JPH1151970A - Probe card - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the contact resistance, and to secure a good electrical contact in a probe needle which is electrically brought into contact with the pad of a semiconductor integrated circuit device for carrying out the measurement by means of a tester. SOLUTION: In a probe card provided with a probe needle 8 which is electrically brought into contact with the pad 1c that has been provided to a semiconductor integrated circuit device 1 for electrically connecting the semiconductor integrated circuit device with a tester; the end part 8b of the probe needle 8 is made up of a plurality of projected parts 9, each of which is made up in a lattice-shaped projection whose end has an acute triangular shape in section, or in a weight-shaped projection whose end has an acute triangular shape in section. Since a plurality of projections 9 are electrically brought into contact with the pad 1a respectively, the contact surfaces are increased, and the contact resistance can be reduced. Further, since a plurality of projections 9 break through the oxide film on the surface of time pad 1a respectively, a proper electrical contact can be enabled.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a probe card used for evaluating a semiconductor device in a wafer state, and more particularly to an improvement in the shape of the tip of a probe needle which contacts a bonding pad of a wafer.

[0002]

2. Description of the Related Art In general, an inspection apparatus called a tester is used to measure the electrical characteristics and the like of a semiconductor device formed on a semiconductor wafer in a process of manufacturing a semiconductor integrated circuit device (IC). In this tester, a probe card as a board for electrically connecting the IC pad (electrode) and the tester main body is provided, and a needle provided in the probe card, that is, a probe needle, is attached to the IC pad. To make electrical connection to the IC. This probe card is composed of the probe needles described above and a fixed board for fixing and supporting a plurality of probe needles.

FIGS. 4 (a) and 4 (b) show an enlarged view of the tip of a probe needle and a cross-sectional view of a contact state with a pad of an IC in a conventional probe card, respectively. In the conventional probe card, the tip 8b of the probe needle 8 is sharp and has a conical shape. The tip 8b of the probe needle 8 is brought into contact with the surface of the pad 1a formed of the conductive film 12 formed on the surface of the silicon substrate 11 of the IC 1 and covered with the protective film 13 and electrically connected through the pad 1a. Is performed. Examples of such a probe card include those described in JP-A-62-295426 and JP-A-4-199836.

However, in such a probe card, since the tip 8b of the probe needle 8 is sharp,
The contact area with the pad 1a is small, and the contact resistance tends to increase. For this reason, when a weak current flows, the current is reduced by the contact resistance, and there is a problem that suitable measurement becomes difficult. For this reason, conventionally,
As shown in FIG. 5 (a) or FIG. 6 (a), the tips of the probe needles 8 and 8A are formed flat, and the flat tip surface 8 is formed.
A configuration has been proposed in which c contacts the pad 1a. FIG. 5B or FIG.
As shown in (b), the contact area between the pad 1a and the probe needle 8 can be increased, and the above-described contact resistance can be reduced. Examples of such a probe card include, for example, JP-A-62-295426 and JP-A-4-19.
There is one described in JP-A-9836.

[0005]

However, in such a configuration in which the tip of the probe needle is formed flat, it is good when the probe needles 8 and 8A contact the surface of the pad 1a at a correct angle, but the angle is shifted to that angle. In such a case, the tip surface 8c of the probe needles 8 and 8A does not correctly contact the surface of the pad 1a, resulting in a line or point contact state, and the contact area increases and the contact resistance decreases. Each effect of reduction may not be obtained.
Generally, this type of probe needle breaks a thin oxide film of about 100 ° generated on the surface of the pad to make electrical connection, and for that purpose, the tip of the probe needle is configured to be sharpened. When the thin oxide film is formed in such a plane, the thin oxide film cannot be broken, and as a result, there arises a problem that a suitable electrical contact cannot be made.

SUMMARY OF THE INVENTION It is an object of the present invention to reduce the contact resistance between a probe needle and a pad, to enable a suitable electrical contact between the two, and to improve the accuracy of measurement and improve the reliability of a test. Another object of the present invention is to provide a probe card which has a high reliability.

[0007]

A probe card according to the present invention is characterized in that the tip of a probe needle electrically contacting an IC pad is constituted by a plurality of projections. Here, the protruding portion is configured as a lattice-shaped protruding portion having an acute-angled triangular cross-sectional shape or a weight-shaped protruding portion having an acute-angled triangular cross-sectional shape.
In addition, it is preferable that each of the protrusions has a sawtooth cross section.

[0008] Since each of the plurality of projections makes electrical contact with the pad, it is possible to increase the contact area and reduce the contact resistance. Further, since the plurality of protrusions respectively break through the oxide film on the pad surface, suitable electrical contact is possible.

[0009]

Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing a schematic configuration of a main part of a tester provided with a probe card of the present invention.
An IC to be tested, here a silicon wafer 1, is mounted on the stage 2, and is supported movably up and down by an up-down driving mechanism 3 provided below the stage 2. A fixed board 4 is horizontally disposed above the stage 2 and is supported by a test mechanism (not shown). A probe card 5 is supported on the fixed board 4. In the probe card 5, a rectangular window 6a is opened in the insulating substrate 6, and a required circuit pattern 7 is formed on the surface thereof, and is electrically connected to a test circuit (not shown). A large number of probe needles 8 are arranged in the rectangular window 6a. Each probe needle 8 has a base end 8a connected and fixed to the circuit pattern 7, and a distal end 8b connected to the rectangular window 6a. It protrudes downward through 6a. Therefore, by raising the stage 2, the tips 8 b of the probe needles 8 are brought into contact with the pads 1 a provided on the IC 1, and the probe needles 8 and the circuit patterns 7 are formed.
The IC 1 and the test circuit are electrically connected to each other through the interface so that a required test is executed.

