JP2011022051A - Probe pin and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a probe pin capable of continuing stable measurement even when making repeated contact, by having sufficient rigidity and elasticity regardless of the kind of a material, and to provide a method for manufacturing the probe pin. <P>SOLUTION: This probe pin having a bending part on the tip side, whose forefront part makes contact with a measuring object, has a shell part to be fixed to a device on which the probe pin is to be mounted, and a flat part wherein a cross section from the tip side of the shell part to the bending part, to put it concretely, to the front of the bending part, or to a position including the bending part, or to the bending part and the tip part has a long shape to a bending direction of the tip part. More preferably, the sectional shape of the flat part forms a track shape. The flat part can be formed by rolling. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

The present invention relates to a probe pin for a probe card (hereinafter simply referred to as “probe pin”) that is used when conducting an energization inspection of an integrated circuit chip disposed on a semiconductor wafer.

Generally, a probe card is provided with several tens to several hundreds of probe pins on a printed wiring board. The probe card is mounted on a prober (inspection machine), and a probe pin is brought into contact with each electrode contact of the integrated circuit chip on the semiconductor wafer to conduct an energization inspection.

As the shape of the probe pin, one having a shape as disclosed in Patent Document 1 has been widely used. FIG. 5 shows a side view of a conventional general probe pin. The tip of the wire (pin) having a circular cross section is tapered. Next, the bent portion 110 is formed by bending. The base end portion 106 side of the body portion 104 is attached and fixed to a main body of a measuring instrument such as a probe card by solder welding or the like.

There are several points required for the probe pin configuration. One is desired to be made of a material having a high hardness so that deformation caused by wear is minimized as much as possible in inspections repeated several million times. It is desirable that the other has elasticity that can maintain stable contact with the electrode pad.

The above requirement can be solved by using, for example, tungsten having a high hardness as disclosed in Patent Document 2 as a material. Further, in order to obtain elasticity, in the shape as shown in FIG. 5, it is possible to easily obtain the bending by taking the body portion 104 long, and as a result, it is possible to provide elasticity.

For example, there is Patent Document 3 as a better form. FIG. 6 shows a typical example of Patent Document 3. The cross section from the body portion 104 to the tip portion 112 is a square or a rectangle, and the tip portion is a wedge shape. Since such a shape has high wear resistance and high elasticity, the width of the probe pin can be further reduced.

On the other hand, there are some points required as material characteristics for probe pins. One is used for inspection of electrical characteristics, and therefore needs to have a low specific resistance and good conductivity. The other is that oxidation resistance is required because an oxide film formed when the probe pin itself is oxidized may contaminate the inspection object.

In response to the above requirement, there is a probe pin using a material as disclosed in Patent Document 4, for example. If the material of Patent Document 4, specifically Au, Ag, Pd, Cu, or an alloy made of these metals is used, the specific resistance is low, the conductivity is excellent, and the noble metal is the main component. In addition, it is possible to obtain a probe pin that does not contaminate the inspection object.

JP 2002-071714 A JP-A-10-221366 JP 2001-116765 A JP 2008-304266 A

However, the conventional shapes or materials have the following problems.

For example, in order to obtain a shape as described in Patent Document 3, according to the described method, a heavy metal such as gold is used to create a mask for X-ray irradiation that takes the required probe pin shape, Resin for X-ray lithography is applied on the entire surface of the Si plate to form a resist. Next, the resist is irradiated with X-rays through a mask, and the resist irradiated with the X-rays is dissolved and removed with a developer to complete the mold. Thereafter, a metal serving as a material for the probe pin, for example, a Ni—W alloy, is electroplated to a required thickness on the dissolved and removed portion, and the Ni—W portion is released from the mold to obtain a probe pin base material. Further, the tip of the probe pin base material is subjected to necessary processing such as sharpening or tip bending by precision polishing, for example, to produce a probe pin.

In this way, a great deal of time is required to manufacture the mold. Further, the tip of each probe pin needs to be conical and the arrangement pitch of the probe pins needs to be narrow so that it can easily come into contact with dense electrode contacts. However, the probe pin disclosed in Patent Document 3 has a square or rectangular cross section of the completed base material, which makes subsequent peak processing difficult. In particular, it becomes extremely difficult to process the tip portion into a conical shape (taper processing).

In addition, when a material as described in Patent Document 4 is selected and a shape such as that shown in FIG. 5 is formed, noble metals such as Au and Ag are extremely soft and difficult to obtain rigidity. Therefore, deformation occurs during repeated contact with the electrode pad, or sufficient needle pressure cannot be obtained, and accurate measurement cannot be performed stably.

