Vacuum Cooling Control for Condensation-Free Ion Milling

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Solution Overview

Problem

Existing ion milling apparatuses face the challenge of moisture condensation on samples when transitioning from a vacuum state to atmosphere, as the heating process causes evaporated moisture to re-adhere and condense, potentially damaging the sample.

Innovation Solution

A charged particle beam apparatus that includes a vacuum gauge to monitor pressure within the chamber, a dry gas inlet to introduce a moisture-free gas only when the pressure reaches a specific low level, and a heater to efficiently raise the sample temperature, preventing moisture condensation by maintaining a controlled vacuum environment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a gas is admitted into the vacuum chamber during heating, then the heating efficiency is improved, but moisture condensation occurs on the sample

Engineering Contradiction:
Improveheating efficiencyVSAvoidmoisture condensation
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The system performs preliminary evacuation to reach a target pressure level before admitting gas for heating. The control section monitors pressure via the vacuum gauge and only activates the gas inlet assembly when the pressure reaches below the given threshold, ensuring moisture is removed beforehand to prevent condensation during subsequent heating

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The control section uses feedback from the vacuum gauge to dynamically control the gas inlet assembly. The system continuously monitors pressure and adjusts gas admission timing based on real-time pressure readings, admitting gas only when pressure conditions are optimal to prevent moisture condensation while enabling efficient heating

Inventive Principle:
Principle #23Feedback

2Object-affected harmful factors

If the vacuum chamber is kept at high vacuum during heating, then moisture condensation is prevented, but heating time is extended

Engineering Contradiction:
Improvemoisture condensation preventionVSAvoidheating time
Core Design Contradiction:
Object-affected harmful factorsVSLoss of time

Solution Approach 1:

The system employs periodic action by alternating between evacuation phases and gas admission phases. During evacuation, pressure is reduced to prevent condensation; once target pressure is reached, gas is admitted for efficient heating. This periodic cycling optimizes both condensation prevention and heating speed

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The system changes the pressure parameter dynamically - maintaining high vacuum during critical phases to prevent condensation, then lowering pressure by admitting gas to enable efficient heat transfer. The control section manages these parameter transitions based on vacuum gauge readings to balance condensation prevention with heating efficiency

Inventive Principle:
Principle #35Parameter changes

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 solution effectively suppresses moisture condensation on samples and allows for rapid heating to room temperature, enhancing the efficiency of the ion milling process, especially for materials with low thermal conductivity like organic and polymer materials.

Implementation Method 1

a heater (6) that heats the sample holder (3)

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 2

an evacuation section (13) that vents gas in the interior space of the vacuum chamber (2)

Methodology Applied
Scientific EffectVacuum pumping: Pump

Implementation Method 3

a vacuum gauge (15) that measures the pressure in the interior space of the vacuum chamber (2)

Methodology Applied
Scientific EffectPressure measurement:

Implementation Method 4

a gas inlet assembly (14, 17, 19) that admits a dry gas containing no moisture into the interior space of the vacuum chamber (2)

Methodology Applied
Scientific EffectGas admission:

Data Source

PatentEP3664120B1Vacuum cooling apparatus, ion milling apparatus and method of operation
Publication Date: 2024.02.07 JEOL LTD
  • EP3664120B1 patent drawingFigure 1
  • EP3664120B1 patent drawingFigure 2
  • EP3664120B1 patent drawingFigure 3

AI summary

There is provided a vacuum cooling apparatus and ion milling apparatus capable of suppressing moisture condensation on a sample and of heating it in a short time. The ion milling apparatus (1) has a sample holder (3), a vacuum chamber (2), an evacuation section (13), a vacuum gauge (15), a heater (6), a gas inlet assembly (14, 17, 19), and a control section (10). The evacuation section (13) vents gas in the interior space of the vacuum chamber (2). The vacuum gauge (15) measures the pressure in the interior space of the vacuum chamber (2). The heater (6) heats the sample holder (3). The gas inlet assembly (14, 17, 19) admits a dry gas containing no moisture into the interior space of the vacuum chamber (2). When the pressure in the interior space has reached below a given pressure, the control section (10) controls the gas inlet assembly (14, 17, 19) based on information about the pressure in the interior space measured by the vacuum gauge (15) so as to admit the dry gas into the vacuum chamber (2).