Lead frame and lead frame manufacturing method

Abstract

This lead frame comprises a unit lead frame having a die pad and a lead. The unit lead frame has a recess on a surface thereof. The surface roughness on the inside of the recess is larger than the surface roughness of the periphery of the recess.

Description

Lead Frame and Method for Manufacturing the Same

[0001] The disclosed embodiments relate to a lead frame and a method for manufacturing the lead frame.

[0002] A semiconductor device includes, for example, a lead frame, a semiconductor chip mounted thereon, and a sealing resin for sealing the semiconductor chip. In the manufacturing process of such a semiconductor device, the lead frame and the semiconductor chip mounted thereon are covered with a thermosetting resin and heated to cure it.

[0003] Further, in order to improve the reliability of the semiconductor device, a technique for improving the adhesion between the lead frame and the sealing resin by performing a roughening process for increasing the surface roughness of the lead frame surface is known (see Patent Document 1).

[0004] Japanese Patent Application Laid-Open No. 3-295262

[0005] Further, in the manufacturing process of the lead frame, a technique for deforming a part of the lead frame in the thickness direction is used. However, in the above prior art, since the lead frame is deformed in the thickness direction, when a mold is pressed against the surface of the roughened lead frame, the surface roughness of the lead frame may be reduced by the mold. As a result, the adhesion between the lead frame and the sealing resin may be reduced.

[0006] One aspect of the embodiment has been made in view of the above, and an object thereof is to provide a lead frame and a method for manufacturing the lead frame capable of improving the adhesion between a unit lead frame and a sealing resin.

[0007] A lead frame according to one aspect of the embodiment includes a unit lead frame having a die pad and leads. Further, the unit lead frame has recesses on its surface. Further, the surface roughness of the inside of the recess is larger than the surface roughness of the periphery of the recess.

[0008] A method for manufacturing a lead frame according to one embodiment includes the steps of forming a pattern, forming recesses, roughening, and deforming. The pattern forming step involves forming a pattern of a unit lead frame having a die pad and leads on a metal plate. The recess forming step involves forming recesses on the surface of the unit lead frame. The roughening step involves roughening at least a portion of the surface of the unit lead frame, including the inside and surrounding areas of the recesses. The deforming step involves deforming the unit lead frame in the thickness direction while a mold is in close contact with the area around the recesses.

[0009] According to one embodiment, the adhesion between the unit lead frame and the sealing resin can be improved. The effects described herein are not necessarily limited, and any of the effects described in this disclosure may be present.

[0010] Figure 1A is an enlarged plan view showing an example of the configuration of a lead frame according to the embodiment. Figure 1B is a cross-sectional view showing an example of the configuration of a semiconductor device composed of the lead frame according to the embodiment. Figure 2A is a plan view showing an example of the configuration of a first lead according to the embodiment. Figure 2B is an enlarged cross-sectional view showing an example of the configuration of a recess according to the embodiment. Figure 3A is a plan view showing another example of the configuration of a first lead according to the embodiment. Figure 3B is an enlarged cross-sectional view showing another example of the configuration of a recess according to the embodiment. Figure 4 is an enlarged cross-sectional view showing another example of the configuration of a recess according to the embodiment. Figure 5A is an enlarged plan view showing an example of the configuration of a lead frame according to a modified example of the embodiment. Figure 5B is a cross-sectional view showing an example of the configuration of a semiconductor device composed of the lead frame according to a modified example of the embodiment. Figure 6A is a cross-sectional view taken along the line A-A shown in Figure 5A. Figure 6B is an enlarged plan view showing an example of the configuration of a support bar according to a modified example of the embodiment. Figure 7A is an enlarged plan view showing another example of the configuration of a support bar according to a modified example of the embodiment. Figure 7B is a flowchart showing an example of the manufacturing process steps for a lead frame according to the embodiment.

[0011] The lead frame and the method for manufacturing the lead frame disclosed herein will be described below with reference to the attached drawings. However, the embodiments described below do not limit this disclosure.

[0012] Furthermore, it should be noted that drawings are schematic representations, and the dimensional relationships and proportions of each element may differ from reality. Moreover, there may be discrepancies in dimensional relationships and proportions between drawings themselves.

