Semiconductor device

Abstract

To provide a more appropriate semiconductor device.SOLUTION: A semiconductor device comprises: a semiconductor element including an element first face and an element second face, which are directed to mutually opposite sides in a thickness direction, as well as an electrode provided on the side of the element first face; a conduction member including a principal surface opposed to the element first face and a rear surface directed to an opposite side of the principal surface; a conductive junction material which is interposed between the electrode and the principal surface of the conduction member; a resin part covering at least a portion of the conduction member, the semiconductor element and the conductive junction material; a first barrier layer which is interposed between the electrode and the conductive junction member and suppresses a compounding reaction of the electrode and the conductive junction material; and a surface protective film which is interposed between the element first face and the resin part and covers a part of the electrode.SELECTED DRAWING: Figure 13

Description

[Technical Field]

[0001] The present disclosure relates to semiconductor devices. [Background technology]

[0002] 2. Description of the Related Art Conventionally, as an example of a semiconductor device, a configuration has been proposed in which a semiconductor element is mounted on leads in a flip-chip mounting form.

[0003] For example, the semiconductor device disclosed in Patent Document 1 includes a semiconductor element having a plurality of electrodes, a plurality of leads, and a resin part covering the semiconductor element. The plurality of electrodes are joined to the plurality of leads by solder, and the semiconductor element is mounted on the plurality of leads in a flip-chip configuration. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Special Publication No. 2007-518282 Summary of the Invention [Problem to be solved by the invention]

[0005] Depending on the environment and operating conditions of a semiconductor device, the temperature of the semiconductor device may repeatedly rise and fall. In this case, thermal stress occurs due to the difference in thermal expansion between the semiconductor element and the lead. If this thermal stress causes cracks in the joint between the solder and the electrode, proper operation of the semiconductor device may be hindered.

[0006] In view of the above circumstances, an object of the present disclosure is to provide a semiconductor device that can prevent cracks from occurring at the bonding interface between the solder and the electrode. [Means for solving the problem]

[0007] The semiconductor device provided by the present disclosure includes a semiconductor element, a conductive member, a conductive bonding material, a resin portion, and a first barrier layer. The semiconductor element has a first element surface and a second element surface facing opposite each other in a thickness direction, and an electrode provided on the first element surface side. The conductive member has a main surface facing the first element surface and a back surface facing the opposite side to the main surface. The conductive bonding material is interposed between the electrode and the main surface of the conductive member. The resin portion covers at least a portion of the conductive member, the semiconductor element, and the conductive bonding material. The first barrier layer is interposed between the electrode and the conductive bonding material and suppresses a chemical reaction between the electrode and the conductive bonding material.

[0008] Preferably, the electrode comprises Cu.

[0009] Preferably, the conductive member contains Cu.

[0010] Preferably, the first barrier layer contains Ni.

[0011] Preferably, the conductive bonding material contains Sn.

[0012] Preferably, the electrode and the first barrier layer are in contact with each other.

[0013] Preferably, the conductive bonding material and the first barrier layer are in contact with each other.

[0014] Preferably, the semiconductor device further includes a second barrier layer interposed between the conductive member and the conductive bonding material and suppressing a chemical reaction between the conductive member and the conductive bonding material.

[0015] Preferably, the second barrier layer contains Ni.

[0016] Preferably, the second barrier layer includes a base layer and an auxiliary layer interposed between the conductive bonding material and the base layer.

[0017] Preferably, the conductive member and the second barrier layer are in contact with each other.

[0018] Preferably, the conductive bonding material and the second barrier layer are in contact with each other.

[0019] Preferably, the second barrier layer is larger than the first barrier layer when viewed along the thickness direction.

[0020] Preferably, the electrode has a side surface facing in a direction perpendicular to the thickness direction. [Effects of the Invention]

[0021] According to the above-described configuration, it is possible to prevent cracks from occurring at the bonding interface between the solder and the electrode in the semiconductor device.

[0022] Other features and advantages of the present disclosure will become more apparent from the following detailed description taken in conjunction with the accompanying drawings. [Brief explanation of the drawings]

