JPH0353776B2 - - Google Patents

Description

[Detailed Description of the Invention] [Summary] When performing a performance test by enclosing an LSI or the like in a vacuum chamber and irradiating it with an electron beam, it is necessary to connect the tester and the LSI in a way that reduces the influence on the high-speed test signal waveform. and allows the testing machine to be installed outside the vacuum chamber.

[Industrial application field]

The present invention relates to a test device that performs a performance test by irradiating an item under test, such as an LSI, with an electron beam in a vacuum chamber. do. The present invention relates to a test device that reduces the influence on high-speed test signal waveforms.

In recent years, with the development of semiconductor technology, various ICs and LSIs have become available.
When testing the performance of LSIs, it is sometimes necessary to irradiate them with an electron beam.

In order to irradiate an LSI with an electron beam, it is necessary to encapsulate the LSI in a vacuum chamber, and to test its performance, a test signal is supplied to the LSI from the test equipment, and the results are received and judged. There is a need.

Since it is necessary to exchange high-speed signal waveforms with LSI, a connection method that can be vacuum-sealed and that reduces the impact on the transmission of high-speed signal waveforms is required.

[Conventional technology]

FIG. 4 is a diagram illustrating a conventional connection method.

Figure 4a shows a case 2, which forms a vacuum chamber together with a stand 8, and a cable 6 that connects the electron beam irradiation device 1, the test head 7 of the test device, and the socket 4 in which the LSI 3 is installed. .

Stage 5 connects LSI 3 to electron beam irradiation device 1
It is possible to move horizontally on the platform 8 in order to position it below. Therefore, the cable 6 must have a wiring length that covers the amount of movement of the stage 5.

A test signal sent from the test head 7 enters the vacuum chamber via the cable 6 and is supplied to the LSI 3 via the socket 4. The electron beam irradiation device 1 irradiates the LSI 3 with an electron beam. Further, the signal sent from the LSI 3 is sent to the test head 7 via the cable 6, and the quality of the LSI 3 is determined.

However, in the case of the conventional example shown in FIG. 4a, the wiring length of the cable 6 is long, so that distortion occurs in the high-speed signal waveform. Therefore, there was a problem that there was a limit to the performance test of LSI3.

For this reason, a connection method as shown in FIG. 4b was devised.

FIG. 4b shows a test head 7 with an LSI 3 mounted thereon directly enclosed in a vacuum chamber composed of a horizontally movable table 8 and a case 2 fixedly supported by a frame (not shown). Further, the electron beam irradiation device 1 is attached to the case 2 as in FIG. 4a. Note that the stand 8 and the case 2 are provided so as to be able to slide, and have a sealing material on the sliding surfaces.
A test signal is directly supplied from the test head 7 to the LSI 3.

[Problem that the invention seeks to solve]

However, in the case of the conventional example shown in FIG. 4b, since the test head 7 is enclosed in a vacuum chamber,
There are problems in that the volume of the vacuum chamber increases, the evacuation time becomes longer, and a mechanism for discharging the heat generated by the test head 7 to the outside is required.

In view of these problems, it is an object of the present invention to provide a connection method that can shorten the connection distance between the test head 7 and the LSI 3 and reduce the influence on the test signal waveform.

[Means for solving problems]

FIG. 1 is a diagram explaining the principle of the present invention.

In FIG. 1a, 1 is an electron beam irradiation device, which irradiates an LSI 3 with an electron beam, which will be described later, and 13 is a vacuum chamber, and a table 8, which will be described later.
, a case 2 that is slidable with respect to the stand 8, and a case 2 that is provided on the case 2 side between the stand 8 and the case 2;
3 is an LSI, which is one of the test objects, and is irradiated with an electron beam to perform a performance test.

4 is a socket into which the terminal of LSI 3 is inserted and connected; 7 is a test head, which is provided so as to be movable up and down with respect to the stand 8 by a moving device (not shown);
A drive signal is inputted through the electric wire 12 connecting the test head 7 and the socket 4, and the output in response to the drive signal is monitored to determine whether the LSI 3 is good or bad.

Reference numeral 8 denotes a stand, which is connected to an X-Y drive device (not shown) and is horizontally movable, and which sequentially changes the irradiation position of the electron beam from the electron beam irradiation device 1 on the LSI 3; This is a socket mounting stand, on which a socket 4 is mounted and an electric wire 12 for connecting the test head 7 and the socket 4 is housed therein.

