Semiconductor relay

Abstract

An output circuit (OPC) of a semiconductor relay (1) has a first MOSFET element (3) and a second MOSFET element (4), and controls signal transmission between a first output terminal (8) and a second output terminal (9) on the basis of a second drive signal output from a drive circuit (DRC). A first metal bump (13A) is provided on a first source electrode (3e) of the first MOSFET element (3), and a second metal bump (14A) is provided on a second source electrode (4e) of the second MOSFET element (4). The front surface (12a) of a connection conductor (12) is a first metal layer (12c), and the rear surface (12b) thereof is a second metal layer (12d). Each of the first metal bump (13A) and the second metal bump (14A) is bonded to the first metal layer (12c). The flatness of the front surface (12a) of the connection conductor (12) is higher than the flatness of the rear surface (12b) of the connection conductor (12).

Description

Semiconductor relay

[0001] The present disclosure relates to a semiconductor relay.

[0002] Conventionally, semiconductor relays, which are also called MOSFET (Metal-Oxide-Semiconductor Field Effect Transistor) output photocouplers or optical MOSFETs, have been known as signal transmission means. In such semiconductor relays, an increase in insertion loss has become a problem along with the higher frequency of transmission signals. More specifically, when the inductance component of an output circuit in a semiconductor relay is large, it has been observed that the insertion loss tends to increase.

[0003] In order to solve this problem, configurations disclosed in, for example, Patent Documents 1 and 2 have been proposed. For example, Patent Document 1 discloses an optically coupled semiconductor relay in which a connection conductor is provided on the back surface of a light-receiving driving element, and the light-receiving driving element is arranged so as to cover the respective surfaces of two MOSFET elements. Further, a first connection body and a second connection body, which are conductors, are respectively provided between the connection conductor and the source electrodes. The two source electrodes are electrically connected to each other via the connection conductor, the first connection body, and the second connection body. In addition, Patent Document 2 discloses an optically coupled semiconductor relay in which the source electrodes of two MOSFET elements constituting an output circuit are connected to each other by a plated wiring. In either case, since the width of the wiring connecting the source electrodes of the two MOSFET elements can be increased, the inductance component of the output circuit in the semiconductor relay, and consequently the insertion loss, can be reduced.

[0004] International Publication No. 2024 / 190452; Japanese Unexamined Patent Application Publication No. 2002-359392

[0005] In the conventional configuration disclosed in Patent Document 1, the connecting conductor is a layered or sheet-like conductive material. In this case, the connection resistance between the first or second connector and the connecting conductor may become high. For example, if the resistivity of the first or second connector and the connecting conductor differs significantly, the aforementioned connection resistance may become high. Furthermore, depending on the materials of the first or second connector and the connecting conductor, the interfacial resistance between the first or second connector and the connecting conductor may become high. These tendencies become more pronounced when the connecting conductor is a conductive die attach film mixed with a conductive filler.

[0006] Furthermore, in cases where the connecting conductor is a flexible conductive sheet, the connecting conductor may deform due to prolonged use or external environmental factors such as temperature changes in which the semiconductor relay is located. Such deformation may cause the connecting conductor to come into contact with the MOSFET element of the output circuit, potentially adversely affecting the output characteristics of the MOSFET element.

[0007] Furthermore, in the configuration disclosed in Patent Document 2, there is a risk that the plated wiring may deform and come into contact with the MOSFET element. Also, Patent Document 2 does not disclose how the source electrode and the plated wiring are connected, and under certain conditions, the connection resistance between the source electrode and the plated wiring may become high.

[0008] The semiconductor relay according to this disclosure comprises at least an input circuit, a drive circuit, an output circuit, and a plate-shaped connecting conductor having a laminated structure of a first metal layer and a second metal layer. The input circuit and the output circuit are electrically insulated from each other. The input circuit has a first input terminal, a second input terminal, and an input element, and outputs a first drive signal to the drive circuit based on an input signal input between the first input terminal and the second input terminal. The drive circuit outputs a second drive signal to the output circuit based on the first drive signal. The output circuit has at least a first output terminal, a second output terminal, and an output element, and either makes the first output terminal and the second output terminal conductive or non-conductive based on the second drive signal. The output element has a first MOSFET element and a second MOSFET element, each electrically connected to the drive circuit. The first MOSFET element has a first gate electrode and a first source electrode formed on its surface, and a first connector is provided on the surface of the first source electrode. The second MOSFET element has a second gate electrode and a second source electrode formed on its surface, and a second connector is provided on the surface of the second source electrode. The first connector and the second connector are each metal bumps. The surface of the connecting conductor is formed of the first metal layer, and the back surface of the connecting conductor, which is the opposite surface of the connecting conductor, is formed of the second metal layer. The first connector and the second connector are each joined to the surface of the first metal layer, which is the surface of the connecting conductor. The flatness of the surface of the first metal layer is higher than the flatness of the back surface of the second metal layer, which is the back surface of the connecting conductor. The first source electrode and the second source electrode are electrically connected to each other via the first connector, the connecting conductor, and the second connector.

[0009] According to this disclosure, in the connection between the connecting conductor and the connector that connects the source electrodes of the output element, the connection resistance can be reduced and the connection reliability can be improved.

[0010] This is a perspective view of a semiconductor relay according to Embodiment 1. This is a view of the semiconductor relay from direction A shown in Figure 1. This is a partially exploded perspective view of the semiconductor relay. This is a perspective view of the light-emitting element. This is a perspective view of the light-receiving driving element. This is a perspective view of the first MOSFET element. This is a perspective view of the connecting conductor. This is a plan view of the connecting conductor. This is a view of the first and second MOSFET elements and the connecting conductor inside the semiconductor relay from direction B shown in Figure 1. This is a schematic cross-sectional view of the connecting conductor connected to the source electrode. This is an equivalent circuit diagram of the semiconductor relay according to Embodiment 1. This is a diagram corresponding to Figure 2 of the semiconductor relay according to Modification 1. This is a diagram corresponding to Figure 2 of the semiconductor relay according to Modification 2. This is an equivalent circuit diagram of the semiconductor relay according to Embodiment 2. This is a perspective view of the semiconductor relay. This is a view of the semiconductor relay from above. This is a view of the semiconductor relay from direction C shown in Figure 14.

[0011] Embodiments of the present disclosure will be described below with reference to the drawings. The following description of preferred embodiments is illustrative in nature and is not intended to limit the present disclosure, its applications, or its uses.

[0012] (Embodiment 1) [Configuration of Semiconductor Relay] Figure 1 shows a perspective view of the semiconductor relay according to this embodiment, and Figure 2 shows a side view of the semiconductor relay as seen from direction A shown in Figure 1. Figure 3 is a partially exploded perspective view of the semiconductor relay. Figure 4 is a perspective view of the light-emitting element. Figure 5 is a perspective view of the light-receiving driving element. Figure 6 is a perspective view of the first MOSFET element.

[0013] For the sake of clarity, in Figures 1 and 2, the outlines of the housing 10 and the light-shielding resin 10a and light-transmitting resin 10b that constitute it are shown with dashed lines. Also, in Figures 1 to 6, the shapes of each component are simplified. For example, the shapes of the first metal bump 13A and the second metal bump 14A shown in Figure 3 differ from the actual shapes.

[0014] In the following explanation, the direction perpendicular to the surface 12a of the connecting conductor 12 (see Figures 3 and 8) may be referred to as the first direction. Also, in this embodiment, the X direction is the direction in which the light-emitting element 2 and the light-receiving driving element 5 face each other, and is also the first direction. The direction in which the first output terminal 8 and the second output terminal 9 are aligned may be referred to as the Y direction. The Y direction is also the direction in which the first input terminal 6 and the second input terminal 7 are aligned. The direction perpendicular to both the X direction and the Y direction may be referred to as the Z direction.

