Patent ID: 12244083

BRIEF DESCRIPTION OF EMBODIMENTS

(A) Basic Concept

An embodiment of an electrical connecting apparatus according to the present disclosure will now be described with reference to the drawings.

An electrical connecting apparatus herein is a device for electrically connecting an electrode region that is provided on a first wiring substrate with an electrode region that is provided on a second wiring substrate. Accordingly, the electrical connecting apparatus can be applied to various devices, equipment, and the like. For example, the electrical connecting apparatus can be applied to a circuit device for electrically connecting circuit substrates equipped in a personal computer or the like, a unit for electrically connecting wiring substrates forming a probe card, and the like.

First, the basic concept of an electrical connecting structure between electrode regions of a wiring substrate in an electrical connecting apparatus according to an embodiment will be described with reference to the drawings.

FIG.1shows the configuration of the electrical connecting structure between the electrode regions of the wiring substrate in the electrical connecting apparatus according to the embodiment.FIG.1is a sectional view between the electrode regions of the wiring substrate.

As illustrated inFIG.1, the electrical connecting structure illustrates a structure for electrically connecting an electrode region11of a first wiring substrate10with an electrode region21of a second wiring substrate20using a connector30.

An electric circuit13is formed on the first wiring substrate10, and the electrode region (hereinafter, also referred to as the “upper electrode region”)11to be electrically connected with the electric circuit13is disposed on a lower surface12of the first wiring substrate10.

In the electrode region11, the lower surface12of the first wiring substrate10is formed to have a recessed part111that is depressed in the thickness direction of the substrate. A liquid metal5is filled inside the recessed part111. In addition, an inner surface of the recessed part111of the electrode region11(i.e., a wall surface part and an upper bottom part of the recessed part111) is provided with a metal layer113that is formed with a metal material such as, for example, copper and gold.

Furthermore, an upper part of the recessed part111in the electrode region11is provided with an electrode portion (hereinafter, also referred to as the “upper electrode portion”)112. This upper electrode portion112is electrically connected with the electric circuit13formed on the first wiring substrate10.

An electric circuit23is formed on the second wiring substrate20, and the electrode region (hereinafter, also referred to as the “bottom electrode region”)21to be electrically connected with the electric circuit23is disposed on an upper surface22of the second wiring substrate20.

In the electrode region21, the upper surface22of the second wiring substrate20is formed to have a recessed part211that is depressed in the thickness direction of the substrate, and the liquid metal5is filled inside the recessed part211. In addition, an inner surface of the recessed part211of the electrode region21(i.e., a wall surface part and a lower bottom part of the recessed part211) is provided with a metal layer213that is formed with a metal material such as, for example, copper and gold.

Furthermore, a lower part of the recessed part211in the electrode region21is provided with an electrode portion (hereinafter, also referred to as the “lower electrode portion”)212. This lower electrode portion212is electrically connected with the electric circuit23formed on the second wiring substrate20.

The liquid metal5is preferably in a liquid state in a use environmental temperature of the circuit device. For example, a metal having a melting point at room temperature (for example, about 30° C.) and under is preferably used, and for example, a metal having a melting point at −40° C. to 20° C. is further preferably used. The liquid metal5may be one kind of metal, or it may be an alloy that is composed of a plurality of liquid metals. For example, a metal such as gallium (Ga), indium (In), stannum (Sn), nickel (Ni) or the like, or an alloy having these as metallic alloys may be applied to the liquid metal5. More specifically, a eutectic metal (for example, Galinstan (registered trademark)) of gallium, indium, and stannum may be applied. The metallic composition ratio of the liquid metal composed of a plurality of metals is not particularly limited, and various ratios may be applied.

The recessed part111in the electrode region11of the first wiring substrate10and the recessed part211in the electrode region21of the second wiring substrate20may be filled with the liquid metal5having the same metallic composition, or the liquid metal5having different metallic compositions may be filled.

The connector30is a member for electrically connecting the electrode region11of the first wiring substrate10with the electrode region21of the second wiring substrate20. The connector30is a member that is formed of a conductive material.

