Optical Scanner Signature Matching for Semiconductor Wafer Consistency
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Solution Overview
Problem
Scanners used in optical imaging of substrates produce pattern errors leading to inconsistencies in semiconductor wafers due to differences in imaging characteristics, necessitating a method to match and correct these characteristics for improved product consistency.
Innovation Solution
A method involving scanning a mask on two optical scanners to generate and compare 'signature characteristics' such as line widths, line gaps, and pitch, allowing for the adjustment of scanner features to match or control the imaging performance, using aerial image sensing systems to maximize sensitivity and consistency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If scanners operate with high numerical aperture for improved imaging resolution, then imaging precision is improved, but manufacturing precision deteriorates due to pattern errors and inconsistencies between different scanners
Solution Approach 1:
The patent applies parameter changes by systematically varying scanner operating parameters (such as focus, exposure, and alignment settings) and using statistical analysis to identify and correct deviations in signature characteristics. This allows high numerical aperture operation while compensating for parameter variations that cause pattern inconsistencies across different scanners
Solution Approach 2:
The patent implements feedback through the collection and analysis of signature characteristics from multiple scanners, comparing measured values against target values, and using this information to adjust scanner settings. This closed-loop approach maintains both high imaging resolution and consistent manufacturing precision across the scanner fleet
2Productivity
If multiple scanners are used to increase productivity, then output is improved, but manufacturing precision deteriorates due to variations in imaging characteristics between scanners
Solution Approach 1:
The patent creates a universal matching framework that can be applied across multiple scanners with different configurations. By establishing common signature characteristics and target values that multiple scanners can achieve through parameter adjustment, the system enables consistent manufacturing precision across the entire scanner fleet while maintaining high productivity through parallel operation of multiple tools
Solution Approach 2:
The patent systematically adjusts operating parameters of each scanner based on its measured signature characteristics to match target values. This parameter optimization process enables multiple scanners to produce consistent patterns despite hardware variations, allowing the facility to operate multiple tools simultaneously for high productivity while maintaining uniform manufacturing precision
Data Source
AI summary
A method for matching characterizing features of an optical scanner against target characterizing features is provided. The characterizing features are produced from characterizing data (also referred to as a signature characteristic) produced from a scan of a mask by the scanner against target scanner signature characteristics produced from a scan of the mask by another optical scanner that produces the target scanner signature characteristic.