JPH11160355A - Contact probe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a terminal metal from adhering, prevent deterioration, and transmit a signal, by covering an inner layer consisting of Ni group alloy at the needle tip of a contact pin with a conductive metal excluding a contact part for conduction. SOLUTION: When a contact probe with a contact pin 10 is placed on a probe card or the like and the needle tip of the pin 10 is brought into contact with a terminal 2 of a semiconductor IC chip 1, Au at the terminal 2 cannot adhere to a tip part 10a and hence adhesion phenomenon cannot be generated since the tip part 10a of the pin 10 that is brought into contact by the terminal 2 being made of Au is made of Ni-Mn alloy that is a different kind of metal with high hardness. However, a high-frequency signal being transmitted from the terminal 2 to the tip part 10a flows through a covering layer 12 that is constituted by Au that is the surface of the pin 10, thus minimizing the generation of noise due to the deterioration of signals. However, since the skin effect can be utilized, signals can be transmitted without any deterioration to cope with high-frequency signals.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a contact probe which is incorporated in a probe card or the like and performs an electrical test by contacting each terminal of a semiconductor IC chip or a liquid crystal device.

[0002]

2. Description of the Related Art In general, a contact probe provided with contact pins is used to make an electrical test by contacting a semiconductor chip such as an IC chip or an LSI chip or each terminal of an LCD (liquid crystal display). Can be For example, in the contact probe 30 shown in FIGS. 5 and 6,
A film layer 32 made of a polyimide resin or the like is laminated on a ground 31 made of a metal layer of Cu or the like, and Ni is formed on the film layer 32 via an adhesive layer 33 made of an adhesive.
Pattern wirings 34 made of a base alloy or the like are fixedly arranged. The distal ends of the pattern wirings 34 are arranged at a narrow pitch and protrude from the distal end of the film layer 32, and constitute the contact pins 3 respectively. This contact pin 3
A terminal of a semiconductor IC chip, a liquid crystal device, or the like is brought into contact with the needle tip.

[0003] Such a contact probe 30 is shown in FIG.
As shown in FIG. 8, a probe card (probe device) 36 is incorporated in the mechanical piece, and a terminal such as a semiconductor IC chip is brought into contact with the contact pin 3. That is, in the probe card 36 shown in FIGS. 7 and 8, the printed circuit board 3 having the central window 37a is provided.
For example, a top clamp 38 is attached on the top 7. Further, a base clamp 39 is fixed to a lower portion of the top clamp 38 with a bolt 40 or the like, and a tip side portion of the contact probe 30 is attached to a lower surface of the base clamp 39 with a double-sided tape or the like. By pressing the base of the contact probe 30 with the bottom clamp 41 having a substantially frame shape,
The distal end portion of the contact probe 30 is held in an inclined state, and the base is pressed against the lower surface of the printed circuit board 37 by the pressing rubber 42 of the bottom clamp 41. by this,
The rear end of the pattern wiring 34 of the contact probe 30 is pressed against the terminal on the lower surface of the printed circuit board 37 through the window 44 to be kept in a contact state. In such a state, the terminal 2 of the object to be inspected such as the semiconductor IC chip 1 is brought into contact with the contact pins 3 to perform an electrical test.

By the way, for example, as shown in FIG. 9, gold Au or solder Pb is used as the terminal 2 of the semiconductor IC chip 1.
In some cases, a metal such as -Sn is used. On the other hand, the contact pin 3 of the contact probe 30
It is necessary to prevent the deterioration of the high-frequency signal when conducting the test,
It is necessary to adopt a material having good conductivity. Ni-Mn alloys and the like usually used as the material of the contact pins 3 are as follows:
Although the hardness is high, the electrical resistance is large, so that the transmission signal is degraded at the time of energization and noise is easily generated, which is not preferable. Therefore, as shown in FIG.
An inner layer 4 is formed using an n-alloy, and the surface thereof is coated using Au to form a coating layer 5. When the contact pins 3 are brought into contact with the terminals 2 at the time of the test, a signal is transmitted between the terminals 2 and the contact pins 3 through the coating layer 5 having good conductivity.

[0005]

When an electrical test of the semiconductor IC chip 1 and the like is repeatedly performed using such a contact pin 3, the contact pin 3
A phenomenon occurs in which Au of the terminal 2 adheres to the tip of the substrate (this is referred to as an adhered portion 6) and grows gradually. For this reason, the adhering portions 6, 6 that have adhered to the tips of the respective contact pins 3 and grown by the plurality of adjacent contact pins 3, 3 are shown in FIG.
As shown in FIG. A similar problem occurs when a soft metal such as solder is used in addition to gold as the metal of the terminal 2.

