Dynamic Pupil Compensation in Lithography for Pattern Shift Control
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Solution Overview
Problem
Current methods for mitigating Mask 3D effects in lithographic apparatuses fail to account for dynamic pupil interactions, leading to pattern shifts and degradation of features on the substrate due to dynamic pupil variations during exposure.
Innovation Solution
A method and apparatus that determine a dynamic pupil's angular distribution during scanning, adjust mask and lithographic apparatus parameters to minimize pattern shifts by configuring reticle stage tilt, illumination source, projection lens, and wafer stage movements to compensate for dynamic pupil interactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If current lithographic techniques assume a stationary illumination source, then the patterning process is simplified and easier to control, but the imaging quality degrades when the illumination source varies during exposure due to dynamic pupil interactions
Solution Approach 1:
The patent applies the dynamics principle by transitioning from a static illumination model to a dynamic pupil model that accounts for temporal variations during exposure. The system captures pupil evolution over time and uses this dynamic information to calculate and compensate for pattern placement shifts, thereby maintaining accuracy despite source variations during the scanning operation
Solution Approach 2:
The patent implements preliminary action by measuring and characterizing the dynamic pupil behavior before performing the actual patterning compensation. The system pre-captures pupil evolution data and pre-calculates compensation parameters that are then applied during exposure, allowing the system to proactively correct for anticipated pattern shifts rather than reacting to them
2Productivity
If the illumination source is allowed to vary during exposure, then the scanning operation can proceed at normal speed, but pattern shifts and fading effects occur leading to degradation of feature quality
Solution Approach 1:
The patent applies feedback by using the measured dynamic pupil information to continuously adjust and compensate for pattern placement errors. The system captures pupil evolution during scanning, calculates the resulting pattern shifts, and applies compensation parameters to correct these shifts, creating a closed-loop system that maintains feature quality despite high-speed scanning operations
3Device complexity
If current M3D effect correction methods use an average pupil model, then the correction process is computationally simpler, but the interaction between dynamic pupil and M3D effects is disregarded causing erroneous pattern printing
Solution Approach 1:
The patent applies segmentation by dividing the continuous pupil evolution into discrete temporal snapshots or frames during the exposure process. Instead of using a single average pupil model, the system segments the pupil data into multiple time-points, analyzes the evolution pattern, and uses this segmented dynamic information to calculate more accurate compensation parameters for pattern placement
Data Source
AI summary
A method for improving imaging of a feature on a mask to a substrate during scanning operation of a lithographic apparatus. The method includes obtaining a dynamic pupil representing evolution of an angular distribution of radiation exposing a mask during a scanning operation of a lithographic apparatus and determining a variation of shift of a feature at a substrate during the scanning operation due to interaction of the dynamic pupil with the mask. The method includes configuring a mask parameter and/or or a control parameter of the lithographic apparatus to reduce the variation of shift of the feature.