Lead frame and semiconductor device

Abstract

A lead frame (1) is provided with: heat dissipation plates (10) each having a mounting surface (11) on which a semiconductor element (30) is mounted; and a unit lead frame (20) having leads (21). The heat dissipation plates each have first groove parts (13) formed in peripheral portions of the corresponding mounting surface (11). The unit lead frame (20) has protrusions (22) which have, at the tips (22a) thereof, shapes corresponding to the first groove parts (13). The protrusions (22) fit into the first groove parts (13), and thereby the heat dissipation plates (10) are fixed to the unit lead frame (20).

Description

Lead frame and semiconductor device

[0001] The present disclosure relates to a lead frame and a semiconductor device.

[0002] For example, in a semiconductor device that incorporates a semiconductor element that controls a large current, such as a power semiconductor element, a heat sink is bonded to the lead frame body in order to efficiently dissipate the heat generated by the semiconductor element, and the semiconductor element is placed directly on the heat sink.

[0003] Japanese Patent Application Publication No. 2001-144242

[0004] Conventionally, the lead frame body and the heat sink are joined by crimping, which requires a large area for the crimping process, which means that extra space is required inside the semiconductor device for the crimping process, which can be a disadvantage in manufacturing the semiconductor device.

[0005] An object of the present disclosure is to provide a lead frame and a semiconductor device that require a small area for bonding the lead frame body and the heat sink.

[0006] A lead frame according to one aspect of the embodiment includes a heat sink having a mounting surface on which a semiconductor element is mounted, and a unit lead frame having leads. The heat sink has a first groove formed in the periphery of the mounting surface. The unit lead frame has a protrusion whose tip has a shape corresponding to the first groove. The protrusion fits into the first groove, thereby fixing the heat sink to the unit lead frame.

[0007] A semiconductor device according to one aspect of the embodiment includes the lead frame and a semiconductor element mounted on the mounting surface.

[0008] According to one aspect of the embodiment, the area required for bonding the lead frame body and the heat sink is small. Note that the effects described herein are not necessarily limited to those described herein, and may be any of the effects described in this disclosure.

[0009] FIG. 1A is a plan view and a side view showing an example of a heat sink according to an embodiment. FIG. 1B is an enlarged plan view showing an example of a lead frame main body according to an embodiment. FIG. 2A is an enlarged plan view showing an example of a lead frame according to an embodiment. FIG. 2B is a cross-sectional view taken along line A-A in FIG. 2A. FIG. 3A is an enlarged plan view showing an example of a bonding region between a heat sink and a unit lead frame according to an embodiment. FIG. 3B is a cross-sectional view taken along line B-B in FIG. 3A. FIG. 4A is a plan view showing an example of a semiconductor device according to an embodiment. FIG. 4B is a cross-sectional view taken along line C-C in FIG. 4A. FIG. 5A is an enlarged cross-sectional view showing an example of a bonding region between a heat sink and a unit lead frame according to a first modification of the embodiment. FIG. 5B is an enlarged plan view showing an example of a bonding region between a heat sink and a unit lead frame according to a second modification of the embodiment. FIG. 6A is an enlarged plan view showing an example of a bonding region between a heat sink and a unit lead frame according to a third modification of the embodiment. FIG. 6B is an enlarged plan view showing another example of a bonding region between a heat sink and a unit lead frame according to the third modification of the embodiment. Fig. 7A is an enlarged plan view showing an example of a bonding region between a heat sink and a unit lead frame according to Modification 4 of the embodiment. Fig. 7B is an enlarged plan view showing an example of a bonding region between a heat sink and a unit lead frame according to Modification 5 of the embodiment. Fig. 8A is an enlarged plan view showing an example of a bonding region between a heat sink and a unit lead frame according to Modification 6 of the embodiment. Fig. 8B is an enlarged plan view showing an example of a bonding region between a heat sink and a unit lead frame according to Modification 7 of the embodiment.

[0010] The lead frame and semiconductor device disclosed in the present application will be described below with reference to the accompanying drawings. Note that the present disclosure is not limited to the following embodiments.

[0011] It should be noted that the drawings are schematic and that the dimensional relationships and ratios of elements may differ from reality. Furthermore, the drawings may contain parts whose dimensional relationships and ratios differ from one another.

