Lead frame, manufacturing method thereof and semiconductor device

Abstract

To provide a lead frame in which an area occupied by a mold lock is narrow, provide a manufacturing method of the lead frame with which a limitation of a position where the mold lock can be formed is reduced and which is simplified, and provide a semiconductor device capable of attaining downsizing.SOLUTION: A lead frame comprises a groove part 3 and a thin part 6. A wall part in a portion of the groove part 3 is positioned within the thin part 6. A wall part 31A which is positioned within the thin part 6 includes a protrusion 32 which protrudes toward an opposed wall part 31 and includes an overhand part 33. A manufacturing method of the lead frame includes forming the groove part 3 and the thin part 6 by pressing a bottom face of a lead frame 100 in which a recess is formed on a top face. In a semiconductor device, a semiconductor element is placed on the top face of the lead frame 100, and the inside of the groove part 3 is filled with a mold resin so as to reach the overhang part 33.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a lead frame having excellent adhesion to a molding resin, a manufacturing method thereof, and a semiconductor device. [Background technology]

[0002] Since a semiconductor device sealed with a mold resin is made of materials with different elastic moduli and thermal expansion coefficients, thermal stress occurs due to temperature changes applied to the semiconductor device. For example, in the sealing process of a semiconductor device, a lead frame on which a semiconductor element is mounted is set in a mold die heated to about 170°C, and a thermosetting mold resin is injected into the die to seal the semiconductor device. A semiconductor device sealed with a resin at a high temperature is in a state in which residual stress occurs at room temperature. When a resin-sealed semiconductor device is mounted on a motherboard or the like, the semiconductor device is heated to about 240°C due to heating of the adhesive material, and thermal stress occurs. Furthermore, when an electronic device in which a semiconductor device is incorporated is used in an environment of about -50°C, thermal stress also occurs in the semiconductor device. When the thermal stress (mainly shear stress) generated by such a temperature change becomes larger than the adhesive strength between the mold resin and the lead frame, the mold resin peels off from the surface of the lead frame. In addition, the peeling of the mold resin occurs not only due to the above-mentioned thermal stress, but also when, for example, a solution used in a plating process gets between the mold resin and the lead frame.

[0003] If the mold resin peels off from the surface of the lead frame, moisture and the like will penetrate into the inside of the semiconductor device, reducing the moisture resistance and the reliability of the semiconductor device. Therefore, a technique has been proposed for forming a mold lock on the lead frame to improve the adhesion between the mold resin and the lead frame. For example, Patent Document 1 discloses a lead frame equipped with a dimple as a mold lock, and a method for manufacturing the dimple by pressing. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 07-161896 Summary of the Invention [Problem to be solved by the invention]

[0005] A method of forming a mold lock in a lead frame using a mold is a highly productive and inexpensive method. Figs. 11 to 13 are explanatory diagrams of a related art method of manufacturing a lead frame with a mold lock. As shown in Fig. 11, a metal plate 8 is placed on the lower surface of a lead frame 100a, and a mold 9a presses the lead frame 100a downward (in the direction of the arrow) from the upper surface of the lead frame 100a, deforming the lead frame 100a into a concave shape to a depth of about 1 / 4 to 1 / 2 the thickness of the lead frame 100a, thereby forming a recess 7a. For example, the tip of the mold 9a is made rectangular to form the recess 7a having a rectangular opening.

[0006] Next, as shown in Fig. 12, the lead frame 100a is pressed downward (in the direction of the arrow) from the top surface of the lead frame 100a with the mold 9b along the long side of the rectangular opening of the recess 7a, deforming it into a V-shape. As a result, the recess 7b is formed as shown in Fig. 13, and at the same time, a part of the wall 71 of the recess 7a is deformed to form an inclined wall 72. The recesses 7a and 7b function as mold locks, and when the molding resin is filled into the recess 7a so as to reach the inclined wall 72, the recess 7a having the inclined wall 72 in particular has an anchor effect, improving the adhesion between the molding resin and the lead frame 100a.

[0007] However, when the recesses 7a and 7b are arranged on the upper surface of the lead frame 100a, the width w1 shown in FIG. 13 becomes wider. As an example, the width w1 needs to be about 0.16 to 2.00 mm, and the area occupied by the mold lock composed of the recesses 7a and 7b on the lead frame 100a becomes wider. FIG. 14 shows an explanatory diagram of another lead frame equipped with a mold lock according to the related art. When the recess 7a and the recesses 7b on both sides are arranged on the upper surface of the lead frame 100b to further improve the adhesion between the mold resin and the lead frame 100b, the width w2 shown in FIG. 14 becomes wider than the width w1 shown in FIG. 13, and there is a problem that the area occupied by the mold lock on the lead frame 100b becomes even wider.

