JP2002168879A - Insulation coated probe pin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an insulation coated probe pin to which an insulating coating of a uniform film thickness can be set and which fits to be finely arranged so that full insulation properties can be obtained by a small film thickness. SOLUTION: A body 10 of the probe pin 1 is formed of, e.g. tungsten. An Ni plating layer 13 is set to an outer surface of a pin trunk part 12 so as to obtain a solder testability, and the insulating coating 14 by electrodeposition coating is set from over the Ni plating layer 13. In the electrodeposition coating, electric charges at a part where the film thickness is small become relatively large, and film components are deposited there greatly. Therefore, the whole coating is eventually formed in the uniform film thickness, generating few pin holes and ensuring full insulation properties by the film thickness of 5-50 μm. Moreover, the pin trunk part 12 can be soldered to a printed wiring board 20 directly from over the insulating coating 14 and the insulating coating 14 is removed by heat at the soldering time, so that a fixing strength and energization are secured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention belongs to the technical field of probe pins arranged on a probe card for conducting a current test of an integrated circuit on a semiconductor wafer, and in particular, its insulating coating.

[0002]

2. Description of the Related Art In a manufacturing process of a semiconductor wafer constituting an integrated circuit such as an IC or an LSI, a probe card used for conducting a current test (wafer test) of an integrated circuit chip on the semiconductor wafer is mounted on a printed wiring board. Tens to hundreds of probe pins are arranged, mounted on a prober (inspection machine), and the tip of the probe pin is brought into contact with each electrode pad of the integrated circuit chip on the semiconductor wafer to conduct current measurement. Do.

[0003] For the probe pins provided on the probe card, tungsten, rhenium tungsten, beryllium copper or the like, which is hard and resilient, is conventionally used, and is particularly excellent in wear resistance and toughness. Tungsten is frequently used. Currently used probe cards are about 90% tungsten.

A probe pin made of tungsten or the like, for example, has a pointed tip, and the tip of the tapered portion contacts the electrode pad of the integrated circuit on the semiconductor wafer to be inspected from the middle of the tapered portion. The pin body, which is bent in a key shape and is not pointed, is connected to the printed wiring of the board by soldering. The pin body is plated with Ni for the purpose of improving solderability.

[0005] In the probe card, the pin pitch of the probe card has been narrowed due to the miniaturization of the integrated circuit formed on the semiconductor wafer, and the pin interval has become narrower. The problem of current leakage due to contact between pins has arisen. Therefore, as a countermeasure against leakage, it has been attempted to coat an insulating material on the pin surface by painting or the like, and to cover an insulating tube (resin tube) when the pin diameter is relatively large.

For example, JP-A-11-311639 describes a probe pin in which an insulating layer is formed on the outer periphery of a pin body by sputtering. In addition, JP-A-2
Japanese Patent Application Publication No. 000-155130 describes a technique in which a core wire constituting a pin main body is immersed in a polyimide liquid to adhere polyimide to the outer periphery. Japanese Patent Application Laid-Open No. 7-146309 describes a multi-wire probe in which a wire is coated with urethane. In addition, JP-A-10-14865
No. 1 discloses that a pin outer periphery is insulated with Teflon (registered trademark).

[0007]

As a countermeasure against the current leakage caused by the narrow pitch of the pin arrangement in the probe card, a resin tube or the like is covered with an insulating tube (resin tube) or the pin outer periphery is coated with a paint or the like. Attempts have been made to use an insulating coating by applying a resin tube.
As the pin diameter is reduced due to the narrow pitch of the pin arrangement, the working efficiency in the insulation process is significantly reduced, and
Since the thickness of the resin tube is as thick as about 40 μm, the fine arrangement of the pins is hindered.

[0008] As a coating technique, in addition to sputtering (welding method), after dipping a pin in a paint (resin) and pulling it up, sintering (baking / drying) of the paint is performed. There is spray coating (spray coating) that sprays (resin) in the form of a mist.
Although there is a vapor deposition method such as PVD, dipping and spray coating make it difficult to uniformly form a coating on the surface of a non-planar pin, resulting in poor uniformity of film thickness (variation ± 5).
５０50 μm), there are many occurrences of pinholes, there is a problem that insulation failure easily occurs, and there is a problem that it is easy to peel off at the time of bending processing. The same is true for sputtering, and the vapor deposition method is too expensive to be practical. There's a problem.

