JP2770785B2 - Probe card - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a probe card, and more particularly, to a probe card used for testing the electrical performance of a semiconductor integrated circuit in a wafer state.

[0002]

2. Description of the Related Art Probe cards are used for inspecting the electrical performance of semiconductor devices in a wafer state. FIG.
FIG. 2 is a cross-sectional view showing the structure of a conventional probe card.
The probe card includes a substrate 11 having a built-in pattern wiring for transmitting a signal from a measuring device, and a number of probe needles 12 supported by the substrate 11. By contacting the surface (pad surface), an electric signal for a test is bidirectionally transmitted between the measuring device and the semiconductor device in the wafer.

[0003]

In the above conventional probe card, when the probe needle 12 comes into contact with the pad surface, the fulcrum of the probe needle 12 is obliquely above the contact position. For this reason, the probe needle 12 may be laterally displaced on the pad surface due to the contact pressure with the pad surface, and the pad surface may be damaged due to the sharp needle shape, resulting in poor electrical contact between the probe needle and the pad surface. There were drawbacks that occurred.

In order to eliminate the above-mentioned disadvantages, Japanese Patent Laid-Open Publication No. 2-388
No. 64, a small metal rod extending parallel to the pad surface,
There has been proposed a probe card having a structure including a pad needle supported by the small metal rod via an elastic material and capable of extending and contracting in a direction perpendicular to the pad surface. However, this structure has a high manufacturing cost due to a complicated structure such as the use of a leaf spring.

In Japanese Patent Application Laid-Open No. 3-51769,
A structure has been proposed in which a spring portion continuous to a tip portion extending in a direction perpendicular to the pad surface is housed in a housing. In this structure, it is possible to make a single-row contact at a narrow pitch, but it is not suitable for, for example, simultaneously contacting each probe needle with pad surfaces respectively arranged on four sides of a wafer chip. In addition, the structure is complicated and expensive.

In view of the above, it is an object of the present invention to provide a stable electrical connection between the probe needle and the pad without damaging the pad surface because the tip of the probe needle does not shift laterally even when contact pressure is applied from the pad surface. An object of the present invention is to provide a highly reliable and low-cost probe card since contact can be obtained.

[0007]

According to the present invention, there is provided a probe card comprising: a metal probe needle contacting a pad of a semiconductor integrated circuit; and a substrate supporting the probe needle, wherein the probe needle comprises: A plurality of bases respectively supported by the substrate, a rigid acute-angled tip that forms an acute angle on the opposite side to the pad and contacts the surface of the pad, and is disposed between the base and the tip. And a spring portion.

[0008] In the probe card of the present invention, the material constituting the probe needle only needs to have conductivity and elasticity, and there is no particular limitation on the material. Further, any material conventionally used for this type of probe card can be used for the substrate.

As used herein, the term “the tip of the probe needle is combined into one” includes the case where the entirety of the probe needle is formed of an integral member, and further includes a plurality of members. May be joined by a brazing material or the like at the tip.

[0010] The probe needle of the probe card of the present invention comprises:
Preferably, it is formed rotationally symmetric with respect to a central axis perpendicular to the pad surface. In this case, the deformation in the direction perpendicular to the pad surface is ensured by the contact pressure received from the pad surface.

[0011]

[0012]

In the probe card according to the present invention, the contact portion is formed by adopting a configuration in which the central spring portions extending from the plurality of base portions of the probe needle supported by the substrate are joined together at the tip of the probe needle. When the contacting tip receives contact pressure from the pad surface, it expands and contracts in a direction perpendicular to the pad surface by the action of the plurality of central springs and the base, so that the probe needle moves in a direction parallel to the pad surface. Since the pad surface is not easily damaged, stable electrical contact with the pad surface can be obtained.

[0013]

Hereinafter, the present invention will be described in more detail based on examples of the present invention. FIG. 1 is a sectional view showing a structure of a probe card according to a first embodiment of the present invention together with a pad surface of a wafer. The probe card has a substrate 11 which incorporates pattern wiring connected to a measuring device and is disposed so as to be movable in a direction perpendicular to the wafer, and a probe needle 12 supported by the substrate 11. The probe needles 12 are supported by the substrate 11 at two points, and come into contact with the surfaces of the pads 22 formed on the wafer 21 at a predetermined contact pressure. This allows
The probe card electrically connects a measurement device (not shown) and an electric circuit of the wafer.

The probe needle 12 is formed entirely of, for example, a thin metal wire, and has two bases 1 supported on the substrate 11 respectively.
2A and a spring-shaped 2A extending from the base 12A.
It is composed of two central spring portions 12B and a tip portion 12C where the two spring portions are combined into one. Probe needle 1
Numeral 2 is formed rotationally symmetrical with respect to an axis in a direction perpendicular to the pad surface, and in this embodiment, is composed of two thin metal wires lying in the same plane. The probe needle can be composed of two or more thin wires of an arbitrary number, or
It is also possible to use a thin metal wire and support both ends of the thin metal wire on the substrate 11.

In this embodiment, the tip 1 of the probe needle 12 is
In 2C, the opposite side to the pad surface forms an acute angle and is in contact with the pad surface. Since the probe needle 12 is supported by the substrate 11 at two places, when it receives a contact pressure from the pad surface,
The elasticity of the central spring portion 12B expands and contracts in a direction perpendicular to the pad surface. Therefore, unlike conventional probe cards,
There is no damage to the pad surface due to lateral displacement.

The fine metal wires constituting the probe needle include:
For example, tungsten having a diameter of 40 μm and a tip portion of 30 μm can be used.

[0017]

The configuration of the above-described embodiment is merely an example, and the probe card of the present invention is not limited to the configuration of the above-described embodiment, but can be variously modified and changed from the configuration of the above-described embodiment. Are also included in the scope of the present invention.

[0019]

As described above, in the probe card of the present invention, the probe needle expands and contracts in the direction perpendicular to the pad surface by the contact pressure from the pad surface acting on the probe needle. Since there is no displacement and no damage to the pad surface, stable electrical contact can be obtained and a highly reliable performance test of the wafer can be performed.

[Brief description of the drawings]

FIG. 1 is a sectional view of a probe card according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of a conventional probe card.

Claims (2)

(57) [Claims] 1. A probe card comprising a metal probe needle contacting a pad of a semiconductor integrated circuit and a substrate supporting the probe needle, wherein the probe needle has a plurality of bases respectively supported on the substrate, A probe card, comprising: a tip portion that forms an acute angle on the side opposite to the pad and contacts a surface of the pad; and a spring portion disposed between the base portion and the tip portion. 2. The probe card according to claim 1, wherein the probe needle is rotationally symmetric about an axis perpendicular to the pad surface.