EUV Mask Measurement Data Correction for Stress-Induced Warping
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Solution Overview
Problem
The challenge lies in accurately measuring and compensating for internal stresses in photolithographic masks for the extreme ultraviolet (EUV) wavelength range, which cause warping and distortions, affecting the placement of pattern elements and the overall precision of EUV masks during the transition from production to operational environments.
Innovation Solution
A method that involves determining measurement data influenced by internal stresses, ascertaining changes during transition to new surroundings, and correcting these data to account for stress compensation, using techniques such as finite element simulations and anchoring methods to ensure accurate placement and flatness of EUV masks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If measurement data is determined in first surroundings, then measurement can be performed, but internal stresses cause warping and placement inaccuracies
Solution Approach 1:
The patent applies preliminary action by determining measurement data in first surroundings before the mask transitions to second surroundings, and by ascertaining changes during transition. This allows the system to predict and compensate for placement inaccuracies caused by internal stresses before they affect operational reliability, ensuring accurate pattern element placement throughout the mask lifecycle
Solution Approach 2:
The patent implements feedback by using the ascertained changes in measurement data during transition from first to second surroundings to correct the original measurement data. This creates a closed-loop system where information about stress-induced warping feeds back into the measurement correction process, continuously improving placement accuracy predictions
2Reliability
If multilayer structure is applied to substrate, then reflective properties are improved, but internal stresses and warping increase
Solution Approach 1:
The patent applies preliminary action by measuring and recording the mask's state in first surroundings before operational use, capturing the initial flatness and placement data. By ascertaining changes during transition to second surroundings, the system can predict warping effects of the multilayer structure and compensate for them in advance, maintaining both reflective performance and shape accuracy
Solution Approach 2:
The patent implements feedback by using measurement data from first surroundings and changes ascertained during transition to correct for warping effects. This feedback loop allows the system to account for the multilayer structure's internal stresses and maintain mask flatness despite the inherent warping caused by the reflective coating
3Adaptability or versatility
If mask transitions from first to second surroundings, then operational use is enabled, but placement accuracy deteriorates due to stress changes
Solution Approach 1:
The patent applies preliminary action by determining measurement data in first surroundings and ascertaining changes during transition to second surroundings before operational use. This allows the system to pre-calculate correction values that will maintain pattern element placement accuracy despite environmental changes and internal stress variations
Solution Approach 2:
The patent implements feedback by using the ascertained changes during environmental transition to correct the original measurement data. This feedback mechanism enables the system to adapt to different surroundings while maintaining manufacturing precision, as the correction data compensates for stress-induced placement shifts
Data Source
AI summary
The present invention relates to a method for transforming measurement data of a photolithographic mask for the extreme ultraviolet (EUV) wavelength range from first surroundings into second surroundings. The method includes the steps of: (a) determining the measurement data for the photolithographic mask in the first surroundings, wherein the measurement data are influenced by the effects of internal stresses on the photolithographic mask; (b) ascertaining at least one change in the measurement data during the transition from the first surroundings into the second surroundings, in which change the effects of the internal stresses on the photolithographic mask are at least partly compensated; and (c) correcting the measurement data determined in step (a) with the at least one change in the measurement data ascertained in step (b).