[0013] <Embodiment> First, the lead frame 1 according to the embodiment and the semiconductor device 100 manufactured using this lead frame 1 will be described with reference to Figures 1A to 4. Figure 1A is an enlarged plan view showing an example of the configuration of the lead frame 1 according to the embodiment. Figure 1B is a cross-sectional view showing an example of the configuration of the semiconductor device 100 constructed by the lead frame 1 according to the embodiment.

[0014] The lead frame 1 shown in Figure 1A is applicable to a semiconductor device 100 that mounts power semiconductor elements such as power MOSFETs (Metal Oxide Semiconductor Field Effect Transistors) and IGBTs (Insulated Gate Bipolar Transistors).

[0015] The lead frame 1 according to this embodiment has, for example, a strip shape in plan view, and a plurality of unit lead frames 10 are formed side by side along the longitudinal direction. Each of these unit lead frames 10 corresponds to a part of the semiconductor device 100 manufactured using the lead frame 1. In this embodiment, the plurality of unit lead frames 10 may be formed side by side not only along the longitudinal direction of the lead frame 1 but also along the short direction.

[0016] As shown in Figure 1A, a unit lead frame 10 has a die pad 11 and multiple leads 12 (two in Figure 1A). Connecting bars 13 are located between adjacent unit lead frames 10.

[0017] The die pad 11 is provided, for example, extending from the center of the unit lead frame 10 to one side (the left side in Figure 1A). The die pad 11 has a tip portion 11a and a base portion 11b. At the base portion 11b, the die pad 11 is connected to and supported by the connecting bar 13.

[0018] As shown in Figure 1B, a semiconductor element 101 can be mounted on the tip portion 11a of the die pad 11. The base portion 11b of the die pad 11 functions as an external terminal (outer lead) of the semiconductor device 100 and is soldered to a substrate or the like (not shown).

[0019] Multiple leads 12 are arranged side by side on the other side (right side in Figure 1A) of a unit lead frame 10, with each lead 12a extending from the other end of the unit lead frame 10 toward the lead 11a of the die pad 11. As shown in Figure 1B, these leads 12 function as connection terminals for the semiconductor device 100.

[0020] The lead 12 has a tip portion 12a, a base portion 12b, and a deformable portion 12c. As shown in Figure 1B, in the semiconductor device 100, a bonding wire 102 made of Cu, Cu alloy, Au, Au alloy, etc. is connected to the tip portion 12a of the lead 12.

[0021] The semiconductor device 100 includes a unit lead frame 10, semiconductor elements 101, and bonding wires 102, as well as a sealing resin 103. The sealing resin 103 is made of, for example, epoxy resin and is molded into a predetermined shape by a molding process or the like.

[0022] In this embodiment, the sealing resin 103 seals, for example, the semiconductor element 101, the bonding wire 102, the front side of the tip portion 11a of the die pad 11, the tip portion 12a and the deformed portion 12c of the lead 12, and so on.

[0023] Furthermore, the base end 12b of the lead 12 functions as an external terminal (outer lead) of the semiconductor device 100 and is soldered to a substrate or the like (not shown). In addition, in semiconductor devices 100 in which the back surface of the die pad 11 is exposed from the sealing resin 103 or in which a heat slag is provided, the back surfaces of these are soldered to a substrate or the like.

[0024] Furthermore, as shown in Figure 1B, the deformed portion 12c of the lead 12 is located between the tip portion 12a and the base portion 12b, and is a part that deforms in the thickness direction of the unit lead frame 10. This deformed portion 12c can be formed, for example, by step processing using a mold.

[0025] As shown in Figure 1A, the multiple leads 12 include a first lead 12A and a second lead 12B. The first lead 12A is, for example, a lead 12 that is wider than the second lead 12B.

[0026] In the semiconductor device 100, the first lead 12A is electrically connected to, for example, a source electrode (not shown) located on the front surface of the semiconductor element 101 by a plurality of bonding wires 102.

[0027] In addition, in the semiconductor device 100, the second lead 12B is electrically connected, for example, to a gate electrode (not shown) located on the front surface of the semiconductor element 101 by a bonding wire 102. Furthermore, in the semiconductor device 100, the die pad 11 is electrically connected, for example, to a drain electrode (not shown) located on the back surface of the semiconductor element 101.

[0028] In the semiconductor device 100, for example, the base end 12b of the first lead 12A functions as the source terminal, the base end 12b of the second lead 12B functions as the gate terminal, and the base end 11b of the die pad 11 functions as the drain terminal.