[0008] In addition, the manufacturing method of the lead frames 100a and 100b described above is a highly mass-producible and inexpensive manufacturing method because the mold lock can be formed simply by pressing the upper surface of the lead frame 100a, etc. with the molds 9a and 9b. However, the above method requires the metal plate 8 to be placed on the lower surface of the lead frame 100a, etc. In a typical lead frame, a thin portion (thin portion) that is expected to have an anchor effect may be placed around the die pad portion to prevent the lead frame from being pulled out of the mold resin. In this case, it is difficult to place the metal plate 8 so as to contact the thin portion, and it is difficult to form the recesses 7a and 7b shown in FIGS. 13 and 14 in the thin portion. Therefore, the positions where the recesses 7a and 7b can be formed are limited to positions other than the thin portion, specifically, positions where the semiconductor element of the die pad portion can be placed, and there is a problem that there is a restriction on the positions where the mold lock can be placed.

[0009] Furthermore, in a semiconductor device having the above-mentioned lead frame 100a or 100b, when a mold lock is arranged on the die pad portion of the lead frame 100a, etc., only a small semiconductor element can be mounted on the die pad portion. Therefore, in order to mount a large semiconductor element, the area of ​​the die pad portion must be made large, which poses a problem of preventing miniaturization of the semiconductor device.

[0010] Therefore, an object of the present invention is to provide a lead frame in which the area occupied by the mold lock is small, to provide a simple method for manufacturing a lead frame with fewer restrictions on the location where the mold lock can be formed, and to provide a semiconductor device that can be miniaturized. [Means for solving the problem]

[0011] A lead frame according to one embodiment of the present invention is a lead frame on which a semiconductor element is mounted and which is sealed with molded resin, and which comprises a groove portion arranged on one side of the lead frame which is located at a resin sealing portion which is sealed with molded resin, and a thin portion having a shape in which a portion of the other side opposite the one side of the lead frame which is located at the resin sealing portion is cut out, and some or all of the walls of the groove portion are located within the thin portion, and some or all of the walls located within the thin portion are configured to comprise a protrusion which protrudes toward the opposing wall portion and has an overhang portion at a portion of the depth direction of the groove portion.

[0012] Another aspect of the present invention is a method for manufacturing a leadframe, on which a semiconductor element is mounted and sealed with molded resin, comprising a recess forming step of forming a recess in one side of the leadframe located at a resin sealing portion sealed with molded resin, and a pressing step of pressing the other side opposite to the one side of the leadframe located at the resin sealing portion to form a thin portion and a groove portion, wherein the pressing step is configured to press a part of the leadframe including a position where some or all of the walls of the recess are projected onto the other side of the leadframe, thereby forming a thin portion in a shape where a part of the leadframe is cut out, and the some or all of the walls of the recess located within the thin portion protrude toward the opposing wall portions, respectively, and a portion of the recess in the depth direction forms an overhanging shape, thereby forming the groove portion.

[0013] Another aspect of the present invention is a semiconductor device comprising a lead frame, a semiconductor element mounted on the lead frame, and a resin portion in which the lead frame and the semiconductor element are sealed with molded resin, the lead frame comprising a groove portion disposed on one side of the lead frame located at the resin sealing portion sealed with the molded resin, and a thin portion having a shape in which a portion of the other side opposing the one side of the lead frame located at the resin sealing portion is cut out, some or all of the walls of the groove portion are located within the thin portion, and some or all of the walls located within the thin portion have a protruding portion that protrudes toward the opposing wall portion and has an overhang portion at a portion of the depth direction of the groove portion, the semiconductor element is mounted on the one side of the lead frame constituting a die pad portion, and the molded resin is filled in the groove portion so as to reach the overhang portion. Effect of the Invention

[0014] According to the lead frame of the present invention, the groove functioning as the mold lock is composed of a single recess, so that the mold lock occupies a small area on the lead frame. According to the manufacturing method of the lead frame of the present invention, the thin portion is formed and the groove is formed at the same time by the pressing process, so that some or all of the walls of the groove can be designed to be located within the thin portion, and there are few restrictions on the position where the groove can be formed, so that the lead frame can be manufactured easily. Furthermore, according to the semiconductor device of the present invention, the mold lock occupies a small area on the lead frame, so that there are few restrictions on the position where the groove can be formed, so that the semiconductor device can be miniaturized. [Brief description of the drawings]

