Semiconductor device

A semiconductor device includes a substrate, a semiconductor package including a semiconductor chip, and a connector between the substrate and the semiconductor package, the connector having opposing first and second planar surfaces, the first planar surface in contact with the substrate and the second planar surface in contact with the semiconductor package. The connector also includes a plurality of wires extending between the first and second planar surfaces to electrically connect electrodes of the substrate to electrodes of the semiconductor package.

CROSS-REFERENCE TO RELATED APPLICATION

This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2015-048663, filed Mar. 11, 2015, the entire contents of which are incorporated herein by reference.

FIELD

An embodiment described herein relates generally to a semiconductor device including an anisotropic conductive member.

BACKGROUND

Semiconductor devices which mount a semiconductor package using an anisotropic conductive member are known.

DETAILED DESCRIPTION

Embodiments now will be described more fully hereinafter with reference to the accompanying drawings. In the drawings, the thickness of layers and regions may be exaggerated for clarity. Like numbers refer to like elements throughout. As used herein the term “and/or” includes any and all combinations of one or more of the associated listed items and may be abbreviated as “/”.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms “a,” “an” and “the” are intended to include plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises,” “comprising,” “having,” “includes,” “including” and/or variations thereof, when used in this specification, specify the presence of stated features, regions, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, regions, steps, operations, elements, components, and/or groups thereof.

It will be understood that, although the terms first, second, etc. may be used herein to describe various elements, components, regions, layers and/or sections, such elements, materials, regions, layers and/or sections should not be limited by these terms. These terms are only used to distinguish one element, material, region, layer or section from another element, material, region, layer or section. Thus, a first element, material, region, layer or section discussed below could be termed a second element, material, region, layer or section without departing from the teachings of the present invention.

Relative terms, such as “lower”, “back”, and “upper” may be used herein to describe one element's relationship to another element as illustrated in the Figures. It will be understood that relative terms are intended to encompass different orientations of the device in addition to the orientation depicted in the Figures. For example, if the structure in the Figure is turned over, elements described as being on the “backside” of substrate would then be oriented on “upper” surface of the substrate. The exemplary term “upper”, may therefore, encompasses both an orientation of “lower” and “upper,” depending on the particular orientation of the figure. Similarly, if the structure in one of the figures is turned over, elements described as “below” or “beneath” other elements would then be oriented “above” the other elements. The exemplary terms “below” or “beneath” can, therefore, encompass both an orientation of above and below.

Embodiments provide a semiconductor device capable of improving mounting reliability of a semiconductor package.

According to an embodiment, a semiconductor device includes a substrate, a semiconductor package including a semiconductor chip, and a connector between the substrate and the semiconductor package, the connector having opposing first and second planar surfaces, the first planar surface in contact with the substrate and the second planar surface in contact with the semiconductor package. The connector also includes a plurality of wires extending between the first and second planar surfaces to electrically connect electrodes of the substrate to electrodes of the semiconductor package.

Hereinafter, Embodiments will be described with reference to drawings. In the following description, an element which has the same function and configuration will be denoted by the same reference numeral.

[1] Configuration of Semiconductor Device

With reference toFIGS. 1 and 2, a configuration of a semiconductor device according to an embodiment will be described.

As shown in the drawings, a semiconductor device1includes a substrate10, a semiconductor package20, an anisotropic conductive sheet30, and a member40.

The substrate10is a wiring board in which a circuit wiring is formed on an insulating substrate, and is, for example, a print wiring board. The substrate10has a first surface and a second surface, and a plurality of electrodes11are arranged on the first surface.

The semiconductor package20is made by enclosing a semiconductor chip in a package, and is, for example, a Ball Grid Array (BGA), a Chip Size Package (CSP), a Thin Small Outline Package (TSOP), and the like. An integrated circuit is formed in the semiconductor chip, as a result of which, for example, a NAND-type flash memory or a memory controller which controls the NAND-type flash memory is formed.

The semiconductor package20has a first surface and a second surface, and a plurality of electrodes21of the semiconductor chip are arranged on the first surface. The semiconductor package20has, for example, a rectangular shape.

The anisotropic conductive sheet30includes a plurality of metal wires31in an insulating sheet. The metal wires31extend in a thickness direction of the sheet and are arranged substantially in parallel with each other. The anisotropic conductive sheet30has a first surface and a second surface, and has conductivity in the thickness direction of the sheet and an insulating property in a direction parallel to its surface. Details of the anisotropic conductive sheet30will be described later.

