RF Generator Controlled Overshoot for Plasma Ignition

Solution Overview

Problem

Balanced RF amplifiers used in plasma processing chambers face issues with uneven power dissipation during load mismatch, which can damage the amplifier, especially during plasma ignition where high power is required into a non-matched load.

Innovation Solution

A RF generator with a half-bridge circuit and control circuit that connects and disconnects auxiliary and primary DC power supplies in series to produce a controlled overshoot in power output, allowing for a higher-than-normal power level during plasma ignition and returning to nominal levels, thereby managing power distribution effectively.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If balanced amplifier power profile is reduced to prevent damage during load mismatch, then amplifier reliability is improved, but plasma ignition capability deteriorates

Engineering Contradiction:

Improveamplifier reliabilityVSAvoidplasma ignition power

Core Design Contradiction:

ReliabilityVSPower

Solution Approach 1:

The control circuit detects load mismatch conditions (such as during plasma ignition) and proactively adjusts the power profile of one amplifier before damage can occur. By提前 reducing the power of the amplifier that would otherwise dissipate excessive power, the system prevents damage while still allowing the other amplifier to deliver the substantial power needed for plasma ignition.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system applies different power profiles to the two amplifiers based on their individual power dissipation characteristics during load mismatch. Instead of uniformly reducing power from both amplifiers, only the amplifier at risk of dissipating excessive power has its power reduced, while the other amplifier maintains or increases its power output to compensate.

Inventive Principle:

Principle #3Local quality

2Power

If substantial power is delivered into non-matched load during plasma ignition, then plasma ignition capability is improved, but amplifier damage risk increases

Engineering Contradiction:

Improveplasma ignition powerVSAvoidamplifier safety

Core Design Contradiction:

PowerVSReliability

Solution Approach 1:

The system applies different power profiles to the two amplifiers based on their individual power dissipation characteristics during load mismatch. Instead of uniformly reducing power from both amplifiers, only the amplifier at risk of dissipating excessive power has its power reduced, while the other amplifier maintains or increases its power output to compensate.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The control circuit continuously monitors the operating conditions of the amplifiers and dynamically adjusts their power profiles based on real-time feedback. During load mismatch conditions, the control circuit detects which amplifier is dissipating more power and adjusts that amplifier's power profile accordingly, allowing the system to deliver substantial power into non-matched loads while preventing amplifier damage.

Inventive Principle:

Principle #23Feedback

3Ease of operation

If balanced amplifier power profile is reduced to manage power distribution, then power distribution control is improved, but plasma processing productivity deteriorates

Engineering Contradiction:

Improvepower distribution controlVSAvoidplasma processing efficiency

Core Design Contradiction:

Ease of operationVSProductivity

Solution Approach 1:

The control circuit detects load mismatch conditions (such as during plasma ignition) and proactively adjusts the power profile of one amplifier before damage can occur. By提前 reducing the power of the amplifier that would otherwise dissipate excessive power, the system prevents damage while still allowing the other amplifier to deliver the substantial power needed for plasma ignition.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system applies different power profiles to the two amplifiers based on their individual power dissipation characteristics during load mismatch. Instead of uniformly reducing power from both amplifiers, only the amplifier at risk of dissipating excessive power has its power reduced, while the other amplifier maintains or increases its power output to compensate.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS10074518B2Apparatus for controlled overshoot in a RF generator

Publication Date: 2018.09.11 AES GLOBAL HLDG PTE LTD

AI summary

A radio-frequency (RF) generator is provided that produces a controlled overshoot. One embodiment includes a RF power amplifier and a direct-current (DC) power supply that includes a primary DC power supply, an auxiliary DC power supply, a half-bridge circuit, and a control circuit. The half-bridge circuit, in a first switching state, electrically connects, in series, the auxiliary DC power supply with the primary DC power supply and, in a second switching state, electrically disconnects the auxiliary DC power supply from the primary DC power supply. The control circuit places the half-bridge circuit in the first switching state for a first period of time and places the half-bridge circuit in the second switching state for a second period of time to produce a controlled overshoot in the power produced by the RF generator throughout the first period of time.