An upper part31of the connector30electrically contacts the liquid metal5filled in the recessed part111of the first wiring substrate10, and a lower part32of the connector30electrically contacts the liquid metal5filled in the recessed part211of the second wiring substrate20, thereby realizing an electrical connection between the electrode region11of the first wiring substrate10and the electrode region21of the second wiring substrate20. In other words, not only one end of the connector30contacts the liquid metal5, but both ends of the connector30contact the liquid metal5in the electrode regions11,21of each wiring substrate.

In the prior art, as an example of an electrical connecting structure between electrodes using a connector, an electrical connection between electrodes is realized by bringing a tip of the connector into electrical contact with an electrode terminal at one point or multiple points. In such electrical connecting structure, a contact area between the tip of the connector and the electrode terminal is small, and contact resistance is increased. Thus, a stable electrical connecting property between the connector and each electrode terminal is required.

In contrast, in this embodiment, a contact area between the liquid metal5and the connector30can be expanded, and contact resistance can be suppressed, by bringing both ends of the connector30into contact with the liquid metal5in the electrode region11and the electrode region21of each wiring substrate. As a result, the electrical connecting property between the connector30, and the electrode region11and the electrode region21, can be stabilized.

In addition, as will be described later, by giving characteristics to the shape, the length, and the like of the connector30, the connector30and the liquid metal5can be brought into contact in a state receiving buoyancy of the liquid metal5in the electrode region11and the electrode region21. Accordingly, a stable electrical connecting property can be retained even if variations may occur in the length of the distance between the electrode region11and the electrode region21.

(B) First Embodiment

A first embodiment of the electrical connecting apparatus according to the present disclosure will now be described in detail with reference to the drawings.

The first embodiment illustrates an embodiment in which the electrical structure between the electrode regions according to the electrical connecting apparatus described above is applied to a probe card to be used for an electrical inspection on an inspection object such as an integrated circuit that is formed on a wafer. In the following, descriptions will be made by also referring toFIG.1.

(B-1) Configuration of First Embodiment

[Probe Card]

FIG.2shows the configuration of the probe card according to the first embodiment.

Although a probe card80inFIG.2illustrates main structural members, the probe card80is not limited thereto. Actually, structural members not illustrated inFIG.2are also provided. In the following, “upper” and “lower” will be referred to by focusing on the vertical direction inFIG.1.

InFIG.2, the probe card80according to this embodiment includes a flat support member81, a flat wiring substrate82that is retained on a lower surface of the above-described support member81, an electrical connecting unit83to be electrically connected with the above-described wiring substrate82, and a probe substrate84being electrically connected with the above-described electrical connecting unit83and having a plurality of electrical contactors (hereinafter, also referred to as the “probes”)85.

The probe card80uses multiple fixing members (for example, screwing members such as bolts) when assembling the support member81, the wiring substrate82, the electrical connecting unit83, and the probe substrate84. However,FIG.2does not illustrate these fixing members.

The probe card80sets, for example, an integrated circuit that is formed on a wafer, as an inspection object86, and performs an electrical inspection on the inspection object86. Specifically, the inspection object86is pressed toward the probe substrate84, and the tip part of each probe85on a lower surface of the probe substrate84is brought into an electrical contact with an electrode terminal of the inspection object86. An electrical signal is supplied to the electrode terminal of the inspection object86from the inspection device (not illustrated), and the electrical signal from the electrode terminal of the inspection object86is given to the inspection device side, thereby performing the electrical inspection on the inspection object86.

The inspection object86, which is an inspection target, is placed on an upper surface of a chuck top (not illustrated). The chuck top is capable of adjusting positions in an X-axis direction in the horizontal direction, a Y-axis direction that is vertical to the X-axis direction on a horizontal plane, and a Z-axis direction that is vertical to the horizontal plane (X-Y plane). Furthermore, rotating postures can be adjusted in a e direction around the Z axis.

When performing the electrical inspection on the inspection object86, a chuck that is capable of elevating in the vertical direction (Z-axis direction) is moved, and the lower surface of the probe substrate84of the probe card80and the inspection object86on the upper surface of the chuck top are moved to become relatively closer in order to bring the electrode terminal of the inspection object86into electrical contact with the tip part of each probe85of the probe substrate84.