[0012] <Heat Sink> First, a heat sink 10 forming the lead frame 1 (see FIG. 2A) according to the embodiment will be described with reference to FIG. 1A. FIG. 1A is a plan view and a side view showing an example of the heat sink 10 according to the embodiment.

[0013] The heat sink 10 functions as a die pad for a semiconductor device 100 (see FIG. 4A ), which will be described later. As shown in FIG. 1A , the heat sink 10 according to the embodiment is flat. One of the main surfaces of the heat sink 10 is a mounting surface 11, on which a semiconductor element 30 (see FIG. 4A ) is mounted. The main surface of the heat sink 10 opposite the mounting surface 11 is referred to as a back surface 12.

[0014] The heat sink 10 has, for example, a rectangular shape in a plan view. In the heat sink 10, first grooves 13 are formed in the peripheral portions of the mounting surface 11 that contact two opposing sides. The two first grooves 13 are formed, for example, at positions that are point-symmetrical with respect to the center X1 of the heat sink 10. The first grooves 13 have, for example, a rectangular parallelepiped shape cut out from the peripheral portion of the mounting surface 11, and may be formed by pressing or etching.

[0015] The heat sink 10 is made of a metal with good thermal conductivity, such as copper or a copper alloy, etc. The heat sink 10 is not limited to a rectangular shape in plan view, and may have a wide variety of planar shapes.

[0016] <Lead frame body> Next, the lead frame body 20 forming the lead frame 1 (see FIG. 2A) according to the embodiment will be described with reference to FIG. 1B. FIG. 1B is an enlarged plan view showing an example of the lead frame body 20 according to the embodiment.

[0017] The lead frame body 20 according to the embodiment is a member in which a predetermined pattern is formed by pressing or etching a metal plate made of copper, a copper alloy, an iron-nickel alloy, or the like.

[0018] The lead frame body 20 according to the embodiment has, for example, a band shape in a plan view. The lead frame body 20 is formed with a plurality of unit lead frames 20A arranged along the longitudinal direction. Note that in the present disclosure, the lead frame body 20 may be formed with a plurality of unit lead frames 20A arranged not only along the longitudinal direction but also along the width direction.

[0019] 1B, each unit lead frame 20A has a plurality of leads 21 and a plurality of protrusions 22. Adjacent unit lead frames 20A are connected to each other by a connecting bar 23.

[0020] The leads 21 function as connection terminals of the semiconductor device 100 (see FIG. 4A). The leads 21 are located, for example, around a central portion X2 of the unit lead frame 20A. The leads 21 are supported on the connecting bar 23 by, for example, a dam bar 24.

[0021] The protrusions 22 are supported by, for example, the connecting bars 23 and extend from the connecting bars 23 toward the inside of the unit lead frame 20A (for example, toward the central portion X2). For example, one protrusion 22 is provided on each of the connecting bars 23 on both sides that contact one unit lead frame 20A.

[0022] The tip 22a (see FIG. 3A) of the protrusion 22 has a shape corresponding to the first groove 13 (see FIG. 1A) of the heat sink 10 (see FIG. 1A) in a plan view.

[0023] The pilot holes 25 are formed side by side on both sides of the band-shaped lead frame body 20. The pilot holes 25 are used to position the lead frame body 20 and the lead frame 1 in various processes.

[0024] <Lead Frame> Next, a detailed configuration of the lead frame 1 according to the embodiment will be described with reference to Figures 2A to 3B. Figure 2A is an enlarged plan view showing an example of the lead frame 1 according to the embodiment. Figure 2B is a cross-sectional view taken along line AA in Figure 2A.

[0025] The lead frame 1 according to the embodiment has, for example, a band shape in a plan view, and is formed with a plurality of unit lead frame structures 1A arranged along the longitudinal direction. Each unit lead frame structure 1A corresponds to one of the semiconductor devices 100 (see FIG. 4A ) manufactured using the lead frame 1.

[0026] Adjacent unit lead frame structures 1A are connected to each other by connecting bars 23. In the present disclosure, a plurality of unit lead frame structures 1A may be formed side by side not only along the longitudinal direction of the lead frame 1 but also along the width direction.

[0027] 2A, the unit lead frame structure 1A has a heat sink 10 and a unit lead frame 20A. In the unit lead frame structure 1A, for example, the center X1 of the heat sink 10 (see FIG. 1A) is located at the same position as or close to the center X2 of the unit lead frame 20A (see FIG. 1B) in a plan view.

