JPH07239344A - Probe contact for inspection of vlsi - Google Patents

Abstract

PURPOSE:To form a probe contact to have a small diameter and correctly inspect a very-large-scale integrated circuit (VLSI) having a very small pitch, by using a minute ball obtained by holding a small ball between friction plates, sliding the friction plates to grind the small ball. CONSTITUTION:A coil spring 2 is set inside a trunk part 1 of an outer diameter of 0.2mm. Plunger contacts 3, 3' of a diameter of 0.14mm are fitted to the trunk part 1. Very small balls 4, 4' of a diameter of 0.13mm are inserted at parts where the plunger contacts 3, 3' are in touch with the spring 2. The very small balls 4, 4' are manufactured, for example, by holding a small ball 4a of a diameter of 0.5mm between friction plates 8 and 8', rotating the friction plates 8, 8' in the opposite directions and grinding the small ball 4a. The obtained very small ball has a diameter of 0.2mm or so. An abrasive material or fine powders of an abrasive material of a smaller diameter than that of the target balls 4, 4' are filled between the friction plates 8 and 8'.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultra-fine-diameter super LSI capable of performing a precise tri-inspection of a semiconductor such as an ultra-fine pitch interval, a disconnection of electrodes or patterns of liquid crystal or the like, or a short circuit. The present invention relates to a probe contact for inspection.

[0002]

2. Description of the Related Art A probe contact used for testing the circuit continuity of a printed circuit board is formed by fitting a plunger contact through a coil spring in a cylindrical body, and attaching the tip of the plunger contact. The plunger contact is configured to be movable relative to the body portion when is pressed against the surface to be measured of the printed circuit board.

Although there is no problem when the tip end contacts the surface to be measured perpendicularly and the coil spring is pressed straight, there is no problem when the tip end contacts the surface to be measured at an angle. If, for some reason, the coil spring is applied with an uneven force, the body and the sliding part of the plunger contact are momentarily separated, and as a result, current does not flow instantaneously. It is an obstacle to the exam. This is because when conducting a circuit continuity test or the like on a printed circuit board, a current must always flow normally through the probe contact itself. In particular, recently, the need for more precise tests is increasing, and thus there is a strong demand for probe contacts free from such defects.

In order to solve such a problem, a probe contact in which the lower surface of the sliding portion of the plunger contact is formed into an inclined surface and a small ball is interposed between the inclined surface and the coil spring is known in the United States. Has been proposed and already patented. In this probe contact, the slant surface of the sliding portion and the small sphere are in contact with each other, so that the sliding portion always receives a force for contacting the body portion, so that the contact is reliable. In recent years, the pitch of printed circuit boards to be inspected has become very narrow, so that there is a strong demand for a contact probe in which the tip of the plunger contact does not move from the center as much as possible. This is because even if the tip of the plunger contact moves even a little, the tip of the plunger contact may hit an unintended measured surface.

In order to prevent the tip of the plunger contact from moving as much as possible, it is necessary to make the plunger contact as thin as possible and to minimize the clearance between the plunger contact and the sleeve. However, in the conventional contact probe, since the currently available small balls are 0.5 mm or more,
There was a problem that the plunger contact could not be 0.7 mm or less.

[0006]

SUMMARY OF THE INVENTION The present invention intends to solve all of the above-mentioned conventional problems at once.
An object of the present invention is to provide a probe contact in which the plunger contact and the body can be stably contacted with each other and the probe contact itself has an extremely small diameter.

[0007]

In order to achieve the above object, the present inventor has conducted earnest research and, as a result, sandwiches a small ball between rubbing plates and slides the rubbing plate to polish the small balls. The present invention has succeeded in forming a plunger contact with a very small diameter by making it possible to manufacture a very small diameter small ball, and by using this very small diameter small ball. That is, according to the present invention, a plunger contact and a cylindrical body portion that slidably holds a sliding portion of the plunger contact, a coil spring installed in the body portion, the plunger contact and the coil spring are provided. And a microsphere interposed at a contact portion with the microsphere, the microsphere sandwiches a small ball between rubbing plates, and the rubbing plate is slid so that the small ball has a diameter of 0.4 mm to 0.05m
It is characterized by being ground into m microspheres.

[0008]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is a cross-sectional view showing an embodiment of the present invention, in which a body 1 having an outer diameter of 0.2 mm is internally provided with a coil spring 2 and a plunger contact 3 having a diameter of 0.14 mm.
An example is shown in which 3'is fitted into the body portion 1 and microspheres 4 and 4'having a diameter of 0.13 mm are provided at the contact portions of the plunger contacts 3 and 3'and the coil spring 2, respectively. FIG. 2 is a sectional view showing another embodiment of the present invention,
A coil spring 2 is internally provided in a body portion 1 having an outer diameter of 0.2 mm, and a plunger contact 3 having a diameter of 0.14 mm is fitted in the body portion 1 to bring the plunger contact 3 and the coil spring 2 into contact with each other. Each part has a diameter of 0.13
An example in which a mm microsphere 4 is interposed is shown. Plunger contacts 3 and 3'at the contact portion with the microspheres 4 and 4'are formed on the inclined surface to ensure the contact.