[0015] [Figure 1] FIG. 1 is an explanatory diagram of one embodiment (embodiment 1) of a lead frame according to one aspect of the present invention. [Diagram 2] 2 is a schematic cross-sectional view of a groove portion of the lead frame taken along line AA in FIG. 1. [Diagram 3]FIG. 4 is an explanatory diagram of another embodiment (embodiment 2) of the lead frame according to an aspect of the present invention. [Figure 4] 4 is a schematic cross-sectional view of a groove portion taken along line BB of the lead frame in FIG. 3. [Diagram 5] FIG. 4 is an explanatory diagram of an embodiment (Embodiment 3) of a semiconductor device according to another aspect of the present invention. [Figure 6] FIG. 2 is an explanatory diagram of one embodiment (embodiment 1) of a method for producing a lead frame, which is still another aspect of the present invention. [Figure 7] 1A to 1C are explanatory diagrams of a manufacturing method of the lead frame of the first embodiment. [Figure 8] 1A to 1C are explanatory diagrams of a manufacturing method of the lead frame of the first embodiment. [Figure 9] FIG. 4 is an explanatory diagram of another embodiment (embodiment 2) of the lead frame manufacturing method which is still another aspect of the present invention. [Figure 10] 10A to 10C are explanatory diagrams of a manufacturing method of a lead frame according to a second embodiment. [Figure 11] 1A to 1C are explanatory diagrams of a manufacturing method of a lead frame having a mold lock according to a related art; [Figure 12] 1A to 1C are explanatory diagrams of a manufacturing method of a lead frame having a mold lock according to a related art; [Figure 13] 1A to 1C are explanatory diagrams of a manufacturing method of a lead frame having a mold lock according to a related art; [Figure 14] FIG. 2 is an illustration of another lead frame with a mold lock according to the related art. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Next, the embodiments of the lead frame and semiconductor device of the present invention and the embodiment of the manufacturing method of the lead frame will be described with reference to the drawings, but the present invention is not limited to these embodiments and embodiments, and the members, materials, etc. described below can be variously modified within the scope of the spirit of the present invention. Also, in the drawings, the same reference numerals indicate the same or equivalent items, and the size and positional relationship between each component are for convenience and may not strictly reflect the actual situation.

[0017] (Embodiment 1) First, an embodiment (embodiment 1) of a lead frame according to one aspect of the present invention will be described. FIG. 1 is an explanatory diagram of embodiment 1 of the lead frame according to the present invention. As shown in FIG. 1, the lead frame 100 of this embodiment is configured such that a plurality of lead terminals 1 and a header portion 2 are connected by connecting portions (not shown), and the header portion 2 is provided with a groove portion 3 that functions as a mold lock. 4 is a die pad portion of the header portion 2, 5 is a resin sealing portion in which a mold resin that seals the lead terminals 1 and the semiconductor element placed on the die pad portion 4 is formed when a semiconductor device is formed using the lead frame 100 of this embodiment, and 6 is a thin portion in a shape in which a part of the lead frame 100 is cut out. FIG. 2 is a schematic cross-sectional view of the groove portion 3 taken along the line AA of the lead frame 100 of FIG. 1.

[0018] 1 and 2, groove 3 has an opening on the top surface (one surface) of lead frame 100, and the shape of the opening at the top surface has a pair of opposing long sides and a pair of opposing short sides. Groove 3 is configured to include protruding portion 32 that protrudes toward wall portion 31, which is disposed opposite wall portion 31A shown in FIG. 2. Wall portion 31A is configured to include overhang portion 33 having a reverse tapered shape in the depth direction of groove 3. Protruding portion 32 and overhang portion 33 can be formed, for example, by manufacturing a lead frame according to a manufacturing method for a lead frame described below.

[0019] As shown in FIG. 2, when the lead frame 100 of this embodiment is used as a lead frame for a semiconductor device and a resin portion is formed from molded resin, the groove portion 3 with the overhang portion 33 fills the molded resin so that it reaches the overhang portion 33, and functions as a mold lock that enhances adhesion between the molded resin and the die pad portion 4 (lead frame) through an anchor effect.

[0020] Furthermore, lead frame 100 of this embodiment is configured to have thin portion 6 in which a part of the lower surface (the other surface) opposing the upper surface is cut out by forming groove portion 3 according to a lead frame manufacturing method described later. Furthermore, wall portion 31A including protrusion 32 is configured to be located within thin portion 6. As with a normal lead frame, thin portion 6 can increase the adhesion between the molded resin and die pad portion 4 by the anchor effect.

