EUV Mask Flare Correction via Dummy Pattern Evaluation
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Solution Overview
Problem
In EUV lithography, the short wavelength of the light source causes significant scattering, leading to light leakage and variations in resist pattern size due to flare, which existing technologies struggle to precisely control and correct.
Innovation Solution
A pattern generating method that evaluates flare and adds a dummy mask pattern to ensure uniform flare intensity, performing optical proximity correction and flare correction to stabilize resist pattern sizes during EUV exposure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If EUV lithography with short wavelength is used, then resolution and scaling down are improved, but scattering increases causing flare and light leakage
Solution Approach 1:
The patent converts the harmful flare effect into a useful tool for measurement and correction. By intentionally introducing dummy patterns that generate controlled flare, the system can measure and characterize the flare effect, then use this information to correct the main patterns. The harmful scattering is thus transformed into a measurable and correctable phenomenon.
Solution Approach 2:
The patent introduces dummy patterns as intermediary elements that mediate between the EUV light source and the main patterns. These dummy patterns act as a buffer to generate and distribute flare uniformly across the exposure field, protecting the main patterns from uneven flare effects and enabling precise measurement and correction.
2Manufacturing precision
If dummy patterns are added around patterns to be evaluated, then uniform flare intensity is achieved, but mask pattern complexity increases
Solution Approach 1:
The patent extracts the dummy patterns from the final product design and treats them as separate, temporary evaluation elements. These dummy patterns are added only for measurement and correction purposes, then their effects are used to adjust the main patterns without including the dummy patterns themselves in the final product.
Solution Approach 2:
The patent performs preliminary measurement and correction actions using dummy patterns before finalizing the main pattern design. The dummy patterns are introduced in advance to characterize the flare effect, enabling pre-correction of the main patterns to compensate for expected flare variations.
3Manufacturing precision
If flare correction and optical proximity correction are performed, then pattern accuracy is improved, but calculation and processing complexity increases
Solution Approach 1:
The patent implements a feedback mechanism where dummy patterns provide measurement data about actual flare effects, which is then used to adjust and correct the main patterns. The system continuously refines the correction based on measured flare characteristics, creating a closed-loop process that improves accuracy through iterative optimization.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method effectively reduces flare-induced variations in resist pattern sizes, ensuring precise control over lithography margins and exposure conditions, thereby improving the accuracy and consistency of pattern formation.
Implementation Method 1
a wavelength of the light source is shorter than that of an argon fluoride (ArF) light source. Thus this exposure apparatus generates large scattering in a reduction optical system. The scattered light (flare) may cause light leakage from an opening portion of a mask pattern
Data Source
AI summary
One embodiment includes: a step of evaluating an amount of flare occurring through a mask at EUV exposure; a step of providing a dummy mask pattern on the mask based on the evaluated result of the amount of flare; and a step of executing a flare correction and an optical proximity correction on a layout pattern. The layout pattern is provided by the EUV exposure through the mask with the dummy mask pattern.