Dual Hollow Cathode Ion Source for PECVD Contamination

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Solution Overview

Problem

Existing ion sources are complex and prone to contamination, requiring additional components like electrodes, magnetic fields, and neutralizers, and often fail to effectively manage electrical imbalances and dielectric deposition during plasma-enhanced chemical vapor deposition processes.

Innovation Solution

A hollow-cathode-based ion source design that eliminates the need for additional electrodes, accelerating grids, magnetic fields, or neutralizers by using two hollow cathodes that alternate as electrodes to generate and accelerate ions, protecting cathode and anode surfaces from contamination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If additional components (electrodes, magnetic fields, neutralizers) are added to extract and accelerate ions, then ion beam generation capability is improved, but device complexity increases

Engineering Contradiction:

Improveion beam generation capabilityVSAvoiddevice complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent combines the plasma generation function and ion acceleration function into a single hollow cathode structure. The hollow cathode generates plasma through gas discharge and simultaneously accelerates ions through the pressure gradient created by gas flow from the cathode cavity through the orifice, eliminating the need for separate electrodes and magnetic fields.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The hollow cathode serves multiple functions: it generates plasma through gas discharge, accelerates ions through pressure gradients, and provides charge balance through electron emission. This multi-functional design replaces multiple specialized components in conventional ion sources.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Productivity

If additional components (electrodes, magnetic fields, neutralizers) are added to extract and accelerate ions, then ion beam generation capability is improved, but manufacturing complexity increases

Engineering Contradiction:

Improveion beam generation capabilityVSAvoidease of manufacture

Core Design Contradiction:

ProductivityVSEase of manufacture

Solution Approach 1:

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent extracts and eliminates unnecessary components from conventional ion source designs, retaining only the essential hollow cathode structure that can perform both plasma generation and ion acceleration functions, thereby simplifying manufacturing.

Inventive Principle:

Principle #2Taking out (Extraction)

3Productivity

If conventional ion sources are used in PECVD processes, then substrate treatment capability is improved, but surface contamination increases

Engineering Contradiction:

Improvesubstrate treatment capabilityVSAvoidsurface contamination

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent converts the gas flow that could carry contaminants into a beneficial mechanism by using it to create a pressure gradient for ion acceleration. The directed gas flow from the hollow cathode cavity through the orifice accelerates ions toward the substrate while the cathode structure itself protects against contamination.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The hollow cathode structure provides preliminary protection against contamination by confining the plasma generation and ion acceleration processes within the cathode cavity, preventing precursor gases and reaction products from directly contacting and contaminating the cathode and anode surfaces before ion beam formation.

Inventive Principle:

Principle #9Preliminary anti-action

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 simplifies the ion source, reduces complexity, and effectively generates and accelerates ions without additional components, while protecting surfaces from contamination, enabling efficient ion beam production for various applications.

Implementation Method 1

When voltage is applied across the two hollow cathodes, gas discharge occurs within the cathode cavities

Methodology Applied

Scientific EffectGas discharge: Electric Arc

Implementation Method 2

Each of the first and second ion acceleration cavities is sufficient to enable extraction and acceleration of ions without the use of additional electrodes, accelerating grids, magnetic fields, or other additional components

Methodology Applied

Scientific EffectPressure gradient: Pressure Gradient

Data Source

PatentUS10242846B2Hollow cathode ion source

Publication Date: 2019.03.26 AGC INC

AI summary

An ion source includes a chamber. The ion source further includes a first hollow cathode having a first hollow cathode cavity and a first plasma exit orifice and a second hollow cathode having a second hollow cathode cavity and a second plasma exit orifice. The first and second hollow cathodes are disposed adjacently in the chamber. The ion source further includes a first ion accelerator between and in communication with the first plasma exit orifice and the chamber. The first ion accelerator forms a first ion acceleration cavity. The ion source further includes a second ion accelerator between and in communication with the second plasma orifice and the chamber. The second ion accelerator forms a second ion acceleration cavity. The first hollow cathode and the second hollow cathode are configured to alternatively function as electrode and counter-electrode to generate a plasma. Each of the first ion acceleration cavity and the second ion acceleration cavity are sufficient to enable the extraction and acceleration of ions.