[0028] In the unit lead frame structure 1A, the leads 21 and the protrusions 22 are located around the heat sink 10, for example.

[0029] Here, in an embodiment, as shown in Figures 2A and 2B, the tip portion 22a of the protrusion portion 22 on the unit lead frame 20A may be fitted into the first groove portion 13 of the heat sink 10, thereby fixing the heat sink 10 to the unit lead frame 20A.

[0030] This reduces the area required for joining the lead frame body 20 and the heat sink 10 compared to when the heat sink 10 is fixed to the lead frame body 20 by caulking.

[0031] For example, when a semiconductor element 30 (see Figure 4A) of the same specifications is mounted on the heat sink 10, the width of the bonding area between the lead frame body 20 and the heat sink 10 required in the crimping process of the conventional technology was 2.11 mm, whereas in the present disclosure, the width of the required bonding area is reduced to 0.55 mm.

[0032] Furthermore, in the conventional crimping process, the heat sink 10 needs to be pressed to form a large convex shape, thereby forming the embossment required for the crimping process. However, in the embodiment, the first groove portion 13 is formed in the heat sink 10 by ordinary pressing or etching.

[0033] That is, in the embodiment, when the heat sink 10 is manufactured by various press processes, etching processes, or the like, the first groove portion 13 is formed in the heat sink 10, so that the manufacturing process of the heat sink 10 is simplified.

[0034] Furthermore, in the conventional crimping process, the heat sink 10 is pressed to form the embossments required for the crimping process, and therefore recesses are formed in the rear surface 12 of the heat sink 10 at positions corresponding to the embossments. As a result, in the conventional process, the effective area of ​​the rear surface 12, which is the heat dissipation surface of the semiconductor device 100, is reduced, which can result in a deterioration in the heat dissipation characteristics of the semiconductor device 100.

[0035] On the other hand, in the lead frame 1 according to the embodiment, as shown in FIG. 2B, the heat sink 10 can be formed so that the entire back surface 12 of the heat sink 10 is flat, thereby improving the heat dissipation characteristics of the semiconductor device 100.

[0036] In addition, in the embodiment, one heat sink 10 may be fixed to the unit lead frame 20A by fitting the multiple protrusions 22 into the multiple first grooves 13, respectively. This increases the number of fixing points between the heat sink 10 and the unit lead frame 20A, so that the heat sink 10 is stably fixed to the unit lead frame 20A.

[0037] Therefore, according to the embodiment, when the semiconductor device 100 is manufactured, the heat sink 10 is unlikely to come off the unit lead frame 20A, and the semiconductor device 100 can be manufactured stably.

[0038] 1A to 2B show an example in which one unit lead frame structure 1A is provided with two first grooves 13 and two protrusions 22, but the present disclosure is not limited to such an example. For example, one unit lead frame structure 1A may be provided with one first groove 13 and one protrusion 22, or three or more first grooves 13 and three or more protrusions 22 may be formed in one unit lead frame structure 1A.

[0039] Furthermore, the two first groove portions 13 may be positioned at positions that are point-symmetrical with respect to the center X1 ( FIG. 1A ) of the heat sink 10. This allows the heat sink 10 to be fixed to the unit lead frame 20A without bias, thereby ensuring stable manufacturing of the semiconductor device 100.

[0040] 2B , the protrusion 22 may have a bent portion 22 b, which is located closer to the base end of the protrusion 22 than the tip portion 22 a and bent toward one of the main surfaces of the unit lead frame 20A (the back surface 12 in FIG. 2B ).

[0041] As a result, the tip end 22a of the protrusion 22 and the lead 21 (see FIG. 2A ) are not flush with each other, making it difficult for the heat sink 10 to be flush with the lead 21. That is, in the embodiment, even when the heat sink 10 and the lead 21 overlap in plan view as shown in FIG. 2A , the heat sink 10 and the lead 21 are unlikely to come into contact with each other.

[0042] Therefore, according to the embodiment, the heat sink 10 may be formed larger because the heat sink 10 and the leads 21 are less likely to short-circuit, thereby improving the heat dissipation characteristics of the semiconductor device 100.

[0043] 3A is an enlarged plan view showing an example of a bonding region (Y portion in FIG. 2A) between the heat sink 10 and the unit lead frame 20A according to the embodiment. FIG. 3B is a cross-sectional view taken along the line BB in FIG. 3A.