[0029] As shown in Figure 1A and other figures, the lead frame 1 according to this embodiment comprises a base material 2 and a plating layer 3. The base material 2 is made of a conductive material (for example, a metallic material such as copper or a copper alloy). The plating layer 3 is formed on the surface of the base material 2 and is mainly composed of, for example, Ag (silver) or Ni (nickel).

[0030] Furthermore, at least one undercoat plating layer, mainly composed of Cu, Ni, Pd, Au, Ag, etc., may be formed between the substrate 2 and the plating layer 3 for the purpose of preventing metal diffusion and improving heat resistance. Alternatively, a plating layer mainly composed of Au, Pt, Pd, Ag, etc., may be formed on the surface of the plating layer 3.

[0031] Furthermore, in the lead frame 1 according to this embodiment, the plating layer 3 is formed on the tip portion 11a of the die pad 11 and on the tip portions 12a of the multiple leads 12, respectively. This facilitates the joining of the die pad 11 to the semiconductor element 101 and the joining of the leads 12 to the bonding wire 102.

[0032] Figure 2A is a plan view showing an example of the configuration of the first lead 12A according to the embodiment. As shown in Figure 2A, the unit lead frame 10 according to the embodiment has one or more (multiple in Figure 2A) recesses 14 on its surface, for example, on the surface of the tip portion 12a of the first lead 12A.

[0033] This recess 14 is located, for example, at the tip portion 12a where the plating layer 3 is provided. The recess 14 is, for example, rectangular in plan view. Also, as shown in Figure 2B, the size of the bottom of the recess 14 is larger than the size of the opening of the recess 14. Figure 2B is an enlarged cross-sectional view showing an example of the configuration of the recess 14 according to the embodiment.

[0034] In this embodiment, the surface roughness of the interior 14a of the recess 14 may be greater than the surface roughness of the surrounding 15 of the recess 14. By making the surface roughness of the interior 14a of the recess 14 greater than the surface roughness of the surrounding 15 of the recess 14, the adhesion between the unit lead frame 10 and the sealing resin 103 (see Figure 1B) can be improved. The reason for this is explained below.

[0035] The first reason is that the mechanical adhesion between the unit lead frame 10 and the sealing resin 103 is improved by the so-called anchoring effect that occurs when the sealing resin 103 enters the recess 14.

[0036] A second reason is that, because a rough surface, for example, a plated layer 3 with a roughened surface, is located inside the recess 14a, the sealing resin 103 penetrates into the irregularities of the roughened plated layer 3 inside the recess 14a, further improving the mechanical adhesion between the unit lead frame 10 and the sealing resin 103.

[0037] Furthermore, in this embodiment, the reliability of the semiconductor device 100 (see Figure 1B) is improved by improving the adhesion between the unit lead frame 10 and the sealing resin 103. Therefore, according to this embodiment, the adhesion between the unit lead frame 10, on which the deformed portion 12c is provided, and the sealing resin 103 can be improved.

[0038] Furthermore, in this embodiment, as shown in Figure 2A, the recesses 14 may be located near one or more (multiple in Figure 2A) dots 16 in the plating layer 3 where the bonding wire 102 (see Figure 1B) is joined.

[0039] This improves the adhesion between the unit lead frame 10 and the sealing resin 103 in the vicinity of the dotting point 16, thereby suppressing the breakage of the nearby bonding wire 102 due to the sealing resin 103 peeling off. Therefore, according to this embodiment, the reliability of the semiconductor device 100 is further improved.

[0040] Furthermore, in this embodiment, the multiple recesses 14 may be arranged in a matrix. This allows the recesses 14 to be placed over a wide area without making the total area of ​​the recesses 14 excessively large. Therefore, according to this embodiment, it is possible to improve the adhesion over a wide area while suppressing the internal stress that occurs when forming the recesses 14.

[0041] Note that, in the embodiment, the arrangement of the recess 14 is not limited to the example of FIG. 2A. FIG. 3A is a plan view showing another example of the configuration of the first lead 12A according to the embodiment. As shown in FIG. 3A, in the present disclosure, a recess 14 extending in a groove shape may be arranged in the first lead 12A.

[0042] Also, this also improves the adhesion between the unit lead frame 10 and the sealing resin 103, so that the reliability of the semiconductor device 100 is improved.

