Semiconductor device

Abstract

To reduce a failure risk of a semiconductor device by controlling the stress influence on a semiconductor element.SOLUTION: A semiconductor device according to an embodiment includes a first transistor, a light-receiving element provided on and in contact with the first transistor in a first direction with a light-receiving surface facing in the first direction, a light-emitting element provided with an illuminating surface facing the light-receiving surface of the light-receiving element in the first direction, and a first resin member that seals the first transistor, the light-receiving element, and the light-emitting element and has the light-transmitting property. An apex of a surface of the light-receiving element that is in contact with the first transistor is provided at a position not overlapping the first transistor in the first direction.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The embodiments relate to a semiconductor device. [Background technology]

[0002] 2. Description of the Related Art A photorelay device is a known semiconductor device. The photorelay device is a contactless relay that includes a light-emitting element and a light-receiving element and is used to transmit various signals. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 7273494 [Patent Document 2] Japanese Patent Application Laid-Open No. 2002-184936 [Patent Document 3] Patent No. 2682198 Summary of the Invention [Problem to be solved by the invention]

[0004] The effect of stress on semiconductor elements is controlled, reducing the risk of failure of semiconductor devices. [Means for solving the problem]

[0005] The semiconductor device according to the embodiment includes a first transistor, a light receiving element that is in contact with the first transistor in a first direction and has a light receiving surface facing the first direction, a light emitting element that is in contact with the light receiving surface of the light receiving element in the first direction and has an irradiation surface that faces the light receiving surface of the light receiving element in the first direction, and a first resin member that seals the first transistor, the light receiving element, and the light emitting element, respectively, and is translucent, and the vertex of the surface of the light receiving element that is in contact with the first transistor is positioned so as not to overlap with the first transistor in the first direction. [Brief explanation of the drawings]

[0006] [Figure 1] FIG. 1 is a perspective view showing an example of an external structure of a photorelay device according to a first embodiment. [Figure 2] FIG. 2 is a cross-sectional view showing an example of the internal structure of the photorelay device according to the first embodiment. [Figure 3] FIG. 3 is a plan view showing an example of a planar layout of various elements included in the photorelay device according to the first embodiment. [Figure 4] 4 is a cross-sectional view taken along line IV-IV in FIG. 3, showing an example of the internal structure of the photorelay device according to the first embodiment. [Figure 5] FIG. 5 is a circuit diagram showing an example of a circuit configuration of the photorelay device according to the first embodiment. [Figure 6] FIG. 6 is a diagram showing the influence of stress on the photorelay device according to the first embodiment. [Figure 7] FIG. 7 is a cross-sectional view showing an example of the internal structure of a photorelay device according to a second embodiment. [Figure 8] FIG. 8 is a diagram showing an example of a dicing step for the light-receiving element according to the second embodiment. [Figure 9] FIG. 9 is a cross-sectional view showing an example of the internal structure of a photorelay device according to a third embodiment. [Figure 10] FIG. 10 is a diagram showing an example of a dicing process for the light-receiving element according to the third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0007] Hereinafter, embodiments will be described with reference to the drawings. In the following description, components having substantially the same functions and configurations will be designated by the same reference numerals. When elements having similar configurations are to be particularly distinguished from one another, different letters or numbers may be added to the end of the same reference numerals.

[0008] In the following description, when a first element is "connected" to another first element, it includes the first element being indirectly connected to the second element via an intermediate element that is always or selectively conductive, or directly connected to the second element without an intermediate element.

[0009] 1. First embodiment 1.1 Overall structure A first embodiment will be described below: In this embodiment, a photorelay device will be described as an example of a semiconductor device.

[0010] Fig. 1 is a perspective view showing an example of the external structure of the photorelay device according to the first embodiment. As shown in Fig. 1, the photorelay device 1 includes a housing structure sealed with a first resin member 80, from which lead frames 10a, 10b, 20a, and 20b extend.

[0011] The lead frames 10a, 10b, 20a, and 20b include, for example, gold-plated copper plates. The lead frames 10a and 10b and the lead frames 20a and 20b extend in directions opposite to each other, sandwiching the first resin member 80. In the following description, the direction in which the lead frames 20a and 20b extend from the first resin member 80 is referred to as the X direction. The direction in which the lead frames 20a and 20b are aligned is referred to as the Y direction.

[0012] Ends of the lead frames 10a and 10b function as input terminals 11a and 11b of the photorelay device 1. The input terminals 11a and 11b are connected to, for example, an external power source and receive various signals.

[0013] Ends of the lead frames 20a and 20b function as output terminals 21a and 21b of the photorelay device 1. The output terminals 21a and 21b are connected to, for example, an external device and transmit various signals.

