Optical End Effector Calibration for Plasma Processing Alignment

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Solution Overview

Problem

Existing end effector calibration methods for plasma processing systems are inefficient due to the need for multiple mechanical fixtures, potential damage to chucks, particle contamination, and inaccuracies caused by pressure differential and manual alignment processes, leading to suboptimal wafer placement and increased rejection rates.

Innovation Solution

An in-situ optical calibration technique that uses image acquisition to determine the centers of the end effector and chuck, calculating the positional difference and providing correction vectors to the robot controller to adjust for misalignment without mechanical fixtures, ensuring accurate calibration under production conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If mechanical fixtures are used for end effector calibration, then alignment can be achieved, but particle contamination and potential damage to chucks occur

Engineering Contradiction:

Improveend effector alignment accuracyVSAvoidparticle contamination

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent replaces mechanical calibration fixtures with an optical measurement system. A camera captures images of the chuck and end effector, and image processing algorithms determine their positions and orientations. This substitution eliminates contact between calibration tools and the chuck, preventing particle contamination and damage while achieving precise alignment through digital analysis of spatial relationships in the captured images

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Ease of operation

If manual alignment process is used, then calibration can be performed, but inaccuracies occur due to pressure differential and manual operation

Engineering Contradiction:

Improvecalibration operation simplicityVSAvoidalignment accuracy

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The patent replaces manual alignment operations with an automated optical measurement and image processing system. The camera captures images, and computer algorithms automatically calculate the positions and orientations of the chuck and end effector, eliminating manual manipulation that causes inaccuracies under pressure differentials while maintaining operational simplicity through automated computation

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system uses image capture and processing to provide feedback on the actual positions and orientations of the chuck and end effector. This feedback enables precise determination of alignment deviations and allows the robot controller to apply corrective transformations, achieving accurate alignment through closed-loop control rather than manual adjustment

Inventive Principle:

Principle #23Feedback

3Adaptability or versatility

If multiple mechanical fixtures are used for different chucks, then various chucks can be calibrated, but device complexity and inventory requirements increase

Engineering Contradiction:

Improvecompatibility with different chucksVSAvoidnumber of calibration fixtures

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent implements a universal optical calibration system that can calibrate any chuck or end effector combination through a single standardized procedure. The camera-based imaging system captures geometric features of different chucks and end effectors, and image processing algorithms adaptively determine their positions and orientations. This universal approach eliminates the need for multiple specialized mechanical fixtures while maintaining compatibility with various chuck and end effector types through flexible computational methods

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

This method eliminates the need for physical fixtures, reduces particle contamination, and ensures accurate wafer placement by replicating production conditions, thereby improving yield and reducing rejection rates.

Implementation Method 1

taking a still image of the chuck and the end effector

Methodology Applied

Scientific EffectLight reflection: Reflection

Data Source

PatentUS8751047B2Systems and methods for calibrating end effector alignment in a plasma processing system

Publication Date: 2014.06.10 LAM RES CORP

AI summary

A method for calibrating alignment of an end effector with respect to a chuck in a plasma processing system is provided. The method including positioning the end effector over the chuck and taking a still image of the chuck and the end effector. The method including processing the still image to ascertain the center of the chuck and the end effector-defined center defined by the end effector. The method including determining a positional difference between the end effector-defined center and the center of the chuck. The method also including providing the positional difference to a robot controller to control a robot mechanism to adjust the positional difference when the end effector transports a wafer.