JPS63182538A - Airtightness inspecting device - Google Patents

Abstract

PURPOSE:To inspect the airtightness of a body to be inspected by providing an air bubble catching part, a circulating flow means, and an air bubble detecting means. CONSTITUTION:The body 105 to be inspected which is put in the air bubble catching part 1 is dipped in liquid 103, which is sent to the circulating flow means 2 by a pump 114. The air bubble detecting means 3 is put in an operation state after air bubbles on the surface of the body 105 to be inspected are removed. At this time, when an air bubble is generated from the body 105 to be inspected, irradiation light 110 is scattered by the air bubble when passing through a transparent part 108. The quantity of photodetection varies greatly because the light is scattered more and more as the size of the air bubble is larger and larger, so that a pulse signal indicates the passage in the air bubble and the number of air bubbles. The pulse signal is counted 111 and the number of signals and signal intensity within a constant time are compared with reference values to make a decision 112, so that the result is displayed 113. The detecting operation is stopped and the pump 114 is also stopped; and the air bubble catching part 1 is elevated from the liquid 103 and the body 105 which is inspected a taken out. Consequently, the airtightness is grasped accurately, speedily, and quantitatively.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an airtightness testing device for testing the airtightness of a semiconductor device (tested object).

[Conventional technology]

2. Description of the Related Art Conventionally, there is an inspection apparatus that inspects the airtightness, which affects the quality of a semiconductor device, by immersing the semiconductor device in a fluid (testing liquid) and detecting air bubbles generated from the semiconductor device. In many of these types of inspection devices, air bubbles that float or float in the test liquid in the test tank are
This was an inspection device that irradiated light from a light source installed inside or outside the inspection tank, and detected the scattered light caused by air bubbles visually or with an optical detection mechanism such as a telephoto camera. Examples of such conventional airtightness testing devices include the following.

FIG. 4 is a schematic diagram of a conventional airtightness inspection device.

In the figure, 400 is a conventional inspection device, 401 is a test liquid tank, 402 is a heater, 403 is a test liquid, 404 is a mounting table, 405 is an object to be inspected, 406 is a camera tank, 407 is a bubble, and 408 is a TV camera. 409 is an optical detection means, 409 is an illumination means, 410 is a binarization section, 411 is a determination section, and 412 is a display section.

This conventional inspection device 400 was operated as follows. That is, the test liquid 403 in the test liquid tank 401 is heated to a predetermined temperature by the heater 402 . Next, test liquid 403
The object to be inspected 405 on the mounting table 404 is lowered and immersed therein, and air bubbles 407 generated and floating from the object to be inspected 405 are captured by the transparent bottom of the camera tank 406 . Then, while irradiating the captured bubbles 407 with light from the illumination means 409 outside the test liquid tank 401, the image captured by the optical detection means 408 of the television camera is displayed on the binarization section 410, determination section 411, and display section 412. Image processing, quality determination, and display of results were performed (Japanese Patent Laid-Open No. 148338/1983).

[Problem that the invention seeks to solve]

However, the conventional airtightness testing device has a drawback as explained with reference to FIG.

FIG. 5 is a diagram for explaining the shortcomings of the conventional inspection device, and 447 indicates outside air brought into the test liquid 403 together with the test object 405 when the test object 405 is immersed in the test liquid 403. bubbles.

In this conventional device, when the object to be inspected 405 is immersed in the test liquid 403, the surface of the object to be inspected 405, as shown in FIG.
In particular, many air bubbles 447 are generated on the lower surface. Since the test liquid 403 around the outside air bubbles 447 is only moving due to convection, the outside air bubbles 447 are removed from the test object 405 until the air bubbles 407 start to be generated from the test object 405 warmed by the test liquid 403. Bubbles 4 do not come off the surface of the object 405 and indicate the airtightness of the object 405 as shown in Figure (b).
After the generation of 07, the air bubbles 407 are mixed in with the air bubbles 407 and separated. If the air bubbles 447 from the outside air are mixed into the air bubbles 407 indicating airtightness in this way, it becomes a drawback that the accuracy of the measurement is reduced in quantitatively understanding the airtightness. Furthermore, if outside air bubbles 447 exist, this will determine the inspection limit, making it impossible to inspect a highly airtight inspected object.

