JPH10270140A - Contact pin and its manufacture and contact method using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a contact pin, its manufacturing method, and a contact method using the pin capable of suppressing abrasion on a contact surface for obtaining an electrical connection through contact with a lead of a package for sealing an integrated circuit. SOLUTION: A contact surface 2 formed by a surface joining outer edge parts 34 and 36 whose surfaces are in parallel with each other is shaped as a surface recessed into the inside of a pin 38. Therefore, the outer edge parts 34 and 36 are deeply cut into the surface of a lead at the time of contact to obtain a strong contact force, and to restrain abrasion of the contact surface 2. In order to obtain such shape, a through hole having a predetermined width is formed around the periphery of the shape of the pin 38 made by etching a metal plate 31 to undergo plating treatment.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a contact pin, a method of manufacturing the same, and a contact method using the same. More particularly, the present invention relates to a socket for connecting an integrated circuit to an external circuit for measuring the integrated circuit. The present invention relates to a contact pin, a method of manufacturing the contact pin, and a contact method using the pin, for obtaining electrical connection by contacting a lead of a package in which the integrated circuit is sealed.

[0002]

2. Description of the Related Art For the purpose of making measurements for inspection of a semiconductor integrated circuit, a large number of contact pins for individually contacting the leads of a package encapsulating the integrated circuit and obtaining electrical connection are available. Proposed.

FIG. 8 is a diagram showing an arrangement of a package having a plurality of leads and a plurality of contact pins provided corresponding to each of the leads. Here, 1 is a contact pin, and the plurality of contact pins 1 are arranged along the X-axis direction in the figure. Each contact pin 1 is configured to have a plane parallel to the X, Y, and Z axes. 2 is a contact surface formed on the end of each contact pin 1 in the Z-axis direction,
While being parallel to the X axis, it is in direct contact with the lead 3 under the mechanical pressure from the lead 3 of the package 4. The lead 3 is usually made of an iron-nickel alloy or a copper alloy. The surface of the lead 3 is plated with tin or solder to facilitate soldering to the printed circuit board. The package 4 seals one end of the lead 3 and the integrated circuit. Reference numeral 5 denotes a socket body, and the bottoms of the plurality of contact pins 1 in the Z-axis direction are fixed. The contact pin 1 has a curved portion 6
Having. On the contact surface 2 there is an end 9.

Here, a relatively strong mechanical pressure is applied from the lead 3 to the contact surface 2 so that the electrical connection between the lead 3 and the pin 1 is good. When measuring a large number of integrated circuits for inspection, the contact surface 2 is worn due to repeated contact with a new lead 3 due to relatively strong pressure. When abrasion occurs, a good contact area having a low electric resistance is reduced, thereby causing an increase in the contact resistance value.
In particular, in a measurement system of an analog circuit, the contact resistance value is incorporated and adjusted as a part of the series resistance value of the measurement system. When the contact resistance value changes in such a measurement system, a problem occurs that a value different from the original measurement value is recognized. In order to avoid such a state, the contact pins 1 are exchanged regularly, and the entire socket including the contact pins 1 is usually exchanged when about 100,000 measurements are performed.

FIG. 9 is a diagram illustrating the shape of the contact pin 1. Generally, the contact pin 1 is manufactured from a metal plate, and the main surface of the metal plate is the main surface 1a of the contact pin 1.
This main surface 1a corresponds to the front view of this figure. The back face with respect to this front view is the facing face 1b. A sectional view along the line AA 'at the end of the contact pin 1 forms the XZ plane at the end in FIG.

FIG. 10 shows a state in which the lead 3 has come into contact with the contact pin 1 from the X-axis direction in FIG. Here, a state in which the distance from the socket 5 to the tip of the contact pin 1 before contact is h is a state where the distance is compressed by Δh after contact. Due to this compression, a stress acts from the contact pin 1 toward the lead 3 with the curved portion 6 as a fulcrum. Due to this stress, the contact surface 2 of the contact pin 1 and the lead 3 make strong contact. Here, the contact surface 2 contacts the lead 3 with the maximum area at the time of contact,
The contact surface 2 may be set so as to have a predetermined angle with respect to the inclination angle of the lead 3. That is, in this case, the above-described angle and mechanical pressure are set so that the contact pin 1 comes into contact with the lead 3 with the maximum area in a state where the contact pin 1 is sunk by Δh. During this sinking process, a strong frictional force is generated between the lead 3 and the end 9 of the contact surface 2.