[0044] 3A and 3B , in an embodiment, the heat sink 10 may be formed with two second groove portions 14 located adjacent to the first groove portion 13. The second groove portions 14 may be located, for example, so as to sandwich the first groove portion 13 between them.

[0045] In addition, the second groove portion 14 may be formed by pressing the periphery of the first groove portion 13 into a V-shape in cross section after the tip portion 22a of the protrusion portion 22 is accommodated in the first groove portion 13.

[0046] As a result, the side surfaces 22a1 of the tip portion 22a accommodated in the first groove portion 13 are pressed from both sides during the process of forming the second groove portion 14, so that the heat sink 10 is stably fixed to the unit lead frame 20A.

[0047] Therefore, according to the embodiment, when the semiconductor device 100 is manufactured, the heat sink 10 is unlikely to come off from the unit lead frame 20A, and the semiconductor device 100 can be manufactured stably.

[0048] Furthermore, in the embodiment, even if the width of the tip 22a of the protrusion 22 is smaller than the width of the first groove portion 13, after the tip 22a is accommodated in the first groove portion 13, the side surface 22a1 of the tip 22a can be pressed by the formation process of the second groove portion 14.

[0049] That is, in the embodiment, even if the width of the tip portion 22a of the protrusion portion 22 is smaller than the width of the first groove portion 13, the second groove portion 14 is formed in the heat sink 10, so that the tip portion 22a is formed so as to be able to fit into the first groove portion 13.

[0050] Therefore, according to the embodiment, the tip portion 22a can be easily accommodated in the first groove portion 13, which simplifies the manufacturing process of the lead frame 1.

[0051] In addition, in the embodiment, two second grooves 14 may be formed in the heat sink 10 for each first groove 13. This allows pressure to be applied to the side surface 22a1 of the tip portion 22a from two directions, so that the heat sink 10 is stably fixed to the unit lead frame 20A.

[0052] Therefore, according to the embodiment, when the semiconductor device 100 is manufactured, the heat sink 10 is unlikely to come off from the unit lead frame 20A, and the semiconductor device 100 can be manufactured stably.

[0053] <Semiconductor Device> Next, a semiconductor device 100 using the lead frame 1 according to the embodiment will be described with reference to Figures 4A and 4B. Figure 4A is a plan view showing an example of the semiconductor device 100 according to the embodiment. Figure 4B is a cross-sectional view taken along line CC shown in Figure 4A. For ease of understanding, the sealing resin 50 is shown by a dashed line in Figure 4A.

[0054] As shown in FIGS. 4A and 4B, the semiconductor device 100 according to the embodiment includes a part of a unit leadframe structure 1A, a semiconductor element 30, a plurality of bonding wires 40, and a sealing resin 50.

[0055] Examples of parts of the unit lead frame structure 1A included in the semiconductor device 100 include the heat sink 10, the plurality of leads 21, and parts of the plurality of protrusions 22.

[0056] The semiconductor element 30 is mounted on the mounting surface 11 of the heat sink 10. A plurality of bonding wires 40 electrically connect electrodes (not shown) located on the front surface of the semiconductor element 30 to the leads 21 corresponding to these electrodes. Note that the electrical connection between the electrodes and the leads 21 is not limited to the bonding wires 40, and various conductive members such as conductive clips may also be used.

[0057] The sealing resin 50 is made of, for example, epoxy resin and is formed into a predetermined shape by a molding process, etc. The sealing resin 50 seals the semiconductor element 30, the bonding wires 40, the mounting surface 11 of the heat sink 10, and the portions of the leads 21 on the semiconductor element 30 side.

[0058] The portions of the leads 21 opposite to the semiconductor element 30 side are exposed from the sealing resin 50 and function as external terminals (outer leads) of the semiconductor device 100. In addition, the rear surface 12 of the heat sink 10 is exposed from the sealing resin 50 and is bonded to a heat dissipation member or the like (not shown).

[0059] 4A shows a case where a part of the protrusion 22 does not protrude from the sealing resin 50, but in the present disclosure, a part of the protrusion 22 on the side opposite to the semiconductor element 30 side may be exposed so as to protrude from the sealing resin 50. This allows the exposed part of the protrusion 22 to be used as a ground terminal of the semiconductor device 100, etc.

[0060] In this case, it is preferable that the ground electrode (not shown) of the semiconductor element 30 and the heat sink 10 are connected by a bonding wire 40 or a conductive clip.

