Diffraction grating structure and preparation method thereof

Abstract

The invention provides a diffraction grating structure, which comprises a plurality of repeated periodic structures, each periodic structure comprises at least one grating ridge and a grating groove,each periodic structure comprises a plurality of parts from the central position to the outside, each part is the grating ridge or the grating groove, and the depth of each part meets a preset condition when each part is the grating groove. On the other hand, the invention further provides a preparation method of the diffraction grating structure. By reasonably setting the position and the depth of the gate groove, the seventh diffraction order has high diffraction efficiency, the diffraction efficiency of all even diffraction orders is zero, and the problem that an existing diffraction grating has even diffraction orders, especially high zero diffraction orders, is well solved.

Description

technical field [0001] The present disclosure relates to the field of semiconductors, in particular to a diffraction grating structure and a preparation method thereof. Background technique [0002] In the field of semiconductor, integrated circuit and precision measurement technology, phase grating position sensors are often used to observe the position information of the target. The phase grating is used as a measurement mark to generate diffracted beams by acting on incident light. Among them, odd diffraction orders are used to generate measurement signals. , the high diffraction order in the odd diffraction order is used to improve the measurement accuracy. Due to the limitation of the diffraction characteristics of the grating, the measurement signal of the high-diffraction order is weak, which reduces the signal-to-noise ratio of the measurement signal, resulting in poor stability of the measurement signal and reducing the repeatability of position measurement. Howeve...

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Problems solved by technology

[0004] The disclosure provides a diffraction grating structure and a preparation method thereof, which better solves the problem of even diffraction orders, especially the strong zero diffraction order, in existing diffraction gratings

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