增加基材表面能，搭配適當之製程參數，EPG 510光阻墨水可完整轉印至壓克力基材上，且無殘留層產生，並證實微結構轉印製程可將EPG 510光阻轉印於不同基材上(包括PMMA、鋁、不鏽鋼、PET、PC、矽晶片與ITO)。在轉印製程之應用方面，本研究驗證轉印導電高分子材料(PEDOT:PSS)於PMMA基材上，直接製作出有機薄膜電晶體之源極/汲極結構。另外本研究也驗證轉印製程可直接轉印光阻於ITO薄膜與鋁基材上，作為蝕刻擋罩與無電鍍鎳擋罩，而不需經過黃光微影製程。
並列摘要
The thesis develops a micro transfer stamping technique to fabricate microstructures. There are five advantages of the micro transfer stamping technique: 1. This is a simple process; 2. There is no residual layer, therefore no additional process is needed to remove the residual layer; 3. The process can fabricate multi-layer structure; 4. The process is theoretically suitable for all solution-processable materials; 5. No additional chemical process is needed in the process. There are five research topics in this thesis, including fabrication of mold with flat bottom surface using lithography process, casting technique for fabricating PDMS mold, deformation simulation of PDMS mold in the transfer stamping process, development of single-/ multi- layer transfer stamping process, and application of the micro transfer stamping process. In the section of fabrication of mold with flat bottom surface using lithography process, for obtaining the mold with flat bottom surface, ICP, dry film resist and SU-8 were used to fabricate the master mold with microstructures, and compared advantages and disadvantages in this study. In the “deformation simulation of soft mold in the transfer stamping process” section, to verify the accuracy of Infinite Element simulation, we observed the real deformation of PDMS mold using optic microscopy. According to the simulation results, the “gap” between microstructures of PDMS mold sags as the applied pressure is high enough or the gap length is large. A large sagging distance would lead to residual layer appearance in the transfer stamping process. It was found that increasing PDMS mold thickness could prevent residual layer forming. In the section of development of single-/ multi-layer transfer stamping process, we proposed a method of controlling the surface energy to transfer stamping. PDMS mold was treated by oxygen plasma surface treatment to increase the surface energy for uniformly spin coating “ink” on PDMS mold. And then, with proper pressure, temperature, and heating the PDMS mold to restore surface energy for detaching, the ink (EPG510) could successfully be transferred on the PMMA substrate with no residual layer. The section also proves that the micro transfer stamping technique can transfer the ink (EPG510) on various substrate, such as PMMA, aluminum, PET, PC, silicon wafer and ITO. In the section of application of micro transfer stamping technique, we proved that the micro transfer stamping can successfully transfer PEDOT:PSS on PMMA. We also proved that the single-layer transferred PR patterns can replace lithography process, to be directly used as the etching mask or electroless nickel plating mask.