Light source-mask mixed optimizing method based on Abbe vector imaging model

Abstract

The invention provides a light source-mask mixed optimizing method based on an Abbe vector imaging model. The method comprises the following steps of: setting a light source image pixel value and transmittances of a mask opening part and a light-stopping part, setting variable matrixes [omega]S and [omega]M, constructing a target function D into a square of an Euler distance between a target image and an image formed in the corresponding photoresist of the current light source and mask, and guiding the mixed optimization of the light source and mask image by using the variable matrixes [omega]S and [omega]M and the target function D. Compared with the traditional light source single optimizing method, mask single optimizing method, light source-mask simultaneous optimizing method and light source-mask alternative optimizing method and the like, the method disclosed by the invention can more effectively improve the resolution ratio of a photoetching system. Simultaneously, the light source and mask optimized by the method disclosed by the invention are applicable to conditions of small numerical aperture (NA), as well as applicable to the conditions that NA is greater than 0.6. Moreover, according to the invention, light source images and mask images are optimized through optimizing the gradient information of the target function and combining with a steepest descent method, and the optimizing efficiency is high.

Description

technical field [0001] The invention relates to a light source-mask hybrid optimization method based on an Abbe (Abbe) vector imaging model, and belongs to the technical field of lithographic resolution enhancement. Background technique [0002] The current large-scale integrated circuits are generally manufactured using photolithography systems. The lithography system mainly includes four parts: illumination system (including light source and condenser), mask, projection system and wafer. The light emitted by the light source is focused by the condenser and then enters the mask, and the opening part of the mask transmits light; after passing through the mask, the light is incident on the wafer coated with photoresist through the projection system, so that the mask pattern is copied on the wafer. [0003] The current mainstream lithography system is the 193nm ArF deep ultraviolet lithography system. As the lithography technology node enters 45nm-22nm, the critical dimension...

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Problems solved by technology

However, the above method only utilizes the SISMO method to optimize the light source and mask pattern, and does not comprehensively utilize the advantages of other methods (such as SO and MO methods, etc.), so its optimization effect is relatively poor compared with the HSMO method involved in the present invention.

In addition, the above-mentioned SISMO method is based on the scalar imaging model of the lithography system, so it is not suitable for the lithography system with high NA

At the same time, due to

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