JPH0816683B2 - Manufacturing method of probe needle - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for testing an electronic circuit on a semiconductor wafer (probe card), a device for inspecting a packaged IC (IC socket), and a device for electrically testing a liquid crystal substrate. The present invention relates to a method for manufacturing a probe needle used for such purposes.

[0002]

2. Description of the Related Art FIG. 8 is a front view showing a conventional method for manufacturing a probe needle. Diameter is, for example, 0.25m
m of the tungsten wire 10 is connected to the etching solution 1
The tip of the wire rod 10 can be made into a conical shape by immersing it in 2, then lifting it up and repeating this many times. This is used as a probe needle. The wire rod 10
May be bent into a predetermined shape in advance and then the tip may be immersed in the etching solution 12.

[0003]

When the probe needle is manufactured by the above-mentioned etching method, there are the following problems. First, since it needs to be dipped in the etching solution many times, it takes a very long time to finish it into a predetermined conical shape. For example, dipping is repeated for about 1 hour until one wire is finished. In practice, many wires are attached to the jig and etching work is performed at the same time.
Although the production time per book is shortened, the production capacity is still about several tens per hour.

Further, in the above-mentioned etching method, there are large variations in the shape when finished in a conical shape and variations in the radius of curvature of the tip portion, and it is difficult to control this. If the cross-sectional dimension at a certain distance from the tip is thick or thin, the following problems occur. In recent semiconductor electronic circuits, miniaturization is progressing, and many probe needles are arranged in a very high density in a probe card. In this case, if the thickness near the tip of the probe needle is not within the predetermined dimension, there is a risk that adjacent probe needles will contact each other. Further, the probe needle contacts the circuit with a predetermined contact pressure due to its own spring property, but if the cross-sectional dimension of the probe needle is different for each probe needle, the spring constant also changes and the contact of the probe needle The pressure will vary.

Further, if the radius of curvature of the tip portion of the probe needle varies, the following problems occur. When the probe needle is brought into direct contact with the wiring portion of the miniaturized electronic circuit, the radius of curvature of the tip portion of the probe needle needs to be equal to or less than the wiring width. Therefore, the probe needle having the specifications in which the radius of curvature of the tip portion of the probe needle is designated is manufactured. In this case, the etching method cannot precisely control the radius of curvature of the tip of the manufactured probe needle. Therefore, by measuring the radius of curvature of the manufactured probe needle and classifying the probe needle for each curvature radius, The present condition is that the specification of the radius of curvature is satisfied, and thus the yield is poor in this method.

In addition to the above-mentioned etching method, there is a manufacturing method by cutting (or grinding). Also in this case,
There is a large variation in the fine shape of the tip of the probe needle, and the production capacity cannot be improved so much.

In addition, the etching method and the cutting method have a drawback that the smaller the tip portion of the probe needle, the weaker the strength.

The present invention has been made to solve the above problems, and an object thereof is to provide a manufacturing method capable of manufacturing a probe needle having a stable dimension with high productivity. It is in.

[0009]

Means and Actions for Solving the Problems The method for manufacturing a probe needle according to the first invention comprises the following steps. (A) A pressing step in which a part of the wire material is crushed by press working to form an inclined portion with a changed thickness. (B) A cutting step of cutting at least both sides of the inclined portion in the width direction. Generally, a wire having a circular cross section is used, but a wire having a cross section other than a circle may be used. Taking a wire having a circular cross section as an example, a wire having a diameter of about 0.1 to 0.3 mm can be used.
The thinnest portion of the inclined portion corresponds to the tip of the probe needle and is made much thinner than the cross-sectional dimension of the wire. The thickness of the thinnest part is, for example, 25 to
50 μm. When the wire rod is crushed by press working, for example, two flat surfaces are formed and both are inclined with respect to each other. If the two flat surfaces are inclined symmetrically with respect to the center line of the wire rod, a so-called tapered shape is obtained. Note that one flat surface may be parallel to the center line of the wire and only the other flat surface may be inclined. The crushed sloping portion expands laterally beyond the original cross-sectional dimension of the wire. Therefore, the shape suitable for the probe needle is obtained by cutting both sides of this inclined portion.

As described above, by using the pressing process and the cutting process, compared with the conventional etching method,
The productivity when manufacturing the probe needle is greatly improved.
By performing the pressing step and the cutting step in sequence with one press machine, it is possible to easily manufacture about 100 probe needles per minute. Therefore, as compared with the conventional method, the productivity is improved about 100 times, for example. Further, since the shape near the tip of the probe needle is formed by the pressing step and the cutting step by the press, the variation in the shape is reduced as compared with the conventional etching method.