[0021] In this manner, the groove 3 functioning as a mold lock of the lead frame 100 of this embodiment is composed of only one recess. If the width W1 shown in FIG. 2 is equivalent to the opening width of the recess 7a described in FIG. 11, the width W1 is about 0.10 mm. This is very narrow compared to the width w1 including the recesses 7a and 7b described in FIG. 13, which is 0.16 to 2.00 mm. As a result, the lead frame 100 of this embodiment can be configured so that the area occupied by the groove 3 functioning as a mold lock on the lead frame 100 is narrow.

[0022] The groove portion 3 can also be formed in the lead terminal 1 as long as it is within the range of the resin sealing portion 5 that is sealed with the molding resin of the lead frame 100. In this case, a position where the formation of the thin portion 6 does not cause any problems is selected.

[0023] (Embodiment 2) Next, another embodiment (embodiment 2) of the lead frame according to one aspect of the present invention will be described. FIG. 3 is an explanatory diagram of embodiment 2 of the lead frame according to the present invention. As shown in FIG. 3, the lead frame 100A of this embodiment is configured such that a plurality of lead terminals 1 and a header portion 2 are connected by a connecting portion (not shown), and the header portion 2 is provided with a groove portion 3A that functions as a mold lock. 4 is a die pad portion of the header portion 2, 5 is a resin sealing portion in which a mold resin that seals the lead terminals 1 and the semiconductor element placed on the die pad portion 4 is formed when a semiconductor device is formed using the lead frame 100A of this embodiment, and 6 is a thin portion in a shape in which a part of the lead frame 100A is cut out. FIG. 4 is a schematic cross-sectional view of the groove portion 3A taken along the line BB of the lead frame 100A of FIG. 3.

[0024] As shown in FIGS. 3 and 4, the groove 3A has an opening on the upper surface (one surface) of the lead frame 100A, and the shape of the opening at the upper surface has a pair of opposing long sides and a pair of opposing short sides. The groove 3A is configured to have a protruding portion 32 that protrudes toward the wall 31B side where the wall 31A shown in FIG. 4 is disposed opposite to the wall 31B, and toward the wall 31A side where the wall 31B is disposed opposite to the wall 31B. As shown in FIG. 3, the walls disposed at positions perpendicular to the walls 31A and 31B also protrude toward the wall sides where they are disposed opposite to each other, and are configured to have a protruding portion corresponding to the protruding portion 32 shown in FIG. 4. The wall 31A and the like are configured to have an overhang portion 33 that has a reverse tapered shape in the depth direction of the groove 3A. These protruding portions and the overhang portion 33 can be formed, for example, by manufacturing the lead frame according to a manufacturing method of the lead frame described later.

[0025] As shown in Figures 3 and 4, when the lead frame 100A of this embodiment is used as a lead frame for a semiconductor device and a resin portion is formed from molded resin, the groove portion 3A having the overhang portion 33 fills the molded resin so that it reaches the overhang portion 33, and functions as a mold lock that enhances adhesion between the molded resin and the die pad portion 4 (lead frame) through an anchor effect.

[0026] Furthermore, lead frame 100A of this embodiment is configured to have thin portion 6 in which a part of the lower surface (the other surface) opposing the upper surface is cut out by forming groove portion 3A according to a lead frame manufacturing method described later. Furthermore, wall portions 31A, 31B, etc., equipped with protrusions 32, are positioned within thin portion 6. As with a normal lead frame, thin portion 6 can increase the adhesion between the molded resin and die pad portion 4 by the anchor effect.

[0027] In this manner, the groove 3A functioning as a mold lock of the lead frame 100A of this embodiment is composed of only one recess. If the width W2 shown in Fig. 4 is equivalent to the opening width of the recess 7a described in Fig. 11, the width W2 is about 0.10 mm, and the lead frame 100A of this embodiment can also be configured so that the area occupied by the groove 3A functioning as a mold lock on the lead frame 100A is small.

[0028] The groove portion 3A can be formed in the lead terminal 1 as long as it is within the range of the resin sealing portion 5 that is sealed with the molding resin of the lead frame 100A. In this case, a position where the formation of the thin portion 6 does not cause any problems is selected.

