Lead frame and method for manufacturing the same

Abstract

The present invention provides a lead frame and a manufacturing method thereof. The lead frame involved in the present invention comprises: a pin portion having a side surface and another side surface; a connecting bar having a side surface and another side surface, the pin portion being connected to the connecting bar; and a protrusion portion, which is arranged on one side surface of the connecting bar, wherein one side surface of the connecting bar is located between one side surface and the other side surface of the pin portion, and the front end of the protrusion portion is located between one side surface of the pin portion and one side surface of the connecting bar. The lead frame involved in the present invention can prevent the cutting blade from being blocked during cutting processing.

Description

Technical Field

[0001] The invention relates to a lead frame and a manufacturing method thereof. Background Art

[0002] As a thin semiconductor device, a QFN (Quad Flat Non-leaded package) type semiconductor device is known. In a QFN type semiconductor device, a semiconductor element placed on a placement surface of a lead frame is encapsulated with an encapsulation resin, and a portion of a lead portion is exposed from a back surface located on the opposite side of the placement surface.

[0003] In the manufacturing process of the QFN type semiconductor device, first, a lead frame is obtained by etching a metal plate, in which regions corresponding to the semiconductor elements are arranged in a matrix. In the lead frame, regions corresponding to the semiconductor elements are divided by connecting bars. A plurality of pins arranged around the semiconductor elements are connected to the connecting bars. Next, in the manufacturing process of the QFN type semiconductor device, molding is performed to encapsulate the semiconductor elements with an encapsulation resin.

[0004] Later, in the manufacturing process of the QFN type semiconductor device, a cutting process is performed to separate the semiconductor elements by cutting the encapsulating resin and the connecting strip with a cutting blade. During the cutting process, metal burrs may be generated on the cut surface of the pin portion cut from the connecting strip. Metal burrs may cause short circuits between adjacent pin portions, which is not ideal. Therefore, the following method is adopted: by providing a recessed portion formed by half etching on the connecting strip, the generation of metal burrs from the connecting strip is suppressed. However, when the recessed portion formed by half etching is provided on the connecting strip, the rigidity of the connecting strip is reduced. Therefore, the connecting strip may be deformed.

[0005] In view of this, a technique has been proposed in which a portion that is not subjected to the half-etching process is left on the back surface that is located on the opposite side to the surface on which the connection bar is placed.

[0006] Patent Document 1: Japanese Patent Application Publication No. 2015-72946 Summary of the invention

[0007] In addition, in the manufacturing process of QFN type semiconductor devices, after plastic encapsulation, an external plating process is sometimes performed, that is, an external plating layer such as a solder plating film is formed on the portion exposed from the encapsulation resin on the back side of the lead frame. For example, the external terminal portion of the lead portion is a portion exposed from the encapsulation resin, and a solder plating film is formed on the external terminal portion of the lead portion by performing the external plating process.

[0008] As in the above-mentioned technology, when there is a portion on the back of the connecting strip that has not been half-etched, the portion that has not been half-etched is located on the same surface as the external terminal portion of the lead portion, so that it is exposed from the encapsulation resin on the back of the lead frame. Therefore, if the outer plating process is performed, a solder plating film is also formed on the portion on the back of the connecting strip that has not been half-etched. Therefore, when the cutting process is performed, the cutting blade cuts the solder plating film together with the connecting strip. As a result, there is a possibility that the solder plating film adheres to the blade edge of the cutting blade and is blocked.

[0009] The technology disclosed in the present application has been made in view of the above-mentioned problems, and an object thereof is to provide a lead frame and a method for manufacturing the same, which can realize a lead frame capable of preventing a dicing blade from being clogged during dicing.

[0010] The lead frame disclosed in the present application, as one embodiment, includes: a pin portion, which has a one side surface and another side surface; a connecting bar, which has a one side surface and another side surface, and the above-mentioned pin portion is connected to the connecting bar; and a protrusion portion, which is arranged on one side surface of the above-mentioned connecting bar, wherein the one side surface of the above-mentioned connecting bar is located between the one side surface and the other side surface of the above-mentioned pin portion, and the front end of the above-mentioned protrusion portion is located between the one side surface of the above-mentioned pin portion and the one side surface of the above-mentioned connecting bar.

[0011] According to one embodiment of the lead frame disclosed in the present application, there is achieved an effect of realizing a lead frame capable of preventing a dicing blade from being clogged during dicing. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a plan view showing the surface of the lead frame according to Example 1.

[0013] Figure 2 It is a plan view showing the back side of the lead frame according to the first embodiment.

[0014] Figure 3 For along Figure 1 Cross-sectional view along line III-III.

[0015] Figure 4A This is a partially enlarged plan view showing an enlarged view of the back side of the connecting strip according to the first embodiment.

[0016] Figure 4B This is a cross-sectional view of the long lead connecting portion of the connection bar involved in Example 1.

[0017] Figure 4C 4 is a cross-sectional view of the short pin connection portion of the connection bar involved in Example 1.

[0018] Figure 5This is a plan view showing the surface of a semiconductor device manufactured using the lead frame according to Example 1.

[0019] Figure 6 For along Figure 5 Cross-sectional view along line VI-VI.

[0020] Fig. 7A It is a cross-sectional view showing the method for manufacturing the lead frame according to the first embodiment.

[0021] Figure 7B It is a cross-sectional view showing the method for manufacturing the lead frame according to the first embodiment.

