JP4999398B2 - Wiring board - Google Patents

Description

  The present invention relates to a wiring board configured by mechanically bonding a plurality of boards in an electrically conductive state, and particularly suitable for application to a board for a device interface such as a probe card, a performance board, or a socket board. Regarding the substrate.

  When an electronic component having a semiconductor integrated circuit (hereinafter also referred to as an IC device) is manufactured, an IC device is used in a semiconductor wafer stage (pre-stage) or a finished product stage after packaging (post-process). Has been tested. In the test of an IC device, the test is performed by electrically contacting a large number of contact pins mounted on a probe card or socket with an input / output terminal of the IC device and exchanging electrical signals.

  As shown in FIG. 8, a wiring board 10 ′ for a device interface such as a probe card, a performance board, or a socket board used for testing such an IC device includes a first board 20 and a second board 30 and an interposer 40. It is configured to be bonded together in an electrically connected state.

The interposer 40 includes a large number of elastic pins 41 and a support plate 42 that supports the pins 41 at a substantially intermediate position. The first pins 20 are formed on the first substrate 20 by the pins 41. The terminal 21 and the second terminal 31 formed on the second substrate 30 are electrically connected. Examples of other interposers include pogo pins and anisotropic conductive rubber sheets (those in which gold-plated fine wires are embedded at high density in silicone rubber).

  The first substrate 20, the second substrate 30, and the interposer 40 are mechanically fixed to a stiffener 60 (reinforcing plate) with bolts 50, whereby the substrates 20, 30 are warped by the elastic force of the interposer 40. The occurrence is suppressed. In the probe card, an opening (not shown) is formed in the approximate center of the stiffener 60, and several thousand or more probe needles (not shown) are provided so as to face the pads of the IC device under test built on the wafer. Therefore, the entire substrate cannot be pressed uniformly, and the substrate may be bent and warped. Further, there is a difficulty in that parts such as a large number of connectors (not shown) for relaying signals cannot be arranged in the area where the stiffener 60 is present on the board.

In the wiring board 10 ′ for a device interface having the above-described configuration, a member (interposer 40) for electrically connecting the substrates 20 and 30 and the substrates 20 and 30 are mechanically fixed while maintaining an elastic state. Since the member (bolt 50) for doing so is composed of separate parts, the number of parts is increased. In particular, the space for disposing the member 50 for mechanical fixing does not contribute to the electrical connection between the substrates 20 and 30, and thus hinders high-density mounting that has been required more recently.

Further, as described above, the stiffener 60 is provided in order to suppress the warpage of the substrates 20 and 30 due to the elasticity of the pins 41, and the number of parts is also increased in this respect.

  Furthermore, one substrate 30 may be heated / cooled to +130 to −30 ° C., but since both the substrates 20 and 30 are forcibly fixed with bolts 50, thermal expansion due to temperature difference occurs. Stress is generated in the wiring board 10.

  Further, in order to ensure electrical connection between the substrates 20 and 30 and the interposer 40, a positioning mechanism (not shown) is required to position them with high accuracy.

  An object of the present invention is to provide a wiring board capable of reducing the number of components and absorbing thermal expansion of the board.

(1) In order to achieve the above object, according to the present invention, the first terminal formed on the first substrate is electrically connected to the second terminal formed on the second substrate. A wiring board configured by mechanically bonding the first board and the second board in a state, wherein the first board faces the second board. The second substrate is mounted on the first substrate and has a first magnetic body electrically connected to the first terminal, and the second substrate faces the first magnetic body. is mounted on, the has a second magnetic body that is electrically connected to the second terminal, at least one of the first magnetic body or the second magnetic body is a magnet, the first One magnetic body and / or the second magnetic body is mounted on the first substrate and / or the second substrate via an elastic body. The when the bonding of the first substrate and the second substrate, the first magnetic body and said second magnetic body in close contact by magnetic force, the second terminal and the first terminal And a wiring board characterized by being electrically connected to each other (see claim 1).

  In the present invention, when the first substrate and the second substrate are bonded together, the first terminal and the second terminal are electrically connected by bringing the first magnetic body and the second magnetic body into close contact with each other by magnetic force. And conducting bonding between the first substrate and the second substrate.

