EUV Photomask Position Compensation for Multilayer Stress
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Solution Overview
Problem
In EUV lithography, photomasks with multilayer films experience pattern displacement due to stress release during processing, leading to deviations in the mask pattern position, which affects manufacturing yield and pattern accuracy.
Innovation Solution
A photomask manufacturing method that compensates for positional variations by forming the mask pattern at a deviated position to account for stress relief, using techniques like Reactive Ion Etching and Electron Beam exposure, and applying corrections through CAD data to ensure the pattern is formed at the target position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a multilayer film is used for the photomask in EUV lithography, then the light shielding performance and reflectivity are improved, but stress release during processing causes pattern position deviation
Solution Approach 1:
The patent applies preliminary action by calculating the stress release amount before pattern formation and pre-compensating the mask pattern position. The correction amount is determined based on multilayer film thickness and stress characteristics before the actual patterning process, allowing the pattern to be formed at a corrected position that accounts for anticipated stress release during subsequent processing steps.
2Ease of manufacture
If the mask pattern is formed at the target position without compensation, then the manufacturing process is simple, but stress relief causes the pattern to deviate from the target position
Solution Approach 1:
The patent performs preliminary calculation of the correction amount based on multilayer film characteristics before pattern formation. This allows the mask pattern to be intentionally formed at a corrected position that compensates for anticipated stress release, maintaining manufacturing simplicity while achieving high position accuracy.
3Reliability
If the multilayer film thickness is increased to improve light shielding, then the light shielding performance is improved, but the stress release amount increases causing greater position deviation
Solution Approach 1:
The patent applies parameter changes by establishing a quantitative relationship between multilayer film thickness and stress release amount. The correction amount is calculated based on the actual film thickness parameter, allowing dynamic adjustment of the pattern position compensation to maintain accuracy regardless of film thickness variations.
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
This method improves overlay accuracy and manufacturing yield in EUV lithography by accurately positioning the mask pattern, reducing the impact of stress-related deviations and enhancing the light shielding performance of the photomask.
Implementation Method 1
a mask pattern is formed at a deviated position altered by the amount of positional variation from a target position
Implementation Method 2
using techniques like Reactive Ion Etching and Electron Beam exposure
Data Source
AI summary
According to one embodiment, a photomask manufacturing method for patterning a multilayer film into a mask pattern in the multilayer film is provided. The photomask manufacturing method includes preparing a substrate including the multilayer film provided on the substrate, obtaining an amount of position variation before and after the multilayer film is patterned if a position of the mask pattern is deviated before and after patterning the multilayer film, forming the mask pattern at a position deviated by the amount of the position variation from a target position, if the multilayer film is patterned and a pattern of the multilayer film is formed at the target position, and patterning the multilayer film with the mask pattern.