JPH066443Y2 - Specimen mounting mechanism in electron beam prober - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Outline] Regarding a sample mounting mechanism in an electron beam prober, a distance between a sample to be tested and an IC tester is shortened so that signal transmission between them can be accurately performed, and For the purpose of facilitating the one-touch disconnection of the cable connecting the two, the IC sample mounted on the printed board in the vacuum chamber of the electron beam prober is connected to the outside of the vacuum chamber via the connection cable. In the sample mounting mechanism connected to the IC tester, a pair of contact probe groups that are brought into contact with the respective predetermined conductor patterns of the printed board and the IC tester are provided in a sealed cylindrical casing that holds the printed board. , A cable group having a pair of terminal pin groups, which can be inserted and removed in a plug-in manner, at both ends of each of the contact probe groups. A pair of cable holding plates, which are integrally held at regular intervals, are arranged to face the printed board and the IC tester.

[Industrial application field]

The present invention relates to an electron beam prober used for diagnosing an integrated circuit (IC) of a semiconductor device (inspecting the quality of circuit operation, etc.), and more particularly to a sample (IC) mounting mechanism thereof.

2. Description of the Related Art In recent years, the integration density of ICs in semiconductor devices has increased, and LSI (Large Scale Integrated Circuit) to VL
With the transition to the age of SI (Very Large Scale Integrated Circuit), the miniaturization of the pattern is remarkable.

Conventionally, the mechanical stylus method has been used as an IC diagnosis, but the spatial resolution is insufficient to be used for the diagnosis of a large-scale and high-density IC, and the pattern is damaged. It can no longer be applied.

Therefore, an electron beam prober using an electron beam probe has been developed and put into practical use as an alternative method for diagnosing a fine pattern. The principle of the electron beam prober itself is not directly related to the present invention, so a detailed explanation is omitted, but the details are described in Furukawa, Goto, Inagaki, "Electron beam probing exerting a powerful effect on LSI diagnosis", Nikkei. Electronics, March 15, 1982, p 172-
No. 201.

[Conventional technology]

Generally, an IC chip, which is a sample to be inspected, is placed in a vacuum chamber of an electron beam prober with an IC package mounted on a printed board to perform a desired diagnosis.

FIG. 5 shows the structure of a conventional sample mounting portion. In the figure, a tubular casing 23 is held in a housing 21 forming a vacuum chamber 20 via a sealing member such as an O-ring 6. An electron beam lens barrel 1 for irradiating an electron beam is attached to the upper part of the housing 21.
The electron beam from the electron beam column 1 irradiates the test IC chip of the sample 2 with the electron beam. At this time, 2 from the irradiated part
Since secondary electrons are emitted, by guiding them to an energy analyzer (not shown), it is possible to analyze the operation of the IC chip.

In the electron beam prober, since it is necessary to perform diagnosis while operating the IC, it is necessary to connect it to the IC (or LSI) tester 12 for sending power and drive signals (address signal, control signal, etc.) to the IC. . Therefore, the sample 2 is mounted on the disk-shaped printed board 3 and electrically connected to a group of connection lands (not shown) on the lower surface of the printed board through predetermined printed wiring and through holes (not shown). Connected. A large number of land portions are arranged on the lower surface of the printed board 3 in a circumferential shape, for example, at predetermined intervals, and the contact probes 4 are pressed against the land portions from below. In principle, there are as many contact probes 4 as the terminals of the IC chip, that is, the land portions, and the contact probes 4 are circumferentially penetrated and held by the disc-shaped holding plate 25 corresponding to the land portions. Incidentally, in FIG. 5, the contact probe 4 is shown in a double ring shape for the purpose of facilitating the understanding (the actual arrangement is 2
It can also be a heavy ring). The holding plate 25 is held and fixed to the shoulder portion of the casing 23.

A vacuum seal terminal plate 8 for sealing the vacuum chamber 20 from the outside is mounted in the casing 23 via an O-ring 7. A large number of male or female connectors 27a and 27b are formed on both surfaces of the vacuum seal terminal plate 8. A corresponding female or male connector (internal connector) 10 is detachably connected to one connector 27a. The internal connector 10 is connected to the above-mentioned contact probe group 4 via a cable 5.

The external connector 11 is detachably connected to the lower connector 27b in the same manner as the internal connector 10.
The external connector 11 is connected to the tester 12 via the external cable 9.
Is connected to the printed board 29.

Incidentally, the casing 23 is fixed to the tester 12, and the whole can be vertically moved integrally while sliding on the ring 6 by a stage system (not shown).

