Pulse-Modulated Microwave Monitoring Correction Function

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Solution Overview

Problem

Existing methods for monitoring pulse-modulated microwaves with bandwidth struggle to accurately detect the ON level of power, leading to instability and misfire in plasma processing, as they rely on a fixed 50% threshold that does not account for power variations, resulting in reduced accuracy and potential errors in duty ratio and pulse width measurement.

Innovation Solution

A method and device that use a determination threshold value set between 0% and 50% of the setting power, specifically up to 0.4%, to accurately detect the ON level of pulse-modulated microwaves with bandwidth, and a correction function based on linear approximation of pulse width errors to improve monitoring accuracy across varying setting powers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a fixed 50% threshold is used to detect the ON level of pulse-modulated microwaves, then the detection method is simple, but the measurement precision deteriorates due to power variations

Engineering Contradiction:

Improvedetection method simplicityVSAvoidON level detection accuracy

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The patent applies dynamics by making the determination threshold adaptive rather than fixed. The threshold is dynamically adjusted based on the relationship between setting power and measured power, allowing the detection method to adapt to different power levels and maintain high measurement precision across varying conditions while preserving operational simplicity through automated threshold calculation.

Inventive Principle:

Principle #15Dynamics

2Measurement precision

If a determination threshold less than 50% of setting power is used, then the measurement precision of ON level detection is improved, but the device complexity increases due to additional correction functions

Engineering Contradiction:

ImproveON level detection accuracyVSAvoidcorrection function complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies parameter changes by systematically varying the determination threshold based on the setting power parameter. Instead of using a fixed threshold, the system adjusts the threshold parameter according to the relationship between setting power and measured power, enabling accurate detection across different power levels. The correction function uses linear approximation to manage complexity while maintaining precision.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces complex mechanical or hardware-based threshold adjustment mechanisms with a computational correction function. By using software-based linear approximation to calculate and apply threshold corrections, the system achieves high measurement precision without requiring complex physical adjustment mechanisms, thereby managing device complexity through intellectual rather than mechanical means.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Productivity

If pulse width error is not corrected, then the measurement process is faster, but the manufacturing precision of duty ratio and pulse width deteriorates

Engineering Contradiction:

Improvemeasurement speedVSAvoidduty ratio and pulse width accuracy

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent applies preliminary action by pre-calculating correction values for pulse width errors based on linear approximation. The correction function is prepared in advance through calibration measurements, allowing the system to quickly apply corrections during actual measurements without performing complex real-time calculations. This maintains high measurement speed while ensuring accurate duty ratio and pulse width measurements through pre-computed correction factors.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS11249126B2Method of determining correction function

Publication Date: 2022.02.15 TOKYO ELECTRON LTD

AI summary

A method includes measuring first travelling wave power of a microwave having a single frequency peak and second travelling wave power having a single frequency peak, acquiring duty ratios of the first travelling wave power and the second travelling wave power based on measured values and a first determination threshold value, measuring third travelling wave power of a microwave having a bandwidth and fourth travelling wave power having a bandwidth, acquiring duty ratios of the third travelling wave power and the fourth travelling wave power based on measured values and a second determination threshold value, approximating a pulse width error between the first travelling wave power and the third travelling wave power and a pulse width error between the second travelling wave power and the fourth travelling wave power with linear functions, and determining the correction function based on the linear functions.