Consistent Modulation for Semiconductor Defect Detection

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Solution Overview

Problem

Traditional defect detection methods in fabricated components, such as wafers, introduce inaccurate results due to the modulation of only the target component, leading to an overidentification of defects and difficulty in distinguishing actual defects from false positives.

Innovation Solution

Implementing consistent modulation between target and reference components, allowing for comparisons that generate more accurate defect detection by eliminating differences caused by modulation alone, and using a system that compares images of consistently modulated components to identify defects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If only the target component is modulated to amplify defects, then defect amplification is improved, but false-positive detections increase

Engineering Contradiction:

Improvedefect amplificationVSAvoidfalse-positive detections

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent applies parameter changes by modulating both the target component and reference components with the same modulation parameters (focus, exposure, dose). This transforms the comparison from detecting absolute differences to detecting relative differences, thereby amplifying defects while maintaining reliability by eliminating false positives caused by asymmetric modulation.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent inverts the traditional approach by making the reference components modulated instead of keeping them nominal. This inversion allows the modulation effects to be present in both target and reference, so that only actual defects create differences in the comparison, resolving the contradiction between defect amplification and false-positive reduction.

Inventive Principle:

Principle #13The other way round (Inversion)

2Measurement precision

If modulation is applied to target component, then defect visibility is improved, but differentiation between target and reference becomes inaccurate

Engineering Contradiction:

Improvedefect visibilityVSAvoidcomparison accuracy

Core Design Contradiction:

Measurement precisionVSManufacturing precision

Solution Approach 1:

The patent changes the modulation parameters of the reference components to match the target component's parameters. This ensures that both components experience the same optical conditions, making the comparison accurate while maintaining enhanced defect visibility through the modulation amplification.

Inventive Principle:

Principle #35Parameter changes

3Device complexity

If traditional defect detection methods are used, then inspection process is simple, but defect detection accuracy decreases

Engineering Contradiction:

Improveinspection process complexityVSAvoiddefect detection accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent modifies the inspection process by changing the modulation parameters of the reference components to match the target component. This parameter change improves defect detection accuracy by eliminating false positives, while the overall process remains relatively simple as it only requires adjusting the reference component parameters rather than fundamentally changing the inspection methodology.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS9940705B2System, method and computer program product for detecting defects in a fabricated target component using consistent modulation for the target and reference components

Publication Date: 2018.04.10 KLA CORP

AI summary

A fabricated device having consistent modulation between target and reference components is provided. The fabricated device includes a target component having a first modulation. The fabricated device further includes at least two reference components for the target component including a first reference component and a second reference component, where the first reference component and the second reference component each have the first modulation. Further, a system, method, and computer program product are provided for detecting defects in a fabricated target component using consistent modulation for the target and reference components.