  As a result, a component for electrically connecting the first terminal and the second terminal, and a component for holding the first substrate and the second substrate to be bonded to each other can be obtained. The two magnetic bodies can be shared, and the number of parts can be reduced. That is, in the present invention, two functions of electrical continuity of terminals and bonding of substrates can be achieved by one component (magnetic material).

In general, since the magnetic force is relatively weak with respect to the force applied from the direction perpendicular to the magnetic field, in the present invention, when the thermal expansion coefficients of the first substrate and the second substrate are different, The first magnetic body and the second magnetic body slide by an amount corresponding to the deviation due to thermal expansion, and the thermal expansion can be absorbed.
Moreover, even if the height of each terminal varies, the variation can be absorbed, so that all the terminals can be brought into contact at the same time.

  Although not particularly limited in the above invention, it is preferable that the first magnetic body is a ferromagnetic body and the second magnetic body is also a ferromagnetic body.

Although not particularly limited in the above invention, the elastic body preferably has electrical conductivity (see claim 2).
Although not particularly limited in the above invention, it is preferable that both the first magnetic body and the second magnetic body are permanent magnets (see claim 3 ).

Although not particularly limited in the above invention, it is preferable that the first magnetic body is a permanent magnet and the second magnetic body is made of a ferromagnetic metal material (see claim 4 ).

Although not particularly limited in the above invention, the first magnetic body is located on the first terminal, and the second magnetic body is located on the second terminal. It is preferable (see claim 5 ).

Although not particularly limited in the above invention, the first magnetic body and / or the second magnetic body is composed of a permanent magnet body and a metal plating layer formed on the surface of the permanent magnet body. (See claim 6 ).

  In order to achieve the above object, according to the present invention, the probe needle mounted on the wiring board in order to make electrical contact with the wiring board and the pad of the electronic component under test formed on the semiconductor wafer. And a probe card (see claim 7).

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is an exploded sectional view showing a wiring board according to the first embodiment of the present invention, and FIG. 2 is an enlarged sectional view of a portion II in FIG.

  As shown in FIG. 1, the laminated wiring board 10 in the present embodiment includes a first board 20 to which a probe needle unit (not shown) and the like are electrically connected and a tester (both not shown). ) And the second substrate 30 electrically connected to each other, and is a wiring substrate used as a device interface substrate such as a probe card. This laminated wiring board 10 is used, for example, when the pitch of the probe needle unit corresponding to the narrow pitch of the input / output terminals of the IC device is converted to a relatively wide pitch on the test head side. Also, depending on the type of IC device under test formed on the wafer, if one substrate can be used in common, and only the other substrate can be replaced to support product replacement, the equipment cost can be reduced. Can be planned.

  As shown in FIG. 2, the first substrate 20 includes a substrate body 24 made of a synthetic resin material having excellent heat resistance, such as a glass epoxy resin, and a first body formed on the surface of the substrate body 24. This is a printed circuit board (PCB) including a terminal 21 and an upper terminal 22 and a through hole 23 that electrically connects the terminals 21 and 22.

  The first terminal 21 is composed of a gold pad or the like formed on the lower surface of the substrate body 24 so as to face the second substrate 30 by using a technique such as vacuum deposition or sputtering. The upper terminal 22 is also composed of a gold pad or the like formed on the upper surface of the substrate body 22 and is electrically connected to the probe needle unit. The first terminal 21 and the upper terminal 22 are electrically connected by a through hole 23 made of gold or the like formed so as to penetrate the substrate body 24. Instead of the through hole 23, a non-through hole (SVH: Surface Via Hole) may be applied. This facilitates passage of many thousands of pattern wirings.

  Further, in the present embodiment, the permanent magnet 25A is mounted on the first terminal 21 (under the first terminal 21 in FIG. 2) via the first elastic body 26. The permanent magnet 25A is composed of a magnet having an electrically low resistance characteristic of, for example, several Ω or less. The permanent magnet 25A is joined to the first terminal 21 by soldering or a conductive adhesive, and electrical connection can be established between the first terminal 21 and the permanent magnet 25A. .

