Leak Testing Capsule Segmentation for Helium Adsorption
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Solution Overview
Problem
The accumulation method for leak testing of micro-sized electronic components faces challenges with helium adsorption to the chamber walls, leading to background and impurity gas interference, and rapid exhaust can result in undetectable helium, making it difficult to accurately calculate leak flow rates.
Innovation Solution
A leak testing apparatus with a capsule having a smaller inner capacity than the chamber, where the capsule is sealed during accumulation and then opened to release gas into the chamber for detection, allowing for reduced background and impurity gas interference and ensuring helium detection by maintaining a larger chamber volume for gas exhaustion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the chamber inner capacity is reduced to minimize adsorption of helium to chamber walls, then background and impurity gas interference is reduced, but the exhausted helium cannot be detected due to instantaneous exhaustion
Solution Approach 1:
The system is divided into two functional chambers: a first chamber (capsule) for accumulating leaked helium with small volume to minimize adsorption, and a second chamber (detection chamber) with larger volume to ensure detectable helium concentration during exhaust. This segmentation resolves the contradiction by separating the accumulation function from the detection function.
Solution Approach 2:
The first chamber acts as an intermediary accumulation vessel between the test workpiece and the second detection chamber. It temporarily stores the leaked helium and releases it into the second chamber, mediating between the need for minimal adsorption (small volume) and sufficient detection signal (large volume).
2Volume of stationary object
If the chamber inner capacity is increased to ensure exhaust time for detection, then helium detection is ensured, but background and impurity gas interference increases due to increased adsorption surface area
Solution Approach 1:
The detection system is segmented into two chambers where the first chamber (small volume) is dedicated to helium accumulation with minimal adsorption, while the second chamber (larger volume) provides sufficient exhaust time for detection. This segmentation allows each chamber to be optimized for its specific function without compromise.
Solution Approach 2:
Different chambers are given different volume characteristics suited to their local function: the first chamber has small volume to minimize adsorption surface area and background interference, while the second chamber has larger volume to ensure adequate exhaust time and detectable helium concentration. Each location has optimized quality for its purpose.
3Device complexity
If a single chamber is used for both accumulation and detection, then device complexity is reduced, but reliable detection of minute leaks cannot be achieved due to background gas interference
Solution Approach 1:
The system uses two separate chambers to segment the accumulation and detection functions, preventing background gas interference from compromising leak detection accuracy. The first chamber accumulates helium with minimal adsorption, while the second chamber performs detection with sufficient exhaust time, achieving high measurement precision.
Solution Approach 2:
The first chamber serves as an intermediary accumulation vessel that isolates the detection process from background gas interference. By separating the accumulation function from detection, it enables reliable detection of minute leaks while maintaining manageable device complexity.
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 configuration enhances the reliability of leak testing by minimizing background and impurity gas interference, allowing for accurate detection of minute leaks and improved sensitivity in leak flow rate calculations.
Implementation Method 1
gas in the chamber is evacuated
Implementation Method 2
helium in this exhaust is detected
Implementation Method 3
leaked helium from a test workpiece is accumulated in a chamber for a predetermined accumulation time, and helium partial pressure is increased
Implementation Method 4
the openable/closeable part is closed to seal the capsule
Data Source
AI summary
In leak testing by an accumulation method, it is possible to reliably detect accumulated inspection gas, and the reliability of leak testing is enhanced by reduction in background or impurity gas. At least an openable/closeable part 29 of a capsule 20 is housed inside a chamber 10 of a leak testing apparatus 1. A test workpiece 9 is housed in the capsule 20. Gas inside the chamber 10 is evacuated by a vacuum pump 31. A detector 2 detects inspection gas contained in this gas. The capsule 20 is continuously sealed for an accumulation time Ta, the capsule 20 is thereafter opened, and a leak is evaluated on the basis of detection information after the opening by the detector 2.