Therefore, conventional inspection devices that detect air bubbles floating in the test liquid 403 are inaccurate and have low sensitivity.

The present invention was made in order to eliminate the above-mentioned conventional drawbacks, and an object of the present invention is to provide an airtightness testing device that can perform accurate and highly sensitive testing.

[Means for solving problems]

The airtightness testing device according to the present invention includes a bubble trapping section for taking in a test liquid in an area surrounding an object to be inspected, and a bubble capturing section that takes the bubbles and the test liquid out of a test liquid tank and into the test liquid. This airtightness testing device is equipped with a circulating flow means for discharging air into the air, and a bubble detection means for detecting air bubbles flowing through a circulation pipe of the circulating flow means.

[Effect]

In this invention, air bubbles generated from the test object are taken into the bubble trap together with the test liquid, and the taken-in test liquid is taken out of the test liquid tank by a circulating flow means and then returned to the test liquid tank. Since air bubbles generated from the object to be inspected are detected outside the test liquid tank, it is possible to eliminate the need to accurately test the airtightness of the object to be inspected.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic diagram of an airtightness testing device according to an embodiment of the present invention, and FIG. 2 is an enlarged cross-sectional view of a bubble trap in the testing device. In the figure, 100 is an airtightness inspection device, 101 is a test liquid tank, 102 is a heater, and 103 is a liquid such as Fluorinert or silicone injected into the test liquid tank 10.
With a test liquid such as oil, for example, 6
The temperature is raised to a predetermined temperature of 0 to 80°C. Reference numeral 105 indicates an object to be inspected, which is, for example, a semiconductor device in a dual-in-line package; 107, air bubbles generated from the object to be inspected 105; 227, air bubbles from outside air; and 108, a circulation vibrator 115 (
(described later) is a light-transmitting part of a flat tube made of transparent glass, for example, and when a plurality of bubbles 107 flow together with the test liquid 103 in this light-transmitting part 108, each bubble 107 is dispersed as much as possible. In order to accurately count the number of bubbles 107 by the optical detection unit 109 and the counting unit 111, at least the portion corresponding to the irradiation optical path from the illumination unit 110 has a flat cross-sectional shape, for example. 109 is an optical detection unit using, for example, a photomultiplier; 110 is an illumination unit that collects light from an incandescent lamp and irradiates it toward the light-transmitting unit 108; and 111 is an optical detection unit that uses a photomultiplier. a counting unit that counts the number according to the output signal of the optical detection unit 109;
Reference numeral 12 denotes a determining unit that determines whether the airtightness of the object to be inspected 105 is good or bad based on the counting result of the counting unit 111 and the output signal intensity, and 113 is a display unit that outputs the inspection results to a display or the like.

114 is a circulation pump, 115 is a circulation pipe, and out of all the parts of the circulation pipe 115, at least the part necessary for the operation of submerging the connected bubble trap 1 into the test liquid 103 is made such that the operation is not hindered. For example, plastic
It is made flexible by using a tube. 11
6 is the discharge port at the end of the circulation pipe 115, and the discharge port 1
The position below the surface of the test liquid 103 in No. 16 is shallower than the uppermost position h2 of the bubble trap 1 submerged in the test liquid 103.
(h+ <112) is arranged. ■ has an opening at one end through which the object to be inspected 105 can be taken in and taken out;
a bubble trap that accommodates and is submerged in the test liquid 103;
is connected to one end of the bubble trap 1 to take out the test liquid 103 in the bubble trap 1 together with the bubbles 107 out of the test liquid tank 101 and return it into the test liquid tank 101 through the discharge port 116.
Circulation pump 114, circulation pipe 115, and transparent section 10
8 is a circulating flow means, and 3 is a bubble detection means provided in the middle of the circulation pipe 115 and consisting of an optical detection section 109, an illumination section 110, a counting section 111, a determination section 112, and a display section 113. .

