RF Electrostatic Chuck Filter Circuit for Plasma Processing

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Solution Overview

Problem

In semiconductor processing, the use of radio frequency (RF) power for plasma generation in PECVD leads to capacitive coupling with chucking electrodes, resulting in RF coupling that causes power loss and damage to the power supply.

Innovation Solution

An apparatus with an impedance matching circuit and an electrode filter, including inductors and capacitors, is used to reduce RF coupling by redirecting RF current away from the power supply, preventing damage and power loss.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If RF power is applied to generate plasma in PECVD, then plasma generation is achieved, but capacitive coupling occurs between the plasma and chucking electrode causing RF voltage and current induction

Engineering Contradiction:

Improveplasma generation powerVSAvoidRF coupling effect

Core Design Contradiction:

PowerVSObject-affected harmful factors

Solution Approach 1:

A filter circuit is introduced as an intermediary component between the chucking electrode and the DC power supply. This filter circuit acts as a mediator that blocks RF current while allowing DC current to pass through, thereby protecting the power supply from RF damage without affecting the electrostatic chucking function

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The harmful RF current is extracted and separated from the DC power supply path by introducing the filter circuit. The filter selectively removes RF frequency components from the current flowing through the chucking electrode, allowing only the necessary DC component to reach the power supply

Inventive Principle:

Principle #2Taking out (Extraction)

2Productivity

If RF current flows through the chucking electrode, then plasma generation is maintained, but power loss and damage to the power supply occur

Engineering Contradiction:

Improveplasma generation efficiencyVSAvoidpower supply reliability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The filter circuit serves as a protective intermediary that allows RF current to flow through the chucking electrode for plasma generation while blocking this RF current from reaching the power supply, thus maintaining productivity while protecting reliability

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The filter circuit converts the harmful RF current into a beneficial protective effect by using the RF current itself to demonstrate the filter's blocking capability - the RF current that would normally damage the power supply is instead blocked by the filter, proving the filter's effectiveness while maintaining plasma generation

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 solution effectively minimizes RF current reaching the power supply, reducing damage and power loss, while maintaining sufficient current for plasma generation, thereby improving the reliability of the chucking electrode and substrate processing.

Implementation Method 1

An electrode filter is disposed between the second electrode and the power source. The electrode filter includes a first inductor coupled to the second electrode, a second inductor in series with the first inductor, a third inductor in series with the first inductor and the second inductor, and a resistor in series with the first inductor, the second inductor, and the third inductor.

Methodology Applied

Scientific EffectElectrical Filtering: Filter (electronic)

Implementation Method 2

An impedance matching circuit is disposed between the RF source and the first electrode.

Methodology Applied

Scientific EffectImpedance Matching: Electrical Impedance Tomography

Implementation Method 3

The electrode filter includes a first inductor coupled to the second electrode, a second inductor in series with the first inductor, a third inductor in series with the first inductor and the second inductor

Methodology Applied

Scientific EffectElectrical Inductance: Inductor

Implementation Method 4

A first capacitor is disposed in parallel with the second inductor

Methodology Applied

Scientific EffectCapacitance: Capacitance

Data Source

PatentUS11189517B2RF electrostatic chuck filter circuit

Publication Date: 2021.11.30 APPLIED MATERIALS INC

AI summary

Embodiments described herein relate to apparatus and methods for substantially reducing an occurrence of radio frequency (RF) coupling through a chucking electrode. The chucking electrode is disposed in an electrostatic chuck positioned on a substrate support. The substrate support is coupled to a process chamber body. An RF source is used to generate a plasma in a process volume adjacent to the substrate support. An impedance matching circuit is disposed between the RF source and the chucking electrode is disposed in the electrostatic chuck. An electrostatic chuck filter is coupled between the chucking electrode and the chucking power source.