JPH1038918A - Probe pin and contactor provided with it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To maintain the positional accuracy of the tip of a probe pin and to enhance the durability of the probe pin by a method wherein only the tip of the probe pin, for semiconductor measurement, which is composed of a needlelike single crystal and in which a conductive film is formed on the surface is covered with a material for a contact. SOLUTION: An electrode line 7 is formed on an SOI wafer 8 by an etching method, and an Au bump is then formed in a prescribed position on the electrode line 7. An Si needlelike single crystal is formed in the position by a VLS method, and the tip part of the needlelike single crystal is then polished so as to be uniform in a prescribed length. Then, a substrate film 4 is formed, in a prescribed thickness, on the surface of the needlelike single crystal 1 and on that of the electrode line 7 by an electroless plating operation, and an Au film 5 as a conductive film is then formed in a prescribed thickness by an electroplating method.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a probe card for measuring electrical characteristics of a semiconductor integrated circuit or the like, and more particularly, to a probe card which constitutes a probe card and which is an important part of a probe which is in contact with an electrode of the semiconductor circuit or the like, and the probe. It relates to a contactor whose pins are circuit-connected.

[0002]

2. Description of the Related Art In a manufacturing process of a semiconductor integrated circuit or the like,
Generally, when a large number of chips are formed on a semiconductor wafer, the electrical characteristics of each chip are measured, and the quality of the operation characteristics is determined. For this measurement, a contactor in which a number of probe pins are implanted according to the electrode shape of the device under test is used for a probe card.

In general, a probe card has a flatness of a virtual surface formed by a plurality of probe pin tips, a flatness of an electrode of an object to be inspected, and an evaluation in order to bring a plurality of probe pins into contact with electrodes. An error such as parallelism between the two when incorporated in a device is absorbed and a load necessary for stabilizing the contact resistance value is applied. For this reason, the probe pins are designed so that the space between the tip portion that comes into contact with the device under test and the portion where the probe card is fixed to the substrate portion is elastically bent. The amount of bending of the probe pin is called overdrive.

On the other hand, with the recent miniaturization and high integration of semiconductors, the pitch of probe pins has been narrowed. In this case, despite the necessity of increasing the accuracy of the probe pin tip position, the diameter of the probe pin is reduced, and when the necessary overdrive is applied for tens of thousands to hundreds of thousands of times, the plastic deformation of the probe pin may occur. This causes a problem that the positional accuracy of the tip of the probe pin is deteriorated. Furthermore, in recent wafer tests, high-temperature measurement for testing a wafer in a state where the wafer is heated to about 100 ° C. is becoming widespread, and deterioration of positional accuracy due to creep deformation of probe pins or the like has become a problem.

At present, most of the probe pins used are manufactured by implanting individual wires made of W into a printed wiring board. It is becoming difficult to meet the demands in both aspects of the manufacturing method and probe pin tip position accuracy.

Therefore, a method has been proposed in which a needle-like single crystal formed by VLS growth is applied (JP-A-5-19863).
No. 6, JP-A-5-215774, JP-A-5-215774
218156), these methods facilitate the production of a narrow pitch, high density probe card,
Moreover, the probe pins can be arranged with high accuracy.

The probe pin obtained by the above method is coated with a conductive film to make the needle-shaped single crystal conductive. However, the durability of the contact portion with the electrode cannot be maintained with the conductive film alone. A structure in which a contact material is further coated on the entire surface is adopted. Therefore, there is no problem in the accuracy of the probe pin tip position in the initial stage of use as a probe card, but after tens of thousands to hundreds of thousands of contacts, a permanent deformation of the coated film occurs, and the position accuracy of the probe pin tip deteriorates. There was a problem of doing.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and can cope with recent narrow pitches and high densities. A probe pin that can maintain the position accuracy of the tip of the probe pin even if the drive is loaded several hundred thousand times or more.
It is another object of the present invention to provide a contactor and a probe card having long-term durability.

[0009]

The present invention provides a probe pin for semiconductor measurement which is made of a needle-like single crystal and has a conductive film provided on the surface thereof, wherein only the tip is covered with a contact material. Preferably, the contact pin is a contact pin having the probe pin, wherein the contact material is coated by plating.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. As illustrated in FIG. 1, the probe pin of the present invention has a structure in which a conductive film 2 is provided on the surface of a needle-like single crystal 1, and a contact material 3 is further coated on the tip.

The needle-like single crystal of the present invention can be made of a material formed by VLS growth, for example.
Specifically, Si, LaB ₆ , Ge, α-Al ₂ O ₃ , G
aAs, GaP, MgO, NiO, SiC, InGa and the like. Among them, Si made of the same material as the semiconductor is preferable because it has the same characteristics such as the coefficient of thermal expansion and the positional accuracy of the probe pin does not easily change even at a high temperature. In general, the thickness of the acicular single crystal is several to 100 μm, and the length is several hundred μm to several mm.

The acicular single crystal 1 is generally provided with a conductive film 2 on the surface for the purpose of making it conductive.
A low electric resistance metal such as u or Cu can be formed by various known methods such as a plating method, a vapor deposition method, and a sputtering method. In this case, in order to suppress the plastic deformation of the conductive film due to overdrive as small as possible, it is preferable to form Au as a ductile material by a plating method, and the thickness thereof is preferably 1.0 to 3.0 μm.

