微機電微帶天線之製作

Microfabrication of Micromachined Microstrip Antennas

指導教授 : 施勝雄、黃榮堂  研究生 : 蘇金練  機電整合研究所 90年


摘要

  本論文的研究主旨以微機電技術製作30GHz之開槽耦合之微帶線饋入天線,此天線可大幅改善微帶天線之窄頻及耦合量等缺點;設計方面以微帶線基本理論將共振頻求出後,再以模擬軟體進行最佳化設計,並藉由調整阻抗匹配,耦合饋入之研究及運用微機電技術之體加工技術蝕刻所須之空氣層深度,以減低上基板之等效介電係數,並提供相關設計之準則。
在製程方面,改良先前金膜與二氧化矽及氮化矽之附著性問題,藉以適當之負偏壓,建立附著性極優之3μm金膜層,此膜層由於藉由剝離(Lift-Off)技術成形,無法加熱使晶格重整,致使薄膜內應力增加,並導致附著性變差,故本製程試驗出之最佳化製程參數,包括厚膜光阻之高度、靶位高度、氬氣流量、射頻功率、負偏壓等參數,可使得膜層具備較厚且附著性優等優點。背面空氣層之蝕刻控制方面利用加熱器之恆溫控制、深度尺之輔助觀察及磁石攪拌降低垂直方向溫度梯度之變化,準確控制蝕刻度及蝕刻面均勻度。
本研究並藉由微機電技術,將製程標準化,建立一套微機電技術之微帶天線可能的標準製作流程,並且完成以微機電技術製作多層結構之開槽耦合微帶線饋入天線(Aperture Coupled Microstrip Feed Patches)。

ABSTRACT

  This research is aimed to manufacture 30GHz Aperture coupled microstrip fed patches antennas with MEMS technology. This antenna could improve the narrow-band and the coupling. In design,we found the resonant frequency by the basic theorem of microstrip line. By using computer aided simulation to get the optimal design , which tuning the impedance, coupled feeding. Applied the bulk micromachining technology, could etch the depth of the air layer which was designed , it can reduce the dielectric constant of substrate. We also provided an useful research tool and helpful for developing new aperture coupling microstrip feed antennas.
In processes , we improved the adhesion between gold and oxide. Using the bias voltage, we could deposit 3μm gold thin film with good quality with silicon wafer. Since this thin film was patterned by lift-off technology, it couldn’t rally the lattice of gold by heating up the wafer, the intrinsic stress can be increased, this phenomenon will lead to the decrease of the adhesion between gold thin film and silicon substrate. So we conduct experiments as regarding many parameters, including the thickness of thick photoresist, the altitude of target from the substrate, argon flow rate, RF power , nagative bias voltage to deposit. The control of back-side air layer, could use the thermostat , the rule of depth for aiding observation and the magnet agitator to reduce the vertical temperature of gradient. Then we could get the accurate air-depth and smooth etched surface.
This research not only will standardize the practicable fabricating procedures of microstrip antennas by MEMS technology but also have be manufactured the aperture coupled microstrip feed patch antennas of multi-layer structure.