[Support Member]

The support member81suppresses deformation (for example, deflection or the like) of the wiring substrate82. For example, since the probe substrate84has multiple probes85, the weight of the probe substrate84attached to the wiring substrate82side is large. In addition, when performing the electrical inspection on the inspection object86, the probe substrate84is pressed against the inspection object86such that the tip part of the probe85that is projected to the lower surface of the probe substrate84contacts the electrode terminal of the inspection object86. In this manner, at the time of the electrical inspection, a large load is also applied to the wiring substrate82due to the action of reaction force (contact load) that is pushed up from bottom to top. The support member81functions as a member for suppressing deformation (for example, deflection or the like) of the wiring substrate82.

In addition, the support member81has a plurality of through holes that penetrate the upper surface and the lower surface, and a spacer (support part)88is inserted through each through hole, thereby achieving a configuration that is capable of fixing the lower end part of the spacer (support part)88and a corresponding anchor87. In this manner, the probe substrate84and the support member81can be adjusted in the height direction.

[Wiring Substrate]

The wiring substrate82is made of, for example, a resin material such as polyimide, and is, for example, a printed substrate or the like that is formed in a substantially circular plate shape. Multiple electrode terminals (not illustrated) for an electrical connection with a test head (not illustrated) of a tester (inspection device) are disposed in the periphery of the upper surface of the wiring substrate82.

A wiring pattern is formed on the wiring substrate82, and the lower surface of the wiring substrate82is provided with a plurality of the electrode regions (upper part electrode regions)11to be electrically connected with the wiring pattern.

Each electrode region11formed on the lower surface of the wiring substrate82can have the same configuration as the upper part electrode region11illustrated inFIG.1.

Each electrode region (upper part electrode region)11includes the recessed part111depressed in the thickness direction on the lower surface of the wiring substrate82, the metal layer113on the inner surface of the recessed part111, the liquid metal5filled in the recessed part111, and the electrode portion (upper electrode portion)112to be electrically connected with the metal layer113in the upper bottom part of the recessed part111. The upper electrode portion112is in an electrical connection with the wiring pattern formed on the wiring substrate82.

The liquid metal5is filled in the recessed part111of the electrode region11, and the upper part31of each connector30in the electrical connecting unit83electrically contacts the liquid metal5filled in the recessed part111of the electrode region11.

A wiring circuit is formed inside the wiring substrate82, and the wiring pattern on the lower surface of the wiring substrate82and the electrode terminal on the upper surface of the wiring substrate82are connectable through the wiring circuit inside the wiring substrate82. Accordingly, an electrical signal can be conducted between each connector30electrically connected with the liquid metal5in the electrode region11of the wiring pattern on the lower surface of the wiring substrate82, and the test head connected to the electrode terminal on the upper surface of the wiring substrate82, through the wiring circuit inside the wiring substrate82. A plurality of electronic components that are necessary for the electrical inspection of the inspection object86are disposed on the upper surface of the wiring substrate82. Furthermore, in the wiring substrate82, insertion holes are provided at positions corresponding to the position of each insertion hole provided for the support member81. The height of the probe card80can be adjusted by inserting the spacer88into each insertion hole.

[Probe Substrate]

The probe substrate84is a substrate having the probes85, and is formed in a substantially circular shape or polygonal shape (for example, hexadecagon or the like). For example, the probe substrate84has a multilayer wiring substrate that is formed with a plurality of wiring substrates. In the probe substrate84as a multilayer wiring substrate, a wiring path (not illustrated) is formed among the multilayer substrates. One end of this wiring path is electrically connected with the electrode (lower electrode)212of the corresponding wiring pattern on the upper surface of the probe substrate84, and the other end of the wiring path is electrically connected with the connection terminal of the probes85provided on the lower surface of the probe substrate84.

A plurality of the electrode regions21are provided on the upper surface of the probe substrate84. Each electrode region21on the upper surface of the probe substrate84can have the same configuration as the lower part electrode region21illustrated inFIG.1.

Each electrode region (lower part electrode region)21includes, on the upper surface of the probe substrate84, the recessed part211depressed in the thickness direction, the metal layer213on the inner surface of the recessed part211, the liquid metal5filled in the recessed part211, and the electrode portion (lower electrode portion)212to be electrically connected with the metal layer213in the lower bottom part of the recessed part211. The lower electrode portion212is electrically connected with the wiring pattern of the probe substrate84.

