JPH10213516A - Helium leakage detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a helium leakage detector capable of specifying accurate leakage quantity and leaking spot even if leakage from a tested body is of a large quantity. SOLUTION: A helium gas sensor 6 detectable of leakage quantity more than an ANAL 3 is provided on a rough drawing line L and leakage quantity and leakage spot are selectively detected by either the ANAL 3 or the helium gas sensor 6 depending upon the leakage quantity, therefore accurate leakage quantity and leakage spot can be detected even at the time of gross leakage test and leakage test can be effectively carried out regardless of the degree of leakage quantity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a helium leak detector used for performing a sealing inspection, a sealing inspection, and the like by a helium spraying method.

[0002]

2. Description of the Related Art A helium leak detector is one of the powerful means for performing a sealing test or a sealing test. As shown in a basic exhaust system diagram in FIG. 2, this helium leak detector is an oil rotary vacuum pump (RP) which is a roughing pump for roughing a test object W through a roughing line L.
2, a mass spectrometer (ANAL) 3 configured to select only helium (He) from the gas existing in the test object W and measure the amount thereof, and connected to the ANAL 3 High vacuum pump, turbo molecular pump (TM
P) 4). The test object W is detachably connected to the start end of the roughing line L so that the connection portion is airtight, and the connection portion is used as a test port (TP) 1.

[0003] More specifically, the roughing line L has a valve BV in the middle thereof and connects the intake port 2a of the RP2 at the end, and connects the first exhaust line L1 from the upstream portion of the valve BV. It has branched. This first exhaust line L1
Is connected to ANAL3 at the end via a valve TV on the way, and branches off the second exhaust line L2 from downstream of the valve TV. The second exhaust line L2 is
Having TMP4 on the line, wherein the TMP4
A downstream end of the roughing line L is communicated with an upstream portion of the RP2 through a valve FV.
The TMP 4 has an intake port 4a connected to the ANAL3 side and an exhaust port 4b connected to the intake port 2a of the RP2.
It operates while being backed up. In addition,
In the figure, reference numeral 5 denotes a vacuum gauge (PM) for detecting a vacuum value of the test object W during rough evacuation.

Next, a procedure of a leak test in the helium leak detector will be described based on a helium spraying method. First, the valves BV and TV are closed, and FV
Is opened to evacuate ANAL3. Next, the valve T
V and FV are closed, the valve BV is opened, the test object W is roughly exhausted by RP2, and after confirming that the inside of the test object W is evacuated to a high vacuum by PM5, the valve BV is closed and the valve FV is closed. , The TV is opened, and He is sprayed on the test object W. At this time, if there is a leak in the test object W, He leaking from the test object W is introduced into the ANAL 3 through the roughing line L and the first exhaust line L1, and based on the amount of the introduction. In addition, the amount and location of leakage from the test object W can be measured indirectly.

[0005]

However, in the case where the hermeticity or sealing state of the test object W is extremely poor, the leak amount of He exceeds the permissible value of ANAL3 and the leak amount cannot be detected accurately. Also, a large amount of He may be sucked into the ANAL 3 to attach He to the analysis tube, so that an accurate leak amount cannot be detected at the next test. Further, there is also a problem that the work efficiency is remarkably lowered due to interruption of a leak test or the like due to the work of removing He attached to the analysis tube of ANAL3.

[0006] Since there is a possibility of causing various problems as described above, when the amount of leak of He is large, the test object W cannot be connected to ANAL3, and H
Although it can be confirmed that e is leaking, there is a problem that the leak amount and the leak location cannot be specified.

[0007]

In order to solve the above-mentioned problems, a helium leak detector according to the present invention is provided with a gas sensor capable of detecting a leak amount larger than that of a mass spectrometer on a roughing line. And the gas sensor can selectively detect the amount of leakage according to the above.

In other words, the helium leak detector according to the present invention is designed such that, when a vacuum evacuation is performed on a device under test by a vacuum gauge or the like and the amount of leak is determined to be within an allowable value of the mass spectrometer, during rough evacuation. The test object is connected to the mass spectrometer with a part of the roughing line cut off, and the mass spectrometer detects the leak amount and the leak location. On the other hand, if it is determined that the DUT is not evacuated to a high vacuum and the leak amount exceeds the allowable value of the mass spectrometry unit, the DUT is not communicated with the mass spectrometry unit, and is placed on the roughing line. The amount and location of the leak are detected by the provided gas sensor.

Therefore, it is possible to effectively prevent the mass spectrometer from being contaminated with helium, to detect an accurate leak amount and a leak location even when the leak amount exceeds the allowable value of the mass spectrometer, and to perform a leak test. Can be performed effectively irrespective of the degree of the leak amount.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to a basic exhaust system diagram shown in FIG. Here, the explanation will be made based on the helium spraying method as in the conventional example, and the portions having the same structure as in FIG. 2 are given the same reference numerals. As shown in FIG. 1, the helium leak detector includes an oil rotary vacuum pump (RP) 2 as a roughing pump for roughing a test object W through a roughing line L, and a part of the roughing line L. A mass spectrometer (ANAL) 3 selectively connected to the test object W in a state where the pressure is shut off, and a turbo molecular pump (TMP) 4 as a high vacuum pump for evacuating the ANAL 3 and the test object W. It is made.