[0022] Figure 7C It is a cross-sectional view showing the method for manufacturing the lead frame according to the first embodiment.

[0023] Fig.7D It is a cross-sectional view showing the method for manufacturing the lead frame according to the first embodiment.

[0024] Fig. 7E It is a cross-sectional view showing the method for manufacturing the lead frame according to the first embodiment.

[0025] Figure 7F It is a cross-sectional view showing the method for manufacturing the lead frame according to the first embodiment.

[0026] Figure 7G It is a cross-sectional view showing the method for manufacturing the lead frame according to the first embodiment.

[0027] Figure 7H It is a cross-sectional view showing the method for manufacturing the lead frame according to the first embodiment.

[0028] Fig. 8A It is a cross-sectional view showing the method for manufacturing the semiconductor device according to the first embodiment.

[0029] Figure 8B It is a cross-sectional view showing the method for manufacturing the semiconductor device according to the first embodiment.

[0030] Figure 8C It is a cross-sectional view showing the method for manufacturing the semiconductor device according to the first embodiment.

[0031] Fig.8D It is a cross-sectional view showing the method for manufacturing the semiconductor device according to the first embodiment.

[0032] Fig. 8E It is a cross-sectional view showing the method for manufacturing the semiconductor device according to the first embodiment.

[0033] Fig.8F It is a cross-sectional view showing the method for manufacturing the semiconductor device according to the first embodiment.

[0034] Figure 8G It is a cross-sectional view showing the method for manufacturing the semiconductor device according to the first embodiment.

[0035] Figure 8H It is a cross-sectional view showing the method for manufacturing the semiconductor device according to the first embodiment.

[0036] Fig.9A This is a partially enlarged plan view showing an enlarged view of the back side of the connecting strip involved in Example 2.

[0037] Fig. 9B This is a cross-sectional view of the long lead connecting portion of the connection bar involved in Example 2.

[0038] Fig. 9C This is a cross-sectional view of the short pin connection portion of the connection bar involved in Example 2.

[0039] Fig.10 It is a plan view showing the surface of the lead frame according to the third embodiment.

[0040] Fig.11 It is a plan view showing the back side of the lead frame according to the third embodiment.

[0041] Fig.12 This is a partially enlarged plan view showing an enlarged view of the back side of the connecting strip involved in Example 3.

[0042] Fig.13 This is a partially enlarged plan view showing an enlarged view of the back side of the connecting strip involved in Example 4.

[0043] Fig.14 This is a partially enlarged plan view showing an enlarged view of the back side of the connecting strip involved in Example 5.

[0044] Fig.15 It is a plan view showing the surface of the lead frame involved in Example 6.

[0045] Fig.16 For along Fig.15 Cross-sectional view along line XVI-XVI.

[0046] Fig.17 A side cross-sectional view showing an example of the structure of a semiconductor device manufactured using the lead frame according to the sixth embodiment.

[0047] Explanation of symbols

[0048] 10, 10A~10E lead frame; 14 lead frame unit; 15 chip pad; 16A long pin portion; 16B short pin portion; 17 connecting bar; 17a surface; 17b back side; 18A long pin connecting portion; 18B short pin connecting portion; 20, 20E semiconductor device; 21 semiconductor element; 22 bonding wire; 24 encapsulating resin; 26 solder plating; 53 protrusion. DETAILED DESCRIPTION

[0049] Hereinafter, with reference to the accompanying drawings, an embodiment of the lead frame and the method for manufacturing the lead frame disclosed in the present application will be described in detail. In addition, the technology disclosed in the present invention is not limited to the embodiment. In addition, in the embodiment, the same symbols are given to the structural elements having the same functions, and their repeated descriptions are omitted.

[0050] Example 1

[0051] Lead frame structure

[0052] Figure 1 It is a plan view showing the surface of the lead frame 10 according to the first embodiment. Figure 2 It is a plan view showing the back surface of the lead frame 10 according to the first embodiment. Figure 3 For along Figure 1 In the following description, the "front" refers to the side on which the semiconductor element 21 described later is placed, and the "back" refers to the side on the opposite side of the placement surface where the semiconductor element 21 is placed. Figure 2 In the figure, the half-etched portion is indicated by oblique lines.

[0053] like Figures 1 to 3 As shown, the lead frame 10 is a frame for manufacturing a semiconductor device 20 described later, and includes a plurality of lead frame units 14 arranged in a matrix in the X direction and the Y direction.

[0054] Each lead frame unit 14 is a region corresponding to each semiconductor device 20. Each lead frame unit 14 has a die pad 15, and a plurality of long lead portions 16A and a plurality of short lead portions 16B arranged around the die pad 15. Figure 1 and Figure 2 In FIG. 1 , regions surrounded by two-dot chain lines correspond to the lead frame units 14. In addition, the plurality of long lead portions 16A and the short lead portions 16B are examples of lead portions.

[0055] The die pad 15 has a placement surface for placing the semiconductor element 21 and is generally rectangular in shape when viewed from above. In addition, each long pin portion 16A and each short pin portion 16B are terminals connected to the semiconductor element 21 through a bonding wire 22 described later, and are configured to be separated from the die pad 15 by a space.

[0056] In addition, if Figure 1 and Figure 2 As shown, each long pin portion 16A and each short pin portion 16B extend along the X direction or the Y direction. In addition, the length of each long pin portion 16A is longer than that of each short pin portion 16B. In addition, each long pin portion 16A and each short pin portion 16B are alternately arranged around the die pad 15.

