Pattern Determination Device for SEM Wafer Inspection

Solution Overview

Problem

In scanning electron microscopes, distinguishing between line and space patterns with similar widths is challenging, especially when contrast is low, and existing methods for obtaining three-dimensional information require beam inclining, which reduces throughput.

Innovation Solution

A device and computer program that classify regions based on profile waveforms to determine concave or convex portions and gaps, using area thresholds and statistical tests to differentiate between them, allowing for stable identification of unevenness and gap measurements without beam inclination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If beam inclining is performed to obtain three-dimensional information, then unevenness information can be obtained, but throughput lowers and processing time increases

Engineering Contradiction:

Improvethree-dimensional informationVSAvoidthroughput

Core Design Contradiction:

Measurement precisionVSProductivity

Solution Approach 1:

The patent creates a virtual three-dimensional model by copying and processing two-dimensional image data through stereo matching algorithms, eliminating the need for physical beam inclining while still obtaining three-dimensional unevenness information

Inventive Principle:

Principle #26Copying

Solution Approach 2:

The patent replaces the mechanical beam inclining system with an image processing system that uses computational algorithms to extract three-dimensional information from two-dimensional images, substituting mechanical action with information processing

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If beam inclining is performed to obtain three-dimensional information, then unevenness information can be obtained, but processing time is needed for performing beam inclining

Engineering Contradiction:

Improvethree-dimensional informationVSAvoidprocessing time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent performs preliminary stereo matching and three-dimensional model construction during the image acquisition phase, so that unevenness information is already prepared and available without requiring additional processing time later

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent creates a virtual three-dimensional model by copying and processing two-dimensional image data through stereo matching algorithms, eliminating the need for physical beam inclining while still obtaining three-dimensional unevenness information

Inventive Principle:

Principle #26Copying

3Measurement precision

If conventional profile analysis is used to determine unevenness, then identification can be made, but the method is not reliable when peaks are not clearly formed at line-space borders

Engineering Contradiction:

Improveunevenness identificationVSAvoiddetermination accuracy

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent transitions from one-dimensional profile analysis to three-dimensional spatial analysis by constructing a three-dimensional model from stereo images, allowing unevenness determination based on spatial coordinates rather than relying on peak formation in two-dimensional profiles

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent creates a virtual three-dimensional model by copying and processing two-dimensional image data through stereo matching algorithms, eliminating the need for physical beam inclining while still obtaining three-dimensional unevenness information

Inventive Principle:

Principle #26Copying

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 precise identification of line and space patterns and unevenness on semiconductor wafers regardless of pattern formation state or image acquisition conditions, improving throughput by eliminating the need for beam inclination.

Implementation Method 1

a charged particle beam device with a function of scanning a charged particle beam one-dimensionally or two-dimensionally

Methodology Applied

Scientific EffectCharged particle beam scanning: Electron Beam

Data Source

PatentUS9329034B2Pattern determination device and computer program

Publication Date: 2016.05.03 HITACHI HIGH TECH CORP

AI summary

An object of the invention is to provide: a sample unevenness device that stably identifies unevenness formed on a sample, regardless of a pattern formation state or image acquisition conditions; and a computer program. As an aspect to achieve the above object, a device and computer program are proposed that obtain the area of a plurality of regions formed by a profile waveform of a given threshold or lower for a profile formed based on a detection signal obtained by scanning with a charged particle beam with respect to the sample; and determine either or both of that a site corresponding to a region with a relatively large area is a concave portion or that a space portion and a site corresponding to a space with a relatively small area is a convex portion or a line portion.