[0015] In this specification, "orthogonal" or "parallel" means that the processing tolerances and manufacturing tolerances of each component constituting the semiconductor relay 1, as well as the assembly tolerances between the components, are orthogonal or parallel. It does not mean that the comparison objects themselves are orthogonal or parallel in a strict sense.

[0016] In this embodiment, the X direction is also the direction in which the light-receiving driving element 5, the first MOSFET element 3, and the second MOSFET element 4 are aligned. In the Z direction, the side where the first MOSFET mounting section 82 is located may be referred to as "up" or "upper," and the side where the first output side external terminal section 81 is located may be referred to as "down" or "lower." In this specification, the terms "up" and "down" are purely relative and do not, for example, mean "up" or "down" along the vertical direction.

[0017] Furthermore, the terms "front" and "back" in this specification are defined as follows. First, in the light-emitting element 2, the surface on which the anode electrode 2c is formed is the front surface 2a, and the surface on which the cathode electrode 2d is formed is the back surface 2b (see Figure 4). In the light-receiving driving element 5, the surface on which the source electrode 5c and drain electrode 5d are formed is the front surface 5a, and the surface opposite to the front surface 5a is the back surface 5b. In the first MOSFET element 3 and the second MOSFET element 4, the surfaces on which the first and second gate electrodes 3d and 4d and the first and second source electrodes 3e and 4e are formed are the front surfaces 3a and 4a, respectively, and the surfaces opposite to the front surfaces 3a and 4a are the back surfaces 3b and 4b. Also, in the first and second source electrodes 3e and 4e, the surfaces on which the first connector 13 and the second connector 14 are arranged are called the front surfaces.

[0018] Furthermore, in the connecting conductor 12, the surface that is joined to the respective ends of the first connector 13 and the second connector 14 is called the surface 12a, and the surface opposite to the surface 12a is called the back surface 12b. Note that the surface 12a is the surface of the first metal layer 12c, which will be described later, and the back surface 12b is the back surface of the second metal layer 12d (see Figures 7A to 9). Also, in the first metal layer 12c, the surface that is in contact with the surface 12d1 of the second metal layer 12d is the back surface 12c1.

[0019] For each of the first input terminal 6, second input terminal 7, first output terminal 8, and second output terminal 9, the side on which the element is mounted or the side to which the wire 11 is connected is designated as the front surface 6a, 7a, 8a, 9a, and the side facing the front surfaces 6a, 7a, 8a, 9a is designated as the back surface 6b, 7b, 8b, 9b.

[0020] As shown in Figures 1 and 2, the semiconductor relay 1 comprises a light-emitting element 2, a light-receiving driving element 5, a first MOSFET element 3, and a second MOSFET element 4. The semiconductor relay 1 also comprises a first input terminal 6, a second input terminal 7, a first output terminal 8, a second output terminal 9, and a housing 10.

[0021] The light-emitting element 2 is a known LED (Light Emitting Diode) element. As shown in Figure 4, an anode electrode 2c is formed on the surface 2a of the light-emitting element, and a cathode electrode 2d is formed on the back surface 2b. The cathode electrode 2d is connected and fixed to the surface 7a of the light-emitting element mounting portion 72 of the second input terminal 7 via a conductive adhesive (not shown), such as silver paste. In other words, the cathode electrode 2d is electrically connected to the second input terminal 7.

[0022] The light-receiving driving element 5 includes a light-receiving element 51 and a control circuit 52 (see Figure 10). The light-receiving element 51 is, for example, made up of an array of known photodiodes. As shown in Figures 3 and 5, a source electrode 5c and a drain electrode 5d are formed on the surface 5a of the light-receiving driving element 5. The drain electrode 5d is provided at two locations on the surface 5a that are spaced apart from each other. Although the light-receiving element 51 is also formed on the surface 5a of the light-receiving driving element 5, it is omitted from the illustration for the sake of explanation.

[0023] Furthermore, as shown in Figures 1 and 2, a connecting conductor 12 is arranged on the back surface 5b of the light-receiving driving element 5. As shown in Figures 3, 7A, and 7B, the connecting conductor 12 is a flat conductive member. The shape and function of the connecting conductor 12 will be explained later.

[0024] As shown in Figures 1-3, the source electrode 5c of the light-receiving driving element 5 and the first source electrode 3e of the first MOSFET element 3 are electrically connected via a wire 11. One of the two drain electrodes 5d, 5d of the light-receiving driving element 5 is electrically connected to the first gate electrode 3d of the first MOSFET element 3 via a wire 11. The other of the two drain electrodes 5d, 5d is electrically connected to the second gate electrode 4d of the second MOSFET element 4 via a wire 11.

[0025] The first MOSFET element 3 is formed by forming a known vertical MOSFET on a semiconductor substrate. The first MOSFET element 3 is usually composed of multiple vertical MOSFETs connected in series or in parallel. However, it may also be a single vertical MOSFET. As shown in Figure 6, a first gate electrode 3d and a first source electrode 3e are formed on the surface 3a of the first MOSFET element 3, and a first drain electrode 3f is formed on the back surface 3b. The first drain electrode 3f is formed over the entire surface of the back surface 3b of the first MOSFET element 3.

[0026] As shown in Figure 6, the first source electrode 3e has a first electrode body portion 3e1 and a first enlarged electrode portion 3e2. As shown in Figures 1 to 3, inside the semiconductor relay 1, the longitudinal direction of the first electrode body portion 3e1 is the Z direction. The first enlarged electrode portion 3e2 is formed continuously with the first electrode body portion 3e1. Also, when viewed along the X direction, the first electrode body portion 3e1 has a portion that overlaps with the light-receiving driving element 5 (see Figures 1 to 3).

[0027] Furthermore, the second MOSFET element 4 has the same structure as the first MOSFET element 3 (see Figure 6). Therefore, the arrangement and shape of the second gate electrode 4d, the second source electrode 4e, and the second drain electrode 4f are the same as those of the first MOSFET element 3. In other words, the second source electrode 4e also has a second electrode body portion 4e1 and a second expanded electrode portion 4e2, and their shapes and arrangements are the same as those of the first electrode body portion 3e1 and the first expanded electrode portion 3e2, respectively. For example, when viewed along the X direction, the second electrode body portion 4e1 has a portion that overlaps with the light-receiving driving element 5 (see Figures 1-3).

[0028] Furthermore, as is clear from Figure 3, a first connector 13 is provided on the surface of the first electrode body portion 3e1 of the first source electrode 3e. A second connector 14 is provided on the surface of the second electrode body portion 4e1 of the second source electrode 4e.

[0029] Furthermore, the portions of the surface 3a of the first MOSFET element and the surface 4a of the first MOSFET element 4 on which the light-receiving driving element 5 is mounted are sometimes referred to as the first mounting portion 3a1 and the second mounting portion 4a1, respectively, while the portions on which the light-receiving driving element 5 is not mounted are sometimes referred to as the first non-mounting portion 3a2 and the second non-mounting portion 4a2, respectively.

[0030] The first mounting portion 3a1 is provided with the first electrode body portion 3e1 of the first source electrode 3e, and the second mounting portion 4a1 is provided with the second electrode body portion 4e1 of the second source electrode 4e. The first non-mounting portion 3a2 is provided with the first enlarged electrode portion 3e2 and the first gate electrode portion 3d of the first source electrode 3e, and the second mounting portion 4a1 is provided with the second enlarged electrode portion 4e2 and the second gate electrode portion 4d of the second source electrode 4e.