[0057] Each long pin portion 16A and each short pin portion 16B includes: an internal terminal portion 16a having a relatively wide width and connected to the bonding wire 22; and a connecting portion 16b having a relatively narrow width. The internal terminal portion 16a is provided on the surface of each long pin portion 16A and each short pin portion 16B. The internal terminal portion 16a is provided with a plating portion 25 for improving the adhesion between it and the bonding wire 22. In addition, an external terminal portion 16c (see FIG. 1 ) connected to an external circuit substrate (not shown) is provided on the back of each long pin portion 16A and each short pin portion 16B. Figure 3 That is, on the surface side of each long lead portion 16A and each short lead portion 16B, the internal terminal portions 16a are arranged in a zigzag shape (see Figure 1 ), the external terminals 16c on the back side are arranged in a zigzag shape (see Figure 2 The external terminal portions 16 c of the long lead portions 16A and the short lead portions 16B are portions exposed from the encapsulating resin on the back surface of the lead frame 10 after the semiconductor element 21 is encapsulated with the encapsulating resin for molding.

[0058] A plurality of connection bars 17 are arranged in a grid pattern around the lead frame unit 14. In each lead frame unit 14, the die pad 15 is connected to the connection bar 17 via four supporting legs 43 extending from the corners of the die pad 15.

[0059] The connecting bar 17 is arranged between adjacent lead frame units 14 and extends in a direction orthogonal to the length direction of the long pin portion 16A and the short pin portion 16B, connecting a corresponding pair of long pin portions 16A and connecting a corresponding pair of short pin portions 16B. For example, a plurality of long pin portions 16A and a plurality of short pin portions 16B extending in the X direction are connected to the connecting bar 17 extending in the Y direction. Here, the corresponding pair of long pin portions 16A (short pin portions 16B) is a pair of long pin portions 16A (short pin portions 16B) that are adjacent to each other in the length direction of the long pin portion 16A (short pin portion 16B) through the connecting bar 17. For example, in Figure 3 In the embodiment, the corresponding pair of long lead portions 16A is a pair of long lead portions 16A adjacent to each other in the X direction via the connection bar 17 .

[0060] like Figures 1 to 3 As shown, the connection bar 17 has a plurality of long pin connection portions 18A, a plurality of short pin connection portions 18B, and a plurality of middle portions 19 .

[0061] Each long pin connection portion 18A is located between a corresponding pair of long pin portions 16A, and each short pin connection portion 18B is located between a corresponding pair of short pin portions 16B. Figure 3 In the embodiment, each long pin connection portion 18A is located between a pair of long pin portions 16A arranged in the X direction. The middle portion 19 is located between the long pin connection portion 18A and the short pin connection portion 18B adjacent to each other. That is, the long pin connection portion 18A, the middle portion 19, and the short pin connection portion 18B are arranged in the order of the long pin connection portion 18A, the middle portion 19, the short pin connection portion 18B, the middle portion 19, the long pin connection portion 18A, etc. along the length direction of the connecting bar 17.

[0062] Figure 4A This is a partially enlarged plan view showing an enlarged view of the back side of the connecting bar 17 according to the first embodiment. Figure 4B 1 is a cross-sectional view of the long lead connecting portion 18A of the connection bar 17 according to the first embodiment. Figure 4C 1 is a cross-sectional view of the short pin connection portion 18B of the connection bar 17 according to the first embodiment. Figure 4B Equivalent to following Figure 4A The cross-sectional view of the IVB-IVB line, Figure 4C Equivalent to following Figure 4A Cross-sectional view of the IVC-IVC line.

[0063] like Figure 4A and Figure 4B As shown, the connecting bar 17 has a surface 17a located on the placement surface side of the die pad 15 and a back surface 17b located on the opposite side of the placement surface of the die pad 15. The back surface 17b of the connecting bar 17 corresponds to the bottom surface of the recess formed by half-etching the back surface of the lead frame 10.

[0064] like Figure 4A and Figure 4B As shown, the back surface 17b of the connection bar 17 is located between the front surface (i.e., the surface provided with the internal terminal portion 16a) and the back surface (i.e., the surface provided with the external terminal portion 16c) of each long lead portion 16A and each short lead portion 16B.

[0065] The back surface 17b of the connection bar 17 is provided with a protrusion 53. The protrusion 53 protrudes from the back surface 17b of the connection bar 17 to a position that does not reach the same surface as the back surface of each long pin portion 16A and each short pin portion 16B (i.e., the surface provided with the external terminal portion 16c). That is, the front end of the protrusion 53 is located between the back surface of each long pin portion 16A and each short pin portion 16B (i.e., the surface provided with the external terminal portion 16c) and the back surface 17b of the connection bar 17. In other words, the front end of the protrusion 53 is retracted toward the back surface 17b of the connection bar 17 relative to the same surface as the back surface of each long pin portion 16A and each short pin portion 16B (i.e., the surface provided with the external terminal portion 16c).

[0066] In addition, if Figure 4A As shown in FIG. 1 , the protrusion 53 extends linearly along the extending direction of the connecting strip 17. Figure 4B and Figure 4C As shown, the protrusion 53 is formed in the area corresponding to the long pin connection part 18A and the short pin connection part 18B in the back surface 17 b of the connection bar 17 .