According to a second aspect of the present invention, in the first aspect of the present invention, in the pressing step, the wire material is crushed in the middle by press working, and in the cutting step, both sides in the width direction of the inclined portion are cut and the thickness of the inclined portion is the most. The thin part is cut perpendicular to the wire. That is, according to the present invention, an inclined portion is formed in the middle of the wire so that the thinnest portion finally becomes the tip of the probe needle. Therefore, in the cutting step, in addition to cutting both sides of the inclined portion in the width direction, the thinnest portion is cut perpendicularly to the wire rod. When the wire rod is crushed in the middle, the force acting in the longitudinal direction of the wire rod when crushing is smaller than that when the end portion of the wire rod is crushed to form an inclined portion.
It doesn't have to be unidirectional. Also, since the wire itself is very thin, cutting only the two sides of the inclined part will result in very small cutting scraps, which is difficult to process.
If both sides of the slanted portion and the remaining wire rod portion are integrated and cut, the cutting waste becomes a certain size to facilitate the processing.

A third aspect of the present invention adds a bending step of bending the wire material halfway after the cutting step of the first aspect. The probe needle may be straight or may be bent once or a plurality of times in the middle, depending on the mounting mode. Therefore, the probe needle is bent if necessary.

In a fourth aspect of the invention, in the first or third aspect of the invention, as a final step, an etching step of immersing at least a portion to be the tip of the probe needle in an etching solution is added. Burrs and the like are present in the portion that has undergone the pressing step and the cutting step, but this burr can be removed by performing a short-time etching step.
Further, the shape of the tip of the probe needle can be made smooth.

A fifth invention is characterized in that, in the first or second invention, the wire is cut into a predetermined length at the base side of the probe needle at the same time as the cutting step. Thereby, the length of the probe needle is set to a predetermined dimension.

According to a sixth aspect of the present invention, in the cutting step of the first aspect, both sides of the inclined portion are linearly cut so that the width becomes narrower as the thickness becomes thinner. That is,
The width of the sloping part is tapered. As a result, the vicinity of the tip of the probe needle has the shape of a truncated pyramid having a rectangular cross section.

In a seventh aspect of the present invention, in the cutting step of the first aspect of the present invention, both sides of the inclined portion are cut in parallel so as to have a width approximately equal to the cross-sectional dimension of the wire. This allows
The vicinity of the tip of the probe needle has a chisel shape having the same width as the original wire.

In the eighth invention, the wire material is beryllium copper. If tungsten, which is normally used as the probe needle, is used, there is a possibility that defects such as cracks may occur during the pressing step by press working. On the other hand, beryllium copper is more ductile than tungsten and less likely to cause defects such as cracks. Further, when beryllium copper is used as the probe needle, the contact resistance does not become so large even if an oxide film is formed at the tip of the probe needle, as compared with tungsten. The beryllium copper used in the present invention is, for example, JIS (JIS H 32
A general beryllium copper strip defined in 70) can be used.

In a ninth aspect of the present invention, the wire rod has a vertically elongated cross section. This increases the bending strength when the probe needle is used, as compared with a wire having a circular cross section.

[0019]

FIG. 1 is a perspective view showing a manufacturing process for manufacturing a probe needle using an embodiment of the method of the present invention. First, as shown in (A), a beryllium copper wire 14 having a circular cross section with a diameter of 0.25 mm is cut into an appropriate length. Hereinafter, this step is referred to as a blanking step. Next, as shown in (B), the wire 14 is pressed at a distance from the one end 16 of the wire 14 to some extent.
Crush. Hereinafter, this step is referred to as a pressing step. As a result, the inclined portions 18 and 20 are formed. The inclined portion 18 has a flat upper surface and a lower surface that are inclined in opposite directions with respect to the center line of the wire 14. That is, the inclined portion 18 is tapered when viewed from the side surface direction. Therefore, the thickness linearly increases from the thinnest portion 22 of the inclined portion 18 (boundary portion with the inclined portion 20) to the thickest portion 24 of the inclined portion 18. The width of the inclined portion 18 is larger than the diameter of the wire 14. The thinnest portion 22 has a thickness of 25 to 50 μm.
The length of the inclined portion 18 in the longitudinal direction is 1 to 3 mm. Therefore, the angle between the upper surface and the lower surface of the inclined portion 18 is 5 to
It is 15 degrees. The upper surface and the lower surface of the inclined portion 18 are not limited to flat surfaces and may be curved surfaces that are convex or concave outward.