The member40is made of, for example, a resin, a connector, and other members. Details of the member40will be described later.

The semiconductor device1has the following structure. The semiconductor package20is mounted onto the substrate10. An electrode21of the semiconductor package20is opposed to an electrode11of the substrate10. The anisotropic conductive sheet30is arranged between the substrate10and the semiconductor package20.

The metal wires31in the anisotropic conductive sheet30are in contact with the electrode11of the substrate10and the electrode21of the semiconductor package20, and electrically connect the electrode11and the electrode21.

A number of suckers34are arranged on the first surface and the second surface of the anisotropic conductive sheet30. The anisotropic conductive sheet30is sucked to the first surface and the electrodes11of the substrate10, and the first surface and the electrodes21of the semiconductor package20by these suckers34. Accordingly, the anisotropic conductive sheet30fixes the semiconductor package20to the substrate10. The first surface and the second surface of the anisotropic conductive sheet30may be configured to have adhesive properties.

The electrode21of the semiconductor package20is electrically connected to the electrode11of the substrate10through the anisotropic conductive sheet30.

The member40is provided respectively between four corners (package corner) of a rectangular shape of the semiconductor package20and the substrate10. Accordingly, the member40also fixes the semiconductor package20to the substrate10.

Hereinafter, each configuration will be described in an order of the anisotropic conductive sheet30and the member40.

With reference to sectional views ofFIGS. 3 and 4, a configuration of the anisotropic conductive sheet30included in the semiconductor device1will be described.

The anisotropic conductive sheet30is formed from, for example, an insulating sheet (for example, silicon rubber). The plurality of metal wires31arranged in the sheet are arranged at equal intervals with high density in an X direction and a Y direction as shown inFIG. 3. One end and the other end of the metal wires31are exposed from a first surface32and a second surface33of the anisotropic conductive sheet30, respectively.

An arrangement pitch of the metal wires31is, for example, 20 μm to 80 μm. A line width W of the metal wires31is, for example, 20 μm to 30 μm. For example, a gold-plated metal, iron, aluminum, gold, or the like is used for the metal wires31.

The metal wires31are inclined with respect to the thickness direction (Z direction) of the anisotropic conductive sheet30. Accordingly, it is possible to prevent any trouble that the metal wires31destroy an insulating material such as, when the anisotropic conductive sheet30is pressurized, the metal wires31moves so as to be inclined in one direction and the metal wires31are inclined or bent in an unfixed direction.

A plurality of minute suckers34are arranged on the first surface32and the second surface33of the anisotropic conductive sheet30, as shown inFIG. 4. The metal wires31are omitted inFIG. 4. About ten thousand of the suckers34are arranged in around, for example, 1 cm2. A diameter R of the sucker34is about, for example, 50 μm to 60 μm. A size of the sucker34is less than a size of the electrode11,21. Furthermore, an arrangement pitch of the suckers34is larger than the arrangement pitch of the metal wires31. In other words, the arrangement pitch of the metal wires31is smaller than the arrangement pitch of the suckers34.

The sucker34of the anisotropic conductive sheet30has a function of being sucked onto each of the first surface and the electrode11of the substrate10, and the first surface and the electrode21of the semiconductor package20. Specifically, the anisotropic conductive sheet30is interposed between the substrate10and the semiconductor package20, pressure is applied thereto to press the sucker34to the substrate10and the semiconductor package20, and thereby air exits from the sucker34. Accordingly, the inside of the sucker34becomes substantially a vacuum state, respectively, and through vacuum the anisotropic conductive sheet30is adhered to and in close contact with the substrate10and the semiconductor package20.

It is described as an example that the sucker34is arranged on the first surface and the second surface of the anisotropic conductive sheet30, but the sucker34may be arranged on only one of the first surface and the second surface of the anisotropic conductive sheet30. In this case, a surface on which the sucker is not arranged may be configured to have adhesive properties.

With reference toFIGS. 1 and 2, a configuration of the member40included in the semiconductor device1will be described.

A resin (for example, epoxy resin, and the like) is used for the member40. One member40is provided on, for example, each corner of the semiconductor package20. However, the number of the members40is not limited to four, and any number, for example, two or six members may be provided.

With reference toFIGS. 5 to 7, other configurations of the member included in the semiconductor device1will be described.

