Cryopump Gas Estimation via Vacuum Pressure Feedback

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Solution Overview

Problem

Cryopumps used in processes like ion implantation face challenges in determining the optimal regeneration interval due to uncertainty in the amount of by-product gases, leading to potential vacuum failures from either short or excessively long intervals.

Innovation Solution

A cryopumped gas amount estimation device and method that includes a vacuum gauge to measure vacuum pressure and an estimation unit to determine the ultimate pressure and convert it into a gas amount, providing an index for setting the regeneration interval.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the regeneration interval is set short, then vacuum reliability is improved, but productivity deteriorates due to frequent regeneration operations

Engineering Contradiction:

Improvevacuum reliabilityVSAvoidproductivity

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The system uses a vacuum gauge to continuously monitor the vacuum degree and feeds this information back to the control unit. The control unit calculates the cumulative gas amount based on pressure-time integration and compares it against thresholds to automatically determine optimal regeneration timing, replacing fixed-schedule regeneration with demand-driven regeneration based on actual gas accumulation

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent replaces manual or fixed-schedule regeneration decision-making with an automated electronic control system that uses vacuum gauge data, cumulative gas amount calculation, and threshold comparison to intelligently determine regeneration timing, substituting mechanical/time-based scheduling with electronic sensing and computational decision-making

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Productivity

If the regeneration interval is set long, then productivity is improved, but vacuum reliability deteriorates due to potential vacuum failures

Engineering Contradiction:

ImproveproductivityVSAvoidvacuum reliability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system performs preliminary calculation of cumulative gas amount continuously during operation and maintains a running total. By the time regeneration is needed, the system has already accumulated the gas amount data, enabling immediate and accurate regeneration decisions without delay, thus preventing vacuum failures while maximizing productivity

Inventive Principle:

Principle #10Preliminary action

3Device complexity

If manual estimation of gas amount is used, then device complexity is reduced, but measurement precision deteriorates leading to incorrect regeneration timing

Engineering Contradiction:

Improvedevice complexityVSAvoidgas amount measurement precision

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent replaces manual estimation with an automated electronic control system that uses vacuum gauge data and cumulative gas amount calculation (through pressure-time integration) to precisely quantify trapped gas amounts, substituting human judgment with electronic sensing and computational analysis

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system performs self-measurement and self-assessment of gas accumulation using the vacuum gauge and control unit. The control unit automatically calculates cumulative gas amount from vacuum degree data over time, enabling the cryopump system to self-determine when regeneration is needed without external intervention or manual estimation

Inventive Principle:

Principle #25Self-service

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 proper setting of the cryopump regeneration interval, preventing vacuum failures by accurately quantifying the gas amount and maintaining optimal exhaust velocity.

Implementation Method 1

a vacuum gauge which is installed at the cryopump vacuum vessel so as to measure vacuum in the cryopump vacuum vessel and outputs a vacuum measurement signal

Methodology Applied

Scientific EffectVacuum measurement:

Implementation Method 2

A cryopump is a vacuum pump that captures and exhausts gas molecules by condensation or adsorption using a cryopanel cooled to an extremely low temperature

Methodology Applied

Scientific EffectCondensation: Condensation

Implementation Method 3

A cryopump is a vacuum pump that captures and exhausts gas molecules by condensation or adsorption using a cryopanel cooled to an extremely low temperature

Methodology Applied

Scientific EffectAdsorption: Adsorption

Data Source

PatentUS10495082B2Cryopump, cryopumped gas amount estimation device, and cryopumped gas amount estimation method

Publication Date: 2019.12.03 SUMITOMO HEAVY IND LTD

AI summary

A cryopumped gas amount estimation device includes: an ultimate pressure determination unit which determines an ultimate pressure of a cryopump vacuum vessel, based on a vacuum measurement signal representing the degree of vacuum in the cryopump vacuum vessel; and a cryopumped gas amount quantification unit which includes a cryopumped gas amount quantification relation correlating the ultimate pressure with a cryopumped gas amount estimated value and converts the ultimate pressure into the cryopumped gas amount estimated value.