The other inclined portion 20 has the same shape as the inclined portion 18. Only one sloped portion 18 will be used as the tip of the probe needle and the other sloped portion 20 will be removed by the cutting process described below. The inclined portion 20 which becomes cutting waste is also formed in the pressing step for the following reason. Although it is possible to form only one inclined portion 18 so that one end 16 of the wire is thinnest, in this case, a force acts on the wire 14 only in one direction (right direction in the figure) during the pressing step. Resulting in. Then, it becomes relatively difficult to hold the wire rod and maintain the processing accuracy during the pressing step. On the other hand, if the two inclined portions 18 and 20 are formed symmetrically in the longitudinal direction of the wire 14 as shown in FIG.
This is convenient because the forces applied in the longitudinal direction of the wire during the pressing step are balanced. Further, when the inclined portion 20 exists,
It also facilitates the treatment of cutting chips generated in the cutting step described later.
This will be described later.

Next, as shown in FIG.
Cut both sides in the width direction. Hereinafter, this step is referred to as a cutting step. FIG. 2 is an enlarged plan view showing this cutting step. In FIG. 2A, both sides of the inclined portion 18 in the width direction are cut to form two side surfaces 26 and 28.
At the same time, at the thinnest portion 22, the wire 14 is cut perpendicularly. Thereby, the tip 30 is formed. The two side surfaces 26, 28 are inclined in directions opposite to each other with respect to the center line of the wire rod 14, so that the width of the inclined portion 18 is tapered. As a result, the inclined portion 18 becomes narrower in width as the thickness becomes thinner, and becomes a truncated pyramid shape having a rectangular (almost square) cross section. The width of the tip 30 is 25-
It is 50 μm. In addition, in this cutting step, as shown in FIG.
As shown in (C), the root 25 side of the wire 14 is also cut,
It has a predetermined length. The side surfaces 26 and 28 are not limited to flat surfaces, but may be curved surfaces that are convex or concave outward.

When the cutting is performed as described above, both side portions of the inclined portion 18 are attached to the other inclined portion 20 side, and in this state, it becomes cutting waste. Since this cutting waste has a size to a certain extent as compared with the case where only the both sides of the inclined portion are used as the cutting waste alone, the subsequent processing becomes easier.

Returning to FIG. 1, the wire 1 after the cutting process is completed.
No. 4, as shown in (D), is bent almost vertically behind the inclined portion 18. Alternatively, it is bent in the middle of the inclined portion 18. Hereinafter, this step is referred to as a bending step. This bending step can be omitted or bending can be performed at two or more places depending on the attachment mode of the probe needle. For example, FIG. 3A shows a straight needle in which the bending step is omitted. FIG. 3B shows a probe needle which is bent only once behind the inclined portion. FIG. 3C shows a probe needle bent at two places.

The probe needle after the bending step is finally subjected to the etching step. That is, the tip portion of the probe needle is immersed in the etching solution for a short time to smooth the shape of the tip portion and remove burrs and the like.

By the way, the shape near the tip of the probe needle is not limited to the shape of a truncated pyramid as shown in FIG. FIG. 4 is a part of a process for manufacturing a flea-shaped probe needle, and FIGS. 4B and 4C are the same as FIGS.
Corresponding to. In this example, the width of the tip 30 is made substantially the same as the diameter of the wire 14 by cutting both sides of the inclined portion 18 in parallel. An enlarged plan view of the cutting step at this time is shown in FIG. The two side faces 26 and 28 are parallel to each other.

FIG. 5 is a perspective view showing still another embodiment. In this example, in the pressing step (B), the wire rod 1
One inclined part 18 so that the tip 16 of 4 is the thinnest
Only forming. That is, the other inclined portion 20 shown in FIG. 1 does not exist. By doing so, it is possible to finally manufacture a probe needle having the same shape as in FIG. This method is effective when it is desired to reduce cutting waste as much as possible, such as when using an expensive wire rod. However, it is inferior to the method shown in FIG. 1 in terms of a problem of balance of forces in the longitudinal direction of the wire rod 14 in the pressing step and a problem of processing cutting waste in the cutting step.

FIG. 6 is a plan view showing a schematic arrangement of a press device for carrying out the method of the present invention. The press machine has a turntable 32. This turntable 3
The wire rod is placed on No. 2 so that the wire rod can be sequentially moved to each of the processing stages A to D. In stage A, a blanking process is performed. That is, the wire rod 14 drawn from the feeder 34 is cut into an appropriate length. The pressing process is performed on the stage B, the cutting process is performed on the stage C, and the bending process is performed on the stage D. When the bending process is completed, the wire rod is discharged into the bucket 36. The probe needles can be continuously manufactured by sequentially performing each of these steps. The production capacity is about 100 pieces per minute. The yield is almost 100%. In this turntable 32, one round is divided into six, and six processing stages are provided. Four of these stages are used for processing, and the rest are spare stages.

