JP2005268090A - Contact pin and socket for electrical component - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a contact pin and a socket for electrical components wherein pasting to the electrical components terminal is suppressed and a resistance value can be made small even after a burn-in test. <P>SOLUTION: In the contact pin 20 which is arranged and installed at an IC socket 11 and which is contacted with a solder ball 13b of an IC package 13, this is the contact pin 20 in which a gold nickel alloy plating 22f is applied to a surface of a contact part 22c to be contacted with at least the solder ball 13b. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a contact pin disposed in an electrical component socket for detachably holding an electrical component such as a semiconductor device (hereinafter referred to as an “IC package”) and contacting a terminal of the electrical component, and the contact. The present invention relates to an electrical component socket having pins.

  As this kind of conventional thing, there exists a thing as described in patent document 1, for example. That is, Patent Document 1 discloses an IC socket in which a conductive film made of, for example, rhodium (Rh) is formed on a terminal end surface of a terminal made of, for example, beryllium copper, which comes into contact with an IC or an LCD.

According to this, Sn, which is a coating component of the IC lead, and Pb in the solder adhere to the terminal end surface of the IC socket, and these are oxidized and converted into an oxide film, whereby the contact resistance between the IC lead and the terminal end surface is reduced. It is described that the terminal end face can be prevented from increasing and the terminal end face is always kept in a state close to the initial state.
Japanese Patent Laid-Open No. 5-304229

  However, such a conventional apparatus has a problem that although the predetermined effect can be obtained as described above, the electrical resistance value increases as the number of repetitions of the burn-in test increases.

  Therefore, the present invention provides a contact pin and an electrical component socket in which no solder adheres to the contact portion of the contact pin even after the burn-in test, the resistance value is suppressed from increasing, and sticking to the electrical component terminal is suppressed. The issue is to provide.

  In order to solve such a problem, the invention according to claim 1 is provided on a contact pin that is disposed in an electrical component socket and contacts a terminal of the electrical component, at least on a surface of the contact portion that contacts the terminal. The contact pin is plated with gold-nickel alloy.

  According to a second aspect of the present invention, in addition to the structure of the first aspect, the contact portion is nickel-plated on a copper alloy body, and gold-nickel alloy plating is performed on the nickel plating. It is characterized by being formed.

  In addition to the structure of Claim 1 or 2, the invention of Claim 3 is the 1st plunger which has the said contact part, The 2nd plunger contacted with a wiring board, This 1st plunger and 2nd plunger And a coil spring interposed therebetween.

  According to a fourth aspect of the present invention, in addition to the configuration according to any one of the first to third aspects, the terminal is a solder ball, and the contact portion is in contact with the solder ball. It is characterized by.

  According to a fifth aspect of the present invention, there is provided an electrical component socket having a socket body in which an electrical component is accommodated and the contact pin according to any one of claims 1 to 4 disposed in the socket body. It is characterized by that.

  According to the invention described in each claim, even when a burn-in test of an electrical component is performed, it is possible to prevent the electrical component from being taken out from the socket for the electrical component by suppressing welding between the electrical component terminal and the contact pin. In addition, the transfer of solder to the contact pins can be suppressed, the resistance value can be reduced, and the contact stability can be ensured.

  Embodiments of the present invention will be described below.

  1 to 3 show an embodiment of the present invention.

  First, the configuration will be described. Reference numeral 11 in the figure denotes a surface mount IC socket as an “electrical component socket”. The IC socket 11 is used for performing a performance test of the IC package 13 as an “electrical component”. The IC package 13 and the wiring board P on the IC testing apparatus side are electrically connected.

  The IC package 13 is a so-called BGA (Ball Grid Array) type package, and a large number of solder balls 13b as “terminals” protrude downward from the lower surface of the rectangular plate-shaped package body 13a (FIG. 1). reference).

  On the other hand, the IC socket 11 has a lower plate 16 and an upper plate 18 in which the socket body 15 has insulation properties, and a plurality of contact pins 20 are disposed on the socket body 15.