[Problems to be solved by the device]

As described above, since the IC tester 12 is placed outside the vacuum chamber, the vacuum seal terminal plate 8 that mediates the connection with the inside of the vacuum chamber is required. That is, in the conventional sample mounting structure, the sample 2 and the tester 12 are connected to each other by the connectors 10 and 11 of the cables 5 and 9 with the vacuum seal terminal plate 8 interposed therebetween. Therefore, it is necessary to give an extra length to the cable for inserting the connector, and the distance (interval) between the sample 2 and the tester 12, and thus the cables 5 and 9 tend to be long.

However, since the current flowing through the sample 2 is extremely small,
When the length of the cables 5 and 9 is long as described above, the signals are not accurately transmitted, and as a result, the operation analysis of the sample, the failure diagnosis, and the like cannot be performed accurately.

Further, the lengths of the cables 5 and 9 are naturally determined in consideration of impedance matching with the tester 12, but the cables 5 and 9 and the corresponding connectors 10 and 11 and the tester 12 (printed board 29 thereof) are Since the connection of each is done by soldering one by one, in the case of a single wire, the impedance between the cables is likely to be misaligned during the soldering work, and moreover, the cables may be changed in order to achieve impedance matching according to the specification change of the tester. In that case, the removal and reattachment work was very troublesome.

The purpose of the present invention is to eliminate such conventional problems.
The distance between the test sample and the IC tester is shortened so that signal transmission between the two can be accurately performed, and the cable connecting the both can be easily removed by a one-touch method. Especially.

[Means for Solving the Problems]

In order to achieve the above object, according to the sample mounting mechanism according to the present invention, a predetermined conductor pattern of each of the printed board and the IC tester is provided in a sealed cylindrical casing that holds the printed board on which the sample is mounted. A pair of contact probe groups that are brought into contact with each other, and a pair of cable pins that have a pair of terminal pin groups that can be plugged in and removed from each of the contact probe groups, are integrally held at predetermined intervals. The cable holding plate of each is a printed board and IC
The structural feature is that it is arranged so as to face the tester.

Also, preferably the cable group is formed by a group of coaxial cables.

[Action]

A pair of cable holding plates that hold a cable group having terminal pin groups at both ends form a cable module, and are connected and disconnected in module units. Moreover, the connection to the contact probe is made with a one-touch plug-in method. The conventional external connection cable is unnecessary, and the distance between the sample and the tester is shortened accordingly. In addition, the plug-in type one-touch connection can be easily installed and removed as many times as you like.

When the cable is a coaxial cable, noise between adjacent cables is reduced, and impedance matching is easily achieved.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail (first to fourth).
Figure). In the following embodiments, the parts corresponding to those shown in FIG.

In FIG. 1, the printed board 3 on which the sample (IC package) 2 is mounted is held on the cylindrical casing 23, and the contact probe 4 is brought into contact with the corresponding land portion from below the printed board 3 as shown in FIG. Is the same as that shown in. According to an embodiment of the present invention, the IC (or LS
I) For connection with the tester 12, a contact probe (second contact probe group) 14 exactly the same as the contact probe (first contact probe group) 4 is used instead of the external cable 9 shown in FIG. Therefore, as in the case of the printed board 3, the contact probe 14 is pressed against the contact land (not shown) of the predetermined pattern of the printed board 29 of the tester 12 and brought into contact therewith to complete the connection. The contact probe group 14 includes a holding plate (first
Like the holding plate 25, for example, a disc-shaped holding plate (second
It is penetrated and held by a holding plate) 26. The second holding plate 26 is fixed to the casing 23, and the casing itself is the tester 12
Since it is fixed to the side, it can move up and down with respect to the housing 21 by a stage system (not shown) while sliding on the whole of the O-ring 6.

The vacuum seal terminal plate 8 is attached to the casing 2 via the O-ring 7.
It is fixed to 3.

In the contact probes 4 and 14, a contact pin 43 is movably inserted into a conductor case 41 by a spring 45 (FIG. 3).

According to the embodiment of the present invention, both contact probe groups 4,
The connection between 14 is made by a one-touch type by a cable module. The cable module is basically formed by a pair of upper and lower cable holding plates 15 and 16 and a cable group 13 held between these cable holding plates. The cable group 13 has a group of cables arranged corresponding to the contact probe groups 4 and 14.

The cable 13 preferably has a certain degree of rigidity (for example, has a rigid outer cover), and functions as a spacer for maintaining the distance between the cable holding plates 15 and 16. Alternatively, separately from this, four columns as spacers may be provided between the cable holding plates 15 and 16 at intervals of 90 °, for example, although not particularly shown. In any case, the cable group 13
And the cable holding plate form an integrated module (unit).