[0031] Furthermore, as shown in Figure 2, the first drain electrode 3f of the first MOSFET element 3 is fixed to the surface 8a of the first MOSFET mounting portion 82 of the first output terminal 8 with a conductive adhesive such as silver paste (not shown). Although not shown, similar to the first drain electrode 3f, the second drain electrode 4f of the second MOSFET element 4 is fixed to the surface 9a of the second MOSFET mounting portion 92 of the second output terminal 9 with a conductive adhesive.

[0032] As shown in Figure 3, the first connector 13 is composed of a plurality of first metal bumps 13A, and the second connector 14 is composed of a plurality of second metal bumps 14A. In this case, a plurality of first metal bumps 13A are formed on the surface of the first electrode body portion 3e1 of the first source electrode 3e, and the first connector 13 is provided. A plurality of second metal bumps 14A are formed on the surface of the second electrode body portion 4e1 of the second source electrode 4e.

[0033] The first input terminal 6 and the second input terminal 7 are conductive members obtained by processing a metal plate. For example, the material of the metal plate is copper. Alternatively, another metal film, such as a nickel-containing metal film (not shown), may be plated onto the surface of the copper plate to form a metal plate. Furthermore, the material of the metal film is not particularly limited.

[0034] In this embodiment, components such as the light-emitting element 2, the first MOSFET element 3, the first MOSFET element 4, and the light-receiving driving element 5 are mounted on a lead frame (not shown) made of a metal plate, and the lead frame and each component are resin-sealed with a light-shielding resin 10a. The semiconductor relay 1 is obtained such that the first input terminal 6, the second input terminal 7, the first output terminal 8, and the second output terminal 9 are formed by a part of the lead frame. In addition, a light-transmitting resin 10b is filled between the light-receiving driving element 5 and the light-emitting element 2.

[0035] The first input terminal 6 has a first input side external terminal portion 61, a wire connection portion 62, and a branch portion 63. The second input terminal 7 has a second input side external terminal portion 71, a light-emitting element mounting portion 72, and branch portions 73a to 73c. ​​In the semiconductor relay 1, the first input terminal 6 is arranged side by side with the second input terminal 7 in the Y direction, while being spaced apart from the second input terminal 7.

[0036] As shown in Figures 1 and 2, the first input terminal 6 and the second input terminal 7 each extend downward along the Z direction from one end located inside the housing 10, are bent near the bottom surface of the housing 10, and the other end extends along the X direction from the side surface of the housing 10 and further protrudes outside the housing 10. In each of the first input terminal 6 and the second input terminal 7, the parts that protrude outside the housing 10 are the first and second input side external terminal portions 61 and 71.

[0037] At the first input terminal 6, one end of the wire 11 is connected to the surface of the wire connection portion 62, and the other end of the wire 11 is connected to the anode electrode 2c of the light-emitting element 2. The branch portion 63 protrudes from the wire connection portion 62 in the Y direction and on the opposite side from the second input terminal 7. The tip of the branch portion 63 is exposed on the side surface of the housing 10. The branch portion 63 is a part of the aforementioned lead frame that remained at the first input terminal 6 when the semiconductor relay 1 was disconnected.

[0038] As described above, the light-emitting element 2 is placed on the surface 7a of the light-emitting element mounting portion 72 of the second input terminal 7. Also, the branch portions 73a to 73c are, like the branch portion 63, parts of the lead frame that remained on the second input terminal 7 when the semiconductor relay 1 was disconnected. The tips of the branch portions 73a to 73c are exposed on the side surface of the housing 10.

[0039] The first output terminal 8 has a first output side external terminal section 81, a first MOSFET mounting section 82, and a branching section 83. The second output terminal 9 has a second output side external terminal section 91, a second MOSFET mounting section 92, and a branching section 93.

[0040] As shown in Figure 2, the first output terminal 8 and the second output terminal 9 each extend downward along the Z direction from one end located inside the housing 10, are bent near the bottom surface of the housing 10, and the other end extends along the Y direction from the side surface of the housing 10 and further protrudes outside the housing 10. In the first output terminal 8, the portion that protrudes outside the housing 10 is the first output side external terminal portion 81. In the second output terminal 9, the portion that protrudes outside the housing 10 is the second output side external terminal portion 91.

[0041] The first MOSFET mounting section 82 and the second MOSFET mounting section 92 are each located inside the housing 10. The first MOSFET element 3 is mounted on the surface 8a of the first MOSFET mounting section 82, and the second MOSFET element 4 is mounted on the surface 9a of the second MOSFET mounting section 92. The first output terminal 8 is positioned alongside the second output terminal 9 in the Y direction, while being spaced apart from the second output terminal 9.

[0042] As shown in FIG. 2, the first MOSFET mounting portion 82 and the second MOSFET mounting portion 92 face each other in the X direction at a predetermined distance from the light emitting element mounting portion 72 of the second input terminal 7.

[0043] Further, when viewed from the Z direction, the first output-side external terminal portion 81 faces the first input-side external terminal portion 61 of the first input terminal 6 in the Y direction. The second output-side external terminal portion 91 faces the second input-side external terminal portion 71 of the second input terminal 7 in the Y direction.

[0044] The housing 10 encapsulates the first input terminal 6, the second input terminal 7, the first output terminal 8, and the second output terminal 9, and fixes their respective positions. It goes without saying that the light emitting element 2 mounted on the second input terminal 7, the first MOSFET element 3 mounted on the first output terminal 8, the second MOSFET element 4 mounted on the second output terminal 9, and further the light receiving driving element 5 are also encapsulated by the housing 10 and their respective positions are fixed. As described above, the first output-side external terminal portion 81, the second output-side external terminal portion 91, the first input-side external terminal portion 61, and the second input-side external terminal portion 71 each protrude to the outside of the housing 10.

[0045] As shown in FIG. 2, the housing 10 is composed of an insulating light-shielding resin 10a and a translucent resin 10b. The light-shielding resin 10a is, for example, an epoxy resin containing a black pigment. However, the material is not particularly limited thereto, and any material that shields light may be used. The translucent resin 10b is provided between the light receiving driving element 5 and the light emitting element 2, and is encapsulated by the light-shielding resin 10a. The translucent resin 10b is, for example, a transparent silicone resin. However, it is not particularly limited thereto, and any insulating resin that is transparent to at least the light emitted from the light emitting element 2 may be used. The translucent resin 10b constitutes an optical coupling portion that optically couples the light receiving element 51 of the light receiving driving element 5 and the light emitting element 2.

[0046] Further, the first input terminal 6, the second input terminal 7, the first output terminal 8, and the second output terminal 9 are electrically insulated from each other by the housing 10. Furthermore, the light-emitting element 2 and the light-receiving driving element 5 are optically coupled. That is, the semiconductor relay 1 is an input / output insulated semiconductor relay that turns an output signal on and off via optical coupling in a state where an input circuit IPC and an output circuit OPC (both refer to FIG. 10) are electrically insulated.

[0047] [Connection Structure Between Connecting Conductor and First and Second Connecting Bodies] FIG. 7A is a perspective view of the connecting conductor. FIG. 7B is a plan view of the connecting conductor. FIG. 8 is a view of the first and second MOSFET elements inside the semiconductor relay and the connecting conductor as viewed from direction B shown in FIG. 1. FIG. 9 is a schematic cross-sectional view of the connecting conductor connected to a source electrode. For convenience of description, the connecting conductor 12 is shown by a broken line in FIG. 8. In addition, in FIGS. 7A, 7B, and 9, the shapes of respective components are illustrated in a simplified manner. For example, the shapes of the first metal bump 13A and the second metal bump 14A shown in FIG. 9 are different from actual shapes.