[0023] [Figure 1] 1 is a perspective view of a semiconductor device according to a first embodiment. [Figure 2] FIG. 2 is a plan view (through a sealing resin) of the semiconductor device shown in FIG. [Figure 3] FIG. 2 is a plan view of the semiconductor device shown in FIG. 1 (with the semiconductor element and sealing resin transparent); [Figure 4] FIG. 2 is a bottom view of the semiconductor device shown in FIG. [Figure 5] FIG. 2 is a front view of the semiconductor device shown in FIG. [Figure 6] FIG. 2 is a rear view of the semiconductor device shown in FIG. [Figure 7] FIG. 2 is a right side view of the semiconductor device shown in FIG. [Figure 8] FIG. 2 is a left side view of the semiconductor device shown in FIG. [Figure 9] FIG. 9 is a cross-sectional view taken along line IX-IX in FIG. [Figure 10]FIG. 4 is a cross-sectional view taken along line XX in FIG. 3. [Figure 11] FIG. 4 is a cross-sectional view taken along line XI-XI in FIG. [Figure 12] FIG. 4 is a cross-sectional view taken along line XII-XII in FIG. 3. [Figure 13] FIG. 10 is an enlarged view of a portion of FIG. 9 (near the first electrode). [Figure 14] FIG. 14 is a partially enlarged cross-sectional view taken along line XIV-XIV in FIG. [Figure 15] FIG. 10 is an enlarged view of a portion of FIG. 9 (near the second electrode). [Figure 16] FIG. 4 is a partially enlarged cross-sectional view showing a first modified example of the semiconductor device according to the first embodiment. [Figure 17] FIG. 10 is a partially enlarged cross-sectional view showing a semiconductor device according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0024] Embodiments based on the present disclosure will be described with reference to the accompanying drawings.

[0025] A semiconductor device A10 according to a first embodiment will be described with reference to FIGS. 1 to 15. The semiconductor device A10 includes a plurality of first leads 10A, 10B, and 10C, a plurality of second leads 21, a pair of third leads 22, a semiconductor element 30, a conductive bonding material 70, and a sealing resin 40. As shown in FIG. 1, the package format of the semiconductor device A10 is not particularly limited, and in this embodiment, it is a QFN (Quad Flat Non-leaded) package. The applications and functions of the semiconductor device A10 are also not particularly limited. Applications of the semiconductor device A10 include electronic equipment, general industrial equipment, and automotive applications. Functions of the semiconductor device A10 include, for example, a DC / DC converter and an AC / DC converter. In this embodiment, the semiconductor device A10 configured as an automotive DC / DC converter will be described as an example. The semiconductor device A10 in the illustrated example has a square shape when viewed along the z direction (i.e., in a plan view), but the present disclosure is not limited thereto.

[0026] For ease of understanding, Fig. 2 is a perspective view through the sealing resin 40. For ease of understanding, Fig. 3 is a perspective view through the semiconductor element 30 and the sealing resin 40. In these figures, the semiconductor element 30 and the sealing resin 40 are shown by imaginary lines (two-dot chain lines). In this disclosure, the z direction is also referred to as the thickness direction. The x direction and the y direction are perpendicular to the z direction and perpendicular to each other.

[0027] As shown in FIG. 2, the multiple first leads 10A, 10B, and 10C, the multiple second leads 21, and the pair of third leads 22 support the semiconductor element 30 and serve as terminals for mounting the semiconductor device A10 on a wiring board. The multiple first leads 10A, 10B, and 10C, the multiple second leads 21, and the pair of third leads 22 are an example of a "conductive member." As shown in FIGS. 9 to 12, each of the multiple first leads 10A, 10B, and 10C, the multiple second leads 21, and the pair of third leads 22 is partially covered with a sealing resin 40. In FIGS. 1 and 4 to 8, multiple discrete points are drawn on the portions of the multiple first leads 10A, 10B, and 10C, the multiple second leads 21, and the pair of third leads 22 that are exposed from the sealing resin 40.

[0028] The constituent material of the plurality of first leads 10A, 10B, 10C, the plurality of second leads 21, and the pair of third leads 22 is, for example, Cu or a Cu alloy.

[0029] As shown in FIGS. 3 and 4, each of the multiple first leads 10A, 10B, and 10C has a strip shape extending in the x direction when viewed along the z direction. Each of the multiple first leads 10A, 10B, and 10C has a first main surface 101 and a first back surface 102 facing opposite sides in the z direction. The first main surface 101 faces one side in the z direction and faces the semiconductor element 30, and is an example of a "main surface." The first main surface 101 is covered with the sealing resin 40. The first back surface 102 faces the other side in the z direction. The first back surface 102 is exposed from the sealing resin 40 and is an example of a "back surface." In the first leads 10A, 10B, and 10C, the semiconductor element 30 is supported by the first main surface 101 of the main portion 11. 3 and 4, in the illustrated example, the area of ​​the first main surface 101 is larger than the area of ​​the first rear surface 102 in each of the first leads 10A, 10B, and 10C.

[0030] 3, the first lead 10A and the first lead 10B receive DC power (voltage) to be converted into power in the semiconductor device A10. In this embodiment, the first lead 10A is a positive electrode (P terminal). The first lead 10B is a negative electrode (N terminal). The first lead 10C outputs AC power (voltage) converted by a switching circuit 321 of the semiconductor element 30, which will be described later. The multiple first leads 10A, 10B, and 10C are arranged in the y direction from one side to the other in the order of first lead 10A, first lead 10C, and first lead 10B.