[0029] (Embodiment 3) Next, an embodiment (Embodiment 3) of a semiconductor device according to another aspect of the present invention will be described. Fig. 5 is an explanatory diagram of an embodiment of the semiconductor device according to the present invention. The semiconductor device 20 of this embodiment has a structure in which a semiconductor element 10 is mounted on the die pad portion 4 of the lead frame 100A shown in Figs. 3 and 4 described in the above-mentioned embodiment 2, the electrodes of the semiconductor element 10 and the lead terminals 1 are connected by metal wires 11, and the semiconductor element 10 is sealed with a molded resin to form a resin portion 51. As described in Fig. 4 above, the groove portion 3A has an overhang portion 33 having a reverse tapered shape in the depth direction of the groove portion 3A.

[0030] 5, in the semiconductor device 20 of this embodiment, the resin portion 51 is formed by the mold resin, and the mold resin is filled into the groove portion 3A so as to reach the overhang portion 33, so that the groove portion 3A functions as a mold lock that enhances the adhesion between the resin portion 51 (molded resin) and the die pad portion 4 (lead frame) by an anchor effect. As with a normal lead frame, the thin portion 6 also enhances the adhesion between the resin portion 51 and the die pad portion 4 by an anchor effect.

[0031] The semiconductor device of this embodiment can also be configured to include the lead frame 100 shown in FIGS. 1 and 2 and described in the first embodiment above, instead of the lead frame 100A.

[0032] Thus, the semiconductor device 20 of this embodiment includes a lead frame 100A equivalent to a lead frame having a thin portion used in a normal semiconductor device, and the lead frame 100A is configured such that the groove portion 3A is located in the thin portion 6. When the semiconductor element 10 is placed on the die pad portion 4 while avoiding the groove portion 3A, the semiconductor device 20 of this embodiment can mount a semiconductor element 10 of a size that reaches beyond the die pad portion 4 and onto the thin portion 6. This indicates that a semiconductor element 10 of a larger area can be mounted compared to the case where the mold lock formed by the recesses 7a and 7b described in Figs. 11 to 14 is placed on the die pad portion while avoiding the position of the thin portion. In other words, when a semiconductor element of a predetermined area is to be mounted, the semiconductor device 20 of this embodiment having a die pad portion 4 of a smaller area than the conventional one can be used. As a result, the semiconductor device can be miniaturized.

[0033] (Embodiment 1) Next, an embodiment (embodiment 1) of the manufacturing method of the lead frame, which is yet another aspect of the present invention, will be described. FIGS. 6 to 8 are explanatory diagrams of embodiment 1 of the manufacturing method of the lead frame of the present invention, and are explanatory diagrams of a method of forming a groove. The manufacturing method of the lead frame of this embodiment will be described with respect to a manufacturing method of the lead frame 100 described in embodiment 1 above. First, as shown in FIG. 6, a lead frame 100 in which a plurality of lead terminals 1 and a header part 2 are connected by a connecting part not shown is prepared. The lead frame 100 can be made of a metal plate of a uniform thickness selected from copper or a copper alloy, for example. Next, a recess 7 having a rectangular opening is formed at a position where a groove part is formed on the upper surface (one surface) of the lead frame 100, which is a resin sealing part 5 that is a part where a mold resin is formed to seal a semiconductor element placed on the die pad part 4 of the lead terminals 1 and the header part 2 when a semiconductor device is formed. 11, recess 7 is formed by placing a metal plate on the lower surface of lead frame 100, pressing lead frame 100 from the upper surface of lead frame 100 with a die, and deforming lead frame 100 into a recessed shape to a depth of about 1 / 4 to 1 / 2 the thickness of lead frame 100. Reference numeral 61 denotes an area where a thin portion is to be formed. FIG. 7 is a schematic cross-sectional view of recess 7 taken along line CC in FIG.

[0034] Next, as shown in Fig. 8, a metal flat plate 8 is placed on the upper surface of the lead frame 100 shown in Fig. 7, and the lead frame 100 is pressed upward (in the direction of the arrow) from the lower surface (the other surface) of the lead frame 100 with a die 9A. Here, the die 9A is shaped to press the region 61 in Fig. 6 in which the thin portion is to be formed. The region 61 in which the thin portion is to be formed is placed so as to overlap a part including the long side of the recess 7, so as to include the position where a part of the wall surface of the recess 7 is projected onto the lower surface of the lead frame 100. When the lower surface of the lead frame 100 is pressed, the lower surface of the lead frame 100 is deformed and becomes a shape in which a part is cut out, forming the thin portion 6 shown in Fig. 1.

[0035] When the bottom surface of the lead frame 100 is deformed to form the thin portion 6, the recess 7 is deformed at the same time. This deformation of the recess 7 occurs in the portion pressed by the mold 9A. In the example shown in Fig. 6, deformation occurs in a wall portion 71 that overlaps the recess 7 and the thin portion formed in the region 61 where the thin portion is to be formed. The wall portion 71 of the recess 7 deforms toward the left in Fig. 8 (the direction of the arrow), and the intermediate portion in the height direction of the wall portion 71 of the recess 7 is significantly deformed.

