Automated PSD Sensor Adjustment for Metrology Alignment

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Solution Overview

Problem

Optical metrology systems, such as opto-acoustic systems, require manual alignment and maintenance of PSD sensors, making it time-consuming to adapt to new products or features, and limiting the ability to optimize sensitivity and discover new applications.

Innovation Solution

An automated sensor adjustment mechanism using a movable wave front splitter to dynamically adjust the radiant power distribution between cells of a split-cell detector, allowing for quick modification of sensor settings and optimal data capture.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If manual alignment and maintenance of PSD sensors is used, then the system can operate with simple structure, but it is time-consuming to adapt to new products or features and cannot optimize sensitivity

Engineering Contradiction:
Improveability to adapt to new products or featuresVSAvoidtime-consuming manual alignment and maintenance
Core Design Contradiction:
Adaptability or versatilityVSLoss of time

Solution Approach 1:

The patent implements dynamic adjustment of sensor settings through automated mechanisms. The system can modify sensor parameters, alignment, and sensitivity settings in real-time based on the specific measurement requirements, enabling quick adaptation to different products and features without manual intervention for each change.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system incorporates self-aligning and self-optimizing capabilities that automatically adjust sensor parameters and maintain optimal performance. This self-service functionality eliminates the need for time-consuming manual alignment and maintenance, allowing the system to adapt to new applications autonomously.

Inventive Principle:
Principle #25Self-service

2Measurement precision

If manual modification of sensor settings is required, then the system structure remains simple, but the sensitivity optimization and discovery of new applications is prevented

Engineering Contradiction:
Improvesensitivity of metrology toolVSAvoidcomplexity of automated sensor adjustment mechanism
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent introduces an automated control system that acts as an intermediary between the user and the complex sensor adjustment mechanisms. This intermediary layer manages the complexity of multiple sensor parameters, alignment adjustments, and optimization algorithms, while presenting a simplified interface to the user and achieving high measurement precision through automated sensitivity optimization.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Measurement precision

If multiple PSD sensors are used to measure film thickness, then measurement capability is improved, but manual alignment and maintenance becomes more time-consuming

Engineering Contradiction:
Improvefilm thickness measurement capabilityVSAvoidtime for aligning and maintaining multiple sensors
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent combines multiple PSD sensors into an integrated sensor array system with unified control. This merging approach allows simultaneous operation of multiple sensors for comprehensive film thickness measurement while using centralized automated alignment and maintenance mechanisms, thereby maintaining enhanced measurement capability without the time penalty of individually managing each sensor.

Inventive Principle:
Principle #5Merging (Combining)

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 flexible and automated operation of metrology systems to capture high-quality data, optimize sensor performance, and correlate features of interest, both current and future, in semiconductor manufacturing processes.

Implementation Method 1

The pump beam 10 causes rapid expansion in the surface 16 as shown by bump 15

Methodology Applied
Scientific EffectRapid expansion: Thermal Expansion

Implementation Method 2

This rapid expansion creates a shock or stress wave that is dispersed into the sample 14

Methodology Applied
Scientific EffectShock wave: Shock Wave

Implementation Method 3

As stress waves propagating within the sample 16 intersect the surface 16, they can cause a deformation in the surface 16

Methodology Applied
Scientific EffectStress wave propagation: Ultrasound

Implementation Method 4

the system shown in Fig. 1 can also measure the deflection of a probe beam 12 that is caused by the same stress waves

Methodology Applied
Scientific EffectBeam deflection:

Implementation Method 5

A probe beam 12 is directed onto and reflected from sample 14. The reflected probe beam is incident upon a sensor 20

Methodology Applied
Scientific EffectLight reflection: Reflection

Data Source

PatentEP2668477B1A method and a sensor adjustment mechanism for position sensitive detection
Publication Date: 2020.09.09 ONTO INNOVATION INC
  • EP2668477B1 patent drawingFigure 1~3
  • EP2668477B1 patent drawingFigure 4a~5
  • EP2668477B1 patent drawingFigure 4b

AI summary

An automatically adjustable method for use in opto-acoustic metrology or other types of metrology operations is described. The method includes modifying the operation of a metrology system that uses a PSD style sensor arrangement. The method may be used to quickly adjust the operation of a metrology system to ensure that the data obtained therefrom are of the desired quality. Further, the method is useful in searching for and optimizing data that is or can be correlated to substrate or sample features or characteristics that of interest. Apparatus and computer readable media are also described.