FIG. 11 shows a contact surface 2 of a conventional contact pin 1.
Is a micrograph showing the image magnified 120 times. This conventional contact pin 1 is obtained by plating a metal piece formed by cutting a metal plate, and a part of the cut surface is used as a contact surface 2. In this cut surface, the cutting is started from the main surface, which is one surface of the metal plate forming the contact pin 1, and is ended at the opposite surface, which is the other surface. A tooth profile formed by cutting remains from the main surface to a central portion that reaches the facing surface, and a torn surface appears from the central portion to the facing surface.

As described above, an iron alloy or a copper alloy is used as a material of the metal plate. In order to stabilize the surface of the metal, a plating process is performed after forming a pin shape by cutting. Specifically, nickel plating for forming a hard film and gold plating for covering the periphery and preventing oxidation are applied. The thickness of this plating is usually about 0.3 μm as a whole, and the thickness of the gold plating portion is equivalent to 7 to 8 in terms of the number of gold lattices.

FIG. 12 shows a step of forming the shape of the pin 1 by cutting, which is a conventional method. Here, 7 is a metal plate, and 8 is a cutting tool. FIG.
(A) to (c) show a state in which the tip of the cutting tool 8 is applied substantially perpendicular to the metal plate 7 and the cutting proceeds. FIG. 12D shows a state where the cutting is completed.

From the surface where the cutting is started, that is, from the surface of the metal plate 7 to the central portion in the thickness direction, a tooth profile formed by pressing the teeth of the tool 8 remains, and from the central portion to the end portion, the metal plate is torn. The cut shape remains, and a protruding portion 7a extending outward from the metal plate 7 is formed at the cut end portion.

[0011]

In such prior art, the contact pin 1 uses the surface cut as described above as the contact surface 2 and the surface is rough. . Further, since almost all of the contact surface 2 comes into contact with the lead 3, a relatively strong frictional force is generated between the lead 3 and the contact surface 2. Therefore, the plating surface applied to the contact surface 2 is polished with a relatively strong force. As the polishing proceeds, the underlying metal material is exposed.

When the end 9 of the contact surface 2 that rubs against the lead 3 is formed by the protruding portion 7a of the metal plate 7, the average of the frictional force generated at the end of the contact pin 1 is obtained. Therefore, it is necessary to strongly press the lead 3 against the contact surface 2 in consideration of the above, and the wear of the plating surface is accelerated.

The present invention has been made in view of such a situation, and (1)
Obtaining the shape and structure of the contact surface that can contact the lead even with relatively weak mechanical pressure and suppress the wear, (2) A method of manufacturing a contact pin having such a shape and structure And (3) to obtain a contact method in which abrasion of the contact surface is suppressed.

[0014]

In order to achieve this object, a contact pin according to the present invention has a main surface and a facing surface which are parallel to each other, and an outer edge portion of the main surface and the facing surface. And a contact surface formed by a surface connecting to the outer edge of the pin, and the contact surface has a concave shape facing the inside of the pin.

According to the contact pin of the first aspect,
In the contact portion, the outer edge of the main surface and the outer edge of the facing surface are parallel, and the contact surface connecting the two outer edges has a concave shape, so that when contacting with another member, the other member and the outer edge When they come into contact with each other, the outer edge portion wedges into other members in a wedge-like manner to obtain a strong contact force. Also,
Since both outer edges are parallel, when the outer edges move by rubbing on the surface of the other member, only a relatively low frictional force is generated as compared with the case where the outer edges rub on the entire surface, and therefore, the external force is applied. The pressure can be reduced. For this reason, it is possible to suppress wear occurring at the outer edge.