More specifically, the test object W is detachably attached to the starting end of the roughing line L so that a helium leak can be induced, and the test port (TP) 1 as a connection portion is mounted in an airtight state. Have been. The roughing line L is
It has a valve BV on its way, and the intake port 2 of RP2 at the end.
a, and the first exhaust line L1 is branched from the upstream portion of the valve BV.

The first exhaust line L1 is provided with a valve T
The second exhaust line L2 is branched from downstream of the valve TV by connecting the ANAL3 to the end through V. The second exhaust line L2 has a TM on the line.
P4, the end of which is connected to the downstream portion of the roughing line L from the TMP4 via a valve FV to the upstream portion of RP2 in the roughing line L. The TMP 4 has its inlet 4
a to the ANAL3 side, and the exhaust port 4b to the intake port 2a of RP2.
And operates while being backed up by RP2. In the drawing, reference numeral 5 denotes a vacuum gauge (PM) for detecting the vacuum value of the test object W during rough evacuation.

In this embodiment, a helium gas sensor 6 as a gas sensor is arranged on the roughing line L in this embodiment. The helium gas sensor 6 is a thermoelectric gas sensor that can detect a leak amount larger than that of ANAL3. Next, the procedure of the leak test in this embodiment will be described. First, the valves BV and TV are closed, the FV is opened, and the second
Exhaust line L2 is exhausted. The TMP4 operates while being backed up by the RP2, and evacuates the ANAL3 to a high vacuum. After confirming that a predetermined background value has been obtained in ANAL3, the test object W is set to TP1, the valves TV and FV are closed, the valve BV is opened, and the test object W is set through the roughing line L by RP2. The inside is roughly exhausted.

At the time of this rough evacuation, the inside of the test object W is in a high vacuum state due to PM5, and the leakage amount of He is ANAAL3.
Is determined to be within the allowable range, the valve BV is closed, the FV and the TV are opened, and He is blown from the spray pipe while the test object W is evacuated by the TMP4 and the RP2. As the vacuum evacuation of the test object W progresses, if there is a leak point in the test object W, He having high diffusibility is used.
Leaks into the test object W through the portion, the leaked He flows out of the roughing line L to the first exhaust line L1, and the leak amount and the leak location are detected by the ANAL3. Note that the above-mentioned spray tube sprays He on the entirety of the test object W while moving around the test object W. If the test object W has a crack, a pinhole, or the like, it is detected. The leak location can be specified by a sudden increase in the leak amount.

On the other hand, if it is determined by PM5 that the inside of the test object W does not reach a high vacuum and the leak amount of He is large, the valve BV is continuously opened and the RP2 is supplied through the roughing line L while the valve BV is opened. While evacuating, He is sprayed on the device under test W and H is detected by the helium gas sensor 6.
Identify the leak location and leak amount of e. Accordingly, in both the case where the leak amount is relatively small, or the case where the test device W has a very poor hermeticity and sealing state and the leak amount from the test object W is large, the ANAL 3 and the helium gas sensor 6 respectively A leak test can be performed effectively by accurately detecting a leak amount and a leak location regardless of the degree of the leak amount. Furthermore, the contamination of the ANAL3 by He can be effectively prevented, the problem of interrupting the leak test for removing He attached to the analysis tube of the ANAL3 can be eliminated, and the work efficiency of the leak test can be effectively improved.

The specific configuration of each part is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, if the helium gas sensor 6 and the vacuum gauge 5 are shared, the same function can be provided without adding a new sensor. In addition, H of RP2 is exhausted by exhausting a large amount of He.
In order to avoid e-contamination, when the leak amount is large, the inspection gas may be switched to argon, and the leak amount may be detected by an argon gas sensor.

[0017]

The present invention is embodied in the form described above and has the following effects. That is, the helium leak detector of the present invention arranges a gas sensor capable of detecting a leak amount larger than the mass analysis unit on the roughing line, and selectively detects the leak amount by the mass analysis unit or the gas sensor according to the leak amount. Because it is configured so that it is possible, the leak amount and leak location are accurately specified during the gross leak test, the leak test is performed effectively regardless of the leak amount, and the contamination of the mass spectrometer is effectively prevented. As a result, the work efficiency of the leak test can be effectively improved.

[Brief description of the drawings]

FIG. 1 is an exhaust system diagram showing one embodiment of the present invention.

FIG. 2 is an exhaust system diagram showing a conventional example.

[Explanation of symbols]

 2 rough pump (oil rotary vacuum pump; RP) 3 mass analyzer (ANAL) 4 high vacuum pump (turbo molecular pump; TMP) 6 gas sensor (helium gas sensor) L rough pump line W test object

Claims (1)

[Claims] 1. A roughing pump for roughing a device under test through a roughing line, a mass spectrometer selectively connected to the device under test while a part of the roughing line is cut off, A high vacuum pump for evacuating the mass spectrometer and the device under test, and a gas sensor capable of detecting a leak amount larger than the mass spectrometer on the roughing line. Helium leak detector.