[0048] The connecting conductor 12 is obtained, for example, by processing a lead frame made of nickel or copper. In addition, as shown in FIGS. 7B and 9, the connecting conductor 12 includes first to third connecting conductor portions 121 to 123. The first connecting conductor portion 121 is a part of the connecting conductor 12 that is disposed between the light-receiving driving element 5 and the first electrode main body portion 3e1 of the first source electrode 3e, and is electrically connected to the first connecting body 13. The second connecting conductor portion 122 is a part of the connecting conductor 12 that is disposed between the light-receiving driving element 5 and the second electrode main body portion 4e1 of the second source electrode 4e, and is electrically connected to the second connecting body 14. The third connecting conductor portion 123 is a part of the connecting conductor 12 that electrically connects the first connecting conductor portion 121 and the second connecting conductor portion 122, and overlaps the light-receiving driving element 5 when viewed along the X direction.

[0049] As shown in Figure 8, the first connector 13, that is, six first metal bumps 13A, are provided on the surface of the first electrode body 3e1 of the first source electrode 3e. More specifically, three of the six first metal bumps 13A are arranged in a row with the same spacing P in the Z direction, and the remaining three first metal bumps 13A are also arranged in a row with the same spacing P in the Z direction. However, the two rows of first metal bumps 13A aligned in the Y direction are provided on the surface of the first electrode body 3e1 with a shift of P / 2 in the Z direction.

[0050] Similarly, the second connector 14, that is, the six second metal bumps 14A, are provided on the surface of the second electrode body portion 4e1 of the second source electrode 4e. More specifically, three of the six second metal bumps 14A are arranged in a row with the same spacing P in the Z direction, and the remaining three second metal bumps 14A are also arranged in a row with the same spacing P in the Z direction. However, the two rows of second metal bumps 14A aligned in the Y direction are provided on the surface of the second electrode body portion 4e1 with a shift of P / 2 in the Z direction.

[0051] Furthermore, the connecting conductor 12 is attached to the first connector 13 and the second connector 14 such that the center line CL2 of the connecting conductor 12 in the Y direction coincides with the respective center lines of the first connector 13 and the second connector 14 in the Y direction. Also, when viewed along the X direction, the first connector 13 and the second connector 14 are arranged symmetrically with respect to the center line CL1 of the housing 10 in the Z direction.

[0052] The number of first metal bumps 13A and second metal bumps 14A is not particularly limited to the example shown in Figure 8 and can be changed as appropriate. However, when two or more first metal bumps 13A are arranged, it is preferable that they be arranged in two rows in the Y direction and at different positions along the Z direction. Also, when three or more first metal bumps 13A are arranged, it is preferable that they be arranged at the same intervals along the Z direction. These also apply to the second metal bumps 14A. However, even in these cases, the two rows of first metal bumps 13A aligned in the Y direction are provided on the surface of the first electrode body 3e1 with a shift of P / 2 in the Z direction.

[0053] Furthermore, as shown in Figure 8, when the width of the first connector 13 and the second connector 14 along the Z direction is W2, and the width of the connecting conductor 12 along the Z direction is W1, it is preferable that the relationship shown in equation (1) is satisfied.

[0054] 0.5 × W1 ≤ W2 ≤ W1 ... (1) Also, the width of the connecting conductor 12 in the Y direction is wider than the width of the first connecting body 13 and the second connecting body 14 along the Y direction.

[0055] As explained above, by defining the arrangement and size of the first metal bump 13A, the second metal bump 14A, and the connecting conductor 12, the tilt of the connecting conductor 12 can be suppressed when attaching the connecting conductor 12 to the first connector 13 and the second connector 14. In addition, it is possible to prevent the connecting conductor 12 from contacting the first MOSFET element 3 and / or the second MOSFET element 4, thereby preventing short-circuit failures.

[0056] In this embodiment, the first metal bump 13A and the second metal bump 14A are gold bumps and stud bumps. However, the material of the first metal bump 13A and the second metal bump 14A is not particularly limited. Also, depending on the size of the first source electrode 3e and the second source electrode 4e, the first connector 13 may be one first metal bump 13A and the second connector 14 may be one second metal bump 14A.

[0057] Furthermore, as shown in Figures 7A, 7B and 9, the connecting conductor 12 is a flat metal conductor formed by laminating a first metal layer 12c and a second metal layer 12d. The first metal layer 12c is made of the same metal as the first metal bump 13A and the second metal bump 14A. In other words, the first metal layer 12c in this embodiment is made of gold. The second metal layer 12d is made of nickel. However, the second metal layer 12d may be made of another metal, such as copper.

[0058] Furthermore, in this embodiment, the second metal layer 12d is formed to have a peripheral edge 12d2 on its back side. In other words, the connecting conductor 12 is formed such that the area of ​​the back surface 12b of the second metal layer 12d is larger than the area of ​​the front surface 12d1 of the second metal layer 12d. Also, the first metal layer 12c is formed over the entire front surface 12d1 of the second metal layer 12d. Therefore, it can be said that the connecting conductor 12 is formed such that the area of ​​the back surface 12b of the second metal layer 12d is larger than the area of ​​the front surface 12a of the first metal layer 12c.

[0059] Furthermore, as shown in Figures 7A and 9, a gentle step is created in the thickness direction of the connecting conductor 12 on the back surface 12b1 surrounding the peripheral edge 12d2 of the back surface 12b of the second metal layer 12d. As is clear from this, the connecting conductor 12 is formed such that the flatness of the surface 12a of the first metal layer 12c is higher than the flatness of the back surface 12b of the second metal layer 12d. The "flatness" referred to here is the flatness defined in the Japanese Industrial Standard (JIS G 3193-2019). This standard specifies the shape, dimensions, mass and tolerances of hot-rolled steel sheets and strips, but it can conventionally be applied to sheet materials made of other materials as well. Also, when the flatness of surface A is higher than the flatness of surface B, it means that surface A is a flatter surface than surface B.

[0060] Furthermore, in the connecting conductor 12, the surface roughness of the surface 12a of the first metal layer 12c and the surface roughness of the back surface 12b of the second metal layer 12d are formed to be different from each other. The "surface roughness" referred to here is the surface roughness defined in the Japanese Industrial Standards (JIS B 0601-2001). This surface roughness is a smaller amount than the flatness mentioned above. As shown in Figure 9, the tips of the multiple first metal bumps 13A formed on the surface of the first electrode body 3e1 of the first source electrode 3e of the first MOSFET element 3 are metal-bonded to the surface 12a of the connecting conductor 12, that is, to the first metal layer 12c. Also, the tips of the multiple second metal bumps 14A formed on the surface of the second electrode body 4e1 of the second source electrode 4e of the second MOSFET element 4 are metal-bonded to the surface 12a of the connecting conductor 12, that is, to the first metal layer 12c. As a result, the first source electrode 3e of the first MOSFET element 3 and the second source electrode 4e of the second MOSFET element 4 are electrically connected via the multiple first metal bumps 13A and second metal bumps 14A and the connecting conductor 12. Furthermore, the thickness of the first metal layer 12c is set to a value necessary to ensure reliable metal bonding with the first metal bumps 13A and second metal bumps 14A.

[0061] The connecting conductor 12 and the first metal bump 13A and the second metal bump 14A are joined, for example, by the following procedure.

[0062] First, the connecting conductor 12 is moved above the first metal bump 13A on the first MOSFET element 3 and the second metal bump 14A on the second MOSFET element 4 using a suction tool (not shown). After the first metal layer 12c of the connecting conductor 12 is brought into contact with the tips of the first metal bump 13A and the second metal bump 14A, a pressurizing and heating process is performed to attach the connecting conductor 12 to the first MOSFET element 3 and the second MOSFET element 4. Next, the connecting conductor 12 is attached to the light-receiving driving element 5 so that the back surface 12b of the connecting conductor 12 is in contact with the back surface 5b of the light-receiving driving element 5.

