JP2006098274A - Probe pin for probe card - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a probe pin for a probe card, free from the existence of pin holes or defects on a plated surface, with a pointed end part prevented from oxidating, an electrode material prevented from sticking thereto, contact resistance stabilized, and slipperiness owing to contained polytetrafluoro-ethylene sufficiently improved, as to a probe pin for a probe card equipped with a taper part on one end part thereof, the taper part having the pointed end part (pinpoint portion) formed like a needlepoint. <P>SOLUTION: As to this probe pin 10 for a probe card equipped with the taper part 2 on one end part thereof, the taper part 2 having the pointed end part (pinpoint portion) 3 formed like a needlepoint, at least an end surface 3a of the pointed end part 3 is given polytetrafluoro-ethylene-containing plating of 3 to 10μm thickness. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to probe pins for probe cards (hereinafter abbreviated as “probe pins”) for conducting energization inspection of integrated circuit chips on a semiconductor wafer.

  Hard and elastic tungsten, rhenium tungsten, beryllium copper alloy, etc. are used as probe pins for conducting energization inspection (wafer test) of integrated circuit chips in the manufacturing process of semiconductor wafers. Tungsten having excellent wear and toughness is often used.

  Tungsten is excellent for wear resistance, elastic force, toughness, hardness, etc., so it is a suitable material for probe pins composed of extremely thin wires with a diameter of several tens of microns. Due to frictional heat and heat generated by contact resistance when energized in contact with the circuit electrodes, the tip temperature rises and oxidation proceeds, reacting with the aluminum deposited on the integrated circuit, and several Aluminum oxide is generated and adhered to the pin tip portion after 1000 to tens of thousands of contacts.

  When aluminum oxide adheres, the contact resistance of the surface of the pin tip portion increases, and the electrical conductivity is lowered to hinder the wafer test. Therefore, it is necessary to perform maintenance (cleaning) such as polishing the pin tip portion. Further, since the wafer test is interrupted during the cleaning process, there is a problem that the efficiency of the wafer test is deteriorated.

As one means for solving such problems, polytetrafluoroethylene (PTFE, trade name “Teflon”) having a thickness of 0.5 to 2 μm is formed on the end face of the tip as described in Patent Document 1. (Registered Trademark) "-containing Ni-plated probe pins have been developed. Although the probe pin described in Patent Document 1 can also achieve the purpose as described in the publication, it contains polytetrafluoroethylene-containing Ni. Since the thickness of the plating is too thin, it is difficult to form a uniform plating film, which causes many pinholes and defects on the plating surface, preventing oxidation, preventing adhesion of electrode materials, stabilizing contact resistance, and containing polytetrafluoroethylene. The problem that the slipperiness due to the cleaning is not sufficiently improved and the effect of reducing the number of cleanings (maintenance) cannot be expected. A.
JP 2001-74777 A

  The present invention is intended to solve the above-mentioned problems of the probe pin described in Patent Document 1. In order to form a uniform film having no pinholes or defects on the plating surface, the present invention It is characterized in that the thickness of the fluoroethylene-containing Ni plating (film) is increased to 3 to 10 μm.

  In order to achieve the above object, the present invention provides a probe pin for a probe card having a tapered portion with a pointed end portion (pin tip portion) formed in a needle tip shape at one end, and has a thickness on at least the end surface of the pointed portion. Is a means for solving the problem by applying a plating containing 3 to 10 μm of polytetrafluoroethylene.

  According to the present invention, the polytetrafluoroethylene-containing Ni plating is thickened to a thickness of 3 to 10 μm, so that the tip of the probe pin is prevented from being oxidized, and the sliding property and the contact resistance are stabilized by the contained polytetrafluoroethylene. In addition, effects such as prevention of adhesion of the electrode material to the tip portion can be obtained.

  In addition, Ni plating is applied to the base of the above polytetrafluoroethylene-containing plating to solve the problem. With this configuration, that is, by adopting a configuration in which Ni plating is applied to the base, it is possible to improve the adhesion of the polytetrafluoroethylene-containing plating.

Since the probe pin obtained by the present invention is Ni-based plating, the conductivity at the tip of the probe pin is good.
Moreover, since the thickness of the polytetrafluoroethylene-containing Ni plating is as thick as 3 to 10 μm, the slip property of the probe pin tip due to the contained polytetrafluoroethylene becomes extremely good, and adhesion of aluminum oxide can be almost completely prevented. Oxidation of the probe pin tip can be more effectively prevented.