Note that the shape of the bubble trap 1 and the arrangement of the object to be inspected 105 in this embodiment are such that when the object to be inspected 105 is a semiconductor device such as a dual-in-line package as shown in FIG. Test liquid 103 flowing in section l
The shape and arrangement are illustrated so that the flow rate flows over the surface of the object to be inspected 105 with minimal stagnation.

Next, the operation of this airtightness testing device 100 will be explained using FIG. 1 and FIG. 2.

First, the detection operation of the bubble detection means 3 is stopped, and the object to be inspected 105 is put into the bubble trapping section 1, and the test liquid 10
3, the inside of the bubble trap 1 is filled with the test liquid 103, and the test object 105 is immersed in the test liquid 103.

Then, the circulation pump 114 is driven to draw the test liquid 103 in the bubble trap 1 into the circulation flow means 2 through the circulation pipe 115.

At this time, as shown in FIG.
is separated as the test liquid 103 moves within the bubble trap 1,
It is carried away toward the circulating flow means 2 together with the test liquid 103.

At this time, to completely remove air bubbles from the outside air, test liquid 103
The test object 105 is heated by the test liquid 103 flowing until the test object 105 reaches a predetermined temperature due to heat received from the test object 105.
The circulating flow mechanism 2 may be set so that the flow rate of the test liquid 103 is sufficient to wipe the surface. Among the outside air bubbles generated in the air bubble trapping section 1 as a result, outside air bubbles 227 are located at the location where the test liquid 103 moves toward the circulating flow means.
Needless to say, the flowing test liquid 103 easily removes the outside air bubbles 227 that were generated in large numbers on the lower surface of the test object 105. These are the transparent parts 10
8 together with the test liquid 103, the bubble detection means 3 is in a state where its detection operation is stopped, so that no detection is made.

Next, after a preset period of time has elapsed from the flow rate of the test liquid 103 that can completely wipe out air bubbles on the surface of the test object 105 and the time when the test object 105 reaches the same predetermined temperature as the test liquid 103, After the air bubbles 227 are completely removed,
The bubble detection means 3 is put into a detection operation state.

In this state, if a bubble 107 is generated from the object 105 to be inspected, the light emitted from the illumination section 110 will be scattered by the bubble 107 when the bubble 107 passes through the transparent section 108 . In this scattering phenomenon, the larger the size of the bubble, the more it is scattered, and the amount of light received by the light detection unit 109 changes greatly. That is, the temporal change in the amount of light received, specifically, the pulse signal indicates that the bubble 107 has passed, the number of pulse signals indicates the number of bubbles 107, and the pulse signal intensity indicates the size of the bubble 107. Then, the counting unit 111 counts the number of pulse signals B corresponding to the number of bubbles 107, and based on the number of pulse signals and the pulse signal strength within a predetermined measurement time, the determining unit 112 determines the confidentiality of the inspected object 105, which is preset. Judging pass/fail based on the criteria. Then, the test results are displayed on the display unit 113, printed, etc.

When the above operations are completed, the detection operation of the air bubble detection means 3 is returned to the stopped state, the circulation pump 114 is stopped, the air bubble trapping part 1 is pulled out from the test liquid 103, the object to be inspected 105 is taken out, and the airtightness is The operation of the inspection device 100 ends.

In this example, after completely removing air bubbles from the outside air on the surface of the object to be inspected, only the air bubbles truly generated from the object to be inspected can be detected, and the airtightness can be quantitatively determined accurately and quickly. At the same time, the inspection limit is expanded, and even objects with high airtightness can be inspected.

