Fabrication of astronomical x-ray reflection gratings using thermally activated selective topography equilibration

TL;DR

This paper introduces TASTE, a thermal process for creating 3D resist structures for X-ray reflection gratings, demonstrating its potential for astronomical applications.

Contribution

It presents a novel thermal reflow technique for fabricating blazed gratings with specific periodicities in resist materials.

Findings

Successfully fabricated gratings with 840 nm and 400 nm periodicities.

Demonstrated the creation of wedge-like structures suitable for X-ray reflection.

Discussed integration of TASTE into existing grating fabrication processes.

Abstract

Thermally activated selective topography equilibration (TASTE) enables the creation of 3D structures in resist using grayscale electron-beam lithography followed by a thermal treatment to induce a selective polymer reflow. A blazed grating topography can be created by reflowing repeating staircase patterns in resist into wedge-like structures. Motivated by astronomical applications, such patterns with periodicities 840 nm and 400 nm have been fabricated in 130 nm-thick PMMA using TASTE to provide a base for X-ray reflection gratings. A path forward to integrate this alternative blazing technique into grating fabrication recipes is discussed.