[0067] In addition, in the manufacturing process of the QFN type semiconductor device 20, after the plastic molding, a solder plating process for forming a solder plating film may be performed on the portion of the back surface of the lead frame 10 exposed from the molding resin. For example, the external terminal portion 16c of each long lead portion 16A and each short lead portion 16B is a portion exposed from the molding resin, and a solder plating film is formed on the external terminal portion 16c of each long lead portion 16A and each short lead portion 16B by performing an outer plating process.

[0068] Here, a structure in which a portion that has not been half-etched remains on the back side 17b of the connecting bar 17 as in the technique described in Patent Document 1 is considered. In this structure, the portion that has not been half-etched is located on the same surface as the external terminal portion 16c of each long lead portion 16A and each short lead portion 16B, and is therefore exposed from the encapsulation resin on the back side of the lead frame 10. Therefore, if the outer plating process is performed, a solder plating film is formed on the portion that has not been half-etched on the back side 17b of the connecting bar 17. Therefore, when the cutting process is performed, the cutting blade cuts the solder plating film together with the connecting bar 17. As a result, there is a possibility that the solder plating film adheres to the blade edge of the cutting blade and causes clogging.

[0069] Therefore, if Figure 3 , Figure 4B and Figure 4C As shown, in the lead frame 10, a protrusion 53 is provided on the back surface 17b of the connecting bar 17, and its front end is located between the back surface of each long lead portion 16A and each short lead portion 16B and the back surface 17b of the connecting bar 17. Thus, the lead frame 10 can be realized which can prevent the dicing blade from being blocked during dicing.

[0070] That is, the front end of the protrusion 53 is retracted toward the back surface 17b of the connecting bar 17 relative to the same surface as the back surface of each long pin portion 16A and each short pin portion 16B (i.e., the surface provided with the external terminal portion 16c). Therefore, the protrusion 53 is not exposed from the encapsulation resin on the back surface of the lead frame 10, and a solder plating film is not formed on the protrusion 53 after the outer plating treatment. As a result, it is possible to suppress the solder plating film from adhering to the blade of the cutting blade during the cutting process of cutting the connecting bar 17. As a result, it is possible to realize the lead frame 10 that can prevent the cutting blade from clogging during the cutting process. In addition, even when the back surface 17b formed by half etching is formed on the connecting bar 17, the thickness of the connecting bar 17 can be maintained by the protrusion 53. As a result, it is possible to maintain the rigidity of the connecting bar 17 and prevent the cutting blade from clogging during the cutting process.

[0071] Structure of semiconductor device

[0072] Next, refer to Figure 5 and Figure 6 A semiconductor device 20 produced using the lead frame 10 according to the first embodiment will be described. Figure 5 This is a plan view showing the surface of a semiconductor device 20 manufactured using the lead frame 10 according to the first embodiment. Figure 6 For along Figure 5 Cross-sectional view along line VI-VI.

[0073] Figure 5 and Figure 6 The semiconductor device 20 shown has a die pad 15, a long lead portion 16A and a short lead portion 16B, and a semiconductor element 21 placed on the placement surface of the die pad 15. In addition, the semiconductor device 20 has a bonding wire 22 that electrically connects the long lead portion 16A and the short lead portion 16B to a terminal portion 21a of the semiconductor element 21. In addition, the die pad 15, the long lead portion 16A, the short lead portion 16B, the semiconductor element 21, and the bonding wire 22 are encapsulated by an encapsulation resin 24.

[0074] The semiconductor element 21 is, for example, an integrated circuit, a large-scale integrated circuit, a transistor, a thyristor, a diode, etc. The semiconductor element 21 is fixed to the placement surface of the die pad 15 by an adhesive material such as a die bonding paste. In addition, when the adhesive material is a die bonding paste, for example, a die bonding paste made of epoxy resin or silicone resin can be selected.

[0075] Each bonding wire 22 is made of a conductive material such as gold or copper, and one end thereof is connected to each terminal portion 21 a of the semiconductor element 21 , and the other end thereof is connected to each long lead portion 16A and each short lead portion 16B.

[0076] As the encapsulation resin 24, for example, epoxy resin or silicone resin can be used. The external terminal portion 16c of each long lead portion 16A and each short lead portion 16B is exposed from the encapsulation resin 24 to the back side of the semiconductor device 20. The external terminal portion 16c of each long lead portion 16A and each short lead portion 16B is covered by a solder plating film 26 as an outer layer of the semiconductor device 20. In addition, the back side of the die pad 15 opposite to the placement surface is also exposed from the encapsulation resin 24 and covered by the solder plating film 26.

[0077] Lead frame manufacturing method

[0078] Next, refer to 7A to 7H ,illustrate Figures 1 to 3 , Figure 4A and Figure 4B A method of manufacturing the lead frame 10 is shown. 7A to 7H It is a cross-sectional view showing a method of manufacturing the lead frame 10 according to the first embodiment. 7A to 7H The cross-sectional view shown is Figure 3 The corresponding figure.

[0079] First, if Fig. 7A As shown in FIG. 1 , a flat metal plate 31 is prepared. As the material of the metal plate 31, a metal such as copper can be used.

[0080] Then, if Figure 7B As shown in FIG. 1 , photoresists 32a and 33a are applied to the entire surface and the entire back surface of the metal plate 31, respectively, and then dried.

[0081] Then, if Figure 7C As shown, the photoresists 32a and 33a are exposed using photomasks 34 and 35 having predetermined patterns.