[0031] As shown in FIG. 3, the first lead 10A is located between the multiple second leads 21 and the first lead 10C in the y direction. The first lead 10C is located between the first lead 10A and the first lead 10B in the y direction. Each of the first lead 10A and the first lead 10C includes a main portion 11 and a pair of side portions 12. As shown in FIGS. 3 and 4, the main portion 11 extends in the x direction. The pair of side portions 12 are connected to both ends of the main portion 11 in the x direction and have a smaller y-direction dimension than the main portion 11. As shown in FIGS. 10 and 11, each of the pair of side portions 12 has a first end surface 121. The first end surface 121 is connected to both the first main surface 101 and the first back surface 102 and faces the x direction. The first end surface 121 is exposed from the sealing resin 40.

[0032] As shown in FIG. 3, the first lead 10B includes a main portion 11, a pair of side portions 12, and multiple protrusions 13. The multiple protrusions 13 protrude from the other side of the main portion 11 in the y direction. A sealing resin 40 is filled between two adjacent protrusions 13. Each of the multiple protrusions 13 has a minor end face 131. The minor end face 131 is connected to both the first main surface 101 and the first back surface 102 and faces the other side in the y direction. The minor end face 131 is exposed from the sealing resin 40. As shown in FIG. 7, the multiple minor end faces 131 are arranged at predetermined intervals along the x direction. The first leads 10A, 10B, and 10C are not limited to a shape having a main portion 11 and side portions 12, and may have other shapes.

[0033] In each of the first lead 10A, the first lead 10B, and the first lead 10C, the first rear surface 102, the pair of first end faces 121, and the plurality of sub-end faces 131 exposed from the sealing resin 40 may be plated with, for example, Sn (Sn). Instead of Sn plating, a plurality of metal platings, for example, Ni, Pd, and Au stacked in this order, may be employed.

[0034] As shown in FIG. 3, the multiple second leads 21 are located on one side of the first lead 10 in the y direction. One of the multiple second leads 21 is a ground terminal of a control circuit 322 of the semiconductor element 30, which will be described later. To each of the other multiple second leads 21, power (voltage) for driving the control circuit 322 or an electrical signal to be transmitted to the control circuit 322 is input. As shown in FIGS. 3 and 4, each of the multiple second leads 21 has a second main surface 211, a second back surface 212, and a second end surface 213. The shape of the second lead 21 is not particularly limited.

[0035] The second main surface 211 faces the same side in the z direction as the first main surface 101 of the first lead 10 and faces the semiconductor element 30. The second main surface 211 is covered with the sealing resin 40 and is an example of a "main surface." The semiconductor element 30 is supported by the second main surface 211. The second back surface 212 faces the opposite side from the second main surface 211. The second back surface 212 is exposed from the sealing resin 40 and is an example of a "back surface." The second end surface 213 is connected to both the second main surface 211 and the second back surface 212 and faces one side in the y direction. The second end surface 213 is exposed from the sealing resin 40. As shown in FIG. 8 , the multiple second end surfaces 213 are arranged at predetermined intervals along the x direction. The two second leads 21 arranged at both ends in the x direction further have fourth end surfaces 214. The fourth end surface 214 is a surface facing the x direction and is exposed from the sealing resin 40. In the illustrated example, as shown in Figures 3 and 4, the area of ​​the second main surface 211 of each of the multiple second leads 21 is larger than the area of ​​the second back surface 212.

[0036] For example, Sn plating may be applied to the second rear surfaces 212, the second end surfaces 213, and the fourth end surfaces 214 of the second leads 21 exposed from the sealing resin 40. Instead of Sn plating, for example, multiple metal platings in which Ni, Pd, and Au are stacked in this order may be used.

[0037] As shown in FIG. 3, the pair of third leads 22 are located between the first lead 10A and the plurality of second leads 21 in the y direction. The pair of third leads 22 are spaced apart from each other in the x direction. An electrical signal or the like is input to each of the pair of third leads 22 to be transmitted to a control circuit 322 configured in the semiconductor element 30. As shown in FIGS. 3 and 4, each of the pair of third leads 22 has a third main surface 221, a third back surface 222, and a third end surface 223. The shape of the third lead 22 is not particularly limited.

[0038] The third main surface 221 faces the same side in the z direction as the first main surface 101 of the first lead 10 and faces the semiconductor element 30. The third main surface 221 is covered with the sealing resin 40 and is an example of a "main surface." The semiconductor element 30 is supported by the third main surface 221. The third back surface 222 faces the opposite side from the third main surface 221. The third back surface 222 is exposed from the sealing resin 40 and is an example of a "back surface." The third end surface 223 is connected to both the third main surface 221 and the third back surface 222 and faces the x direction. The third end surface 223 is exposed from the sealing resin 40. The third end surface 223 is arranged along the y direction, along with the respective regions of the first end surfaces 121 of the first lead 10. In the illustrated example, in each of a pair of third leads 22, the area of ​​the third main surface 221 is larger than the area of ​​the third back surface 222.

[0039] For example, Sn plating may be applied to the third rear surfaces 222 and the third end surfaces 223 of the pair of third leads 22 exposed from the sealing resin 40. Instead of Sn plating, a configuration having multiple metal plating layers, for example, Ni, Pd, and Au laminated in this order, may be used.

