Diffractive optics play a key role in hard X‐rays imaging for which many scientific, technological, and biomedical applications exist. Herein, high‐aspect‐ratio microfabrication of gratings for X‐ray interferometry is demonstrated using Pt as a catalyst for the metal assisted chemical etching of Si in a solution of HF and H₂O₂. The Pt layer is thermally treated to realize a porous catalyst layer that stabilizes the etching of a pattern with a pitch size from 4.8 to 20 μm in the direction perpendicular to the <100> Si substrate and an aspect ratio up to 60:1. The superior etching performance of Pt as a catalyst and its stability in a solution with high HF content are reported in direct comparison with the Au catalyst for the same grating parameters. The Si structure is then used as a template for filling with Au, as a high absorbing X‐ray material. The Pt catalyst layer is used as a conductive seed for Au electroplating. The quality of the overall process is assessed by obtaining a visibility map using 30 μm‐thick Au grating in an X‐ray interferometric setup at 20 keV.

中文翻译：

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通过铂辅助化学蚀刻和金电镀实现高纵横比光栅微加工

在许多科学，技术和生物医学应用中，衍射光学在硬X射线成像中起着关键作用。本文中，使用Pt作为催化剂在HF和H ₂ O ₂溶液中对金属进行金属硅化学腐蚀的催化剂，证明了用于X射线干涉测量的光栅的高纵横比微加工。。对Pt层进行热处理，以实现多孔催化剂层，该催化剂层在垂直于<100> Si衬底的方向上以4.8至20μm的节距尺寸和高至60：1的纵横比稳定图案的蚀刻。在相同的光栅参数下，与Au催化剂直接比较，据报道Pt作为催化剂的优异蚀刻性能及其在高HF含量的溶液中的稳定性。然后将Si结构用作填充Au的模板，作为高吸收X射线材料。Pt催化剂层用作Au电镀的导电种子。通过在20 keV的X射线干涉仪中使用30μm厚的Au光栅获得可见度图来评估整个过程的质量。