Multi-scale Spectral Imaging for Semiconductor Metrology

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Solution Overview

Problem

The reduction in semiconductor manufacturing process design rules leads to smaller pattern sizes, resulting in reduced sensitivity and measurement accuracy in existing measurement apparatuses, which struggle to sense non-uniformities and defects due to limited optical resolution and increased complexity in measurement processes.

Innovation Solution

A multi-scale spectral imaging apparatus and method that combines a line-scan spectral imaging system for high-speed measurement of large areas and an angle-resolved spectral imaging system for precise measurement of small regions, using a light source, optical systems, and detectors to achieve high-resolution imaging across various scales.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a point measurement method is used, then measurement precision can be achieved, but measurement speed and productivity are severely reduced requiring hundreds to thousands of hours to measure an entire wafer surface

Engineering Contradiction:

Improvemeasurement precisionVSAvoidmeasurement speed

Core Design Contradiction:

Measurement precisionVSProductivity

Solution Approach 1:

The patent divides the measurement task into two segments: a line-scan spectral imaging system for rapid large-area screening and an angle-resolved spectral imaging system for detailed high-resolution measurement of specific regions of interest. This segmentation allows the system to achieve both high productivity in the screening phase and high measurement precision in the detailed analysis phase, eliminating the need to choose between speed and accuracy.

Inventive Principle:

Principle #1Segmentation

2Manufacturing precision

If the pattern size is reduced due to shrinking design rules, then manufacturing capability is improved, but measurement sensitivity and accuracy are reduced making it difficult to sense non-uniformities

Engineering Contradiction:

Improvepattern sizeVSAvoidmeasurement sensitivity

Core Design Contradiction:

Manufacturing precisionVSMeasurement precision

Solution Approach 1:

The patent introduces angular resolution as an additional dimension for measurement. By measuring not only the intensity but also the angular distribution of reflected light, the angle-resolved spectral imaging system can detect subtle non-uniformities in small patterns that would be invisible to conventional intensity-only measurement methods, thereby maintaining measurement sensitivity even as pattern sizes shrink.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Device complexity

If a single measurement system is used, then device complexity is reduced, but the system cannot simultaneously achieve high-speed large-area measurement and high-resolution small-region measurement

Engineering Contradiction:

Improvesystem configurationVSAvoidmeasurement scale flexibility

Core Design Contradiction:

Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent creates a universal measurement platform that can perform multiple functions: the line-scan spectral imaging system handles rapid large-area inspection, while the angle-resolved spectral imaging system performs detailed high-resolution measurement. Both systems share common infrastructure (light source, stage, control systems), reducing overall device complexity while maintaining the ability to adapt to different measurement scales and requirements.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 fast and precise measurement of large areas and small regions, enhancing measurement sensitivity and accuracy, and addressing the limitations of existing technologies by allowing for high-speed scanning and detailed analysis of semiconductor devices.

Implementation Method 1

a light source configured to generate and output light

Methodology Applied

Scientific EffectLight emission: Light

Implementation Method 2

divide light reflected by the measurement target into divided light

Methodology Applied

Scientific EffectSpectral dispersion: Diffraction

Implementation Method 3

divide the light from the light source into monochromatic light

Methodology Applied

Scientific EffectMonochromatic light separation: Diffraction

Implementation Method 4

slopingly irradiate the monochromatic light onto the measurement target by using a reflective objective lens

Methodology Applied

Scientific EffectLight reflection: Reflection

Implementation Method 5

detect light reflected by the measurement target

Methodology Applied

Scientific EffectLight detection: Photoelectric Effect

Data Source

PatentUS11726046B2Multi-scale spectral imaging apparatuses and methods, and methods of manufacturing semiconductor devices by using the imaging methods

Publication Date: 2023.08.15 SAMSUNG ELECTRONICS CO LTD

AI summary

An imaging apparatus includes a light source configured to generate and output light, a stage having a measurement target thereon, a line-scan spectral imaging (SI) optical system configured to measure the measurement target using a first scale and to slopingly irradiate the light from the light source onto the measurement target in a line beam shape, divide light reflected by the measurement target, and perform imaging of the divided light, and an angle-resolved SI optical system configured to measure the measurement target at a second scale that is smaller than the first scale and configured to divide the light from the light source into monochromatic light, slopingly irradiate the monochromatic light onto the measurement target by using a reflective objective lens, and perform imaging of light reflected by the measurement target.