Preparation method of high opening area critical angle transmission grating

Abstract

The invention discloses a method for preparing a high opening area critical angle transmission grating, comprising the following steps: S1, preparing a mask; S2, depositing a silicon nitride layer on both sides of a single crystal silicon substrate, and then spinning the silicon nitride layer on the surface of the silicon nitride layer. Apply photoresist, align the mask plate with the single crystal silicon substrate, after exposure and development on both sides respectively, transfer the pattern in the mask plate to the single crystal silicon substrate to obtain the reference grating; S3, place the reference grating on the single crystal silicon substrate Chromium plating on both sides of the area, and then double-sided spin-coating of photoresist, and the support structure is obtained after exposure and development; S4, after double-sided spin-coating of photoresist on the support structure of the single crystal silicon substrate, and then double-sided exposure; S5, and then through Dry etch the silicon nitride layer, wet etch the single crystal silicon, and finally remove the silicon nitride layer to obtain the transmission grating. The preparation method of the present invention can realize high-precision double-sided exposure through the scanning interference field exposure method, and prepare a mask pattern with high phase double-sided matching precision for double-sided etching, thereby reducing the widening area.

Description

technical field [0001] The invention relates to the technical field of grating preparation. More specifically, the present invention relates to a method for preparing a high opening area critical angle transmission grating. Background technique [0002] The main manufacturing processes of self-supporting transmission gratings are Bosch deep reactive ion etching and anisotropic wet etching of <110> silicon wafers. The Bosch process has been replaced by the anisotropic wet etching process of <110> monocrystalline silicon for reasons such as high requirements for protective masks, complex manufacturing processes, and poor sidewall roughness. However, the critical angle transmission grating lines and self-supporting structure obtained by anisotropic wet etching depend on the crystal orientation of single crystal silicon, and the self-supporting structure expands to the bottom and occupies most of the area as the etching depth increases. As a result, the effective a...

AI Technical Summary

Problems solved by technology

However, the critical angle transmission grating lines and self-supporting structure obtained by anisotropic wet etching depend on the crystal orientation of single crystal silicon, and the self-supporting structure expands to the bottom and occupies most of the area as the etching depth increases. As a result, the effective area of ​​the grating is reduced, which currently only accounts for about 30% of the aperture of the grating

The X-ray transmission space telescope with critical angle transmission as the core component needs a large total effective area of ​​the grating (the total effective area of ​​IXO > 1000cm 2 ) to improve the overall signal-to-noise ratio and sensitivity, which requires a larger number of gratings, resulting in a substantial increase in the overall volume and weight of the telescope system, increasing manufacturing difficulty and launch costs

Images