双波长二维光栅纳米级平面位移测量方法的研究

Nanometer measurement is the key technology of developing the advanced manufacturing, and is also the forerunner and foundation of the entire field of nanotechnology. In this project, a method of nanometer planar displacement measurement with a dual-wavelength laser and a two-dimensional grating is proposed. By utilizing two sets of orthogonal diffraction light generated by the two-dimensional grating, displacements in both directions are obtained. As a result, Abbe errors and vertical deviation between two axial caused by the stacked structure can be eliminated when two sets of independent one-dimensional measuring device are installed. By utilizing the dual-wavelength laser, a carrier wave is introduced into signals of the interference fringes which change with the displacement or time. Therefore, the DC signal system for the ordinary grating interferometer measurement can be transformed into the AC signal system, which can improve largely the anti-jamming capability and stability of the measurement system. Some key scientific problems, such as the corresponding relationship between the planar displacement and the change of characteristic signal in the interference field, the coupling mechanism and decoupling algorithm between the measured parameters in x and y directions, the impacting mechanism about the diffraction characteristics of two-dimensional grating upon the measurement accuracy, measurement error analysis and comprehensive performance assessment of the measurement system, will be investigated in this research. An innovative heterodyne grating interferometry planar displacement measurement system with high-precision, high-integration, strong anti-jamming and larger range (such as 40mm*40mm) will be constructed. The main work and contributions to be obtained in our research will help improve the independent innovation ability for nanometer-scale measurement instrument with lower cost in China's ultra-precision manufacturing industry, and it is important practical significance to further promote the development of the advanced manufacturing technology.

纳米测量是先进制造业发展的关键技术，也是整个纳米科技领域的先导和基础。本项目提出了双波长二维光栅纳米级平面位移测量方法，利用二维光栅的两组正交衍射光实现两个方向的位移测量，以消除两套独立的一维测量装置安装时堆栈式结构带来的阿贝误差和两轴向之间的垂直度偏差；采用双波长激光，给干涉条纹随位移（或时间）的变化引入一个载波，使普通光栅测量的直流信号系统转变为交流信号系统，大大增强系统的抗干扰能力和稳定性。通过研究干涉场特征信号变化与平面内位移量的对应机理、x和y两方向的测量参数耦合机理及解耦算法、二维光栅衍射特性对测量精度的影响机理、测量误差分析及性能综合评估等关键科学问题，构造高精度、高集成度、抗干扰性强且具有较大量程（如40mm*40mm）的外差式光栅干涉平面位移测量系统。其研究成果将提高我国超精密加工中较低价位纳米级测量仪器的自主创新能力，对进一步推动先进制造技术的发展具有重要的现实意义。

纳米测量是先进制造业发展的关键技术，也是整个纳米科技领域的先导和基础，对国民经济发展与科技进步具有重要意义。本项目首次将双波长激光与二维光栅相结合，构造了具有大量程、高精度、高稳定性特点的外差干涉纳米级平面位移测量系统。提出了一种基于对角线衍射级次的二维外差干涉光栅位移测量方法，配合所提出的解耦方法与交叉光栅，保证了高光学细分、高对比度与高信噪比的同时获得。提出并研制了基于单层和双层交叉矩形结构的两种二维计量光栅，分别利用掩膜光刻方法和全息光刻方法对其进行了制作，并实验验证了所制作二维光栅的有效性。研制了双波长二维光栅纳米级平面位移测量系统，分别利用线性位移、平面位移、直线度、稳定性实验对其进行了测试，结果显示其测量量程为60mm*60mm，X与Y方向的位移分辨率均为0.125nm、小量程重复性分别为2.2nm与2.5nm、10分钟下的系统稳定性分别为4nm和6.5nm，且可以有效实现X与Y方向的直线度误差测量。同时建立了包含二维光栅横滚角、俯仰角、偏航角、非正交角在内的几何误差通用数学模型，定量研究了余弦误差与耦合误差同各误差角、衍射级次、衍射次数和光学细分倍数的关系。提出了一种将自标定与比较式标定相结合的二维系统几何误差补偿方法，并实验验证了所提出方法的有效性。以上研究成果有助于提高我国超精密加工中较低价位纳米级测量仪器的自主创新能力，对进一步促进先进制造技术的发展具有重要的现实意义。