[0043] Further, in the embodiment, as shown in FIG. 2B, the size of the bottom of the recess 14 may be larger than the size of the opening of the recess 14. Thereby, the anchor effect between the unit lead frame 10 and the sealing resin 103 is further enhanced, so that the adhesion between the unit lead frame 10 and the sealing resin 103 can be further improved.

[0044] Note that, in the present disclosure, the cross-sectional shape of the recess 14 is not limited to the example of FIG. 2B. FIGS. 3B and 4 are enlarged cross-sectional views showing another example of the configuration of the recess 14 according to the embodiment. As shown in FIG. 3B, the recess 14 may be substantially U-shaped in cross-section. Also, as shown in FIG. 4, the recess 14 may be substantially V-shaped in cross-section.

[0045] Also, this also improves the adhesion between the unit lead frame 10 and the sealing resin 103, so that the reliability of the semiconductor device 100 is improved.

[0046] Further, in the embodiment, the surface roughness of the periphery 15 of the recess 14 may be larger than the surface roughness of a portion away from the recess 14, for example, a portion where the substrate 2 is exposed without the plating layer 3.

[0047] Thereby, the mechanical adhesion between the unit lead frame 10 and the sealing resin 103 can be improved at the periphery 15 of the recess 14, so that the adhesion between the unit lead frame 10 and the sealing resin 103 can be improved.

[0048] Note that, in the embodiment, the bonding wire 102 is connected to the tip portion 12a of the lead 12, but the semiconductor element 101 and the tip portion 12a of the lead 12 may be connected by a metal part such as a metal clip. <

[0049] <Modification> Next, a modified lead frame 1 according to the embodiment and a semiconductor device 100 manufactured using this lead frame 1 will be described with reference to Figures 5A to 7A. Figure 5A is an enlarged plan view showing an example of the configuration of the modified lead frame 1 according to the embodiment. Figure 5B is a cross-sectional view showing an example of the configuration of the semiconductor device 100 constructed by the modified lead frame 1 according to the embodiment.

[0050] The lead frame 1 shown in Figure 5A is a lead frame used in the manufacture of a QFP (Quad Flat Package) type semiconductor device 100. The technology of this disclosure may also be applied to lead frames used in the manufacture of other types of semiconductor devices, such as SOP (Small Outline Package) devices.

[0051] The modified lead frame 1, for example, has a strip shape in plan view, and multiple unit lead frames 10 are formed in a row along the longitudinal direction. In the modified example, multiple unit lead frames 10 may be formed not only along the longitudinal direction of the lead frame 1, but also along the short direction.

[0052] As shown in Figure 5A, the modified unit lead frame 10 has a die pad 11, a plurality of leads 12, a plurality of support bars 17, and a dam bar 18. Although not shown in Figure 5A, pilot holes may be arranged in a row on the long side of the lead frame 1.

[0053] The modified die pad 11 is provided, for example, in the central part of a unit lead frame 10. A semiconductor element 101 can be mounted on the front side of this die pad 11, as shown in Figure 5B.

[0054] In the modified die pad 11, the die pad 11 is connected to the outer edge of the unit lead frame 10 by a plurality of support bars 17 and is supported by the outer edge of the unit lead frame 10. These plurality of support bars 17 are, for example, connected to the four corners of the rectangular die pad 11.

[0055] In this modified example, multiple leads 12 are arranged in a line around the die pad 11, with each lead tip 12a extending from the outer edge of the unit lead frame 10 toward the die pad 11. As shown in Figure 5B, these leads 12 function as connection terminals for the semiconductor device 100.

[0056] The modified lead 12 has a tip portion 12a and a base portion 12b. As shown in Figure 5B, in the semiconductor device 100, a bonding wire 102 made of Cu, Cu alloy, Au, Au alloy, etc., is connected to the tip portion 12a of the lead 12. Therefore, the lead frame 1 is required to have high bonding characteristics with the bonding wire 102. The dam bar 18 connects adjacent leads 12 to each other.

[0057] The modified semiconductor device 100 includes a lead frame 1, a semiconductor element 101, and bonding wires 102, in addition to a sealing resin 103. In the modified device, the sealing resin 103 seals, for example, the semiconductor element 101, the bonding wires 102, the surface of the die pad 11, and the tip portion 12a of the lead 12.

[0058] Furthermore, the base end 12b of the lead 12 functions as an external terminal (outer lead) of the semiconductor device 100 and is soldered to a substrate or the like. In addition, in semiconductor devices 100 in which the back surface of the die pad 11 is exposed from the sealing resin 103 or in which a heat slag is provided, the back surfaces of these are soldered to a substrate or the like.