Therefore, an object of the present invention is to provide a probe pin that has sufficient rigidity and elasticity, regardless of the type of material, so that stable measurement can be continued even after repeated contact.

The probe pin of the present invention is
In the probe pin that has a bent part on the tip side and the most advanced part contacts the object to be measured,
A body portion for fixing to a device to which the probe pin is attached, and a flat portion whose cross section from the distal end side of the body portion to the bent portion is long in the bending direction of the distal end portion. And

Further, the flat part may extend to the bent part or a tip part on the tip side of the bent part.

Further, the cross section of the flat portion has a pair of opposing straight portions, and a track shape having a curved portion that bulges outward while connecting opposite ends of both ends of the pair of straight portions. good.

The material of the pin of the present invention is particularly effective for Au, Pd, Cu, Ag, or an alloy containing one or more of the above elements.

Also, in a very simple process, that is, a method for manufacturing a probe pin that has a bent part on the tip side and the most advanced part contacts the object to be measured.
A bending process that forms a bent part and a tip part on a straight wire, and a flat shape that is long in the bending direction of the tip part of the pin by rolling the range from the tip side of the body part to the bent part or the tip part. A rolling process for forming a part,
The probe pin can be manufactured by the method.

By adopting the form of the present invention, sufficient needle pressure can be stably obtained even when repeated contact is made. In addition, since a sufficient needle pressure can be obtained even with a soft metal such as a noble metal, it is possible to select a highly conductive material that is more advantageous for current inspection.

Furthermore, since the width can be reduced from the probe pin itself, particularly from the vicinity of the bent portion, it is possible to cope with the narrowing of the pitch of the electrode contacts to be measured.

Side view of the probe pin of the present invention Top view of the probe pin of the present invention Cross-sectional shape diagram of the flat part in the probe pin of the present invention Formation example of flat part in probe pin of the present invention Side view of conventional general probe pin Perspective view of a more rigid conventional probe pin Overview of needle pressure measurement test Relationship between push-in amount and needle pressure in needle pressure measurement test

A typical embodiment of the present invention is shown in FIGS. FIG. 1 is a lateral view of the probe pin of the present invention, and FIG. 2 is a top view of the probe pin of the present invention. The probe pin of the present invention includes at least a body portion 4, a flat portion 6, a bent portion 8, and a tip portion 10.

The cross-sectional shape of the body part 4 has the shape of the base material prepared in the manufacturing process of the probe pin of the present invention. In general, the cross section is round, but other cross sectional shapes may be processed. Moreover, since the trunk | drum 4 is generally fixed with a probe card with solder, you may process the surface of the trunk | drum 4 in the property which is easy to become familiar with solder.

The flat part 6 which is the principal part of this invention can be obtained by rolling the front end side of the trunk | drum 4, for example. When the flat part 6 is provided, the central axis 6 ′ of the flat part and the central axis 4 ′ of the body part do not necessarily coincide with each other. For example, in FIG. 2A, the central axis 6 'of the flat portion and the central axis 4' of the trunk portion are on the same line and coincide with each other. On the other hand, in FIG. 2B, the central axis 6 'of the flat part and the central axis 4' of the body part are not on the same line but are shifted from each other. Although both are in the form having the effect of the present invention, (a) is more preferable because the stress applied to the center axis 6 ′ or the center axis 4 ′ works equally on the left and right, but is not limited thereto. .

An example of the cross-sectional shape of the flat portion 6 in the probe pin of the present invention is shown in FIG. For example, when the cross section of the flat portion 6 has a round cross section of the base material, when it is rolled in one direction, a so-called track shape consisting of a pair of planes c1 and a pair of arcs c2 is formed as shown in (c). sell. Other examples of the cross-sectional shape of the flat portion 6 include (d) a rectangle, (e) a hexagon, and the like. The diagram shown in FIG. 3 is an example, and the present invention is not limited to these.

It is extremely important that the cross-sectional shape of the flat part 6 is long in the direction in which contact is repeatedly performed in any example. The ratio of the thickness a to the width b is preferably 1 <b / a ≦ 4. However, in order to obtain a desired needle pressure, the ratio may be appropriately designed according to various conditions such as the length of the probe pin and the hardness of the material. .

Further, the range in which the flat portion 6 is provided may be appropriately designed according to various conditions such as the total length of the probe pin and the hardness of the material. Specifically, when the body portion 4 is fixed to the probe card, for example, it is better to provide a wider portion than the fixed portion, for example, from the position of the pin base to the vicinity of the bent portion, but it is necessary to limit to this range Absent.