[0014] The first resin member 80 includes, for example, an epoxy resin containing a shielding material such as carbon or silica. The first resin member 80 is provided to cover the photorelay device 1 except for parts of the lead frames 10a, 10b, 20a, and 20b. The first resin member 80 protects the components of the photorelay device 1 from physical disturbances. The first resin member 80 also has light-blocking properties. The first resin member 80 shields the photorelay device 1 from external light and blocks the irradiated light generated inside the photorelay device 1 from leaking out.

[0015] Fig. 2 is a cross-sectional view showing an example of the internal structure of the photorelay device 1 according to the first embodiment. As shown in Fig. 2, the photorelay device 1 further includes a transistor 30, a light receiving element 40, a light emitting element 50, a second resin member 90, a third resin member 100, and a plurality of wirings CW.

[0016] The lead frame 10 includes lead frames 10a and 10b. In the following description, the lead frames 10a and 10b may be referred to as the lead frame 10 without distinction.

[0017] The lead frame 20 includes lead frames 20a and 20b. In the following description, the lead frames 20a and 20b may be referred to as the lead frame 20 without distinction.

[0018] The portions of the lead frames 10 and 20 sealed with the first resin member 80 are arranged side by side in directions perpendicular to the X and Y directions. In the following description, the direction from the lead frame 10 toward the lead frame 20 is referred to as the Z direction or upward direction. The direction from the lead frame 20 toward the lead frame 10 is referred to as the -Z direction or downward direction.

[0019] The portion of the lead frame 10 sealed with the first resin member 80 extends in the X direction from the portion of the lead frame 10 extending outside the first resin member 80. The portion of the lead frame 20 sealed with the first resin member 80 extends in the opposite direction to the X direction from the portion of the lead frame 20 extending outside the first resin member 80.

[0020] The transistor 30 is, for example, an enhancement-type n-channel MOSFET (Metal Oxide Semiconductor Field Effect Transistor). The transistor 30 is provided on and in contact with the lower surface of the lead frame 20. The transistor 30 has, for example, a configuration in which a circuit is provided on the surface of the element.

[0021] The light receiving element 40 is, for example, a PDA (Photo Diode Array) or a phototransistor. The following describes a case where the light receiving element 40 is a PDA. The light receiving element 40 has a rectangular parallelepiped shape. The light receiving element 40 has, for example, a configuration in which a circuit is provided on the surface of the element. The light receiving element 40 is provided on the lower surface of the transistor 30. A light receiving surface is provided on the lower surface of the light receiving element 40. In other words, the light receiving surface of the light receiving element 40 faces the side (downward) where the lead frame 10 is arranged.

[0022] The light emitting element 50 is, for example, an LED (Light Emitting Diode). The light emitting element 50 is provided on the upper surface of the lead frame 10. An irradiation surface is provided on the upper surface of the light emitting element 50. That is, the irradiation surface of the light emitting element 50 faces the side (upward) where the lead frame 20 is arranged. The irradiation surface of the light emitting element 50 faces the light receiving surface of the light receiving element 40 in the Z direction.

[0023] The second resin member 90 is, for example, an epoxy resin. The second resin member 90 is provided inside the first resin member 80. The second resin member 90 has a portion interposed between the light receiving element 40 and the light emitting element 50. The second resin member 90 covers parts of the lead frames 10 and 20, the transistor 30, the light receiving element 40, the light emitting element 50, and the multiple wirings CW, fixing the position of each element and insulating between the elements. The second resin member 90 is translucent.

[0024] The third resin member 100 is made of, for example, silicone. The third resin member 100 is provided on the lead frame 10 inside the second resin member 90 so as to cover the light emitting element 50. The third resin member 100 fixes the position of the light emitting element 50 and protects the light emitting element 50 from physical or electrical disturbances. The third resin member 100 is translucent.

[0025] The multiple wirings CW are, for example, bonding wires, and electrically connect the components together.

[0026] 1.2 Planar layout FIG. 3 illustrates a planar layout of the photorelay device according to the first embodiment. FIG. 3 is a plan view illustrating an example of a planar layout of various elements included in the photorelay device according to the first embodiment. Portion (A) of FIG. 3 corresponds to the planar layout of the lead frames 20a and 20b, the transistor 30, and the light-receiving element 40 when the photorelay device 1 is viewed from above. Portion (B) of FIG. 3 corresponds to the planar layout of the lead frames 10a and 10b and the light-emitting element 50 when the photorelay device 1 is viewed from below. Note that the first resin member 80, the second resin member 90, and the third resin member 100 are omitted from FIG. 3 . As illustrated in FIG. 3 , the photorelay device 1 further includes adhesive layers 61a, 61b, 62a, 62b, and 63. The transistor 30 includes transistors 30a and 30b. The wiring CW includes wirings 70, 71, 72, 73, and 74.

