JP2003167003A - Probe needle for probe card - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a probe needle for a probe card provided with a plating containing PTFE excellent in abrasion resistance, let alone to prevent an oxidation on the surface of the tip of the probe needle and adhesion of aluminum oxide. <P>SOLUTION: A Ni-B plated layer 3 is formed at the tip of a probe needle 1 over an underlying Ni plated layer 2. Since the probe needle 1 is coated with the Ni-B plated layer 3 containing PTFE at the tip, electrical conductivity is good, the oxidation at an end face and adhesion of aluminum oxide are prevented, and stable conductivity can be retained. Furthermore, abrasion of the plated layer can be reduced to be lesser and the number of contact can be increased to a large extent. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a probe needle for a probe card, which is used for inspecting the electric conduction of an integrated circuit chip on a semiconductor wafer.

[0002]

2. Description of the Related Art Dozens to hundreds of probe needles for a probe card for conducting electric current inspection (wafer test) of integrated circuit chips in a semiconductor wafer manufacturing process are arranged on a printed wiring board (not shown). As the material, hard and elastic tungsten, rhenium tungsten, beryllium copper, etc. are used as the material, and in particular, tungsten having excellent wear resistance and toughness is widely used. . However, although tungsten is a material suitable for a probe needle that is excellent in wear resistance, elasticity, hardness, etc., has a toughness, and is composed of a thin wire rod with a diameter of several tens of microns, it easily oxidizes and is used as a probe needle. Oxidation proceeds as the temperature at the tip rises due to frictional heat when contacting the electrodes of the integrated circuit and current is applied, and heat generated by contact resistance, and reacts with aluminum deposited on the integrated circuit several thousand times. After a few tens of thousands of contacts, aluminum oxide is generated and attached to the tip of the needle.

When the tip portion of the probe needle is oxidized and aluminum oxide is attached in this manner, the contact resistance on the surface of the needle tip portion is increased and the conductivity is lowered to hinder the wafer test. It is necessary to perform maintenance such as polishing. Conventionally, this maintenance is normally performed once every several thousand to tens of thousands of contacts, depending on the usage status, which has been a problem in the wafer test performed automatically.

As a method for improving the oxidation resistance in order to solve these problems, for example, JP-A-11-380 is used.
As disclosed in Japanese Patent Laid-Open No. 39, a method of joining a non-oxidizing metal such as gold, platinum or palladium to the tip of a probe needle can be considered, and these non-oxidizing metals are more wear resistant than tungsten. Since it is poor in resistance and the bonding itself is difficult, a non-oxidizing metal film is formed on the tip of the probe needle by metallization such as electroplating, and then heated in a non-oxidizing atmosphere or in a vacuum to non-oxidize. By diffusing into tungsten, which is the base material of the functional metal,
A method of modifying the probe body into a probe needle having excellent oxidation resistance and conductivity while maintaining the wear resistance and toughness of the tungsten body has been considered.

However, any of the above methods is not practical in terms of cost and work, and the adhesion of aluminum oxide cannot be prevented.

In view of the above-mentioned problems, the present applicant has previously made a Ni plating containing PTFE (polytetrafluoroethylene) at the tip to prevent the oxidation of the surface of the tip and the adhesion of aluminum oxide. PTFE
A probe needle for a probe card plated with nickel containing Ni has been proposed (JP 2001-74777 A: hereinafter referred to as prior invention).

According to the above invention of the prior application, the conductivity is maintained even after 300,000 to 500,000 contacts, as compared with the conventional product, which requires maintenance such as polishing once every thousands to tens of thousands of contacts. It did not decrease, and the number of maintenances and the time required therefor could be significantly reduced.

[0008] However, the inventors of the present invention have not been satisfied with the number of contacts of 300,000 to 500,000 times, and as a result of earnest studies for further improvement of the number of contacts, the result of PTFE
The present invention has been accomplished by finding that the wear resistance of the contained Ni plating layer greatly affects the number of contacts.