[0040] As shown in FIGS. 9 to 15, the semiconductor element 30 is supported by a plurality of first leads 10A, 10B, and 10C, a plurality of second leads 21, and a pair of third leads 22. The semiconductor element 30 is covered with a sealing resin 40. The semiconductor element 30 has a semiconductor substrate 31, a semiconductor layer 32, a plurality of first electrodes 33A, a plurality of second electrodes 33B, a passivation film 34, and a surface protection film 35. The plurality of first electrodes 33A and the plurality of second electrodes 33B are examples of "electrodes." The semiconductor element 30 is a flip-chip type LSI having a circuit configured therein.

[0041] The semiconductor element 30 has an element first surface 30a and an element second surface 30b. The element first surface 30a faces, in the z direction, first main surfaces 101 of the multiple first leads 10A, 10B, and 10C, second main surfaces 211 of the multiple second leads 21, and third main surfaces 221 of the pair of third leads 22. The element second surface 30b faces the opposite side to the element first surface 30a in the z direction.

[0042] 13 to 15, a semiconductor layer 32, a first electrode 33A, a second electrode 33B, a passivation film 34, and a surface protection film 35 are provided below a semiconductor substrate 31. The semiconductor substrate 31 is made of, for example, silicon (Si) or silicon carbide (SiC). In this embodiment, one surface of the semiconductor substrate 31 constitutes the second element surface 30b.

[0043] As shown in FIGS. 9 to 12, the semiconductor layer 32 is stacked on the semiconductor substrate 31 on a side facing the first main surface 101 of the first lead 10 in the z direction. In this embodiment, one surface of the semiconductor layer 32 constitutes the first element surface 30a. The semiconductor layer 32 includes multiple types of p-type and n-type semiconductors based on differences in the amounts of doped elements. The semiconductor layer 32 includes a switching circuit 321 and a control circuit 322 that is electrically connected to the switching circuit 321. The switching circuit 321 is, for example, a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) or an IGBT (Insulated Gate Bipolar Transistor). In the example shown in semiconductor device A10, the switching circuit 321 is divided into two regions: a high-voltage region (upper arm circuit) and a low-voltage region (lower arm circuit). Each region is composed of one n-channel MOSFET. The control circuit 322 includes a gate driver for driving the switching circuit 321, a bootstrap circuit corresponding to the high-voltage region of the switching circuit 321, and the like, and performs control for normally driving the switching circuit 321. A wiring layer (not shown) is also formed in the semiconductor layer 32. The wiring layer provides mutual conduction between the switching circuit 321 and the control circuit 322.

[0044] 13 to 15, a plurality of pads 329 are provided on the semiconductor layer 32. The pads 329 are in contact with a wiring layer formed on the semiconductor layer 32. As a result, the pads 329 are electrically connected to either the switching circuit 321 or the control circuit 322 of the semiconductor layer 32. The pads 329 are made of, for example, an Al layer or a plurality of metal layers stacked in this order from the semiconductor layer 32 downwards in the form of Cu, Ni, and Pd.

[0045] As shown in FIGS. 13 to 15, the passivation film 34 covers the lower surface of the semiconductor layer 32 and portions of each of the pads 329. The passivation film 34 has electrical insulation properties. The passivation film 34 is made of, for example, a silicon oxide film (SiO2) that contacts the lower surface of the semiconductor layer 32 and portions of the pads 329, and a silicon nitride film (Si3N4) that is laminated on the silicon oxide film. The passivation film 34 has a plurality of openings 341. Portions of the pads 329 are exposed through the openings 341. The configuration of the passivation film 34 is not particularly limited.

[0046] 13 to 15, the surface protective film 35 covers the passivation film 34. In the illustrated example, each of the plurality of first electrodes 33A and the plurality of second electrodes 33B is in contact with the surface protective film 35. The surface protective film 35 has electrical insulation properties. The surface protective film 35 is made of a material such as polyimide. The configuration of the surface protective film 35 is not particularly limited.

[0047] 9 to 12, the plurality of first electrodes 33A and the plurality of second electrodes 33B are provided on the element first surface 30a side in the z direction, and protrude toward the first main surface 101, the second main surface 211, and the third main surface 221. The constituent material of the first electrodes 33A and the second electrodes 33B contains Cu, for example, Cu or a Cu alloy. In this embodiment, the plurality of first electrodes 33A and the plurality of second electrodes 33B are in contact with a plurality of pads 329.

