JPS6080772A - Probe needle - Google Patents

Abstract

PURPOSE:To improve accuracy of measurement by forming the base of the tip of a probe needle body to be used by being mounted to a probe card in the stage of testing the characteristics of an integrated circuit into the shape having a curved surface like a partially circular cylindrical circumferential surface so that the tip contacts stably and linearly with the terminal surface of an object to be tested. CONSTITUTION:A probe needle body 11 consists of a fine wire of a circular section consisting of tungsten, palladium alloy, beryllium copper or the like. The tip 12 thereof is converged and the front and rear surfaces 14 thereof are formed of the surfaces each truncated to a tapered flat shape. The base 13 is formed to a curved surface consisting of a partially circular cylindrical circumferential surface. The tip 12 is positioned and set on the terminal 15 of an integrated circuit 10 at a specified angle. The base 13 contacts linearly with the surface of the terminal 15 thereby applying stably prescribed contact pressure onto the terminal 15.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a probe needle that is attached to a probe card and used when testing the characteristics of integrated circuits such as wafers.

Generally, a probe card is configured as follows. That is, as shown in FIGS. 1 and 2, the probe card 1 includes a substrate 2, a globe ring 3, and a number of probe handles attached to the lower surface of the globe ring 3. As shown in FIGS. The substrate 2 has a built-in circuit (hereinafter referred to as a peripheral circuit) for testing the electrical characteristics of the integrated circuit or for assisting the test, and has a ring-shaped fixing part 5 into which a globe ring 3 is fitted and fixed. At the same time, a tester 6 is attached to the proximal end.
It has a connector 7 to be connected to. A socket portion 8 is formed in the fixing portion 5 and is electrically connected to a peripheral circuit. On the other hand, the same number of pin portions 9 as the glove needles 4 are formed on the upper surface of the globe ring 3, and the pin portions 9 are electrically connected to the probe needles 4. Then, at the same time as mechanically fitting the glove ring 3 to the fixed part 5,
The pin part 9 is fitted into the socket part 8, and thereby the board 2
The upper peripheral circuit and the probe needle 4 (!:) are electrically connected.Then, the tester 6 is connected to the connector 7 of the board 2, and the globe needle 4 is connected to each terminal of the integrated circuit under test 10. The characteristics of the integrated circuit 10 are tested by contacting the integrated circuit 10 with ξ.

Incidentally, the probe needle 4 is required to ensure that its main body 110 and needle tip 12 contact the terminals of the integrated circuit 10 to be tested. However, as shown in FIGS. 7(A) and 7(B), in the conventional globe needle 4, the bottom surface 13 of the needle tip 12 that contacts the terminal is partially spherical (FIG. 7(A)).
Or, since it was formed in a circular planar shape (Fig. 7 (b)), in either case, it makes point contact with the terminal surface, and therefore, when the contact pressure is weak, In any case, it is impossible to completely avoid unstable contact conditions, which can lead to poor contact, and when the contact pressure is strong, it can cause damage such as pinholes on the terminal surface of the contact area, and sufficient measurement accuracy is required. There was a problem that it was difficult to obtain.

The present invention was made to solve this problem, and by fundamentally improving the bottom shape of the tip of the globe needle body, the bottom surface can be brought into stable line contact with the terminal surface, thereby improving measurement accuracy. The purpose is to achieve this goal.

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 3 shows the main parts of the probe needle according to the present invention,
The probe needle body 11 is made of a material such as tungsten, palladium alloy, or beryllium, and has a shape in which the tip of a thin wire with a circular cross section is bent downward at an obtuse angle. This main body 11 has its proximal end attached to the lower surface of the globe ring 4 and is electrically connected to the peripheral circuit on the substrate 2 of the glove card 1, as in the well-known configuration described above (first (See Figure and Figure 2).

In FIG. 4, the needle tip part 1 of the glove loaf-dol body 11
2 is formed in a tapered shape, and its front and rear surfaces 14 and 14 are formed into inclined planar mounting surfaces.

Now, the bottom surface 13 of this needle tip portion 12 is formed into a curved surface consisting of a partially cylindrical peripheral surface, and the diameter of the curved surface is set to an extent not exceeding approximately 0.51 m.

In such a case, as shown in FIGS. 5 and 6, the needle tip 12 is positioned on the terminal 15 of the integrated circuit 10 at a certain angle, and its bottom surface 13 contacts the surface of the terminal 15. During contact, the curved bottom surface 13 comes into line contact with the surface of the terminal 15, as is clear from both figures above, and a predetermined contact pressure is stably applied onto the terminal 15.

Note that the bottom surface 13 of the needle tip 12 may be affected by variations in the contact angle between the needle tip 12 and the terminal 15 or
When taking into account displacement movement on the surface, it is desirable to form a curved surface made of the peripheral surface of a perfect cylinder in order to maintain stable contact pressure. It is also possible to form a curved surface within the range of a partially cylindrical circumferential surface. Further, the cross-sectional shape of the globe needle main body 11 may be circular or rectangular.

As explained above, according to the present invention, the bottom surface of the tip of the probe needle body is made into a curved surface having a partial cylindrical peripheral surface shape, so that the curved bottom surface of the needle tip can be applied to a test object such as a wafer. It was assumed that the wire was in contact with the minute terminals of the integrated circuit. Therefore, since the contact pressure between the globe needle and the terminal is uniformly applied to the surface of the terminal, the contact pressure can be stabilized regardless of the strength of the contact pressure. Therefore, if an oxide film or the like is naturally formed on the terminal surface, the oxide film can be easily removed by applying strong contact pressure and sliding the bottom of the needle tip over the terminal surface. The cleaning effect stabilizes the contact resistance between the glove needle and the terminal at an appropriate value, contributing to improved measurement accuracy, and eliminates the risk of pinholes or other damage to the terminal itself. This makes it possible to reduce the incidence of defective products as much as possible during characteristic tests of the device under test, thereby improving the yield of the device under test. The effect is applied to the measurement of characteristics of dogs.

[Brief explanation of drawings]

1 and 2 show a well-known probe card, in which the first
The figure is a plan view, and FIG. 2 is a sectional view taken along the line II in FIG. 1. 3 to 6 show embodiments of the present invention, respectively. FIG. 3 is a side view of the main part, FIG. 4 is an enlarged perspective view of the needle tip, and FIG. 5 is an enlarged perspective view of the needle tip.
The figure is an enlarged front view of the main part showing the state of use, and FIG. 6 is a view taken along the V1 arrow in FIG. 5. FIGS. 7(a) and 7(b) are perspective views of needle tips showing different conventional examples. 1. Probe card, i.. Probe needle, 10
...Integrated circuit, 11 Probe needle body, 12...
Tip of the probe needle body, 13...bottom of the needle tip, 15...terminal of the integrated circuit. Applicant: ROHM Co., Ltd. Agent: Patent Attorney Kazuhide Okada Figure 1-'' Figure 2

Claims (1)

[Claims] (1) In a probe needle that is installed in a probe card used for characteristic testing of integrated circuits, and is configured so that the bottom surface of the needle tip of the probe needle body comes into contact with the terminal of the integrated circuit during use, the probe A probe needle characterized in that the bottom surface of the needle tip portion of the needle body is formed into a curved surface having a partially cylindrical peripheral surface shape.