Fast simulation method for extreme ultraviolet photoetching thick mask defects

Abstract

The invention discloses a fast simulation method for extreme ultraviolet photoetching thick mask defects. The method is implemented through that a defect multilayer membrane is equivalent to a defect-free plane mirror and a defect panel mirror; firstly, the diffraction spectrum of a mask absorption layer is obtained through thin-mask approximation, and the mask absorption layer subjected to phase compensation is reflected through the defect multilayer membrane; then, an operation of phase compensation is performed again; and finally, through thin-mask approximation and phase compensation, the mask diffraction spectrum of extreme ultraviolet photoetching defects is obtained. According to the invention, the influence of defects on mask imaging can be effectively simulated, and the simulation speed of extreme ultraviolet photoetching thick mask defects can be improved.

Description

technical field [0001] The invention relates to an extreme ultraviolet lithography mask, in particular to a fast simulation method for defects in an extreme ultraviolet lithography thick mask. Background technique [0002] Mask defects are one of the major hurdles in the development of EUV lithography. Mask defects greatly affect the reflectivity of multilayer films of EUV lithography masks, so certain methods are needed to compensate, and accurate and fast simulation of the influence of mask defects on mask imaging is the main basis for compensation and large Area masking is really required. Therefore, it is of great significance to study fast and accurate mask defect simulation methods. [0003] At present, extreme ultraviolet lithography mask simulation usually adopts a rigorous simulation method to solve the mask diffraction field distribution, such as the FDTD method (see prior art 1, T.Pistor, Y.Deng, and A.Neureuther, "Extreme ultraviolet mask defect simulation: lo...

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Problems solved by technology

In this method, the diffraction spectrum is calculated by decomposing the mask structure, the absorption layer adopts a thin mask model and point pulse correction, the multilayer film is approximated by a plane mirror, and the compensation distance of phase propagation is obtained by comparing with strict simulation, which is comparable to the prior art 2 Compared with the mask pattern period of 44nm, the characteristic size of 22nm, and the error within 3%, the operation speed is increased by nearly 100 times, and this method gives the analytical expression of the mask diffraction spectrum, but this simulation method can only be used Due to the lack of defect masking simulation, the scope of application of this method is limited

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