  The lower plate 16 and the upper plate 18 are respectively formed with a lower through hole 16a and an upper through hole 18a through which the contact pins 20 penetrate at the same pitch.

  Further, the upper plate 18 has an upper plate body 18b in which an upper through hole 18a is formed, and a guide portion 18c for guiding the peripheral edge portion of each IC package 13. Further, the upper plate body 18b is provided with a sheeting portion 18d on which the IC package 13 is placed in contact.

  On the other hand, the contact pins 20 are each formed of a conductive material and have a first plunger 22, a second plunger 24, a cylinder body 25, and a coil spring 26.

  As shown in FIGS. 1 and 2, the first plunger 22 is formed with a stopper portion 22a and a rod-like portion 22b. A contact portion 22c formed at the upper end of the rod-like portion 22b is brought into contact with the solder ball 13b. It has become so.

  As shown in FIG. 3, the first plunger 22 is provided with a nickel plating 22e on a plunger main body 22d, which is a “main body” of a copper alloy. Further, a gold nickel alloy (Au -Ni) It is formed by plating 22f. The gold-nickel alloy plating 22f has a thickness of about 0.3 to 3 μm and includes about 0.1 to 5% of nickel here.

  On the other hand, the cylindrical body 25 has a cylindrical shape, the upper and lower ends thereof are not crimped, is inserted into the upper through hole 18a of the upper plate 18 so as to be movable up and down, and the upper opening peripheral portion is a stopper portion of the first plunger 22 It is abutted against the lower surface of 22a.

  Further, as shown in FIGS. 1 and 2, etc., the second plunger 24 is provided with a rod-like portion 24b having a diameter smaller than that of the stopper portion 24a and projecting downward from the short cylindrical stopper portion 24a. The lower end portion of the rod-shaped portion 24b is brought into contact with the wiring board P. In addition, a shaft portion 24c having a diameter smaller than that of the stopper portion 24a is projected from the stopper portion 24a upward to the second plunger 24, and the shaft portion 24c is slidably inserted into the cylindrical body 25. Has been.

  The second plunger 24 is inserted into the lower through hole 16a of the lower plate 16 so as to be movable up and down. The second plunger 24 inserted into the lower through-hole 16a from above is prevented from falling downward by the lower surface of the stopper portion 24a coming into contact with the stepped portion 16b of the lower through-hole 16a. It has become so.

  The lower portion of the rod-like portion 24 b of the second plunger 24 protrudes downward from the lower surface of the lower plate 16.

  Further, as shown in FIG. 2, the coil spring 26 is interposed between the upper surface of the stopper portion 24 a of the second plunger 24 and the peripheral edge of the lower opening of the cylindrical body 25. The second plunger 24 and the second plunger 24 are urged away from each other.

  Then, as shown in FIG. 1, the lower plate 16 and the upper plate 18 are positioned by a reference pin 27 and fixed with bolts and nuts (not shown), so that the contact pin 20 is assembled between them. It is.

  In such a case, when testing the IC package 12, as shown in FIGS. 1 and 2, the IC socket 11 is fixed on the circuit board P, and the IC package 12 is mounted on the upper plate 18. In the state where the external force from the pressing member (not shown) is not applied, the interval of the pressing amount L is open.

  From this state, when the IC package 12 is pressed downward by the pressing member, the first plunger 22 and the cylindrical body 25 are in a state where the solder ball 13b of the IC package 13 is in contact with the contact portion 22c of the contact pin 20. The coil spring 26 is lowered against the urging force. Then, when the IC package 13 is lowered by a predetermined amount L, the IC package 13 comes into contact with the seating portion 18 d of the upper plate 18. Thereby, a desired contact pressure is obtained between the solder ball 13b and the contact portion 22c.

  In this state, the burn-in test of the IC package 13 is performed. In this case, since the gold-nickel alloy plating 22f is applied to the contact portion 22c of the first plunger 22, the IC package 13 is suppressed by suppressing the welding between the solder ball 13b and the contact portion 22c of the first plunger 22. Can be prevented from being removed from the IC socket 11, solder can be prevented from being transferred to the contact pins 20, the resistance value can be reduced, and contact stability can be ensured.