[0061] 3A and 3B , the second groove 14 is formed around the first groove 13, thereby improving the adhesion between the heat sink 10 and the protrusion 22. Therefore, according to the embodiment, when the exposed portion of the protrusion 22 is used as a ground terminal of the semiconductor device 100, the exposed portion of the protrusion 22 functions well as the terminal.

[0062] <Modification 1> Next, lead frames 1 according to various modifications of the embodiment will be described with reference to Fig. 5A to Fig. 8B. Fig. 5A is an enlarged cross-sectional view showing an example of a bonding region between a heat sink 10 and a unit lead frame 20A according to Modification 1 of the embodiment, and corresponds to Fig. 3B of the embodiment.

[0063] 5A, in the lead frame 1 of the first modification, the cross-sectional shape of the heat sink 10 that fits with the tip 22a of the protrusion 22 (see FIG. 4A) is different from that of the above-described embodiment. Specifically, in the first modification, the heat sink 10 has a covering portion 15 that covers at least a part of the upper surface 22a2 of the tip 22a.

[0064] The covering portion 15 may be formed, for example, by forming the second groove portion 14 by press working, and then pressing a portion closer to the first groove portion 13 than the second groove portion 14 into a flat shape.

[0065] In the first modification, the heat sink 10 has the covering portion 15, so that the tip portion 22a is supported from the upper surface 22a2 side as well, and therefore the heat sink 10 is stably fixed to the unit lead frame 20A.

[0066] Therefore, according to the first modification, the heat sink 10 is unlikely to come off the unit lead frame 20A when the semiconductor device 100 is manufactured, and therefore the semiconductor device 100 can be manufactured stably.

[0067] <Modifications 2 to 4> FIG. 5B is an enlarged plan view showing an example of a bonding region between the heat sink 10 and the unit lead frame 20A according to Modification 2 of the embodiment, and corresponds to FIG. 3A of the embodiment.

[0068] 5B , the lead frame 1 of the second modification example differs from the above-described embodiment in the arrangement of the second grooves 14. Specifically, in the second modification example, three second grooves 14 are formed around one first groove 13 in the heat sink 10.

[0069] Of these second groove portions 14, two second groove portions 14 are positioned, for example, to sandwich the first groove portion 13. Furthermore, the other second groove portion 14 is positioned to face one side that is not adjacent to the other of the three sides of the tip portion 22a that contacts the heat sink 10 in plan view.

[0070] In this way, three second grooves 14 are formed for each first groove 13 in the heat sink 10, so that the side surface 22a1 (see FIG. 3B ) of the tip 22a is pressed from three directions, thereby stably fixing the heat sink 10 to the unit lead frame 20A.

[0071] Therefore, according to the second modification, the heat sink 10 is less likely to come off the unit lead frame 20A when the semiconductor device 100 is manufactured, and therefore the semiconductor device 100 can be manufactured stably.

[0072] Furthermore, in variant example 2, even if the width of the tip 22a of the protrusion 22 is smaller than the width of the first groove 13, the heat sink 10 has three second grooves 14 formed therein, so that the tip 22a can fit into the first groove 13.

[0073] Therefore, according to the second modification, the tip portion 22a can be easily accommodated in the first groove portion 13, and the manufacturing process of the lead frame 1 becomes simple.

[0074] In the present disclosure, the number of second grooves 14 formed for each first groove 13 is not limited to two or three. For example, as shown in Fig. 6A , heat sink 10 may have one second groove 14 formed for each first groove 13. Fig. 6A is an enlarged plan view showing an example of a bonding region between heat sink 10 and unit lead frame 20A according to Modification 3 of the embodiment.

[0075] This also presses the side surface 22a1 (see FIG. 3B) of the tip portion 22a from one direction, so that the heat sink 10 is stably fixed to the unit lead frame 20A.

[0076] Therefore, according to the third modification, the heat sink 10 is less likely to come off the unit lead frame 20A when the semiconductor device 100 is manufactured, and the semiconductor device 100 can be manufactured stably.

[0077] Furthermore, in variant example 3, even if the width of the tip 22a of the protrusion 22 is smaller than the width of the first groove 13, one second groove 14 is formed in the heat sink 10, so that the tip 22a can fit into the first groove 13.

[0078] Therefore, according to the third modification, the tip portion 22a can be easily accommodated in the first groove portion 13, and therefore the manufacturing process of the lead frame 1 can be simplified.