That is, although aluminum is vapor-deposited on the integrated circuit, the outermost surface thereof is covered with aluminum oxide. In this state, even if the probe needle is contacted and a current test is performed, the inspection accuracy will vary.
It is necessary to remove the oxide scale layer on the surface by sliding in the surface direction with the probe needle in contact. At this time, the scraped-off aluminum oxide drops off without adhering to the probe needle tip portion due to the sliding effect of PTFE contained in the Ni plating, whereas the Ni plating layer has a Vickers hardness of Hv250-300. Since aluminum oxide has a very high Hv of 1000 to 2000, the Ni plating layer is gradually worn by the scraped aluminum oxide. When the Ni plating layer is worn, the slipperiness is reduced, and aluminum oxide is deposited on the probe needle surface, resulting in reduced conductivity.

Accordingly, the present invention provides a probe needle for a probe card having a PTFE-containing plating excellent in wear resistance as well as preventing oxidation of the tip surface of the probe needle and adhesion of aluminum oxide. The task is to do.

[0011]

According to the present invention, at least the end surface of the tip of the probe needle for a probe card is made of PTFE.
The above problem can be solved by covering with any one of Ni-B plating containing PTFE, Ni-W plating containing PTFE, or Ni-P plating containing PTFE aged (hereinafter referred to as "various PTFE-containing plating"). is there.

The end face of the tip of the probe needle has the above-mentioned various PTs.
When covered with FE-containing plating, it has good conductivity,
In addition, the oxidation of the end surface in contact with the integrated circuit is prevented, the sliding property is improved by PTFE, and the adhesion of aluminum oxide is almost completely prevented, so that stable conductivity can be maintained. Further, the hardness of PTFE-containing Ni-B plating is Hv600-800, and the hardness of PTFE-containing Ni-W plating is Hv550-600, which is harder than the hardness Hv250-300 of the conventional PTFE-containing Ni plating.
Since the hardness of E-containing Ni-P plating can be increased to Hv 450 to 550 by aging treatment, abrasion of various PTFE-containing plating layers due to scraped aluminum oxide can be further suppressed.

When the base material of the probe needle is, for example, tungsten, Ni or Cu plating, for example, is preferably applied as a base, whereby the adhesion of various PTFE-containing plating, which is the main plating, can be enhanced. The Ni or Cu plating in that case is particularly preferably electroplating, whereby the main plating and the base material can be completely adhered. Further, it is preferable that the underlying Ni or Cu plating has a thickness of 0.5 to 2 μm and the various PTFE-containing plating has a thickness of 0.5 to 5 μm. The Ni or Cu plating as a base has a thickness of at least 0.5 μ of the strike bath in order to secure the adhesion of various PTFE-containing plating.
It is necessary to be at least m, and the thickness exceeding 2 μm is wasteful in terms of cost and time. In addition, in the case of various PTFE-containing plating, a thickness of 0.5 μm or more is required to secure slipperiness and wear resistance, and even if thicker than 5 μm, N
Like i or Cu plating, it is wasteful in terms of cost and time.

[0014]

DETAILED DESCRIPTION OF THE INVENTION An example of an embodiment of the present invention will be described below with reference to the drawings.

1 and 2 show an example of an embodiment of the present invention, and FIG. 1 is a plan view showing an intermediate specification of a probe needle,
FIG. 2 is a plan view showing the final specifications of the probe needle.

In FIG. 1, the probe needle 1 has a base material of, for example, tungsten, a wire diameter a of 0.1 to 0.7 mm, and a total length b of 25 to 90 mm. Then, the tip side is sharpened into a linear taper shape over a predetermined length c (for example, 0.3 to 6 mm), and the end surface has a diameter d of 0.02 mm or less.

The probe needle 1 thus processed is shown in FIG.
In the straight state, first, by electroplating Ni
Plating is performed, and the needle tip portion is plated with PTFE-containing Ni-B using the Ni plating layer as a base. The plating as the base may be Cu plating in addition to Ni plating, and may be metal plating such as Zn plating.
Ni plating is the most preferable in terms of adhesion to the E-containing plating. The plating applied to the needle tip may be PTFE-containing Ni-W plating or PTFE-containing Ni-P plating. Further, PTFE-containing Ni-W plating is electroplating, PTFE-containing Ni-B plating, and PTFE-containing N
The i-P plating is preferably electroless plating, and the PTFE-containing Ni-P plating is subjected to heat treatment (aging treatment) at 250 to 350 ° C. for about 1 hour.

