JP7471148B2 - Probe needle and probe unit - Google Patents

Description

The present invention relates to a probe needle and a probe unit for use in testing electrical continuity tests of electronic components, circuit boards, etc.

In recent years, various circuit boards have been widely used, such as high-density mounting boards used in mobile phones, and IC package boards such as BGA (Ball Grid Array) and CSP (Chip Size Package) built into personal computers. Such circuit boards are inspected for their electrical characteristics before and after mounting, for example, by measuring DC resistance and conducting continuity tests. The inspection of electrical characteristics is performed using a jig for an inspection device (hereinafter referred to as a "probe unit") connected to an inspection device that measures electrical characteristics, for example, by contacting the tip of a pin-shaped probe needle attached to the probe unit with an electrode of the circuit board (hereinafter also referred to as the "subject to be measured"). The probe needle is composed of a metal conductor and an insulating coating provided on at least the area other than both ends of the metal conductor.

Patent Document 1 proposes a shape and a manufacturing method for efficiently manufacturing such a probe needle. The shape and manufacturing method of the probe needle are as follows: in a contact probe having an insulating coating on the outer periphery of a pin-shaped metal conductor, (1) one or both ends of the probe have a shape consisting of a processed end face of the metal conductor and a processed end face of the insulating coating, and the shape of the end is selected from a hemispherical shape, a conical shape, a conical shape with a hemispherical tip, and a conical shape with a flat tip; and/or (2) one or both ends of the probe are formed by a processed end face of the metal conductor whose tip is exposed by grinding, and a processed end face of the insulating coating that is ground simultaneously with the processed end face of the metal conductor and has a shape that conforms to the shape of the processed end face of the metal conductor.

JP 2007-322369 A

Patent document 1 proposes various shapes for the tip of the probe needle. However, as shown in Figure 3 of Patent document 1, if the end shape of the insulating coating is a tapered shape that is an extension of the processed end face shape of the metal conductor, the exposed part of the metal conductor becomes small, and there is a possibility that a contact failure will occur between the tip of the metal conductor and the electrode part on the inspection device.

In addition, if the shape of the end of the insulating coating is machined to be almost perpendicular to the longitudinal direction, there is a risk that the edge of the end of the insulating coating may easily get caught when inserting a probe needle into a guide hole in a guide plate on the inspection device side.

In addition, in the probe unit, in order to make the probe needle bend in a fixed direction, the probe needle may be tilted, for example, by about 0.5 to 5 degrees, so that the tip of the probe needle contacts the electrode on the inspection device at an angle. In this case, the edge of the end of the insulating coating may come into contact with the inner surface of the guide hole, and repeated sliding during inspection may cause problems such as the insulating coating peeling off from the probe needle or the edge of the insulating coating scratching the inner surface of the guide hole. Also, as shown in Figure 3 of Patent Document 1, if the length of the exposed tip of the metal conductor is short, there is a risk of poor contact with the electrode.

The present invention has been made to solve the above problems, and its purpose is to provide an easily manufactured probe needle and probe unit that is used primarily for continuity testing of electronic components, circuit boards, etc., and that has an end shape on the side of the testing device that is less likely to cause the edge of the insulating coating to get caught on the inner surface of the guide hole in the guide plate (hereinafter referred to as the "support plate" in this application) and that can reliably contact the electrode part on the side of the testing device.

(1) The probe needle according to the present invention is a probe needle having a body part with an insulating coating on the outer periphery of a pin-shaped metal conductor, and ends at both ends of the metal conductor that do not have the insulating coating, characterized in that the metal conductor has a curved tip shape, the radius of curvature of the curved surface is R1, the outer diameter of the metal conductor is D1, and the length of the end is L1, and the insulating coating has a curved end shape in the longitudinal direction, the radius of curvature of the curved surface is R2, the outer diameter of the body part is D2, the longitudinal length of the curved surface is L2, and the thickness is T1, where R1<(D1/2)<L1 for the metal conductor, and R1<R2<(D2/2) and L2>T1 for the insulating coating.