[0027] As shown in part (A) of FIG. 3 , the lead frames 20a and 20b have first portions 20a-1 and 20b-1, whose ends extend outside the first resin member 80 and function as output terminals 21a and 21b, respectively, and second portions 20a-2 and 20b-2 extending in the X direction. The first portion 20a-1 of the lead frame 20a and the first portion 20b-1 of the lead frame 20b are arranged side by side in this order in the Y direction. The second portion 20a-2 of the lead frame 20a and the second portion 20b-2 of the lead frame 20b are arranged side by side in this order in the Y direction. One end of the second portion 20a-2 of the lead frame 20a contacts the first portion 20a-1 of the lead frame 20a. One end of the second portion 20b-2 of the lead frame 20b contacts the first portion 20b-1 of the lead frame 20b.

[0028] The transistors 30a and 30b have, for example, substantially the same configuration and shape, and are arranged side by side in overlapping positions when viewed in the Y direction.

[0029] The transistor 30a is provided on the lower surface of the second portion 20a-2 of the lead frame 20a via an adhesive layer 61a. The transistor 30a includes electrodes 31a, 32a, and 33a.

[0030] The electrode 31a is provided on the upper surface of the transistor 30a and is in contact with the adhesive layer 61a. The electrode 31a functions as the drain terminal of the transistor 30a.

[0031] The electrode 32a is provided on the bottom surface of the transistor 30a. In the example shown in FIG. 3, two electrodes 32a are provided side by side in the Y direction, but the two electrodes 32a are connected inside the transistor 30a. The arrangement of the electrodes 32a is not limited to the configuration and arrangement shown in FIG. 3. For example, the electrode 32a may be a single rectangular electrode extending in the Y direction. The electrode 32a functions as the source terminal of the transistor 30a.

[0032] The electrode 33a is provided on the bottom surface of the transistor 30a. When viewed from the electrode 32a, the electrode 33a is provided in a position opposite to the X direction. In the example shown in FIG. 3, the two electrodes 33a are provided side by side in the Y direction, but the two electrodes 33a are connected inside the transistor 30a. The arrangement of the electrodes 33a is not limited to the configuration and arrangement shown in FIG. 3. For example, the electrode 33a may be a single rectangular electrode extending in the Y direction. The electrode 33a functions as the gate terminal of the transistor 30a.

[0033] The transistor 30b is provided on the lower surface of the second portion 20b-2 of the lead frame 20b via an adhesive layer 61b. The transistor 30b includes electrodes 31b, 32b, and 33b.

[0034] The electrode 31b is provided on the upper surface of the transistor 30b and is in contact with the adhesive layer 61b, and functions as the drain terminal of the transistor 30b.

[0035] The electrode 32b is provided on the bottom surface of the transistor 30b. In the example shown in Fig. 3, the two electrodes 32b are provided side by side in the Y direction, but the two electrodes 32b are connected inside the transistor 30b. The arrangement of the electrodes 32b is not limited to the configuration and arrangement shown in Fig. 3. For example, the electrode 32b may be a single rectangular electrode extending in the Y direction. The electrode 32b functions as the source terminal of the transistor 30b.

[0036] The electrode 33b is provided on the bottom surface of the transistor 30b. When viewed from the electrode 32b, the electrode 33b is provided in a position opposite to the X direction. In the example shown in FIG. 3, the two electrodes 33b are provided side by side in the Y direction, but the two electrodes 33b are connected inside the transistor 30b. The arrangement of the electrodes 33b is not limited to the configuration and arrangement shown in FIG. 3. For example, the electrode 33b may be a single rectangular electrode extending in the Y direction. The electrode 33b functions as the gate terminal of the transistor 30b.

[0037] The light receiving element 40 is provided on the lower surfaces of the transistors 30a and 30b via adhesive layers 62a and 62b so as to straddle the transistors 30a and 30b in the long side direction (Y direction). The light receiving element 40 is provided at a position that does not overlap with the electrodes 32a and 33a of the transistor 30a and the electrodes 32b and 33b of the transistor 30b in the Z direction. In the example shown in Fig. 3, the light receiving element 40 is provided at a position in the X direction when viewed from the electrodes 32a, 32b, 33a, and 33b.

[0038] The short sides of the bonding surface of the light receiving element 40 to the transistors 30a and 30b are not located on the bottom surface of either the transistors 30a or 30b. In other words, the vertices of the bonding surface of the rectangular parallelepiped light receiving element 40 to the transistors 30a and 30b are located at positions that do not overlap with either the transistors 30a and 30b in the Z direction.