[0063] During the pressurization and heating process, a solid-phase diffusion reaction proceeds at the interface between the first metal layer 12c and the first metal bump 13A and the second metal bump 14A, resulting in metal bonding between the first metal layer 12c and the first metal bump 13A, and between the first metal layer 12c and the second metal bump 14A.

[0064] [Circuit Configuration and Operation of Semiconductor Relay] Figure 10 is an equivalent circuit diagram of a semiconductor relay according to Embodiment 1. Note that the inductance L1 shown in Figure 8 is the parasitic inductance between the source (S) of the first MOSFET element 3 and the source (S) of the second MOSFET element 4, and is not an actual component of the semiconductor relay 1.

[0065] As shown in Figure 10, the input circuit IPC of the semiconductor relay 1 has a first input terminal 6, a second input terminal 7, and a light-emitting element 2. The output circuit OPC has a first output terminal 8, a second output terminal 9, a first MOSFET element 3, and a second MOSFET element 4. The connecting conductor 12, the first connector 13, and the second connector 14 are also included in the output circuit OPC. The drive circuit DRC has a light-receiving element 51 and a control circuit 52.

[0066] When an input signal is input between the first input terminal 6 and the second input terminal 7, the light-emitting element 2 outputs an optical signal of a predetermined wavelength. The optical signal generated by the light-emitting element 2 is the first drive signal, and the first drive signal propagates inside the light-transmitting resin 10b and is received by the light-receiving element 51.

[0067] In the light-receiving element 51, a current is generated by photoelectric conversion, and the control circuit 52 operates based on this current. A second drive signal, which is a voltage signal corresponding to the light intensity of the light-emitting element 2, is applied via the wire 11 to the first gate electrode 3d of the first MOSFET element 3 and the second gate electrode 4d of the second MOSFET element 4, respectively.

[0068] When the voltage of the second drive signal exceeds the threshold voltages of the first MOSFET element 3 and the second MOSFET element 4, the source (S)-drain (D) junctions of the first MOSFET element 3 and the source (S)-drain (D) junctions of the second MOSFET element 4 are turned ON. Furthermore, the first output terminal 8 and the second output terminal 9 become conductive through the first MOSFET element 3 and the second MOSFET element 4. As a result, a signal is transmitted between the first output terminal 8 and the second output terminal 9.

[0069] When no input signal is received between the first input terminal 6 and the second input terminal 7, the light emission from the light-emitting element 2 also stops. Accordingly, no current is generated in the light-receiving element 51, and the control circuit 52 stops.

[0070] As a result, the voltage of the second drive signal applied to the first gate electrode 3d of the first MOSFET element 3 and the second gate electrode 4d of the second MOSFET element 4 decreases. When the voltage of the second drive signal falls below the threshold voltage mentioned above, the source (S)-drain (D) junction of the first MOSFET element 3 and the source (S)-drain (D) junction of the second MOSFET element 4 are turned off. Furthermore, the connection between the first output terminal 8 and the second output terminal 9 becomes non-conductive. This interrupts signal transmission between the first output terminal 8 and the second output terminal 9.

[0071] [Effects, etc.] As described above, the semiconductor relay 1 according to this embodiment comprises at least an input circuit IPC, a drive circuit DRC, and an output circuit OPC, and the input circuit IPC and the output circuit OPC are electrically isolated from each other.

[0072] The input circuit IPC has at least a first input terminal 6, a second input terminal 7, and an input element, a light-emitting element 2. Based on the input signal input between the first input terminal 6 and the second input terminal 7, the input circuit IPC outputs an optical signal, which is a first drive signal, to the photodetector 51 of the drive circuit DRC.

[0073] The drive circuit DRC outputs a second drive signal to the output circuit OPC based on the first drive signal.

[0074] The output circuit OPC has at least a first output terminal 8, a second output terminal 9, and an output element, and based on a second drive signal, it either makes the first output terminal 8 and the second output terminal 9 conductive or non-conductive.

[0075] The output element comprises a first MOSFET element 3 and a second MOSFET element 4, both electrically connected to the drive circuit DRC.

[0076] The first MOSFET element 3 has a first gate electrode 3d and a first source electrode 3e formed on its surface 3a, and a first connector 13 is provided on the surface of the first source electrode 3e.

[0077] The second MOSFET element 4 has a second gate electrode 4d and a second source electrode 4e formed on its surface 4a, and a second connector 14 is provided on the surface of the second source electrode 4e.

[0078] The first connector 13 and the second connector 14 are each at least one metal bump.

[0079] The semiconductor relay 1 is joined to the ends of the first connector 13 and the second connector 14, and further has a plate-shaped connecting conductor 12 made of a metallic material. The connecting conductor 12 has a laminated structure of a first metal layer 12c and a second metal layer 12d, and the flatness of the surface 12a of the first metal layer 12c is higher than the flatness of the back surface 12b of the second metal layer 12d.

[0080] The first source electrode 3e and the second source electrode 4e are electrically connected via the first connector 13, the connecting conductor 12, and the second connector 14.

[0081] According to this embodiment, the bonding strength between the connecting conductor 12 and the first connector 13 and the second connector 14 can be increased by metal bonding. Furthermore, by making the flatness of the surface 12a of the first metal layer 12c higher than the flatness of the back surface 12b of the second metal layer 12d, the amount of deformation of the bumps can be made uniform when the first metal bumps 13A and the second metal bumps 14A are metal-bonded to the first metal layer 12c. As a result, the bonding between the connecting conductor 12 and the first connector 13 and the second connector 14 can be stabilized, and the bonding strength between the connecting conductor 12 and the first connector 13 and the second connector 14 can be increased. In addition, by ensuring that the connecting conductor 12 and the first connector 13 and the second connector 14 are securely connected, the connection resistance between the first source electrode 3e of the first MOSFET element 3 and the second source electrode 4e of the second MOSFET element 4 can be reduced, thereby improving connection reliability.

[0082] Furthermore, according to this embodiment, the parasitic inductance component can be reduced by connecting the first source electrode 3e of the first MOSFET element 3 and the second source electrode 4e of the second MOSFET element 4 with a connecting conductor 12. Normally, the wire diameter of the wire 11 is about 0.0 mm, while the width W1 in the Z direction of the connecting conductor 12 is several to more than 10 times larger than this value. For this reason, the inductance per unit length along the signal path inside the semiconductor relay 1 is smaller in the semiconductor relay 1 of this embodiment using the connecting conductor 12 than in the case using the wire 11.

[0083] In other words, according to this embodiment, the parasitic inductance component can be reduced, and as a result, insertion loss can be reduced. Furthermore, by reducing the inductance along the signal path, the mismatch in the characteristic impedance of the signal path can be reduced. This improves the reflection characteristics within the signal path, and consequently, insertion loss can be further reduced.

[0084] Furthermore, the connecting conductor 12 is formed such that the area of ​​the back surface 12b of the second metal layer 12d is larger than the area of ​​the front surface 12d1 of the first metal layer 12c. In this way, even when the size of the light-receiving driving element 5 is larger than the size of the first connector 13 and the second connector 14 when viewed from the X direction, the connecting conductor 12 can be securely bonded to the light-receiving driving element 5 and the connecting conductor 12, and the connecting conductor 12 can be connected to the first connector 13 and the second connector 14. From another perspective, this expands the range of size options for the light-receiving driving element 5 provided in the semiconductor relay 1.