In FIG. 1, 2 is a Ni plating layer,
3 is PTFE-containing Ni-B plating. In the illustrated example, the entire surface of the base material is covered with the Ni plating layer 2, and the PTFE-containing Ni-B plating layer 3 is formed in the range extending from the pointed portion to a part of the needle barrel. The range of the PTFE-containing Ni-B plating layer 3 is not limited to the above-mentioned example,
It can be appropriately changed within a range including at least the end surface of the needle tip portion and not reaching the portion to be soldered to the printed wiring of the needle barrel portion. Also, in the illustrated example, the Ni plating is PTFE.
Although it is the base of the Ni-B plating containing, it is applied to the entire surface for the purpose of improving the solderability in the needle barrel, but the Ni plating does not necessarily have to be applied to the entire surface at the same time. Ni plating may be separately applied to the plating base portion and the soldering portion.

The Ni plating as the base has a thickness of 0.5 to 0.5 in order to secure the amount of the PTFE-containing Ni-B plating attached.
2 μm is preferable. The thickness exceeding 2 μm is wasted in terms of cost and time. In addition, PTFE-containing Ni-B
It is preferable that the plating has a thickness of 0.5 to 5 μm in order to secure slipperiness by PTFE. Also in this case, the thickness exceeding 5 μm is wasted in terms of cost and time.

After the PTFE-containing Ni-B plating is applied in this way, the probe needle 1 is used by bending the tip of the pointed portion into a hook shape as shown in FIG.

The probe needle 1 has a PTFE-containing N
By being covered with the i-B plating layer 3, the conductivity is good, the oxidation of the end face in contact with the integrated circuit is prevented, and the sliding property is improved by PTFE so that the aluminum oxide is almost completely adhered. It can be prevented and can maintain stable conductivity. Further, since the PTFE-containing Ni-B plating has a higher hardness than the conventional Ni plating, it is possible to further suppress the abrasion of the plating layer due to the scraped aluminum oxide, and to greatly improve the number of contacts as compared with the conventional one. Is possible.

As a result of actually conducting a current test with a probe card using the probe needle 1, the number of contacts of the conventional PTFE-containing Ni plating is 300,000 to 50 times.
It was confirmed that the conductivity did not decrease even with a contact that was about 1.5 times as many as 500,000 to 700,000 times with respect to 10,000 times.

The present invention can be applied to a probe needle having rhenium tungsten, beryllium copper or the like as a base material in addition to tungsten.

The present invention can also be applied to a probe needle whose tip is not sharpened.

[0025]

The probe needle of the present invention has a PTF tip.
E-containing Ni-B plating, PTFE-containing Ni-W plating,
Alternatively, since it is covered with the aging-treated PTFE-containing Ni-P plating, the electrical conductivity is good, and the oxidation of the end face in contact with the integrated circuit is prevented. Adhesion is almost completely prevented, and stable conductivity can be maintained. Furthermore, PT
The FE-containing Ni-B plating, the PTFE-containing Ni-W plating, and the aged PTFE-containing Ni-P plating all have higher hardness than the conventional Ni plating, so that the wear of the plating layer can be further suppressed. Therefore, the number of contacts can be significantly improved as compared with the conventional case. As a result, the number of maintenances and the time required therefor can be significantly reduced, so that the stock of spares can be reduced, and the inspection cost and thus the manufacturing cost can be significantly reduced.

[Brief description of drawings]

FIG. 1 is a plan view showing an intermediate specification of a probe needle according to an example of an embodiment of the present invention.

FIG. 2 is a plan view showing final specifications of the probe needle of FIG.

[Explanation of symbols]

1 probe needle 2 Ni plating 3 PTFE-containing Ni-B plating

Claims (2)

[Claims] 1. A probe, characterized in that at least the end face of the tip portion is covered with any one of PTFE-containing Ni-B plating, PTFE-containing Ni-W plating, and aged PTFE-containing Ni-P plating. Card probe needle. 2. PTFE-containing Ni-B plating, PTFE
The probe needle for a probe card according to claim 1, wherein Ni or Cu plating is applied to a base of the containing Ni-W plating or the PTFE-containing Ni-P plating.