JP2008078032A - Connecting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a connecting device capable of restraining occurrence of an intermetallic compound at the time when a protruded electrode containing tin is pressure-contacted at an elastic arm, in the connecting device in contact with the protruded electrode of an electronic component such as an IC package. <P>SOLUTION: A connecting part formed by sheet metal working or a plating process has a spiral-shaped elastic arm 22. The elastic arm 22 has a coating layer 33 formed on the surface of a core part 30 equipped with a conductive layer 31 and an elastic layer 32, and the coating layer 33 is formed of a platinum-family metal layer, preferably, of plated palladium. When the protruded electrode 42 containing tin provided at the electronic component comes in contact with the coating layer 33, metal diffusion is hardly generated at the contact part, and an intermetallic compound is restrained from being generated and deposited on the contact part. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a connection device in which an electrode provided on an electronic component such as an IC package is installed, and more particularly to a connection device suitable for repeatedly contacting an electrode formed of an alloy containing tin.

  Patent Document 1 below discloses a connection device including a plurality of spiral elastic arms. A plurality of spherical protruding electrodes are provided on the bottom surface of an electronic component such as an IC package, and each protruding electrode is elastically pressed by an elastic arm, and the protruding electrode and the elastic arm are individually connected in a one-to-one relationship. The

The spiral elastic arm described in Patent Document 1 has a three-dimensional shape that protrudes toward the electronic component, and when the electronic component is installed in the connection device, the elastic arm is pressed by the protruding electrode so as to be crushed. The elastic arm is elastically pressed against the protruding electrode by the elastic restoring force at this time.
JP 20042344872

  A spiral elastic arm as described in Patent Document 1 is formed of a conductive material such as copper. Furthermore, in order to reduce the contact resistance between the elastic arm and the protruding electrode, it is generally employed to form a gold layer on the outermost surface of the elastic arm by plating or the like.

  However, since the gold layer formed on the surface of the elastic arm is difficult to oxidize, its surface energy is maintained high. Therefore, when the protruding electrode formed of an alloy containing tin is pressed against the elastic arm, gold diffuses into the protruding electrode, and an intermetallic compound of gold and tin is easily generated. In particular, when the ambient temperature is 100 ° C. or higher or 150 ° C. or higher with the protruding electrode in contact with the elastic arm, the formation of an intermetallic compound is promoted. For example, when the solder containing tin and the contact are in contact with each other and 300 hours have passed in an environment of 150 ° C., the thickness of the intermetallic compound becomes about 50 μm.

  Therefore, for example, the connection device having the elastic arm is used in an inspection device for electronic components such as ICs, and electronic components provided with protruding electrodes containing tin are repeatedly mounted, and further to each electronic component When the heating inspection is performed, the intermetallic compound and a tin alloy connected to the compound are easily deposited on the surface of the elastic arm. When the intermetallic compound and the tin alloy are oxidized, the resistance of the surface of the elastic arm is increased, and the function as a contact is greatly reduced.

  In addition, since the intermetallic compound of tin and gold is hard, the protruding electrode may be damaged by the intermetallic compound deposited on the elastic arm.

  The present invention solves the above-described conventional problems, and even when an electrode containing tin repeatedly contacts, an intermetallic compound does not easily deposit on the contact, and the contact resistance on the surface of the contact can be reduced. The object is to provide a device.

The present invention provides a connection device in which an electronic component having a plurality of electrodes is installed at the bottom.
A plurality of connection portions to which the electrodes formed of an alloy containing tin are connected are provided, and each connection portion is provided with a conductive elastic arm that is press-contacted with elasticity to the electrodes. And
The elastic arm has a conductive core and a coating layer that covers the surface of the core and reduces the contact resistance with the electrode, and the coating layer is formed of a platinum group metal layer. It is characterized by being.

  In the present invention, since the coating layer provided on the surface of the elastic arm is a platinum group metal layer, the contact resistance with the electrode is small. In addition, when an electrode formed of an alloy containing tin touches the elastic arm, the platinum group metal layer hardly diffuses into the electrode, and an intermetallic compound is hardly formed between the surface of the elastic arm and the electrode. .