According to this invention, (a) the radius of curvature R1 of the tip of the metal conductor is smaller than the radius of the metal conductor (D1/2), and the length L1 of the exposed end of the metal conductor in the longitudinal direction is larger than the radius of the metal conductor (D1/2), so that the exposed end of the metal conductor is longer, and the contact between the tip of the probe needle and the electrode part on the inspection device side is improved. As a result, it is possible to eliminate contact problems between the two. In addition, (b) the end of the insulating coating is curved rather than at a right angle, so that when the probe needle is inserted into the guide hole, there is no corner at the end of the insulating coating, and the edge of the end of the insulating coating is less likely to get caught. In addition, (c) the radius of curvature R2 of the end of the insulating coating 2 is larger than the radius of curvature R1 of the tip of the metal conductor, smaller than the radius of the body part (D2/2), and the length L2 of the longitudinal direction of the end of the insulating coating is larger than the thickness T1 of the insulating coating, so that even if the probe needle inserted into the guide hole of the support plate on the inspection device side is tilted, the end of the insulating coating will contact the inner surface of the guide hole. As a result, even if repeated inspections cause sliding contact between the inner surface of the guide hole and the edge of the insulating coating of the probe needle, peeling of the insulating coating can be prevented, and defects such as damage to the inner surface of the guide hole can be prevented.

In the probe needle according to the present invention, it is preferable that the outer diameter of the metal conductor is in the range of 8 μm to 180 μm, and the outer diameter of the body is in the range of 10 μm to 200 μm.

In the probe needle according to the present invention, it is preferable that the thickness of the insulating coating is in the range of 1 μm or more and 10 μm or less.

(2) A probe unit according to the present invention includes a support plate arranged on the side of a measured object, a support plate arranged on the side of an inspection device, and probe needles attached to guide holes provided in at least two of the support plates, the probe needles contacting the inner surface of the guide hole of either of the support plates and a tip of a metal conductor constituting the probe needle being brought into contact with an electrode of the measured object,
The probe needle has a body portion having an insulating coating on the outer periphery of a pin-shaped metal conductor, and ends at both ends of the metal conductor that do not have the insulating coating, wherein the metal conductor has a curved tip shape, the radius of curvature of the curved surface is R1, the outer diameter of the metal conductor is D1, and the length of the end is L1, and the insulating coating has a curved end shape in the longitudinal direction, the radius of curvature of the curved surface is R2, the outer diameter of the body portion is D2, the longitudinal length of the curved surface is L2, and the thickness is T1, where R1<(D1/2)<L1 for the metal conductor, and R1<R2<(D2/2) and L2>T1 for the insulating coating.

According to this invention, since the probe needle according to the present invention is provided, the exposed tip of the metal conductor is longer, and the contact between the tip of the probe needle and the electrode part on the inspection device side is improved. As a result, contact problems between the two can be eliminated. In addition, when the probe needle is inserted into the guide hole, the end of the insulating coating has no corners, and the edge of the end of the insulating coating is less likely to get caught. Even if the probe needle inserted into the guide hole of the support plate on the inspection device side is tilted, the end of the insulating coating will come into contact with the inner surface of the guide hole, so even if the inner surface of the guide hole and the edge of the end of the insulating coating of the probe needle come into sliding contact with each other during repeated inspections, peeling of the insulating coating can be prevented, and problems such as damage to the inner surface of the guide hole can be prevented.

The present invention provides an easily manufacturable probe needle and probe unit that is used primarily for continuity testing of electronic components, circuit boards, etc., and that is shaped such that the peripheral edge of the insulating coating is unlikely to get caught on the inner surface of the guide hole in the support plate and that can reliably contact the electrode part on the testing device.

FIG. 2 is an explanatory diagram showing an example of a probe needle according to the present invention. FIG. 2 is an explanatory diagram showing an example of a probe unit according to the present invention. 3 is a cross-sectional view for explaining the dimensions and shape of a probe needle according to the present invention. FIG. FIG. 13 is a diagram showing a state where an insulating coating of an inclined probe needle comes into contact with a guide hole. FIG. 13 is a diagram showing a conventional configuration in which an insulating coating of an inclined probe needle comes into contact with a guide hole.

