Calibrating Variable Capacitor Positions in Plasma Match Networks

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Solution Overview

Problem

In transformer coupled capacitive tuning systems for plasma processing, manufacturing differences lead to variability in capacitor positions, causing false alarms and incorrect identification of component degradation, resulting in unnecessary replacement of RF match networks and power splitters.

Innovation Solution

A control system with a memory and conversion module that stores and converts actual capacitor positions to comparable 'golden match' positions, using a calibrated conversion model to minimize variability and prevent false alarms, allowing for accurate evaluation of match network performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If capacitor positions are used directly for performance evaluation, then manufacturing variability causes false alarms, but converting positions requires additional processing complexity

Engineering Contradiction:

Improveaccuracy of component degradation identificationVSAvoidcomplexity of position conversion system

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The system performs preliminary calibration by measuring actual capacitor positions across multiple loads and storing reference data before normal operation. This advance preparation creates a conversion model that eliminates the need for real-time complex calculations, resolving the contradiction between reliability and complexity.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent creates a virtual reference model (copy) of ideal capacitor positions based on actual measurements. This copied reference data stored in memory allows direct comparison with current positions without requiring complex real-time conversion calculations, improving reliability while maintaining simplicity.

Inventive Principle:

Principle #26Copying

2Reliability

If capacitor positions are converted to comparable values, then false alarms are reduced, but measurement and conversion processing time increases

Engineering Contradiction:

Improveaccuracy of match network performance evaluationVSAvoidtime for position data processing

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The conversion model is pre-calculated and stored during a calibration phase before normal operation. During actual performance evaluation, the system simply retrieves and compares against pre-computed reference data, eliminating time-consuming real-time conversions and reducing processing time while maintaining high reliability.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system performs the complex conversion and analysis work partially in advance during calibration, rather than completely in real-time. This partial preliminary action significantly reduces the time required during actual operation while still achieving accurate performance evaluation.

Inventive Principle:

Principle #16Partial or excessive action

Data Source

PatentUS10297422B2Systems and methods for calibrating conversion models and performing position conversions of variable capacitors in match networks of plasma processing systems

Publication Date: 2019.05.21 LAM RES CORP

AI summary

A control system is provided and includes a memory and a conversion module. The memory is configured to store position data of first positions of a first variable capacitor of a first match network of a first plasma processing system. Each of the first positions of the first variable capacitor corresponds to a respective one of multiple loads experienced by the first match network. The conversion module is configured to: obtain the position data stored in the memory; determine reference capacitor positions based on the position data; determine a calibrated conversion model based on the reference capacitor positions, where the calibrated conversion model converts second positions of the first variable capacitor to comparable capacitor positions, and where the second positions are positions of the first variable capacitor existing subsequent to the determination of the calibrated conversion model; and store the calibrated conversion model.