Two-Piece RF Shield Structure for Thermal Gradient Resistance

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Solution Overview

Problem

Conventional semiconductor processing chambers experience thermal gradients that lead to damage of RF shields and warping of pumping plates due to non-uniform heat transfer, causing cracking and warpage during high temperature operations.

Innovation Solution

The use of a two-piece RF shield design with dielectric materials and an air gap between fastener heads and pumping plates to reduce thermal gradients and eliminate bolted connections, minimizing stress and warping.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a single-piece RF shield design is used, then the structure is simpler and easier to manufacture, but thermal gradients cause cracking and structural damage during high temperature operations

Engineering Contradiction:

ImproveRF shield manufacturing simplicityVSAvoidRF shield resistance to thermal gradient damage

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The RF shield is divided into multiple separate pieces rather than being a single monolithic structure. This segmentation allows each piece to independently accommodate thermal expansion and reduces stress concentration, preventing cracking while maintaining manufacturing simplicity of individual components.

Inventive Principle:

Principle #1Segmentation

2Strength

If bolted connections are used to secure pumping plates, then the assembly is more secure, but thermal expansion causes warping and increased spot contact

Engineering Contradiction:

Improvepumping plate assembly securityVSAvoidpumping plate flatness and uniform contact

Core Design Contradiction:

StrengthVSManufacturing precision

Solution Approach 1:

The pumping plate is designed with a flexible or compliant mounting interface that allows it to accommodate thermal expansion without warping. This flexible connection method maintains secure assembly while preserving plate flatness and uniform contact, eliminating the warping problem caused by rigid bolted connections.

Inventive Principle:

Principle #30Flexible shells and thin films

3Use of energy by moving object

If components are tightly coupled to maximize heat transfer, then thermal efficiency is improved, but non-uniform heat transfer creates damaging thermal gradients

Engineering Contradiction:

Improveheat transfer efficiencyVSAvoidthermal gradient damage to chamber components

Core Design Contradiction:

Use of energy by moving objectVSObject-affected harmful factors

Solution Approach 1:

The thermal coupling between components is made non-uniform, with different local regions having different thermal conductances. This local quality variation allows heat transfer to be optimized in critical areas while reducing thermal gradients in other areas, preventing damage from excessive thermal stress.

Inventive Principle:

Principle #3Local quality

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 two-piece RF shield design reduces the likelihood of cracking and warping, enhancing the ability of components to withstand thermal gradients and maintain structural integrity during high temperature processing.

Implementation Method 1

an air gap is provided between the bottom surface of the head and the top surface of the pumping plate... reduces thermal gradients and eliminate bolted connections, minimizing stress and warping

Methodology Applied

Scientific EffectThermal gradient reduction: Thermal Insulation

Implementation Method 2

Each of the lower annular member and the upper annular member may include a dielectric material

Methodology Applied

Scientific EffectDielectric property: Dielectric

Data Source

PatentUS12557254B2Two-piece RF shield design

Publication Date: 2026.02.17 APPLIED MATERIALS INC

AI summary

Exemplary semiconductor processing chambers may include a chamber body. The chambers may include a substrate support assembly disposed within the chamber body. The chambers may include a substrate support assembly having a support plate seated atop a support stem. The chambers may include a radio frequency (RF) shield seated atop the chamber body and extending about a peripheral edge of the support plate. The RF shield may include a lower annular member. The RF shield may include an upper annular member seated atop the lower annular member. The upper annular member may define a lip that protrudes radially outward from an outer surface of the upper annular member. Each of the lower annular member and the upper annular member may include a dielectric material.