近場相位移接觸式彈性光罩微影術製作高頻表面聲波元件

FABRICATION OF HIGH-FREQUENCY SURFACE ACOUSTIC WAVE TRANSDUCERS USINGNEAR-FIELD PHASE SHIFT CONTACT-MODE PHOTOLITHOGRAPHY WITH AN ELASTOMERIC PHASE MASK

黃浩閔(Hao-Min Huang)

指導教授 ： 陳克紹

大同大學/工程學院/材料工程學系所/碩士(2005年)

摘要

摘要

由於光學微影技術有其物理上之限制，以及設備昂貴等問題，使得光學微影技術的發展困難，本研究研發製作大尺寸微米或次微米線路之方法如近場相位移微影術NFPSL (near-field phase shift photolithography)，以及使用聚二甲基矽氧烷( polydimethyliloxane, PDMS)之翻印技術，並使用所發展之技術來製作表面聲波（SAW: Surface Acoustic Wave）元件。近場光微影術為利用一機械性質柔軟的相位偏移光罩(通常為PDMS光罩)與光阻做接觸式的曝光，與傳統微影技術不同，其利用近場光在相位光罩之相位反轉邊緣進行曝光(The phase-edge method)，如此一來可獲得遠小於入射光波長線寬之圖型，本研究以曝光波長365nm光源，製作奈米線寬之表面聲波（SAW: Surface Acoustic Wave）元件。使用近場光微影術與其他相位光罩技術做比較有以下優點:(1)製程簡單而且便宜。(2)可利用線寬為微米級之光罩來製作奈米級線寬之圖型。(3) PDMS光罩為一軟性材料，可與曝光表面做完美之接觸。

關鍵字

近場相位移微影技術 ； 表面聲波元件 ； 聚二甲基矽氧烷

並列摘要

Abstract

Surface-acoustic wave (SAW) filters operating at frequency in the 1 to 3 GHz-range have been widely used in the applications of mobile, wireless, cable modem, cellular phone and remote control. Current lithography techniques are feasible for SAW device fabrication, such as I-line (365nm) UV photolithography, imprint lithography, conformal contact photolithography and near field phase shift photolithography (NFPSL). In common production, the narrowest line width must be around 0.3 mm with the I-line UV photolithography typically used in the industry; this corresponds to a quarter-wavelength, giving a maximum frequency of typically 3 GHz. Therefore, lithography with the ability of high-volume-production over large area for producing high frequency (i.e. 1~3 GHz), low-cost SAW devices is anticipated. The operating frequency is limited by fabrication techniques. In order to operate at high frequency, SAW filters can be efficiently excited at higher harmonics of their fundamental frequency. And in NFPSL, a transparent mask induces abrupt changes of the phase of the light used for exposure, and causes optical attenuation, which is owing to destructive optical interference at the edges of circuit features, at those locations. NFPSL is a low-cost, high-throughput production over large areas method for nano-structure pattern transfer and can be used to fabricate nano-structure pattern by using a mask with micro line width pattern. To meet the demands have low-cost and high-volume-production over large area, near field phase shift photolithography may be a better solution than other lithography.
In this study, we demonstrate the high frequency (i.e. 1~3 GHz) and low-cost SAW devices that are fabricated by using the near field phase shift photolithography, as the line widths of NFPSL finger pattern are 10 and 5 um. The mask, which is duplicated from the special design mold with 10 and 5 um line width finger patterns, of the near field phase shift optical lithography has a potential use in SAW devices operating over the gigahertz range.

並列關鍵字

Near field phase shift lithography ； Polydimethylsiloxane ； Surface Acoustic Wave

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