The probe needle and probe unit according to the present invention will be described with reference to the drawings. Note that the embodiment described below is an example of the technical idea of the present invention, and the technical scope of the present invention is not limited to the following description and drawings, but includes inventions with similar technical ideas.

[Probe needle]
1 to 3, the probe needle 10 according to the present invention has a body 6 having an insulating coating 2 on the outer periphery of a pin-shaped metal conductor 1, and ends 3 at both ends of the metal conductor 1 that do not have the insulating coating 2. Its features are that in the probe needle 10 that contacts the inner surface 32 of the guide hole 31 of the support plate 30, the metal conductor 1 has a curved tip 1b with a radius of curvature R1, an outer diameter of the metal conductor 1 with a length L1, and the insulating coating 2 has a curved end 7b in the longitudinal direction Y with a radius of curvature R2, an outer diameter of the body 6 with a length L2 in the longitudinal direction Y of the curved surface, and a thickness T1, where R1<(D1/2)<L1 for the metal conductor 1 and R1<R2<(D2/2) and L2>T1 for the insulating coating 2.

In this probe needle 10, (a) the radius of curvature R1 of the tip 1b of the metal conductor 1 is smaller than the radius (D1/2) of the metal conductor 1, and the length L1 in the longitudinal direction Y of the exposed end 3 of the metal conductor 1 is larger than the radius (D1/2) of the metal conductor 1, so that the exposed tip of the metal conductor 1 is longer, improving the contact between the tip 1b of the probe needle 10 and the electrode 51 on the inspection device side. As a result, contact problems between the two can be eliminated.

In addition, (a) the end of the insulating coating is curved rather than at a right angle, so that when the probe needle is inserted into the guide hole, there are no corners at the end of the insulating coating, and the edge of the end of the insulating coating is less likely to get caught.

In addition, (c) the radius of curvature R2 of the end of the insulating coating 2 is made larger than the radius of curvature R1 of the tip of the metal conductor and smaller than the radius of the body (D2/2), and the longitudinal length L2 of the end of the insulating coating is made larger than the thickness T1 of the insulating coating, so that even if the probe needle inserted into the guide hole in the support plate on the inspection device is tilted, the end of the insulating coating will come into contact with the inner surface of the guide hole. As a result, even if repeated inspections cause sliding contact between the inner surface of the guide hole and the periphery of the end of the insulating coating of the probe needle, peeling of the insulating coating can be prevented, and defects such as damage to the inner surface of the guide hole can be prevented.

Each component will be explained in detail.

As shown in Figs. 1 to 3, the probe needle 10 is a probe needle whose tip 1b contacts the inner surface 32 of the guide hole 31 of the second support plate 30 on the inspection device side that constitutes the probe unit 60. The form of the probe unit 60 on the object to be measured is not particularly limited, but in the following description, an example can be given in which the end 7a of the insulating coating 2 contacts the periphery of the guide hole in the first support plate 20 and the tip 1a of the metal conductor 1 contacts the electrode 12 of the object to be measured 11.

The tip 1b refers to the tip of the probe needle on the side where the end of the insulating coating of the probe needle contacts the inner surface of the guide hole of the support plate constituting the probe unit. In the example of FIG. 2, it refers to the tip of the probe needle 10 on the inspection device side when the end 7b of the insulating coating 2 of the probe needle 10 contacts the inner surface 32 of the guide hole 31 of the second support plate 30 constituting the probe unit 60. On the other hand, the tip 1a refers to the tip of the probe needle on the side where the end of the insulating coating of the probe needle contacts the peripheral edge of the guide hole of the support plate constituting the probe unit. In the example of FIG. 2, it refers to the tip of the probe needle 10 on the measured object side when the end 7a of the insulating coating 2 of the probe needle 10 contacts the peripheral edge of the guide hole 21 of the first support plate 20 constituting the probe unit 60.