10 is a storage case fixed to the test head 7, which connects the socket mounting base 9 to the test head 7 and maintains the airtightness of the vacuum chamber 13 by closing the gap between the socket mounting base 9 and the base 8; 11 is a vacuum seal member, and storage case 1
0 and the electric wire 12 in an airtight manner.

FIG. 1b is a sectional view taken along the line A-B in FIG. 1a,
As shown in the figure, the storage case 10 has a circular shape, for example, and the electric wires 12 sandwich the socket 4 and are arranged so as to be easily connected to the terminals of the socket 4.

The electric wire 12 connects the test head 7 and the socket 4 over a short distance, and the storage case 10 and the vacuum seal member 11 are configured to prevent air from entering the vacuum chamber 13.

[Effect]

With the configuration as described above, testing of LSI3 is performed as follows. First, vacuum chamber 1
Exhaust the air from step 3 using an exhaust device (not shown),
When a vacuum is created, a test signal is sent from the test head 7 to the terminal of the socket 4 via the electric wire 12.
Based on this test signal, the LSI 3 inserted into the socket 4 transmits the signal processed by the internal circuit to the electric wire 1.
2 and then sent to the test head 7.

Then, the test head 7 determines whether the LSI 3 operates normally or not based on the signal obtained via the electric wire 12. If an abnormal operation occurs, the electron beam irradiation device 1 is driven to detect the abnormal location in order to detect in which part of the LSI 3 the abnormality has occurred.

As explained above, the socket 4 is fixed to the test head 7, and there is no need for a wiring length corresponding to the moving distance of the table 8, and the connection distance of the electric wire 12 can be shortened, with almost no effect on the signal waveform. Since the test head 7 can be placed outside the vacuum chamber 13, it is possible to use a simple heat dissipation mechanism such as a fan.

〔Example〕

2 and 3 are schematic diagrams showing the configuration of a testing machine to which the connection method of the present invention is applied, FIG. 2 being a side view of the testing machine, and FIG. 3 being a plan view of the testing machine.

In the figure, 20 is an electron beam irradiation device, such as a scanning electron microscope (scanning electron microscope).
It consists of an electron microscope (SEM) electron gun and lens system.

21 is a vacuum chamber, an outer case 22,
A mounting table 23 on which the outer case 22 is placed, a moving table 24 supported by a known planar movement mechanism and provided so as to be horizontally movable relative to the mounting table 23 to a position indicated by a chain double-dashed line in the figure; O is a vacuum seal member that closes the space between the mounting table 23 and the moving table 24.
It is composed of a ring 25 and the like.

26 is a socket mounting stand, which is the test object.
A device that supports the socket into which the LSI is inserted,
Reference numeral 27 denotes a storage case, which houses the signal line (not shown) to be supplied to the socket, and also serves as a storage case for the mounting table 2.
A vacuum seal member (not shown) for keeping the interior of the case 22 airtight is provided on the outer peripheral surface, which is the sliding surface between the case 3 and the moving table 24.

Reference numeral 28 denotes a test head, to which a storage case 27 is integrally attached, and a signal line (not shown) is connected to the socket via the storage case 27. It supplies drive signals for performing various operations and determines the quality of the LSI based on the processed signals obtained from the LSI, and is provided so as to be movable up and down with respect to the movable table 24.

Reference numeral 29 is a motor which, by rotationally driving a screw 30, moves the nut 31 up and down to move the test head 28 fixed to the nut 31 up and down with respect to the movable table 24. Reference numeral 32 is a caster. , to make the casing 33 of the device movable.

34 is a TV camera supported by an arm 41, a storage case 27 positioned at the broken line position, and a device for recognizing the position of the LSI on the socket mounting base 26; 35 is an exhaust device; a hose 36; This is for evacuating the inside of the vacuum chamber 21 by discharging the air inside the vacuum chamber 21 through the vacuum chamber 21.

37 is a secondary electron detector, and optical fiber 3
7a, 37b, 37c, and 37d (the illustration of the middle part is omitted) to detect the secondary electrons emitted in multiple directions, and 38 is an energy analyzer, which has an electron beam passage hole in the center. It also has three stages of extremely fine wire mesh, which limits the amount of secondary electrons passing through.
39 is a diaphragm, which is used to regulate the amount of primary electrons.