[0048] The multiple first electrodes 33A are electrically connected to the switching circuit 321 of the semiconductor layer 32. The multiple first electrodes 33A are also connected to the first main surfaces 101 of the multiple first leads 10A, 10B, and 10C. This electrically connects the multiple first leads 10A, 10B, and 10C to the switching circuit 321. The shape of the first electrode 33A as viewed along the z direction is not particularly limited, and may be, for example, a circle, an oval, a rectangle, or a polygon. In the illustrated example, the first electrode 33A has an oval shape as viewed along the z direction. The dimensions of the first electrode 33A are not particularly limited, and for example, as shown in FIGS. 13 and 14 , the major axis D1 is, for example, 300 μm, the minor axis D2 is, for example, 100 μm, and the height H is, for example, 50 μm. In this case, the ratio of the height H to the major diameter D1 is 1:6, and the ratio of the height H to the minor diameter D2 is 1:2. The present disclosure is not limited to this, and the ratio of the height H to the major diameter D1 or the minor diameter D2 is, for example, 1:2 to 10.

[0049] The second electrodes 33B are electrically connected to the control circuit 322 of the semiconductor layer 32. Most of the second electrodes 33B are connected to the second main surfaces 211 of the second leads 21, and the remainder are connected to the third main surfaces 221 of the pair of third leads 22. This electrically connects the second leads 21 and the pair of third leads 22 to the control circuit 322. The shape of the second electrodes 33B as viewed in the z direction is not particularly limited, and may be a circle, an oval, a rectangle, a polygon, or the like, as appropriate. In the illustrated example, the second electrodes 33B are circular as viewed in the z direction. The dimensions of the second electrodes 33B are not particularly limited, and as an example, the diameter D3 is 100 μm, and the height H is 50 μm, as shown in FIG. 15. The ratio of the height H to the diameter D3 is, for example, 1:2 to 1:10.

[0050] As shown in FIGS. 13 to 15 , each of the plurality of first electrodes 33A and the plurality of second electrodes 33B has a tip surface 331 and a side surface 332. The tip surface 331 is located at the tip of the first electrode 33A and the second electrode 33B in the z direction and faces the side opposite to the first main surface 101, the second main surface 211, and the third main surface 221. The tip surface 331 is located closer to the first main surface 101, the second main surface 211, and the third main surface 221 than the surface protection film 35 in the z direction. The side surface 332 extends from the tip surface 331 toward the pad 329 (semiconductor layer 32) in the z direction and faces in a direction perpendicular to the z direction (for example, the x direction or the y direction) as a whole. The side surface 332 is in contact with the sealing resin 40. The shapes of the tip surface 331 and the side surface 332 are not particularly limited. The tip surface 331 and the side surface 332 may be curved or bent, or may have a recess or the like formed thereon.

[0051] As shown in FIGS. 13 to 15 , the conductive bonding material 70 is interposed between any one of the first main surfaces 101 of the plurality of first leads 10A, 10B, and 10C, the second main surfaces 211 of the plurality of second leads 21, and the third main surface 221 of the third lead 22, and any one of the plurality of first electrodes 33A and the plurality of second electrodes 33B, thereby conducting them together. The conductive bonding material 70 is conductive. In the example of the semiconductor device A10, examples of the conductive bonding material 70 include solder containing Sn, solder containing indium, sintered Ag, and Ag paste. In this embodiment, a case where the conductive bonding material 70 is solder containing Sn will be described as an example.

[0052] As shown in FIGS. 13 to 15 , the first barrier layer 50 is interposed between either the first electrode 33A or the second electrode 33B and the conductive bonding material 70, thereby electrically connecting them. The first barrier layer 50 functions to suppress a chemical reaction between the first electrode 33A or the second electrode 33B and the conductive bonding material 70. The material of the first barrier layer 50 is not particularly limited, and a metal capable of suppressing the chemical reaction may be appropriately selected, such as Ni or Fe. When the first electrode 33A and the second electrode 33B contain Cu and the conductive bonding material 70 contains Sn, a preferred material for the first barrier layer 50 is Ni. The thickness of the first barrier layer 50 is, for example, 0.3 μm to 5.0 μm, and preferably 0.5 μm to 3.0 μm.

[0053] In this embodiment, the first barrier layer 50 is in contact with the tip surfaces 331 of the first electrode 33A and the second electrode 33B and is formed on the tip surfaces 331 by, for example, plating. Another conductive layer may be further provided between the tip surfaces 331 and the first barrier layer 50. In this embodiment, the first barrier layer 50 is in contact with the conductive bonding material 70. In this case, for example, a layer containing Sn is formed on the first barrier layer 50 by plating, and when the semiconductor element 30 is mounted on the first leads 10A, 10B, and 10C, the second lead 21, and the third lead 22, the conductive bonding material 70 is formed through a molten state. Another conductive layer of a different composition may be further provided between the first barrier layer 50 and the conductive bonding material 70.