According to a second aspect of the present invention, there is provided a contact pin including a metal piece and a metal layer formed on the surface of the metal piece and harder than the metal piece. This claim 2
According to the contact pin described above, it is possible to suppress wear of the outer edge portion formed along the contour of the metal piece.

Further, in the contact pin according to the third aspect, the metal layer is formed on the surface of the metal piece and is formed on the first metal layer which is harder than the metal piece and on the surface of the first metal layer. And a second metal layer having a lower electric resistance than the first metal layer.

According to the contact pin of the third aspect,
Even when the first metal layer is a relatively hard metal and has a high electric resistance instead of a relatively hard metal, by reducing the electric resistance of the second metal layer covering the surface, the abrasion resistance of the outer edge portion is reduced. The electrical resistance of the contact pin can be kept low while securing.

The contact pin according to a fourth aspect is characterized in that arcuate ends are formed at both ends in the length direction of the outer edge. According to the contact pin of the fourth aspect, when the outer edge portion moves by rubbing on the surface of another member,
Since the end, which is the corner of the outer edge, has an arc shape, the frictional force generated at the rubbed portion can be suppressed low.

According to a fifth aspect of the present invention, there is provided a method for manufacturing a contact pin.
Except for the region of the supporting portion for supporting the formed contact pin on the metal plate serving as the base material for manufacturing the pin, the metal plate is directed from the main surface to the opposite surface along the contour of the contact pin. A penetrating step of penetrating with a predetermined width, and a plating step of plating a metal layer harder than the metal plate on a portion having the shape of the pin after the penetrating step are provided.

According to the method of manufacturing a contact pin according to the fifth aspect, the gap between the outer edge of the pin and the remaining metal plate can be set to a predetermined width by the penetrating portion. Then, by using this gap, it is possible to change the thickness of the plating that covers the pin shape when the entire metal plate is plated. Specifically, by adopting electroplating, the action of the gap having the predetermined width promotes the growth of plating at a portion where the electric field intensity is high at the outer edge portions of the pin shapes on both surfaces of the metal plate, In the central part of the thickness of the plate, the circulation of the plating solution can be suppressed and the electric field intensity can be reduced, so that the thickness of the plating in the central part can be made relatively thinner than the outer edge part. In this way, the contact surface connecting the outer edges of the pin shape can be formed in a concave shape. After the plating, the contact pins can be taken out by cutting the support portion.

Further, in the method of manufacturing a contact pin according to claim 6, the plating step includes plating a first metal harder than the metal plate on a surface of the metal plate, and plating the first metal. Plating a second metal having a lower electric resistance than the first metal on the surface of the portion.

According to the contact pin manufacturing method of the sixth aspect, even if the first metal is a relatively hard metal and its electric resistance is high, the second metal covering the surface of the first metal can be used. By reducing the electrical resistance of the metal, the electrical resistance of the contact pin can be kept low while ensuring the outer edge against abrasion.

Further, in the contact method using the contact pin according to claim 7, the contact pin has a main surface and a facing surface which are parallel to each other, and the outer edge of the main surface and the outer edge of the facing surface are connected to each other. A contact surface formed by a connecting surface, the contact surface having a concave shape facing the inside of the pin, and at least a part of the contact surface and the other member after contacting the outer edge with another member. Is brought into contact with.

According to the contact method of the present invention, since the outer edge having a relatively small area comes into contact with another member, the outer edge portion comes into contact with a strong pressure per unit area, and furthermore, the outer edge has a relatively large area. Since at least a part of the contact surface having a contact comes into contact with another member, the contact surface can be contacted with a relatively low pressure per unit area to obtain an electrical connection. For this reason, reliable contact can be obtained, and wear on the contact surface can be suppressed.

