JPS599535A - Method for testing airtightness of body - Google Patents

Abstract

PURPOSE:To perform the judgment of the large leak and the medium leak of a body with excellent reliability, by detecting the change in vacuum degree when the inside of an airtight container, wherein the body having an airtight chamber is enclosed, is evacuated. CONSTITUTION:A semiconductor device 1, which is sealed in a hollow package, is enclosed in a port 2. A leak valve 3 is closed, and the inside of the port 2 is evacuated by a vacuum pump 4. At this time, the temporal change of the vacuum degree is detected by a vacuum gage 5, and the result is displayed on a vacuum degree display device 6. The signal is further processed by a CPU7, and the vacuum degree characteristics are stored in a memory device 8. In the memory device 8, the vacuum degree characteristics for a perfect airtight body which has the same volume as that of the semiconductor 1, are stored. Said characteristics and the measured vacuum degree characteristics are compared, and the quality of the semiconductor device 1 is judged. Since a visual test is not performed, the judgment of the large leak and the medium leak can be performed with excellent reliability.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an airtightness test of an object having an airtight chamber, such as a ceramic packaged semiconductor device, and particularly to the field of gross leakage testing from a test level.

Conventionally, this type of test is conducted on a semiconductor device in which a semiconductor element is hermetically sealed in a hollow package by immersion in a high-temperature liquid called a bubble leak test, or by immersion in a high-temperature liquid after liquid pressurization called a gross leak test. There was an exam. Bubble leak test!・is 1~l X IQ
This is done to check for leakage of Torr lA.
A semiconductor device is immersed in a liquid at approximately 130°C, and as the gas pressure increases due to the expansion of the gas inside the airtight chamber, gas is blown out into the liquid from the microscopic holes in the package, and the presence or absence of bubbles is observed with the naked eye. It is used to judge the quality of the product.

A gross leak test is a test in which the semiconductor device is evacuated (1O-3 Torr according to the MIL standard) before the bubble leak test.
), then immersed in a liquid with a boiling point sufficiently lower than the liquid used for the bubble leak test, and then pressurized as it is to increase the detection sensitivity of the bubble leak test.
Sensitivity: 1 to 1 x 10”-6Torr l/s
It is said that If an airtight package has microholes, a liquid with a low boiling point is injected into the holes, and if the liquid is immersed in a liquid at 130° as in the bubble leak test, the injected liquid will Vaporization 11: Since the pressure change inside this airtight chamber is much larger than in the case of a bubble leak test, the detection sensitivity increases. Nao'I
'orr The unit of l/A is how many I leak in one second at a certain degree of vacuum.

However, when using the second method, humans visually check for the presence or absence of small bubbles that are generated when gas is blown out from microscopic holes in the airtight chamber, which can lead to oversights and reduce the reliability of the test. The drawback was that it got worse.

This invention was made in order to eliminate the drawbacks of the conventional method as described above, and the present invention was made in order to eliminate the drawbacks of the conventional method. By conducting the airtightness test of the object based on the above, there is no reduction in reliability due to oversights that occur in tests that rely on the naked eye, and the judgment of large and medium leaks called bubble leaks or gross leaks can be trusted. The purpose is to provide a method that can be used efficiently.

An embodiment of the present invention will be described below with reference to the drawings. 1st
In the figure, fi+ is a semiconductor device in which a semiconductor element is sealed in a hollow ceramic package and has an airtight chamber having a space of 0.1 d or more, and is an object to be tested for airtightness. (21 is a port of an airtight casing with a volume of 100 ffl or less for storing this conductor device (1) inside, and constitutes an airtight container. (3) is a port of an airtight case that stores the conductor device (1) inside. A leak valve (41) is attached to one end of the leak valve (3) and communicates with the opening on the side of the airtight container (2). ) is an airtight container (2)
a vacuum gauge that is attached to the opening of the vacuum gauge to detect the degree of vacuum and convert the signal to voltage, (61 is a vacuum degree indicator connected to this vacuum gauge (51 and displays the degree of vacuum, O that processes the signal from the vacuum gauge (5)
P There is.

” In a device configured as described in Section 2, the semiconductor device (
]) is accommodated in the port 1-121, and the inside of the boat (2) is evacuated by the vacuum pump 141 with the leak valve (3) closed. At this time, the degree of vacuum, which changes over time, is detected by a vacuum gauge (5), and this detected information is converted into a signal and displayed on a degree of vacuum indicator (6).

The signal is also sent to the OP U (71) and processed, and then inputted to the storage device (August 2011) and stored in the α
The vacuum characteristic indicated by υ is memorized. For example, as shown in FIG.
The vacuum characteristic shown by 121 is previously stored in the storage device (8) as a reference using the input device +91. These two stored vacuum degree characteristics are read out and a p U (
For example, the airtightness of the semiconductor device (11) is judged based on whether there is a difference in the degree of vacuum at a predetermined evacuation time t□, and the data and results are output to the output device port 0.
Output to . Since the airtightness test is performed based on changes in the degree of vacuum in this way, there is no visual test that is prone to errors as in conventional methods, making it possible to perform highly reliable tests.Also, since a computer is used, it is possible to perform airtightness tests based on changes in the degree of vacuum. reading/memory/
Comparison/output, input of other data, etc. can be performed immediately and accurately. Also, expensive leak test liquid is not required.