[0085] Furthermore, the connecting conductor 12 is formed such that the area of ​​the back surface 12b of the second metal layer 12d is larger than the area of ​​the front surface 12d1 of the second metal layer 12d. The first metal layer 12c is formed on the front surface 12d1 of the second metal layer 12d, which has a smaller area. As mentioned above, if the first metal layer 12c is gold, it is possible to prevent the surface 12d1 forming the expensive first metal layer 12c from becoming unnecessarily large, thereby suppressing an increase in the manufacturing cost of the semiconductor relay 1.

[0086] Preferably, the surface roughness of the surface 12a of the first metal layer 12c is different from the surface roughness of the back surface 12b of the second metal layer 12d.

[0087] If the surface roughness of surface 12a is greater than the surface roughness of back surface 12b, the microscopic surface area of ​​surface 12a increases, and the bonding area between the first metal layer 12c and the first connector 13 and the second connector 14 can be increased. This increases the bonding strength between the connecting conductor 12 and the first connector 13 and the second connector 14, and also reduces the connection resistance. Furthermore, the connection resistance between the first source electrode 3e of the first MOSFET element 3 and the second source electrode 4e of the second MOSFET element 4 can be reduced, thereby improving connection reliability.

[0088] Furthermore, if the surface roughness of the back surface 12b is greater than that of the front surface 12a, the microscopic surface area of ​​the back surface 12b can be increased. The connecting conductor 12 is attached to the back surface 5b of the light-receiving driving element 5 via an adhesive (not shown) or an adhesive sheet 15 (see Figure 11) which will be described later. Therefore, by increasing the microscopic surface area of ​​the back surface 12b, the bonding area between the connecting conductor 12 and the light-receiving driving element 5 can be increased, thereby increasing the adhesive strength between them. This improves the alignment accuracy of the connecting conductor 12 with respect to the first MOSFET element 3 and the second MOSFET element 4 when mounting the light-receiving driving element 5 with the connecting conductor 12 attached to it onto the first MOSFET element 3 and the second MOSFET element 4.

[0089] Furthermore, it is preferable that the first metal bump 13A constituting the first connector 13, the second metal bump 14A constituting the second connector 14, and the first metal layer 12c are made of the same type of metal. By doing so, the joint structure between the connecting conductor 12 and the first connector 13 and the second connector 14 becomes a joint of the same type of metal, thereby reducing contact resistance and further reducing the connection resistance between the first source electrode 3e and the second source electrode 4e.

[0090] Furthermore, the thermal expansion coefficient of the first metal layer 12c can be brought closer to that of the first connector 13 and the second connector 14, making it less likely for distortion and stress to occur in the joint structure between the first metal layer 12c and the first connector 13 and the second connector 14 in the connecting conductor 12 due to temperature changes. This improves the reliability of the connection between the first source electrode 3e and the second source electrode 4e.

[0091] Furthermore, since the first metal layer 12c and the first and second connecting members 13 and 14 are made of the same type of metal, electrochemical corrosion due to contact between dissimilar metals does not occur at the metal joint, thereby improving corrosion resistance.

[0092] Furthermore, it is preferable that the first metal bump 13A constituting the first connector 13 and the second metal bump 14A constituting the second connector 14 are gold bumps. It is also preferable that the first metal layer 12c is gold. By doing so, the electrical resistance of the first connector 13, the second connector 14 and the connecting conductor 12, and consequently the connection resistance between the first source electrode 3e and the second source electrode 4e can be further reduced. Note that the gold may contain unavoidable impurities mixed in during the manufacturing process. In other words, the first metal bump 13A, the second metal bump 14A and the first metal layer 12c can each be materials whose main constituent metal is gold.

[0093] Preferably, the first connector 13 is composed of a plurality of first metal bumps 13A, and the second connector 14 is composed of a plurality of second metal bumps 14A. This suppresses the tilt of the connecting conductor 12 when attaching it to the first connector 13 and the second connector 14. It also prevents the connecting conductor 12 from contacting the first MOSFET element 3 and / or the second MOSFET element 4, thereby preventing short-circuit failures. Furthermore, since the contact area between the connecting conductor 12 and the first connector 13, and the contact area between the connecting conductor 12 and the second connector 14 can be increased, the connection resistance between the first source electrode 3e and the second source electrode 4e can be reduced.

[0094] The material of the second metal layer 12d may be different from the material of the first metal layer 12c. For example, by making the second metal layer 12d a material with higher bending rigidity than the first metal layer 12c, it is possible to ensure the strength of the connecting conductor 12 while strengthening the metallic joint between the first metal layer 12c and the first connecting body 13 and the second connecting body 14.

[0095] When the first metal layer 12c is gold, the second metal layer 12d is preferably nickel or copper. This ensures the strength of the connecting conductor 12. Also, when the second metal layer 12d is copper, the resistance of the connecting conductor 12 can be reduced. Note that the copper or nickel may contain unavoidable impurities that are mixed in during the manufacturing process. In other words, the second metal layer 12d can be any metal layer whose main constituent metal is nickel or copper.

[0096] The connecting conductor 12 has a first connecting conductor portion 121, a second connecting conductor portion 122, and a third connecting conductor portion 123. When viewed along the first direction described above, the first connecting conductor portion 121 overlaps the first MOSFET element 3, and the second connecting conductor portion 122 overlaps the second MOSFET element 4. The third connecting conductor portion 123 is located between the first connecting conductor portion 121 and the second connecting conductor portion 122, and electrically connects the first connecting conductor portion 121 to the second connecting conductor portion 122. Also, when viewed along the first direction, the third connecting conductor portion 123 does not overlap the first MOSFET element 3 and the second MOSFET element 4. In the example shown in Figure 9A, the first to third connecting conductor portions 121 to 123 each have the same thickness along the X direction. However, the invention is not limited to this, and the first to third connecting conductor portions 121 to 123 may each have different thicknesses, or two or more portions may have the same thickness.

[0097] The drive circuit DRC is provided on the light-receiving drive element 5, and the light-receiving drive element 5 is mounted on the back surface 12b of the connecting conductor 12. This allows for miniaturization of the semiconductor relay 1.

[0098] Furthermore, the light-receiving driving element 5 is positioned to cover the surfaces of the first MOSFET element 3 and the second MOSFET element 4, respectively. By doing so, the first MOSFET element 3 and the second MOSFET element 4 and the light-receiving driving element 5 can be placed in close proximity, thereby further miniaturizing the semiconductor relay 1.

[0099] Furthermore, in the semiconductor relay 1, the light-emitting element 2 and the light-receiving element 51 are arranged facing each other with a predetermined distance between them in the X direction. This arrangement suppresses the increase in size of the semiconductor relay 1 in the Z direction, enabling a lower profile and miniaturization of the semiconductor relay 1.

[0100] Furthermore, in the drive circuit DRC, the photodetector, which receives the optical signal as the first drive signal from the light-emitting element 2, generates a current corresponding to the magnitude of the first drive signal, that is, the magnitude of the light intensity of the optical signal. Based on this current, the control circuit 52 outputs a second drive signal to the output circuit OPC.

[0101] In this way, the input circuit IPC and the output circuit OPC can be electrically isolated while the output signal can be switched on and off by optical coupling.

[0102] <Modification 1> Figure 11 is a diagram corresponding to Figure 2 of the semiconductor relay according to Modification 1. In Figure 11 and the subsequent drawings, the same reference numerals are used for parts that are the same as in Embodiment 1, and detailed explanations are omitted.

[0103] The semiconductor relay 1 shown in Figure 11 differs from the semiconductor relay 1 shown in Embodiment 1 in that it further includes an adhesive sheet 15 interposed between the light-receiving driving element 5 and the connecting conductor 12.

