波長10.6 μm的二氧化碳雷射具有低成本、快速與彈性製造優勢，可應用於高分子材料、玻璃與陶瓷相關的硬脆材料加工。二氧化碳雷射系統亦廣泛被應用在微通道消融、切割、微細鑽孔加工、材料退火製程，並可使用於微機電、生物晶片、光學元件、顯示面板與牙科雷射應用。二氧化碳雷射主要憑藉著光熱效應達到材料移除效果，雷射直接加工所產生的噴濺、凸塊、微裂痕與燒焦等材料缺陷將會影響到微結構後續相關應用面。本研究提出幾項具有優勢的雷射直接加工方式，包含水輔助雷射加工用於消除微裂痕與加工區塊燒焦問題、覆蓋層保護製程用於抑制凸塊形成、提升蝕刻效率與降低特徵尺寸，以及玻璃輔助矽加工以不可加工矽基板的二氧化碳雷射達成高蝕刻效率、深鑽孔與矽基板劈裂行為。
水輔助雷射加工方法可有效降低被加工物表面溫度、熱影響區域、溫度梯度與表面熱應力，經由水的熱傳作用亦可解決破裂與燒焦問題，並利用水的高度穩定性在雷射加工期間的對流作用移除噴濺或累積的再熔融複合物。加工尺度可從空氣中的400–500 μm減少至水輔助的150–200 μm或更小尺度。結合水輔助加工與低溫接合技術可有效應用於自驅動玻璃流體晶片的製作，此晶片可應用於不同黏滯係數的驅動與生物醫學相關的血液測試。覆蓋層保護製程可降低加工尺度與提高蝕刻效率，本研究亦提出高分子保護層與金屬光罩輔助方式針對PMMA與玻璃基板進行微尺度加工。其中，金屬光罩輔助雷射加工製成可有效將加工尺度從空氣條件的234.6 μm降至金屬光罩輔助的50.9 μm。上述加工方式可有效應用於微流道製作且可有效解決直接加工所造成的流道阻塞問題，凸塊高度從直接加工的10.6 μm降低到金屬光罩輔助的0.2 μm，微流道寬度亦可從190.9 μm降低至58.2 μm大小。光罩輔助雷射製程亦可應用於導光板製程，本研究所製作的高分子導光板具有商業化模板程度的75 %出光均齊度與 2165.25 cd/m2有效出光強度。
玻璃輔助二氧化碳雷射加工技術可改變矽的光吸收行為並可針對矽基板進行有效蝕刻，新的加工技術機制將被探討於電子躍升、表面氧化與矽材料在高溫環境下的光吸收性質。溶膠凝膠法製備非晶的二氧化鈦薄膜並備配合雷射退火參數可用於控制二氧化鈦薄膜轉換至銳鈦礦(Anatase)與金紅石(Rutile)結晶相結構，此法具有潛力應用於光催化與光電子相關研究。本研究規劃的雷射退火製程可用於建立與探討微結構形成與二氧化鈦相變化之研究。ANSYS有限元素分析方法亦被使用來建立一簡單熱分析模型，用於探討表面溫度熱傳與熱應力分佈狀態在空氣與上述輔助性雷射加工過程的差異性。其中，雷射退火的熱傳模型亦被建立並有效論證二氧化鈦相變化的溫度條件與分析。

The CO2 laser of 10.6 μm in wavelength is an inexpensive, rapid and flexible one for the soft polymer and hard glass and ceramic related materials processing. It has been widely applied to the fabrication of microchannel ablation, cutting, microhole drilling, material annealing and modification in the categories of MEMS, bio-chip, optical/optoelectronic devices, displays and laser dentistry. The basic CO2 laser physics is photo-thermal mechanism for material removal therefore some defects of debris, bulges, cracks and scorches around ablated microstructure are formed during laser processing in air which degrades the device yield and quality for bonding. In this dissertation, some advanced laser processing methods have been proposed for improving the microstructure quality of fabrication including Liquid Assisted Laser Processing (LALP), cover-layer protection processing and Glass Assisted CO2 LAser Processing (GACLAP) for eliminating the cracks and scorches defects, diminishing bulges height and reducing feature size, even making the transparent-in-nature silicon material to be etched, drilled and cut.
LALP can effectively reduce the temperature, heat-affected zone, thermal gradient and stress via water for hindering the crack and scorch formation together with the laser heating induced stronger natural convection in water for carrying debris away to reduce bulge height. The feature size can be reduced from 400–500 μm via traditional processing in air to 150–200 μm even smaller via LALP. Combing LALP and low-temperature bonding techniques have been used for the fabrication of capillary-driven glass-based microfluidic chip for the application of low-to-high viscosity fluid actuating and biomedical blood coagulation testing. Cover-layer protection processing is effective in reducing feature size and enhancing etching rate during laser irradiation period, both PDMS protection processing and foil mask assisted processing have been applied to micromachining in PMMA and glass substructure. Especially the foil mask assisted machining can reduce the feature size from 234.6 μm in air to 50.9 μm with foil assisted method. It has effective in microchannel fabrication and eliminate clogging problem during laser direct process, the bulge height also has reduced from 10.6 μm in air to 0.2 μm with foil mask assisted processing and the microchannel width has reduced from 190.9 μm to 58.2 μm. It also apply to light guide plate application and the light uniformity and average luminance of microdots structure reaches 75 % and 2165.25 cd/m2, which meet the requirements of commercial light guide plate.
GACLAP can change light absorption behavior of Si and make Si be etched from the top surface toward the interface whose new mechanism is discussed in viewpoint of the variation of electronic band structure, surface oxidation and light absorption of Si at high temperature. Also, a simple CO2 laser annealing process for titanium dioxide treatment has also been developed instead of conventional expensive short wavelength laser annealing and non-selective high-temperature furnace annealing. Both crystalline rutile and anatase titanium dioxide transformation from amorphous titanium oxide can be controlled by the sol-gel composition and laser annealing parameters for material property adjustment which is potentially used for the photocatalyst and optoelectronic application. The relationship between process, microstructure and phase transformation of titanium oxide is discussed and established. A simple thermal model and ANSYS software are adopted for the analysis of thermal and stress distribution on specimen during the laser irradiation in air and above assisted processing.

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