[0039] The light receiving element 40 includes electrodes 41 and 42. The electrodes 41 and 42 are provided on the lower surface of the light receiving element 40. The electrodes 41 and 42 are provided at positions that do not overlap with the light receiving surface of the light receiving element 40. In the example shown in FIG. 3, the electrodes 41 and 42 are provided side by side in the Y direction. The electrode 41 functions as an anode terminal of the light receiving element 40. The electrode 42 functions as a cathode terminal of the light receiving element 40.

[0040] As shown in part (B) of FIG. 3 , the lead frames 10a and 10b each have first portions 10a-1 and 10b-1, whose ends extend outside the first resin member 80 and function as input terminals 11a and 11b, respectively, second portions 10a-2 and 10b-2 extending in the Y direction, and third portions 10a-3 and 10b-3 extending in the X direction to connect the first and second portions. The first portion 10a-1 of the lead frame 10a and the first portion 10b-1 of the lead frame 10b are arranged side by side in the Y direction. The second portion 10a-2 of the lead frame 10a and the second portion 10b-2 of the lead frame 10b are arranged side by side in the X direction, and the second portion 10b-2 of the lead frame 10b is arranged closer to the first portions 10a-1 and 10b-1 of the lead frames 10a and 10b than the second portion 10a-2 of the lead frame 10a. The length of the short side of the second portion 10a-2 of the lead frame 10a is longer than the length of the short side of the second portion 10b-2 of the lead frame 10b and is sufficiently longer than the length of the short side of the light emitting element 50. The third portion 10a-3 of the lead frame 10a and the third portion 10b-3 of the lead frame 10b are arranged side by side in the Y direction so as to sandwich the second portions 10a-2 and 10b-2 of the lead frames 10a and 10b, respectively.

[0041] The light-emitting element 50 is provided on the upper surface of the second portion 10a-2 of the lead frame 10a via an adhesive layer 63. The light-emitting element 50 includes electrodes 51 and 52. The electrode 51 is provided on the lower surface of the light-emitting element 50 and is in contact with the adhesive layer 63. The electrode 52 is provided on the upper surface of the light-emitting element 50. The electrode 52 is provided in a position that does not overlap the light-emitting surface of the light-emitting element 50. The electrode 51 functions as an anode terminal of the light-emitting element 50. The electrode 52 functions as a cathode terminal of the light-emitting element 50.

[0042] The adhesive layer 61a is made of a conductive connecting material, such as silver paste. The adhesive layer 61a bonds and fixes the lower surface of the second portion 20a-2 of the lead frame 20a to the upper surface of the transistor 30a. The adhesive layer 61a electrically connects the electrode 31a of the transistor 30a to the lead frame 20a.

[0043] The adhesive layer 61b is made of a conductive connecting material, such as silver paste. The adhesive layer 61b bonds and fixes the lower surface of the second portion 20b-2 of the lead frame 20b to the upper surface of the transistor 30b. The adhesive layer 61b electrically connects the electrode 31b of the transistor 30b to the lead frame 20b.

[0044] The adhesive layer 62a is made of an insulating connecting member and bonds the bottom surface of the transistor 30a and the top surface of the light receiving element 40 together.

[0045] The adhesive layer 62b is made of an insulating connecting member and bonds the bottom surface of the transistor 30b and the top surface of the light receiving element 40 together.

[0046] The adhesive layer 63 is made of a conductive connecting member, such as a silver paste. The adhesive layer 63 bonds and fixes the upper surface of the second portion 10a-2 of the lead frame 10a to the lower surface of the light-emitting element 50. The adhesive layer 63 electrically connects the electrode 51 of the light-emitting element 50 to the lead frame 10a.

[0047] The wirings 70, 71, 72, 73, and 74 are, for example, bonding wires. The wirings 70, 71, 72, 73, and 74 contain, for example, copper or gold. The wiring 70 connects the electrode 32a of the transistor 30a to the electrode 32b of the transistor 30b. The wiring 71 connects the electrode 33a of the transistor 30a to the electrode 33b of the transistor 30b. The wiring 72 connects the electrode 33a of the transistor 30a to the electrode 41 of the light-receiving element 40. The wiring 73 connects the electrode 32b of the transistor 30b to the electrode 42 of the light-receiving element 40. The wiring 74 electrically connects the electrode 52 of the light-emitting element 50 to the lead frame 10b. The wiring 72 may connect the electrode 33b of the transistor 30b and the electrode 41 of the light-receiving element 40, and the wiring 73 may connect the electrode 32a of the transistor 30a and the electrode 42 of the light-receiving element 40.

[0048] The wirings 72 and 73 are arranged so as not to intersect with either the wirings 70 or 71 in plan view. This reduces the height of the wirings 72 and 73 in the Z direction, and reduces the distance in the Z direction between the light receiving element 40 and the light emitting element 50. This reduces the height of the photorelay device 1 in the Z direction, and allows the device to be made more compact. However, the wiring arrangement is merely an example of the configuration and effects of the first embodiment, and the wirings may intersect, and the effects of the first embodiment are not lost due to the wiring intersections.

