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Method for optimizing three-dimension phase-shifting mask (PSM) based on boundary layer (BL) model

A technology of phase shift mask and optimization method, which is applied in the field of photolithography resolution enhancement, and can solve problems such as high computational complexity, low optimization efficiency, and high complexity

Active Publication Date: 2011-09-14
BEIJING INSTITUTE OF TECHNOLOGYGY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the above methods generally have the following three deficiencies: first, the above methods independently optimize the topology and phase of the PSM, so they cannot achieve the global optimum; second, the above methods do not use the gradient information of the optimization objective function Guide the optimization direction of PSM, so the optimization efficiency is low; third, the above methods all use the rigorous three-dimensional mask imaging model to optimize the PSM, and the computational complexity is very high, which leads to the high complexity of the above PSM design method

Method used

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  • Method for optimizing three-dimension phase-shifting mask (PSM) based on boundary layer (BL) model
  • Method for optimizing three-dimension phase-shifting mask (PSM) based on boundary layer (BL) model
  • Method for optimizing three-dimension phase-shifting mask (PSM) based on boundary layer (BL) model

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Experimental program
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Embodiment 1

[0206] Such as Figure 13 An example is shown for the first lithography system. 1301 is a target graphic. 1302 is the initial PSM mask, its corresponding Γ shape is consistent with the target pattern, white represents the 0° phase opening, black represents the 180° phase opening, and gray represents the light blocking part. 1303 is imaging in the air of the photolithography system after using 1302 as a mask, and the imaging error is 557.6. Here the imaging error is defined as the value of the objective function.

[0207] Such as Figure 14 As shown, 1401 is a two-dimensional optimized mask pattern obtained when the three-dimensional effect of the mask is not considered. When optimizing a two-dimensional mask, replace F in the above algorithm with Γ TE and F TM . 1402 is the air imaging of the first photolithography system after using 1401 as the mask, and its imaging error is 360.0. 1403 and 1404 are the air imaging corresponding to the 0° phase opening and the 180° pha...

Embodiment 2

[0210] Such as Figure 16 An example is shown for the second type of lithographic system. 1601 is a target graphic. 1602 is the initial PSM mask, its corresponding Γ shape is consistent with the target pattern, white represents the 0° phase opening, black represents the 180° phase opening, and gray represents the light blocking part. 1603 is the imaging in air of the second photolithography system after using 1602 as a mask, and the imaging error is 994.1.

[0211] Such as Figure 17 As shown, 1701 is a two-dimensional optimized mask pattern obtained when the three-dimensional effect of the mask is not considered. 1702 is the air imaging of the second photolithography system after using 1701 as the mask, and its imaging error is 598.2. 1703 and 1704 are the air imaging corresponding to the 0° phase opening and the 180° phase opening respectively. There is an imbalance between 1703 and 1704 due to the three-dimensional effect of the mask.

[0212] Such as Figure 18 As sh...

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Abstract

The invention discloses a method for optimizing a three-dimensional phase-shifting mask (PSM) based on boundary layer (BL) model. The method comprises the following steps of: constructing an optimal objective function D as the square of an Euler distance of image difference between an objective pattern and air; guiding a PSM optimization direction by utilizing gradient information of the optimal objective function; optimizing a topological structure of the PSM and the phase of the electric-field intensity after light rays pass through the opening of the PSM; and judging whether the objective function is reduced during the optimization. Therefore, the imaging error can be stepwise reduced during the optimization of the three-dimensional PSM to further improve the imaging resolution. Meanwhile, the method has high optimal efficiency and low computation complexity.

Description

technical field [0001] The invention relates to a three-dimensional phase shift mask optimization method based on a boundary layer (boundary layer, BL) 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 is mainly divided into four parts: illumination system (light source), 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 enters the wafer 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 size of the circuit is much smaller than...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G03F1/14G03F1/00
Inventor 马旭贡萨洛·阿尔塞李艳秋
Owner BEIJING INSTITUTE OF TECHNOLOGYGY