RF Power Feedback Compensation for Resistivity-Driven Etch Rate Drift

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Solution Overview

Problem

Substrate processing systems face variations in deposition or etch rates due to variations in substrate bulk resistivity, leading to defects and increased costs as manufacturers attempt to control substrate properties.

Innovation Solution

A substrate processing system that includes a plasma generator and a sensor to sense RF power parameters, such as RF voltage, current, or phase angle, to compensate for variations in substrate bulk resistivity by adjusting the RF power during plasma processing, using a controller to maintain consistent deposition or etch rates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If substrate bulk resistivity is controlled to maintain consistent deposition or etch rates, then manufacturing precision is improved, but device complexity and cost increase due to additional substrate property control mechanisms

Engineering Contradiction:

Improvedeposition or etch rate consistencyVSAvoidsubstrate property control mechanisms

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The system senses RF power parameters (voltage, current, or impedance) during plasma processing and uses this feedback to detect substrate bulk resistivity variations. The controller then dynamically adjusts RF power in real-time to compensate for these variations, maintaining consistent deposition or etch rates without requiring complex substrate property control mechanisms

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system changes the RF power parameter (voltage, current, or impedance) dynamically during plasma processing based on sensed substrate conditions. By adjusting RF power parameters in response to detected substrate bulk resistivity variations, the system maintains process consistency without controlling substrate properties

Inventive Principle:

Principle #35Parameter changes

2Manufacturing precision

If substrate bulk resistivity variations are monitored and compensated, then manufacturing precision is improved, but use of energy increases due to dynamic RF power adjustment

Engineering Contradiction:

Improvedeposition or etch rate consistencyVSAvoidRF power consumption

Core Design Contradiction:

Manufacturing precisionVSUse of energy by moving object

Solution Approach 1:

The system applies partial compensation by adjusting RF power only to the extent necessary to counteract substrate bulk resistivity variations. Rather than maintaining constant high power throughout the process, the system dynamically modulates power levels, applying energy only when and where needed to maintain process consistency

Inventive Principle:

Principle #16Partial or excessive action

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

The system effectively reduces deposition or etch rate variations by up to 80% by dynamically adjusting RF power based on sensed parameters, improving process uniformity and reducing costs associated with controlling substrate properties.

Implementation Method 1

a plasma generator configured to supply (radio frequency) RF power to an electrode arranged in a processing chamber

Methodology Applied

Scientific EffectRadio frequency power generation:

Implementation Method 2

A sensor is configured to sense a parameter of the RF power supplied to the electrode

Methodology Applied

Scientific EffectRF parameter sensing:

Implementation Method 3

Plasma may be struck to enhance chemical reactions within the processing chamber

Methodology Applied

Scientific EffectPlasma generation: Plasma

Data Source

PatentUS20240363311A1RF power compensation to reduce deposition or etch rate changes in response to substrate bulk resistivity variations

Publication Date: 2024.10.31 LAM RES CORP

AI summary

A substrate processing system includes a plasma generator configured to supply (radio frequency) RF power to an electrode arranged in a processing chamber. A sensor is configured to sense a parameter of the RF power supplied to the electrode. A controller is configured to compensate variations in a rate of a plasma process due to variations in bulk resistivity of a substrate arranged on a substrate support by causing the sensor to sense the parameter at least one of prior to plasma processing of the substrate and after a predetermined period after the plasma processing of the substrate begins; and adjusting the parameter of the RF power for the substrate during the plasma processing of the substrate based on the parameter sensed for the substrate.