(Metal conductor)
The metal conductor 1 is a pin-shaped conductor processed to a predetermined length, and is formed by cutting a metal wire (also called a "metal spring wire") having high conductivity and high elasticity. Metals used for the metal conductor 1 include metals having a wide elastic range, such as copper alloys such as silver-copper alloys, tin-copper alloys, and beryllium-copper alloys, palladium alloys, tungsten, rhenium-tungsten, and steel (e.g., high-speed steel: SKH). In particular, tungsten, rhenium-tungsten, and the like, which have high strength characteristics and can be made thin, are preferred, as shown in the examples described below.

The metal conductor 1 is usually subjected to plastic processing such as cold or hot wire drawing until the metal becomes a linear conductor of a specified diameter. The outer diameter D1 of the metal conductor 1 is required to be made thinner in response to recent demands for narrower pitches, and can be arbitrarily selected within the range of 8 μm or more and 120 μm or less, preferably within the range of 10 to 110 μm, depending on the gap between adjacent probe needles 10 in the probe unit 60.

At the end 3 of the metal conductor 1 (part where the insulating coating 2 is not provided), a plating layer may be provided on the end 3 as necessary to suppress an increase in the contact resistance value between the metal conductor 1 and the electrode 12 or the lead wire 50 of the inspection device. Examples of metals that form the plating layer include metals such as nickel, gold, and rhodium, and alloys such as gold alloys. The plating layer may be a single layer or multiple layers. A preferred example of a multiple-layer plating layer is a gold plating layer formed on a nickel plating layer. The plating layer is usually formed after cutting the metal conductor 1 on which the insulating coating 2 is formed, peeling off the insulating coating 2, and processing the end of the metal conductor 1. Such a plating layer may be provided only on the end 3, but may also be provided on the entire metal conductor 1 before providing the insulating coating 2.

In order to facilitate attachment of the probe needle 10 to the probe unit 60 and to prevent the movement of the probe needle 10 from being hindered by the tip 1a of the probe needle 10 getting caught on the periphery of the guide hole 21 of the first support plate 20 when the probe unit 60 is in use, it is preferable that the straightness of the metal conductor 1 is high, and more specifically, the straightness is preferably 1000 mm or more in terms of the radius of curvature R.

(Shape of end)
The shape of the tip 1a of the metal conductor 1 on the side of the object to be measured is not particularly limited, and may be any shape selected from a hemispherical shape, a conical shape, a conical shape having a hemispherical tip, a conical shape having a flat tip, etc. The terms "semispherical shape" and "conical shape" used here include exact hemispheres and cones, but also approximate cones and approximate hemispheres.

On the other hand, the shape of the tip 1b of the metal conductor 1 on the inspection device side is curved, as shown in FIG. 3. The curved surface only needs to have a predetermined radius of curvature R1, which is smaller than the radius (D1/2) of the metal conductor 1, and the length L1 in the longitudinal direction Y of the exposed end 3 of the metal conductor 1 is larger than the radius (D1/2) of the metal conductor 1. In other words, the relationship is R1<(D1/2)<L1. This lengthens the exposed tip of the metal conductor 1, improving the contact between the tip 1b of the probe needle 10 and the electrode 51 on the inspection device side. As a result, contact problems between the two can be eliminated.

Since the diameter D1 of the metal conductor 1 is in the range of 8 μm to 120 μm as described above, the radius of curvature R1 is less than the actual radius of the metal conductor 1. The lower limit of the radius of curvature R1 is not particularly limited, but can be set to 50% of the radius. In addition, the upper limit of the length L1 in the longitudinal direction Y of the end 3 of the exposed metal conductor 1 is not particularly limited, but can be set to 10 times the radius of the metal conductor 1.

The radius of curvature R1 of the tip 1b can be processed to any desired radius of curvature R1 by grinding or polishing with a grindstone or the like. The length L1 can be set to a predetermined length by controlling the length of the insulating coating 2 that is peeled off, for example, by laser.

(insulating coating)
1 and 2, the insulating coating 2 is provided on the outer periphery of the metal conductor 1 in an area other than at least both ends 3, 3. The portion having the insulating coating 2 is referred to as the body portion 6, and the portion not having the insulating coating 2 is referred to as the end portion 3, with the object to be measured side represented as the tip 1a and the inspection device side represented as the tip 1b.

