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大綱
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摘要
由於氟體感測元件應用多元，不論是環境的監控、智慧工廠內部空氣品質的監控實驗室有毒氣體的偵測與居家特殊氣體偵測等，都扮演著重要的
角色。雷射的特殊製程加工與其精準控制，且不需加工治具，剛好與氣體感測元件的製程相互搭配應用。本論文探討雷射製程應用於氣體感測器的可行性。一般金屬氧化物半導體氣體感測元件其加熱電極與感測薄膜電極位於同一張光軍製程，造成加熱線圈位置偏外側，使加熱區域的溫度不均勻。本研究透過異質複合材料的設計，將加熱電極與感測電極分開，再利用雷射於鉬金屬薄膜上進行圖形化的刻畫需求，也透過雷射銑削的方式進行矽晶圓鑽孔，以達到隨氣體感測元件設計的目的。
脈衝雷射與機械劃線工具相比，雷射光束劃線具有速度快、精度高、工具無磨損等優點。透過紫外光雷射搭配雷射參數的調整，可將感測元件表面的鉬金屬完整移除，也可進行圖形化的加工應用。其次探討感測元件上之矽基-玻璃異質複合材料雷射穿孔的可行性，本研究以雷射銑削(milling)加工精準控制穿孔的孔徑大小輿深度將材料熔飽，經由多道次製程來完成垂直穿孔加工。最後再進行鋁金屬充填於孔洞的切削面上，完成異質晶片導通孔的研究。後續可滿足氣體測試共通載具的需求。
石墨烯是極有潛力的感測材料，但靈敏度較低且回復時間長仍需克服。本研究利用混和氧化還原石墨烯及氧化鋅來提升氣體感測響應，並使用紫外光脈衝雷射對其表面進行改質，最終以離焦加工、雷射輸出功率3W、掃描速度
300 mm/sec
的雷射參數為最佳改質條件。經過雷射改質後的試片，對NO2氣體的氣體響應提升約
48%。改質後透過拉曼光譜輿
X光光電子能譜分析，發現其片電阻下降主因是雷射改質移除還原氧化石墨烯製程中所殘留的氧化官能基團，促使材料缺陷減少，導電率因而上升。透過不同
NOz氣體濃度測試雷射改質後的感測材料性能，發現隨著氣體濃度增加，氣體響應也隨之增加。其材料的穩定性與氣體選擇性也在實驗中被驗證，對日後業界之應用有極大的助益。
關鍵宇：氣體感測元件、異質材料、雷射銑削、氧化還原石墨烯、表面改質
Abstract
Due to the diverse applications of gas
sensing components, whether environmentalmonitoring, monitoring of air
quality inside smart factories, detection of toxic gases in
laboratories, and detection of special gases in homes, they all play
an important role. The special process of laser processing and its
precise control are not limited by the processing fixtures, soit can
be used in conjunction with the process of gas sensing components.
This thesis discussesthe feasibility of applying laser processing to
gas sensors. In general, metal oxidesemiconductor gas sensing
elements, the heating electrode and the sensing film electrode
arelocated in the same photomask manufacturing process, which causes
the heating coils to be positioned outside, making the temperature in
the heating area uneven. In this study,through the design of
heterogeneous composite materials, the heating electrodes and the
sensing electrodes are distinguished, and then the laser is used for
patterning on the molybdenum meta thin film, and the silicon wafer is
drilled by laser milling.
Compared with mechanical scribing
tools, pulse laser scribing has the advantages of fastspeed, high
precision, and no tool wear. Through the adjustment of ultraviolet
laser and laserparameters, the molybdenum metal on the surface of the
sensing element can be completely removed, and graphical
processingapplications can also be performed. Secondly, research
onlasers via technology for silicon-glass heterogeneous composite
materials has applied to sensing elements, in addition to the basic
characteristics of lasers. Laser milling is used to precisely control
the size and depth of the perforated hole to ablate the material, and
complete the vertical through a multi-pass process. Finally, the
aluminum metal was completely filled on the cutting surface of the
hole to complete the study of the hetero-chip via hole. The follow-up
can meet the needs of the common carrier for gas testing.
Graphene is a very promising
sensing material, but its low sensitivity and long recovery time still
need to be overcome. In this study, mixed reduced graphene oxide and
zinc oxide were used to improve the gas sensing response, and the
surface was modified by an ultraviolet pulse laser. Finally, the laser
parameters of the defocused processing, laser output power of 3W, and
scanning speed of 300 mm/sec are the best modification conditions, and
will not cause material erosion. Through Raman spectroscopy and X-ray
photoelectron spectroscopy analysis, the main reason for the decrease
in sheet resistance is that the laser modification process removes the
oxidized functional groups remaining in the reduced graphene oxide
during the manufacturing process, which reduces material defects and
increases electrical conductivity. Through different NO2 gas
concentrations, it can be found that as the concentration increases,
the gas response also increases. The stability and gas selectivity of
its materials were also verified in experiments.
Key words: Sensing element,
Heterogeneous materials, Laser milling, Reduced graphene oxide,
Surface modification
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