Mask Inspection Pre-Check for Lithography Downtime Reduction
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Solution Overview
Problem
The existing lithographic apparatuses face significant downtime and inefficiencies due to scanning issues during mask inspections, which require extensive recovery times and can lead to production line stops.
Innovation Solution
An inline pre-warning system is introduced to ensure inspection apparatus reliability by conducting a pre-checking procedure before mask inspections. This system checks parameters such as mask leveling and laser health, and implements auto-recovery mechanisms to adjust for fluctuations, ensuring consistent quality in the inspection process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional mask inspection is performed without pre-checking, then the inspection process is simpler, but scanning issues occur causing extended downtime and production line stops
Solution Approach 1:
The patent implements a pre-checking procedure that executes before the main mask inspection to detect potential scanning issues. This preliminary action identifies problems with mask leveling, laser health, and other parameters before they cause scan fails, thereby improving reliability without significantly complicating the overall inspection workflow.
Solution Approach 2:
The system incorporates feedback mechanisms where inspection parameters are monitored and compared against reference values. When deviations are detected, the system automatically adjusts parameters or triggers recovery procedures, creating a closed-loop control system that enhances reliability while maintaining manageable complexity through automated decision-making.
2Productivity
If manual recovery procedures are used for scan fails, then the system is easier to control, but recovery time increases significantly causing production losses
Solution Approach 1:
The patent implements auto-recovery mechanisms that enable the inspection apparatus to self-correct scanning issues without manual intervention. The system automatically detects scan fails, identifies root causes through parameter comparison, and executes recovery procedures such as adjusting mask leveling or laser parameters, thereby restoring productivity while managing complexity through automation.
Solution Approach 2:
By performing pre-checking procedures before main inspection, the system proactively identifies potential scanning issues and executes recovery actions before they cause production stoppages. This preliminary detection and correction approach minimizes downtime and maximizes tool availability.
3Manufacturing precision
If inspection parameters are not adjusted for fluctuations, then the inspection process is more stable, but quality consistency deteriorates
Solution Approach 1:
The system continuously monitors inspection parameters such as mask leveling and laser health, comparing them against reference values. When fluctuations exceed acceptable thresholds, the system automatically adjusts parameters to maintain quality consistency. This feedback-driven approach ensures manufacturing precision while managing complexity through automated control algorithms.
Solution Approach 2:
The patent dynamically adjusts inspection parameters based on detected fluctuations and comparisons with reference images. By changing parameters such as focus, illumination intensity, or scan speed in response to measured variations, the system maintains consistent inspection quality despite environmental or equipment 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
The inline pre-warning system minimizes downtime and enhances tool availability by detecting potential issues before they cause scan fails, thereby preventing production halts and reducing recovery time.
Implementation Method 1
measuring a first reflected light intensity from the first reference image; measuring a second reflected light intensity on the mask
Data Source
AI summary
A method includes capturing a first reference image of a mask by an inspection apparatus, the capturing comprising measuring a first reflected light intensity from the first reference image; performing, using the mask, an exposure process on a wafer; after performing the exposure process, measuring a second reflected light intensity on the mask by the inspection apparatus; comparing the second reflected light intensity with the first reflected light intensity from the first reference image; determining whether a first comparison result of the first and second reflected light intensities is acceptable; in response to the determination determines that the first comparison result is unacceptable, adjusting an inspection parameter of the inspection apparatus.