The material of the insulating coating 2 is not particularly limited, but is preferably composed of one or more resin materials selected from polyurethane, polyester, polyesterimide, polyamideimide, polyimide, and fluororesin. The insulating coating 2 is formed in a single layer or in two or more layers using one or more of the above resin materials. The insulating coating 2 is usually preferably formed on the long metal conductor 1 by a continuous enamel baking method, but may also be formed by other known methods such as electrochemical coating.

The thickness T1 of the insulating coating 2 is within the range of 1 μm to 20 μm. The insulating coating 2 may be a single layer or a laminate of two or more layers (three or four layers are also possible), and is not particularly limited, but it is convenient to incorporate a pigment or dye to make it distinguishable from other probe needles 10. Either pigment or dye may be used, but it is preferable to use a pigment from the viewpoint of not reducing the strength of the insulating coating 2. As the pigment, various pigments that are generally used to identify enameled wires can be used. Such pigments can be incorporated into a resin to make an enamel paint, and the enamel can be baked to form a colored insulating coating 2.

As in the case of the metal conductor 1 described above, the outer diameter D2 of the body portion 6 on which the insulating coating 2 is provided must be small in order to meet the demand for narrower pitches of the electrodes 12 of the object to be measured 11, and is preferably in the range of 10 μm to 200 μm, and more preferably in the range of 13 μm to 180 μm.

(Insulation coating end shape)
The insulating coating 2 has an end 7b on the inspection device side Y2 in the longitudinal direction Y that has a curved shape. Since the end 7b of the insulating coating 2 is curved and not at a right angle, even when the probe needle 10 is inserted from one of the guide holes (21, 31), the end 7b of the insulating coating 2 has no corners, and the periphery of the end of the insulating coating 2 is less likely to get caught.

The relationship between the radius of curvature R2 of the end 7b, the outer diameter D2 of the body 6, the length L2 in the longitudinal direction Y of the curved surface, and the thickness T1 is R1<R2<(D2/2) and L2>T1. The length L2 is calculated as the length from the base point where the thickness T1 of the insulating coating 2 starts to decrease from a constant thickness to the tip of the end 7b. By doing so, as shown in FIG. 4, even if the probe needle 10 inserted into the guide hole 31 of the second support plate 30 on the inspection device side is tilted, the end 7b of the insulating coating 2 will contact the inner surface 32 of the guide hole 31. As a result, even if the inner surface 32 of the guide hole 31 and the end periphery of the insulating coating 2 of the probe needle 10 come into sliding contact with each other during repeated inspections, peeling of the insulating coating 2 can be prevented, and defects such as damage to the inner surface 32 of the guide hole 31 can be prevented.

If the radius of curvature R2 of the end 7b of the insulating coating 2 is smaller than the radius of curvature R1 of the tip 1b of the metal conductor 1, the area where the edge of the end of the insulating coating 2 touches the guide hole 31 becomes smaller, so the pressure at the touching part increases, making it easier to damage the inner surface 32 of the guide hole 31. The curved shape of the end 7b of the insulating coating 2 does not have to be a geometric circular curved shape, and it may be a flattened curved shape such as an ellipse.

Since the thickness T1 of the insulating coating 2 is within the range of 1 μm to 20 μm as described above, the upper limit of the length L2 that is greater than the thickness T1 is not particularly limited, but can be set to 5 times the thickness T1. The radius of curvature R2 of the insulating coating 2 and the length L2 of the end 7b can be processed to any radius of curvature R2 and length L2 by grinding or polishing with a grindstone or the like.