In addition, the recessed part211of the electrode region21is filled with the liquid metal5, and the lower part32of each connector30in the electrical connecting unit83electrically contacts the liquid metal5filled in the recessed part211of the electrode region21.

Accordingly, each probe85provided on the lower surface of the probe substrate84is electrically connected with the lower electrode212of the probe substrate84through the wiring path of the probe substrate84, and is electrically connected with the corresponding electrode region11of the wiring substrate82through the connector30of the electrical connecting unit83.

[Electrical Connecting Unit]

The electrical connecting unit83electrically connects the wiring substrate82and the probe substrate84. The electrical connecting unit83is equipped with a plurality of the connectors30, and the upper part31of each connector30is brought into electrical contact with the liquid metal5of the upper part electrode region11, and the lower part32of each connector30is brought into electrical contact with the liquid metal5of the lower part electrode region21, thereby electrically connecting the upper part electrode region11and the lower part electrode region21.

[Electrical Connecting Structure Between Electrode Regions Using Connector]

With reference toFIG.1, a structure for electrically connecting the electrode region (upper part electrode region)11of the wiring substrate82with the electrode region (lower part electrode region)21of the probe substrate84by using the connector30will be described.

As exemplified inFIG.1, by bringing both ends of the connector30into contact with the liquid metal5provided in the electrode region11of the wiring substrate82and with the liquid metal5in the electrode region21of the probe substrate84, a contact area between the liquid metal5and the connector30can be expanded, and contact resistance can be suppressed. As a result, an electrical connecting property between the connector30, and the electrode region11and the electrode region21can be stabilized.

The states of the upper part electrode region11and the lower part electrode region21when the liquid metal5is filled in the recessed part111of the wiring substrate82and the recessed part211of the probe substrate84will now be described.

Although the state of the upper part electrode region11of the wiring substrate82will be described below, the lower part electrode region21of the probe substrate84will also become the same state as the upper part electrode region11, and the same effect can be exerted.

When filling the liquid metal5in the recessed part111in the upper part electrode region11of the wiring substrate82, in a lower part opening of the recessed part111, the liquid metal5contacts the air, and an oxide film51is formed by oxidation of the surface of the liquid metal5. Since the oxide film51has high viscosity, and the value of surface tension of the liquid metal5filled in the recessed part111is high, movement (dropping) from the recessed part111of the liquid metal5to the lower part can be suppressed.

Since the liquid metal5filled in the recessed part111of the wiring substrate82is coated with the oxide film51, the liquid metal5existing inside the oxide film51is prevented from contacting the air, and thus oxidation, vaporization, and the like of the liquid metal5inside the oxide film51can be suppressed. Accordingly, conductivity can be secured by bringing the liquid metal5inside the oxide film51into contact with the connector30.

When filling the liquid metal5in the recessed part111in the electrode region11of the wiring substrate82, acid treatment is performed on the surface of the metal layer113in order to prevent oxidation of the liquid metal5at a contact surface of the metal layer113on the inner surface of the recessed part111with the liquid metal5. In this manner, since oxidation of the liquid metal5contacting the metal layer13can be prevented, an electrical connection between the liquid metal5, which electrically contacts the connector30, and the metal layer113can be secured. With regard to the acid treatment, for example, a method in which the surface of the metal layer113is washed with an acidic solvent can be applied. However, the method of the acid treatment is not limited thereto, and various methods can be widely applied.

[Length of Connector and Length of Distance Between Electrode Regions]

FIG.3is an explanatory view for explaining a length of the connector30according to the first embodiment.

The length of the connector30for electrically connecting the upper part electrode region11of the wiring substrate82with the lower part electrode region21of the probe substrate84can be determined in relation to the length of the distance between the upper part electrode region11and the lower part electrode region21.

