Pattern Measurement Equipment Template Segmentation

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Solution Overview

Problem

Existing pattern measurement techniques using charged particle beam apparatuses face challenges in accurately matching CAD data with SEM images due to shape differences and magnification errors, especially when multiple patterns are involved, leading to inaccuracies in dimension measurement.

Innovation Solution

The method involves selective pattern matching by targeting specific regions of the design data and performing multiple matching processes to isolate and correct for shape and magnification errors, using correlation operations and pixel-based comparisons to achieve precise alignment between CAD data and SEM images.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If pattern matching is performed using all patterns in the template including multiple patterns from CAD data, then the matching process can cover the entire design region, but shape differences and magnification errors cause inaccuracies in dimension measurement

Engineering Contradiction:

Improvedimension measurement accuracyVSAvoidmatching accuracy

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent segments the template into multiple individual patterns and performs matching separately for each pattern rather than treating the entire template as a single unit. This segmentation allows the system to identify and exclude patterns that exhibit shape differences or magnification errors, thereby preventing these errors from affecting the overall dimension measurement accuracy.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies different quality criteria to different patterns within the template. By evaluating each pattern's matching results individually, the system can identify patterns with local quality issues (shape differences, magnification errors) and selectively exclude them from the final measurement calculation, while maintaining high accuracy for patterns that meet the quality criteria.

Inventive Principle:

Principle #3Local quality

2Productivity

If a template based on CAD data is used for matching, then the measurement process can be automated and efficient, but magnification errors occur when the template includes multiple patterns

Engineering Contradiction:

Improvemeasurement efficiencyVSAvoiddimensional accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The patent implements a feedback mechanism where the matching results of individual patterns are evaluated and used to adjust the selection of patterns for final measurement calculation. The system feeds back information about pattern quality (presence of shape differences or magnification errors) and automatically adjusts which patterns contribute to the dimension measurement, thereby maintaining both efficiency and accuracy.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent changes the parameter of pattern selection dynamically based on matching quality assessment. Rather than using a fixed set of all patterns, the system adjusts which patterns are included in the final measurement by changing the selection parameter based on detected errors, thus maintaining measurement precision while preserving automated efficiency.

Inventive Principle:

Principle #35Parameter changes

3Area of stationary object

If all patterns in the template are used for matching, then comprehensive coverage of the design data is achieved, but shape differences between CAD patterns and SEM image patterns reduce matching reliability

Engineering Contradiction:

Improvecoverage areaVSAvoidmatching reliability

Core Design Contradiction:

Area of stationary objectVSReliability

Solution Approach 1:

The patent segments the template into multiple individual patterns and evaluates each separately. This segmentation enables the system to achieve comprehensive coverage by including multiple patterns while simultaneously maintaining reliability by excluding specific patterns that exhibit shape differences, thus resolving the contradiction between coverage and reliability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies partial action by selectively using only the reliable subset of patterns for final dimension measurement rather than all patterns. By performing excessive matching evaluation on all patterns first and then selecting only the reliable ones for the final calculation, the system achieves both comprehensive coverage and high matching reliability.

Inventive Principle:

Principle #16Partial or excessive action

Data Source

PatentUS8295584B2Pattern measurement methods and pattern measurement equipment

Publication Date: 2012.10.23 HITACHI HIGH TECH CORP

AI summary

An object of the present invention is to provide methods and equipment capable of providing highly accurate matching using a template including multiple patterns even when the shapes of some patterns of the template are different from corresponding ones of a SEM image, and when the template and the SEM image have a magnification error. Proposed, as a technique for achieving the object, is a method for performing matching by selectively using some of multiple patterns provided in a predetermined region of design data, and equipment for implementing the method. Moreover, proposed, as another technique for achieving the object, is a method for performing first matching by using multiple patterns provided in a predetermined region of design data and thereafter performing second matching by using some of the multiple patterns provided in the predetermined region, and equipment for implementing the method.