Mode-Switching Plasma System for Semiconductor Fabrication

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Solution Overview

Problem

Conventional plasma sources lack the ability to transition smoothly between purely inductive and purely capacitive coupling modes during operation, limiting their application in semiconductor fabrication where precise control over plasma properties is essential for nanoscale feature formation.

Innovation Solution

A mode-switching plasma system that reconfigures electrical connections to a plasma coil, allowing for fast and smooth transitions between inductive and capacitive coupling modes by switching between different tap configurations using programmable controllers and retractable electrodes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If conventional plasma sources operate in a fixed coupling mode (inductive or capacitive), then the plasma properties are stable for that mode, but the system cannot transition between modes to achieve diverse plasma properties for different processing steps

Engineering Contradiction:

Improveability to transition between inductive and capacitive coupling modesVSAvoidcomplexity of reconfigurable electrical connection system

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The system employs dynamically reconfigurable electrical connections through retractable electrodes that can be extended or retracted to contact different taps on the coil structure. This dynamic reconfiguration enables transition between inductive and capacitive coupling modes without requiring multiple fixed plasma sources, thus improving adaptability while controlling complexity.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The coil structure is segmented with multiple taps at different positions, allowing selective electrical connection to different portions of the coil. This segmentation enables the system to switch between coupling modes by connecting to specific taps, providing mode versatility without requiring a completely different coil structure for each mode.

Inventive Principle:

Principle #1Segmentation

2Adaptability or versatility

If the plasma processing system uses a single fixed coil configuration, then the equipment structure is simple, but it cannot provide tailored plasma properties (ion-rich or radical-rich) for different processing steps

Engineering Contradiction:

Improvecapability to provide ion-rich and radical-rich plasmasVSAvoidprecision control of plasma properties for nanoscale feature formation

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

Different taps on the coil structure are positioned at specific locations to create local variations in electrical connection points. By selecting which taps to connect, the system can locally modify the plasma properties (ion-rich or radical-rich) without changing the overall coil structure, enabling precise control for different processing steps while maintaining structural simplicity.

Inventive Principle:

Principle #3Local quality

3Adaptability or versatility

If multiple separate plasma sources are used for different processing steps, then each source can be optimized for its specific function, but the equipment complexity and cost increase significantly

Engineering Contradiction:

Improvemulti-step plasma process capabilityVSAvoidnumber of plasma sources and equipment components

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The single plasma processing system is designed with multi-functionality by incorporating reconfigurable electrical connections that allow it to perform multiple plasma processing steps using different coupling modes. This universal design eliminates the need for multiple separate plasma sources, reducing equipment complexity while maintaining the capability to perform diverse plasma processes with tailored properties.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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

Enables precise control over plasma properties, facilitating the formation of nanoscale features by switching between ion-rich and radical-rich plasmas, enhancing the capability to perform multi-step plasma processes with tailored plasma properties for semiconductor manufacturing.

Implementation Method 1

A mode-switching plasma system that reconfigures electrical connections to a plasma coil, allowing for fast and smooth transitions between inductive and capacitive coupling modes

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentUS11251021B2Mode-switching plasma systems and methods of operating thereof

Publication Date: 2022.02.15 TOKYO ELECTRON LTD

AI summary

A plasma processing apparatus includes a plasma processing chamber, a coil having an uncoiled length L disposed adjacent to the plasma processing chamber, and a plurality of retractable conductors each configured to make electrical contact with the coil in an extended position. A first tap position is located substantially at a distance L/2 measured from a first end along the coil, a second tap position neighboring the first tap position and located substantially at the distance L/2 measured from the first end along the coil, and a third tap position located substantially at the first end of the coil. A controller is configured to operate the plasma processing apparatus in a first operating mode to sustain an inductively coupled plasma and in a second operating mode to sustain a capacitively coupled plasma using subsets of the retractable conductors in the extended position.