FIG. 2A shows the tip 8 of the probe needle 8.
It is an enlarged perspective view of b. Tip 8b of this probe needle 8
Is formed in a conical overall shape.
c is formed on a surface that is inclined with respect to the axial direction of the probe needle, and a plurality of protrusions 9 whose acute ends are triangular in cross section are arrayed and formed on the distal end surface in a lattice shape. . Alternatively, as shown in FIG. 2 (b), a plurality of minute conical projections 9A having sharp acute ends may be regularly or irregularly arranged on the distal end surface 8c. Here, the tip surface 8c has a diameter of 80 μφ.
It is formed as the following circle or ellipse. Also,
The protrusion 9A in FIG. 2B may be a pyramid type.

FIG. 3 shows an example of the probe card 5 according to the present invention.
It is an expanded sectional view of an important section in the state where a test of C1 is performed. In the IC 1, a conductive film 12 having a required pattern formed on the surface of a substrate 11 of a silicon wafer is covered with a protective film 13, and is exposed to an opening provided in the protective film 13 so that the conductive film 12 A pad 1a is formed. Then, as shown in FIG. 1, the stage 2 is lifted, and the pad 1a is brought into contact with the tip of the probe needle 8, whereby the probe needle 8 as shown in FIG.
And the pad 1a is in electrical contact. At this time, since the protruding portions 9 having sharp tips are disposed on the distal end surface 8c of the probe needle 8, an oxide film (not shown) generated on the surface of the pad 1a at the distal ends of these protruding portions 9 is provided. And electrical contact is made with the conductive film 12 of the pad 1a. Therefore, the probe needle 8 and the pad 1a are electrically contacted with each other at the plurality of protrusions 9, so that the contact area is increased and the contact resistance is reduced as compared with the conventional configuration where the probe needle 8 and the pad 1a are contacted with one sharp tip. It is possible to do. On the other hand, since the tip of each of the plurality of projections 9 breaks through the oxide film on the pad surface, good electrical contact can be obtained.

In particular, in the probe needle 8 having the configuration shown in FIG. 2A, since the projections 9 are formed in a lattice shape, each projection 9 and the pad 1a are in line contact with each other. The contact resistance can be reduced as compared with the configuration of the protruding protrusion 9A in which each of the configurations in b) is independent. On the other hand, FIG.
In the configuration (b), since each projection 9A is sharp, the effect of breaking the oxide film at each projection 9A is high, and the electrical contact at each projection 9A is extremely effective.

The tip surface 8c of the probe needle 8 is
Formed as parallel as possible to the surface of the pad 1a,
The projections 9 and 9A have their respective center lines perpendicular to the distal end face 8c, that is, the probe needle 8 and the pad 1
It is preferable to be configured so as to protrude in the direction in which a contacts with a. As a result, the cross-sectional shape of each projection 9, 9A is
It is preferably formed in a sawtooth shape deviated to one side with respect to the front end face 8c. As a result, each of the protrusions 9 and 9A comes into contact with the surface of the pad 1a in the vertical direction, so that the oxide film is more effectively broken and a suitable electrical contact is made possible.

The above-described embodiment is an example of the present invention, and in particular, the shape of the projections provided on the distal end surface of the probe needle can be applied to various arrangements other than the arrangement described above. It is.

[0015]

As described above, according to the present invention, since the tip of the probe needle is constituted by a plurality of protrusions, each of the plurality of protrusions makes electrical contact with the pad.
It is possible to increase the contact area and reduce the contact resistance. Further, since the plurality of protrusions respectively break through the oxide film on the pad surface, suitable electrical contact is possible. In this case, as the shape of the projection, the tip is formed as a lattice-shaped projection having a triangular cross section with an acute angle, or the tip is formed as a weight-shaped projection with a triangular cross section with an acute angle. In addition, the oxide film can be more suitably broken, and a more favorable electrical contact state can be obtained. In particular, since the cross-sectional shape of the projection is saw-toothed, it is possible to effectively use the contact force applied to each projection when the probe needle contacts the pad, thereby making it possible to break the oxide film. Become.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a main part of a tester to which a probe card of the present invention is applied.

FIG. 2 is an enlarged perspective view of a distal end portion of the probe needle according to the present invention.

FIG. 3 is a sectional view showing a contact state between a probe needle and a pad in FIG. 2;

FIG. 4 is a perspective view of a tip portion of a probe needle of a conventional probe card and a cross-sectional view of a contact state thereof.

FIG. 5 is a perspective view of a tip portion of a probe needle in a conventional improved probe card and a cross-sectional view of a contact state thereof.

FIG. 6 is a perspective view of a tip portion of a probe needle in another conventional improved probe card and a sectional view of a contact state thereof.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 IC 2 Stage 3 Vertical drive mechanism 5 Probe card 6 Insulating board 7 Circuit pattern 8 Probe needle 8b Tip 8c Tip 9, 9, 9A projection

Claims (4)

[Claims] 1. A probe card having a probe needle electrically connected to a pad provided on a semiconductor integrated circuit device and electrically connecting the semiconductor integrated circuit device to a tester, wherein a tip of the probe needle is A probe card comprising a plurality of protrusions. 2. The probe card according to claim 1, wherein the projection is a lattice-shaped projection having a triangular cross section with an acute tip. 3. The probe card according to claim 1, wherein the projection is a weight-shaped projection having a triangular cross section with an acute tip. 4. The probe card according to claim 2, wherein the protrusion has a saw-tooth shape in cross section.