Magnetically Coupled RF Filter for Multi-Zone Heater Leads

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Solution Overview

Problem

The challenge lies in accommodating a large number of heater zones in semiconductor processing chambers, where traditional filter circuits become physically constrained due to the size of inductors needed to filter RF signals from multiple leads, leading to inefficiencies in RF power transmission to the plasma.

Innovation Solution

A resonant circuit comprising a resonant inductor magnetically coupled to multiple inductors on leads from heater zones, allowing for smaller individual inductors and shared inductance, which generates targeted resonant peaks to filter RF signals, thereby reducing the physical volume required in the filter box and enhancing filtering efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional filter circuits are used with multiple inductors for each heater zone lead, then RF signal filtering is achieved, but the physical volume required for the filter box increases significantly

Engineering Contradiction:

ImproveRF signal filteringVSAvoidfilter box volume

Core Design Contradiction:

ReliabilityVSVolume of stationary object

Solution Approach 1:

The patent combines multiple inductors into a single shared inductor that serves all heater zone leads simultaneously. This merging approach eliminates the need for separate inductors for each lead, dramatically reducing the filter box volume while maintaining effective RF signal filtering across all heater zones through the shared inductive component.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The shared inductor is designed to perform the filtering function for multiple heater zone leads simultaneously, making it a universal component that replaces multiple specialized inductors. This multi-functional design achieves the same filtering reliability as traditional circuits but with significantly reduced physical space requirements.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Volume of stationary object

If a resonant circuit with a shared resonant inductor is used, then the filter box volume is reduced, but the complexity of magnetic coupling between inductors is increased

Engineering Contradiction:

Improvefilter box volumeVSAvoidmagnetic coupling configuration

Core Design Contradiction:

Volume of stationary objectVSDevice complexity

Solution Approach 1:

The patent introduces a magnetic core as an intermediary element that facilitates controlled magnetic coupling between the shared inductor and the heater zone leads. This magnetic core mediator simplifies the overall magnetic coupling configuration by providing a centralized path for magnetic flux, making the system easier to design and implement despite the reduced component count.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If multiple separate inductors are used for each heater zone lead, then filtering is effective, but the number of components and space required increases

Engineering Contradiction:

ImproveRF filtering effectivenessVSAvoidnumber of inductors

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges multiple separate inductors into a single shared inductor that handles RF filtering for all heater zone leads. This consolidation maintains filtering effectiveness through the shared inductive reactance while dramatically reducing the component count from multiple inductors to just one, simplifying both the circuit design and physical implementation.

Inventive Principle:

Principle #5Merging (Combining)

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

This solution enables the accommodation of a larger number of heater zones while effectively filtering RF transients, minimizing space usage and ensuring maximum RF power transmission to the plasma, thus improving the processing chamber's operational efficiency.

Implementation Method 1

a resonant inductor that is magnetically coupled to the plurality of inductors

Methodology Applied

Scientific EffectMagnetic coupling: Electromagnetic Induction

Implementation Method 2

The resonant circuit may produce a resonant peak that filters the RF signal

Methodology Applied

Scientific EffectResonance: Resonance

Data Source

PatentUS12198908B2Magnetically coupled RF filter for substrate processing chambers

Publication Date: 2025.01.14 APPLIED MATERIALS INC

AI summary

A semiconductor processing chamber for processing semiconductor substrates may include a pedestal to support a substrate with a heater zones and a wire mesh configured to deliver a Radio Frequency (RF) signal to a plasma. The chamber may also include heater zone controls that deliver current to the heater zones and a filter circuit between the heater zone controls and the heater zones. The filter circuit may include inductors on leads from the heater zones and a resonant circuit with a resonant inductor that is magnetically coupled to the lead inductors. The resonant circuit may produce a resonant peak that filters the RF signal delivered to the wire mesh from the leads from the heater zones to prevent the RF signal from reaching the heater zone controls.