The conventional method for producing small spheres is to cut a round bar, put it in a small sphere mold, and press-mold it. In this method, fine spheres having a diameter of 0.5 mm or less are formed. It was impossible to manufacture. The microspheres used in the present invention are shown in FIG.
As shown in, between the rubbing plates 8 and 8 ', for example, a diameter of 0.5 m
The small sphere 4a of m is sandwiched, the rubbing plates 8 and 8'are rotated in opposite directions, and the small sphere 4a is polished to form a microsphere having a diameter of about 0.2 mm. Rubbing plate 8
And 8'contain an abrasive or a scraping plate 8
It is necessary to insert a fine powder of an abrasive having a diameter smaller than that of the microspheres to be manufactured between 8 and 8 '. As an abrasive,
For example, diamond, ceramic that can be used as an abrasive, or the like can be used.

The microspheres used in the present invention are preferably manufactured as shown in FIGS. 3 to 5 because of their ease of manufacture.
That is, as shown in FIG. 3, a steel wire rod 5 having a circular cross section with a diameter 20 to 30% larger than the diameter of the target microsphere is
As shown in FIG. 4, the tip is formed on the small ball portion 6 with a lathe, and then, as shown in FIG. 5, a cutter 9 is applied to the constricted portion 7 between the small ball portion 6 and the wire rod 5. Cutting, cutter-9
Has a slanted surface, the guided portion is guided by this slanted surface, and the constricted portion 7 is cut not in a straight line but in a curved line. As described above, the small spheres manufactured from the wire rod 5 having a diameter of 0.16 mm were used and polished as shown in FIG. 6 to obtain microspheres having a diameter of 0.13 mm.

An electron micrograph of the obtained microspheres (200
7) is shown in FIG. The linear portion on the horizontal side of FIG. 7 is hair, and three microspheres are imaged above it. From FIG.
It can be seen that the diameter of the microspheres obtained as described above is similar to the size of hair. According to the method shown in FIGS. Small spheres up to 05 mm can be obtained, and by using these fine spheres, a plunger contact with a diameter of 0.1 mm can be obtained. If the probe contacts with a diameter of 0.2 mm obtained as described above are arranged in a row, the terminals of the printed circuit board of the VLSI with 0.3 mm intervals can be inspected at the same time, and they can be arranged alternately or in a staggered manner. Can simultaneously inspect the terminals of the printed circuit board of VLSI with a terminal pitch of 0.08 mm.

[0012]

Using the probe contact of the present invention shown in FIG. 1, the change in resistance value was measured by the 2000-time probing test. The test was performed 5 times using different probe contacts. The results are shown in Table 1 below.
Incidentally, FIG. 7 shows the change in the resistance value after probing 1000 times in the first test.

[0013]

[Table-1]

From the results shown in Table 1 and FIG. 7, it can be seen that the probe contact of the present invention has very little change in resistance value after 2000 probing tests. This was far superior to the conventional probe contact via small balls, which was completely unexpected. It is considered that the contact was ensured by interposing a microsphere and forming a probe contact with an extremely small diameter.

[0015]

As described above, according to the present invention, it is possible to use the microspheres which cannot be manufactured conventionally.
Since the plunger contact can be made to have an ultrafine diameter, which has been considered impossible in the past, it is possible to extremely accurately inspect a super LSI having a very narrow pitch interval on a printed circuit board, and further, such an ultrafine diameter. By setting the diameter, a stable current always flows through the probe contact,
Therefore, this is an extremely epoch-making invention which has an unexpected effect that the test accuracy of the printed wiring board is dramatically improved.

[0016]

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is a sectional view showing another embodiment of the present invention.

FIG. 3 is a side view of a wire used to manufacture the microspheres of the present invention.

FIG. 4 is a side view showing a state where small balls are formed at the tip of the wire.

FIG. 5 is a side view showing a state in which a small ball at the tip is cut.

FIG. 6 is a cross-sectional view showing a state in which microspheres are manufactured by the method of the present invention.

FIG. 7 is an electron micrograph of microspheres obtained by the method of the present invention.

FIG. 8 is a diagram showing a change in resistance value by a continuous probing test using the probe contact of the present invention.

[Explanation of symbols]

 1 Body 3,3 'Plunger contact 4,4' Microsphere

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[Procedure amendment]

[Submission date] June 24, 1994

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Correction target item name] All drawings

[Correction method] Change

[Correction content]

[Figure 1]

[Fig. 2]

[Figure 3]

[Figure 4]

[Figure 5]

[Figure 6]

[Figure 7]

[Figure 8]

Claims (5)

[Claims] 1. A cylindrical body for slidably holding a plunger contact and a sliding portion of the plunger contact, a coil spring installed in the body, the plunger contact and the coil spring. Of the microspheres interposed between the rubbing plates, and the rubbing plates are slid so that the microspheres have a diameter of 0.4 mm to 0 mm. A probe contact for VLSI inspection, which is a microsphere ground to 0.05 mm. 2. The diameter of the microspheres is 0.2 mm to 0.05.
The probe contact according to claim 1, which is mm. 3. The diameter of the plunger contact is 0.
The probe contact according to claim 1, which has a length of 5 mm to 0.1 mm. 4. The probe contact according to claim 1, wherein the rubbing plate contains an abrasive, or fine particles of an abrasive having a diameter smaller than that of the microspheres are interposed between the rubbing plates. . 5. The small balls grind a wire having a circular cross section,
The probe contact according to claim 1, which is a small ball formed by forming a spherical tip and cutting the spherical object with a cutter.