InFIG.3, the length of the distance between the position of the upper bottom part113in the metal layer113of the recessed part111in the upper part electrode region11and the position of the lower bottom part213in the metal layer213of the recessed part211in the lower part electrode region21(hereinafter, also referred to as the “length of the distance between the electrode regions”) is denoted “X”. At this time, when the full length of the connector30is denoted “Y”, the full length Y of the connector30can be made smaller than the distance length X (X>Y).

In this manner, by setting the full length of the connector30smaller than the length of the distance between the electrode regions, the upper part31and the lower part32of the connector30contacts the inner liquid metal5coated with the oxide film51, and receives buoyancy from each liquid metal5, and the connector30can be in a floatable state.

In addition, when the connector30is in a floated state by receiving buoyancy of the liquid metal5of the upper part electrode region11and the lower part electrode region21, the connector30may fall down. Thus, the full length of the connector30is desirably set to a length that is supported by the inner surfaces of the recessed part111and the recessed part211in the upper part electrode region11and the lower part electrode region21.

Furthermore, as illustrated inFIG.3, if the recessed part111in the upper part electrode region11and the recessed part211in the lower part electrode region21have the same shapes, and the recessed part111and the recessed part211are in positions opposing in the vertical direction, when the diameter of the recessed part111(or the recessed part211) is denoted “a” and the length of the distance between the position of the opening part of the recessed part111and the position of the opening part of the recessed part211is denoted “b”, the full length Y of the connector30can be set to distance length Z(=(a2+b2)1/2) and over (Y≥Z). In this manner, even if the connector30collapses, the connector30can be prevented from falling down since the end part of the connector30will contact the inner surfaces of the recessed part111and the recessed part211.

As described above, by at least setting the full length of the connector30smaller than the length of the distance between the electrode regions, both ends of the connector30can be brought into contact with the liquid metal5of each electrode region11,12, and the connector30can float in a state receiving buoyancy from the liquid metal5. As a result, an electrical connection between the upper part electrode region11and the lower part electrode region21can be performed in a state in which the liquid metal5of the upper part electrode region11and the lower part electrode region21is in electrical contact with the connector30.

The recessed part111in the upper part electrode region11and the recessed part211in the lower part electrode region21may have shapes that are depressed in a column shape, prism shape, truncated pyramid, or the like, in the thickness direction of the substrate. In addition, the thickness length of the recessed part111and the recessed part211in the thickness direction of the substrate may be determined as appropriate in accordance with the operation.

[End Part Shape of Connector]

FIG.4illustrates a shape example of the connector30according to the first embodiment.

The end part of the connector30may have a contact expanding shape part that expands contact with the liquid metal5. This contact expanding shape part is a shape part in which parts among the connector30to be brought into contact with the liquid metal5are processed such that a contact area with the liquid metal5is expanded. For example, shape parts as illustrated inFIG.4(B)toFIG.4(D)can be applied.

The shapes of both end parts of the connector30may be processed, or the shape of either one of both end parts may be processed. Furthermore, the shapes of both end parts of the connector30may be processed to have the same shape, or both end parts may be processed in different shapes.

The cross-sectional shape of the connector30may be in, for example, a circle shape, an oval shape, a square, a polygon, or the like. In addition, various shapes can be used for the shape of the connector30, and the shape is not limited to those illustrated inFIG.3(A)toFIG.3(D).

FIG.4(A)illustrates a case of a rod-like member in which the cross-sectional shape of the connector30is a square. According to the connector30illustrated inFIG.4(A), the electrical connecting property between the upper part electrode region21and the lower part electrode region21can be stabilized while simplifying the shape of the connector30. The cross-sectional shape of the connector30may be in, for example, a circle shape, an oval shape, a polygon, or the like.

FIG.4(B)illustrates a case in which each of the upper part31and the lower part32of the connector30is provided with a slit part (groove part)311. As illustrated inFIG.4(B), by providing the slit part311for the upper part31and the lower part32of the connector30, a wall surface of the slit part311also contacts the liquid metal5. Thus, the contact area between the liquid metal5and the connector30can be further expanded, and good electrical connecting property between the connector30and the liquid metal5can be achieved.

