Replaceable Plasma Chamber Interface With Thermal Choke

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Solution Overview

Problem

The existing upper chamber sections in plasma processing systems are difficult to clean and reseat properly, leading to temperature variability issues that affect plasma processing conditions, and they often require replacement due to thermal mass effects and sensitivity to temperature changes.

Innovation Solution

A replaceable top chamber interface with a monolithic metal cylinder and a ceramic window, featuring a thermal mass for uniformity and a thermal choke to minimize heat transfer, along with a side gas injection system for uniform gas delivery, which includes bifurcated gas lines and symmetrically arranged injectors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the upper chamber section is made with traditional construction, then it provides structural integrity, but it causes temperature variability and difficulty in cleaning and reseat

Engineering Contradiction:

Improvetemperature controlVSAvoidcleaning and reseat

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The upper chamber section is divided into separate components: a top chamber interface (248) and an upper chamber section (244). This segmentation allows the top chamber interface to be removed and cleaned separately, improving ease of operation while maintaining the structural integrity of the overall chamber assembly.

Inventive Principle:

Principle #1Segmentation

2Stability of the object's composition

If the upper chamber section has large thermal mass, then it provides thermal stability, but it causes sensitivity to temperature changes and requires replacement

Engineering Contradiction:

Improvethermal stabilityVSAvoidtemperature control flexibility

Core Design Contradiction:

Stability of the object's compositionVSAdaptability or versatility

Solution Approach 1:

The top chamber interface (248) incorporates a thermal mass specifically at its upper portion to provide localized thermal stability where needed. The lower portion includes a thermal choke with reduced thermal mass to minimize heat transfer to the bottom section. This local differentiation of thermal properties allows the system to maintain thermal stability in critical areas while adapting to temperature control requirements.

Inventive Principle:

Principle #3Local quality

3Temperature

If heat transfer across the chamber interface is not minimized, then thermal equilibrium is easier to achieve, but temperature variability affects plasma processing conditions

Engineering Contradiction:

Improvetemperature uniformityVSAvoidheat transfer

Core Design Contradiction:

TemperatureVSLoss of energy

Solution Approach 1:

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The top chamber interface (248) acts as a thermal intermediary between the upper chamber section and the bottom section. It includes a thermal mass at its upper portion to absorb and distribute heat uniformly, while its lower portion includes a thermal choke to limit heat transfer to the bottom section. This intermediary structure prevents direct heat transfer paths that would cause temperature variability.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 design enhances temperature control and uniformity, reduces heat transfer issues, and facilitates easier maintenance and replacement, ensuring consistent plasma processing conditions and improved thermal management.

Implementation Method 1

a thermal mass at an upper portion of the cylinder, the thermal mass defined by a wider portion of the cylinder between the inner surface and an outer surface extending vertically from the upper flange, the thermal mass being effective to provide azimuthal temperature uniformity of the inner surface

Methodology Applied

Scientific EffectThermal mass: Thermal Energy Storage

Implementation Method 2

a thermal choke at a lower portion of the cylinder effective to minimize transfer of heat across the lower vacuum sealing surface, the thermal choke defined by a thin metal section having a thickness of less than 0.25 inch and extending at least 25% of the length of the inner surface

Methodology Applied

Scientific EffectThermal choke: Thermal Insulation

Implementation Method 3

Induction coil 231 is separated from the plasma by a dielectric window 204 forming the upper wall of the chamber, and generally induces a time-varying electric current in the plasma processing gases to create plasma 220

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 4

a heating and cooling apparatus 246 may operate to control the temperature of the upper chamber section 244 of the plasma processing apparatus 202

Methodology Applied

Scientific EffectHeat transfer: Conduction (thermal)

Data Source

PatentUS10074521B2Replaceable upper chamber parts of plasma processing apparatus

Publication Date: 2018.09.11 LAM RES CORP

AI summary

An upper chamber section of a plasma reaction chamber includes a ceramic window with blind bores in an upper surface for receipt of a thermal couple and a resistance temperature detector, a top chamber interface which comprises an upper surface which vacuum seals against the bottom of the window and a gas injection system comprising 8 side injectors mounted in the sidewall of the top chamber interface and a gas delivery system comprising tubing which provides symmetric gas flow to the 8 injectors from a single gas feed connection.