The present invention has been made in view of the above problems, and can provide an insulating film having a uniform film thickness.
An object of the present invention is to provide an insulating-coated probe pin suitable for a fine arrangement in which a sufficient insulating property can be obtained with a thin film thickness.

[0010]

SUMMARY OF THE INVENTION The present invention focuses on electrodeposition coating, which has not been used for insulating coating of probe pins, and solves the above-mentioned problem by performing insulating coating of probe pins by electrodeposition coating. It was found.

In other words, the insulating-coated probe pin of the present invention is a probe pin provided on a probe card for conducting a current test of an integrated circuit on a semiconductor wafer, and is provided on the outer surface of the pin body by electrodeposition coating. A film is provided.

In this case, the electrodeposition coating (electrophoresis) is used in principle for a base coating of a vehicle body for the purpose of rust prevention.
Alternatively, similarly to the method used in the field of manufacturing printed wiring boards as a means of coating a photoresist film on a substrate, a charged coating film component dispersed in water is electrophoresed and applied to a substrate surface (physical coating). In general, a substrate (pin) and an electrode are immersed in an electrode coating solution, and a voltage is applied between the substrate and the electrode.

As the electrodeposition coating solution, either a cationic or anionic type can be used.

The anionic electrodeposition coating liquid contains a coating component having an anionic group (carboxyl group, sulfonic acid group, phosphoric acid group, etc.).
By applying a voltage with the electrode on the coating device side as a negative electrode, the negatively charged coating film component (anion radical) migrates and bends on the surface of the substrate (pin) to form a coating film.

The cationic electrodeposition coating solution contains a coating component having a cationic group (organic ammonium group, pyridium group, etc.). By applying a voltage with the (pin) as the negative electrode, a positively charged coating film component (cation radical) migrates and bends out on the surface of the substrate (pin) to form a coating film.

In both the cationic electrodeposition coating liquid and the anionic electrodeposition coating liquid, the charge is relatively large where the film thickness on the substrate (pin) surface is small, and the film thickness is small. Since a large amount of the coating film component is deposited at a place where the electric charge is large, the film thickness is eventually uniform overall, and the occurrence of pinholes is small. The insulating film formed by electrodeposition coating has a film thickness of, for example, 10 to 10.
In the case of 15 μm, the variation is about ± 5 μm. The film thickness can be easily set by the energizing time or the like.

As described above, an insulating film having a uniform film thickness can be obtained by electrodeposition coating. For this reason, a large insulating property can be obtained with a thin film, and flexural peeling can be sufficiently dealt with by appropriately selecting a cationic group or an anionic group which is a coating component of the electrodeposition coating.
Since the thickness of the insulating film can be reduced, the fine arrangement of the probe pins is easy, and the degree of freedom in designing the pin arrangement is increased. In addition, the cost is lower than that of CVD or PVD.

Further, the above-mentioned insulating-coated probe pin of the present invention may be provided on a probe card, and the pin body may be fixed by soldering. Then, by reducing the film thickness and appropriately selecting a cationic group or an anionic group which is a coating film component of the electrodeposition coating, the insulating film at the soldering position is completely removed by heat at the time of soldering. It is preferable that the pin body and the probe card are secured and the conductivity is ensured. By doing so, soldering can be performed on the insulating film as it is, and an insulating-coated probe pin can be obtained regardless of the soldering position. In the case of covering with a conventional resin tube, it was necessary to cut a part of the tube for soldering, and in the case of dipping or spray coating, it was necessary to peel off part of the coating.