As shown inFIG. 5, a pin-shaped connector41may be used as the member40. When using the connector41, a through-hole22is provided in the semiconductor package20, and a connection portion12is provided in the substrate10. The connector41is inserted into the through-hole22of the semiconductor package20, and is connected to the connection portion12of the substrate10by threaded engagement, press fit, and other well-known connecting methods. Accordingly, the connector41fixes the semiconductor package20onto the substrate10.

Moreover, a method of mechanically holding the anisotropic conductive sheet30on the member40is shown inFIGS. 6 and 7. In this method, wires, pins or staples42, or the like may be used. When using the staples42, the anisotropic conductive sheet30is formed to be larger than the semiconductor package20in a plan view. The staples42are attached to the four corners of the anisotropic conductive sheet30and the substrate10. Accordingly, the staples42fix the anisotropic conductive sheet30onto the substrate10.

[2] Other Configurations of the Semiconductor Device

With reference toFIG. 8, other configuration examples of the semiconductor device according to the embodiment will be described. By using a substrate10A which is capable of double-sided mounting, it is possible to mount semiconductor packages20A and20B onto both surfaces of the substrate10A, respectively.

The semiconductor device2includes the substrate10A, the two semiconductor packages20A and20B, two anisotropic conductive sheets30A and30B, and members40A and40B.

The substrate10A is a wiring board on which circuit wiring is formed on the insulating substrate, and is, for example, a double-sided printed wiring board, or the like. When necessary, a multi-layer wiring board is used for the substrate10A. The substrate10A has a first surface and a second surface. A plurality of electrodes11A and12A are arranged on the first surface of the substrate10A. A plurality of electrodes11B and12B are arranged on the second surface of the substrate10B. Wirings13A and13B are arranged on a wiring layer in the substrate10A. Furthermore, the through-hole14and the like which electrically connect the electrode11A and the electrode11B are formed in the substrate10A.

The semiconductor package20A has a first surface and a second surface, and a plurality of electrodes21A of the packaged semiconductor chip are arranged on the first surface. The semiconductor package20B has a first surface and a second surface, and a plurality of electrodes21B of the packaged semiconductor chip are arranged on the first surface. For example, the semiconductor package20A includes a NAND-type flash memory, and the semiconductor package20B includes a memory controller that controls the NAND-type flash memory. The other configurations of the semiconductor packages20A and20B are the same as that of the semiconductor package20described above.

A configuration of the anisotropic conductive sheets30A and30B, and the members40A and40B is the same as a configuration of the anisotropic conductive sheet30and the member40described above, respectively.

The semiconductor device2has a structure as follows.

The semiconductor package20A is mounted onto the first surface of the substrate10A. The electrode21A of the semiconductor package20A is opposed to the electrode11A of the substrate10A. The anisotropic conductive sheet30A is arranged between the substrate10A and the semiconductor package20A.

The semiconductor package20B is mounted onto the second surface of the substrate10A. The electrode21B of the semiconductor package20B is opposed to the electrode11B of the substrate10A. The anisotropic conductive sheet30B is arranged between the substrate10A and the semiconductor package20B.

The suckers34are arranged on the first surface and the second surface of the anisotropic conductive sheet30A. Using these suckers34, the anisotropic conductive sheet30A is sucked onto the first surface and the electrode11A of the substrate10A, and the first surface and the electrode21A of the semiconductor package20A, respectively. Accordingly, the anisotropic conductive sheet30A fixes the semiconductor package20A onto the substrate10A.

In the same manner, the suckers are arranged on the first surface and the second surface of the anisotropic conductive sheet30B. Using these suckers, the anisotropic conductive sheet30B is sucked onto the second surface and the electrode11B of the substrate10A, and the first surface and the electrode21B of the semiconductor package20B, respectively. Accordingly, the anisotropic conductive sheet30B fixes the semiconductor package20B onto the substrate10A. The first surfaces and the second surfaces of the anisotropic conductive sheets30A and30B may be configured to have adhesive properties.

The electrode21A of the semiconductor package20A is electrically connected to the electrode11A of the substrate10A through the anisotropic conductive sheet30A. The electrode21B of the semiconductor package20B is connected to the electrode11B of the substrate10A through the anisotropic conductive sheet30B.

The electrode12A on the first surface of the substrate10A is electrically connected to the electrode11A through the wiring13A and a through-hole14A. The electrode12B on the second surface of the substrate10A is electrically connected to the electrode11B through the wiring13B and a through-hole14B. The electrodes12A and12B are used in connection with, for example, an external circuit.