[0049] 1.3 Cross-sectional structure The cross-sectional structure of the photorelay device according to the first embodiment is shown in Figures 2 and 4. Figure 4 is a cross-sectional view taken along line IV-IV in Figure 3, showing an example of the cross-sectional structure of the photorelay device according to the first embodiment. Note that adhesive layers 61a, 61b, 62a, 62b, and 63, as well as multiple wirings CW, are omitted in Figure 4.

[0050] The lead frames 20a and 20b are provided so that their respective -Z direction surfaces (surfaces facing upward in the drawing) are substantially flush with each other. The transistors 30a and 30b are also provided so that their respective -Z direction surfaces (surfaces facing upward in the drawing) are substantially flush with each other.

[0051] 4, the light-receiving element 40 has a portion sandwiched in the Z direction between the transistor 30a and the second resin member 90, a portion sandwiched in the Z direction between the transistor 30b and the second resin member 90, and a portion sandwiched on both sides by the second resin member 90 in the Z direction. Specifically, the -Z direction surface of the light-receiving element 40 (the surface facing upward in the drawing) is uniformly in contact with the second resin member 90. At this time, the light-receiving element 40 and the second resin member 90 are in close contact. Furthermore, the Z direction surface of the light-receiving element 40 (the surface facing downward in the drawing) is in contact with, in the Y direction, the second resin member 90, the transistor 30a via the adhesive layer 62a, the second resin member 90, the transistor 30b via the adhesive layer 62b, and the second resin member 90, in that order.

[0052] 2 and 4, the light-emitting element 50 is provided at a position overlapping with the light-receiving element 40 in the Z direction. With this configuration, when light emitted from the light-emitting element 50 is received by the light-receiving element 40, loss of light can be suppressed, and the reliability of the photorelay device 1 can be improved.

[0053] 1.4 Circuit configuration The circuit configuration of the photorelay device according to the first embodiment is shown using Fig. 5. Fig. 5 is a circuit diagram showing an example of the circuit configuration of the photorelay device according to the first embodiment.

[0054] The transistors 30a and 30b are used to control the signals to be transmitted. The drain terminals of the transistors 30a and 30b are connected to the lead frames 20a and 20b, respectively. The source terminals of the transistors 30a and 30b are commonly connected to the cathode of the light-receiving element 40. The gate terminals of the transistors 30a and 30b are commonly connected to the anode of the light-receiving element 40.

[0055] The light receiving element 40 is, for example, a PDA including a control circuit 45 and several to a dozen photodiodes 46 connected in series. Both ends of the series-connected photodiodes 46 are connected to the control circuit 45. The control circuit 45 controls the transistors 30a and 30b using the voltage applied from the photodiodes 46 as a power supply voltage.

[0056] The anode of the light emitting element 50 is connected to the lead frame 10a, and the cathode is connected to the lead frame 10b. A signal transmitted via the photorelay device 1 is input to the lead frames 10a and 10b.

[0057] When a sufficient potential difference occurs between the lead frames 10a and 10b, the light-emitting element 50 turns on (light-emitting state). At this time, the light-receiving element 40 receives light from the light-emitting element 50 and generates a voltage between the anode and cathode. This turns the transistors 30a and 30b on, and the lead frames 20a and 20b are connected to each other. On the other hand, when the potential difference between the lead frames 10a and 10b decreases and the light-emitting element 50 turns off (light-extinguishing state), the transistors 30a and 30b turn off, and the lead frames 20a and 20b are insulated from each other.

[0058] 1.5 Effects The photorelay device according to the first embodiment can reduce the effects of stress on semiconductor elements. This effect will be explained using FIG. 6. FIG. 6 is a diagram showing the effects of stress on the photorelay device according to the first embodiment. In FIG. 6, the arrows indicate the direction of stress that the light-receiving element 40 receives on the cross-sectional structure of the photorelay device shown in FIG. 4. Note that the size and length of the arrows are not related to the magnitude of the stress.