A test for peeling between the contact pin 20 and the solder ball 13b according to the example of the present invention was conducted, and the following results were obtained. In this test, 228 contact pins 20 were provided, and the contact area between each contact pin 20 and the solder ball 13b was about 0.05 mm ² . In this contact state, after heat resistance at 150 ° C. for 48 hours, it was tested whether it could be peeled off with a load of 400 g. As a result, in this example, the contact pin 20 was applied with the gold-nickel alloy plating 22f, so that the contact pin 20 and the solder ball 13b were not attached and could be peeled off.

  The resistance value between the contact pin 20 and the solder ball 13b according to the example of the present invention was tested, and the following results were obtained. In this test, the contact pin 20 and the solder ball 13b are brought into contact with each other at a high temperature of 150 ° C., and after the heat resistance for a predetermined time, the new IC package 13 is accommodated and the resistance value is measured. As shown in FIG. 4, when this result is observed, it can be seen that the resistance value is stable in the vicinity of 0.5Ω.

Comparative example

  In the comparative example, a contact pin subjected to rhodium plating was used instead of the gold-nickel alloy plating 22f of the above example. As a result of performing a test using the contact pins under the same conditions as in the above example, a result in which the resistance values varied greatly was obtained as shown in FIG.

  Furthermore, instead of the gold-nickel alloy plating 22f of the above-described embodiment, a contact pin on which nickel palladium (Ni-Pd) plating was applied was used. Using such a contact pin, the same peeling test as in the above example was performed. As a result, the solder ball stuck to the contact pin and could not be peeled off.

  Therefore, in these comparative examples, a result completely different from that of the present invention is obtained. If the number of burn-in tests is increased, the difference becomes clearer, and the durability of the IC socket of the present invention becomes extremely high.

  The present invention is not limited to the above-described embodiment, and the contact pin structure or the like may be other, and if the gold-nickel alloy plating is provided at least on the surface of the contact portion, the whole May be provided. In the above embodiment, the present invention is applied to the IC socket 11 as the “electrical component socket”. However, the present invention is not limited to this and can be applied to other devices. Furthermore, the socket for electric parts of the present invention can be applied to a so-called clamshell type IC socket having a cover for pressing an IC package, a so-called open top type IC socket, and the like.

It is sectional drawing of the IC socket for BGA which concerns on embodiment of this invention. It is an expanded sectional view of the contact pin arrangement | positioning part of FIG. 1 which concerns on the embodiment. It is an expanded sectional view showing the contact part of the 1st plunger concerning the embodiment. It is a graph which shows the test regarding the resistance value of the Example of this invention. It is a graph which shows the test regarding the resistance value of a comparative example.

Explanation of symbols

11 IC socket (socket for electrical parts)
13 IC package (electric parts)
13a Package body
13b Solder ball (terminal)
15 Socket body
20 Contact pin
22 First plunger
22a Stopper section
22c Contact area
22d Plunger body (main body)
22e nickel plating
22f Gold-nickel alloy plating
24 Second plunger
25 cylinder
26 Coil spring

Claims (5)

In the contact pin that is arranged in the socket for the electrical component and contacts the terminal of the electrical component,
A contact pin, wherein at least the surface of the contact portion that contacts the terminal is plated with a gold-nickel alloy. 2. The contact pin according to claim 1, wherein the contact portion is formed by applying nickel plating on a copper alloy main body and applying gold-nickel alloy plating on the nickel plating. 3. The first plunger having the contact portion, the second plunger in contact with the wiring board, and a coil spring interposed between the first plunger and the second plunger are provided. Contact pin described. The contact pin according to claim 1, wherein the terminal is a solder ball, and the contact portion is in contact with the solder ball. 5. A socket for electrical parts, comprising: a socket body in which electrical parts are accommodated; and the contact pins according to claim 1 disposed on the socket body.

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