The cable group 13 can be matched in impedance with the tester 12.

Terminal pins 48 (3a, 3b) are provided at both ends of each cable 13.
Figure) is integrally formed. The terminal pin 48 penetrates the respective cable holding plates 15 and 16 and extends to the outside, and is inserted into the conductor case 41 of the contact probes 4 and 14 and the socket 18b of the terminal 18 in a plug-in manner so as to be detachable.

In the conductor case 41 of the contact probes 4 and 14 and the socket 18b of the terminal 18, the terminal pins 48 and 18a are provided.
There is provided a contact 49 for holding the contact with a certain amount of force, that is, a force that does not allow it to come out freely. Instead of this contact 49, a spring contact 49 'as shown in FIG. 4 may be used.

As shown in FIG. 1, the contact probe 14 provided in the second holding plate 26 has exactly the same structure as the contact probe 4 shown in FIG. 3a, and the pin 18a of the terminal 18 provided on the vacuum seal terminal plate 8 is a conductor. It is inserted into the case 41. Further, the connection between the cable holding plate 16 and the vacuum seal terminal plate 8 is shown in Figure 3b. In this case, the terminal pin 48 of the cable holding plate 16 is inserted into the socket 18b of the terminal 18 of the vacuum seal terminal plate 8. still,
8a indicates a hermetic seal.

Each cable 13 has a large diameter portion 13a (third
Is formed, and not only functions as a positioning stopper for the cable holding plates 15 and 16, but also secures a bonding area (for example, an adhesive application area) to the cable holding plates 15 and 16. Alternatively, as shown in FIG. 1, the cable portion between both cable holding plates 15 and 16 can be uniformly made larger in diameter than the terminal pin.

The cable 13 is preferably a coaxial cable.
In the case of a coaxial cable, noise between the cables is reduced and each cable has a ground conductor (GND), so that impedance matching calculation is easy. In the case of the coaxial cable, the GND is connected to the large diameter portion 13a and dropped on the cable holding plates 15 and 16.

Often the specifications of the tester 12 are changed, but in that case, it is necessary to replace the cable between the cable holding plates and match the impedance accordingly. In such a case, according to the present invention, the entire cable module can be easily replaced. Further, for the same purpose, the vacuum seal terminal plate 8 and the tester 12 can be easily attached and detached. Further, in order to reduce the capacity of the vacuum chamber, the vacuum seal terminal plate 8 can be provided between the first holding plate 25 and the cable holding plate 15.

[Effect of device]

As described above, according to the present invention, by connecting the sample 2 and the tester 12 with the plug-in type one-touch and easily removable cable module, the cable length between the two can be shortened as compared with the conventional one. Therefore, signal transmission can be performed reliably and accurately.

Further, according to the present invention, when it is necessary to replace the cable for impedance matching or the like, the replacement work can be performed much easier than before.

Further, by forming the cable with a coaxial cable, noise between the cables is reduced and impedance matching is facilitated.

[Brief description of drawings]

FIG. 1 is a sectional view showing a sample mounting mechanism according to the present invention, and FIG.
FIG. 3 is a plan view of the cable holding plate shown in FIG.
FIGS. 3a and 3b are enlarged views showing details of a plug-in connecting portion to a contact probe pin, FIG. 4 is a view showing a modified embodiment of FIG. 3a, and FIG. 5 is a sectional view showing a conventional sample mounting mechanism. 2 ... Sample, 3 ... Printed board, 4, 14 ... Contact probe, 8 ... Vacuum seal terminal board, 12 ... Tester, 13 ... Cable, 15, 16 ... Cable holding board, 20 ... Vacuum Tank, 23 ... Casing.

Claims (2)

[Scope of utility model registration request] 1. A test sample (2) mounted on a printed board (3) in a vacuum chamber (20) of an electron beam prober.
Is a sample mounting mechanism for connecting a printed circuit board and a tester (12) outside the vacuum chamber via a connection cable, and a predetermined conductor for each of the printed circuit board and the tester is provided in a sealed cylindrical casing (23) for holding the printed circuit board. A cable group having a pair of contact probe groups (4, 14) that can be brought into contact with the pattern, and a pair of terminal pin groups (48) that can be plugged in and removed from each of the contact probe groups at both ends. A sample mounting mechanism in an electron beam prober, characterized in that a pair of cable holding plates (15, 16) for integrally holding (13) at a predetermined interval are arranged opposite to a printed board and an IC tester. 2. The sample mounting mechanism according to claim 1, wherein the cable group is formed by a group of coaxial cables.