The thickness (film thickness) of the insulating film is 5 to 50 μm.
m is good. If the film thickness is too thin, uniformity cannot be ensured, insulation may be insufficient, and current leakage may occur. Also, if the film thickness is unnecessarily large, fine arrangement of pins may be hindered. Based on the usage conditions (voltage / current) of the probe pins, necessary insulation can be ensured at a film thickness of 5 μm or more. Further, a film thickness exceeding 50 μm is wasted. The insulating property can be sufficiently ensured even in the range of the film thickness of 5 to 20 μm.

Further, the body of the probe pin may be made of tungsten. In this case, a plating layer having solder wettability such as a Ni plating layer is provided on the tungsten of the pin body by electroplating or the like. It is preferable to provide an insulating film by electrodeposition coating on the plating layer.

[0021]

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

FIGS. 1 to 3 show an embodiment of the present invention. FIG. 1 is a plan view of a probe pin in a straight state before bending the tip, FIG. 2 is an enlarged sectional view on the tip side, and FIG. FIG. 5 is an explanatory view of soldering after bending of the tip.

In FIG. 1, reference numeral 1 denotes a probe pin disposed on a probe card of a type generally called a "horizontal needle type". The probe pins 1 are arranged at predetermined pitches (for example, 40 to 70 μm pitch) on the printed wiring board 20 of the probe card for inspecting the energization of the integrated circuit chip on the semiconductor wafer, and are soldered. Is what is done.

The probe pin 1 has a body 10 made of, for example, tungsten, a wire diameter of 0.1 to 0.7 mm, and a total length of 2 mm.
5 to 90 mm. The tip 11 of the probe pin 1 is sharpened in a linear taper shape over a predetermined length (for example, 0.3 to 6 mm).

The probe pin 1 is provided with an Ni plating layer 13 by electroplating on substantially the entire outer surface including the base end face of the pin body 12 having a constant diameter. An insulating film 14 is provided by electrodeposition coating so as to cover substantially the entire area of the Ni plating layer 13 including the end face. The Ni plating layer 13 is provided to improve the solder wettability of the pin body 12. The range of the insulating coating by the electrodeposition coating is not limited to the illustrated example, and at least the pin body 12 including at least the base end surface of the pin body 12 is provided.
Can be changed as appropriate within a range that can be a soldering position on the outer surface of the substrate.

In the electrodeposition coating, the probe pin 1 is placed in the electrodeposition coating solution.
This is performed by dipping the pin body 12 and the electrode and applying a voltage for a predetermined time. The electrodeposition coating liquid may be an anionic electrodeposition coating liquid containing a coating component having an anionic group such as a carboxyl group, a sulfonic acid group, and a phosphoric acid group. A cationic electrodeposition coating liquid containing a coating component having a cationic group may be used.

The thickness of the insulating film 14 is preferably about 5 to 50 μm. In both cases of the cationic electrodeposition coating liquid and the anion electrodeposition coating liquid, the charge is relatively large where the film thickness on the surface of the pin body 12 is thin, and is applied where the film thickness is small and the charge is large. When a large amount of the film component is formed, the film thickness becomes finally uniform over 5 μm or more. In addition, the occurrence of pinholes is small, sufficient insulation can be secured, and
For example, by setting the thickness to 50 μm or less, it is possible to cope with fine pin arrangement. The setting of the film thickness can be adjusted by setting the voltage and the energizing time.

As described above, the insulating property can be ensured by the insulating film 14 having a uniform thickness by the electrodeposition coating. Insulation can be sufficiently ensured with a film thickness of 5 to 20 μm.

In the probe pin 1 thus formed, from the straight state shown in FIG. 1 and FIG. (Not shown).

Then, each probe pin 1 after bending the tip is
The pin body 12 of each probe pin 1 is arranged in a circle at a predetermined position on the printed wiring board 20 with the front end 11 inside, and the base body end face, for example, as shown in FIG. Is the soldering position, and the printed wiring board 20 is
Are soldered to the respective electrodes. In FIG. 3, reference numeral 15 denotes a soldered portion.