[0082] Then, if Fig.7DAs shown, by developing the exposed photoresists 32a and 33a, photoresist layers 32 and 33 having predetermined openings are formed. Specifically, on the surface side of the metal plate 31, an opening 32b is formed in a portion where through etching is performed. On the other hand, on the back side of the metal plate 31, an opening 33b is formed in a portion where through etching is performed and a portion where half etching is performed. In addition, on the back side of the metal plate 31, an opening 33b is formed in a manner that a portion of the photoresist 33c for suppressing corrosion by the etching liquid remains at a position corresponding to the protrusion 53 of the connecting bar 17.

[0083] Then, if Fig. 7E As shown, the metal plate 31 is etched with an etching liquid using the photoresist layers 32 and 33 as masks (corrosion-resistant masks). A suitable etching liquid can be selected according to the material of the metal plate 31 used. For example, when copper is used as the metal plate 31, an aqueous solution of ferric chloride can be used. The etching of the metal plate 31 is performed, for example, by spraying the etching liquid onto the surface and back of the metal plate 31 with a sprayer. Thus, a plurality of lead frame units 14 are formed on the metal plate 31, and the plurality of lead frame units 14 respectively include: a chip pad 15 having a placement surface for placing the semiconductor element 21; and a plurality of long pin portions 16A and a plurality of short pin portions 16B arranged around the chip pad 15. In addition, when forming a plurality of lead frame units 14, a connecting bar 17 having a long pin connecting portion 18A, a short pin connecting portion 18B, and an intermediate portion 19 is formed between adjacent lead frames 14. In addition, when forming a plurality of lead frame units 14, the back surface 17b of the connecting bar 17 is formed so as to be located between the front surface and the back surface of each long lead portion 16A and each short lead portion 16B. Furthermore, when forming a plurality of lead frame units 14, the etching liquid enters from the openings 33b on both sides of the partial photoresist 33c and corrodes the metal plate 31. As a result, a protrusion 53 is formed on the back surface 17b of the connecting bar 17, the front end of which is located between the front surface of each long lead portion 16A and each short lead portion 16B and the back surface 17b of the connecting bar 17.

[0084] Then, if Figure 7F As shown, the photoresist layers 32 and 33 are stripped and removed.

[0085] Then, if Figure 7GAs shown in the figure, the internal terminal portions 16a of the long lead portion 16A and the short lead portion 16B are respectively plated (e.g., electroplated) to form the plated portion 25. The plated portion 25 can be of any type as long as it can ensure the close adhesion with the bonding wire 22, for example, it can be a single-layer plating such as Ag or Au, or a multi-layer plating in which Ni / Pd or Ni / Pd / Au is stacked in sequence. In addition, the plated portion 25 can be formed only at the connecting portion connected to the bonding wire 22 in the internal terminal portion 16, or it can be formed on the entire surface of the lead frame 10. In the above manner, the lead frame 10 of this embodiment can be manufactured.

[0086] Then, if Figure 7H As shown, the lead frame 10 is placed on the back tape 37 for fixation.

[0087] Method for manufacturing semiconductor device

[0088] Next, refer to FIG. 8A to FIG. 8H ,illustrate Figure 5 and Figure 6 A method for manufacturing the semiconductor device 20 is shown. FIG. 8A to FIG. 8H It is a cross-sectional view showing a method for manufacturing the semiconductor device 20 according to the first embodiment. FIG. 8A to FIG. 8H The cross-sectional view shown is Figure 6 The corresponding figure.

[0089] First, if Fig. 8A As shown in FIG. 1 , a lead frame 10 is manufactured, which includes a die pad 15 and a plurality of long lead portions 16A and a plurality of short lead portions 16B arranged around the die pad 15. The lead frame 10 is formed by 7A to 7H It is made by the process shown.

[0090] Then, if Figure 8B As shown in FIG. 1 , a semiconductor element 21 is placed on the die pad 15 of the lead frame 10. At this time, the semiconductor element 21 is placed on the placement surface of the die pad 15 and fixed using an adhesive material such as a die bonding paste. Figure 8B The process shown may be referred to as "die attach".

[0091] Then, if Figure 8C As shown in FIG. 1 , the terminal portion 21a of the semiconductor element 21 is electrically connected to each of the long lead portions 16A and each of the short lead portions 16B of the lead frame 10 by the bonding wire 22. The bonding wire 22 is an example of a connecting portion. Figure 8C The process shown may be referred to as "wire bonding".

[0092] Then, if Fig.8DAs shown in FIG. 1 , the die pad 15, the long lead portion 16A, the short lead portion 16B, the semiconductor element 21, and the bonding wire 22 are encapsulated with the encapsulating resin 24. Thus, the back surface 17b of the connecting bar 17 is filled with the encapsulating resin 24, and the protrusion 53 is covered with the encapsulating resin 24. Fig.8D The process shown may be referred to as "molding".

[0093] Then, if Fig. 8E As shown, the backing tape 37 is peeled off from the back surface of the lead frame 10 .

