Exposure System Distortion Profile Database for Alignment Optimization
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Solution Overview
Problem
Current methods for optimizing alignment performance in fleets of exposure tools in semiconductor fabrication are labor-intensive, time-consuming, and prone to errors, leading to inefficiencies and costly idling of expensive equipment due to intrinsic pattern placement errors and misalignments across different tools.
Innovation Solution
Characterizing each exposure system to generate distinctive distortion profiles, which are stored in a database for real-time adjustments and updates using metrology information from production wafers, enabling the selection of the best-fit exposure system for each layer and real-time parameter adjustments to minimize alignment errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional calibration methods are used to ensure exposure systems meet manufacturer specifications, then manufacturing precision is improved, but alignment errors and misalignments still exist due to intrinsic tool variations
Solution Approach 1:
The patent applies parameter changes by adjusting distortion correction parameters for each exposure system based on its unique error signature. Each tool is calibrated with specific correction parameters stored in a database, allowing the system to compensate for intrinsic variations and achieve consistent alignment across the fleet.
Solution Approach 2:
The patent implements feedback mechanisms where metrology tools continuously measure alignment performance, and this information feeds back to update distortion profiles in the database. This enables real-time optimization of alignment parameters to maintain precision despite tool variations.
2Manufacturing precision
If exposure systems are grouped by similar error propagation properties to maintain alignment, then manufacturing precision is improved, but productivity decreases due to equipment idling when tools are unavailable
Solution Approach 1:
The patent applies dynamics by enabling flexible, real-time selection of exposure systems based on current availability and performance state. The system dynamically assigns tools to production tasks considering both precision requirements and tool availability, preventing idle time when specific tools are occupied or undergoing maintenance.
Solution Approach 2:
The system changes operational parameters by adjusting distortion correction parameters for different tools based on their specific error signatures. This allows any available tool to be effectively used for alignment-critical tasks by applying the appropriate correction parameters, maximizing fleet utilization while maintaining precision.
3Manufacturing precision
If distortion correction parameters are adjusted for each exposure system, then manufacturing precision is improved, but device complexity increases due to multiple adjustment features and degrees of freedom
Solution Approach 1:
The patent applies copying by creating a database of distortion profiles that captures the error signatures of multiple exposure systems. Instead of managing complex real-time adjustments for each tool, the system stores pre-characterized distortion parameters and retrieves the appropriate profile during operation, simplifying the control approach while maintaining high precision.
Solution Approach 2:
The patent implements preliminary action by pre-characterizing each exposure system's distortion properties during initial calibration and storing these parameters in the database. This advance preparation eliminates the need for complex real-time analysis and adjustment, reducing control system complexity while ensuring accurate pattern placement.
4Manufacturing precision
If metrology tools are used to measure and quantify errors in each exposure system, then manufacturing precision is improved, but loss of time increases due to calibration and characterization processes
Solution Approach 1:
The patent applies preliminary action by performing comprehensive distortion characterization and error quantification during initial tool setup and calibration. These time-consuming measurements are completed once and stored in the database, eliminating the need for repeated time-consuming metrology processes during production and minimizing time loss.
Solution Approach 2:
The system implements self-service by enabling automatic retrieval and application of distortion correction parameters from the database during production operations. This eliminates the need for continuous manual intervention and time-consuming real-time metrology measurements, allowing the system to self-optimize alignment based on pre-stored characterization data.
Data Source
AI summary
A method for optimizing alignment performance in a fleet of exposure systems involves characterizing each exposure system in a fleet of exposure systems to generate a set of distinctive distortion profiles associated with each exposure system. The set of distinctive distortion profiles are stored in a database. A wafer having reference pattern formed thereon is provided for further pattern fabrication and an exposure system is selected from the fleet to fabricate a next layer on the wafer. Linear and higher order parameters of the selected exposure system are adjusted using the distinctive distortion profiles to model the distortion of the reference pattern. Once the exposure system is adjusted, it is used to form a lithographic pattern on the wafer.