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a view showing a shape of a contact pin according to an embodiment of the present invention, and is a cross-sectional view of the contact pin as viewed from a plane corresponding to the XZ plane in FIG. In this contact pin 38, reference numeral 31 denotes a metal plate, which is usually provided with a thickness of about 0.3 mm, and made of an iron nickel alloy or a beryllium copper alloy. A first metal layer 32 is formed on the surface of the metal plate 31, and a second metal layer 32 is further formed on the surface of the first metal layer 32.
Metal layer 33 is formed. A material mainly composed of nickel is used for the first metal layer 32, and the second metal layer 33
Is made of a material mainly composed of gold. The outer edges 34 and 35 of the first and second metal layers 32 and 33 are formed along the outer edges where the main surface of the metal plate 31 and the corresponding side surface are in contact. The outer edges 36 and 37 of the second and third metal layers 32 and 33 are also formed at portions along the outer edge where the facing surface of the metal plate 31 and the corresponding side surface are in contact. Since the metal plate 31 has been subjected to an etching process, which will be described later, the metal plate 31 has a raised shape at the center of the side surface of the plate. j is the height of the outer edges 34 and 36 with reference to the contact surface 2, and K is the total thickness of the metal layer 32 and the metal layer 33.

To form the first metal layer 32, nickel is electroplated so as to cover the main surface, the facing surface, and the side surface of the contact pin 38, and to form the second metal layer 33, Gold is electroplated over the nickel surface. The first and second metal layers 32, 3
A surface connecting the outer edge on the main surface side and the outer edge on the facing side of 3 is formed as a curved surface as the contact surface 2 on the side surface of the contact pin 38.

As described above, the outer edges 34 to 37 of the metal layer
Constitutes a parallel edge formed by a layer of nickel and a layer of gold covering the periphery thereof, and the outer edge 3 of the contact surface 2
4, 36 make contact with the tin or solder layer on the surface of the lead. By adjusting the mechanical pressure required for this contact, the contact area between the contact surface 2 and the surface of the lead can be adjusted.

In the process in which the outer edges 34 and 36 cause friction with the lead, the outer edges 34 and 36 come into contact with each other with a relatively small area, so that the frictional force generated there is small. Can be smaller. Since the pressure is small, abrasion of the contact surface 2 can be suppressed.

FIG. 2 is a front view, a plan view, and a right side view of the vicinity of the contact surface 2 of the contact pin 38. FIG. 1 is a sectional view of the front view taken along line BB ′.
The contact surface 2 has a concave shape having a raised portion at the center.

An end 91 along the length of the outer edge 34,
92 is formed in an arc shape when viewed from the front, and the outer edge 3 is similarly formed.
The ends 93 and 94 of 6 are also formed in an arc shape. By having this arc shape, the lead 3 and the end portions 91 to 9
4 can smoothly come into contact with each other. The radius of this arc shape can be set to any value, but in order to secure the required effective length at the outer edges 34, 36 of the contact surface 2,
Approximately 1 / th of the length t corresponding to the entire length of the outer edge portions 34, 36
A length of 10 is appropriate.

3 to 5 are views showing a method for manufacturing a contact pin according to the present invention. FIG. 3A is a diagram illustrating the shape of the contact pin 38, a support portion 39 that supports the pin 38 on the metal plate 31, and a through hole 40. FIG.
FIG. 3B is a cross-sectional view taken along the line CC ′ in FIG.

Here, the through hole 40 is for separating the contact pin 38 and the supporting portion 39 from the metal plate 31 and is formed along the contour of the contact pin 38. The support part 39 is connected to the metal plate 31 at one end. The width w of the through hole 40 is usually set to a value of 1 to 2 mm.

FIG. 4 shows a plurality of contact pins 3 on a metal plate 31.
8 shows a state in which No. 8 is formed. In this case, the through hole 40 does not need to have a uniform width over the entire periphery of the contact pin 38, and at least in a required portion near the contact surface 2, It is sufficient if a predetermined width w for shaping the shape is secured.
A metal plate 31 having a size of about 20 cm × 40 cm is used. When the area required for forming one contact pin 38 is about 1 square centimeter, this one sheet of metal is used. About 1000 contact pins 38 can be taken out from the plate 31.

FIGS. 5A to 5D are views showing a method of forming the through holes 40, that is, the contact pins 38. FIG. FIG.
4A, reference numeral 41 denotes a resist, which is applied with precision to the positions of the main surface and the facing surface of the metal plate 31 facing each other.
The resist 41 is removed from the portion requiring the through hole 40, and the etching is started at the removed portion. When the metal plate 31 is a beryllium copper alloy, ferric chloride or a hydrogen peroxide solution is used as the etchant.

