超高导向精度的光刻物镜补偿机构研究

Compensating mechanism is the core component in the lithographic lens which is by far the most precision and sophisticated optical instrument. For the application of the lithographic lens employed in the manufacture of 38nm feature size integrated circuit, compensating mechanism need to reach nanometer regulation precision and guiding precision. Research on nanometer regulation precision is familiar, but scanty on nanometer guiding precision. Aiming at the characteristic of the lithographic lens, this project proposes a novel structural configuration: annular flexible parallelogram for the realization of ultrahigh guiding precision, and investigates the influencing factor and promotion method of the guiding precision for the compensating mechanism. Firstly, the parameterized model of the novel structural configuration will be established. Influencing factor of the guiding precision will be investigated and identified. Secondly, the error model of the compensating mechanism will be established. The influence of the structural configuration, fabrication tolerance, alignment tolerance and actuation error acting on the guiding precision will be analyzed. Finally, the promotion method of the guiding precision caused by various kinds of influencing factor will be investigated and verified by experiment. The research of this project will establish a basis for the promotion of the ultrahigh guiding precision for the compensating mechanism used in the lithographic lens, and provide valuable theoretical meaning for the in-depth investigation and development of this technology. Besides meeting the national major requirement, this technology also has comprehensive application prospect in the field of micro/nano adjusting and positioning, micro/nano sensing.

光刻物镜是迄今最精密、最复杂的光学仪器，补偿机构是光刻物镜中的核心组件。38nm特征线宽集成电路制造所需的光刻物镜中补偿机构的调节精度和导向精度均需达到纳米级。纳米级调节精度的研究较多，纳米级导向精度的研究却很少涉及。本项目针对光刻物镜的应用特点，提出了一种适用于超高导向精度补偿机构的圆环形柔性平行四边形新结构构型，研究补偿机构导向精度的影响因素与提升方法。首先，建立新结构构型的参数化模型，考察、验证导向精度的影响因素；其次，建立补偿机构的误差模型，分析结构构型、制造与装配公差、驱动误差对导向精度的影响规律；最后，研究各影响因素下导向精度的提升方法，并开展试验验证。本项目的研究将为光刻物镜补偿机构超高导向精度的实现与进一步提升奠定基础，对该技术的深入研究和发展具有重要的理论意义。该技术除可满足国家重大需求外，在微纳调节与定位、微纳传感等领域亦具有广泛的应用前景。

项目瞄准国家集成电路产业的重大需求，针对光刻机投影物镜补偿机构超高导向精度需求，系统地开展了补偿机构结构构型设计与实现，研制了补偿机构导向精度测试装置，研究了补偿机构的制造误差、装配误差及驱动误差对导向精度的影响规律，实现了补偿机构导向精度的提升。.项目提出了一种圆环形柔性平行四边形结构，并以此为基础构建了新型超高导向精度的补偿机构，实现了结构的Z向柔度与水平向柔度之比在6000:1以上，二阶模态频率与一阶模态频率之比达40以上。提出采用一体式柔性环片实现圆环形柔性平行四边形结构，通过多轮次加工攻关，实现了柔性环片的薄壁部位尺寸偏差达4μm以内，厚度公差达3μm以内，保证了0.15mm厚的薄壁金属件加工后达到±2μm的公差要求，证明了圆环形柔性平行四边形结构可行性。研制了补偿机构导向精度测试装置，实现了位移测量精度3nm，角度测量精度5msec（25nrad），结果优于项目申请时提出位移测量精度5nm的技术目标，为补偿机构导向精度的评价提供了有力的基准。全面测试了补偿机构的性能：补偿机构的一阶模态253Hz，调节行程±120μm，调节速度2μm/0.08s，调节精度±10nm，导向误差占调节行程的0.02%，补偿机构的性能预期可满足光刻物镜未来5~10年的应用需求。详细分析了补偿机构的各项制造误差、装配误差、驱动误差对补偿机构导向精度的影响，通过改进与提升，实现了在补偿机构全行程，导向精度高，导向误差的重复性好、线性好，利于在光刻物镜及其他场合中应用。.结合项目实施，将项目的相关研究成果应用于多种型号的光刻物镜，应用于面形干涉仪移相器等其他场合。项目实施过程中研制的补偿机构导向精度测试装置已作为物镜批量生产的保障设备，用于批量生产时光刻物镜补偿机构的重复性与互换性检测。