Comparative Characteristics of Microelectronic Deep Etching Technologies for X-ray Optics Applications

A comparative analysis of two microtechnologies for manufacturing silicon planar X-ray optics was presented: the Bosch process and cryogenic plasma etching. Comprehensive analysis using scanning electron microscopy (SEM), atomic force microscopy (AFM), and X-ray interferometry demonstrated that cryogenic etching enables manufacturing of surfaces with exceptionally low local sidewall roughness (3.6 nm RMS on 2 × 2 µm area). The X-ray interferometric technique demonstrated high sensitivity to the integral surface quality, establishing a correlation between surface morphology and optical characteristics. The results have great significance for developing next-generation X-ray optics that minimizes wavefront distortions of coherent beams.