[0059] In the photorelay device 1 according to the first embodiment, as shown in FIG. 6 , the light-receiving element 40 is subjected to stress from the transistors 30a and 30b and the second resin member 90. For example, the stresses the light-receiving element 40 receives are all compressive stresses. This is to prevent a decrease in reliability due to gaps created when the second resin member 90 peels off from the light-receiving element 40 and the semiconductor elements, resulting in multiple reflections and loss of light emitted from the light-emitting element 50 in the gaps. At this time, the −Z-direction surface (the upper surface in the drawing) of the light-receiving element 40 is in substantially uniform contact with the second resin member 90, so the light-receiving element 40 receives a substantially uniform compressive stress from the second resin member 90. Meanwhile, the Z-direction surface (the lower surface in the drawing) of the light-receiving element 40 includes a portion in contact with the transistors 30a and 30b and a portion in contact with the second resin member 90. Since the light-receiving element 40 receives different amounts of stress from the different materials, the stress distribution is non-uniform. Here, when focusing on the stress between the light receiving element 40 and the transistors 30a and 30b, there may be a location where the stress is concentrated on a part of the adhesive surface between the two. If the stress is concentrated in a part, there is a possibility that the transistors 30a and 30b and the circuitry provided on the surface of the light receiving element 40 may be destroyed, or the operation of the semiconductor element and the photorelay device 1 in which it is used may be affected in an unusual way.

[0060] In the photorelay device according to the first embodiment, a light-receiving element 40 is provided on two transistors 30a and 30b so as to straddle both of them. Furthermore, the vertices of the bonding surfaces of the light-receiving element 40 to the two transistors 30a and 30b are positioned so as not to overlap either of the transistors 30a and 30b in the Z direction. This structure allows stress between the light-receiving element 40 and the transistors 30a and 30b to be concentrated at stress concentration points SC shown in FIG. 6, for example. The stress concentration points SC occur, for example, on the line segments where the sides of the bonding surfaces of the transistors 30a and 30b to the light-receiving element 40 intersect with the bonding surfaces of the light-receiving element 40 to the transistors 30a and 30b.

[0061] At the stress concentration point SC shown in FIG. 6, the photoreceptor 40 is located on its bottom surface. Generally, a substrate is present on the bottom surface of a photoreceptor, making it less susceptible to stress. In addition, circuits are rarely provided on the bottom surface of a photoreceptor. Furthermore, when providing circuits on the surface of a semiconductor element, due to manufacturing constraints, the circuits are generally provided so as to avoid the edge portions of the surface. Therefore, in the transistors 30a and 30b, no circuits are provided on the surface at the stress concentration point SC. As a result, the photorelay device 1 is less susceptible to circuit breakdown due to stress concentration.

[0062] As described above, the photorelay device 1 according to the first embodiment can control the influence of stress between semiconductor elements by changing the structure without changing the material of the resin member. As a result, the risk of failure of the photorelay device 1 due to stress applied to the semiconductor elements can be reduced. Note that, because the occurrence of stress is also due to physical constants specific to the resin, the risk of failure due to temperature changes can also be reduced by taking into account and reflecting uneven stress caused by shrinkage at low temperatures and expansion at high temperatures. In other words, the effects of the first embodiment can be obtained even with respect to stress caused by temperature changes. 2. Second embodiment Next, a second embodiment will be described, focusing mainly on the configuration that differs from the first embodiment.

[0063] 2.1 Cross-sectional structure Fig. 7 is a cross-sectional view showing an example of the internal structure of the photorelay device according to the second embodiment. The cross section shown in Fig. 7 corresponds to the cross section shown in Fig. 4 in the first embodiment.

[0064] The photorelay device 1A according to the second embodiment includes a light-receiving element 40A instead of the light-receiving element 40. As shown in FIG. 7 , the YZ cross section of the light-receiving element 40A has an isosceles trapezoidal shape, with the longer of the two bases being the bonding surface side to the transistors 30a and 30b. That is, the Y-direction side of the light-receiving element 40A is inclined with respect to the Z direction. Although not shown, the XZ cross section of the light-receiving element 40A also has an isosceles trapezoidal shape, with the longer of the two bases being the bonding surface side to the transistors 30a and 30b. That is, the X-direction side of the light-receiving element 40A is inclined with respect to the Z direction. In summary, the light-receiving element 40A has a quadrangular truncated pyramid shape, with the bonding surface side to the transistors 30a and 30b being the larger of the two bases.

[0065] The short sides of the bonding surface of the light-receiving element 40A to the transistors 30a and 30b are not located on the bottom surfaces of either the transistors 30a or 30b. In other words, the vertices of the Z-direction surface (the surface facing downward in the drawing) of the light-receiving element 40A, which is the bonding surface to the transistors 30a and 30b, are located at positions that do not overlap with either the transistors 30a or 30b in the Z direction. Note that the vertices of the -Z-direction surface (the surface facing upward in the drawing) of the light-receiving element 40A may be located at positions that overlap with the transistors 30a or 30b in the Z direction.

[0066] 2.2 Manufacturing method A method for manufacturing the light receiving element 40A according to the second embodiment will be described with reference to Fig. 8. Fig. 8 is a diagram showing an example of a dicing step for the light receiving element according to the second embodiment.

