Synchronous Pulse Plasma Etching RF Phase Control

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Solution Overview

Problem

Conventional semiconductor etching processes face challenges in efficiently controlling plasma parameters such as electron temperature, plasma density, and plasma potential, particularly during pulse-modulated RF applications, which can lead to charging and radiation damage.

Innovation Solution

The development of synchronous pulse plasma etching equipment that synchronizes multiple pulse-modulated RF powers with adjustable frequencies, duty ratios, and phase differences, allowing for various operation modes to optimize plasma etching conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional single RF power plasma etching is used, then the process is simple to operate, but the control over plasma parameters (electron temperature, plasma density, plasma potential) is insufficient leading to charging and radiation damage

Engineering Contradiction:

Improvecontrol over plasma parametersVSAvoidRF power system complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The single RF power source is segmented into multiple independent RF power sources (first RF power source and second RF power source), each capable of independent pulse modulation with different frequencies and duty ratios. This segmentation enables separate control of plasma generation and ion acceleration, providing precise control over plasma parameters while reducing charging and radiation damage through optimized pulse timing.

Inventive Principle:

Principle #1Segmentation

2Adaptability or versatility

If multiple RF powers with different frequencies are applied, then plasma parameter control is improved, but the synchronization control complexity increases

Engineering Contradiction:

Improveoperation modesVSAvoidsynchronization control

Core Design Contradiction:

Adaptability or versatilityVSEase of operation

Solution Approach 1:

A phase difference control unit is implemented to monitor and adjust the phase relationship between multiple RF power sources in real-time. This feedback mechanism automatically maintains the desired phase difference between the first and second RF powers, enabling versatile operation modes (such as synchronous mode and asynchronous mode) without requiring complex manual synchronization, thus improving ease of operation while maintaining adaptability.

Inventive Principle:

Principle #23Feedback

3Object-affected harmful factors

If RF electric power is pulse-modulated, then charging damage and radiation damage are suppressed, but the control precision over plasma parameters decreases

Engineering Contradiction:

Improvecharging damage and radiation damageVSAvoidetching precision

Core Design Contradiction:

Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

The system dynamically adjusts the duty ratios and frequencies of multiple RF power sources during the pulse modulation cycle. By independently varying the duty ratio of the first RF power (for plasma generation) and the second RF power (for ion acceleration), the system maintains precise control over plasma parameters even during pulse-off periods, thereby suppressing charging and radiation damage while preserving etching precision through optimized dynamic parameter control.

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 approach enhances the control over plasma etching processes, reducing damage and improving etching efficiency by allowing independent adjustment of RF parameters, thereby improving semiconductor device fabrication.

Implementation Method 1

a first radio frequency power output unit configured to apply a first radio frequency power having a first frequency and a first duty ratio to a first electrode

Methodology Applied

Scientific EffectRadio frequency power:

Implementation Method 2

configured to generate plasma in a plasma etching chamber

Methodology Applied

Scientific EffectPlasma generation: Plasma

Implementation Method 3

electron temperature, plasma density and plasma potential decrease when RF electric power is off

Methodology Applied

Scientific EffectElectron temperature control:

Implementation Method 4

electron temperature, plasma density and plasma potential decrease when RF electric power is off

Methodology Applied

Scientific EffectPlasma density control:

Data Source

PatentUS8460508B2Synchronous pulse plasma etching equipment and method of fabricating a semiconductor device

Publication Date: 2013.06.11 SAMSUNG ELECTRONICS CO LTD

AI summary

Synchronous pulse plasma etching equipment includes a first electrode and one or more second electrodes configured to generate plasma in a plasma etching chamber. A first radio frequency power output unit is configured to apply a first radio frequency power having a first frequency and a first duty ratio to the first electrode, and to output a control signal including information about a phase of the first radio frequency power. At least one second radio frequency power output unit is configured to apply a second radio frequency power having a second frequency and a second duty ratio to a corresponding second electrode among the second electrodes. The second radio frequency power output unit is configured to control the second radio frequency power to be synchronized with the first radio frequency power or to have a phase difference from the first radio frequency power in response to the control signal.