SEM Pattern Matching with Candidate Edge Selection Control

Solution Overview

Problem

Existing pattern matching technologies struggle with accurately selecting edge candidates in SEM images with weak edges, leading to unstable matching and prolonged processing times, particularly in multilayer patterns.

Innovation Solution

A pattern matching apparatus that includes a computer system for executing pattern matching between design data and SEM images, using edge candidate selection and association evaluation to identify and stabilize edge candidates, minimizing the number of candidates to enhance accuracy and efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If threshold processing is used to select edge candidates, then processing time is reduced, but true edges may be failed to be extracted when edges are weak

Engineering Contradiction:

Improveprocessing timeVSAvoidedge extraction accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The patent applies preliminary action by performing association processing between edge candidates from design data and SEM image data before final edge selection. This preliminary association step identifies likely true edges based on spatial and contextual relationships, allowing subsequent threshold processing to focus on a refined set of candidates rather than all possible edges, thus maintaining accuracy while reducing processing time.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent introduces an intermediary mechanism through the use of association evaluation values that mediate between raw edge detection and final edge selection. These evaluation values serve as an intermediate representation that captures the likelihood of an edge being a true edge based on multiple factors including spatial position, intensity, and association with design data, enabling more accurate selection without requiring aggressive thresholding.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If all edge candidates are selected without threshold processing, then true edges are not missed, but processing time becomes long and matching becomes unstable

Engineering Contradiction:

Improveedge extraction accuracyVSAvoidprocessing time

Core Design Contradiction:

Measurement precisionVSProductivity

Solution Approach 1:

The patent applies the taking out principle by extracting and selecting only the necessary number of edge candidates (selection-required number) from the complete set of detected edges. This selective extraction is performed based on association evaluation values that rank candidates by their likelihood of being true edges, allowing the system to work with a manageable subset of high-probability candidates rather than processing all detected edges, thus reducing processing time while maintaining accuracy.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent applies parameter changes by dynamically adjusting the number of edge candidates to be processed based on the selection-required number calculation. Instead of using a fixed threshold or processing all edges, the system changes the parameter of candidate count to match the actual needs of the matching task, optimizing the balance between processing time and matching stability for each specific case.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If the number of edge candidates is large, then comprehensive coverage is achieved, but association processing time increases and matching stability decreases

Engineering Contradiction:

Improvematching stabilityVSAvoidassociation processing time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent applies preliminary action by performing association processing between edge candidates from design data and SEM image data before final edge selection. This preliminary association step identifies likely true edges based on spatial and contextual relationships, allowing subsequent threshold processing to focus on a refined set of candidates rather than all possible edges, thus maintaining accuracy while reducing processing time.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent applies parameter changes by dynamically adjusting the number of edge candidates to be processed based on the selection-required number calculation. Instead of using a fixed threshold or processing all edges, the system changes the parameter of candidate count to match the actual needs of the matching task, optimizing the balance between processing time and matching stability for each specific case.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS12412275B2Pattern matching device, pattern measurement system, and non-transitory computer-readable medium

Publication Date: 2025.09.09 HITACHI HIGH TECH CORP

AI summary

A pattern matching apparatus includes a computer system configured to execute pattern matching processing between first pattern data based on design data and second pattern data representing a captured image of an electron microscope. The computer system acquires a first edge candidate group including one or more first edge candidates, acquires a selection-required number (the number of second edge candidates to be selected based on the second pattern data), acquires a second edge candidate group including the second edge candidates of the selection-required number, acquires an association evaluation value for each of different association combinations between the first edge candidate group and the second edge candidate group, selects one of the combinations based on the association evaluation value, and calculates a matching shift amount based on the selected combination.