The tip of the probe pin in the present invention means a portion where the deflection of the probe pin is small when overdrive is applied. Generally, when the total length of the probe pin is 1600 μm, it is about 300 μm from the tip. It is. The length of the tip portion of the probe pin covered with the contact material 3 is preferably about 20 to 200 μm from the forefront. If the length is short, the film of the contact material may sometimes peel off at the foremost portion. If the length is too long, the contact material 3 is plastically deformed due to overdrive, and the positional accuracy of the probe pin is deteriorated. Sometimes. The thickness of the contact material 3 varies depending on the load received by the probe pin. For example, when the contact load is 0.1 to 1.0 gf, the thickness is preferably 0.2 μm or more. There is no particular reason to set the upper limit of the thickness.
A thickness of about μm is sufficient. In the present invention, the shape of the tip portion of the probe pin is not limited, and for example, a conical shape or a shape with a rounded tip is also possible.

[0014] The contact material used in the present invention is a metal having low welding and contact movement, good corrosion resistance, and excellent durability with little wear even under several hundred thousand contacts under actual use conditions. Metals such as Pd, Ir, Rh, and Ni, Pd alloys obtained by adding metals such as Ag, Cu, Pt, and Au to Pd, and Ag alloys obtained by adding oxides such as Sn, In, Zn, and Cu to Ag are given. No. Of these, Pd
Is preferably used because it can be easily plated as described below, can be easily coated on the surface of a needle-shaped single crystal, and has excellent durability.

As a method of forming the contact material 3 only at the tip of the needle-like single crystal 1, for example, a portion where the contact material is not formed is masked with a resist or the like, and a plating method, a vapor deposition method, a sputtering method or the like is used. It can be easily formed by coating using a film forming method and removing the masking material later. However, a method of plating directly on only the front end portion without using the masking material is easier and more preferable. As another method of coating the needle-like single crystal with the contact material, a method of coating the entire needle-like single crystal by the above-described film forming method and then etching away an unnecessary portion except a tip portion is also possible.

[0016]

[Examples 1 to 7, Comparative Examples 1 to 3]

<Preparation of Intermediate> As illustrated in FIG. 2, an electrode line 7 is formed on an SOI wafer 8 by an etching method, an Au bump is formed at a predetermined position on the electrode line 7, and a Si bump is formed at that position. Is formed by the VLS method, and the tip of the needle-shaped single crystal is further polished to a predetermined length. Next, the needle single crystal 1 and the electrode line 7
A Ni underlayer 4 was formed to a thickness of 0.1 μm on the surface of the substrate by electroless plating, and an Au film 5 as a conductive film was formed to a thickness of 1.0 to 3.0 μm by electroplating. At this time, the target probe pin arrangement pattern is
This is a shape in which 300 pieces are arranged at a pitch of μm. In the above operation, by adjusting the size of the Au bump, the size at the time of polishing, and the thickness of the Au film, the diameter of the acicular single crystal is adjusted to 15 to 18 mm.
μm, the length is 1000 to 2000 μm, and the Au film thickness is 1.
A contactor intermediate having a probe pin of 0 to 3.0 μm was prepared and used as a sample for the subsequent operations.

<Embodiments 1 to 7> A suitable selection is made from the above samples, and about 100 μm from the tip of the probe pin is inserted into a brush dipped with a commercially available electrolytic Pd plating solution for brush plating, and the tip of the probe pin is inserted. Pd was plated. A platinum electrode was inserted into one side of the brush, and a current was applied between the brush and the electrode line 7 formed on the SOI wafer 8 to perform plating. At this time, the current density was 500 mA / mm ² , the plating solution temperature was 23 ° C., and the Pd film 6 having a thickness of 0.6 μm was formed by plating for 1 minute.
Could be formed.

With respect to the contactor obtained by the above operation, a probing durability test described later was performed, and the positional deviation of the tip of the probe pin before and after the contacting was measured. Table 1 shows the results. In the probing durability test, the overdrive was loaded at 40 μm, and the cycle time was 175 msec.
c, 1 million operations were performed under the condition of a contact time of 125 msec. The measurement of the position of the tip of the probe pin
Using a factory microscope with a Y stage (measurement accuracy ± 1 μm), the position coordinates of the tip of the probe pin before and after the durability test were measured at a magnification of 200 ×, and the value was obtained.

[0019]

[Table 1] * 1 Plating position on probe pin

<Comparative Examples 1 to 3> The samples were immersed together with the SOI wafer in a commercially available electrolytic Pd plating solution (solution temperature: 60 ° C.) in the same manner as in the examples, and the current density was 2 mA.
/ Dm2 for 40-200 seconds, 0.2-1.0
A Pd film 3 having a thickness of μm was formed on the entire surface of the probe pin and on the electrode line portion (see FIG. 3). The same evaluation as in Examples 1 to 6 was performed on the contactors obtained by this operation. The results are shown in Table 1.

[0021]

As is clear from the embodiments, the probe pin and the contactor of the present invention can maintain the position accuracy of the probe pin even when overdriven 1,000,000 times and have a long service life. Therefore, it is possible to cope with recent narrower pitch and higher density of semiconductor circuits, which is useful.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an example of a probe pin of the present invention.

FIG. 2 is a sectional view showing a probe pin according to the embodiment of the present invention.

FIG. 3 is a cross-sectional view showing a known probe pin according to a comparative example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Needle-like single crystal 2 Conductive film 3 Contact material 4 Ni base film 5 Au film 6 Pd film 7 Electrode line 8 SOI wafer 9 Contactor

Claims (3)

[Claims] 1. A probe pin for semiconductor measurement which is made of a needle-like single crystal and has a conductive film provided on the surface thereof, wherein only a tip portion is covered with a contact material. 2. The probe pin according to claim 1, wherein said contact material is plated. 3. A contactor having the probe pin according to claim 1.