[0104] By providing the adhesive sheet 15 in the aforementioned position, the back surface 12b of the connecting conductor 12 can be securely bonded to the back surface 5b of the light-receiving driving element 5. This fixes the position of the connecting conductor 12 and ensures that the connecting conductor 12 is securely attached to the first connector 13 and the second connector 14.

[0105] <Modification 2> Figure 12 is a diagram corresponding to Figure 2 of the semiconductor relay according to Modification 2.

[0106] The semiconductor relay 1 shown in Figure 12 differs from the semiconductor relay 1 shown in Embodiment 1 in the following respects. First, the second input terminal 7 and the second output terminal 9 are flat plates whose surface normals are aligned in the Z direction. Although not shown, the first input terminal 6 and the first output terminal 8 are also flat plates whose surface normals are aligned in the Z direction. The back surfaces of the first input terminal 6, the second input terminal 7, the first output terminal 8, and the second output terminal 9 are all exposed to the outside from the back surface of the housing 10. In other words, the back surfaces of the first input terminal 6, the second input terminal 7, the first output terminal 8, and the second output terminal 9 correspond to the first input side external terminal portion 61, the second input side external terminal portion 71, the first output side external terminal portion 81, and the second output side external terminal portion 91 shown in Embodiment 1.

[0107] Furthermore, the first MOSFET element 3, the second MOSFET element 4, the connecting conductor 12, the light-receiving driving element 5, and the light-emitting element 2 are stacked in this order along the Z direction. Therefore, the first direction in this modified example is the Z direction. As in Embodiment 1, a first connector 13 is interposed between the first MOSFET element 3 and the connecting conductor 12, and a second connector 14 is interposed between the second MOSFET element 4 and the connecting conductor 12. On the other hand, in this modified example, the light-emitting element 2 is placed on the surface of the light-receiving element 51 of the light-receiving driving element 5 via a light-transmitting resin 10b.

[0108] According to this embodiment, the semiconductor relay 1 can be miniaturized in the Z direction. Furthermore, this embodiment can achieve the same effects as the configuration shown in Embodiment 1. Specifically, the connection resistance between the first source electrode 3e of the first MOSFET element 3 and the second source electrode 4e of the second MOSFET element 4 can be reduced, thereby improving connection reliability. In addition, the parasitic inductance component on the output side of the semiconductor relay 1 can be reduced, thereby reducing insertion loss.

[0109] In addition, a transparent plate such as a glass plate may be interposed between the surface of the light-receiving element 51 and the light-emitting element 2, rather than the light-transmitting resin 10b. In other words, the light-emitting element 2 may be placed on the surface of the light-receiving element 51 via a light-transmitting material.

[0110] (Embodiment 2) Figure 13 is an equivalent circuit diagram of a semiconductor relay according to Embodiment 2. Figure 14 is a perspective view of the semiconductor relay. Figure 15 is a view of the semiconductor relay from above. Figure 16 is a view of the semiconductor relay from direction C shown in Figure 14.

[0111] The semiconductor relay described in this specification is not limited to the optically coupled semiconductor relay shown in Embodiment 1. In this embodiment, a semiconductor relay 20 that switches an output signal on and off by capacitive coupling while the input circuit IPC and the output circuit OPC are electrically isolated will be described.

[0112] As shown in Figure 13, the semiconductor relay 20 of this embodiment differs from the semiconductor relay 1 of Embodiment 1 in that an oscillation circuit 31 is provided instead of a light-emitting element 2 as the input circuit IPC. It also differs from the semiconductor relay 1 of Embodiment 1 in that it has a boost circuit 32 and a control circuit 33 as the drive circuit DRC.

[0113] The boost circuit 32 is a known charge pump type boost circuit having capacitors C1 and C2 and diodes Di1 to Di3. Capacitors C1 and C2, which are connected in series between the oscillator circuit 31 and the boost circuit 32, isolate the input circuit IPC and the output circuit OPC of the semiconductor relay 20. The number of diodes and their connection relationships arranged after the boost circuit 32 are not particularly limited to the example shown in Figure 13.

[0114] In this embodiment, the driving element 30 is an IC in which the oscillation circuit 31, the boost circuit 32, and the control circuit 33 are integrated on a single semiconductor chip. However, it is not limited to this, and for example, the oscillation circuit 31, the boost circuit 32, and the control circuit 33 may each be separate components, and the three components may be connected by wires 11 or electrically connected on a printed circuit board. Alternatively, the boost circuit 32 and the control circuit 33 may be integrated on a single semiconductor chip, and the oscillation circuit 31 and this semiconductor chip may be connected by wires 11 or electrically connected on a printed circuit board.

[0115] The operation of the semiconductor relay 20 will be described below.

[0116] When an input signal is input between the first input terminal 6 and the second input terminal 7, the oscillation circuit 31 generates a first oscillation signal S1 and a second oscillation signal S2, which are pulse signals having a predetermined oscillation frequency and inverted phases relative to each other. The first oscillation signal S1 and the second oscillation signal S2 correspond to the first drive signal in Embodiment 1.

[0117] In the boost circuit 32, a signal is generated by adding the second oscillation signal S2, which has passed through capacitor C2 and diode Di2, to the first oscillation signal S1, which has passed through capacitor C1 and diode Di1. This signal is input to the control circuit 33.

[0118] The control circuit 33 is a charge / discharge circuit, and it inputs a second drive signal corresponding to the signal generated by the boost circuit 32 to the gate electrodes G of the first MOSFET element 3 and the second MOSFET element 4, respectively.

[0119] When the voltage of the second drive signal output from the control circuit 33 becomes higher than the threshold voltages of the first MOSFET element 3 and the second MOSFET element 4, the first MOSFET element 3 and the second MOSFET element 4 turn on, respectively. As a result, the first output terminal 8 and the second output terminal 9 become conductive. This allows a signal to be transmitted between the first output terminal 8 and the second output terminal 9.

[0120] On the other hand, when no input signal is input between the first input terminal 6 and the second input terminal 7, the oscillation circuit 31 does not operate, and the second drive signal is not input from the boost circuit 32 to the control circuit 33. As a result, the control circuit 33 extracts and discharges the charge stored in the gate electrodes G of the first MOSFET element 3 and the second MOSFET element 4. Consequently, the first MOSFET element 3 and the second MOSFET element 4 are turned off, and the connection between the first output terminal 8 and the second output terminal 9 becomes non-conductive. This interrupts signal transmission between the first output terminal 8 and the second output terminal 9.

[0121] Furthermore, as shown in Figures 14 to 16, in the semiconductor relay 20, the drive element 30, the first MOSFET element 3, and the second MOSFET element 4 are arranged with a gap in the X direction so that their sides face each other.

[0122] The surface 30a of the driving element 30 has a first electrode 30c, a second electrode 30d, two third electrodes 30e, and a fourth electrode 30f formed on the surface 30a of the driving element 30. The first electrode 30c is electrically connected to the surface 6a of the first input terminal 6 via a wire 11. The second electrode 30d is electrically connected to the surface 7a of the second input terminal 7 via a wire 11. One of the two third electrodes 30e is electrically connected to the first gate electrode 3d of the first MOSFET element 3 via a wire 11, and the other is electrically connected to the second gate electrode 4d of the second MOSFET element 4 via a wire 11. The fourth electrode 30f is electrically connected to the second source electrode 4e of the second MOSFET element 4 via a wire 11.

[0123] Furthermore, an insulating adhesive sheet 30g is formed on the back surface 30b of the drive element 30, and the adhesive sheet 30g is exposed to the outside from the back surface of the housing 10.