On the other hand, the range in which the cross-sectional shape is flattened as described above may extend to the bent portion 8. In that case, since the rigidity of the bent part 8 can be increased, it is possible to suppress the spread of the bent angle 8 ′ due to contact at the time of inspection and maintain stable measurement.

Further, the tip portion 10 may be rolled. In that case, since the width of the probe pin can be made thinner, it is possible to expect a narrow pitch when manufacturing the probe card. However, since the diameter of the most advanced portion 12 is generally very small, from several μm to several tens of μm, it is necessary to prevent the straightness from being lost by rolling.

The flat part 6 and the tip part 10 may be previously tapered. By doing so, it is possible to achieve a further narrower pitch of the tip portions 10 of the probe pins that are particularly densely packed, and it is possible to cope with a case where the distance between the electrode contacts that are the objects of measurement is narrower.

The method for manufacturing the probe pin of the present invention is as described above, but a more detailed example is shown using FIG. FIG. 4 is a diagram showing an example of forming a flat portion in the probe pin of the present invention. A pin 14 that has been previously tapered or bent at the tip of a base material is held by a chuck 14. In this state, the pin is plastically deformed by sandwiching the pressing jig 16 from above and below and further rolling, and the flat portion 6 can be formed.

A needle pressure measurement test was performed using the probe pin of the present invention and a conventional probe pin. As a probe pin used for measurement, the conventional one shown in FIG. 5 was prepared. An alloy containing Pd was selected as the material, and a round cross section was used. The diameter of the body portion was 0.1 mm, the tip portion was tapered, the taper length was 1.0 mm, and the tip portion diameter was 0.020 mm. Further bending was performed, the tip was 0.30 mm, and the bending angle was 100 °.

On the other hand, the probe pin of the present invention was subjected to a rolling process within a range of 2 mm from the bent part where the bending process was performed on the conventional pin, thereby forming a flat part. At this time, the flat portion was formed to have a maximum width of 0.15 mm and a thickness of 0.055 mm.

Using these two pins, a needle pressure measurement test was performed in the same state as in use as shown in FIG. The holder 18 holds the entire pin to be tested so that it is kept horizontal. At this time, the distance L from the tip of the pin to the tip of the holder is 1.5 mm. In this state, it is lowered vertically and the position in contact with the horizontal test floor is taken as the reference plane. Thereafter, the relationship between the further pushed distance (mm) and the obtained needle pressure (g) is shown in FIG.

When the stylus pressure is sufficiently small, there is not much difference from the conventional one, but the difference in stylus pressure obtained as the push-in amount increases increases proportionally. In order to obtain the needle pressure required for the contact test, for example, 6 g, the push amount of the conventional probe pin is required to be 0.17 to 0.18 mm. On the other hand, in the present invention, it may be about 0.11 to 0.12 mm. That is, when the needle pressure is lower than the pushing amount, the probe pin bends and absorbs the pushing force. In the present invention, it may be about 60% of the conventional pushing amount, and it can be seen that the pushing force is transmitted to the tip of the probe pin.

The present invention can be used not only for a probe card pin for conducting an electric current inspection but also for a scanning probe microscope or a contact type surface roughness meter that simply requires strength. That is, it can be applied to various pins and needles that require sufficient needle pressure and strength that can withstand repeated contact.

2... Probe pin 4... Body portion 6 .. flat portion 8... Bent portion 10.

Claims (5)

In the probe pin that has a bent part on the tip side and the most advanced part contacts the object to be measured,
A probe pin comprising: a body portion for fixing to a device to which the probe pin is attached; and a flat portion having a cross section from the distal end side of the body portion to the bent portion that is long in the bending direction of the distal end portion. 2. The probe pin according to claim 1, wherein the flat portion extends to the bent portion or a distal end portion that is closer to the distal end than the bent portion. The cross section of the flat portion is a track shape having a pair of opposing linear portions, and having curved portions that bulge outward while connecting the opposing ends of both ends of the pair of linear portions. 2. The probe pin according to 2. The probe pin according to any one of claims 1 to 3, wherein a material of the pin is Au, Pd, Cu, Ag, or an alloy containing one or more of the elements. In the manufacturing method of the probe pin which has a bent part on the tip side, and the most advanced part contacts the object to be measured,
A bending process that forms a bent part and a tip part on a straight wire, and a flat shape that is long in the bending direction of the tip part of the pin by rolling the range from the tip side of the body part to the bent part or the tip part. A method for producing a probe pin, comprising: a rolling step for forming a portion.