  The first elastic body 26 interposed between the first terminal 21 and the permanent magnet 25A is composed of an elastic body having conductivity such as silicone rubber containing carbon or an anisotropic conductive rubber sheet. Thus, the first terminal 21 and the permanent magnet 25A can be electrically connected via the first elastic body 26.

  Further, as shown in FIG. 1, positioning through holes 27 are formed in the substrate body 24 of the first substrate 20. In the present embodiment, the inner diameter of the through hole 27 is formed relatively large with respect to the outer diameter of the positioning pin 37 provided on the second substrate 30 in consideration of the difference in thermal expansion between the two substrates. Even when the positioning pins 37 are inserted into the through holes 27, the first substrate 20 and the second substrate 30 can be moved minutely with respect to each other.

  As shown in FIG. 1, the second substrate 30 also includes a substrate body 34 made of a synthetic resin material having excellent heat resistance such as glass epoxy resin, and a second body formed on the surface of the substrate body 34. This is a printed circuit board (PCB) including a terminal 31, a lower terminal 32, and a through hole 33 that electrically connects the terminals 31 and 32.

  The second terminal 31 is, for example, a gold pad formed on the upper surface of the substrate body 34 so as to face the first terminal 21 formed on the first substrate 20 using a technique such as vacuum deposition or sputtering. It is composed of The lower terminal 32 is also composed of a gold pad or the like formed on the lower surface of the substrate body 34, and is electrically connected to the tester so that signals can be exchanged via the test head. The second terminal 31 and the lower terminal 32 are electrically connected by a through hole 33 made of gold or the like formed so as to penetrate the substrate body 34.

  Further, in the present embodiment, the permanent magnet 35 </ b> A is mounted on the second terminal 31 via the second elastic body 36. The permanent magnet 35A is made of a magnet having an electrically low resistance characteristic of, for example, several Ω or less. The permanent magnet 35A is joined to the second terminal 31 by soldering or a conductive adhesive, and electrical connection can be established between the second terminal 31 and the permanent magnet 35A. .

  The second elastic body 36 interposed between the second terminal 31 and the permanent magnet 35A is made of an elastic body having conductivity such as silicon rubber containing carbon, for example. The terminal 31 and the permanent magnet 36 </ b> A can be electrically connected via the second elastic body 36.

  Further, positioning pins 37 projecting toward the second substrate 30 are provided on the substrate body 34 of the second substrate 30. When the first substrate 20 and the second substrate 30 are bonded to each other, the positioning pins 37 are inserted into the through holes 27 formed in the first substrate 20, so that the second substrate 30 becomes the first substrate. 20 is positioned.

  Next, the operation will be described.

  In configuring the multilayer wiring substrate 10, first, the first substrate 20 is inserted into the through hole 27 while the positioning pins 37 are inserted with the lower surface of the first substrate 20 and the upper surface of the second substrate 30 facing each other. 20 and the second substrate 30 are bonded together.

At this time, the first permanent magnet 25A mounted on the first substrate 20 and the second permanent magnet 35A mounted on the second substrate 30 are attracted to each other by the magnetic force, so that the first permanent magnet 25A The terminal 21 and the second terminal 31 are electrically connected via the permanent magnets 25 </ b> A and 35 </ b> A and the elastic bodies 26 and 36. In addition, the bonding between the first substrate 20 and the second substrate 30 is held by the magnetic force of the first permanent magnet 25A and the second permanent magnet 35A.

As described above, in this embodiment, the permanent magnets 25A and 35A provide electrical continuity between the terminals 21 and 31 and hold the substrates 20 and 30 together. For this reason, the components for electrically connecting the terminals 21 and 31 and the components for mechanically bonding the substrates 20 and 30 can be shared by the permanent magnets 25A and 35A, thereby reducing the number of components. be able to. Moreover, the dead space which does not contribute to the electrical connection between the boards 20 and 30 can be reduced by reducing the number of parts.