In the configuration described above, first, the motor 29
By rotating the test head 28
At the same time, the storage case 27 and the socket mounting base 26 are moved downward, and the upper end is placed on the moving table 24.
Position it below the upper end surface of.

Thereafter, the moving table 24 is moved to the left in FIG. 2 by a planar moving mechanism (not shown), and the motor 29 is driven to position the storage case 27 at the position shown by the broken line.

Next, the operator inserts the LSI to be tested into the socket on the socket mounting base 26. The TV camera 34 shows the state in which the LSI is inserted into the socket.
The mounting position of the LSI on the socket mounting base 26 is detected from the imaging result. This detection result is stored in memory via a control device (not shown).

Thereafter, the test head 28 and the like are moved vertically and horizontally in the reverse order to the above order, and the storage case 27 and the socket mounting base 26 are positioned at the position shown by the solid line in FIG.

Next, the exhaust device 35 is driven, and the vacuum chamber 2
chamber 21 by discharging the air in chamber 21.
Make a vacuum inside.

In this state, the test head 28 is attached to the storage case 2.
inserted into the socket via the signal line inside 7.
In order to cause the LSI to perform various operations, a drive signal is supplied, and the signal processed by the internal circuit of the LSI is received to determine whether or not the LSI performs the desired operation.

If the determination result in the test head 28 is abnormal, first, a predetermined voltage (5V) is supplied to the LSI, and the scanning electron microscope 21 is driven to irradiate the LSI with an electron beam.

The secondary electrons at this time are transferred to the optical fibers 37a to 37.
Based on the detection result, a control device (not shown) determines whether or not a predetermined energy distribution is achieved, and detects a break or a short circuit in the pattern.

As explained above, in the present invention, since the test head is placed on a moving table, the wiring length for connecting the test head to the LSI under test can be shortened, and the signal waveform can be changed. The impact can be reduced.

In addition, since the test head is placed outside the vacuum chamber, the evacuation time inside the vacuum chamber can be shortened, and heat dissipation from the test head can be achieved by using air cooling such as a fan installed on the support base 40 that supports the test head. This makes it possible to employ an inexpensive and efficient heat dissipation mechanism.

〔Effect of the invention〕

As explained above, the present invention makes it possible to reduce the size of the vacuum chamber, enable test signals to be exchanged between the test machine and the product under test with almost no effect on the signal waveform, and facilitate heat dissipation from the test head. I can do it.

[Brief explanation of drawings]

FIG. 1 is a diagram explaining one embodiment of the present invention, and FIG.
The figure is a side view of the testing machine, Figure 3 is a plan view of the testing machine,
FIG. 4 is a diagram illustrating a conventional connection method. In the figure, 1 is an electron beam irradiation device, 2 is a case, 3 is an LSI, 4 is a socket, 5 is a stage,
6 is a cable, 7 is a test head, 8 is a stand, 9 is a socket mounting stand, 10 is a storage case, 11 is a vacuum seal, 12 is an electric wire, and 13 is a vacuum chamber.

Claims (1)

[Scope of Claims] 1. A mounting base 9 on which the object under test 3 is mounted, and a test head 7 that transmits a test signal for testing the object under test 3 and receives a response signal from the object under test. , a plurality of electric wires 12 for transmitting the test signal and the response signal, and a vacuum chamber 13 that accommodates the mounting base 9 and maintains the atmosphere of the test object 3 mounted on the mounting base 9 in a vacuum state. , the electric wire 12 is built in, and one end is connected to the test head 7.
a storage case 10 which is fixed to the vacuum chamber 13 and has a mounting base 9 fixed to the other end thereof; and an electron beam irradiation device 1 which is attached to the vacuum chamber 13 and which irradiates the test object 3 with an electron beam.
A part of the side wall of the vacuum chamber 13 is a movable table 8 that can be moved relative to the vacuum chamber 13 while maintaining airtightness, and the mounting table 9 is provided on the vacuum chamber side of the movable table 8. In order to arrange the storage case 10, the storage case 10 is airtightly attached to the moving table 8,
By sending a test signal from the test head 7 to the test object 3 via the electric wire 12, causing a response signal to be sent from the test object 3 to the test head 7 via the electric wire 12, and moving the movable table 8. , a test device characterized by adjusting the irradiation position of an electron beam.