As long as a configuration in which the contact area between the connector30and the liquid metal5is expanded is achieved, a plurality of the slit parts311may be provided for the upper part31and the lower part32of the connector30. In addition, instead of the slit part311, one or a plurality of through holes or one or a plurality of non-penetrating hole parts (recessed parts) may be provided, or one or a plurality of protruding parts may be provided. AlthoughFIG.4(B)illustrates a case in which the cross-sectional shape of the connector30is a circle shape, the cross-sectional shape of the connector30may be an oval shape, a square, a polygon, or the like.

FIG.4(C)illustrates a case in which each of the upper part31and the lower part32of the connector30is formed in a conical shape or a square pyramid shape having a flat tip. In other words, the upper part31and the lower part32of the connector30have tapered shapes in which the diameter becomes narrower towards the tip side. As shown inFIG.4(C), by forming the upper part31and the lower part32of a connector30in a spindle shape, the oxide film51formed on the surface of the liquid metal5can be broken, and contact with the liquid metal5can be realized. In addition, since the tip of the spindle shape is flat, the connector30is easily floatable by receiving buoyancy of the liquid metal5.

FIG.4(D)illustrates a case in which each of the upper part31and the lower part32of the connector30has a tapered shape in which the diameter becomes larger towards the tip side. In this manner, the upper part31and the lower part32of the connector30easily receive buoyancy from the liquid metal5, and due to a surface tension of the liquid metal5, the connector30can retain a stable posture (i.e., in the case ofFIG.1, a standing posture in the vertical direction). In addition, the contact area between the connector30and the liquid metal5can be expanded. As a result, the electrical connecting property between the upper part electrode region11and the lower part electrode region21can be stabilized.

(B-3) Effect of First Embodiment

As described above, according to the first embodiment, by bringing both ends of the connector into contact with the liquid metals in the electrode region of the wiring substrate and in the electrode region of the probe substrate, a contact area between the liquid metal and the connector can be expanded, and contact resistance can be suppressed. As a result, an electrical connecting property between the connector and the electrode regions can be stabilized.

In addition, according to the first embodiment, by characterizing the shape, the length, and the like of the connector, the connector can be brought into contact with the liquid metal in a state receiving buoyancy of the liquid metals of the electrode regions. Accordingly, a stable electrical connecting property can be retained even if variations may occur in the length of the distance between the electrode regions.

(C) Other Embodiment

Although various modified embodiments were referred to also in the embodiment described above, the present disclosure can also be applied to the following modified embodiments.

(C-1) Although application of the electrical connecting structure between the electrode regions described above to a probe card is illustrated, the electrical connecting structure between the electrode regions described in the basic concept can be applied to a circuit device for electrically connecting electrode regions (electrode portions) of a wiring substrate.

For example, the circuit device may be used for, for example, a circuit device to be equipped in a device, equipment, or the like such as a personal computer. Even when the electrical connecting structure between the electrode regions described in the basic concept is applied to such circuit device, a contact area with the connector is expanded and contact resistance can be suppressed, and thus a stable electrical connecting property can be maintained. In addition, even when the electrical connecting structure between the electrode regions described in the basic concept is applied to the circuit device, the length, the shape, and the like of the connector may be those described inFIG.2andFIG.3, and the same effect can be exerted.

(C-2) The basic concept and the first embodiment described above illustrate a case in which the electrode regions to be electrically connected using the connector are provided in the vertical direction. As illustrated inFIG.5, application can be made also to a case in which the electrode regions are provided in the horizontal direction. In that case, the shape of the connector30may be that illustrated inFIG.3, or may be a shape in which both ends of the connector30can float in the liquid metal5of the two electrode regions11and12. For example, as illustrated inFIG.5(A), the connector30may be a member having an arc-like shape or a substantially U-shape that is downwardly convex. Furthermore, as illustrated in FIG.5(B), the connector30may be a member having a substantially V-shape. The same effect can be exerted also in this case.

REFERENCE SIGNS LIST

1electrical connecting structure80probe card81support member82wiring substrate83electrical connecting unit84probe substrate85electrical contactor86inspection object10first wiring substrate11electrode region12lower surface of the first wiring substrate13electric circuit111recessed part112electrode portion (upper electrode portion)113metal layer20second wiring substrate21electrode region of2022upper surface of the second wiring substrate23electric circuit211recessed part212electrode portion (lower electrode portion)213metal layer30connector