Unified Stochastic Variation Measurement for Semiconductor Patterns

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Solution Overview

Problem

Current methods lack a unified solution for measuring stochastic variations in both 1D and 2D patterns with the same algorithm, leading to inconsistent and inefficient measurement of stochastic edge placement error (SEPE) across different SEM machines, which hinders accurate modeling and optimization of patterning processes in semiconductor manufacturing.

Innovation Solution

A method that extracts high-quality composite contours from averaged images to guide contour extraction from raw images, allowing for unified measurement of stochastic variations in both 1D and 2D patterns, enabling accurate sub-pixel alignment and statistical analysis to determine process variations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If different measurement algorithms are used for 1D and 2D patterns, then measurement can be performed on both pattern types, but measurement consistency and efficiency deteriorate due to lack of unified solution

Engineering Contradiction:
Improvemeasurement capability for different pattern typesVSAvoidmeasurement efficiency
Core Design Contradiction:
Adaptability or versatilityVSProductivity

Solution Approach 1:

The patent implements a unified measurement algorithm that can handle both 1D and 2D patterns using the same processing steps. The method extracts contours from raw SEM images and calculates SEPE measurements through a single standardized procedure that adapts to different pattern geometries, eliminating the need for separate algorithms for different pattern types while maintaining measurement consistency across all pattern configurations.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Measurement precision

If multiple separate algorithms are used for different pattern types, then each algorithm can be optimized for its specific pattern, but measurement consistency across different SEM machines deteriorates

Engineering Contradiction:
Improvealgorithm optimization for specific patternsVSAvoidmeasurement consistency across machines
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent applies homogeneous processing steps across all pattern types, using identical contour extraction and SEPE calculation methods for both 1D and 2D patterns. This uniform approach ensures that measurements are performed consistently across different SEM machines and pattern types, improving inter-machine measurement reliability while maintaining adequate precision through the standardized procedure.

Inventive Principle:
Principle #33Homogeneity

3Measurement precision

If complex separate algorithms are used for 1D and 2D patterns, then accurate measurement can be achieved for each pattern type, but device complexity increases

Engineering Contradiction:
Improvemeasurement accuracy for specific patternsVSAvoidalgorithm complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent employs a single unified algorithm that performs both 1D and 2D pattern measurements through the same processing steps. The method extracts contours from raw images and calculates SEPE measurements using consistent mathematical operations that work for any pattern geometry, thereby reducing overall algorithmic complexity while maintaining measurement accuracy across different pattern types.

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Adaptability or versatility

If multiple measurement algorithms are implemented, then comprehensive pattern coverage is achieved, but ease of operation deteriorates due to algorithm selection complexity

Engineering Contradiction:
Improvepattern measurement coverageVSAvoidalgorithm selection simplicity
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The patent implements a single universal measurement algorithm that automatically handles both 1D and 2D patterns without requiring user selection or configuration. The unified approach processes all pattern types through the same contour extraction and SEPE calculation steps, eliminating algorithm selection complexity and improving ease of operation while maintaining comprehensive pattern measurement coverage.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentUS11567413B2Method for determining stochastic variation of printed patterns
Publication Date: 2023.01.31 ASML NETHERLANDS BV
  • US11567413B2 patent drawing
  • US11567413B2 patent drawing
  • US11567413B2 patent drawing

AI summary

A method for determining measurement data of a printed pattern on a substrate. The method involves obtaining (i) images of the substrate including a printed pattern corresponding to a reference pattern, (ii) an averaged image of the images, and (iii) a composite contour based on the averaged image. Further, the composite contour is aligned with respect to a reference contour of the reference pattern and contours are extracted from the images based on both the aligned composite contour and the output of die-to-database alignment of the composite contour. Further, the method determines a plurality of pattern measurements based on the contours and the measurement data corresponding to the printed patterns based on the plurality of the pattern measurements. Further, the method determines a one or more process variations such as stochastic variation, inter-die variation, intra-die variation and/or total variation.