Further, the air bubbles discharged from the discharge port 116 are
Since the position below the surface of the test liquid 103 is placed shallower than the bubble trapping section 1, the test liquid 103 does not enter the bubble trapping section 1 again.
Accurate inspection can be performed.

In addition, since air bubbles are detected outside the test liquid tank, there are fewer restrictions on the geometric structure of the illumination means and optical detection means, which take into consideration air bubbles that move only upwards, as in the past, and the irradiation unit and Since the size, shape, and type of the optical detection part are more arbitrary, and the optical path can be simplified, it is easier to provide uniform illumination to the bubbles, increasing the accuracy of inspection.

FIG. 3 is a schematic diagram of an airtightness testing device according to another embodiment of the present invention. In the figure, 300 is an airtightness inspection device;
01 is an auxiliary heater provided between the circulation pump 114 and the discharge port 116. This auxiliary heater 301 is used to heat the test liquid 103 whose temperature has been lowered by passing through the circulation pipe 115 to a predetermined temperature, and then return it to the test liquid tank 101 through the discharge port 116 .

In this embodiment, by providing an auxiliary heater, the test liquid discharged from the circulation pipe is always kept at a predetermined temperature while the airtightness test is being performed, so that the test liquid 103 in the bubble trapping section 1 is always kept at a predetermined temperature. This allows the temperature to be maintained at a predetermined level, allowing for more accurate and rapid testing.

〔Effect of the invention〕

As described in detail above, according to the airtightness testing device according to the present invention, the test liquid in the area surrounding the object to be inspected is taken into the bubble trapping section, and the taken test liquid is transferred to the outside of the test liquid tank by the circulating flow means. After taking it out, it is returned to the test liquid tank, and the air bubbles generated from the test object are detected outside the test tank, so it is possible to truly detect the air bubbles generated from the test object. The airtightness of the object to be inspected can be quantitatively determined accurately and quickly, and the optical path can be simplified.

[Brief explanation of the drawing]

1 and 3 are schematic diagrams of an airtightness inspection device according to an embodiment of the present invention, FIG. 2 is an enlarged sectional view showing an example of a bubble trap used in the present invention, and FIG. 4 is a conventional airtightness inspection device. FIG. 5, a schematic diagram of the inspection device, is a diagram for explaining the drawbacks of the conventional device. In the figure, 100 and 300 are the airtightness testing apparatus of the present invention, 101 is a test liquid tank, 102 is a heater, 103 is a test liquid, 105 is an object to be inspected, 107 is a bubble, 108 is a transparent part,
109 is an optical detection unit, 110 is an illumination unit, 111 is a counting unit, 112 is a determination unit, 113 is a display unit, 114 is a circulation pump, 115 is a circulation pipe, 116 is an outlet, 301 is an auxiliary heater, 1 is an air bubble trap 2 is a circulating flow means, and 3 is a bubble detection means. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (3)

[Claims] (1) In an airtightness testing device that tests the airtightness of a test object by immersing the test object in a test liquid in a test liquid tank and detecting air bubbles generated from the test object, the test object a bubble trapping section that takes in the test liquid in an area surrounding the bubble trapping section, and a circulation for taking out the bubbles and the test liquid taken in by the bubble trapping section to the outside of the test liquid tank and discharging them into the test liquid above the bubble trapping section. An airtightness testing device comprising: a circulation flow means having a pump and a circulation pipe; and a bubble detection means provided in the middle of the circulation pipe to detect air bubbles flowing in the pipe. (2) The air-tightness according to claim 1, wherein the bubble trapping section has a shape such that the test liquid flowing in the bubble trapping section flows on the surface of the test object with minimum stagnation. Sex testing device. (3) The circulation pipe of the circulation flow means is equipped with an auxiliary heater for raising the temperature of the test liquid to a predetermined temperature on the discharge side of the bubble detection means, the airtightness according to claim 1. Sex testing device.