The present invention has been made in view of the above circumstances, and provides a contact probe capable of preventing deterioration and transmitting a signal without attaching metal of a terminal to a current-carrying contact portion of a contact pin. The purpose is to do.

[0007]

Means for Solving the Problems In view of the above problems, the inventors of the present invention have made intensive studies and found that they are very soft, easily deformed plastically and very chemically stable, such as Au. Metals that have the property that a surface film is unlikely to be formed on the surface of a metal such as Au, even if they have a low contact force, form a new surface due to plastic deformation when they come into contact with each other, and contact occurs on this new surface. It was found that the sticking phenomenon occurred due to being touched. Therefore, on a contact surface between metals having the same conductivity, such as Au-Au, not only the energized state but also the phenomenon that the other metal easily adheres to one even without energization is observed. The present invention is based on such findings.

In the contact probe according to the present invention, a plurality of pattern wirings are formed on a film, and the tips of the pattern wirings project from the film to form contact pins. An inner layer made of a base alloy is covered with a conductive metal except for a current-carrying contact portion. When the energizing contact portion of the contact pin is brought into contact with a terminal of a device under test such as a semiconductor IC chip, the energizing contact portion comes into contact with a dissimilar metal because the Ni-based alloy is exposed, and the Ni-based alloy is hard. , The metal of the terminal can be prevented from adhering. In addition, since the contact pins are covered with a conductive metal such as Au on the portions other than the current-carrying contact portions, the conductivity is good, and since the skin effect can be used, the signal is transmitted without deterioration of the signal, and it is compatible with high frequencies. It is possible. Here, the conductive metal refers to a metal having good conductivity, being soft and easily deformable by plastic, and includes, for example, Au, Ag, and Cu.

Further, the contact probe according to the present invention comprises:
In a contact probe in which a plurality of pattern wirings are formed on a film, and the tips of the pattern wirings protrude from the film and become contact pins, the tips of the contact pins have an internal layer made of a Ni-based alloy having a platinum group metal. Characterized by being coated with Since the Ni-based alloy is not exposed at the current-carrying contact portion, contact failure due to oxidation of this portion does not occur. In addition, since the platinum group metal has a high hardness between the terminal and the dissimilar metal, there is no sticking phenomenon. In addition, the surface of the platinum group metal may be coated with a conductive metal except for the current-carrying contact portion. By contacting the terminal with the current-carrying contact portion made of a platinum group metal having high hardness, no sticking phenomenon occurs at the current-carrying contact portion, and the inside of the contact pin is covered with a conductive metal such as Au by a skin effect. Is transmitted.

[0010] The contact probe according to the present invention comprises:
In a contact probe in which a plurality of pattern wirings are formed on a film, and the tips of these pattern wirings protrude from the film and serve as contact pins, the tips of the contact pins are formed of an Ni-based alloy inner layer. The contact portion is coated with a platinum group metal, and the other portion is coated with a conductive metal such as Au. By contacting the terminal with the current-carrying contact portion made of a platinum group metal having high hardness, no sticking phenomenon occurs at the current-carrying contact portion, and the inside of the contact pin is covered with a conductive metal such as Au by a skin effect. Is transmitted.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a vertical cross-sectional view of a needle tip of a contact pin according to a first embodiment and I
It is a schematic explanatory view showing a C chip. In FIG. 1, at least the surface of a terminal 2 of a semiconductor IC chip 1 is made of Au. In FIG. 1, the terminals 2 are omitted except for one. The contact probe to which the contact pin according to the embodiment shown in FIG. 1 is attached has the same configuration as the contact probe 30 disclosed in the above-described prior art except for the contact pin portion. In the contact pin 10 shown in FIG. 1, the inner layer 11 is made of a Ni-based alloy because it is required to have high hardness and characteristics that are not easily plastically deformed. In the embodiment, for example, a Ni-Mn alloy containing 0.05 to 1.5 wt% of Mn is used as the Ni-based alloy. Here, if the Mn content is less than 0.05 wt%, Hv3
A hardness of 50 or more cannot be obtained, and the hardness may be extremely reduced by high-temperature heating. On the other hand, if the content exceeds 1.5 wt%, the stress at the tip portion increases, and there is a possibility that the tip portion may be curved, and it is very brittle and the toughness is reduced.
Note that a Ni-Co alloy or the like may be used as the Ni-based alloy.