Moreover, the terminals 21 and 31 are automatically positioned on a plane parallel to the main surfaces of the substrates 20 and 30 by the magnetic force of the permanent magnets 25A and 35A. Therefore, highly accurate positioning by the through hole 27 and the positioning pin 37 is unnecessary.

  Furthermore, generally, since the magnetic force is relatively weak with respect to the force applied from the direction perpendicular to the magnetic field, the permanent magnet is permanent by the amount of deviation generated when the substrates 20 and 30 having different thermal expansion coefficients are thermally expanded. Since the magnets 25 </ b> A and 35 </ b> A can slide and absorb the deviation amount, the stress in the multilayer wiring board 10 can be greatly reduced. In addition, since the conventional stiffener 60 can be eliminated, the entire wiring board can be effectively used. For example, the probe needles of the probe card can be arranged in a wider area, and components such as a large number of connectors (not shown) for relaying signals can be easily arranged, so that a highly flexible wiring board can be realized.

Even if the vertical heights of the terminals 21 and 31 on the substrates 20 and 30 are varied, the variation is caused by the elastic bodies 26 and 36 interposed between the terminals 21 and 31 and the permanent magnets 25A and 35A. Since all the terminals 21 and 31 can be brought into contact with each other at the same time.

  FIG. 3 is an enlarged cross-sectional view of a portion corresponding to part II of FIG. 1 in the wiring board according to the second embodiment of the present invention.

  The laminated wiring board according to the second embodiment of the present invention is the same as that of the first embodiment except that the structure of the permanent magnet mounted on the terminal is different. Only differences from the first embodiment will be described below.

  As shown in FIG. 3, the permanent magnet 25B mounted on the first substrate 20 in the present embodiment includes an electrically insulating magnet body 251 such as a rare earth magnet, and a gold formed on the surface thereof. And a metal plating layer 252 made of, for example.

  Although not specifically shown, the permanent magnet mounted on the second substrate 30 is also a metal plating layer made of an electrically insulating magnet body such as a rare earth magnet and gold formed on the surface thereof. And is composed of.

  In the present embodiment, when the first substrate 20 and the second substrate 30 are attached to each other, the permanent magnets are brought into close contact with each other by magnetic force, and the first terminal 21 and the first substrate 21 are connected to each other through the metal plating layer and the elastic body. The second terminal 31 is electrically connected. In addition, you may comprise the magnet main body of the permanent magnet in this embodiment with the magnet which has an electrically low resistance characteristic of several ohms or less similarly to 1st Embodiment, for example.

  FIG. 4 is an enlarged cross-sectional view of a portion corresponding to part II of FIG. 1 in the wiring board according to the third embodiment of the present invention.

  The multilayer wiring board according to the third embodiment of the present invention is different from the first embodiment in that the permanent magnet is mounted not on the first terminal but on the board body 24. Unlike the first embodiment, the other configuration is the same as that of the first embodiment. Only differences from the first embodiment will be described below.

  As shown in FIG. 4, in the present embodiment, the permanent magnet 25 </ b> A is mounted on the substrate body 24 of the first substrate 20 via the first elastic body 28 apart from the first terminal 21. The permanent magnet 25 </ b> A and the first terminal 21 are electrically connected via a conductor 29. Although not particularly illustrated for the second substrate 30, the permanent magnet 35 </ b> A is provided on the substrate body 34 of the second substrate 30 apart from the second terminal 31, similarly to the first substrate 20 shown in FIG. 4. Has been implemented.

  As in the first embodiment, the permanent magnet 25A is composed of a magnet having an electrically low resistance characteristic of, for example, several Ω or less. Further, unlike the first embodiment, the elastic body 28 in the present embodiment is configured by a non-conductive elastic body such as silicone rubber that does not contain carbon.

  FIG. 5 is an exploded sectional view showing a wiring board according to a fourth embodiment of the present invention.

  The multilayer wiring board according to the fourth embodiment of the present invention is different from the first embodiment in that a metal plate 35C is mounted on the second terminal 31 of the second substrate 30 instead of the permanent magnet. However, other than that is the same as the first embodiment.

