JPH09102521A - Probe card - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the electrical characteristics of a probe by bonding a conductive ground plane to a substrate closer to a probe edge part from a support for fixing the probe to the substrate to the tip of the probe in contact with the bonding pad of a semiconductor element. SOLUTION: A ground plane 7 is newly provided closer to a probe edge part from a support 5 of a probe 4 to the tip of the probe 4 in contact with a bonding pad 11 of a semiconductor element to control impedance. Then, the size and proximity distance of the ground plane 7 are preset so that a specific capacity can be obtained considering, for example, the diameter and length of the probe 4 for adjusting impedance, thus improving the electrical characteristics of the probe without any drastic change in a probe card.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a probe card which is a jig for measuring the electrical characteristics of semiconductor elements such as integrated circuits.

[0002]

2. Description of the Related Art The electrical characteristics of an integrated circuit or the like are first measured in a wafer state. This electrical characteristic is obtained by touching a probe fixed on a probe card to a bonding pad that is an external terminal of the integrated circuit, and inputting an electrical signal from an electrical characteristic testing device such as a tester through this probe and an output waveform from the integrated circuit. Is transmitted to the electrical characteristic test equipment of.

A conventional example of a probe card is shown in FIG. In FIG. 3, 1 is a substrate of a probe card, 1a is a printing pattern on the surface of the substrate, 1b is an inner layer pattern of the substrate, 2 is a pad for connecting an electric characteristic test device, 3 is an opening of the substrate, 4 is a probe, 5 is A support for fixing the probe, 6 is a fixing layer for fixing the probe 4 to the support 5. The probe 4 does not have a coaxial structure but is a needle made of tungsten and having a length of 2 to 3 cm. The tip of the probe 4 comes into contact with the bonding pad of the semiconductor element formed on the wafer to be measured, and the electrical characteristic test is performed. Therefore, even if a strip line having a characteristic impedance of 50Ω or the like is used on the substrate 1, in the measurement at a high frequency of several tens MHz or more due to the mismatch of the impedance of the needle portion, that is, the probe 4, and the influence of its inductance component. There is a problem that it cannot be used.

[0004]

As described above, the conventional probe has a big problem that it cannot be used for measurement at a high frequency of several tens of MHz or more due to impedance mismatch and the influence of the probe inductance. .

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above problems and to provide at low cost a means for improving the electrical characteristics of a probe without making a drastic change in the conventional probe card.

[0006]

The probe card according to the present invention is electrically conductive to the substrate in proximity to the probe end portion from the support for fixing the probe to the substrate to the tip of the probe in contact with the bonding pad of the semiconductor element. It is a fixed ground plane.

[0007]

In the present invention, since the ground plane is provided in the vicinity of the probe end portion and the impedance is adjusted, impedance mismatching and deterioration of electrical characteristics due to inductance are eliminated.

[0008]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a first embodiment of the present invention.
The state at the time of non-measurement is shown in (a), and the state at the time of measurement is shown in (b). 1A and 1B, for simplification of description, a right half sectional view of the probe card is shown, and elements given the same reference numerals as those in FIG. 3 show the same portions. 7 is made of a conductive metal such as copper and is a ground plane connected to the ground of the substrate 1 as described later. The ground plane 7 is fixed to the substrate 1 at a position where the distance from the probe 4 becomes a desired impedance and is further connected to the ground of the substrate 1. Therefore, in the present embodiment, the substrate 1 is
It is soldered to the prepared ground 8 around the rear surface (lower surface) of the opening 3. In addition, 10 is a wafer to be measured, 11
Indicates a bonding pad.

As can be seen from the structure of FIG. 1, the present invention provides a new ground plane 7 by bringing it closer to the probe end portion from the support 5 of the probe 4 to the tip of the probe 4 which contacts the bonding pad 11 of the semiconductor element. Is provided to control the impedance of the probe 4. Only by adding the ground plane 7 in close proximity to the probe 4, this can be achieved without making a great change to the structure of the conventional probe card. In adjusting the impedance, the size and proximity distance of the ground plane 7 are determined in advance so that the required capacitance can be obtained in consideration of the diameter and length of the probe 4.

FIG. 2 shows a second embodiment of the present invention, and like the first embodiment of FIG. 1, only the right half of the probe card is shown. This embodiment is characterized in that the connection to the ground 8 of the substrate 1 of the probe card shown in FIG. 1 is the ground 8 prepared on the surface (upper surface) of the substrate 1 of the probe card. In the present embodiment, this ground plane 7 is fixed to the substrate 1 of the probe card and is further soldered to the ground 8 prepared on the surface of the substrate 1. The ground plane 7 may be fixed not by soldering but by screwing. With this structure, the ground plane 7 for impedance control can be attached after the conventional probe card is produced.

Although the present invention has been specifically described above based on the embodiments, it is needless to say that the present invention is not limited to the embodiments and various modifications can be made without departing from the scope of the invention. . For example, the electrical connection between the ground plane 7 and the ground 8 of the probe card can be performed by various methods such as a method using a conductive adhesive other than the method using solder.

[0013]

As described above, according to the present invention, a conductive ground is provided on the substrate by approaching the probe end portion from the support for fixing the probe to the substrate to the tip of the probe contacting the bonding pad of the semiconductor element. Since the plane is fixed, the impedance of the probe can be controlled and the electrical characteristics of the probe can be improved. Further, it can be achieved at a low cost without making a great change to the structure of the conventional probe card.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of a main part of a probe card showing a first embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view of a main part showing a second embodiment of the present invention.

FIG. 3 is a schematic sectional view showing an example of a conventional probe card.

[Explanation of symbols]

 1 Probe Card Substrate 1a Substrate Surface Printing Pattern 1b Substrate Inner Layer Pattern 2 Electrical Property Test Equipment Pad 3 Substrate Opening 4 Probe 5 Support for Fixing Probe 6 Fixing Layer 7 Ground Plane 8 Ground 10 Cover Measurement wafer 11 Bonding pad

Claims (1)

[Claims] 1. A probe card used for an electrical characteristic test of a semiconductor element by contacting the probe with a bonding pad of a semiconductor element formed on a wafer to be measured, from a support body which fixes the probe to a substrate. A probe card in which a conductive ground plane is fixed to the substrate in the vicinity of a probe end portion up to the tip of the probe that contacts the bonding pad of the element.