(Probe unit)
2, the probe unit 60 according to the present invention has a support plate 20 arranged on the side of the object to be measured, a support plate 30 arranged on the side of the inspection device, and a probe needle 10 attached to a guide hole 21, 31 provided in each of the at least two support plates 20, 30, and is a probe unit used for inspection by contacting the inner surface of the guide hole of either of the support plates with the probe needle 10 and contacting the tip 1a of the metal conductor 1 constituting the probe needle 10 with an electrode 12 of the object to be measured 11. The probe needle 10 has a body 6 having an insulating coating 2 on the outer periphery of the pin-shaped metal conductor 1, and end portions 3 at both ends of the metal conductor 1 that do not have the insulating coating 2. The characteristic of this probe needle 10 is that in the probe needle 10 which contacts the inner surface 32 of the guide hole 31 in the support plate 30, the metal conductor 1 has a tip 1b which is curved in shape, with a radius of curvature of the curved surface being R1, the outer diameter of the metal conductor 1 being D1, and the length of the end 3 being L1, while the insulating coating 2 has an end 7b in the longitudinal direction Y which is curved in shape, with a radius of curvature of the curved surface being R2, the outer diameter of the body 6 being D2, the length of the curved surface in the longitudinal direction Y being L2, and the thickness being T1, then, for the metal conductor 1, R1<(D1/2)<L1, and for the insulating coating 2, R1<R2<(D2/2) and L2>T1.

Since such a probe unit 60 also has the probe needle 10 according to the present invention, the exposed tip of the metal conductor 1 is longer, and the contact between the tip 1b of the probe needle 10 and the electrode part 51 on the inspection device side is improved. As a result, contact problems between the two can be eliminated. In addition, when the probe needle 10 is inserted into the guide hole from the tip 1b side, the end 7b of the insulating coating 2 has no corners, and the edge of the end of the insulating coating 2 is less likely to get caught. In addition, even if the probe needle 10 inserted into the guide hole 31 of the second support plate 30 on the inspection device side is tilted, the end 7b of the insulating coating 2 contacts the inner surface 32 of the guide hole 31, so even if the inner surface 32 of the guide hole 31 and the edge of the insulating coating 2 of the probe needle 10 come into sliding contact with each other during repeated inspections, peeling of the insulating coating 2 can be prevented, and problems such as damage to the inner surface 32 of the guide hole 31 can be prevented.

The second support plate 30 on the inspection device side has a guide hole 31 with an inner diameter D3 slightly larger than the outer diameter D2 of the body 6. On the other hand, the first support plate 20 on the measured object side has a guide hole 21 with an inner diameter slightly larger than the outer diameter D1 of the metal conductor 1. "Slightly larger" means that it is larger by a small clearance (e.g., 1 to 3 μm). Since the guide hole 21 is smaller than the outer diameter D2 of the body 6, the probe needle 10 does not slip through the guide hole 21, and the end 7a of the insulating coating 2 abuts against the edge around the guide hole. The guide hole 21 guides each probe needle 10 so that the tip 1a of the metal conductor 1 on the measured object side accurately contacts the electrode 12 of the measured object 11.

2, when inspecting the electrical characteristics of the object to be measured 11, the position of the probe unit 60 is controlled so that the probe needle 10 corresponds to the object to be measured 11. The electrical characteristics are inspected by stroking the probe unit 60 up and down and pressing the tip 1a of the probe needle 10 on the object to be measured against the electrode 12 of the object to be measured 11 with a predetermined pressure using the elastic force of the probe needle 10. At this time, the tip 1b of the probe needle 10 on the inspection device side comes into contact with the electrode portion 51 of the lead wire 50, and the electrical signal from the object to be measured 11 is sent to the inspection device (not shown) through the lead wire 50.

The following is a detailed explanation using examples and comparative examples.

[Example 1]
A long rhenium tungsten wire (outer diameter D1: 30 μm) was used as the metal conductor 1. The insulating coating 2 had a single layer structure, was formed using polyester enamel paint, and had a thickness T1 of 4 μm. The long probe needle on which the insulating coating 2 was formed was cut with a fixed length cutter to cut out an insulating coated probe needle having a length of 10 mm, and a predetermined length of both ends of the insulating coated probe needle was laser peeled off to produce the probe needle 10 of Example 1. The outer diameter D2 of the body portion 6 was 38 μm.