  The metal plate 35C is a flat plate member made of a ferromagnetic material such as iron, nickel, cobalt, or an alloy containing these, and is joined to the second terminal 31 by soldering or a conductive adhesive. It is possible to establish electrical continuity between the metal plate 35C and the second terminal 31.

  Also in the present embodiment, as in the first embodiment, when the first wiring board 20 and the second board 30 are bonded to each other in configuring the multilayer wiring board, the first board mounted on the first board 20 is mounted. The permanent magnet 25A and the metal plate 35C mounted on the second substrate 30 are attracted to each other by magnetic force, and the first terminal 21 and the second terminal 31 are electrically connected.

  FIG. 6 is an exploded sectional view showing a wiring board according to a fifth embodiment of the present invention.

  In the multilayer wiring board according to the fifth embodiment of the present invention, the interposer 40 is interposed between the first substrate 20 and the second substrate 30 as in the conventional case, and the first terminal 21 and the second substrate 30 are arranged. The terminal 31 is electrically connected via a pin 41 of the interposer 40. Here, when it is required to arrange the terminals 21 and 31 at a narrow pitch, it is desirable to apply an anisotropic conductive rubber sheet to the interposer 40. At this time, it is desirable that the gold pads formed on the terminals 21 and 31 are formed thick so that the anisotropic conductive rubber sheet reduces the pressing load on the many unnecessary pins 41 that do not contribute to electrical connection. In addition, as for the anisotropic conductive rubber sheet to be used, it is desirable to use what can obtain favorable contact resistance with a low pressing load. Moreover, it is desirable to form an opening (not shown) in the interposer 40 so that the permanent magnet 25A can be mounted in an empty area where the pin 41 of the interposer 40 is not disposed.

  The permanent magnets 25 </ b> A are mounted at a plurality of dispersed locations on the lower surface of the first substrate 20. Similarly, a permanent magnet 35A is mounted on the upper surface of the second substrate 30 at a position facing the permanent magnet 25A. When the first substrate 20 and the second substrate 30 are bonded to each other via the interposer 40, the bonding between the first and second substrates 20 and 30 is held by the magnetic force of the permanent magnets 25A and 35A. Here, the permanent magnets 25 </ b> A and 35 </ b> A are arranged in an empty area where the pins 41 of the interposer 40 are not arranged and are arranged in a distributed manner so that all the pins 41 of the interposer 40 can be in good contact. It is desirable.

  In addition, the permanent magnets 25A and 35A slide by the amount of displacement generated when the first substrate 20 and the second substrate 30 having different thermal expansion coefficients thermally expand with temperature difference, and absorb the amount of displacement. Therefore, the stress in the multilayer wiring board can be greatly reduced. In addition, since the conventional stiffener 60 can be eliminated, the entire wiring board can be effectively used. For example, the probe needles of the probe card can be arranged in a wider area, and components such as a large number of connectors (not shown) for relaying signals can be easily arranged, thereby realizing a highly flexible wiring board.

  FIG. 7 is an exploded sectional view showing a wiring board according to the sixth embodiment of the present invention.

  In the multilayer wiring board according to the sixth embodiment of the present invention, the interposer 40 is interposed between the first substrate 20 and the second substrate 30 as in the above-described fifth embodiment.

  Similar to the fifth embodiment, permanent magnets 25 </ b> A are mounted at a plurality of dispersed positions on the lower surface of the first substrate 20. On the other hand, a metal plate 35 </ b> C similar to that described in the fourth embodiment is mounted at a position facing the upper surface of the second substrate 30. When the first and second substrates 20 and 30 are bonded together, the bonding between the first and second substrates 20 and 30 is held by the magnetic force of the permanent magnet 25A.

  In addition, the permanent magnet 25A and the metal plate 35C slide by the amount of deviation generated when the first and second substrates 20 and 30 having different thermal expansion coefficients thermally expand with temperature difference, and absorb the deviation. Therefore, the stress in the multilayer wiring board can be greatly reduced.

The embodiment described above is described for facilitating the understanding of the present invention, and is not described for limiting the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present invention.

