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题名	用于热释电探测器的红外微透镜阵列的设计与制作
作者	王萌佳
学位类别	硕士
答辩日期	2015-05
授予单位	中国科学院大学
导师	鱼卫星
关键词	热释电探测器 红外微透镜阵列 热回流 大F数微透镜 离子束刻蚀
其他题名	The Design and Fabrication of Infrared Microlens Array Used for Pyroelectric Detectors
学位专业	光学
中文摘要	非制冷红外焦平面阵列可用于对红外目标的凝视成像。由于其无需制冷装置，因而重量轻、功耗小、成本低，在军用和民用领域都得到了广泛应用。对于热释电型非制冷红外焦平面阵列而言，像元间的热串扰是制约其性能的重要因素，因而通常需对其像元进行热隔绝。然而，这会降低探测器的填充因子，进而导致光能利用率下降。而将微透镜阵列和探测器集成则可有效解决这一问题，这种方法使用微小透镜单元将入射到整个像元上的红外辐照汇聚到像元中间的光敏区内。总的来说，集成微透镜阵列可显著提高热释电探测器的灵敏度、信噪比等性能。 从上述具体应用出发，本论文研究了红外微透镜阵列的设计和制作。为了得到大F数、高面形精度红外微透镜阵列，本论文对所用的热回流、离子束刻蚀制作工艺进行了重点研究。具体来说，本文主要取得了以下成果： 1.明确了热释电探测器上的具体应用对红外微透镜阵列的设计所提出的要求。 2.针对传统热回流法难以制作大F数微透镜的问题，深入研究了热回流的理、化机理和动态过程。研究发现光刻胶分子热交联和重力是制约传统热回流法获得大F数微透镜的重要因素。在此基础上，提出二次曝光和倒置热回流相结合的方法，该方法可将光刻胶微透镜的F数上限由2.4提高至9.7。此外，还可以通过调节二次曝光的剂量对微透镜的面形进行精确控制。 3.为实现光刻胶微透镜向硅基底的保形转移，研究了离子束刻蚀过程中的面形演化机制以及刻蚀选择比、刻面效应和槽底开沟对图形转移的影响。在此基础上，通过优化离子束刻蚀角度消除了刻面效应和槽底开沟对微透镜图形转移的不利影响。研究发现当离子束以40度角倾斜入射时，可将实际面形和理想球面的最大误差控制在0.27微米以内，并且刻蚀得到的硅微透镜表面光滑、均匀性良好。
英文摘要	Uncooled Infrared Focal Plane Array (UIRFPA) can be used for staring imaging of infrared objects. As cryogenic operation is not requested for UIRFPAs, the overall weight, power consumption and price of the imaging system can be decreased. For this merit, the UIRFPA has found various applications in both civil and military fields. For pyroelectric UIRFPA, the thermal crosstalk between adjacent pixels can hamper the detector performance significantly. Therefore, thermal isolation of the detector pixels is mandatory, which however gives rise to a decreased fill factor of the detector and thus a low energy usage ratio. This can be solved by integrating a microlens array to concentrate the incident irradiation into the active area of each pixel. In general, integrating the detector with a microlens array can improve its performance greatly in terms of responsivity, signal-noise ratio, etc. Based on the above-mentioned application, both the design and fabrication of infrared microlens array are studied in this work. To obtain microlenses with large focal numbers and high quality, the fabrication process, i.e. thermal reflow and ion beam milling, are mainly investigated. The content of this work can be concluded as followings: 1. The favorable parameters of the microlens array for its application in pyroelectric detectors are clarified. 2. To improve the focal number of microlens fabricated by thermal reflow method, the underlying physical and chemical mechanisms of the reflow process were studied. It is found that gravity and thermal crosslinking of the photoresist material are critical factors that limit conventional thermal reflow method to achieve high focal numbers. Based on this, a novel thermal reflow method with an additional flood exposure process and an upside-down reflow configuration is proposed in this work. By this method, the maximum focal number of the fabricated microlenses can be improved from 2.4 to 9.7. Besides, the microlens profile can be tuned precisely by adjusting the flood exposure dosage. 3. To transfer the photoresist microlens to silicon wafer with high fidelity, the profile evolution process during ion beam etching was studied, as well as the impact of etching selectivity, facet effect and trenching effect. By optimizing the incident angle of the ion beam to 40 degree, the detrimental impact of trenching and facet effect can be eliminated. In this case, the profile error of the obtained microlens with respect to an ideal spherical cap can be limited to be less than 0.27 μm. Besides, the obtained microlens array has a high uniformity and surface smoothness.
公开日期	2015-12-24
内容类型	学位论文
源URL	[http://ir.ciomp.ac.cn/handle/181722/48910]
专题	长春光学精密机械与物理研究所_中科院长春光机所知识产出
推荐引用方式 GB/T 7714	王萌佳. 用于热释电探测器的红外微透镜阵列的设计与制作[D]. 中国科学院大学. 2015.

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