FIG. 5B shows an intermediate step of the etching. The etching proceeds from the main surface and the facing surface of the metal plate 31 and the end of the resist 41 toward the inside of the metal plate 31.

FIG. 5C shows a state where the etching is completed. In this figure, reference numeral 42 denotes a projection formed at the center of the side surface of the metal plate 31 and the contact pin 38. The height of the projection 42 can be suppressed to about several microns by adjusting the etching time. By performing the etching process in this manner, it is possible to prevent the occurrence of tooth shapes, split shapes, chips, and the like, which cannot be avoided when cutting with a knife as in the related art. Further, even if the outline of the contact pin 38 is complicated, the contact pin 38 can be easily penetrated, and the pin shape in a minute portion can be easily devised.

FIG. 5D shows a state in which the resist layer has been removed. In FIG. 5D, the pin 3
The width w for maintaining the relative position between the metal plate 8 and the metal plate 31 is held by the support 39.

Next, electroplating is performed while the pins 38 and the metal plate 31 after the removal of the resist layer remain connected. In general, when the current efficiency is 100%, the number of metal atoms deposited per unit time on the surface of the metal plate 31 which is the object to be plated is proportional to the current density. The precipitated atoms collectively become crystal nuclei, and gradually form a plating layer. Here, when the current density is low, the generation frequency of crystal nuclei is low, and a small number of crystals grow slowly. Conversely, when the current density is high, the frequency of generation of crystal nuclei is high, crystal growth is accelerated, and many fine crystals are formed.

In the outer edge portions 43 to 46 of the metal plate 31 and the pins 38 in the region of the through hole 40, a plating layer thicker than other portions is formed because an electric field is concentrated in the electroplating process. When a thick plating layer starts to be formed, the shape becomes a projection, and the electric field is further concentrated, thereby promoting the growth of the plating layer. Also, the through hole 40
Compared with the other region, the supply of ions is poor in the region of the through hole 40 due to its shape. For this reason,
The thickness of the plating layer on the side surface where the through hole 40 is formed is further reduced as compared with other portions. For this reason, a specific orientation appears in the growth direction of the plating layer, and a concave shape is formed in the region of the through hole 40.

The metal layers 32 and 33 are formed as described above. In order to obtain the required thickness, the temperature, concentration, pH value of the plating solution and the plating time are generally required. Need to be managed. Here, especially for gold plating for forming the metal layer 33, the degree of plating can be evaluated and managed by comparing the gloss of the pure gold foil and the gloss of the surface of the contact pin.

[0042]

6 and 7 are photomicrographs showing an embodiment of the contact pin of the present invention. FIG. 6 is an enlarged view of the end portion on which the contact surface 2 is formed 120 times, and FIG. 7 is an enlarged view of the contact surface 2 and its periphery 60 times obliquely. is there. Beryllium copper having a hardness of 1/2 is used as the material of the metal plate, the thickness of the contact pin 38 is 0.3 mm, and the radius of the arc forming the ends 91 to 94 of the contact surface 2 is 0.1 mm. The height j from the side surface forming the contact surface 2 to the outer edges 34 and 36 is about 18 microns, the thickness of nickel plating for forming the inner metal layer 32 is about 5 microns, and the metal layer 33 on the front side is formed. The thickness of the gold plating is about 2 microns. With the contact pin having such a configuration, the life for an average of 2 million contacts was obtained.

[0043]

As described above, according to the present invention, there are provided a main surface and a facing surface which are parallel to each other, and a contact surface formed by a surface connecting the outer edge of the main surface and the outer edge of the facing surface. Since the contact surface has a concave shape facing the inside of the pin, the contact surface can strongly contact other members, and the effect of suppressing wear of the contact surface can be obtained.

Further, since the arc-shaped ends are formed at both ends in the length direction of the outer edge, the frictional force generated at the end when the outer edge rubs on the surface of another member and moves. Can be reduced.