At the tip of the contact pin 10, the tip of the inner layer 11 is exposed to the outside (terminal 2).
And a contact portion for energization, which is
At the tip 10a. Then, the surface of the inner layer 11 excluding the tip 10a is coated with highly conductive Au to form the first coating layer 12. Here, the tip 1 of the inner layer 11
The portion other than 0a was covered with Au because the Ni-Mn alloy has a large electric resistance and thus has a large loss as a signal transmission line, and the signal is deteriorated to generate noise. On the other hand, since a high-frequency signal generally has a characteristic of flowing on the surface of the contact pin 10 (referred to as a skin effect), deterioration of the signal can be prevented by coating the surface of the contact pin 10 with Au having good conductivity. .

Next, a method of manufacturing the contact pin 10 according to the above-described embodiment will be described. The process of manufacturing the contact pin 10 is the same as that disclosed in, for example, Japanese Patent Publication No. 7-82027. That is, a base metal layer is formed on a support substrate made of stainless steel by Cu plating. After a photoresist layer is formed on the base metal layer, the photoresist layer is exposed by applying a mask of a predetermined pattern, and the photoresist layer is developed to remove a portion that becomes a contact pin, and the remaining photoresist is removed. An opening is formed in the layer. Then, Ni-Mn is formed in the opening as a Ni-based alloy layer serving as the contact pin 10.
An alloy is formed by plating. Here, the inner layer 1 of the Ni—Mn alloy is formed only at the tip 10a of the contact pin 10.
As a method of exposing 1 and covering it with the first covering layer 12 of Au, a method of masking the tip portion 10a of the inner layer 11 of the manufactured contact pin 10 in advance and performing Au plating is used. Alternatively, a method in which the entire inner layer 11 of the contact pin 10 is covered with Au plating and the Au is peeled off only at the tip end portion 10a may be used, or any of them may be used.

As described above, according to the present embodiment, the contact probe having the contact pins 10 is mounted on the probe card 36 shown in FIGS. When the terminal 2 is brought into contact with the terminal 2 of the chip 1, the material of the terminal 2 is Au, whereas the tip 10 a of the contact pin 10 that is pressed and contacted by the terminal 2 is made of Ni—Mn, a dissimilar metal having high hardness. Since it is made of an alloy, Au of the terminal 2 does not adhere to the tip portion 10a, and the sticking phenomenon does not occur. In addition, since the high-frequency signal transmitted from the terminal 2 to the distal end portion 10a flows through the first coating layer 12 made of Au on the surface of the contact pin 10, generation of noise due to signal deterioration is minimized. be able to.

According to the above-described first embodiment, the above-described functions and effects can be obtained.
When the internal layer 11 of the Ni-Mn alloy is exposed at 0a, the Ni-Mn alloy is oxidized, and as a result, the electrical resistance at the time of contact increases, and a contact failure may occur. A second embodiment of the present invention to be described next improves such a problem, and will be described with reference to FIG.
The contact pin 14 shown in FIG. 2 includes an inner layer 11 made of a Ni—Mn alloy, which is entirely covered with a metal of a platinum group element, for example, platinum Pt, including a tip portion 14a.
Are formed. Here, platinum Pt has conductivity of Au.
Although it is inferior, it has a high hardness and is hardly oxidized.
It is possible to reliably prevent the adhesion phenomenon in which u adheres. still,
As the metal of the platinum group element used for the second coating layer 15, other than platinum Pt, Ru, Ph, Pd, Os, Ir, or the like can be used.

Next, a modification of the second embodiment will be described with reference to FIG. In FIG. 3, the contact pin 16
The second embodiment is that the second coating layer 15 is formed by coating the inner layer 11 made of an i-Mn alloy entirely with a platinum group metal, for example, platinum Pt, including the tip portion 16a. Is equivalent to the contact pin 14 of FIG. In the present modification, Au is formed as a conductive metal on the surface of the second coating layer 15 except for a tip portion 16a which is a contact portion for conducting with the terminal 2.
To form a third coating layer 18. According to this configuration, in addition to the effect of the second embodiment, even if the conductivity of the second coating layer 15 is inferior to that of Au, the signal transmitted from the terminal 2 to the tip portion 16a is conductive due to the skin effect. Since the third covering layer 18 made of Au having good properties is transmitted, there is an effect that the generation of noise due to signal deterioration can be reliably prevented.

Next, a third embodiment of the present invention will be described with reference to FIG. In FIG. 4, the contact pin 20
The inner layer 11 made of an i-Mn alloy is covered with a fourth covering layer 22 made of Au except for the tip 11a. In addition, the tip 20a of the contact pin 20 has an inner layer 1
The first tip 11a is coated with a platinum group metal, for example, platinum Pt to form a fifth coating layer 24. According to the present embodiment, the tip 20a of the contact pin 20 is made of platinum P.
t of the terminal 2,
Since u does not adhere to the tip 20a of the contact pin 20 due to the adhesion phenomenon, and since the surface of the inner layer 11 is covered with the fourth covering layer 22 made of Au except for the tip 20a, the signal is deteriorated. Can be reliably prevented.

