Image modeling-assisted metrology
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Solution Overview
Problem
Current metrology methods in semiconductor manufacturing are limited by imaging resolution, requiring destructive measurements and are slow, inaccurate, and unable to measure buried layers effectively.
Innovation Solution
An imaging subsystem and computer subsystem are used to generate and compare images of a specimen with different modes, optimizing quality metrics to determine patterned feature characteristics accurately, including those below the surface, using image modeling to account for imaging conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high resolution images are used to measure patterned feature characteristics, then measurement precision is improved, but imaging time increases and productivity decreases
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing rendered images for multiple patterned feature characteristic values before actual measurement. During measurement, the system compares captured images against these pre-generated rendered images to quickly determine characteristics without performing complex real-time rendering, thus achieving high precision while maintaining productivity.
Solution Approach 2:
The patent uses copying by creating rendered images that replicate the appearance of actual specimen images. These rendered images are generated from design data and imaging model parameters, serving as virtual copies that can be rapidly compared against captured images to determine patterned feature characteristics without requiring high-resolution capture for every measurement scenario.
2Measurement precision
If destructive measurement methods are used to measure buried layers, then measurement precision is improved, but the specimen is damaged and cannot be reused
Solution Approach 1:
The patent employs copying by generating rendered images from design data that replicate the appearance of buried patterned features without physically accessing or damaging the specimen. These virtual rendered images are compared against captured images to measure characteristics of buried layers, eliminating the need for destructive sectioning or TEM analysis while maintaining measurement precision.
Solution Approach 2:
The patent introduces an intermediary approach by using rendered images as a mediator between the captured images and the measurement results. The rendered images serve as a virtual reference that enables measurement of buried features through image comparison algorithms, avoiding direct physical interference with the specimen and allowing non-destructive measurement.
3Measurement precision
If multiple imaging modes are used to improve measurement accuracy, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent applies universality by developing a single integrated imaging system capable of capturing images in multiple modes (e.g., different focus planes, illumination conditions, or resolution levels). The system uses a unified image comparison algorithm that processes all captured images regardless of mode, allowing one device to perform multiple measurement functions that would traditionally require separate specialized instruments.
Solution Approach 2:
The patent merges multiple imaging modes and measurement functions into a single integrated system. Instead of using separate instruments for different measurement tasks, the system combines multiple capture modes within one device and processes all images through a unified algorithm framework, reducing overall device complexity while maintaining enhanced measurement precision through multi-mode data analysis.
Data Source
AI summary
Methods and systems for determining characteristic(s) of patterned feature(s) on a specimen are provided. One system includes a computer subsystem configured for comparing one or more images of a specimen generated by an imaging subsystem with one or more modes, respectively, to rendered images generated for the one or more modes and at least one instance of a design for the specimen corresponding to at least one of different values of at least one characteristic of one or more patterned features in the design. The computer subsystem is also configured for determining one or more quality merits for results of the comparing and optimizing the one or more quality merits using an optimization method. In addition, the computer subsystem is configured for determining characteristic(s) of the patterned feature(s) on the specimen from results of the optimizing.