Due to the above effect, the contact resistance of the probe pin tip can always be kept low and stable, and as a result, cleaning (maintenance) due to an increase in resistance becomes unnecessary.
Furthermore, since cleaning (maintenance) is unnecessary, time loss due to cleaning during probe inspection can be eliminated, and continuous probe inspection can be performed.

  Adhesion of polytetrafluoroethylene-containing Ni plating to the probe pin tip is improved by adopting a structure in which Ni plating is applied to the base of the polytetrafluoroethylene-containing plating, that is, a structure in which Ni is applied to the base. It becomes possible to make it.

Hereinafter, the present invention will be specifically described with reference to embodiments shown in the drawings.
FIG. 1 is a front view of the probe pin, FIG. 2 is an enlarged side sectional view showing an arrow A in FIG. 1, and FIG. 3 is a graph showing experimental results.

  1 and 2, reference numeral 10 indicates a probe pin. The probe pin 10 is provided on a printed wiring board (not shown) of a probe card for conducting an electrical current inspection of an integrated circuit chip on a semiconductor wafer. Hundred pieces are arranged, and the base material is made of W, Re-W, beryllium copper, palladium or palladium alloy, and is formed on the main body 1 and one end (front end side) of the main body 1. The linear taper-shaped portion 2 having a predetermined length and a pointed portion (pin tip portion) 3 formed at the pointed head of the linear taper-shaped portion 2 are formed. Here, when an example of the dimension of each of these parts is shown, the main body 1 has a wire diameter of 0.07 to 0.7 mm and a total length of 25 to 100 mm. The length of the linear tapered portion 2 is 0.3 mm to 6 mm, and an end face 3 a having a diameter of 0.02 mm or less is formed on the tip portion (pin tip portion) 3.

  A base Ni plating film 4 is formed on the entire surface of the main body 1 of the probe pin 10 processed into such a shape by electroplating.

  The probe pin 10 on which the base Ni plating film 4 is formed is then subjected to Teflon-containing Ni plating by polytetrafluoroethylene-containing Ni plating by a known plating method on the entire surface of the linear tapered portion 2 including the pointed portion 3. A film 5 is formed. Here, the polytetrafluoroethylene-containing Ni plating film 5 is set to have a thickness of 3 to 10 μm, which is thicker than that of the conventional example.

In the illustrated example, the entire surface of the main body 1 (base material) is covered with the Ni plating film 4, and the polytetrafluoroethylene-containing Ni plating film 5 is formed in a range from the tip 3 to the linear main body 1. ing.
The range of the polytetrafluoroethylene-containing Ni plating film 5 is not limited to the example illustrated above, and can be appropriately changed within a range that does not cover at least the tip 3 and the portion to be soldered to the printed wiring of the main body 1. .
That is, theoretically, the initial purpose can be achieved by forming the polytetrafluoroethylene-containing Ni plating (film) 5 only on the end surface 3a of the tip portion 3, but such an extremely small area can be achieved. Since it is technically very difficult to form the polytetrafluoroethylene-containing Ni plating (film) 5 only at the location, in the example shown in the drawing, the polytetrafluoroethylene within a range of about 5 mm is formed on the front end side of the main body 1. By applying the fluoroethylene-containing Ni plating, the polytetrafluoroethylene-containing Ni plating film 5 is formed on the end surface 3a of the tip 3.

  The Ni plating 4 is a base for the polytetrafluoroethylene-containing Ni plating 5 and is applied for the purpose of improving the solderability in the main body 1. However, the Ni plating 4 is not necessarily applied to the entire surface of the main body 1 at the same time. It is not necessary, and Ni plating may be separately applied to the base portion and the soldering portion of the polytetrafluoroethylene-containing Ni plating 5.

  As shown in FIG. 2, the probe pin 10 having the polytetrafluoroethylene-containing Ni plating film 5 is bent into a key shape as shown in FIG.

  In the probe pin 10 manufactured in the above-described process, the polytetrafluoroethylene-containing Ni plating film 5 formed on the end surface 3a of the tip portion 3 contains polytetrafluoroethylene particles. The polytetrafluoroethylene particles Acts to improve the slidability of the tip 3 of the probe pin 10 when contacting the integrated circuit chip, so that the slidability of the probe pin 10 is improved. The adhesion of aluminum is reduced, and the number of cleanings can be reduced and stable contact resistance can be maintained. At the same time, wear resistance is improved. In particular, by setting the thickness of the polytetrafluoroethylene-containing Ni plating film 5 to 3 to 10 μm, which is thicker than that of the conventional example, the wear resistance has been dramatically improved as compared with the conventional one. Next, this point will be described based on experimental data.