[0036] As a result, the recess 7 forms the groove 3 having the shape shown in Figs. 1 and 2. The wall 71 of the recess 7 shown in Fig. 8 becomes the deformed wall 31A shown in Fig. 2, and the groove 3 has a protruding portion 32 protruding toward the wall 31 opposite to which the wall 31A is disposed. The wall 31A has an overhanging portion 33 having a reverse taper shape in the depth direction of the groove 3. The groove 3 is disposed at a position where the wall 31A is located within the thin portion 6. Note that when the lower surface of the lead frame 100 is pressed, a part of the short side of the recess 7 is also deformed, but the change is slight and will not be described. The end of the thin portion 6 may also be deformed, but will not be described.

[0037] When the lead frame 100 manufactured by this embodiment is used as a lead frame for a semiconductor device and a resin portion is formed from molded resin, the groove portion 3 formed as described above functions as a mold lock that enhances adhesion between the molded resin and the die pad portion 4 (lead frame) through an anchor effect by filling the molded resin so that it reaches the overhang portion 33.

[0038] In the manufacturing method of the lead frame of this embodiment, after forming the recess 7 that can be formed by a mold, the groove 3 and the thin portion 6 can be formed by pressing the region 61 in which the thin portion is to be formed with the mold 9A, and the lead frame 100 can be formed inexpensively with high mass productivity. In addition, it is possible to configure the area occupied by the groove 3 on the lead frame 100 to be small. A part of the groove 3 is disposed at a position overlapping with the thin portion 6, and it is possible to configure a configuration with fewer restrictions on the position where the groove 3 can be formed.

[0039] (Embodiment 2) Next, another embodiment (embodiment 2) of the method for producing a lead frame, which is yet another aspect of the present invention, will be described. Figures 9 and 10 are explanatory diagrams of embodiment 2 of the method for producing a lead frame of the present invention, and are explanatory diagrams of a method for forming a groove. As the method for producing a lead frame of this embodiment, a method for producing the lead frame 100A described in embodiment 2 above will be described. First, as shown in Figure 9, a lead frame 100A is prepared in which a plurality of lead terminals 1 and a header portion 2 are connected by a connecting portion not shown. The lead frame 100A can be made of a metal plate of uniform thickness selected from copper or a copper alloy, for example. Next, a recess 7A having a rectangular opening is formed at a position where a groove portion is formed on the upper surface (one surface) of the lead frame 100A, which is a resin sealing portion 5 that is a portion where a mold resin is formed to seal a semiconductor element placed on the die pad portion 4 of the lead terminal 1 and the header portion 2 when a semiconductor device is formed. The recess 7A is formed by disposing a metal plate on the lower surface of the lead frame 100A, pressing the lead frame 100A from the upper surface of the lead frame 100A with a die, and deforming the lead frame 100A to a depth of about 1 / 4 to 1 / 2 the thickness of the lead frame 100A, as in the method described in FIG. 11. Reference numeral 61 denotes an area where a thin portion is to be formed. FIG. 10 is a schematic cross-sectional view of the recess 7A taken along the line DD in FIG.

[0040] Next, as shown in Fig. 10, a metal plate 8 is placed on the upper surface of the leadframe 100A, and the leadframe 100A is pressed upward (in the direction of the arrow) from the lower surface (the other surface) of the leadframe 100A with a die 9A. Here, the die 9A is shaped to press the thin portion formation planned region 61 shown in Fig. 9. The thin portion formation planned region 61 is placed overlapping the recess 7A so as to include the positions where all the walls of the recess 7A are projected onto the lower surface of the leadframe 100A. When the lower surface of the leadframe 100A is pressed, the lower surface of the leadframe 100A is deformed and becomes partially cut out, forming the thin portion 6 shown in Fig. 3.

[0041] When the lower surface of the lead frame 100A is deformed to form the thin portion 6, the recess 7A is deformed at the same time. This deformation of the recess 7A occurs in the portion pressed by the mold 9A. In the example shown in FIG. 10, deformation occurs in all of the walls of the recess 7A located within the thin portion 6 formed in the recess 7A and the thin portion-to-be-formed region 61. The walls 71A and 71B of the recess 7A shown in FIG. 10 are deformed toward the left and right directions (respectively the directions of the arrows) in FIG. 10, respectively, and all of the four walls of the recess 7A, including the wall portion not shown, are deformed. In this deformation, the middle portion in the height direction of the wall of the recess 7A is largely deformed.