[0059] The dam bar 18 has the function of a dam to prevent the resin being used from leaking out to the base end 12b side during the molding process for forming the sealing resin 103, and is ultimately cut off during the manufacturing process of the semiconductor device 100.

[0060] Furthermore, in the modified lead frame 1, a plating layer 3 is formed on the tip portion 12a of the die pad 11 and the lead 12. This plating layer 3 is composed mainly of, for example, Ag or Ni.

[0061] This makes it easier to join the lead frame 1 and the bonding wire 102.

[0062] Figure 6A is a cross-sectional view taken along the line A-A shown in Figure 5A, and shows the cross-sectional structure of the die pad 11 and support bar 17 of the lead frame 1.

[0063] As shown in Figure 6A, the modified lead frame 1 comprises a base material 2 and a plating layer 3. The base material 2 is made of a conductive material (for example, a metallic material such as copper or a copper alloy). The plating layer 3 is formed on the front surface of the base material 2 and is a plating layer mainly composed of, for example, Ag.

[0064] In the modified example, a rough surface is formed on at least a portion of the substrate 2. The rough surface may be a roughened plating layer, a roughened surface of the substrate 2, or needle-shaped oxides (not shown).

[0065] As shown in Figure 6A, the support bar 17 has a base end 21, a flat portion 22, and a deformable portion 23. The base end 21 is connected to the outer edge of the unit lead frame 10, as shown in Figure 1A. The flat portion 22 is located between the base end 21 and the deformable portion 23 and is a flat portion having approximately the same height as the lead 12 (see Figure 1A).

[0066] The deformed portion 23 is located, for example, at or near the tip of the support bar 17 and deforms in the thickness direction relative to the lead 12 (i.e., relative to the flat portion 22) toward the back side of the base material 2.

[0067] As a result, as shown in Figure 5B, the die pad 11 protrudes from the lead 12 towards the back side of the base material 2. This deformed portion 23 can be formed, for example, by bending using a mold.

[0068] Figure 6B is an enlarged plan view showing an example of the configuration of the support bar 17 according to a modified embodiment. In the modified embodiment, as shown in Figure 6B, one or more (multiple in Figure 6B) recesses 14 are located in the flat portion 22 located near the deformed portion 23.

[0069] In this modified example, similar to the embodiment described above, the surface roughness of the interior 14a of the recess 14 (see Figure 2B) may be greater than the surface roughness of the surrounding area 15 (see Figure 2B) of the recess 14. This improves the mechanical adhesion between the unit lead frame 10 and the sealing resin 103, similar to the embodiment described above. Furthermore, if the rough surface is a needle-shaped oxide, chemical adhesion will also be improved in addition to mechanical adhesion.

[0070] Therefore, according to the modified example, the adhesion between the unit lead frame 10 and the sealing resin 103 can be improved.

[0071] In another modified example, the recess 14 may be located near the deformed portion 23 of the support bar 17. If the recess 14 is not located near the deformed portion 23, when forming the deformed portion 23 of the support bar 17, the entire mold comes into close contact with the needle-shaped oxide located near the deformed portion 23, resulting in a reduced surface roughness of the needle-shaped oxide to which the entire mold comes into contact.

[0072] On the other hand, in the modified example, the recess 14 is located near the deformed portion 23 of the support bar 17. Therefore, even if the mold is in close contact with the surrounding area 15 (see Figure 2B) of the recess 14 when forming the deformed portion 23 of the support bar 17, the surface roughness of the inside 14a (see Figure 2B) of the recess 14 can be maintained at a high level.

[0073] Therefore, according to the modified example, the adhesion between the unit lead frame 10, on which the deformed portion 23 is provided, and the sealing resin 103 can be improved.

[0074] Furthermore, in the modified version, the multiple recesses 14 may be arranged in a matrix. This allows the recesses 14 to be placed over a wide area without excessively increasing the total area of ​​the recesses 14. Therefore, according to the modified version, it is possible to improve the adhesion over a wide area while suppressing the internal stress that occurs when forming the recesses 14.

[0075] In the modified example, the arrangement of the recess 14 is not limited to the example in Figure 6B. Figure 7A is an enlarged plan view showing another example of the configuration of the support bar 17 according to a modified example of the embodiment. As shown in Figure 7A, in this disclosure, the recess 14 may be located not only in the vicinity of the deformed portion 23, but also on the deformed portion 23 itself.