[0079] 6B is an enlarged plan view showing another example of the bonding region between the heat sink 10 and the unit lead frame 20A according to Modification 3 of the embodiment. In the example of Fig. 6B, two first grooves 13 are located side by side on the same side of the heat sink 10, and two protrusions 22 are located at positions corresponding to the two first grooves 13, respectively.

[0080] 6B , the entire joint group formed by two first grooves 13 and two protrusions 22 may be pressed from both sides by a pair of second grooves 14. In this way, the entire joint group is pressed from both sides by the process of forming second grooves 14, so that heat sink 10 is stably fixed to unit lead frame 20A.

[0081] Therefore, according to the example of FIG. 6B, when the semiconductor device 100 is manufactured, the heat sink 10 is unlikely to come off the unit lead frame 20A, and the semiconductor device 100 can be manufactured stably.

[0082] 7A, the heat sink 10 does not necessarily have to have the second groove 14 (see FIG. 3A) formed in the vicinity of the first groove 13. FIG. 7A is an enlarged plan view showing an example of the bonding region between the heat sink 10 and the unit lead frame 20A according to the fourth modification of the embodiment.

[0083] This also allows the width of the tip 22 a of the protrusion 22 to be slightly larger than the width of the first groove 13 , so that the tip 22 a can be fitted into the first groove 13 .

[0084] Therefore, according to the fourth modification, the area required for bonding is smaller than when the heat sink 10 is fixed to the lead frame body 20 by caulking.

[0085] <Modifications 5 to 7> FIG. 7B is an enlarged plan view showing an example of a bonding region between the heat sink 10 and the unit lead frame 20A according to Modification 5 of the embodiment, and corresponds to FIG. 3A of the embodiment.

[0086] 7B , in the lead frame 1 of the fifth modification, the planar shapes of the first groove 13 and the tip 22 a of the protrusion 22 are different from those of the above-described embodiment. Specifically, in the fifth modification, the first groove 13 and the tip 22 a of the protrusion 22 are both formed to have a substantially T-shape in plan view.

[0087] As a result, the first groove portion 13 of the fifth modification includes a narrow groove portion 13a of width W1 located at the end 11a of the mounting surface 11, and a wide groove portion 13b of width W2 wider than the narrow groove portion 13a. Similarly, in the fifth modification, the tip portion 22a of the protrusion 22 includes a first portion 22a3 of width W1 located at the end 11a of the mounting surface 11, and a second portion 22a4 of width W2 wider than the first portion 22a3.

[0088] As described above, in the fifth modification, the first groove portion 13 includes the wide groove portion 13b, and the tip portion 22a of the protrusion 22 includes the second portion 22a4. Therefore, even if stress is applied to the heat sink 10 in a direction away from the protrusion 22, the heat sink 10 is unlikely to detach from the protrusion 22. Therefore, according to the fifth modification, the semiconductor device 100 can be manufactured stably.

[0089] In addition, in Modification 5, two second groove portions 14 located adjacent to narrow groove portion 13a may be formed in heat sink 10. For example, two second groove portions 14 may be located so as to sandwich narrow groove portion 13a and its vicinity therebetween.

[0090] As a result, the forming process of the second groove portion 14 presses the side surface 22a1 (see Figure 3B) of the tip portion 22a accommodated in the first groove portion 13 from both sides, thereby stably fixing the heat sink 10 to the unit lead frame 20A.

[0091] Therefore, according to the fifth modification, the heat sink 10 is less likely to come off the unit lead frame 20A when the semiconductor device 100 is manufactured, and the semiconductor device 100 can be manufactured stably.

[0092] 7B, the planar shapes of the first groove portion 13 and the tip portion 22a of the protrusion portion 22 are approximately T-shaped, but the present disclosure is not limited to such an example. Fig. 8A is an enlarged plan view showing an example of the bonding region between the heat sink 10 and the unit lead frame 20A according to the sixth modification of the embodiment.

[0093] As shown in FIG. 8A, in Modification 6, the wide groove portion 13b of the first groove portion 13 and the second portion 22a4 of the tip end 22a of the protrusion 22 are both substantially circular in plan view.

[0094] This also results in first groove 13 including wide groove 13b with width W2, and protrusion 22 including second portion 22a4 with width W2. Therefore, even if stress is applied to heat sink 10 in a direction away from protrusion 22, heat sink 10 is unlikely to detach from protrusion 22. Therefore, according to modification 6, semiconductor device 100 can be manufactured stably.

