点衍射干涉仪小孔掩模制备与检测技术研究

Research of Preparation and Detection Technology of PDI Pinhole Mask

在点衍射干涉仪中小孔掩模的主要作用是衍射产生接近理想的球面波用于干涉测量,其直径、圆度及三维形貌对测量精度有决定性影响。分析了聚焦离子束刻蚀、电子束曝光等加工技术的加工原理、加工精度及技术特点。采用优质航空铝,利用单点金刚石机床和聚焦离子束设备,采用精密制备工艺,分别制备了小孔直径1.47μm和1.11μm的小孔掩模并利用扫描电子显微镜对其进行了检测。实验结果表明,聚焦离子束刻蚀是实现直径微米量级的小孔加工的有效手段,为获得较好的圆度和三维形貌,小孔掩模加工区域需保证较小的深径比。

The main role of the pinhole mask of point diffraction interferometer is diffracted to produce a nearly ideal spherical wavefront for interferometry.The quality of the reference wavefront depends on the pinhole diameter,roundness and dimensional morphology.The pinhole mask processing technologies are summarized.The machining mechanism,precision and technical features of focused ion beam etching and electron beam lithography are expounded.Using high-quality aviation aluminum and single point diamond lathe and focused ion beam device.The pinhole diameter of 1.47μm and 1.11μm mask were prepared using precision technology and were mesured by scanning electron microscopy.The experimental results show that,the focused ion beam etching is the effective means to realization micro scale pinhole mask.In order to obtain better roundness and three-dimensional topography of pinhole,the pinhole mask processing area need to ensure a smaller depth to diameter ratio.