[0076] This also improves the adhesion between the unit lead frame 10 and the sealing resin 103, thereby improving the reliability of the semiconductor device 100.

[0077] <Manufacturing Process> Next, the manufacturing process of the lead frame 1 according to the embodiment will be explained with reference to Figure 7B. Figure 7B is a flowchart showing an example of the steps in the manufacturing process of the lead frame 1 according to the embodiment.

[0078] As shown in Figure 7B, first, a pattern forming step is performed in which a pattern of a unit lead frame 10, which includes a die pad 11 and a plurality of leads 12, is formed on a metal plate (step S1). The pattern of such a unit lead frame 10 is, for example, the pattern shown in Figure 1A in plan view.

[0079] This pattern formation process may be carried out, for example, by stamping a metal plate or by etching a metal plate.

[0080] Next, a recess formation step is performed to form one or more recesses 14 on the surface of the metal plate on which the pattern of the unit lead frame 10 is formed (step S2). This recess formation step may be performed, for example, by stamping the metal plate or by etching the metal plate.

[0081] Note that the etching process in step S1 and the etching process in step S2 may be performed simultaneously.

[0082] Next, a roughening process is performed on the metal plate in which one or more recesses 14 are formed, in which at least a portion of the surface is roughened (step S3). This roughening process is carried out, for example, by electroplating the metal plate in which the recesses 14 are formed in a plating bath containing metal ions and roughening additives, thereby forming a roughened plating layer 3 on the surface of the metal plate.

[0083] Furthermore, this roughening process may be carried out, for example, by immersing the metal plate in a micro-etching solution to form a roughened metal plate surface.

[0084] Furthermore, this roughening process may be carried out, for example, by immersing the metal plate on which the recess 14 is formed in a strongly oxidizing alkaline solution, connecting the anode side of a rectifier to the metal plate, and connecting the cathode side to an electrode plate placed in the solution tank, thereby performing anodic oxidation of the metal plate.

[0085] Next, a deformation process is performed on the metal plate, whose surface has been roughened to at least a portion thereof, to deform a predetermined portion in the thickness direction (step S4). This deformation process is carried out, for example, by step processing or bending using a mold. This completes the manufacturing process of the lead frame 1 according to the embodiment.

[0086] While embodiments of this disclosure have been described above, this disclosure is not limited to the embodiments described above, and various modifications are possible without departing from its spirit.

[0087] For example, the above embodiment shows an example in which the recess 14 is located on the front surface of the unit lead frame 10, but the present disclosure is not limited to such an example. For example, in the present disclosure, the recess 14 may be located on the back surface of the unit lead frame 10, or the recess 14 may be located on both sides of the unit lead frame 10.

[0088] As described above, the lead frame 1 according to the embodiment comprises a unit lead frame 10 having a die pad 11 and leads 12. The unit lead frame 10 also has a recess 14 on its surface. Furthermore, the surface roughness of the inside 14a of the recess 14 is greater than the surface roughness of the surrounding 15 of the recess 14. This improves the adhesion between the unit lead frame 10 and the sealing resin 103.

[0089] Furthermore, in the lead frame 1 according to the embodiment, the unit lead frame 10 has a deformed portion 12c (deformed portion 23) that is deformed in the thickness direction, and the recess 14 is located in at least one of the deformed portion 12c (deformed portion 23) and in the vicinity of the deformed portion 12c (deformed portion 23). This makes it possible to improve the adhesion between the unit lead frame 10 on which the deformed portion 12c or deformed portion 23 is provided and the sealing resin 103.

[0090] Furthermore, in the lead frame 1 according to this embodiment, the unit lead frame 10 has a plating layer 3 and a dotting portion 16 in the plating layer 3 to which the bonding wire 102 is joined, and the recess 14 is located near the dotting portion 16. This further improves the reliability of the semiconductor device 100.

[0091] Furthermore, in the lead frame 1 according to this embodiment, the unit lead frame 10 has a plurality of recesses 14 on its surface, and the plurality of recesses 14 are arranged in a matrix. This makes it possible to improve adhesion over a wide area while suppressing the internal stress that occurs when forming the recesses 14.

