可應用於光學微機電系統之新型微致動器開發與整合

Abstract

摘要 在光學系統的應用與整合上，微機電致動器扮演著相當重要的角色。由於對光學品質的要求，在致動器的設計上常常被賦予需要更平坦的鏡面以及能與系統做整合的要求。本論文分別針對結構鏡面平坦度以及高系統整合能力兩項需求分別設計且製作了藍光dvd讀取時使用到的phase shifter及手機相機防手振時所需使用到的image stabilizer兩組元件。在phase shifter的設計製作中,利用TSMC 0.35 CMOS MEMS製程製作surface micomachining 元件,經由後製程保留40 μm厚的質量塊達到鏡面平坦的要求,並經由光罩設計以及HF vapor的後製程製作出high filter factor(95%)之phase shifter元件。元件本身是利用CMOS MEMS製程所完成，相當適合進行元件與後續電路做整合規劃。在image stabilizer部分，利用silicon on glass以及flip chip bonding的技術分別設計出兩款不同的MEMS image stabilizer，其高深寬比結構造就高驅動力與承載能力。由於其高深寬比結構可提供較強的結構剛性,元件能夠與市售的image sensor做封裝整合。其作動規格符合300~500萬畫素之手機相機拍攝時進行防手振補償,再者,利用特殊的封裝技術將image sensor 封裝在懸空的高深寬比微機電結構上並且進行打線作業。設計完成之MEMS image stabilizer僅有500 μm厚相當適合組裝於手機中,進行手機防手振作業。

MEMS actuators play very important rule in recent optical systems. Because of the requests of excellent optical quality and easy packaging function, optical MEMS actuators are usually designed with flatness reflection or diffraction mirrors, high suspended capability, and higher output force. In this dissertation, two kinds of optical devices, phase shifters and image stabilizers, are designed and fabricated and implemented. In the design of MEMS phase shifter, we utilize the TSMC O.35 μm CMOS MEMS foundry process to manufacture the micromirror array. CMOS foundry process offers the probability of easy integration of MEMS devices and circuits. To eliminate the warped phenomenon of micromirror array, a 40 μm reserved proof mass is designed and fabricated by the self-design post process. Furthermore, by the design of hidden net electrode, this device achieves a high fill factor of more than 90% without an additional flip-chip bonding process and is suitable to attach in holographic DVD pickup head for reading application. In the design of image stabilizer, the proposed stabilizers are designed as a two axis decoupling XY stages. By the design of high aspect ratio structure, this device is with large force output, and adequately strong to suspend an image sensor for anti-shaking photographic function. Furthermore, based on the design of the special wire bonding assisted holder, the image sensor can be successfully bonded to the image stabilizer. Additionally, electrical signals of the image sensor can be connected and integrated with the output circuits based on the signal spring design.