  In the present invention, the thickness of the platinum group metal layer is 0.1 μm or more and 2 μm or less. More preferably, it is 0.5 μm or less. If the thickness of the platinum group metal layer is within the above range, the platinum group metal layer can sufficiently exhibit the function of reducing the contact resistance with the electrode.

  In the present invention, a gold layer having a thickness of 0.06 μm or less may be formed on the surface of the platinum group metal layer.

  By forming a gold layer on the outermost surface of the elastic arm, the contact resistance with the electrode can be further reduced. In addition, when the thickness of the gold layer is in the above range, gold diffuses into the electrode, but the amount of tin-gold intermetallic compound formed by the diffusion becomes small, and it can be deposited as much as before. Absent.

  In the present invention, the core is formed of at least one of copper or a copper alloy and nickel or a nickel alloy.

  In addition, the present invention is effective in the case where the connection portion is for inspection in which the electronic component having the electrode is repeatedly attached and detached. In this case, it is effective for the case where the temperature is raised in a state where the electronic component is mounted and the internal circuit of the electronic component is inspected.

  When the connection device of the present invention is used for inspection, even if an electrode formed of an alloy containing tin repeatedly contacts the elastic arm, it can prevent the intermetallic compound from being deposited on the elastic arm. .

  In the present invention, preferably, the platinum group metal layer is a palladium plating layer, which can be an electroless plating layer. When palladium is used, a thin coating layer can be efficiently formed on the surface of the elastic arm.

  The connection device of the present invention has a low contact resistance with an electrode, and when an electrode made of an alloy containing tin is repeatedly contacted, an interelectrode compound is hardly deposited between the surface of the elastic arm and the electrode. Become. Therefore, the life of the connecting portion can be extended.

  1 is a partial cross-sectional view of a connection device according to an embodiment of the present invention, FIG. 2 is an enlarged cross-sectional view of a connection portion, and FIG. 3 is a plan view of the connection portion. FIG. 4 is an enlarged cross-sectional view showing a contact state between the elastic arm of the connecting portion and the protruding electrode.

  A connection device 1 shown in FIG. 1 has a base 10. The planar shape of the base 10 is a quadrangular shape, and side walls 10 a that rise almost vertically are formed on each of the four sides of the base 10. A region surrounded by the four side wall portions 10 a is a concave portion, and the upper surface of the bottom portion 10 b is the support surface 12. A connection sheet 15 is installed on the support surface 12. The connection sheet 15 is provided with a plurality of connection portions 20 on the surface of the flexible base sheet 16.

  As shown in FIG. 2, a large number of through holes 16a are formed in the base sheet 16, and a conductive layer 17 is formed on the inner peripheral surface of each through hole 16a by means such as plating. A front-side connection land 17 a that conducts to the conductive layer 17 is formed on the surface of the base material sheet 16, and a back-side connection land 17 b that conducts to the conductive layer 17 is formed on the back surface of the base material sheet 16. Yes.

  The connection portion 20 is formed by punching a thin conductive metal plate and further plated, and each connection portion 20 is joined to the surface of the connection land 17a with a conductive adhesive or the like. Alternatively, the connecting portion 20 is formed by a plating process using a conductive material such as copper or nickel. For example, a plurality of connection portions 20 are formed in a plating process on the surface of a sheet separate from the base material sheet 16, and the sheets are superimposed on the base material sheet 16, and each connection portion 20 is made of a conductive adhesive. Etc. to join the connection land 17a.

  After each connection part 20 is installed in the base material sheet 16, an external force is given and it is formed in a three-dimensional shape. At this time, the internal residual stress is removed by the heat treatment, and the connecting portion 20 can exhibit an elastic force in a three-dimensional shape.

  As shown in FIG. 2, bump electrodes 18 made of a conductive material that are individually connected to the connection lands 17 b are formed on the back surface side of the base material sheet 16. As shown in FIG. 1, when the connection sheet 15 is installed on the support surface 12 that is the surface of the bottom portion 10 b of the base 10, the bump electrode 18 is connected to the conductive portion provided on the support surface 12. .