  Table 1 shows that the film thickness of the Ni plating containing polytetrafluoroethylene is 0 μm (conventional example 1), the film thickness is 2 μm (conventional example 2), the film thickness is 3 μm (example 1), and the film thickness is 5 μm (example). 2) and a probe pin having a film thickness of 8 μm (Example 3) (each probe pin has the shape shown in FIG. 1 and each part of each probe pin is formed in the same size within the above-mentioned dimensions) 3 shows the relationship between the contact resistance value (Ω) at the time of contact with the integrated circuit chip and the number of contacts, and the results of experiments in which three samples were subjected to experiments for each example.

  FIG. 3 is a graph of this, and shows the state of change between the number of contacts and the contact resistance value with the horizontal axis being the number of contacts (× 10000) and the vertical axis being the contact resistance value (Ω). A curve a in FIG. 3 shows the result of the experiment of the conventional example 1 (plotted average values of three samples, the same applies hereinafter), a curve b shows the experimental result of the conventional example 2, and the curve c shows the present invention. The experimental results of Example 1 are shown, curve d shows the experimental results of Example 2, and curve e shows the experimental results of Example 3.

From the experimental results shown in Table 1 and FIG. 3, the probe pin of the embodiment of the present invention increased the number of contacts compared to the conventional probe pin having a coating thickness of 0 μm to 2 μm of the polytetrafluoroethylene-containing Ni plating. It can also be read that the contact resistance value (Ω) is suppressed from increasing.
In the current practice, cleaning is performed on the assumption that the eye field of use has been reached when the contact resistance value reaches 2Ω. According to the experimental results shown in Table 1 and FIG. 3, the use field of the conventional probe pin having a coating thickness of 2 μm of the polytetrafluoroethylene-containing Ni plating is 20 × 10000 times, whereas polytetrafluoroethylene is used. In the probe pin of Example 1 of the present invention in which the film thickness of the Ni plating contained is 3 μm, it has been found that the number of cleanings can be reduced to about ½ so that the field of use is approximately 40 × 10000 times.
It will be clear from the experimental results shown in Table 1 and FIG. 3 that the number of cleanings can be further reduced when the film thickness of the polytetrafluoroethylene-containing Ni plating is further thicker than 3 μm.
In addition, as the film thickness of the polytetrafluoroethylene-containing Ni plating increases, the flexibility of the tip 3 disappears, and the possibility that the film peels off during use increases, and the product varies. It becomes easy. In the present invention, the upper limit of the thickness of the polytetrafluoroethylene-containing Ni-plated film 5 is set to 10 μm as a result of considering such technical matters. That is, the thickness of the polytetrafluoroethylene-containing Ni-plated film 5 is considered to be a practical upper limit of 10 μm.

  The fact that the number of cleanings described above can be reduced means that by increasing the thickness of the polytetrafluoroethylene-containing Ni plating film to 3 to 10 μm, a uniform film without pinholes and defects on the plating surface is formed. It is presumed that this is due to the prevention of oxidation, prevention of adhesion of electrode materials, stabilization of contact resistance, and improvement of slipperiness due to the contained polytetrafluoroethylene.

As described above, according to the present invention, it is possible to obtain a probe pin capable of dramatically reducing the number of times of cleaning, and as a result, it is possible to eliminate time loss due to cleaning at the time of probe inspection and perform continuous probe inspection. It becomes possible.
Further, when cleaning is performed, the tip 3 is slightly shaved, so it is desirable that the number of cleanings be as small as possible. Therefore, according to the present invention, the effect of prolonging the life of the probe pin can be obtained by reducing the number of cleanings.

It is a front view of a probe pin concerning one embodiment of the present invention. It is a sectional side view which expands and shows the A arrow part of FIG. It is a graph which shows an experimental result.

Explanation of symbols

1: Body part 2: Linearly tapered part 3: Pointed part 4: Ni plating (film)
5: Ni plating (film) containing polytetrafluoroethylene
10: Probe pin 3a: End face of the tip 3

Claims (2)

  In a probe pin for a probe card provided with a tapered portion at one end with a tapered end formed in a needle tip shape, polytetrafluoroethylene-containing plating is applied to at least an end surface of the pointed portion, and the polytetrafluoroethylene-containing plating A probe pin for a probe card having a thickness of 3 to 10 μm. 2. The probe pin for a probe card according to claim 1, wherein Ni is plated on the base of the polytetrafluoroethylene-containing plating.