[0067] The light receiving element 40A is manufactured by dicing a wafer on which a plurality of light receiving elements 40A are arranged in the X and Y directions, into individual pieces. In the dicing process for manufacturing the light receiving element 40A according to the second embodiment, a dicing saw with a tapered blade as shown in FIG. 8 is used. By using a dicing saw with a tapered blade, the cross section is inclined to follow the taper of the blade. In this manner, a light receiving element 40A having a truncated quadrangular pyramid shape is manufactured.

[0068] 2.3 Effects The photorelay device 1A according to the second embodiment can reduce the effects of stress on the semiconductor element, as in the first embodiment. Furthermore, by forming the light-receiving element 40A in a truncated quadrangular pyramid shape, the stress distribution on the light-receiving element 40A changes, making it easier to disperse the stress, reducing the risk of stress concentration that could lead to breakdown of the circuitry provided on the surface or other failures of the photorelay device 1A.

[0069] 2.4 Variations The photorelay device 1A according to the second embodiment can be modified in various ways.

[0070] For example, the light-receiving element 40A may have an isosceles trapezoidal columnar shape, in which one of the YZ cross section and the XZ cross section has an isosceles trapezoidal shape and the other cross section has a rectangular shape. In this case, the light-receiving element 40A is manufactured in a dicing process by using a dicing saw with a tapered blade when dividing the light-receiving element 40A in the direction to form the isosceles trapezoidal shape, and by using a dicing saw with a rectangular blade when dividing the light-receiving element 40A in the direction to form the rectangular shape.

[0071] Furthermore, if the stress direction varies depending on the structure and arrangement of the photorelay device 1A, the light-receiving element 40A may have an inverted truncated pyramid shape with a narrow base area on the side bonded to the transistors 30a and 30b. This shape is effective in dispersing the stress applied to the light-receiving element 40A, for example, if another semiconductor element is provided on the -Z surface of the light-receiving element 40A and the direction of the stress that the light-receiving element 40A receives from the second resin member 90 becomes reverse. The light-receiving element 40A having the inverted truncated pyramid shape is manufactured by dicing a plurality of light-receiving elements 40A formed on a wafer from the backside using a tapered dicing saw.

[0072] 3. Third embodiment Next, a third embodiment will be described, focusing mainly on the configuration that differs from the first embodiment.

[0073] 3.1 Cross-sectional structure Fig. 9 is a cross-sectional view showing an example of the internal structure of the photorelay device according to the third embodiment. The cross section shown in Fig. 9 corresponds to the cross section shown in Fig. 4 in the first embodiment.

[0074] A photorelay device 1B according to the third embodiment includes a light receiving element 40B instead of the light receiving element 40. As shown in FIG. 9, the light receiving element 40B has a step in the Z direction on its Y-direction side, resulting in a convex shape in the YZ cross section. Although not shown, the light receiving element 40B also has a step in the Z direction on its X-direction side, resulting in a convex shape in the XZ cross section. That is, the light receiving element 40B has a stepped pyramid shape. In the example shown in FIG. 9, the light receiving element 40B has two steps on its Y-direction side in the YZ cross section, but this is not limiting. For example, the light receiving element 40B may have three or more steps on its Y-direction side in the YZ cross section. The same applies to the X-direction side in the XZ cross section.

[0075] The short sides of the bonding surface of the light-receiving element 40B to the transistors 30a and 30b are not located on the bottom surfaces of either the transistors 30a or 30b. In other words, the vertices of the Z-direction surface (the surface below the paper surface) of the light-receiving element 40B, which is the bonding surface to the transistors 30a and 30b, are located at positions that do not overlap with either the transistors 30a or 30b in the Z direction. Note that the -Z-direction surface (the surface above the paper surface) and the vertices of the step surface of the light-receiving element 40B may be located at positions that overlap with the transistor 30a or 30b in the Z direction.

[0076] 3.2 Manufacturing method A method for manufacturing a light-receiving element 40B according to the third embodiment will be described with reference to Fig. 10. Fig. 10 is a diagram showing an example of a dicing process for the light-receiving element according to the second embodiment. Below, a case will be described in which the light-receiving element 40B has a stepped pyramid shape with two steps on both the X-direction side and the Y-direction side.

[0077] The light-receiving element 40B is manufactured by dicing a wafer in which multiple light-receiving elements 40B are arranged in the X and Y directions. The dicing process for manufacturing the light-receiving element 40B according to the third embodiment is performed in two stages. In the first stage, as shown in part (A) of FIG. 10, a dicing saw with a relatively wide width is used to perform half-dicing, which is dicing performed halfway through the thickness of the wafer. Then, in the second stage, as shown in part (B) of FIG. 10, a dicing saw with a narrower width than that used in the first stage is used to perform dicing all the way through the center of the half-diced portion performed in the first stage, so as to completely separate the wafer. These steps result in a step on the side of the cross section. The width of the step can be adjusted by changing the width of the dicing saw blade used in each of the first and second stages. This allows the manufacture of a stepped pyramid-shaped light-receiving element 40B.