In addition, the through-hole14formed in the substrate10A is electrically connected between the electrode11A and the electrode11B. Accordingly, an electrical connection between the electrode21A of the semiconductor package20A and the electrode21B of the semiconductor package20B may be achieved.

Moreover, the members40A are provided between four corners of a rectangular shape of the semiconductor package20A and the substrate10A, respectively. Accordingly, the members40A fix the semiconductor package20A onto the substrate10A.

In the same manner, the members40B are provided between four corners of a rectangular shape of the semiconductor package20B and the electrode10A, respectively. Accordingly, the members40B fix the semiconductor package20B onto the substrate10A.

[3] Effects of the Embodiment

With the semiconductor devices1and2according to the embodiment, it is possible to improve the mounting reliability of a semiconductor package onto a substrate.

A comparative example will be described so as to facilitate understanding of the effects.

For example, as an anisotropic conductive member which electrically connects a semiconductor package and a substrate, an anisotropic conductive film (ACF), an anisotropic conductive paste (ACP), an anisotropic conductive rubber, and the like are known.

However, the anisotropic conductive film and the anisotropic conductive paste have a concern of a leak that generated between the adjacent electrode and thereof, and detachment is difficult due to strong adhesion force (adhesive force). The anisotropic conductive rubber does not have adhesion force, and needs mechanical pressurization. In mounting by a general solder ball, heat stress is caused by soldering in a reflow, and detachment is difficult.

In contrast, the semiconductor devices1and2of the embodiment have a plurality of minute suckers provided in the first surface and the second surface of the anisotropic conductive sheet. The anisotropic conductive sheet is sucked onto the semiconductor package and the substrate using the suckers, and fixes the semiconductor package into the substrate. Therefore, since the anisotropic conductive sheet itself is in close contact with the semiconductor package and the substrate, there is no need to be pressurized from the outside.

Furthermore, metal wires are arranged in the anisotropic conductive sheet, and an end of the metal wires protrudes from a surface (the first surface and the second surface) of the sheet. The metal wires in the anisotropic conductive sheet are electrically connected between the electrode of the semiconductor package and the electrode of the substrate. Since the metal wires are arranged at equal intervals in an insulating sheet, it is possible to hold insulation between adjacent metal wires (between electrodes).

In addition, it is possible to increase connection strength and connection stability between the semiconductor package and the substrate by providing the member between the four corners of the semiconductor package and the substrate. Furthermore, the anisotropic conductive sheet has adhesion in the first surface and the second surface, such that it is possible to improve adhesion force between the semiconductor package and the substrate, and the anisotropic conductive sheet.

In addition, the members40,40A, and40B, the connector41, and the staples42have a function as a buffer material against pressure or impact from the outside. That is, when receiving pressure or impact from the outside, the members receive the power, whereby the power to be received by the anisotropic conductive sheet is relaxed. Moreover, since the anisotropic conductive sheet is in surface contact with the substrate and the semiconductor package, the anisotropic conductive sheet also functions as a buffer material against the pressure or the impact from the outside. That is, the anisotropic conductive sheet serves also as an underfill, such that the anisotropic conductive sheet becomes a buffer material of an external impact or thermal stress, and plays a role to improve the mounting reliability.

Since the anisotropic conductive sheet is sucked (or further adhesive when having adhesion) by a sucker, it is possible to repair the semiconductor device by removing the semiconductor package from the substrate without heating or the like.

With the above configuration, in the mounting of the semiconductor package onto the substrate, it is possible to improve mounting reliability which includes electrical connection between electrodes, and holding of connection strength between the substrate and the semiconductor package.

In the semiconductor device2according to the embodiment, it is possible to mount a plurality of semiconductor packages onto both surfaces (the first surface and the second surface) of the substrate using the anisotropic conductive sheet. Since the plurality of semiconductor packages can be mounted onto the both surfaces of the substrate, it is possible to reduce a mounting area.

Moreover, it is possible to reduce wiring resistance between the semiconductor packages compared to when mounting the plurality of semiconductor packages on one surface of the substrate. Furthermore, it is possible to reduce manufacturing process by mounting the plurality of semiconductor packages onto the both surfaces of the substrate at the same time.

In the semiconductor device2, it is described as an example that one semiconductor package is mounted onto the first surface and the second surface of the substrate, respectively, but the invention is not limited thereto, and a plurality of semiconductor packages can be mounted onto the first surface or the second surface, respectively.

In addition, mounting by the anisotropic conductive sheet used in the embodiment can be replaced with mounting by solder.