EUV Dose Correction Map for Flare Compensation
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Solution Overview
Problem
The high flare (scattered light) of EUV light in semiconductor lithography leads to undesirable pattern dimension fluctuations exceeding tolerance ranges, which existing methods fail to adequately correct, especially when using EUV light with a wavelength of 13.5 nm, where flare intensity is significantly higher than with ArF light.
Innovation Solution
A method for creating a correction map of the dose amount of EUV light that iteratively adjusts the exposure based on initial correction maps, considering both the flare of the region's own shot and adjacent shots, to achieve stable and precise pattern formation by refining the dose distribution through the exposure apparatus's optical path.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If EUV light is used for lithography, then shorter wavelength enables higher resolution, but flare intensity increases significantly
Solution Approach 1:
The patent applies preliminary action by creating a correction map before actual lithography to compensate for flare effects. The correction map is generated through simulation that predicts flare distribution, and this pre-calculated correction data is then applied during exposure to counteract the harmful flare effects before they manifest in the final pattern.
Solution Approach 2:
The patent converts the harmful flare effect into a beneficial correction opportunity. By simulating and mapping the flare distribution in advance, the system transforms the unpredictable harmful effect into a predictable pattern that can be compensated for through dose adjustment, effectively turning the flare problem into a solvable correction task.
2Manufacturing precision
If conventional correction methods are used, then processing time is reduced, but pattern dimension control becomes inadequate
Solution Approach 1:
The correction map is generated in advance through simulation before actual lithography production. This preliminary correction data preparation allows the actual exposure process to proceed efficiently without real-time complex calculations, while still achieving high precision through the pre-computed correction values.
Solution Approach 2:
The patent creates a virtual model (correction map) that copies and represents the flare effect characteristics. This correction map serves as a simplified representation of the complex flare phenomenon, allowing the system to work with corrected dose values without directly handling the complex physical flare effects during production.
3Stability of the object's composition
If dose correction is applied, then exposure uniformity improves, but calculation complexity increases
Solution Approach 1:
The complex dose correction calculations are performed in advance to generate the correction map. This preliminary computation phase handles the mathematical complexity, while the actual exposure process simply applies the pre-calculated correction values, maintaining exposure uniformity without real-time computational burden.
Data Source
AI summary
According to one embodiment, a method for making a correction map of a dose amount of EUV light used when exposing with the EUV light, includes estimating an exposure result based on an initial correction map of the dose amount and flare of the EUV light, determining a goodness of the exposure result, and correcting the initial correction map in the case where the exposure result is unacceptable. And, the correcting of the initial correction map, the estimating of the exposure result, and the determining of the goodness are repeated until the exposure result is good.