[0054] As shown in FIGS. 13 to 15 , the second barrier layer 60 is interposed between the conductive bonding material 70 and any of the first main surfaces 101 of the first leads 10A, 10B, and 10C, the second main surfaces 211 of the second leads 21, and the third main surface 221 of the third lead 22, thereby providing electrical continuity between them. The second barrier layer 60 functions to suppress chemical reactions between the first leads 10A, 10B, and 10C, the second leads 21, and the third leads 22 and the conductive bonding material 70. The material of the second barrier layer 60 is not particularly limited, and a metal capable of suppressing chemical reactions may be appropriately selected, such as Ni or Fe. In the illustrated example, the second barrier layer 60 is provided to cover portions of the first main surface 101, the second main surface 211, and the third main surface 221, but does not entirely cover the first main surface 101, the second main surface 211, and the third main surface 221.

[0055] In this embodiment, the second barrier layer 60 has a base layer 61 and an auxiliary layer 62. The base layer 61 is interposed between the auxiliary layer 62 and any of the first main surfaces 101 of the multiple first leads 10A, 10B, and 10C, the second main surfaces 211 of the multiple second leads 21, and the third main surface 221 of the third lead 22. The base layer 61 is made of, for example, Ni. The auxiliary layer 62 is stacked on the side of the base layer 61 opposite to the first main surfaces 101 of the multiple first leads 10A, 10B, and 10C, the second main surfaces 211 of the multiple second leads 21, and the third main surface 221 of the third lead 22. In the illustrated example, the auxiliary layer 62 has a first layer 621 and a second layer 622. The first layer 621 is stacked on the base layer 61. The second layer 622 is stacked on the first layer 621. The material of the first layer 621 is not particularly limited, and may include, for example, Pd. The material of the second layer 622 is not particularly limited, and may include, for example, Au.

[0056] The thicknesses of base layer 61 and auxiliary layer 62 are not particularly limited. As an example of these thicknesses, base layer 61 has a thickness of, for example, 0.3 μm to 5.0 μm, and preferably 0.5 μm to 3.0 μm. First layer 621 of auxiliary layer 62 has a thickness of, for example, 0.02 μm to 0.2 μm. Second layer 622 has a thickness of, for example, 0.003 μm to 0.01 μm.

[0057] In this embodiment, the second barrier layer 60 is in contact with the first main surface 101, the second main surface 211, and the third main surface 221. Another conductive layer may be provided between the second barrier layer 60 and the first main surface 101, the second main surface 211, and the third main surface 221. In this embodiment, the second barrier layer 60 is in contact with the conductive bonding material 70. Another conductive layer may be provided between the second barrier layer 60 and the conductive bonding material 70.

[0058] The shapes of the first barrier layer 50 and the second barrier layer 60 as viewed along the z direction are not particularly limited. In the examples shown in FIGS. 2, 3, 13, and 14, the first barrier layer 50 and the second barrier layer 60 corresponding to the first electrode 33A are all oval when viewed along the z direction. On the other hand, as shown in FIGS. 2, 3, and 15, the first barrier layer 50 and the second barrier layer 60 corresponding to the second electrode 33B are all circular when viewed along the z direction. As shown in FIGS. 13 to 15, in this embodiment, the size of the second barrier layer 60 as viewed along the z direction is larger than the shape of the first barrier layer 50 as viewed along the z direction. As viewed along the z direction, the first barrier layer 50 is enclosed within the second barrier layer 60. In the illustrated example, the second barrier layer 60 has a second layer 622, and the second layer 622 has relatively good wettability with respect to the conductive bonding material 70. In this case, the conductive bonding material 70 has a shape in which the cross-sectional area perpendicular to the z direction increases from the first barrier layer 50 toward the second barrier layer 60 in the z direction.

[0059] 5 to 8, the sealing resin 40 has a top surface 41, a bottom surface 42, a pair of first side surfaces 431, and a pair of second side surfaces 432. The sealing resin 40 is made of, for example, a black epoxy resin.

[0060] 9 to 12, the top surface 41 faces the same side in the z direction as the first main surfaces 101 of the multiple first leads 10A, 10B, and 10C. As shown in FIGS. 5 to 8, the bottom surface 42 faces the opposite side to the top surface 41. As shown in FIG. 4, the first rear surfaces 102 of the multiple first leads 10A, 10B, and 10C, the second rear surfaces 212 of the multiple second leads 21, and the third rear surfaces 222 of the pair of third leads 22 are exposed from the bottom surface 42.

[0061] 7 and 8, the pair of first side surfaces 431 are connected to both the top surface 41 and the bottom surface 42 and face in the x direction. The pair of first side surfaces 431 are spaced apart from each other in the y direction. As shown in FIGS. 10 to 12, the first end surfaces 121 of the plurality of first leads 10A, 10B, and 10C, the fourth end surface 214 of the second lead 21, and the third end surface 223 of the third lead 22 are exposed from each of the pair of first side surfaces 431 so as to be flush with the first side surfaces 431.

[0062] As shown in FIGS. 5 and 6 , the pair of second side surfaces 432 are connected to all of the top surface 41, the bottom surface 42, and the pair of first side surfaces 431 and face in the y direction. The pair of second side surfaces 432 are spaced apart in the x direction. As shown in FIG. 9 , the second end surfaces 213 of the multiple second leads 21 are exposed from the second side surface 432 located on one side in the y direction so as to be flush with the second side surface 432. The multiple minor end surfaces 131 of the first lead 10B are exposed from the second side surface 432 located on the other side in the y direction so as to be flush with the second side surface 432.