[0095] In addition, in Modification 6, two second grooves 14 located adjacent to the narrow groove 13a may be formed in the heat sink 10. As a result, the side surfaces 22a1 (see FIG. 3B ) of the tip portions 22a accommodated in the first grooves 13 are pressed from both sides by the process of forming the second grooves 14, so that the heat sink 10 is stably fixed to the unit lead frame 20A.

[0096] Therefore, according to the sixth modification, the heat sink 10 is less likely to come off the unit lead frame 20A when the semiconductor device 100 is manufactured, and the semiconductor device 100 can be manufactured stably.

[0097] 8B is an enlarged plan view showing an example of a bonding region between the heat sink 10 and the unit lead frame 20A according to Modification 7 of the embodiment. As shown in Fig. 8B, in Modification 7, the wide groove portion 13b of the first groove portion 13 and the second portion 22a4 of the tip portion 22a of the protrusion 22 are both approximately trapezoidal in plan view.

[0098] This also results in first groove 13 including wide groove 13b with width W2, and protrusion 22 including second portion 22a4 with width W2. Therefore, even if stress is applied to heat sink 10 in a direction away from protrusion 22, heat sink 10 is unlikely to detach from protrusion 22. Therefore, according to modification 7, semiconductor device 100 can be manufactured stably.

[0099] In addition, in Modification 7, two second grooves 14 located adjacent to the narrow groove 13a may be formed in the heat sink 10. As a result, the side surfaces 22a1 (see FIG. 3B ) of the tip portions 22a accommodated in the first grooves 13 are pressed from both sides by the process of forming the second grooves 14, so that the heat sink 10 is stably fixed to the unit lead frame 20A.

[0100] Therefore, according to the seventh modification, the heat sink 10 is unlikely to come off the unit lead frame 20A when the semiconductor device 100 is manufactured, and the semiconductor device 100 can be manufactured stably.

[0101] While the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments and various modifications are possible without departing from the spirit of the present disclosure. For example, in the above-described embodiments, an example in which two leads 21 are provided on one unit lead frame structure 1A is shown, but the present disclosure is not limited to such an example, and the number and arrangement of the leads 21 may be changed as appropriate depending on the specifications required for the semiconductor device 100.

[0102] Further advantages and modifications may readily occur to those skilled in the art. Therefore, the disclosure in its broader aspects is not limited to the specific details and representative embodiments shown and described above. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the claims of the present disclosure and their equivalents.

[0103] This application claims priority based on Japanese Patent Application No. 2024-59870 filed on April 3, 2024, and incorporates by reference all of the contents of said application.

[0104] REFERENCE SIGNS LIST 1 Lead frame 1A Unit lead frame structure 10 Heat sink 11 Mounting surface 11a End 13 First groove 13a Narrow groove 13b Wide groove 14 Second groove 20 Lead frame body 20A Unit lead frame 21 Lead 22 Protrusion 22a Tip 22a3 First portion 22a4 Second portion 30 Semiconductor element 40 Bonding wire 50 Sealing resin 100 Semiconductor device W1, W2 Width

Claims

1. A lead frame comprising: a heat sink having a mounting surface on which a semiconductor element is mounted; and a unit lead frame having leads, wherein a first groove is formed in the heat sink along the periphery of the mounting surface, and the unit lead frame has a protrusion at its tip whose shape corresponds to the first groove, and the protrusion fits into the first groove, thereby fixing the heat sink to the unit lead frame.

2. The lead frame according to claim 1, wherein the heat sink has a plurality of first grooves formed therein, the unit lead frame has a plurality of protrusions, and the heat sink is fixed to the unit lead frame by fitting the plurality of protrusions into the plurality of first grooves, respectively.

3. The lead frame according to claim 1 or 2, wherein a second groove portion is formed in the heat sink and positioned adjacent to the first groove portion.

4. The lead frame according to claim 3, wherein a plurality of second grooves are formed for each of the first grooves on the heat sink.

5. A lead frame according to any one of claims 1 to 4, wherein the first groove portion includes a narrow groove portion located at an end of the mounting surface, and a second portion that is wider than the narrow groove portion.

6. A semiconductor device comprising the lead frame according to any one of claims 1 to 5 and a semiconductor element mounted on the mounting surface.

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