AOI and POI Error Compensation in Ellipsometer Systems

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Solution Overview

Problem

Current methods for setting and maintaining precise Angle-Of-Incidence (AOI) and Plane-Of-Incidence (POI) in ellipsometer systems are costly and labor-intensive, leading to errors in sample characterization data due to deviations between intended and actual settings.

Innovation Solution

A method utilizing multi-element alignment detectors to monitor and correct errors in AOI and POI by analyzing signals from these detectors, allowing for physical adjustment and data compensation without the need for expensive equipment to precisely set intended AOI and POI values.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If expensive equipment is used to precisely set AOI and POI, then measurement precision is improved, but device complexity and cost increase

Engineering Contradiction:
ImproveAOI and POI setting precisionVSAvoidequipment complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical alignment systems with a computational approach. Multi-element detectors capture spatial distribution of reflected light, and software algorithms calculate actual AOI and POI values from these measurements, eliminating the need for expensive mechanical precision positioning systems.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces multi-element detectors as intermediary devices between the sample and the measurement system. These detectors measure the spatial distribution of reflected light and provide data that serves as an intermediary step to calculate actual AOI and POI, avoiding direct reliance on complex mechanical positioning.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Device complexity

If manual alignment methods are used, then device complexity is reduced, but measurement precision deteriorates due to errors between intended and actual settings

Engineering Contradiction:
Improvealignment system complexityVSAvoidAOI and POI accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent implements a feedback mechanism where multi-element detectors continuously monitor the spatial distribution of reflected light, and the system calculates actual AOI and POI values from these measurements. This feedback loop allows real-time detection and correction of alignment deviations without increasing mechanical complexity.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent replaces manual mechanical alignment with an automated optical measurement and calculation system. The multi-element detectors and software algorithms together form a system that automatically determines actual AOI and POI values, eliminating manual alignment errors while keeping the hardware relatively simple.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Manufacturing precision

If expensive precision alignment equipment is used, then manufacturing precision is improved, but ease of manufacture worsens

Engineering Contradiction:
Improvealignment precisionVSAvoidsystem implementation difficulty
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent replaces expensive precision mechanical alignment equipment with a combination of commercially available multi-element detectors and software algorithms. This substitution maintains high alignment precision while significantly improving ease of manufacture, as the required components are off-the-shelf items that can be integrated into existing systems.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent uses multi-element detectors to create a digital copy or representation of the light spatial distribution. This optical information is then processed by software to calculate AOI and POI values, replacing the need for physical precision mechanical systems with information-based measurements that are easier to manufacture and implement.

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 accurate and cost-effective detection and correction of AOI and POI errors during sample characterization, improving data analysis without requiring expensive systems for precise physical alignment.

Implementation Method 1

directing electromagnetic beams at samples at known angles (AOI) and planes (POI) of incidence

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP2698598B1System and method for setting and compensating errors in AOI and POI of a beam of EM radiation
Publication Date: 2015.12.02 J A WOOLLAM CO
  • EP2698598B1 patent drawingFigure 1a~4
  • EP2698598B1 patent drawingFigure 5~6
  • EP2698598B1 patent drawingFigure 7~8

AI summary

System and methodology for setting, an compensating detected errors between intended an realized Angle-of-Incidence (AOI) an Plane-of-Incidence (POI) settings in ellipsometer an the like systems during analysis of sample characterizing data.