[0042] As a result, the groove 3A having the shape shown in Figs. 3 and 4 is formed from the recess 7A. The wall 71A of the recess 7A shown in Fig. 10 becomes the deformed wall 31A shown in Fig. 4, and the wall 71B becomes the deformed wall 31B shown in Fig. 4. The wall 31A is disposed at a position perpendicular to the wall 31B and the wall 31B is disposed at a position opposite the wall 31B. The wall 31A and the wall 31B are also disposed at a position perpendicular to the wall 31A and the wall 31B. The wall 31A and the wall 31B have an overhang 33 having a reverse taper shape in the depth direction of the groove 3A. The groove 3A is disposed at a position where the wall 31A and the wall 31B are disposed within the thin portion 6. The end of the thin portion 6 may also be deformed, but the description will be given assuming that there is no deformation.

[0043] When the lead frame 100A manufactured by this embodiment is used as a lead frame for a semiconductor device and a resin portion is formed from molding resin, the groove portion 3A formed as described above functions as a mold lock that enhances adhesion between the molding resin and the die pad portion 4 (lead frame) through an anchor effect by filling the molding resin so that it reaches the overhang portion 33.

[0044] In the manufacturing method of the lead frame of this embodiment, after forming a recess 7A that can be formed by a mold, the groove 3A and the thin portion 6 are formed by pressing the region 61 in which the thin portion is to be formed with a mold 9A, and the lead frame 100A can be formed inexpensively with high mass productivity. In addition, it is possible to reduce the area occupied by the groove 3A on the lead frame 100A. In addition, since there are few restrictions on the position in which the groove 3A can be formed, the groove 3A can be arranged at a position overlapping the thin portion 6, and it is possible to configure the structure without narrowing the region in which the semiconductor element is placed.

[0045] Although the present invention has been described above, the present invention is not limited to the above-mentioned embodiment and implementation. For example, the groove 3 and the like may be formed in the lead terminal. The shape of the groove 3 and the like and the shape of the recess 7 for forming it are not limited to the rectangular shape shown in the figure. The material constituting the lead frame is not limited to copper or copper alloy, and can be appropriately selected from materials used as general lead frames, but it is particularly preferable to select copper or copper alloy, since this makes it easier to form the thin part and the protrusion.

[0046] (summary) (1) One embodiment of a lead frame which is one aspect of the present invention is a lead frame on which a semiconductor element is mounted and which is sealed with molded resin, the lead frame comprising: a groove portion disposed on one surface of the lead frame which is located at a resin sealing portion sealed with molded resin; and a thin portion having a shape in which a portion of the other surface facing the one surface of the lead frame which is located at the resin sealing portion is cut out, the wall portions of the groove portion being partly or entirely located within the thin portion, and the wall portions of the groove portion being partly or entirely located within the thin portion and comprising a protrusion which protrudes toward the opposing wall portion and has an overhang portion at a portion of the depth direction of the groove portion.

[0047] According to the lead frame of (1) above, the groove portion functioning as the mold lock is formed of a single recess, so that the area occupied by the mold lock on the lead frame can be made small.

[0048] (2) One embodiment of a method for manufacturing a lead frame, which is another aspect of the present invention, is a method for manufacturing a lead frame on which a semiconductor element is mounted and sealed with mold resin, comprising: a recess forming step of forming a recess in one surface of the lead frame located at a resin sealing portion sealed with mold resin; and a pressing step of pressing the other surface opposite to the one surface of the lead frame located at the resin sealing portion to form a thin portion and a groove portion, wherein the pressing step is configured to press a part of the lead frame including a position where some or all of the walls of the recess are projected onto the other surface of the lead frame, thereby forming a thin portion having a shape in which a part of the lead frame is cut out, and the some or all of the walls of the recess located within the thin portion protrude toward the opposing wall portions, respectively, and a part of the recess in the depth direction forms an overhanging shape, thereby forming the groove portion.

[0049] According to the above-mentioned method for manufacturing a lead frame (2), the thin portion and the groove portion are formed by the pressing process, so that the lead frame is formed such that some of the walls of the groove portion are located within the thin portion, or all of the walls of the groove portion are located within the thin portion. This means that there are fewer restrictions on the positions where the groove portion can be formed, and the lead frame can be manufactured easily.

[0050] (3) According to another embodiment, in the lead frame manufacturing method of (2) above, the pressing step is configured to be a step of pressing the lead frame from the other surface of the lead frame with a die having a protrusion corresponding to the thin portion.