  The arrangement pitch of the connecting portions 20 on the support surface 12 is, for example, 2 mm or less, or 1 mm or less. The maximum external dimension of the connecting portion 20 is also 2 mm or less, or 1 mm or less.

  As shown in FIG. 2 and FIG. 3, the connection portion 20 is formed with a support portion 21 and an elastic arm 22 integrally and continuously. The elastic arm 22 is formed in a spiral shape, and a base portion 22 a that is a winding start end of the elastic arm 22 is integrated with the support portion 21. The distal end portion 22b, which is the winding end of the elastic arm 22, is located at the center of the spiral. As shown in FIG. 2, the support portion 21 constituting the connection portion 20 is connected to the connection land 17 a, and the elastic arm 22 is three-dimensionally molded so that the tip end portion 22 b is separated from the support surface 12.

  As shown in a sectional view in FIG. 4, the elastic arm 22 includes a core portion 30 and a covering layer 33 that covers the entire circumference of the surface of the core portion 30. The core portion 30 is formed by covering the entire periphery of the conductive layer 31 with an elastic layer 32. The conductive layer 31 is a single layer of copper or an alloy containing copper. As the copper alloy, a Corson alloy having Cu, Si, Ni having high electric conductivity and high mechanical strength is preferably used. The Corson alloy is, for example, Cu—Ni—Si—Mg, Cu 96.2 mass%, Ni 3.0 mass%, Si 0.65 mass%, and Mg 0.15 mass%. The

  The elastic layer 32 is a metal material that is electrically conductive and exhibits high mechanical strength and high flexural modulus, and is an Ni layer or an alloy layer containing Ni. As the Ni alloy, a Ni—X alloy (where X is one or more of P, W, Mn, Ti, and Be) is used. The elastic layer 32 is formed by performing electroplating or electroless plating around the conductive layer 31. The elastic layer 32 is preferably a Ni-P alloy formed by electroless plating. In the Ni—P alloy, by setting the concentration of phosphorus (P) to 10 at% or more and 30 at% or less, at least a part becomes amorphous, and a high elastic modulus and high tensile strength can be obtained. Alternatively, the elastic layer 32 is formed of a Ni—W alloy. Also in this case, by setting the concentration of tungsten (W) to 10 at% or more and 30 at% or less, at least a part becomes amorphous, and a high elastic modulus and high tensile strength can be obtained.

  In FIG. 4, the cross-sectional area of the elastic layer 32 is preferably 20% or more and 80% or less of the cross-sectional area of the core part 30. Within the above range, the core 30 can exhibit both functions of conductivity and springiness. In the cross-sectional view of FIG. 4, the thickness dimension and the width dimension of the core part 30 are both 1 μm or more and 100 μm or less.

  The covering layer 33 reduces contact resistance with the protruding electrode of the electronic component, and is formed of a metal material having a specific resistance lower than that of the conductive material constituting the core portion 30. In this embodiment, the coating layer 33 is a platinum group metal layer. That is, the coating layer 33 is any one of Pd (palladium), Pt (platinum), Ir (iridium), Ru (ruthenium), Rh (rhodium), and Os (osmium). When the covering layer 33 is formed of these platinum group metal layers, it can be formed by an electroplating process. However, if the coating layer 33 is formed of Pd, it can be formed by electroless plating, and the thin coating layer 33 can be formed efficiently and at low cost.

  The covering layer 33 is formed so as to cover the entire periphery of the core portion 30. FIG. 5 is an enlarged view of the cross section of the elastic arm 22 shown in FIG. The film thickness t1 of the coating layer 33 is not less than 0.1 μm and not more than 2 μm, preferably not more than 0.5 μm. Within this range, the contact resistance with the protruding electrode of the electronic component can be reduced, and the structure can be configured at low cost. That is, the coating layer 33 is for reducing the contact resistance of the surface, and the film thickness of the coating layer 33 is 1/10 or less, and further 1/100 or less with respect to the film thickness of the elastic arm.

  As shown in FIG. 2, an electronic component 40 is installed in the connection device 1. The electronic component 40 is an IC package or the like, and various electronic elements such as an IC bare chip are sealed in the main body 41. A plurality of protruding electrodes 42 are provided on the bottom surface 41 a of the main body 41, and each protruding electrode 42 is electrically connected to a circuit in the main body 41. In the electronic component 40 of this embodiment, the protruding electrode 42 has a spherical shape. The protruding electrode 42 may have a truncated cone shape or the like.

