Showerhead Support Structure for Uniform Gas Flow

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Solution Overview

Problem

In plasma enhanced chemical vapor deposition (PECVD) processes, the typical center support schemes for gas distribution showerheads interfere with gas flow, leading to non-uniform deposition on large area substrates due to sagging or bowing caused by temperature and pressure variations.

Innovation Solution

The use of center support members and suspension fittings that obstruct some gas passages while providing alternative flow paths through the gas distribution showerhead, maintaining the processing space and preventing sagging or bowing, thus ensuring uniform gas distribution and deposition.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If center support members are added to maintain the horizontal profile of the showerhead, then structural stability is improved, but gas flow uniformity deteriorates due to obstruction of gas passages

Engineering Contradiction:

Improvehorizontal profile stabilityVSAvoiddeposition uniformity

Core Design Contradiction:

Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

The gas distribution system is segmented into multiple independent gas passages within the showerhead. When support members obstruct certain passages, alternative passages remain open to maintain gas flow. This segmentation ensures that the support structure can provide structural stability without completely blocking gas distribution, thereby maintaining both profile stability and deposition uniformity

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the showerhead are designed with different properties. The areas where support members are located have obstructed gas passages, while other regions maintain open passages for gas flow. This local differentiation allows the support structure to stabilize the horizontal profile in specific areas without compromising overall gas distribution uniformity

Inventive Principle:

Principle #3Local quality

2Strength

If the showerhead is supported at the center to prevent sagging, then structural integrity is improved, but gas flow distribution deteriorates due to interference with gas passages

Engineering Contradiction:

Improvestructural integrityVSAvoidgas flow efficiency

Core Design Contradiction:

StrengthVSProductivity

Solution Approach 1:

Alternative gas passages act as intermediaries to bypass the support members. When support members obstruct direct gas passages, the alternative passages provide a mediator path for gas flow, allowing the support structure to maintain structural integrity while gas flow efficiency is preserved through the alternative routes

Inventive Principle:

Principle #24Intermediary (Mediator)

3Stability of the object's composition

If the showerhead structure is rigid to maintain shape at high temperatures, then thermal stability is improved, but adaptability to thermal expansion deteriorates

Engineering Contradiction:

Improvethermal stabilityVSAvoidthermal expansion accommodation

Core Design Contradiction:

Stability of the object's compositionVSAdaptability or versatility

Solution Approach 1:

The showerhead design incorporates dynamic characteristics that allow it to adapt to thermal conditions. While the overall structure maintains rigidity for thermal stability, the gas passage system and support configuration allow for controlled adjustments that accommodate thermal expansion, enabling the structure to maintain both stability and adaptability under varying temperature conditions

Inventive Principle:

Principle #15Dynamics

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 maintains the horizontal profile of the gas distribution showerhead, ensuring uniform film thickness across the substrate by preventing interference with gas flow and accommodating thermal expansion, thereby improving deposition uniformity.

Implementation Method 1

Showerheads are commonly made of aluminum and are subject to expansion and contraction while enduring the temperatures during the PECVD processes

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

a first bore formed in the first side that is fluidly coupled to a second bore formed in the second side by a restricting orifice

Methodology Applied

Scientific EffectPressure drop: Pressure Drop

Implementation Method 3

The showerhead is electrically biased to ignite the processing gas into a plasma

Methodology Applied

Scientific EffectPlasma: Plasma

Data Source

PatentUS10087524B2Showerhead support structure for improved gas flow

Publication Date: 2018.10.02 APPLIED MATERIALS INC

AI summary

Embodiments of the present invention generally provide apparatus and methods for supporting a gas distribution showerhead in a processing chamber. In one embodiment, a gas distribution showerhead for a vacuum chamber is provided. The gas distribution showerhead comprises a body having a first side and a second side opposite the first side, and a plurality of gas passages formed through the body, the gas passages comprising a first bore formed in the first side that is fluidly coupled to a second bore formed in the second side by a restricting orifice, and a suspension feature formed in the first bore of at least one of the gas passages.