[0094] Then, if Fig.8F As shown, a solder plating film 26 is formed on the portion exposed from the encapsulating resin 24 on the back side of the lead frame 10. The solder plating film 26 is formed, for example, by electroplating. For example, the external terminal portion 16c of each long pin portion 16A and each short pin portion 16B is exposed from the encapsulating resin 24 on the back side of the lead frame 10. Therefore, a solder plating film 26 is formed on the external terminal portion 16c of each long pin portion 16A and each short pin portion 16B. Examples of the solder plating film 26 include a lead plating film, a lead-bismuth plating film, a lead-silver plating film, and the like. In addition, the back side of the chip pad 15 on the opposite side to the placement surface is also exposed from the encapsulating resin 24. Therefore, a solder plating film 26 is formed on the back side of the chip pad 15 on the opposite side to the placement surface. In contrast, the protrusion 53 is not exposed from the encapsulating resin 24 on the back side of the lead frame 10. Therefore, a solder plating film 26 is not formed on the protrusion 53. Fig.8F The process shown may be referred to as "exterior plating process".

[0095] Then, if Figure 8G As shown in FIG. 1 , the connecting bars 17 and the encapsulating resin 24 between adjacent lead frame units 14 are cut by a cutting blade 38 to separate the lead frame 10 into the lead frame units 14. Figure 8G The process shown can be called "cutting processing".

[0096] Specifically, the connecting bar 17 and the encapsulating resin 24 between the adjacent lead frame units 14 are cut by moving the cutting blade 38 such as a diamond wheel along the extending direction of the connecting bar 17. In the present embodiment, the solder plating film 26 is not formed on the protruding portion 53 formed on the back surface 17b of the connecting bar 17. Therefore, when the connecting bar 17 is cut by the cutting blade 38, the protruding portion 53 on which the solder plating film 26 is not formed is cut by the cutting blade 38, and the solder plating film 26 can be suppressed from being attached to the blade edge of the cutting blade 38. Thus, the cutting blade 38 can be prevented from being clogged.

[0097] like Figure 8H As shown, the semiconductor device 20 of the present embodiment is manufactured in the above-described manner.

[0098] As described above, the lead frame 10 involved in the first embodiment includes a plurality of long pin portions 16A and a plurality of short pin portions 16B, a connecting bar 17, and a protrusion 53. The plurality of long pin portions 16A and the plurality of short pin portions 16B have a front surface (i.e., a surface provided with the internal terminal portion 16a) and a back surface (i.e., a surface provided with the external terminal portion 16c). The connecting bar 17 has a front surface 17a and a back surface 17b, and is connected to the long pin portions 16A and the short pin portions 16B. The protrusion 53 is provided on the back surface 17b of the connecting bar 17. The back surface 17b of the connecting bar 17 is located between the front surface (i.e., a surface provided with the internal terminal portion 16a) and the back surface (i.e., a surface provided with the external terminal portion 16c) of each long pin portion 16A and each short pin portion 16B. The front end of the protrusion 53 is located between the back surface of each long lead portion 16A and each short lead portion 16B (ie, the surface provided with the external terminal portion 16 c ) and the back surface 17 b of the connection bar 17 .

[0099] According to the structure of the lead frame 10, the front end of the protrusion 53 can be set back toward the back surface 17b of the connecting bar 17 relative to the same surface as the back surface of each long lead portion 16A and each short lead portion 16B (that is, the surface provided with the external terminal portion 16c). Therefore, the protrusion 53 is not exposed from the encapsulation resin 24 on the back surface of the lead frame 10, and the solder plating film 26 is not formed on the protrusion 53 after the outer plating process. Therefore, it is possible to suppress the solder plating film 26 from adhering to the blade of the dicing blade 38 during the cutting process of cutting the connecting bar 17. As a result, it is possible to realize the lead frame 10 that can prevent the dicing blade 38 from being blocked during the cutting process. In addition, even when the back surface 17b formed by half etching is formed on the connecting bar 17, the thickness of the connecting bar 17 is maintained by the protrusion 53. As a result, it is possible to maintain the rigidity of the connecting bar 17 and prevent the dicing blade 38 from being blocked during the cutting process.

[0100] Furthermore, in the lead frame 10 , the protrusion 53 extends linearly along the extending direction of the connection bar 17 .

[0101] According to the structure of the lead frame 10 , the rigidity of the connecting bar 17 can be increased over the entire region in the extending direction of the connecting bar 17 .

[0102] In the lead frame 10, the connection bar 17 has a plurality of long pin connection portions 18A located between a corresponding pair of long pin portions 16A and a plurality of short pin connection portions 18B located between a corresponding pair of short pin portions 16B. The protrusion 53 is formed in the back surface 17b of the connection bar 17 in the region corresponding to the long pin connection portions 18A and the short pin connection portions 18B.

[0103] According to the structure of the lead frame 10 , the rigidity of the portions where stress concentration occurs in the tie bar 17 , namely, the long lead connecting portion 18A and the short lead connecting portion 18B can be improved.

[0104] Example 2

[0105] Next, Example 2 will be described. The lead frame 10A according to Example 2 has the same structure as the lead frame 10 according to Example 1, except for the arrangement of the protrusions 53 on the long lead connecting portion 18A and the short lead connecting portion 18B. Therefore, in Example 2, the same reference numerals are used for the components common to Example 1, and detailed description thereof is omitted.

[0106] Fig.9A This is a partially enlarged plan view showing an enlarged view of the back side of the connecting bar 17 according to the second embodiment. Fig. 9B 1 is a cross-sectional view of the long lead connecting portion 18A of the connection bar 17 according to the second embodiment. Fig. 9C 1 is a cross-sectional view of a short pin connection portion 18B of a connection bar 17 according to the second embodiment. Fig. 9B Equivalent to following Fig.9A The cross-sectional view of the IXB-IXB line, Fig. 9C Equivalent to following Fig.9A Cross-sectional view of the IXC-IXC line.

