Development of a surface gradient integrated profiler for the next generation high accuracy mirror

为了发展X射线自由电子激光源，实现纳米聚焦和高相干性的超精密非对称反射镜是必不可少的。极紫外光刻技术是一种很有发展前途的半导体器件制造技术，工业上需要高精度的非对称镜，研制表面梯度集成轮廓仪可用于下一代高精度非对称镜。新的轮廓仪是基于没有参考表面的激光的直线度。性能分析器的性能如下。反射镜轮廓的测量精度为1 nmPV。旋转角测量的分辨率为0.17 μrad。测量时间为5 min/样品。用轮廓仪测量了半径为400 mm的球面镜。二维轮廓测量的重复性小于1 nm。用该轮廓仪对R = 400 mm的球面镜进行了轮廓测量，并与用Fizeau干涉仪和三坐标测量机测量的结果进行了比较。通过使用轮廓仪测量的轮廓与通过使用其他轮廓仪测量的轮廓在约10 nm内一致。这些轮廓的差异分别基于系统误差。

In order to develop X-ray free electron laser sources, the ultraprecision asymmetric mirrors which realize nano-focusing and high coherence are indispensable. In industry, the high accurate asymmetric mirrors are required for extreme ultraviolet lithography which is a promising fabrication technology for semiconductor devices.A surface gradient integrated profiler can be developed for the next generation high accuracy asymmetric mirrors. The new profiler is based on the straightness of laser light without a reference surface. The performances of the profiler are as follows. The accuracy of measurement of the mirror profile is 1 nmPV. The resolution of measurement of the rotation angle is 0.17 μrad. And the time of measurement is 5 min/sample. A spherical mirror with a radius of 400 mm is measured by the profiler. The repeatability of two-dimensional profile measurements is less than 1 nm. The profile of the spherical mirror with R = 400 mm to be measured by using the profiler is compared with that measured by using the Fizeau interferometer and coordinate measuring machine. The profile measured by using the profiler coincides with that measured by using other profilers, within approximately 10 nm. These differences of profiles are based on systematic errors, respectively.