A Fast and Rigorous Simulation Method for the Diffraction Spectrum of a Defect-Free Mask in Extreme Ultraviolet Lithography

Abstract

A rapid and rigorous simulation method for the diffraction spectrum of a defect-free mask in extreme ultraviolet lithography. The equivalent film layer method is used to calculate the complex reflection coefficient of the film layer by layer from top to bottom to obtain the complex reflection coefficient of the entire multilayer film. The mask model calculates the mask absorption layer diffraction spectrum, then passes through the multi-layer film reflection, and finally passes through the absorption layer thin mask model again to obtain the EUV lithography defect-free mask diffraction spectrum. The method of the invention can rapidly and accurately simulate the diffraction spectrum of the extreme ultraviolet lithography defect-free mask.

Description

technical field [0001] The invention relates to an extreme ultraviolet lithography mask, in particular to a fast and strict simulation method for the diffraction spectrum of a defect-free extreme ultraviolet lithography mask. Background technique [0002] As the most promising next-generation lithography technology, extreme ultraviolet (EUV) lithography is a reasonable extension of deep ultraviolet (DUV) lithography to shorter wavelengths. In the development process of EUV lithography process, it is necessary to use lithography simulation to reduce the cost of process development and shorten the development cycle. Different from DUV lithography, EUV lithography uses a reflective mask, and the thickness of the mask is much larger than the wavelength of the incident light. At this time, the traditional scalar diffraction theory is no longer applicable. In order to meet the needs of process development and large-area mask simulation, Accurate and fast masking simulation method...

AI Technical Summary

Problems solved by technology

In this method, the Kirchhoff correction model is used for the absorption layer, and the multilayer film is approximated by a plane mirror, and the compensation distance of the phase propagation is obtained by matching with the strict simulation. Compared with the strict simulation, the simulation speed has been greatly improved, and The analytical expression of the diffraction spectrum of the mask is given, but the method of using plane mirrors to approximate the complex reflection coefficient of the multilayer film in this technology can only effectively calculate the diffraction orders within the range of 15 degrees of diffraction angle, which makes the simulation results inconsistent with the strict simulation. certain error

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