Spectroscopic Ellipsometry Calibration via Selective Parameter Correction

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Solution Overview

Problem

Existing methods for calibrating measuring apparatuses, such as spectroscopic ellipsometry, face challenges in reducing errors between processes and apparatuses, leading to inaccurate measurements and increased defects in product yield due to the need for frequent and time-consuming error correction across multiple apparatuses.

Innovation Solution

A calibration method that determines and corrects only the apparatus parameters with a substantial influence on the measurement spectrum, using a process of generating a measurement spectrum, calculating errors, and calibrating the apparatus based on these errors, thereby reducing the need for subsequent calibration steps and improving measurement reliability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional calibration methods are used for measuring apparatuses, then measurement coverage is comprehensive, but measurement accuracy deteriorates due to errors between processes and apparatuses

Engineering Contradiction:

Improvemeasurement accuracyVSAvoidconsistency between processes and apparatuses

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent changes the calibration approach by determining specific apparatus parameters that have substantial influence on the measurement spectrum, rather than attempting to calibrate all parameters. This selective parameter approach improves measurement accuracy while maintaining reliability across different processes and apparatuses.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent extracts and focuses only on the critical apparatus parameters that substantially influence the measurement spectrum, separating them from other less important parameters. This extraction allows for more accurate and efficient calibration by concentrating resources on the most impactful parameters.

Inventive Principle:

Principle #2Taking out (Extraction)

2Reliability

If comprehensive calibration of all apparatus parameters is performed, then measurement reliability improves, but calibration time and complexity increase

Engineering Contradiction:

Improvemeasurement reliabilityVSAvoidcalibration time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent transforms the calibration process by identifying and focusing only on apparatus parameters with substantial influence on the measurement spectrum. This parameter selection approach maintains measurement reliability while significantly reducing calibration time and complexity compared to comprehensive calibration of all parameters.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent applies partial action by calibrating only the necessary apparatus parameters that substantially influence measurements, rather than performing excessive calibration on all parameters. This partial calibration approach achieves sufficient reliability without the time cost of complete calibration.

Inventive Principle:

Principle #16Partial or excessive action

3Reliability

If frequent error correction is performed across multiple apparatuses, then measurement consistency improves, but productivity decreases due to time-consuming calibration processes

Engineering Contradiction:

Improvemeasurement consistencyVSAvoidproduct yield

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent changes the calibration strategy by determining only the apparatus parameters that have substantial influence on the measurement spectrum. This selective approach maintains measurement consistency across multiple apparatuses while reducing the frequency and duration of calibration processes, thereby improving productivity and product yield.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent applies partial calibration action by focusing only on critical apparatus parameters, enabling faster error correction across multiple apparatuses. This partial approach maintains measurement consistency without the productivity loss associated with comprehensive calibration of all parameters.

Inventive Principle:

Principle #16Partial or excessive action

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

This approach enhances measurement accuracy and reliability by minimizing errors within the measuring apparatuses, reducing defects, and increasing product yield by maintaining consistent apparatus states throughout the measurement process.

Implementation Method 1

When light is reflected from the sample, a polarized state of the reflected light is changed due to physical properties of the material and the thickness of a layer of the sample

Methodology Applied

Scientific EffectReflection: Reflection

Implementation Method 2

Ellipsometry may calculate information about a sample through an analysis of a change in polarized light that is reflected from the sample

Methodology Applied

Scientific EffectPolarisation: Polarisation

Data Source

PatentUS9897486B2Method of calibrating and using a measuring apparatus that performs measurements using a spectrum of light

Publication Date: 2018.02.20 SAMSUNG ELECTRONICS CO LTD

AI summary

A method of calibrating a measuring apparatus includes determining apparatus parameters that have an influence on a measurement spectrum generated by the measuring apparatus, generating the measurement spectrum by exposing a measurement target on a sample to light generated by the measuring apparatus, calculating an error of the apparatus parameters by comparing the measurement spectrum to an ideal spectrum corresponding to the apparatus parameters, and calibrating the measuring apparatus based on the calculated error of the apparatus parameters.