In this probe needle 10, the radius of curvature R1 of the tip 1b was processed to 14 μm by grinding with a grindstone, and the length L1 was set to 20 μm by removing the insulating coating 2 at the end 3 with an excimer laser. The radius of curvature R2 and length L2 of the end 7b of the insulating coating 2 were processed to 18 μm radius of curvature R2 and 13 μm length L2 by gradually removing it by irradiating it with an excimer laser with a reduced output. These dimensions are shown in Table 1.

[Examples 2 to 8, Comparative Examples 1 to 3]
In Examples 2 to 8 and Comparative Examples 1 to 3, the respective probe needles 10 were fabricated by processing to have the dimensions shown in Table 1. The materials of the metal conductor 1 and the insulating coating 2 were the same as those in Example 1.

[evaluation]
4 and 5, the probe needle 10 was inserted into the guide hole 31 of the second support plate 30 on the inspection device side, and stroked 350,000 times (stroke length: 0.2 mm) while tilted so that the end 7b of the insulating coating 2 was in sliding contact with the inner surface 32 of the guide hole 31. The evaluation was performed by marking "◯" when the inner surface of the guide hole 31 was not scraped, the insulating coating 2 was not peeled off, and there was no contact failure between the tip 1b of the probe needle 10 and the electrode part 51 on the inspection device side, and marking "X" when scraping was confirmed.

LIST OF SYMBOLS 1 Metal conductor 1a Tip on object under test 1b Tip on inspection device 2 Insulating coating 3 End 4 Plating layer 6 Body 7 End of insulating coating abutting periphery of guide hole 7a End of insulating coating 7b End of insulating coating 10 Probe needle 11 Object under test 12 Electrode 20 First support plate 21 Guide hole 30 Second support plate 31 Guide hole 32 Inner surface 40 Holding plate for lead wire 50 Lead wire 51 Electrode 60 Probe unit D1 Outer diameter of metal conductor D2 Outer diameter of body D3 Inner diameter of guide hole R1 Radius of curvature of tip of metal conductor R2 Radius of curvature of end of insulating coating L1 Longitudinal length of end L2 Longitudinal length of end of insulating coating T1 Thickness of insulating coating

Claims (4)

A probe needle having a body part having an insulating coating on the outer periphery of a pin-shaped metal conductor, and ends at both ends of the metal conductor not having the insulating coating,
The metal conductor has a curved tip shape, the radius of curvature of the curved surface is R1, the outer diameter of the metal conductor is D1, and the length of the end is L1. The insulating coating has a curved end shape in the longitudinal direction, the radius of curvature of the curved surface is R2, the outer diameter of the body is D2, the longitudinal length of the curved end shape of the insulating coating in the longitudinal direction is L2, and the thickness of the insulating coating is T1.
A probe needle, wherein the metal conductor satisfies R1<(D1/2)<L1, and the insulating coating satisfies R1<R2<(D2/2) and L2>T1. The probe needle of claim 1, wherein the outer diameter of the metal conductor is in the range of 8 μm to 180 μm, and the outer diameter of the body is in the range of 10 μm to 200 μm. The probe needle according to claim 1 or 2, wherein the thickness of the insulating coating is in the range of 1 μm to 10 μm. A probe unit for use in testing comprising a support plate arranged on a test subject side, a support plate arranged on a testing device side, and probe needles attached to guide holes provided in at least two of the support plates, the probe needles contacting an inner surface of the guide hole of any one of the support plates and contacting a tip of a metal conductor constituting the probe needle with an electrode of the test subject,
The probe needle has a body portion having an insulating coating on the outer periphery of a pin-shaped metal conductor, and ends at both ends of the metal conductor that do not have the insulating coating,
The metal conductor has a curved tip shape, the radius of curvature of the curved surface is R1, the outer diameter of the metal conductor is D1, and the length of the end is L1,
a probe unit characterized in that, when an end shape of the insulating coating in the longitudinal direction is curved, a radius of curvature of the curved surface is R2, an outer diameter of the body portion is D2, a longitudinal length of the curved end shape of the insulating coating in the longitudinal direction is L2, and a thickness of the insulating coating is T1, the metal conductor satisfies R1<(D1/2)<L1, and the insulating coating satisfies R1<R2<(D2/2) and L2>T1.

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