DC-Biased Cross-Feed Manifold for Ion-Reduced Plasma Mixing

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Solution Overview

Problem

Conventional single feed manifolds are inefficient for gas injection and mixing in substrate processing, leading to damage of ICP units due to NF3 gas passing through the ignition chamber, high etch rates, and substrate quality issues from positive ions in plasma.

Innovation Solution

A DC biased cross feed manifold structure with a vertically disposed manifold cylinder, top and bottom injection units, and a filter, using conductive materials for the cylinder and ceramic for the injection units, along with a DC bias power source to reduce positive ions and enhance gas mixing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If NF3 gas is fed through the RPU at the top, then gas injection is achieved, but the ICP unit is damaged by F radicals and high etch rates occur

Engineering Contradiction:

Improvegas injectionVSAvoiddamage to ICP unit and high etch rates

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent inverts the conventional gas injection approach by introducing reactant gases at the bottom of the manifold rather than the top. This reversal prevents NF3 from passing through the ignition chamber, eliminating F radical damage to the ICP unit while maintaining effective gas injection for substrate processing

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The manifold is segmented into multiple injection points distributed along its length, with reactant gas inlets positioned at the bottom and source gas inlets positioned at the top. This segmentation allows independent control of gas flows and prevents harmful interactions between NF3 and the ignition chamber

Inventive Principle:

Principle #1Segmentation

2Device complexity

If single feed manifold is used, then device complexity is reduced, but gas injection and mixing efficiency deteriorates

Engineering Contradiction:

Improvemanifold structureVSAvoidgas injection and mixing efficiency

Core Design Contradiction:

Device complexityVSProductivity

Solution Approach 1:

The manifold is divided into multiple injection units with separate reactant gas and source gas inlets distributed along its length. This segmentation enables simultaneous injection of multiple gas types with independent flow control, significantly improving mixing efficiency while maintaining reasonable structural complexity

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent combines multiple gas injection functions into a single manifold structure, integrating both reactant gas and source gas delivery systems. This merging approach maintains device simplicity while achieving efficient gas mixing through multiple injection points and controlled flow paths

Inventive Principle:

Principle #5Merging (Combining)

3Power

If positive ions are present in plasma, then plasma generation is maintained, but substrate quality deteriorates due to ion damage

Engineering Contradiction:

Improveplasma generationVSAvoidsubstrate quality

Core Design Contradiction:

PowerVSManufacturing precision

Solution Approach 1:

The DC biased manifold acts as an intermediary element between the plasma source and substrate. By applying a DC bias, it selectively filters positive ions from the plasma flow while allowing neutral radicals to pass through, thus protecting the substrate from ion damage while maintaining plasma generation

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the electrical parameter of the manifold by applying a DC bias voltage. This parameter change enables the manifold to function as an ion filter, selectively removing positive ions from the plasma flow based on their charge, thereby improving substrate quality without affecting overall plasma generation

Inventive Principle:

Principle #35Parameter changes

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 reduces positive ions in the plasma flow, optimizing substrate processing by minimizing ion damage and enhancing gas mixing efficiency.

Implementation Method 1

a direct current (DC) bias power source configured to supply negatively biased DC to the manifold cylinder

Methodology Applied

Scientific EffectElectrostatic attraction: Electrostatics

Implementation Method 2

the manifold cylinder is made of a highly electrically conductive material comprising at least one of Copper (Cu), Aluminum (Al), Zinc (Zn), Nickel (Ni), Iron (Fe), and Lead (Pb) or a mixture thereof

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentUS20260055505A1DC bias dual cross feed manifold and a reactor using the same

Publication Date: 2026.02.26 ASM IP HLDG BV

AI summary

A manifold structure used in reactors which process substrates and the reactor equipped with the manifold structure are disclosed. The manifold structure comprises a manifold cylinder disposed vertically and comprising an electrical inlet; a direct current (DC) bias power source configured to supply negatively biased DC to the manifold cylinder and further configured to be connected to the electrical inlet; a top injection unit disposed at topside of the manifold cylinder and comprises a reactant gas inlet tube and configured to receive a reactant gas via the reactant gas inlet tube; and a bottom injection unit disposed at downside of the manifold cylinder and comprises a source gas inlet tube and configured to receive a source gas via the source gas inlet tube, wherein the manifold cylinder is made of a highly electrically conductive material.