TES Edge Ring RF Voltage Feedback for Etch Uniformity

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Solution Overview

Problem

Existing substrate processing systems face challenges in achieving precise control over RF voltages at the edge ring, leading to non-uniform etch rates and distorted profiles due to capacitive coupling and impedance changes, which affect etch uniformity and profile consistency.

Innovation Solution

A voltage control system with a tunable edge sheath (TES) ring and embedded TES power electrode and probe, capable of directly or indirectly detecting RF voltages and phases, allowing for precise adjustment of RF signals to match target values and compensate for instability or degradation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional RF voltage control is used at the edge ring, then the system structure remains simple, but etch uniformity and profile consistency deteriorate due to capacitive coupling and impedance changes

Engineering Contradiction:

Improveetch uniformityVSAvoidvoltage control system complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent implements a feedback control system where RF voltage sensors measure the actual RF voltages at the edge ring, and the controller adjusts the RF power delivery based on these measurements to maintain precise voltage control despite capacitive coupling and impedance changes

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent replaces conventional direct electrical connection methods with RF voltage sensors that capacitively couple to the edge ring, allowing non-contact voltage measurement and control that eliminates the harmful effects of direct electrical connections

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Manufacturing precision

If RF voltage control is not implemented, then the device complexity remains low, but etch rate uniformity and processing consistency deteriorate

Engineering Contradiction:

Improveprocessing consistencyVSAvoidcontrol system structure

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The controller continuously monitors RF voltages at the edge ring through sensors and dynamically adjusts the RF power delivery to maintain consistent processing conditions, ensuring uniform etch rates and processing consistency

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent introduces RF voltage sensors as intermediary devices that capacitively couple to the edge ring to measure voltages without directly interfering with the plasma process, enabling precise control while minimizing system complexity

Inventive Principle:

Principle #24Intermediary (Mediator)

3Manufacturing precision

If precise RF voltage adjustment is implemented, then etch uniformity improves, but the difficulty of detecting and measuring RF voltages increases

Engineering Contradiction:

Improveprofile consistencyVSAvoidRF voltage measurement difficulty

Core Design Contradiction:

Manufacturing precisionVSDifficulty of detecting and measuring

Solution Approach 1:

The patent uses RF voltage sensors that capacitively couple to the edge ring as intermediary measurement devices, allowing non-contact detection of RF voltages and phases without direct electrical connection, thereby simplifying the measurement process while maintaining precision

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces complex direct electrical measurement methods with capacitive coupling-based RF voltage sensors that can measure high-frequency RF signals without physical contact, reducing measurement difficulty and improving profile consistency

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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

Enhances etch rate uniformity and reduces processing variability by accurately controlling RF voltages and phases at the edge ring, minimizing distortion and improving substrate processing consistency.

Implementation Method 1

a TES power electrode capacitively coupled to the edge ring and configured to receive a first radio frequency (RF) voltage signal

Methodology Applied

Scientific EffectCapacitive coupling: Capacitance

Implementation Method 2

The TES probe is capacitively coupled to the edge ring for indirect detection of the second RF voltage signal

Methodology Applied

Scientific EffectCapacitive coupling: Capacitance

Implementation Method 3

The TES probe directly contacts the edge ring for direct detection of the second RF voltage signal

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentUS20260018391A1Edge ring voltage and phase measurement and control for substrate processing systems

Publication Date: 2026.01.15 LAM RES CORP

AI summary

A voltage control system is disclosed and includes: an edge ring configured to be disposed on a substrate support and surround an outer periphery of a substrate; a tunable edge sheath (TES) ring; a generator; and a controller. The TES ring includes: a TES power electrode capacitively coupled to the edge ring and configured to receive a first radio frequency (RF) voltage signal; and a TES probe electrically coupled to the edge ring and configured to detect a second RF voltage signal at the edge ring. The controller is configured to, based on the second RF voltage signal, control the generator to adjust the first RF voltage signal.