Further, except for a region of a support portion for supporting the formed contact pin on a metal plate serving as a base material for manufacturing the pin, the metal plate is arranged along the contour of the contact pin on the main surface. A penetrating step of penetrating with a predetermined width from the opposite side, and after this penetrating step, in a portion forming the shape of the pin, by providing a plating step of plating a metal layer harder than the metal plate, At the time of plating, the growth of the metal layer at the outer edge of the pin is promoted, and as a result, the contact surface formed by the surface connecting the outer edge of the pin surface and the outer edge of the facing surface can be surely formed into a concave shape. .

[Brief description of the drawings]

FIG. 1 is a diagram showing a cross-sectional shape of a contact pin according to an embodiment of the present invention.

FIG. 2 is a diagram showing an outer shape of a contact pin of FIG. 1;

FIG. 3 is a view for explaining a method of manufacturing the contact pin.

FIG. 4 is a diagram for explaining a method of simultaneously manufacturing a plurality of contact pins.

FIG. 5 is a view showing a method of manufacturing the contact pin.

FIG. 6 is a photomicrograph of an example of the contact pin of the present invention.

FIG. 7 is another micrograph of an example of the contact pin of the present invention.

FIG. 8 is a view showing a state where a conventional contact pin and lead are arranged.

FIG. 9 is a view showing an outer shape of the contact pin of FIG. 8;

FIG. 10 is a diagram showing a contact state between a contact pin and a lead of FIG. 8;

FIG. 11 is a micrograph of a contact surface of a conventional contact pin.

FIG. 12 is a view showing a step of forming a conventional contact pin by cutting.

[Explanation of symbols]

 2 Contact Surface 3 Lead 4 Package 31 Metal Plate 32 Metal Layer 33 Metal Layer 34 Outer Edge 35 Outer Edge 36 Outer Edge 37 Outer Edge 38 Contact Pin 39 Support Portion 40 Through Hole

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Kenichi Miyakoshi, Inventor 1-1, Yukicho, Takatsuki-shi, Osaka Matsushita Electronics Co., Ltd. (72) Inventor Sueo Asahina 1-1, Yukicho, Takatsuki-shi, Osaka Matsushita Electronics (72) Inventor Yoshinori Kojima 1-1, Yukicho, Takatsuki-shi, Osaka Matsushita Electronics Co., Ltd.

Claims (7)

[Claims] 1. A contact pin for obtaining an electrical connection by contacting another member, comprising a main surface and a facing surface parallel to each other, and an outer edge of said main surface and an outer edge of said facing surface. A contact surface formed by a surface connecting the contact pins, and the contact surface has a concave shape facing the inside of the pin. 2. The contact pin according to claim 1, comprising: a metal piece; and a metal layer formed on a surface of the metal piece and harder than the metal piece. 3. A first metal layer formed on the surface of the metal piece and being harder than the metal piece, and a metal layer formed on the surface of the first metal layer and being harder than the first metal layer. 3. A second metal layer having a low electric resistance.
The contact pin as described. 4. The contact pin according to claim 1, wherein arc-shaped ends are formed at both ends in the length direction of the outer edge. 5. A method for manufacturing a contact pin for obtaining electrical connection by contacting another member, wherein the formed contact pin is supported on a metal plate serving as a base material for manufacturing the pin. Excluding the area of the support portion for exposing the metal plate along the contour of the contact pin from the main surface to the opposite surface with a predetermined width, and after the penetrating step, the shape of the pin A plating step of plating a metal layer harder than the metal plate on a portion forming the contact pin. 6. The plating step includes plating a first metal, which is harder than the metal plate, on a surface of the metal plate;
6. A method of manufacturing a contact pin according to claim 5, further comprising: plating a second metal having lower electric resistance than the first metal on a surface of the metal plating portion. 7. A contact method using a contact pin for contacting another member to obtain an electrical connection, wherein the contact pin has a main surface and a facing surface parallel to each other, and A contact surface formed by a surface connecting the outer edge of the surface and the outer edge of the facing surface, the contact surface having a concave shape facing the inside of the pin, and after contacting the outer edge with another member. A contact method using a contact pin, wherein at least a part of the contact surface is brought into contact with the other member.