[0107] like Fig.9A As shown in FIG. 1 , the protrusion 53 is arranged in an island shape along the extending direction of the connecting strip 17. Fig. 9B As shown, the protrusion 53 is formed in the area corresponding to the long pin connection portion 18A in the back surface 17b of the connection bar 17. Fig. 9C As shown, the protrusion 53 is not formed in the area corresponding to the short pin connecting portion 18B in the back surface 17 b of the connection bar 17 .

[0108] According to the lead frame 10A according to the second embodiment, the rigidity of the long lead connecting portion 18A, which is the portion where the greatest stress concentration occurs in the tie bar 17 , can be increased.

[0109] Example 3

[0110] Next, Example 3 will be described. A lead frame 10B according to Example 3 has the same structure as the lead frame 10 according to Example 1 except that the plurality of long lead portions 16A are omitted. Therefore, in Example 3, the same reference numerals are used for the components common to Example 1, and detailed description thereof is omitted.

[0111] Fig.10 It is a plan view showing the surface of the lead frame 10B according to the third embodiment. Fig.11 It is a plan view showing the back surface of the lead frame 10B according to the third embodiment. Fig.12 This is a partially enlarged plan view showing an enlarged view of the back side of the connecting bar 17 according to the third embodiment.

[0112] exist Fig.10 and Fig.11 In the lead frame 10B shown, each lead frame unit 14 has a die pad 15 and a short lead portion 16B arranged around the die pad 15. That is, the lead frame 10B is different from the lead frame 10 of the first embodiment in that a plurality of long lead portions 16A (see Figure 1 and Figure 2 The plurality of short lead portions 16B are an example of a lead portion. In the lead frame 10B, each intermediate portion 19 is located between the short lead connecting portions 18B adjacent to each other.

[0113] In the lead frame 10B, a protrusion 53 is provided on the back surface 17b of the connecting bar 17, the tip of which is located between the back surface of each short lead portion 16B and the back surface 17b of the connecting bar 17. This can maintain the rigidity of the connecting bar 17 and prevent the dicing blade 38 from being blocked during the dicing process.

[0114] In addition, if Fig.12 As shown, the protrusion 53 extends linearly along the extending direction of the connecting bar 17. The rigidity of the connecting bar 17 can be improved in the entire area in the extending direction of the connecting bar 17.

[0115] Example 4

[0116] Next, Example 4 will be described. A lead frame 10C according to Example 4 has the same structure as the lead frame 10B according to Example 3 except for the arrangement of the protrusions 53. Therefore, in Example 4, the same reference numerals are used for the components common to Example 3, and detailed description thereof is omitted.

[0117] Fig.13 This is a partially enlarged plan view showing an enlarged view of the back side of the connecting bar 17 according to the fourth embodiment.

[0118] like Fig.13 As shown in FIG. 1 , in the lead frame 10C, the protrusion 53 is arranged in an island shape along the extending direction of the connection bar 17. That is, the protrusion 53 is formed in the area corresponding to the short lead connecting portion 18B on the back surface 17b of the connection bar 17. On the other hand, the protrusion 53 is not formed in the area corresponding to the middle portion 19 on the back surface 17b of the connection bar 17.

[0119] According to the lead frame 10C according to the fourth embodiment, the rigidity of the short lead connection portion 18B, which is a portion where stress concentration occurs in the tie bar 17, can be increased.

[0120] Example 5

[0121] Next, Example 5 will be described. A lead frame 10D according to Example 5 has the same structure as the lead frame 10B according to Example 3 except for the arrangement of the protrusions 53. Therefore, in Example 5, the same reference numerals are used for the components common to Example 3, and detailed description thereof is omitted.

[0122] Fig.14 This is a partially enlarged plan view showing an enlarged view of the back side of the connecting bar 17 according to the fifth embodiment.

[0123] like Fig.14 As shown in FIG. 1 , in the lead frame 10D, the protrusion 53 is arranged in an island shape along the extending direction of the connection bar 17. That is, the protrusion 53 is formed in the area corresponding to the middle part 19 on the back side 17b of the connection bar 17. On the other hand, the protrusion 53 is not formed in the area corresponding to the short lead connecting part 18B on the back side 17b of the connection bar 17.

[0124] According to the lead frame 10D according to the fifth embodiment, even when the width of the connecting bar 17 is narrow and the protrusion 53 cannot be provided in the region corresponding to the short lead connecting portion 18B on the back surface 17 b , the rigidity of the connecting bar 17 can be improved.

[0125] Example 6

[0126] Lead frame structure

[0127] Fig.15 It is a plan view showing the surface of the lead frame 10E according to the sixth embodiment. Fig.16 For along Fig.15 The lead frame 10E according to the sixth embodiment has the same structure as the lead frame 10 according to the first embodiment except that the die pad 15 and the support pins 43 are omitted. Therefore, in the sixth embodiment, the same reference numerals are used for the components common to the first embodiment, and their detailed description is omitted.

[0128] exist Fig.15 and Fig.16 In the lead frame 10E shown, each lead frame unit 14 has a plurality of long lead portions 16A and a plurality of short lead portions 16B. That is, the lead frame 10E is different from the lead frame 10 of the first embodiment in that the die pad 15 and the support legs 43 are omitted.