[0063] The effects of the semiconductor device A10 will be described below.

[0064] In this embodiment, a first barrier layer 50 is interposed between the first electrode 33A and the second electrode 33B and the conductive bonding material 70. Unlike this embodiment, for example, in a configuration in which the first electrode 33A and the second electrode 33B are in contact with the conductive bonding material 70, a chemical reaction between Cu contained in the first electrode 33A and the second electrode 33B and Sn contained in the conductive bonding material 70 may occur, resulting in the formation of voids known as Kirkendall voids at the bonding interfaces between the first electrode 33A and the second electrode 33B and the conductive bonding material 70. The presence of such voids may lead to cracks originating from the voids, for example, when thermal stress occurs in the semiconductor device A10. According to this embodiment, the chemical reaction between the first electrode 33A and the second electrode 33B and the conductive bonding material 70 is suppressed by the first barrier layer 50. This suppresses the formation of voids at the bonding interfaces between the first electrode 33A and the second electrode 33B and the conductive bonding material 70, thereby reducing the occurrence of cracks.

[0065] When the first electrode 33A and the second electrode 33B contain Cu and the conductive bonding material 70 contains Sn, it is preferable that the first barrier layer 50 contains Ni in order to suppress a chemical reaction between the first electrode 33A and the second electrode 33B and the conductive bonding material 70.

[0066] The first barrier layer 50 is preferably in contact with the front end surfaces 331 of the first electrode 33A and the second electrode 33B in order to suppress the chemical reaction. The second barrier layer 60 is preferably in contact with the conductive bonding material 70 in order to suppress the chemical reaction.

[0067] In this embodiment, a second barrier layer 60 is interposed between the first leads 10A, 10B, 10C, the second lead 21, and the third lead 22 and the conductive bonding material 70. Unlike this embodiment, in a configuration in which the first leads 10A, 10B, 10C, the second lead 21, and the third lead 22 are in contact with the conductive bonding material 70, for example, a chemical reaction may occur between Cu contained in the first leads 10A, 10B, 10C, the second lead 21, and the third lead 22 and Sn contained in the conductive bonding material 70, resulting in voids called Kirkendall voids at the bonding interfaces between the first leads 10A, 10B, 10C, the second lead 21, and the third lead 22 and the conductive bonding material 70. The presence of such voids raises concerns that cracks may originate from the voids. According to this embodiment, the chemical reaction between the first leads 10A, 10B, 10C, the second lead 21, and the third lead 22 and the conductive bonding material 70 is suppressed by the second barrier layer 60. This prevents voids from being generated at the bonding interfaces between the first leads 10A, 10B, 10C, the second lead 21, and the third lead 22 and the conductive bonding material 70, thereby reducing the occurrence of cracks.

[0068] When the first leads 10A, 10B, 10C, the second lead 21, and the third lead 22 contain Cu and the conductive bonding material 70 contains Sn, it is preferable for the second barrier layer 60 to contain Ni in order to suppress a chemical reaction between the first leads 10A, 10B, 10C, the second lead 21, and the third lead 22 and the conductive bonding material 70. It is preferable for the second barrier layer 60 to have a base layer 61 containing Ni, and for this base layer 61 to be formed directly on the first main surface 101, the second main surface 211, and the third main surface 221 in order to suppress a chemical reaction. It is preferable for the second barrier layer 60 to be in contact with the conductive bonding material 70 in order to suppress a chemical reaction.

[0069] The second barrier layer 60 has a first layer 621 and a second layer 622. The first layer 621 contains Au, which improves the wettability of the second barrier layer 60 with the molten conductive bonding material 70. This allows the conductive bonding material 70 to be provided over a wider area. The second barrier layer 60 is larger than the first barrier layer 50 when viewed along the z direction, which allows the conductive bonding material 70 to be in contact with wider areas on the first principal surface 101, second principal surface 211, and third principal surface 221 sides relative to the sizes of the first electrode 33A and the second electrode 33B.

[0070] 16 and 17 show modifications and other embodiments of the present disclosure, in which elements that are the same as or similar to those in the above-described embodiments are given the same reference numerals.

[0071] 16 shows a first modified example of the semiconductor device A10. In the semiconductor device A11 of this modified example, the second barrier layer 60 is composed of a single layer. Specifically, the second barrier layer 60 is composed of a single layer made of, for example, Ni.

[0072] This modification also makes it possible to suppress the occurrence of cracks at the bonding interface. As can be seen from this modification, the second barrier layer 60 is not limited to a configuration made up of multiple types of layers.

[0073] 17 shows a semiconductor device according to the second embodiment. The semiconductor device A20 of this embodiment differs from the first embodiment in that it does not include the second barrier layer 60.

