Reticle Fabrication Using Contour Overlay Analysis for EUV Defect Reduction
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Solution Overview
Problem
Current semiconductor device fabrication methods face challenges in minimizing defects, particularly due to shot noise from extreme ultraviolet (EUV) light sources, which result in high dispersion and low uniformity in photolithography patterns, affecting the accuracy and quality of semiconductor devices.
Innovation Solution
A reticle fabrication method that involves performing a photolithography process on a test substrate using a first reticle, measuring the substrate to obtain images, designing a second reticle with redesigned patterns based on the margin of the photolithography process, and manufacturing the second reticle, where contour images are analyzed to determine defects by comparing overlay values with reference values, and rearranging patterns to minimize or eliminate defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If EUV light source is used for photolithography, then integration capability is improved, but shot noise causes high dispersion and low uniformity in patterns
Solution Approach 1:
The patent applies preliminary action by measuring test substrates and analyzing contour overlay values before mass production. The method performs photolithography on test substrates, measures the results, and uses the measured images to determine whether defects are present in the reticle patterns. This preliminary measurement and analysis step allows defects to be detected and corrected before full-scale manufacturing, thereby improving pattern uniformity while maintaining the integration capabilities enabled by EUV light sources.
2Device complexity
If reticle patterns are designed without margin consideration, then manufacturing complexity is reduced, but photolithography process variability causes defects
Solution Approach 1:
The patent implements feedback by measuring test substrates and using the measured images to determine defect presence in reticle patterns. The method creates a feedback loop where measurement results inform subsequent manufacturing decisions. Specifically, the system measures test substrates, analyzes contour overlay values, and uses this information to determine whether defects are present, allowing for continuous improvement and correction of reticle design and manufacturing processes.
Solution Approach 2:
The patent applies preliminary action by performing photolithography on test substrates and measuring them before mass production. This preliminary testing phase allows the manufacturing process to identify potential defects and adjust parameters accordingly. The method measures test substrates, analyzes the measured images, and determines defect presence before full-scale manufacturing begins, thereby reducing the defect rate without significantly increasing reticle design complexity.
3Measurement precision
If contour overlay measurement is performed with high precision, then defect detection accuracy is improved, but measurement and analysis time increases
Solution Approach 1:
The patent applies the taking out principle by extracting and analyzing only the critical contour overlay information from measured images rather than performing comprehensive analysis of all image data. The method specifically extracts contour images and calculates contour overlay values, focusing measurement efforts on the most relevant features for defect detection. This selective extraction approach maintains high defect detection accuracy while reducing the overall measurement and analysis time required.
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
This method effectively reduces defects in semiconductor devices by improving the uniformity and accuracy of photolithography patterns, enhancing the overall quality and reliability of semiconductor fabrication.
Implementation Method 1
performing a photolithography process on a test substrate using a first reticle having first patterns
Data Source
AI summary
Disclosed are reticle fabrication methods and semiconductor device fabrication methods. The reticle fabrication method includes performing a photolithography process on a test substrate using a first reticle having first patterns, measuring the test substrate to obtain measured images, designing a second reticle having second patterns, redesigning the second reticle based on a margin of the photolithography process, and manufacturing the redesigned second reticle. Redesigning the second reticle includes obtaining sample images from the measured images when the first patterns are the same as the second patterns, obtaining contour images that have contours of sample patterns in the sample images, overlapping the contours to obtain a contour overlay value, and comparing the contour overlay value with a reference value to determine defects of the second patterns.