Metrology Unit Integrated Reference Target for Automated System Checks
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Solution Overview
Problem
Current metrology systems require frequent interruptions for system checks, which interfere with the process cycle and reduce throughput, as they necessitate the loading and unloading of separate reference wafers to ensure measurement reliability and accuracy.
Innovation Solution
An integrated reference target is incorporated into the metrology unit, allowing for automated system checks without the need for a separate reference wafer, enabling continuous operation and minimizing interference with the production process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate reference wafers are loaded into the metrology unit for system checks, then measurement reliability is ensured, but the process cycle is interrupted and throughput is reduced
Solution Approach 1:
The reference target is merged with the production substrate to create an integrated reference target that contains both production features and reference features. This eliminates the need for separate reference wafers, allowing system checks to be performed on the same substrate being processed, thereby maintaining measurement reliability without interrupting the process cycle
Solution Approach 2:
The integrated reference target serves multiple functions: it acts as both a production substrate containing product features and a reference standard for system checks. This multi-functionality allows the metrology unit to perform both production measurement and system verification using the same substrate, eliminating throughput reduction
2Measurement precision
If separate reference wafers are loaded into the metrology unit for system checks, then measurement accuracy is verified, but downtime increases
Solution Approach 1:
The reference features are pre-integrated into the production substrate during manufacturing. This preliminary action ensures that reference data is already available on the substrate itself, eliminating the need to load separate reference wafers and reducing the time required for system checks while maintaining measurement accuracy verification
3Productivity
If an integrated reference target is used for automated system checks, then continuous operation is enabled, but system complexity increases
Solution Approach 1:
The integrated reference target is segmented into distinct production features and reference features, each serving specific functions. This segmentation allows the metrology unit to automatically distinguish between production measurement tasks and system check tasks, enabling continuous operation while managing system complexity through clear functional separation
Data Source
AI summary
A metrology unit includes an integrated reference target with which an automated system check process is performed. The automated system check process includes measuring a feature on the reference target and determining if the measurement is within a desired specification for the metrology unit. When the metrology unit fails the automated system check, or if otherwise warranted, an automated diagnosis process may be performed using the same integrated reference target. The automated system check and automated diagnosis may be optimized based on correlations between parameters of the automated qualification and parameters of the automated diagnosis. Similarly, the measurement of a processed wafer may be optimized based on a correlation between parameters of the metrology of the processed wafer and parameters of the automated system check.