| Summary: | 碩士 === 國立東華大學 === 材料科學與工程學系 === 96 === The goal of this study is to tightly control the feature sizes and geometrical shapes of micro-/nanolens arrays, in order to produce precise, spherical micro-/nanolens arrays.
We found that the speed of the thermal reflow of photoresist increases with decreasing the temperature of soft bake, but with increasing the temperature of thermal reflow. Howevere, the diffusion rate of the photoresist molecules along the photoresist/silicon interface increases with increasing the temperature of thermal reflow, which makes the production of precise microlens arrays very difficult.
Therefore, we design a new system for the thermal reflow of photoresist. By using this system, the temperature at the free surface of photoresist (TPR) can be much greater than the temperature at the photoresist/silicon interface (TWafer). In fact, high TPR increases the diffusion rate of photoresist molecules along the free surface, but low TWafer decreases or limits the diffusion of the photoresist molecules along the photoresist/silicon interface. So we can precisely control the feature sizes of thermal-reflowed microlens arrays. By using this concept, we have successfully fabricated spherical microlenses greater than a hemisphere.
We have also successfully converted the photoresist with subwavelength grating microstructures into nano-cylindrical lens arrays with connecting bases by using the same concept and apparatus as that used for microlens arrays.
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