Defect Classification Using Synthetic Templates

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Conventional learning-type classification methods for defect classification in semiconductor substrates require a large number of defect images, leading to suboptimal classification at the start of production and over-learning issues with small image datasets, making it difficult to accurately classify defects.

Innovation Solution

A defect classification method that creates defect templates and models by combining teaching images without defects with defect templates, calculating feature amounts, and setting classification classes, allowing for proper classification even with limited or no defect images by using these models and stored relations in a storage unit.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a large number of defect images are collected for learning-type classification, then defect classification accuracy is improved, but the system cannot properly classify defects at startup when defect images are unavailable

Engineering Contradiction:
Improvedefect classification accuracyVSAvoidstartup time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The system performs preliminary actions by creating defect templates and combining them with teaching images without defects to generate synthetic defect images before actual defect data is available. This preliminary model creation enables the classification system to function at startup without requiring collected defect images, thereby resolving the contradiction between needing accurate classification and having no defect images at startup

Inventive Principle:
Principle #10Preliminary action

2Productivity

If a small number of defect images are used for classification, then the system can operate with limited data, but over-learning occurs and classification accuracy deteriorates

Engineering Contradiction:
Improveclassification operation capabilityVSAvoiddefect classification accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The system creates copies of defect patterns through templates and combines them with teaching images to generate multiple synthetic defect images. This copying approach allows the system to operate with limited actual defect data while maintaining classification accuracy, as the synthetic images provide additional training samples without requiring collection of numerous real defect images

Inventive Principle:
Principle #26Copying

3Ease of operation

If conventional learning-type classification is used, then defect classification can be performed, but it requires collecting a large number of defect images which is time-consuming and impractical

Engineering Contradiction:
Improvedefect classification functionalityVSAvoidnumber of defect images required
Core Design Contradiction:
Ease of operationVSQuantity of substance

Solution Approach 1:

The system introduces an intermediary approach by using defect templates as a bridge between teaching images without defects and the final defect classification. Instead of directly requiring numerous real defect images, the templates serve as intermediaries that can be combined with available teaching images to create synthetic defect data, thereby enabling classification functionality without the need to collect large quantities of actual defect images

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentUS8379965B2Defect classification method, computer storage medium, and defect classification apparatus
Publication Date: 2013.02.19 TOKYO ELECTRON LTD
  • US8379965B2 patent drawing
  • US8379965B2 patent drawing
  • US8379965B2 patent drawing

AI summary

A defect classification apparatus of the present invention includes a design unit and a diagnosis unit. In the design unit, a model creation unit combines a defect template in a template storage unit with a teaching image to create a defect model, and a classification class setting unit calculates feature amounts of a defect in the defect model and sets a classification class of the defect. The relation between the feature amounts of the defect and the classification class is stored in a storage unit. In the diagnosis unit, a feature amount calculation unit calculates feature amounts of defects from a captured inspection object image of the substrate, and a classification unit classifies the defects of the substrate into classification classes from the relations between the feature amounts of the defects and the classification classes in the storage unit based on the calculated feature amounts of the defects.