軟模低壓滾輪式轉印製程的研發與應用

Development and Application of Rolling process based on soft-mold Micro-stamping Mechanism

朱明輝(Ming-Hui Chu)

指導教授 ： 楊申語

國立臺灣大學/工學院/機械工程學研究所/碩士(2006年)

https://doi.org/10.6342/NTU.2006.00477

摘要

隨著光電產業的蓬勃發展，微小光學元件之市場需求日益遽增，其中微透鏡陣列元件在光計算與光電訊號處理方面日益重要。雖然目前已有許多製作微透鏡陣列之製程技術，但皆需昂貴設備，而且產能不高。有鑑於此，本論文致力開發軟模低壓連續性生產製程，以軟模滾輪轉印微結構UV阻劑於基板上，研究主題包括三方面：
首先是開發創新型的微透鏡陣列元件製作技術：以微機電技術製作出微孔洞陣列矽模仁，再利用氣體熱壓技術以適當溫度、壓力迫使融化的塑膠因表面張力的原因在微孔洞模穴中形成近似球狀之微透鏡；並以實驗設計方法研究影響微透鏡陣列熱壓成型的因子效應，建立起微透鏡陣列熱壓參數的線性迴歸分析。
其次是滾輪式微透鏡陣列軟模之製作：將PC微透鏡陣列薄膜包覆在刻溝矽膠滾輪上以形成一空穴，並注入PDMS溶液，待固化成型後直接製作出大面積之微透鏡陣列滾輪模具。本研究證實搭配刻溝之PDMS滾輪可有效降低滾輪施壓時與基板間的骨頭狀接觸，能與基材表面做完美接觸，有效的提升轉印面積，並達到均勻轉印的效果。
最後是滾輪式微透鏡轉印機台之建立：本研究開發一滾輪式微轉印機台，主要組成包括滾輪升降機構、底座平移輸送機構、真空底盤吸附、UV光源模組以及阻劑塗佈機構等五大部分。塗佈方式採用狹縫式塗佈，適度控制滾輪轉速、塗佈間隙與塗佈流量，並控制轉印參數，將滾輪上微結構轉印在PMMA基板上。本研究並探討成型的操作範圍。複製結果經量測證實轉印效果良好，可製作出高品質、均勻度佳的微透鏡陣列，平均表面粗糙度(R )為9.73nm，最小粗糙度(Ra)值為8.23nm。
本研究成功建立微機電製程、氣體微熱壓技術、矽膠(PDMS)鑄造、狹縫式塗佈技術與滾輪式軟模轉印複製之整合技術平台，並建立起系統化及創新性的微透鏡陣列元件的開發模組技術及最佳製造流程，具有低溫、低壓、製程簡易、快速、低成本與高產能等優勢。

關鍵字

微結構氣體熱壓成型 ； 軟模滾輪式微轉印成型 ； 微透鏡陣列 ； 紫外光固化技術

並列摘要

With the rapid stride of electro-optical industry, the needs for minimized optical elements increase. One of them is micro-lens array, which is widely used in electro-optical instruments for optical fiber communication, image sensing, displaying, and medical inspections. They are now made with expensive facility. Therefore, this thesis is devoted to developing a rolling process based on soft-mold micro-stamping mechanism to replicate micro-structure with UV curable material. There are three major steps in the development process.
First, plastic micro-lens array has been fabricated using gas-assisted hot-embossing. In this method, a silica mold with micro-holes array is first fabricated by conventional photolithography and deep ion etching process. PC film is then placed on the top of the mold, and the stack is placed in a closed chamber. By heating above the characteristic temperature of the plastic film, and introducing nitrogen gas into the chamber, the polymer material is partially filled into the circular holes, and a hemispherical surface is formed due to surface tension. In addition, this study also employs factorial design to develop a precision linear regression for predicting of the height of the lens.
Second, a novel technique to produce a soft roller mold has been developed. A PC micro-lens mold is bent around a carved roller to form a shell-shaped cavity, and then PDMS is poured into it. After curing, a roller with micro-lens cavity array is obtained after PC mold is torn off.
Third, a roller stamping facility with UV exposure capacity has been designed, constructed, and tested. The system consists of a UV-lamp, a roller stamp, a movable platform, a slot-coating system and a pneumatic cylinder unit. During rolling operation, the soft roller mold with micro-lens cavity array uniformly coated with a layer of UV curable photopolymer is pressed against a transparent substrate with a slight pressure. At the same time, the photopolymer is cured by UV-irradiation at room temperature. As the platform moving on, micro-lens array pattern can be continuously fabricated. The lens array is of high quality and good uniformity. The root mean square roughness of the micro-lens is 9.73nm, and average surface roughness is 8.23nm.
These results prove the potential of the roller stamping process for rapid fabricating micro-lens array with high productivity and low cost.

並列關鍵字

Gas-assisted hot embossing ； Micro-transfer molding with soft-roller mold ； Micro-lens array ； UV curable technique

參考文獻

方煌盛,”滾輪式微結構轉印製程開發研究”,台灣大學碩士論文,

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