  For example, in the above-described embodiment, an example in which the laminated wiring board 10 is applied to a probe card has been described. However, the present invention is not particularly limited thereto, and may be applied to, for example, a performance board or a socket board.

  In the first to fourth embodiments, the permanent magnet is mounted on the substrate via the elastic body. However, the present invention is not particularly limited, and the variation in the height direction of the terminal is small. Alternatively, a permanent magnet may be directly mounted without using an elastic body.

  Further, the permanent magnet 25B having the metal plating layer 251 described in the second embodiment and the permanent magnet 25A mounted on the substrate body 24 described in the third embodiment are applied in the third to sixth embodiments. You may do it.

  Furthermore, in the fourth embodiment, a conductive elastic body 26 may be interposed between the metal plate 35C and the second terminal 31. Thereby, the variation in the height direction of the second terminal 31 can be absorbed.

  In the fourth and sixth embodiments, the permanent magnet 25A is mounted on the first substrate 20 and the metal plate 35C is mounted on the second substrate 30. However, the present invention is not particularly limited to this. The metal plate 35 </ b> C may be mounted on one substrate 20, and the permanent magnet 25 </ b> A may be mounted on the second substrate 30.

FIG. 1 is an exploded sectional view showing a wiring board according to a first embodiment of the present invention. FIG. 2 is an enlarged cross-sectional view of a portion II in FIG. FIG. 3 is an enlarged cross-sectional view of a portion corresponding to the II part of FIG. 1 in the wiring board according to the second embodiment of the present invention. FIG. 4 is an enlarged cross-sectional view of a portion corresponding to the II part of FIG. 1 in the wiring board according to the third embodiment of the present invention. FIG. 5 is an exploded sectional view showing a wiring board according to the fourth embodiment of the present invention. FIG. 6 is an exploded sectional view showing a wiring board according to a fifth embodiment of the present invention. FIG. 7 is an exploded sectional view showing a wiring board according to a sixth embodiment of the present invention. FIG. 8 is an exploded sectional view showing a conventional wiring board.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Laminated wiring board 20 ... 1st board | substrate 21 ... 1st terminal 22 ... Upper side terminal 23 ... Through-hole 24 ... Board | substrate main body 25A, 25B ... Permanent magnet 251 ... Magnet main body 252 ... Metal plating layer 26 ... 1st elasticity Body 30 ... second substrate 31 ... second terminal 32 ... lower terminal 33 ... through hole 34 ... substrate body 35A ... permanent magnet 35C ... metal plate

Claims (7)

In a state where the first terminal formed on the first substrate and the second terminal formed on the second substrate are electrically connected, the first substrate and the second substrate are mechanically connected to each other. A wiring board constructed by sticking together,
The first substrate has a first magnetic body mounted on the first substrate so as to face the second substrate and electrically connected to the first terminal;
The second substrate has a second magnetic body mounted on the second substrate so as to face the first magnetic body and electrically connected to the second terminal,
At least one of the first magnetic body or the second magnetic body is a magnet,
The first magnetic body and / or the second magnetic body are mounted on the first substrate and / or the second substrate via an elastic body,
When the first substrate and the second substrate are bonded to each other, the first magnetic body and the second magnetic body are brought into close contact with each other by magnetic force, and the first terminal and the second terminal are A wiring board characterized by electrically conducting.   The wiring board according to claim 1, wherein the elastic body has conductivity.   The wiring board according to claim 1, wherein each of the first magnetic body and the second magnetic body is a permanent magnet.   2. The wiring board according to claim 1, wherein the first magnetic body is a permanent magnet, and the second magnetic body is made of a ferromagnetic metal material. The first magnetic body is located on the first terminal;
Said second magnetic body, the wiring board according to any one of claims 1-4, characterized in that rests on top of the second terminal. The first magnetic body and / or the second magnetic body are:
A permanent magnet body;
The wiring board according to claim 1, comprising a metal plating layer formed on a surface of the permanent magnet body. The wiring board according to claim 1;
A probe card comprising: a probe needle mounted on the wiring board for making electrical contact with a pad of an electronic device under test formed on a semiconductor wafer.

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