| 题名 | 倾斜/旋转紫外光刻技术研究 |
| 作者 | 何骏 |
| 学位类别 | 硕士 |
| 答辩日期 | 2015 |
| 授予单位 | 中国科学院上海光学精密机械研究所 |
| 导师 | 刘世杰 |
| 关键词 | 倾斜/旋转紫外光刻 仿真模型 MEMS 衍射 掩模优化 |
| 其他题名 | Study on the inclined/rotated UV lithography technique |
| 中文摘要 | 倾斜/旋转紫外光刻技术是近年来发展起来的一种新型紫外光刻方法，该方法通过改进传统紫外光刻技术中的曝光方式就可以制备复杂多样的三维微结构，这些微结构在许多新型微机电系统（MEMS)中得到了越来越广泛的关注和应用。尽管倾斜/旋转紫外光刻技术已制备出复杂多样的微结构，但是目前只有少量的工作从倾斜曝光工艺中掩模的空间像以及Snell定律来解释倾斜微结构的成因，尚未建立相对完善的模型来分析倾斜/旋转光刻工艺中物理和化学过程对这些复杂三维微结构的影响。这对优化光刻工艺制作过程，提高微结构制作精度尤为重要。本文对倾斜/旋转紫外光刻技术的整个工艺过程作了初步的探讨，主要内容包括以下几个方面： 通过将标量基尔霍夫衍射理论与光学传输矩阵法相结合，并使用快速傅里叶变换技术处理，建立了适用于倾斜/旋转紫外光刻的成像模型(FDKM)。将该模型和光刻胶曝光剂量模型、厚胶曝光模型、后烘模型、显影模型相结合，可以模拟计算倾斜/旋转紫外光刻技术制备的三维微结构形貌。利用已建立的仿真模型对不同形状的微结构进行模拟，得到了其不同条件下的微结构形貌。此外，详细讨论了工艺参数对微结构特征参数和边墙角的影响，这些工艺参数包括：光刻胶厚度、入射光倾斜角度、间隙层厚度和光刻胶的吸收系数等等。 介绍了搭建的倾斜/旋转紫外光刻二维平台，包括曝光光源、光刻胶、掩模板、旋转平台等的一些关键技术参数。利用该实验平台开展了微结构制作实验，探索出一些简单微结构的最佳工艺条件，此外，实验过程中探究了各工艺过程量（包括曝光时间、后烘时间和温度以及显影时间）对最后形成微结构特征尺寸的影响，从而对倾斜/旋转紫外光刻模型进行验证。与第二章仿真模型给出的结果对比，两者有很好的一致性。 利用上述已经建立的仿真模型，我们研究了高深宽比柱状微结构在光刻胶厚度方向上畸变的特点，针对这一问题，我们提出了双面曝光和亮衬线、灰阶掩模相结合的办法，利用遗传算法对失真影响最大的区域进行搜索，光刻胶内部各层的衍射光场分布作为评价函数，对光刻过程引起的畸变进行优化。仿真结果显示，优化后光刻胶各层面型质量得到极大的改善，特征尺寸和边墙角等参数与理论值吻合得更好。本文提出的优化策略为优化高深宽比器件的性能提供了有力的支持和指导。需要指出的是，本文提出的算法可应用于接近式光刻不同的模型中，鉴于它的灵活性，其具有广泛的应用前景。 针对周期性光栅和医用微针两种微结构，开展光学和力学性能分析，为MEMS系统的设计提供充分的依据。 |
| 英文摘要 | Inclined/rotated UV lithography technique is a new UV lithography technique developed in recent years. By improving the exposure mode in the traditional UV lithography, it can fabricate various complex 3D microstructures. These microstructures attract more and more attention and are widely applied in many new MEMS. Though various complex 3D microstructures are acquired by the inclined/rotated UV lithography technique, few works on explaining the formation of the inclined microstructures by calculating the mask image in the inclined exposure process based on Snell's law have been done. Appropriate simulation model has not been set up to analyze influence of the physical and chemical processes on the 3D microstructures in the inclined/rotated UV lithography. It is important for the process optimization and the improvement of fabrication precision. Some discussion and research in the inclined/rotated UV lithography are presented in this paper. The detail work is listed as following: By combining the scalar Kirchhoff diffraction theory with the optical transfer matrix method and applying the fast Fourier transform technique, an exposure image model (FDKM,Frequency-domain Kirchhoff Method) for the inclined/rotated lithography is set up. Meanwhile，by combining FDKM method with the resist exposure dose model, the thickresist exposure model, postbake model and development model, we can calculate the 3D profiles of microstructure that applies the inclined/rotated UV lithography technique. Using the established simulation model, we simulate different microstructures, and obtain their profiles under different conditions. The influence on the microstructure feature size of several process parameters also have been studied in detail, including proximity distance, exposure inclined angle, resist thick, resist indexes, and resist extinction coefficient. Some important technological parameters of the inclined/rotated device which has been established are introduced, including the exposure light source, photoresist, mask and the inclined/rotated platform. Applying the platform, some experiments are carried out, and the optimum process conditions for some simple microstructure are discovered. In addition, the influence of several process parameters on the microstructure feature size in experiments also have been studied in detail, including exposure time, postbake time and development time. Compared with the results of simulation model which are given in chapter 2, they’re consistent with each other . Using the established simulation model above, we theoretically investigate the distortion characteristics of the two-dimensional slices of a high-aspect-ratio pillar microstructure in the thickness direction. Meanwhile, we propose an effective correction strategy that includes a double side exposure method and a combination of bright serif and gray-scale mask techniques. The parameters of mask shape and transmittance are optimized to correct the pattern distortions with the genetic algorithms. The diffracted light field modulation of various layers in the thick resist is employed as a merit function. Simulation results show that the pattern quality of internal layers of resist can be significantly improved by our proposed optimization method. The characteristic parameters such as feature size and sidewall angle match the original design goal. This study provides a theoretical support and favorable guidance for the actual process for optimizing the performance of high aspect ratio micro-structure device. It should be pointed out that, the established optimization algorithm in this paper can be extended to different simulation scenarios in proximity lithography. Due to its flexibility, it has a wide range of application . At the end, We analyzed the optical and mechanical properties of the periodic gratings and medical microneedle which can provide sufficient basis for the design of MEMS system. |
| 语种 | 中文 |
| 内容类型 | 学位论文 |
| 源URL | [http://ir.siom.ac.cn/handle/181231/16908]  |
| 专题 | 上海光学精密机械研究所_学位论文 |
| 推荐引用方式 GB/T 7714 | 何骏. 倾斜/旋转紫外光刻技术研究[D]. 中国科学院上海光学精密机械研究所. 2015. |
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