[0092] Furthermore, in the lead frame 1 according to this embodiment, the size of the bottom of the recess 14 is larger than the size of the opening of the recess 14. This further improves the adhesion between the unit lead frame 10 and the sealing resin 103.

[0093] Furthermore, in the lead frame 1 according to this embodiment, the surface roughness of the area 15 surrounding the recess 14 is greater than the surface roughness of the area away from the recess 14. This improves the adhesion between the unit lead frame 10 and the sealing resin 103.

[0094] Furthermore, the manufacturing method of the lead frame 1 according to the embodiment includes a step of forming a pattern (step S1), a step of forming a recess 14 (step S2), a roughening step (step S3), and a deformation step (step S4). In the step of forming a pattern (step S1), a pattern of a unit lead frame 10 having a die pad 11 and leads 12 is formed on a metal plate. In the step of forming a recess 14, a recess 14 is formed on the surface of the unit lead frame 10. In the roughening step (step S3), at least a portion of the surface of the unit lead frame 10, including the inside 14a and the surrounding area 15 of the recess 14, is roughened. In the deformation step (step S4), the unit lead frame 10 is deformed in the thickness direction while a mold is brought into close contact with the surrounding area 15 of the recess 14. This improves the adhesion between the unit lead frame 10 and the sealing resin 103.

[0095] Further effects and modifications can be readily derived by those skilled in the art. Therefore, broader aspects of this disclosure are not limited to the specific details and representative embodiments expressed and described above. Accordingly, various modifications are possible without departing from the spirit or scope of the overall concept of the invention as defined by the appended claims and their equivalents.

[0096] Furthermore, this technology can also take the following configurations: (1) A lead frame comprising a unit lead frame having a die pad and leads, wherein the unit lead frame has a recess on its surface, and the surface roughness inside the recess is greater than the surface roughness around the recess. (2) The lead frame according to (1) wherein the unit lead frame has a deformed portion that is deformed in the thickness direction, and the recess is located in at least one of the deformed portion and the vicinity of the deformed portion. (3) The lead frame according to (1) or (2) wherein the unit lead frame has a plating layer and a dotting portion in the plating layer where a bonding wire is joined, and the recess is located in the vicinity of the dotting portion. (4) The lead frame according to any one of (1) to (3) wherein the unit lead frame has a plurality of recesses on its surface, and the plurality of recesses are arranged in a matrix. (5) The lead frame according to any one of (1) to (4) wherein the size of the bottom of the recess is greater than the size of the opening of the recess. (6) A lead frame according to any one of (1) to (5) above, wherein the surface roughness around the recess is greater than the surface roughness of the portion away from the recess. (7) A method for manufacturing a lead frame, comprising: forming a pattern of a unit lead frame having a die pad and leads on a metal plate; forming a recess on the surface of the unit lead frame; roughening at least a portion of the surface of the unit lead frame, including the inside and around the recess; and deforming the unit lead frame in the thickness direction while a mold is in close contact with the periphery of the recess.

[0097] This application is based on Japanese Patent Application No. 2024-174828, filed on 4 October 2024, the contents of which are incorporated herein by reference.

Claims

1. A lead frame comprising a die pad and a unit lead frame having leads, wherein the unit lead frame has a recess on its surface, and the surface roughness inside the recess is greater than the surface roughness around the recess.

2. The lead frame according to claim 1, wherein the unit lead frame has a deformed portion that is deformed in the thickness direction, and the recess is located in at least one of the deformed portion and the vicinity of the deformed portion.

3. The lead frame according to claim 1 or 2, wherein the unit lead frame has a plating layer and a dotting portion in the plating layer where a bonding wire is joined, and the recess is located near the dotting portion.

4. The lead frame according to claim 1 or 2, wherein the unit lead frame has a plurality of recesses on its surface, and the plurality of recesses are arranged in a matrix.

5. The lead frame according to claim 1 or 2, wherein the size of the bottom of the recess is larger than the size of the opening of the recess.

6. The lead frame according to claim 1 or 2, wherein the surface roughness around the recess is greater than the surface roughness of the portion away from the recess.

7. A method for manufacturing a lead frame, comprising the steps of: forming a pattern of a unit lead frame having a die pad and leads on a metal plate; forming a recess on the surface of the unit lead frame; roughening at least a portion of the surface of the unit lead frame, including the inside and surroundings of the recess; and deforming the unit lead frame in the thickness direction while a mold is in close contact with the surroundings of the recess.

Images