极紫外光刻聚光镜冷却优化及光机热分析

发布时间：2018-01-07 04:29

  本文关键词：极紫外光刻聚光镜冷却优化及光机热分析　出处：《哈尔滨工业大学》2015年硕士论文　论文类型：学位论文

  更多相关文章： 极紫外/X射线光刻 光源聚光镜 传热模型 冷却管布局优化 形变拟合 光机集成

【摘要】：光源聚光系统是极紫外光刻机的重要组成部分。随着光源功率的提高,聚光系统吸收的热量也越大。高温使聚光反射镜膜层使用寿命降低,镜体严重热变形,造成极紫外光线在后续中间焦点处大幅离焦,会聚光斑尺寸增大且能量分布非均匀性进一步加大。照明质量的下降最终会影响光刻质量和产量。为减小极紫外光刻聚光镜由于镜体温度差异引起的热形变,提高聚焦光斑的照明质量,本文以激光等离子光源(LPP)与Wolter型聚光系统为研究实例,对镜体背侧冷却管布局的优化进行了研究。分析并建立辐射源与镜体的热辐射模型,详细计算了镜体表面的非均匀热流分布,拟定冷却管总体布局方案;建立镜体热传导计算模型,采用冷却水热对流经验模型,再利用能量守恒关系式将三者统一到优化程序中,以各相邻冷却管间距为最终循环变量,以镜面温差范围最小为优化目标,完成了冷却管最优轴向间距的计算。结果表明,针对具有40kw功率的极紫外光源,聚光系统外层聚光镜仅在4根回路单管的布局下,利用上述冷却管间距优化方法,可将整个镜体温差控制在1℃范围内。分析过程及优化方法可为其他具有非均匀边界热流分布的光学系统反射镜的主动热控设计提供一定参考。为了进一步研究镜体残余温差对聚焦光斑质量的影响,本文采用了Zernike环多项式拟合镜面变形的方法。根据ANSYS有限元分析软件获得的镜体变形数据,拟合得到的Zemike环多项式系数,用自定义的INT文件将Zernike环多项式拟合的镜面变形导入到光学设计软件CODE V中,得到了镜面变形对聚焦光斑质量的影响,实现了光机集成分析。
[Abstract]:The condensing system of light source is an important part of the extreme ultraviolet lithography machine. With the increase of the power of the light source, the heat absorbed by the condensing system increases. The high temperature reduces the service life of the film layer of the condenser mirror, resulting in the serious thermal deformation of the mirror body. This results in a large defocus of the extreme ultraviolet ray at the subsequent intermediate focal point. The size of the convergent spot increases and the inhomogeneity of the energy distribution increases further. The decrease of illumination quality will eventually affect the lithography quality and output. In order to reduce the thermal deformation caused by the temperature difference of the mirror in the extreme ultraviolet lithography condenser. In order to improve the illumination quality of focusing spot, this paper takes LPP (laser plasma light source) and Wolter type condensing system as examples. The optimization of the collocation of the cooling tube on the back side of the mirror is studied. The thermal radiation model of the radiation source and the mirror body is established, and the non-uniform heat flux distribution on the surface of the mirror is calculated in detail, and the overall layout scheme of the cooling tube is drawn up. The heat conduction calculation model of vitrinite is established. The empirical model of heat convection in cooling water is adopted, and the energy conservation relation is used to unify the three models into the optimization program. The distance between the adjacent cooling tubes is taken as the final cycle variable. The optimum axial distance of cooling tube is calculated with the minimum temperature difference range of mirror surface as the optimization objective. The results show that for the extreme ultraviolet light source with 40kw power. The outer layer condenser of the condensing system is optimized by the above method under the arrangement of only four single tubes. The temperature difference of the mirror can be controlled in the range of 1 鈩，

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