The first coating layer 12, the third coating layer 18, and the fourth coating layer 22 that cover the inner layer 11 made of a Ni—Mn alloy are made of any material such as Ag or Cu instead of Au. You may comprise. Also, regarding the material of the terminal 2, Au
May be used instead of solder (Pb-Sn)

[0019]

As described above, in the contact probe according to the present invention, the tip of the contact pin has the inner layer made of the Ni-based alloy covered with the conductive metal except for the current-carrying contact portion. When the energizing contact portion of the contact pin is brought into contact with a gold or solder terminal of an object to be inspected such as a semiconductor IC chip or the like, the energizing contact portion comes into contact with a dissimilar metal,
In addition, since the Ni-based alloy has high hardness, it is possible to prevent the sticking phenomenon that the metal of the terminal adheres. Moreover, the contact pins
Since the portions other than the energizing contact portion are covered with a conductive metal such as Au, the conductivity is good, and since the skin effect can be used, the signal is transmitted without deterioration, and high-frequency operation is possible.

In the contact probe according to the present invention, since the inner layer made of the Ni-based alloy is coated with the metal of the platinum group element at the tip of the contact pin, contact failure due to oxidation of the current-carrying contact portion occurs. In addition, since the platinum group metal is a metal different from the terminal such as gold or solder and has a high hardness, the adhesion phenomenon does not occur. In addition, the surface of the platinum group metal may be coated with a conductive metal except for the energizing contact portion, so that the adhesion phenomenon does not occur in the energizing contact portion and the signal is not deteriorated by the skin effect. This has the effect of being transmitted.

In the contact probe according to the present invention, the tip of the contact pin has a current-carrying contact portion coated with a metal of a platinum group element in the inner layer made of a Ni-based alloy, and the other portions are made of Au or the like. Since it is covered with the conductive metal, no sticking phenomenon occurs in the current-carrying contact portion, and the signal is transmitted without deterioration of the signal due to the skin effect.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view showing a vertical cross section of a tip portion of a contact pin of a contact probe and a semiconductor IC chip according to a first embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of a needle tip portion of a contact pin according to a second embodiment of the present invention.

FIG. 3 is a longitudinal sectional view of a tip portion of a contact pin showing a modification of the second embodiment.

FIG. 4 is a longitudinal sectional view of a needle tip portion of a contact pin according to a third embodiment of the present invention.

FIG. 5 is a schematic plan view of a conventional contact probe.

6 is a partial vertical sectional view of a contact pin portion of the contact probe shown in FIG.

FIG. 7 is an exploded perspective view of a probe card to which the contact probe shown in FIGS. 5 and 6 is attached.

8 is a longitudinal sectional view showing a state where a contact probe of the probe card shown in FIG. 7 is mounted.

FIG. 9 is a longitudinal sectional view of a conventional contact pin and a semiconductor IC.
It is a schematic explanatory view showing a chip.

FIG. 10 is a view showing a state in which gold is stuck between needle tips of adjacent contact pins.

[Explanation of symbols]

 2 Terminal 10, 14, 16, 20 Contact pin 10a, 16a, 20a Tip 11 Internal layer 12 First coating layer 15 Second coating layer 18 Third coating layer 22 Fourth coating layer 24 Fifth coating layer 30 Contact probe

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Toshiho Ishii 12th-6th Technopark, Mita City, Hyogo Prefecture

Claims (4)

[Claims] 1. A contact probe in which a plurality of pattern wirings are formed on a film and each of the pattern wirings protrudes from the film to form a contact pin, and a tip of the contact pin is made of a Ni-based alloy. A contact probe, wherein an inner layer is coated with a conductive metal except for a contact portion for conducting electricity. 2. A contact probe in which a plurality of pattern wirings are formed on a film, and the tips of the pattern wirings protrude from the film to form contact pins, wherein the tips of the contact pins are made of a Ni-based alloy. A contact probe, wherein the inner layer is coated with a platinum group metal. 3. The contact probe according to claim 2, wherein a surface of the platinum group metal is coated with a conductive metal except for a current-carrying contact portion. 4. A contact probe in which a plurality of pattern wirings are formed on a film, and the tips of the pattern wirings protrude from the film to be contact pins, wherein the tips of the contact pins are made of a Ni-based alloy. A contact probe characterized in that, in the inner layer, a current-carrying contact portion is coated with a platinum group metal, and other portions are coated with a conductive metal.