Although the work of the press machine is completed as described above, the etching step is carried out thereafter to finally complete the probe needle.

In the above-mentioned embodiment, the wire rod used as the material of the probe needle has a circular cross section, but it may have a cross sectional shape other than the circular shape. In particular, it is effective to make the cross-sectional shape of the wire lengthwise in order to increase the bending strength when the probe needle is used. FIG. 7A is a side view when the probe needle is used. When the load W acts on the tip of the probe needle, the deflection δ is generated at the tip of the probe needle. This deflection δ depends on the length of the probe needle, the longitudinal elastic modulus, and the cross-sectional shape. Comparing under the same conditions other than the cross-sectional shape and the same cross-sectional area of the wire rod, a probe needle made of a vertically elongated wire rod is better than a probe needle made of a wire rod with a circular cross-section. However, the deflection δ is small. Therefore, the latter probe needle has a higher bending strength during use. 7B is a sectional view taken along line BB of FIG. In this example, the wire rod has an oval cross section. (C)
And (D) are other examples of cross-sectional shape, (C) is elliptical,
(D) is a rectangle. In each of the cases (B) to (D), the cross-sectional shape is vertically long and the bending strength is larger than that of the circular shape. Note that, for example, in order to obtain the cross-sectional shape of (B), there is a method of preparing a wire having an oval cross-section in advance, and a method of pressing a wire having a circular cross-section into the cross-sectional shape of (B). In order to carry out the latter method, in the pressing apparatus shown in FIG. 6, a processing stage for changing the circular cross section into a vertically long cross section may be provided in front of the processing stage A.

The present invention is not limited to the above embodiment, but the following modifications are possible. (1) The size of the wire 14 and the size of the inclined portion 18 are not limited to those in the above-described embodiment, and can be arbitrarily changed according to the application of the probe needle. (2) The arrangement of the press device may employ another work feeding device instead of the above-mentioned turntable system.

[0031]

According to the present invention, since the probe needle is manufactured by using the pressing step and the cutting step, the fine shape of the tip portion of the probe needle is different in size from the conventional etching method. Can be manufactured with less. Moreover, since the pressing process and the cutting process can be carried out by a single action by the press machine, the production capacity is greatly improved. Furthermore, if the crushing by the pressing process is used,
Since the tissue is continuous to the tip of the probe needle without being cut, the tip is tougher than the probe needle made by the etching method or the cutting method.

[Brief description of drawings]

FIG. 1 is a perspective view showing a process of one embodiment of the present invention.

FIG. 2 is a plan view of a cutting process.

FIG. 3 is a side view showing various examples of a bending process.

FIG. 4 is a perspective view showing another example of a cutting process.

FIG. 5 is a perspective view showing a process of another embodiment of the present invention.

FIG. 6 is a plan view showing the arrangement of a press device.

FIG. 7 is a side view showing the deflection of the probe needle and a cross-sectional view of the probe needle.

FIG. 8 is a front view showing a conventional manufacturing process.

[Explanation of symbols]

 14 ... Wire material 18 ... Inclined part 22 ... Thinnest part

Claims (8)

[Claims] 1. A method of manufacturing a probe needle, comprising the following steps. (A) The thinnest wire is crushed by pressing in the middle.
A pressing step of forming two inclined portions having different thicknesses in the longitudinal direction with the other portion interposed therebetween . (B) Width of one of the two inclined portions
Work to cut both sides of the direction and wire the thinnest part
A cutting process for simultaneously performing the work of cutting vertically . 2. The method of manufacturing a probe needle according to claim 1, further comprising a bending step of bending the wire material halfway after the cutting step. As 3. A final step, the manufacturing method of the probe needle according to claim 1 or 2, characterized in that the addition of an etching step of immersing the portion to be a tip of at least the probe needles to the etching solution. 4. The method of manufacturing a probe needle according to claim 1, wherein the wire is cut into a predetermined length at the base side of the probe needle at the same time as the cutting step. 5. The method of manufacturing a probe needle according to claim 1, wherein in the cutting step, the both sides are cut linearly so that the width becomes narrower as the thickness becomes thinner. 6. The method of manufacturing a probe needle according to claim 1, wherein, in the cutting step, the both sides are cut in parallel so as to have a width approximately equal to a cross-sectional dimension of the wire. 7. The method for manufacturing a probe needle according to claim 1, wherein the wire material is beryllium copper. 8. The method of manufacturing a probe needle according to claim 1, wherein the wire rod has a vertically long cross-sectional shape.