In this case, when the thickness of the insulating film 14 is as thin as about 5 to 50 μm as described above, a cationic group or an anionic group which is a coating component of electrodeposition coating is appropriately selected. Even if the soldering is performed on the insulating film 14 as it is, the insulating film 14 at the soldering position is completely removed by the heat at the time of soldering, and the fixing strength and the electrical conductivity between the pin body 12 and the printed wiring board 20 are reduced. Secured. Therefore, the soldering can be directly performed on the insulating film 14 at an arbitrary position on the outer surface of the pin body 12 without being limited to the base end surface.

Further, the insulating film 14 by the electrodeposition coating
Can sufficiently cope with bending and peeling by appropriately selecting a cationic group or an anionic group. For example, it can also cope with a case where the base end of the pin body is bent 180 degrees and soldered to the back surface of the substrate.

In the above embodiment, the Ni plating is applied as the base plating, but the plating may be changed to the Cu plating or the like.

The present invention can also be applied to a probe pin made of a base material such as rhenium tungsten, beryllium copper or the like in addition to tungsten.

The present invention can be similarly applied to a probe pin whose tip is not pointed.

The present invention can be similarly applied to a probe pin disposed on a probe card of a type generally referred to as a "vertical needle type".

Further, the probe pin of the present invention may have a perfect circular cross section, or may have an irregular cross sectional shape other than a perfect circle. What is an irregular cross-sectional shape other than a perfect circle?
For example, a long circle (track shape), an elliptical shape, a rectangular shape, etc., and various other shapes can be adopted. The probe pin having the irregular cross-sectional shape may have an irregular cross section over the entire length of the probe pin, or may have a partially irregular cross section. As a probe pin having a partially irregular cross section, for example, there is a probe pin whose pin body has a perfectly circular cross section and whose tip section has an irregular cross section.

[0038]

As is clear from the above description, the insulating-coated probe pin of the present invention can provide an insulating film having a uniform film thickness by electrodeposition coating. Therefore, a sufficient thickness can be obtained without increasing the film thickness. Insulation can be ensured, and it can respond to bending peeling.

Further, the insulating film can be made thin, and it is easy to cope with fine pin arrangement. Since the insulating film formed by electrodeposition coating can secure sufficient insulation at a film thickness of 5 to 20 μm, it becomes easier to make the pin arrangement finer than in the case of using a thick resin tube having a thickness of about 40 μm,
Further, the cost can be reduced as compared with an insulating film formed by CVD or PVD.

Further, the soldering can be performed on the insulating film as it is, and the working efficiency can be greatly improved.

[Brief description of the drawings]

FIG. 1 is a plan view showing a straight state before bending a tip of a probe pin according to an example of an embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view of the probe pin shown in FIG.

FIG. 3 is an explanatory view of soldering after bending the tip of the probe pin shown in FIGS. 1 and 2;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Probe pin 10 Main body 11 Tip part 12 Pin body 13 Ni plating layer 14 Insulating film (electrodeposition coating) 15 Solder part 20 Printed wiring board

Claims (7)

[Claims] 1. A probe pin disposed on a probe card for conducting electricity of an integrated circuit on a semiconductor wafer, wherein an insulating film by electrodeposition coating is provided on an outer surface of the pin body. Insulated probe pin. 2. A probe pin which is provided on a probe card for conducting an electric current test of an integrated circuit on a semiconductor wafer and whose pin body is fixed by soldering, wherein the outer periphery of the pin body is insulated by electrodeposition coating. An insulated probe pin characterized by having a coating. 3. The insulating-coated probe pin according to claim 2, wherein the insulating film at the soldering position is removed by heat at the time of soldering, so that the pin body and the probe card are fixed and the electrical conductivity is ensured. 4. The probe pin according to claim 1, wherein said insulating film has a thickness of 5 to 50 μm. 5. The method according to claim 2, wherein the material of the main body is tungsten, a plating layer having solder wettability is provided on the tungsten of the pin body, and the insulating film is provided on the plating layer. 4. The insulated probe pin according to 1. 6. The insulated probe pin according to claim 5, wherein the plating layer is a Ni plating layer. 7. The probe pin according to claim 6, wherein the Ni plating layer is an electroplating layer.