[0129] Structure of semiconductor device

[0130] Next, refer to Fig.17 A semiconductor device 20E manufactured using the lead frame 10E according to the sixth embodiment will be described. Fig.17It is a side cross-sectional view showing an example of the structure of a semiconductor device 20E manufactured using the lead frame 10E according to the sixth embodiment.

[0131] Fig.17 The semiconductor device 20E shown has a long lead portion 16A and a short lead portion 16B, and a semiconductor element 21 placed on the long lead portion 16A and the short lead portion 16B. In addition, the semiconductor device 20E has a bump 27 that electrically connects the long lead portion 16A and the short lead portion 16B to the semiconductor element 21. In addition, the long lead portion 16A, the short lead portion 16B, the semiconductor element 21, and the bump 27 are encapsulated by an encapsulation resin 24.

[0132] The semiconductor element 21 is, for example, an integrated circuit, a large-scale integrated circuit, a transistor, a thyristor, a diode, etc. The semiconductor element 21 is fixed to the long lead portion 16A and the short lead portion 16B via bumps 27 .

[0133] The bumps 27 are made of solder, for example, and have upper surfaces connected to the respective terminal portions of the semiconductor element 21 , and lower surfaces connected to the respective long lead portions 16A and the respective short lead portions 16B.

[0134] For example, epoxy resin or silicone resin can be used as the encapsulation resin 24. The external terminal portion 16c of each long lead portion 16A and each short lead portion 16B is exposed from the encapsulation resin 24 on the back surface of the semiconductor device 20E. The external terminal portion 16c of each long lead portion 16A and each short lead portion 16B is covered by a solder plating film 26 as an outer peripheral layer of the semiconductor device 20E.

[0135] In the lead frame 10E, a protrusion 53 is provided on the back surface 17b of the connecting bar 17, the tip of which is located between the back surfaces of the long lead portions 16A and the short lead portions 16B and the back surface 17b of the connecting bar 17. Thus, the rigidity of the connecting bar 17 can be maintained, and clogging of the dicing blade 38 can be prevented during dicing.

Claims

1. A lead frame, characterized in that: include: A pin portion having a one side surface and another side surface; A connecting bar having a one side surface and another side surface, wherein the pin portion is connected to the connecting bar; as well as A protrusion is arranged on a side surface of the connecting strip, wherein: One side surface of the connecting strip is located between one side surface and the other side surface of the pin portion. The front end of the protrusion is located between one side surface of the pin portion and one side surface of the connecting bar. The protrusion protrudes from one side surface of the connection bar to a position that does not reach the same plane as one side surface of the external terminal portion where the lead portion is provided.

2. The lead frame according to claim 1, characterized in that: Also includes: A chip pad has a placement surface for placing a semiconductor element.

3. The lead frame according to claim 1, wherein: Also includes: Each of the plurality of lead frame units includes a die pad having a placement surface for placing a semiconductor element, and a plurality of the lead portions arranged around the die pad.

4. The lead frame according to claim 1, wherein: The protrusion extends linearly along the extending direction of the connecting strip.

5. The lead frame according to claim 4, characterized in that: The pin portion includes: a plurality of relatively long pin portions, and a plurality of relatively short pin portions. The connecting bar extends in a direction perpendicular to the length direction of the long pin portion and the short pin portion, and connects a corresponding pair of the long pin portions and a corresponding pair of the short pin portions. The connecting strip comprises: a plurality of long pin connection portions located between a corresponding pair of the long pin portions; and A plurality of short pin connection portions, which are located between a corresponding pair of the short pin portions, The protrusion is formed in a region of a side surface of the connection bar corresponding to the long pin connection portion and the short pin connection portion.

6. The lead frame according to claim 1, wherein: The protrusion is arranged in an island shape along the extending direction of the connecting bar.

7. The lead frame according to claim 6, characterized in that The pin portion includes: a plurality of relatively long pin portions, and a plurality of relatively short pin portions. The connecting bar extends in a direction perpendicular to the length direction of the long pin portion and the short pin portion, and connects a corresponding pair of the long pin portions and a corresponding pair of the short pin portions. The connecting strip comprises: a plurality of long pin connection portions located between a corresponding pair of the long pin portions; and A plurality of short pin connection portions, which are located between a corresponding pair of the short pin portions, The protrusion is formed in a region of a side surface of the connection bar corresponding to the long pin connection portion.

8. The lead frame according to any one of claims 1 to 7, characterized in that: An external terminal portion connected to an external circuit substrate is provided on one side surface of the lead portion. An internal terminal portion connected to a connection portion for electrically connecting the semiconductor element to the lead portion is provided on the other side surface of the lead portion.

9. A method for manufacturing a lead frame, characterized in that: Including the following processes: forming a photoresist layer on the metal plate; The metal plate is etched by using the photoresist layer as a mask to form on the metal plate: a pin portion having one side surface and another side surface; a connecting bar having one side surface and another side surface, the pin portion being connected to the connecting bar; and a protrusion portion provided on one side surface of the connecting bar; as well as The photoresist layer is removed from the metal plate, wherein One side surface of the connecting strip is located between one side surface and the other side surface of the pin portion. The front end of the protrusion is located between one side surface of the pin portion and one side surface of the connecting bar. The protrusion protrudes from one side surface of the connection bar to a position that does not reach the same plane as one side surface of the external terminal portion where the lead portion is provided.

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