RF Generator Pulse Shaping With Sub-Region Feedforward Control

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Solution Overview

Problem

In RF generator systems for plasma processing, achieving precise control of power signals to effectively execute plasma etching is challenging due to the nonlinear and time-varying nature of the load, leading to issues with ion energy distribution and etch rate control.

Innovation Solution

A controller system that incorporates a feedforward control module with tuners, memory for storing prior actuator and output profiles, and a learning module to generate adjustment profiles, allowing for dynamic allocation of samples to sub-regions of the output signal, combining feedback and feedforward control to optimize generator parameters.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If feedforward control is applied to the entire output signal, then pulse shape tracking accuracy is improved, but computational complexity and memory requirements increase significantly

Engineering Contradiction:

Improvepulse shape tracking accuracyVSAvoidcomputational complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The output signal is divided into multiple subregions, with dedicated tuners processing each subregion independently. This segmentation reduces the computational burden on each tuner while maintaining overall pulse shape tracking accuracy across the complete signal waveform

Inventive Principle:

Principle #1Segmentation

2Manufacturing precision

If more tuners are used to process subregions, then control precision is improved, but device complexity increases

Engineering Contradiction:

Improvecontrol precisionVSAvoidnumber of tuners

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The system applies feedforward control selectively to specific subregions where it provides the most benefit, rather than uniformly across the entire signal. This partial application optimizes control precision in critical areas while limiting the number of tuners required

Inventive Principle:

Principle #16Partial or excessive action

3Stability of the object's composition

If feedback control is used alone, then system stability is maintained, but response speed and accuracy to dynamic changes decrease

Engineering Contradiction:

Improvesystem stabilityVSAvoidresponse speed

Core Design Contradiction:

Stability of the object's compositionVSSpeed

Solution Approach 1:

The feedforward control component predicts required adjustments based on the desired output waveform before errors occur, enabling proactive compensation for dynamic changes. This preliminary action works in conjunction with feedback control to maintain stability while significantly improving response speed to transient conditions

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS20250006478A1Pulse-Shaping Using A Sub-Region Tuning Apparatus And Method

Publication Date: 2025.01.02 JPMORGAN CHASE BANK N A AS COLLATERAL AGENT

AI summary

A controller for a generator includes a feedforward control module. The feedforward control module is configured to generate an adjustment profile to control a parameter of a generator in accordance with a desired output signal. The feedforward control module generates a plurality of adjustment values in accordance with sub-regions of the output signal. Each sub-region includes a portion of the desired output signal.