[0051] According to the above-mentioned method (3) for producing a lead frame, the thin portion and the groove portion are formed using a mold, so that the lead frame can be produced inexpensively with high mass productivity.

[0052] (4) According to another embodiment, in the method for producing a lead frame according to (2) or (3) above, the lead frame is made of copper or a copper alloy.

[0053] According to the method for producing a lead frame described above in (4), the lead frame can be easily processed and the thin portion and the groove can be formed.

[0054] (5) One embodiment of a semiconductor device which is yet another aspect of the present invention comprises a lead frame, a semiconductor element mounted on the lead frame, and a resin portion in which the lead frame and the semiconductor element are sealed with mold resin, the lead frame comprising a groove portion disposed on one surface of the lead frame located at the resin sealing portion sealed with the mold resin, and a thin portion having a shape in which a portion of the other surface facing the one surface of the lead frame located at the resin sealing portion is cut out, some or all of the walls of the groove portion are located within the thin portion, and some or all of the walls located within the thin portion have a protruding portion that protrudes toward the opposing wall portion and has an overhang portion at a portion of the depth direction of the groove portion, the semiconductor element is mounted on the one surface of the lead frame which constitutes a die pad portion, and the mold resin is filled in the groove portion so as to reach the overhang portion.

[0055] According to the semiconductor device of (5) above, the area occupied by the groove portion on the lead frame that functions as a mold lock is small, and there are few restrictions on the location where the groove portion can be formed, so that the semiconductor device can be made smaller. [Explanation of symbols]

[0056] 100, 100A, 100a, 100b leadframe 1 Lead terminal 2 Header section 3, 3A groove 4 Die pad section 5 Resin sealing part 6 Thin section 7, 7A, 7a, 7b Recess 8 Metal flat plate 9A, 9a, 9b mold 10 Semiconductor elements 11 Metal Wire 20 Semiconductor Devices 31, 31A, 31B wall section 32 Protrusion 33 Overhang 51 Resin part 61 Thin-walled area 71, 71A, 71B wall section 72 Sloped wall

Claims

1. A lead frame on which a semiconductor element is mounted and sealed with a molding resin, a groove portion disposed on one surface of the lead frame located at a resin sealing portion sealed with a molding resin; a thin portion having a shape in which a part of a surface of the lead frame opposite to the surface of the lead frame located in the resin sealing portion is cut out; Equipped with A part or all of the walls of the groove are located within the thin-walled portion, A part or all of the walls located within the thin wall portion are provided with a protruding portion that protrudes toward the opposing wall portion and has an overhang portion in a part of the depth direction of the groove portion. Lead frame.

2. A method for manufacturing a lead frame on which a semiconductor element is mounted and sealed with a molding resin, comprising the steps of: a recess forming step of forming a recess on one surface of the lead frame located at a resin sealing portion that is sealed with a mold resin; a pressing process for pressing the other surface of the lead frame that faces the one surface located in the resin sealing portion to form a thin portion and a groove portion; Including, The pressing step includes: By pressing a part of the lead frame including a position where a part or all of the wall parts of the recess are projected onto the other surface of the lead frame, A thin portion is formed by cutting out a part of the lead frame, The groove is formed by the wall of the recess located in the thin portion protruding toward the opposing wall and forming an overhang shape at a portion of the recess in the depth direction. It is a process A method for manufacturing a lead frame.

3. the pressing step is a step of pressing the lead frame from the other surface of the lead frame with a die having a protrusion corresponding to the thin portion, The method for manufacturing the lead frame according to claim 2.

4. The lead frame is made of copper or a copper alloy. The method for manufacturing a lead frame according to claim 2 or 3.

5. a lead frame, a semiconductor element mounted on the lead frame, and a resin portion in which the lead frame and the semiconductor element are sealed with a molding resin; Equipped with The lead frame is a groove portion disposed on one surface of the lead frame located at a resin sealing portion sealed with the molding resin; a thin portion having a shape in which a part of a surface of the lead frame opposite to the surface of the lead frame located in the resin sealing portion is cut out; Equipped with A part or all of the walls of the groove are located within the thin-walled portion, A part or all of the wall portions located within the thin portion include a protruding portion that protrudes toward the opposing wall portion and has an overhang portion in a part of the depth direction of the groove portion, the semiconductor element is mounted on the one surface of the lead frame that constitutes a die pad portion, The molding resin is filled into the groove so as to reach the overhang portion. Semiconductor device.

Images