[0078] If the light receiving element 40B has a stepped pyramid shape with three or more steps, dicing is performed in stages equal to the number of steps.

[0079] 3.3 Effects The photorelay device 1B according to the third embodiment can reduce the effects of stress on the semiconductor elements, as in the first embodiment. Furthermore, by forming the light-receiving element 40B in a stepped pyramid shape, the stress distribution on the light-receiving element 40B changes, making it easier to disperse the stress, thereby reducing the risk of stress concentration that could lead to breakdown of the circuitry provided on the surface or other failures of the photorelay device 1B.

[0080] 3.4 Variations The photorelay device 1B according to the third embodiment can be modified in various ways.

[0081] For example, the light receiving element 40B may have a shape in which one of the XZ cross section and the YZ cross section has a step on the side and the other cross section has a rectangular shape without a step. In this case, the light receiving element 40B is manufactured by performing the above-mentioned multiple-stage dicing in the dicing process when dividing in the direction including the step, and by performing dicing all at once when dividing in the direction to form a rectangular shape.

[0082] Furthermore, if the stress direction varies depending on the structure and arrangement of the photorelay device 1B, the light-receiving element 40B may have an inverted step-pyramid shape with steps that rise toward the bonding surface with the transistors 30a and 30b. This shape is effective in dispersing the stress applied to the light-receiving element 40B, for example, when another semiconductor element is provided on the -Z surface of the light-receiving element 40B and the direction of the stress that the light-receiving element 40B receives from the second resin member 90 is reversed. The inverted step-pyramid-shaped light-receiving element 40B is manufactured by performing two-stage dicing from the back surface side on multiple light-receiving elements 40B formed on a wafer.

[0083] 4. Other Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as defined in the claims. [Explanation of symbols]

[0084] 1, 1A, 1B...Photorelay device 10 (10a, 10b), 20 (20a, 20b)...Lead frame 11a, 11b...input terminals 21a, 21b...Output terminals 30 (30a, 30b)...Transistor 31a, 31b, 32a, 32b, 33a, 33b, 41, 42, 51, 52...electrode 40, 40A, 40B...Light receiving element 45...Control circuit 46...Photodiode 50...Light emitting element 61a, 61b, 62a, 62b, 63...adhesive layer 70, 71, 72, 73, 74...Wiring 80...First resin member 90...Second resin member 100...Third resin member

Claims

1. a first transistor; a light-receiving element provided on the first transistor in a first direction, with a light-receiving surface facing the first direction; a light-emitting element provided such that an irradiation surface faces the light-receiving surface of the light-receiving element in the first direction; a first resin member that seals the first transistor, the light receiving element, and the light emitting element, and that has light-transmitting properties; Equipped with a vertex of a surface of the light receiving element that is in contact with the first transistor is provided at a position that does not overlap with the first transistor in the first direction; Semiconductor device.

2. a second transistor provided alongside the first transistor in a second direction perpendicular to the first direction; the light receiving element is further provided on the second transistor in the first direction and in contact with the second transistor, and straddles the first transistor and the second transistor in the second direction; a vertex of a surface of the light receiving element that is in contact with the second transistor is further disposed at a position that does not overlap with the second transistor in the first direction; the first resin member further encapsulates the second transistor; The semiconductor device according to claim 1.

3. The light receiving element is an area of ​​a surface in contact with the first transistor and an area of ​​a surface on which the light receiving surface is provided are different from each other; 3. The semiconductor device according to claim 1.

4. The side of the light receiving element is a slope inclined with respect to the first direction; 4. The semiconductor device according to claim 3.

5. The side of the light receiving element is having a step in the first direction; 4. The semiconductor device according to claim 3.

6. further comprising a first lead frame, a second lead frame, and a third lead frame; the light emitting element is provided on the first lead frame so as to be in contact with the first direction; the first transistor is provided on the second lead frame so as to be in contact with the second lead frame in the first direction; the second transistor is provided on the third lead frame so as to be in contact with the third lead frame in the first direction; 3. The semiconductor device according to claim 2.

7. a second resin member that seals the light-emitting element on the first lead frame and has light-transmitting properties, wherein the first resin member seals the light-emitting element via the second resin member; a third resin member that seals the first resin member, the first lead frame, the second lead frame, and the third lead frame and has a light-blocking property; Further provided with the first lead frame, the second lead frame, and the third lead frame each include a portion extending from the third resin member; 7. The semiconductor device according to claim 6.

Images