  The protruding electrode 42 is made of a conductive alloy containing tin. That is, it is formed of solder containing no lead, and is a tin / bismuth alloy or a tin / silver alloy.

  The connection device 1 according to the embodiment is for inspecting an electronic component 40, and as shown in FIG. 1, an electronic component 40 that is an object to be inspected is mounted in a recess of the base 10. At this time, the electronic component 40 is positioned so that the individual protruding electrodes 42 provided on the bottom surface 41 a are installed on the connecting portion 20. A pressing lid (not shown) is provided on the base 10. When the lid is placed on the base 10, the electronic component 40 is pressed in the direction of arrow F by the lid. With this pressing force, each protruding electrode 42 is pressed against the elastic arm 22, the three-dimensional elastic arm 22 is crushed, and the protruding electrode 42 and the elastic arm 22 are individually connected.

  When the connection device 1 is used for so-called burn-in inspection, a current is applied to the protruding electrode 42 from the external inspection circuit through the connection portion 20 in a state where the ambient temperature is set to about 150 ° C. Then, it is inspected whether the circuit in the main body 41 of the electronic component 40 is disconnected. Alternatively, a predetermined signal is given from the connection portion 20 to the protruding electrode 42, and an operation test of the circuit in the main body portion 41 is performed.

  The electronic component 40 that has been inspected is taken out from the connection device 1, the electronic component 40 to be inspected next is installed in the connection device 1, and the inspection is performed in the same manner. This inspection is repeated. For this reason, the protruding electrodes 42 of new electronic components 40 come in contact with the elastic arms 22 of the connecting portion 20 one after another.

  As shown in FIG. 4, the elastic arm 22 has a coating layer 33 formed on the surface of the core portion 30 made of a conductive metal, and this coating layer 33 is a platinum group metal layer typified by Pd. It is. When the protruding electrode 42 containing tin is pressed against the covering layer 33 formed of the platinum group metal layer, the platinum group metal is difficult to diffuse into the protruding electrode 42, and the contact portion between the covering layer 33 and the protruding electrode 42. In addition, an intermetallic compound of a platinum group metal and tin is hardly generated.

  Whether or not the metal on the surface of the elastic arm 22 diffuses into the protruding electrode 42 to generate an intermetallic compound mainly depends on the following two conditions.

  One condition is the surface energy of the metal covering the elastic arm 22. When the surface of the elastic arm 22 is a gold layer, the surface energy is high because gold is difficult to oxidize. Therefore, when the protruding electrode 42 containing tin contacts the gold layer, the surface energy causes the gold to become tin. As a result, the gold diffuses into the protruding electrode 42. On the other hand, a platinum group metal typified by Pd has a stable surface energy because an extremely thin oxide film is formed on the surface, and Pd or the like is difficult to diffuse into the protruding electrode 42. Moreover, since the oxide film is extremely thin and does not hinder the passage of current due to the tunnel effect, the surface resistance of the elastic arm 22 does not decrease.

  The next condition is the hardness of the surface of the elastic arm 22. Formation of the intermetallic compound when the elastic arm 22 and the protruding electrode 42 are in contact is thermal diffusion of the metal, and is proportional to both the temperature and the contact area of both members. If the surface of the elastic arm 22 is a gold layer, since the surface hardness is low, the contact area with the protruding electrode 42 is widened, and metal thermal diffusion is likely to occur, and an intermetallic compound of tin and gold is formed. Produced and deposited easily. On the other hand, the platinum group metal layer has high hardness, for example, Pd has a Vickers hardness of about 440 to 550 Hv, and Ru has a Vickers hardness of about 650 to 700 Hv. These are sufficiently higher than AuCo (about 160 Hv), AuNi (about 170 to 300 Hv), and AuIn (about 210 Hv), which are alloys containing gold. Therefore, when the coating layer 33 on the surface of the elastic arm 22 is a platinum group metal layer, the surface hardness is high, so that the contact area when the protruding electrode 42 is pressed does not increase, and thus the platinum group metal is not exposed to the protruding electrode. Difficult to diffuse into 42 and intermetallic compounds are less likely to be generated between the elastic arm and the protruding electrode.