[0074] In this embodiment, the conductive bonding material 70 is in contact with the first main surface 101. Alternatively, a plating layer may be provided on the first main surface 101. When the conductive bonding material 70 is in contact with the first main surface 101, the bonding area between the conductive bonding material 70 and the first main surface 101 may be smaller than the bonding area between the conductive bonding material 70 and the second barrier layer 60 in the above-described embodiment.

[0075] In this embodiment as well, the mobile reaction between the first electrode 33A and the second electrode 33B and the conductive bonding material 70 can be suppressed by the first barrier layer 50. As can be understood from this embodiment, depending on the use environment and operating conditions of the semiconductor device A20, a configuration without the second barrier layer 60 may be adopted.

[0076] The present disclosure is not limited to the above-described embodiment and modifications, and the specific configuration of each part of the present disclosure can be freely modified in various ways. [Explanation of symbols]

[0077] A10, A11, A20: Semiconductor device 10, 10A, 10B, 10C: 1st lead 11: Main section 12: Side 13:Protrusion 21: Second lead 22: Third lead 30: Semiconductor element 30a: First element surface 30b: Second element surface 31: Semiconductor substrate 32: Semiconductor layer 33A: 1st electrode 33B: 2nd electrode 34: Passivation film 35: Surface protective film 40: Sealing resin 41:Top surface 42: Bottom 50: First barrier layer 60: Second barrier layer 61: Base layer 62: Auxiliary layer 70: Conductive adhesive 101: First main surface 102: First back side 121: First end surface 131: Minor end face 211: Second main surface 212: Second back side 213: Second end surface 214: 4th end face 221: Third main surface 222: Third reverse side 223: Third end surface 321: Switching circuit 322: Control circuit 329: Pad 331:Tip surface 332: Side 341 :Aperture 431 :1st side 432:Second side 621 :1st layer 622 :2nd layer

Claims

1. a semiconductor element having a first surface and a second surface facing opposite to each other in a thickness direction, and an electrode provided on the first surface side; a conductive member having a main surface facing the first surface of the element and a back surface facing the opposite side to the main surface; a conductive bonding material interposed between the electrode and the main surface of the conductive member; a resin portion that covers at least a portion of the conductive member, the semiconductor element, and the conductive bonding material; a first barrier layer interposed between the electrode and the conductive bonding material and configured to suppress a chemical reaction between the electrode and the conductive bonding material; a surface protection film interposed between the first surface of the element and the resin portion and covering a part of the electrode; A semiconductor device comprising:

2. a semiconductor element having a first surface and a second surface facing opposite to each other in a thickness direction, and a plurality of electrodes provided on the first surface; a conductive member having a main surface facing the first surface of the element and a back surface facing the opposite side to the main surface; a conductive bonding material interposed between the electrode and the main surface of the conductive member; a resin portion that covers at least a portion of the conductive member, the semiconductor element, and the conductive bonding material; a first barrier layer interposed between the electrode and the conductive bonding material and configured to suppress a chemical reaction between the electrode and the conductive bonding material; a surface protection film interposed between the element first surface and the resin portion, Each of the electrodes is in contact with the surface protection film, the plurality of electrodes are arranged in a plurality of rows, each row extending along a second direction and spaced apart from one another in a first direction perpendicular to the second direction; The semiconductor device, wherein the electrodes included in two adjacent rows in the first direction are located at different positions in the second direction.

3. The semiconductor device according to claim 1 , wherein the electrode contains Cu.

4. 4. The semiconductor device according to claim 1, wherein said conductive member contains Cu.

5. 5. The semiconductor device according to claim 1, wherein said first barrier layer contains Ni.

6. 6. The semiconductor device according to claim 1, wherein the conductive bonding material contains Sn.

7. 7. The semiconductor device according to claim 1, wherein said electrode and said first barrier layer are in contact with each other.

8. 8. The semiconductor device according to claim 1, wherein said conductive bonding material and said first barrier layer are in contact with each other.

9. 9. The semiconductor device according to claim 1, further comprising a second barrier layer interposed between said conductive member and said conductive bonding material, said second barrier layer suppressing a chemical reaction between said conductive member and said conductive bonding material.

10. The semiconductor device according to claim 9 , wherein the second barrier layer contains Ni.

11. 11. The semiconductor device according to claim 9, wherein the second barrier layer includes a base layer and an auxiliary layer interposed between the conductive bonding material and the base layer.

12. 12. The semiconductor device according to claim 9, wherein the conductive member and the second barrier layer are in contact with each other.

13. 13. The semiconductor device according to claim 9, wherein the conductive bonding material and the second barrier layer are in contact with each other.

14. 14. The semiconductor device according to claim 9, wherein the second barrier layer has a length in a direction perpendicular to the thickness direction that is greater than that of the first barrier layer.

15. 15. The semiconductor device according to claim 1, wherein said electrode has a side surface facing in a direction perpendicular to said thickness direction.

Images