. In the above embodiment, the test was carried out based on the degree of vacuum after a predetermined time has elapsed, but for example, the time t at the characteristic 0'IJ based on the time t1 until reaching the predetermined degree of vacuum 1'0 shown in FIG. , o. In short, it may be a test in which the degree of vacuum characteristic (Ql) that changes as the evacuation time peaks is determined and compared with a standard (one) of the degree of vacuum characteristic.

Further, the comparison was made by the op U 171, but the change in the degree of vacuum outputted to the output device 001 may be read and compared, and the change in the degree of vacuum can be detected by the computer 0. ll
1, but the change in the degree of vacuum displayed on the display device 161 may be read and compared.

Furthermore, although the port (2) was evacuated using a vacuum pump, it may be evacuated using other evacuation equipment, or the evacuation conditions may be controlled by a control device using a computer or the like. When controlled, exhaust conditions can be kept more stable and test accuracy can be improved.

Furthermore, although one semiconductor device (1) was housed in the port (2) in the embodiment described in -, it is also possible to house a plurality of semiconductor devices at the same time. Ports may be provided and each port may be evacuated by one exhaust device to determine changes in the degree of vacuum. In this case, the throughput of the test can be improved.

Furthermore, in the above embodiment, the volume of port (2) is 100
d or less, the volume of the airtight chamber of the semiconductor device (1) is 0. 2 or more, that is, the volume ratio is smaller than 1000:1, but the present invention is not limited to this, and although the object to be tested is a semiconductor device, it goes without saying that the present invention is not limited to this.

Furthermore, in the above embodiment, the semiconductor device (11) is not pretreated, but it may be pressurized above atmospheric pressure in advance, or it may have the property of being vaporized by heating after being previously reduced to below atmospheric pressure. It may be pressurized to above atmospheric pressure in the liquid it holds, and changes in the degree of vacuum can be determined in a semiconductor device (11) at room temperature, but it may also be determined in a heated state; when heated, the volume of the gas expands. Therefore, test sensitivity can be improved.

In addition, in the above example, the change in the degree of vacuum was determined while the inside of port (2) was being evacuated. It may also be a change in the degree of vacuum.

As described above, according to the present invention, the airtightness test of the object having an airtight chamber is performed based on the change in the degree of vacuum in the airtight container when the airtight container in which the object is housed is evacuated. As a result, there is no need to visually check for bubbles in the liquid as in the past, so there is no risk of unreliability in the test due to overlooked bubbles, and it is possible to determine whether an object has a large leak or a medium leak with high reliability. effective.

[Brief explanation of drawings]

FIG. 1 is a conceptual diagram showing an embodiment of this invention, and FIG. 2 is a vacuum degree characteristic diagram for explaining this invention. In the figure, (1) is the object, (2) is the airtight container, and (4)
is an exhaust system. Agent Makoto Kuzuno - IQ+ Figure 1 Figure 2 Procedural amendment (voluntary) 21 Name of the invention Method for testing the airtightness of objects 3, Relationship to the case of the person making the amendment Patent applicant address 2-chome Marunouchi, Chiyoda-ku, Tokyo No. 2 and 3 Name (601) Mitsubishi Electric Co., Ltd. Representative: Katayuni Yabu 4, Agent address: 5, 2-2-3 Marunouchi, Chiyoda-ku, Tokyo Mitsubishi Electric Co., Ltd. Invention of the specification subject to amendment Column 6 of the detailed explanation of the amendment @ page 8, line 4 and line 18, ``180℃'' is corrected to ``125℃.''that's all

Claims (9)

[Claims] (1) An airtight container containing an object having an airtight chamber is evacuated by an exhaust device, and the airtightness of the object is tested based on a change in the degree of vacuum in the airtight container. Airtightness test method. (2) The airtightness test method for an object according to claim 1, wherein the airtightness test is performed based on a degree of vacuum corresponding to a predetermined evacuation time. (3) The airtightness test method for an object according to claim 1, wherein the airtightness test is performed based on an evacuation time corresponding to a predetermined degree of vacuum. (4) The method for testing the airtightness of an object according to claim 1, wherein the change in the degree of vacuum is output to a display means. (5) The method for testing the airtightness of an object according to claim 1, wherein the change in the degree of vacuum is converted into a signal and input into a storage device. (6) The airtightness testing method for an object according to claim 1, wherein the change in the degree of vacuum is compared with a reference. (7) The method for testing the airtightness of an object according to claim 6, wherein the reference is converted into a signal and input into a storage device. (8) The airtightness testing method according to claim 6, wherein the comparison is performed by a computer and output to an output device. (9) The ratio of the volume of the airtight container to the volume of the airtight chamber of the object is 10
A method for testing the airtightness of an object according to claim 1, wherein the airtightness is smaller than 00:1. 2. The method for testing the airtightness of an object according to claim 1, wherein the curved object is a semiconductor device.