  When the covering layer 33 is a platinum group metal layer, unlike the gold layer, an intermetallic compound is hardly generated. Therefore, the contact resistance on the surface of the elastic arm 22 can always be kept low, and damage to the protruding electrode 43 is also reduced. In addition, the intermetallic compound is less likely to damage the protruding electrode 42.

  FIG. 6 shows a modification of the connection device. FIG. 6 shows an enlarged part of a cross section of the elastic arm 22A of the modified example. In this elastic arm 22A, the coating layer 34 on the surface of the elastic layer 32 which is a core part has a two-layer structure. A platinum group metal layer 34a such as Pd is formed on the surface of the elastic arm 22A with the same thickness t1 as shown in FIG. 5, and a gold layer 34b is further formed on the surface. The gold layer 34b is sufficiently thinner than the film thickness of the platinum group metal layer 34a, and the thickness t2 thereof is 0.06 μm or less.

  Since the gold layer 34b having the thickness t2 is very thin and the platinum group metal layer 34a having a high hardness is formed below the gold layer 34b, the contact area with the protruding electrode 42 is reduced, and the metal between tin and gold is reduced. Compounds are less likely to be produced. Further, since the gold layer 34b is very thin, even if an intermetallic compound is generated, the amount thereof is small, and the intermetallic compound does not damage the protruding electrode 42.

  FIG. 7 shows the second embodiment of the present invention and is an enlarged sectional view of the elastic arm 22B. The elastic arm 22B has a core portion made of only Ni or Ni alloy, and is made of, for example, an NI-P amorphous alloy. And the coating layer 33 shown in FIG. 5 or the coating layer 34 shown in FIG. 6 is formed in the outer peripheral surface. Since the elastic arm 22B is mainly composed of Ni or Ni alloy, the overall rigidity and bending elastic modulus are high. Moreover, the contact resistance of the surface is lowered.

The fragmentary sectional view of the connecting device of an embodiment of the invention, Partial enlarged cross-sectional view of the connection portion of the connection device, An enlarged plan view enlarging the plane of the connection part, An enlarged sectional view showing a contact portion between the elastic arm and the protruding electrode, An enlarged sectional view showing a covering layer of an elastic arm, An enlarged sectional view showing a modification of the coating layer of the elastic arm, The expanded sectional view which shows the coating layer of the 2nd Embodiment of this invention,

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Connection apparatus 10 Base 12 Support surface 15 Connection sheet 16 Base material sheet 20 Connection part 21 Support part 22 Elastic arm 30 Core part 31 Conductive layer 32 Elastic layer 33 Cover layer 34 Cover layer 34a Platinum group metal layer 34b Gold layer 40 Electronic component 42 Projecting electrode

Claims (7)

In a connection device in which an electronic component having a plurality of electrodes is installed at the bottom,
A plurality of connection portions to which the electrodes formed of an alloy containing tin are connected are provided, and each connection portion is provided with a conductive elastic arm that is press-contacted with elasticity to the electrodes. And
The elastic arm has a conductive core and a coating layer that covers the surface of the core and reduces the contact resistance with the electrode, and the coating layer is formed of a platinum group metal layer. A connection device characterized by comprising:   The connection device according to claim 1, wherein a film thickness of the platinum group metal layer is 0.1 μm or more and 2 μm or less.   The connection device according to claim 1, wherein a gold layer having a thickness of 0.06 μm or less is formed on a surface of the platinum group metal layer.   The connection device according to any one of claims 1 to 3, wherein the core portion is formed of at least one of copper or a copper alloy and nickel or a nickel alloy.   The connection device according to any one of claims 1 to 4, wherein the connection device is for inspection in which mounting and dismounting of the electronic component having the electrode are repeatedly performed on the connection portion.   The connection device according to claim 5, wherein the temperature of the electronic component is increased and the internal circuit of the electronic component is inspected.   The connection device according to claim 1, wherein the platinum group metal layer is a palladium plating layer.

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