[0124] Furthermore, a first MOSFET element 3 is positioned on the surface 8a of the first output terminal 8, and a second MOSFET element 4 is positioned on the surface 9a of the second output terminal 9. Although not shown in the figures, a first connector 13 consisting of six first metal bumps 13A is provided on the first source electrode 3e of the first MOSFET element 3, and a second connector 14 consisting of six second metal bumps 14A is provided on the second source electrode 4e of the second MOSFET element 4. The arrangement of the first metal bumps 13A relative to the first source electrode 3e and the arrangement of the second metal bumps 14A relative to the second source electrode 4e are the same as those shown in Figure 8.

[0125] The connecting conductor 12 is positioned above the first MOSFET element 3 and the second MOSFET element 4, and is connected to the first metal bump 13A and the second metal bump 14A, respectively. However, the connecting conductor 12 and the driving element 30 are spaced apart in the X direction.

[0126] According to this embodiment, the same effects as those achieved by the configuration shown in Embodiment 1 can be achieved. Specifically, the connection resistance between the first source electrode 3e of the first MOSFET element 3 and the second source electrode 4e of the second MOSFET element 4 can be reduced, thereby improving connection reliability. Furthermore, the parasitic inductance component on the output side of the semiconductor relay 20 can be reduced, thereby reducing insertion loss.

[0127] Furthermore, according to this embodiment, the output signal can be switched on and off by capacitive coupling while the input circuit IPC and the output circuit OPC are electrically isolated from each other.

[0128] Alternatively, the semiconductor relay 20 may be a magnetically coupled type. In this case, a pair of inductors (not shown) are used instead of capacitors C1 and C2. One inductor is connected in parallel to the oscillation circuit 31. The other inductor is connected in parallel to the boost circuit 32. The oscillation circuit 31 outputs a first drive signal that varies periodically over time. The first drive signal is transmitted to the boost circuit 32 via the magnetic coupling between the pair of inductors.

[0129] In this case, the output signal can be switched on and off by the magnetic coupling of a pair of inductors while the input circuit IPC and the output circuit OPC are electrically isolated from each other.

[0130] The semiconductor relay of this disclosure is useful because it can reduce connection resistance and has high connection reliability in the connection between the connecting conductor and the connector that connects the source electrodes of the output element.

[0131] 1. Semiconductor relay 2. Light-emitting element 3. First MOSFET element 3a Front surface 3a1 First mounting area 3a2 First non-mounting area 3b Back surface 3d First gate electrode 3e First source electrode 3e1 First electrode body 3e2 First enlarged electrode 3f First drain electrode 4. Second MOSFET element 4a Front surface 4a1 Second mounting area 4a2 Second non-mounting area 4b Back surface 4d Second gate electrode 4e Second source electrode 4e1 Second electrode body 4e2 Second enlarged electrode 4f Second drain electrode 5. Light-receiving driving element 5a Front surface 5b Back surface 51 Light-receiving element 52 Control circuit 6. First input terminal 61 First input side external terminal 62 Wire connection part 63 Branch part 7. Second input terminal 71 Second input side external terminal 72 73 Light-emitting element mounting section Branch section 73a-73c Branch section 8 First output terminal 81 First output side external terminal section 82 First MOSFET mounting section 83 Branch section 9 Second output terminal 91 Second output side external terminal section 92 Second MOSFET mounting section 93 Branch section 10 Housing 10a Light-shielding resin 10b Light-transmitting resin 11 Wire 12 Connecting conductor 121 First connecting conductor section 122 Second connecting conductor section 123 Third connecting conductor section 12a Surface (surface of connecting conductor, or surface of the first metal layer) 12b Back (back of connecting conductor, or back of the second metal layer) 12b1 Back (back of the periphery) 12c First metal layer 12c1 Back (back of the first metal layer) 12d Second metal layer 12d1 Surface (surface of the second metal layer) 12d2 Peripheral part 13 First connector 13A First metal bump 14 Second connector 14A Second metal bump 15 Adhesive sheet 30 Driving element 31 Oscillator circuit 30a Front surface 30b Back surface 30c-30f First to fourth electrodes 30g Adhesive sheet 32 ​​Boost circuit 33 Control circuit

Claims

1. The device comprises an input circuit, a drive circuit, an output circuit, and a connecting conductor having a laminated structure of a first metal layer and a second metal layer, and being plate-shaped, wherein the input circuit and the output circuit are electrically insulated from each other, the input circuit has a first input terminal, a second input terminal and an input element, and outputs a first drive signal to the drive circuit based on an input signal input between the first input terminal and the second input terminal, the drive circuit outputs a second drive signal to the output circuit based on the first drive signal, the output circuit has a first output terminal, a second output terminal and an output element, and makes the connection between the first output terminal and the second output terminal conductive or non-conductive based on the second drive signal, the output element has a first MOSFET element and a second MOSFET element electrically connected to the drive circuit, the first MOSFET element has a first gate electrode and a first source electrode formed on its surface, and a first connector is provided on the surface of the first source electrode, The second MOSFET element has a second gate electrode and a second source electrode formed on its surface, a second connector provided on the surface of the second source electrode, each of the first and second connectors being a metal bump, the surface of the connecting conductor being formed of the first metal layer, the back surface of the connecting conductor being the opposite surface being formed of the second metal layer, each of the first and second connectors being joined to the surface of the first metal layer being the surface of the connecting conductor, the flatness of the surface of the first metal layer being higher than the flatness of the back surface of the second metal layer being the back surface of the connecting conductor, and the first and second source electrodes being electrically connected to each other via the first connector, the connecting conductor, and the second connector, respectively, in a semiconductor relay.

2. The semiconductor relay according to claim 1, wherein the area of ​​the back surface of the second metal layer is larger than the area of ​​the back surface of the first metal layer.

3. The semiconductor relay according to claim 1 or 2, wherein the surface roughness of the surface of the first metal layer is different from the surface roughness of the back surface of the second metal layer.

4. The semiconductor relay according to any one of claims 1 to 3, wherein each of the first connector, the second connector, and the first metal layer has gold as its main constituent metal.

5. The semiconductor relay according to any one of claims 1 to 4, wherein each of the first connector and the second connector is composed of a plurality of metal bumps, and each of the plurality of metal bumps is a metal bump.

6. The semiconductor relay according to any one of claims 1 to 5, wherein the material of the second metal layer is different from the material of the first metal layer.

7. The semiconductor relay according to any one of claims 1 to 6, wherein the second metal layer has nickel or copper as its main constituent metal.

8. The semiconductor relay according to any one of claims 1 to 7, wherein the drive circuit is provided on the drive element, and the drive element is mounted on the back surface of the connecting conductor.

9. The semiconductor relay according to claim 8, further comprising an adhesive sheet interposed between the driving element and the connecting conductor.

10. The semiconductor relay according to claim 8 or 9, wherein the input element is a light-emitting element, the driving element includes a light-receiving element and a control circuit, the light-receiving element, upon input of the first driving signal, generates a current corresponding to the magnitude of the first driving signal, and the control circuit outputs the second driving signal to the output circuit based on the current.

11. The semiconductor relay according to any one of claims 1 to 7, wherein the drive circuit is provided on a drive element, the drive element includes a capacitor, and the input circuit and the output circuit are electrically isolated by the capacitor.

12. The semiconductor relay according to any one of claims 1 to 7, wherein the drive circuit is provided on a drive element, the drive element includes a pair of inductors, and the input circuit and the output circuit are electrically isolated from each other by the pair of inductors.

13. The semiconductor relay according to claim 10, wherein the light-emitting element is arranged on the surface of the light-receiving element via a light-transmitting material.

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