Pulse Plasma Impedance Matching via Phase Synchronization

Solution Overview

Problem

In pulse plasma systems for semiconductor manufacturing, time delays in the feedback loop lead to phase distortion of RF power, causing reflective power and process errors due to rapid changes in plasma state, which complicates impedance matching and reduces process efficiency.

Innovation Solution

A pulse plasma matching system that includes an RF matching box, a network analyzer, a controller, and a phase shifter to measure and synchronize the impedance matching compensation pulse with the RF power pulse, using variable capacitors for capacitance control and reducing reflective power through phase shifting.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If conventional feedback-based impedance matching is used in pulse plasma systems, then the system structure is simple, but time delays cause phase distortion and reflective power

Engineering Contradiction:

Improveimpedance matching system structureVSAvoidimpedance matching accuracy

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The system performs preliminary measurement of plasma impedance using a network analyzer before the RF power pulse is applied. Based on this preliminary measurement, the controller pre-calculates and sets the optimal capacitance values for the matching network, eliminating the need for real-time feedback adjustment during the pulse and avoiding time delay-related phase distortion.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The network analyzer measures plasma impedance in advance, and the controller generates the appropriate capacitance control signal before the RF power pulse is applied to the chamber, ensuring that the impedance matching is already optimized when the plasma process begins.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If real-time feedback control is implemented, then impedance matching accuracy improves, but system complexity and response time increase

Engineering Contradiction:

Improveimpedance matching accuracyVSAvoidfeedback loop delay

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The system performs preliminary measurement of plasma impedance using a network analyzer before the RF power pulse is applied. Based on this preliminary measurement, the controller pre-calculates and sets the optimal capacitance values for the matching network, eliminating the need for real-time feedback adjustment during the pulse and avoiding time delay-related phase distortion.

Inventive Principle:

Principle #10Preliminary action

3Adaptability or versatility

If variable capacitors are used for impedance matching, then matching flexibility improves, but reflective power due to phase distortion increases

Engineering Contradiction:

Improveimpedance matching flexibilityVSAvoidreflective power

Core Design Contradiction:

Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The network analyzer measures plasma impedance in advance, and the controller generates the appropriate capacitance control signal before the RF power pulse is applied to the chamber, ensuring that the impedance matching is already optimized when the plasma process begins.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system uses a network analyzer to measure plasma impedance and feeds this information back to the controller, which adjusts the variable capacitors in the matching network to achieve optimal impedance matching, thereby minimizing reflective power while maintaining flexibility.

Inventive Principle:

Principle #23Feedback

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 system effectively synchronizes the impedance matching compensation pulse with the RF power pulse, reducing reflective power and improving impedance matching in pulse plasma processes, thereby enhancing process stability and reducing errors caused by time delays.

Implementation Method 1

a phase shifter configured to receive the impedance matching compensation pulse and to shift a phase of the impedance matching compensation pulse to synchronize the impedance matching compensation pulse to the RF power pulse

Methodology Applied

Scientific EffectPhase shifting: Phase Modulation

Implementation Method 2

a network analyzer configured to measure an impedance of plasma generated in a process chamber

Methodology Applied

Scientific EffectImpedance measurement: Electrical Impedance Tomography

Implementation Method 3

a controller configured to generate a capacitance control signal corresponding to a plasma impedance value measured by the network analyzer

Methodology Applied

Scientific EffectCapacitance control: Capacitance

Data Source

PatentUS8222821B2Pulse plasma matching systems and methods including impedance matching compensation

Publication Date: 2012.07.17 SAMSUNG ELECTRONICS CO LTD

AI summary

A pulse plasma matching system includes an RF matching box configured to receive an RF power pulse generated by an RF power source, configured to perform a plasma impedance matching, and configured to apply the RF power pulse to a process chamber, and a network analyzer configured to measure an impedance of plasma generated in a process chamber. A controller is configured to generate a capacitance control signal corresponding to a plasma impedance value measured by the network analyzer, configured to supply the capacitance control signal to the RF matching box, and configured to generate an impedance matching compensation pulse, and a phase shifter is configured to receive the impedance matching compensation pulse and to shift a phase of the impedance matching compensation pulse to synchronize the impedance matching compensation pulse to the RF power pulse.