Chip Surface Structure Measurement Using 2D Image Conversion
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Solution Overview
Problem
Current critical dimension scanning electron microscopes (CD-SEM) are slow and limited in obtaining real-time data for nano-generation semiconductor chips, primarily capable of measuring 1D images, making it difficult to assess surface structure and defect information like critical dimension uniformity (CDU) effectively.
Innovation Solution
A method using instruments like CD-SEM, E-Beam inspection tools, and image processing techniques to extract 2D image data from chip surfaces, converting images into circuit design files for comparison, enabling real-time analysis of line edge roughness, line width roughness, contact edge roughness, and critical dimension uniformity without requiring a model for dose map correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If CD-SEM is used for line width measurement and surface structure analysis, then measurement precision is improved, but inspection speed deteriorates (extremely slow)
Solution Approach 1:
The patent segments the inspection process into two stages: first, a low-magnification overview scan to identify potential defect regions across the entire chip; second, high-magnification detailed inspection only in those identified regions. This segmentation allows the system to maintain high measurement precision where needed while dramatically improving overall inspection speed by avoiding exhaustive high-mag scanning of the entire chip.
Solution Approach 2:
The patent applies partial action by performing comprehensive high-precision measurement only on selected defect regions rather than the entire chip surface. The overview scan covers 100% of the chip area at low magnification, but detailed high-mag inspection is applied partially only to regions showing anomalies, thus achieving high precision where necessary while maintaining fast overall throughput.
2Measurement precision
If CD-SEM obtains data of 1D image, then measurement capability is improved, but 2D surface structure analysis capability deteriorates (can only calculate CER of circular contact through specific software)
Solution Approach 1:
The patent transitions from traditional 1D line profile analysis to comprehensive 2D surface structure analysis by capturing and processing images at multiple magnification levels. The system extracts dimensional information from 2D images, enabling analysis of line edge roughness, line width roughness, contact edge roughness, and critical dimension uniformity across the entire chip surface, not just linear contacts.
Solution Approach 2:
The patent creates a universal measurement system that can analyze multiple types of surface structures (lines, contacts, patterns of various geometries) using the same 2D image processing framework. The system automatically adapts to different pattern types and calculates appropriate metrics (LER, LWR, CER, CDU) without requiring specialized software for each geometry type, thus achieving multi-functional versatility.
3Measurement precision
If traditional CD-SEM inspection is used, then measurement accuracy is improved, but time consumption deteriorates (impossible to obtain many inspection results in real-time)
Solution Approach 1:
The patent performs preliminary low-magnification scanning of the entire chip surface before detailed high-magnification inspection. This preliminary action identifies defect regions that require detailed analysis, allowing the system to skip time-consuming high-mag scanning in defect-free areas and focus computational and measurement resources only where anomalies are detected, thus reducing overall inspection time while maintaining accuracy.
Solution Approach 2:
The patent implements a skip strategy by rapidly scanning large areas at low magnification to identify regions of interest, then rushing through the time-consuming high-precision measurement process only in those selected regions. This approach skips unnecessary detailed inspection in known-good areas, enabling real-time inspection results across multiple chips while preserving measurement accuracy where needed.
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
Enables accurate, real-time measurement and analysis of 2D surface structures and defect information across entire chips, significantly improving the speed and accuracy of defect detection and dose map correction, replacing traditional lengthy analysis procedures.
Implementation Method 1
using an E-Beam inspection tool to obtain an image of the surface structure
Data Source
AI summary
A method for measuring a surface structure of a chip or a wafer is provided that includes obtaining an image of the surface structure of the chip, and then performing an image extraction on the image to convert the extracted image into a first circuit design file. A standard image is selected to convert into a second circuit design file, and then the standard image and at least one target in the image are compared to obtain a difference therebetween. According to the difference, at least one data of the surface structure may be made, wherein the data is selected from one of line edge roughness (LER), line width roughness (LWR), contact edge roughness (CER), critical dimension (CD), bias, 3 sigma, maximum, minimum, etc. and repeating defect.