JP2023174472A - Lead frame and method for manufacturing the same - Google Patents

Abstract

To provide a lead frame having a resin part which can suppress peeling between a lead part and a resin part, and a method for manufacturing the same.SOLUTION: A lead frame 10 includes a die pad 11, a lead part 12 arranged around the die pad 11, and a resin part 18 arranged around the die pad 11 and the lead part 12. The lead part 12 has an internal terminal 51 positioned on the die pad 11 side, an external terminal 53 positioned opposite to the die pad 11, and a connection part 52 positioned between the internal terminal 51 and the external terminal 53. The internal terminal 51 is thinned from the rear face side, the external terminal 53 is thinned from the surface side, and the connection part 52 is thinned from both the surface side and the rear face side.SELECTED DRAWING: Figure 2

Description

The present disclosure relates to a lead frame and a method of manufacturing the same.

In recent years, there has been a demand for smaller and thinner semiconductor devices mounted on substrates. In order to meet such demands, various so-called QFN (Quad Flat Non-lead) type semiconductor devices have been proposed. A QFN type semiconductor device is constructed by sealing a semiconductor element mounted on a mounting surface of a lead frame with a sealing resin and exposing a portion of the leads on the back surface side.

Furthermore, in recent years, there has been a demand for increasing the number of leads (number of pins) without changing the chip size. In response to this, conventional methods have been to reduce the width of the leads. However, as the lead becomes thinner, the lead becomes more likely to deform, causing a problem in that it becomes difficult to perform wire bonding stably.

JP2019-57590A

Patent Document 1 discloses a technique in which a resin portion is provided on the back surface of a lead frame and then an unnecessary portion of the resin portion is removed. Generally, when force is applied to a lead part during wire bonding, a repulsive force is generated in the lead part. If this repulsive force is large, there is a risk that the lead part and the resin part will separate.

The present disclosure provides a lead frame and a method for manufacturing the same that can suppress separation of the lead part and the resin part in a lead frame having a resin part.

Embodiments of the present disclosure relate to [1] to [10] below.

[1] A lead frame including a die pad, a lead part arranged around the die pad, and a resin part arranged around the die pad and the lead part, and the lead part is arranged on the die pad side. an internal terminal located on the opposite side of the die pad, an external terminal located on the opposite side of the die pad, and a connecting portion located between the internal terminal and the external terminal, the internal terminal being thinned from the back side, In the lead frame, the external terminal is thinned from the front side, and the connection part is thinned from both the front side and the back side.

[2] The lead frame according to [1], wherein the resin part is located on the back side of the internal terminal and the connection part.

[3] The surface of the portion of the resin portion located between the lead portion and the die pad is located on the same plane as the back surface of the internal terminal and the back surface of the connection portion. Lead frame.

[4] The lead frame according to [1], wherein the resin portion is located on the surface side of the connection portion and the external terminal.

[5] The back surface of the portion of the resin portion located between the lead portion and the die pad is located on the same plane as the back surface of the internal terminal and the back surface of the connection portion. Lead frame.

[6] The lead frame according to any one of [1] to [5], wherein the die pad has a stepped portion located on the back surface side, and the stepped portion is in close contact with the resin portion.

[7] The lead frame according to any one of [1] to [6], wherein the thickness of the connecting portion is 10% or more and 45% or less of the maximum thickness of the lead frame.

[8] The lead according to any one of [1] to [7], wherein a metal layer is inserted between the die pad and the resin part or between the lead part and the resin part. flame.

[9] In the method for manufacturing a lead frame, a step of preparing a metal substrate, a step of etching the metal substrate from the back side of the metal substrate to the middle of the thickness direction to form a back side recess, and The die pad and the die pad are formed by forming a resin part on the back side of the substrate, covering the back side recess with the resin part, and etching the metal substrate from the front side of the metal substrate to the middle of the thickness direction. and a step of polishing the resin part by a predetermined thickness, wherein the lead part is arranged around an internal terminal located on the die pad side and a lead part located on the opposite side of the die pad. an external terminal located on the side, and a connection part located between the internal terminal and the external terminal, and in the step of etching from the surface side of the metal substrate, there is a connection part located between the die pad and the lead part. A method for manufacturing a lead frame, in which the resin portion located on the lead frame is exposed on the front surface side, and the external terminal and the connection portion are thinned from the front surface side.

[10] In the method for manufacturing a lead frame, a step of preparing a metal substrate, a step of etching the metal substrate from the surface side of the metal substrate to the middle of the thickness direction to form a surface side recess, and etching the metal substrate forming a resin part on the front side of the substrate and covering the front side recess with the resin part; polishing the resin part by a predetermined thickness; and polishing the metal substrate from the back side of the metal substrate in the thickness direction. forming a die pad and a lead part disposed around the die pad by etching halfway through the die pad, and the lead part includes an internal terminal located on the die pad side and an inner terminal located on the opposite side of the die pad. an external terminal located on the side, and a connection part located between the internal terminal and the external terminal, and in the step of etching from the back side of the metal substrate, there is a connection part between the die pad and the lead part. A method for manufacturing a lead frame, in which the resin portion located on the lead frame is exposed on the back side, and the internal terminals and the connecting portions are thinned from the back side.

According to the present disclosure, in a lead frame having a resin portion, separation of the lead portion and the resin portion can be suppressed.

FIG. 1 is a plan view showing a lead frame according to a first embodiment. FIG. 2 is a cross-sectional view (cross-sectional view taken along the line II--II in FIG. 1) showing the lead frame according to the first embodiment. FIG. 3 is a plan view showing the semiconductor device according to the first embodiment. FIG. 4 is a cross-sectional view (cross-sectional view taken along the line IV--IV in FIG. 3) showing the semiconductor device according to the first embodiment. 5(a)-(i) are cross-sectional views showing a method for manufacturing a lead frame according to the first embodiment. FIGS. 6A to 6E are cross-sectional views showing a method of manufacturing a semiconductor device according to the first embodiment. FIG. 7 is a sectional view showing a lead frame according to the second embodiment. FIG. 8 is a cross-sectional view showing a semiconductor device according to the second embodiment. 9(a)-(i) are cross-sectional views showing a method for manufacturing a lead frame according to the second embodiment. FIG. 10 is a sectional view showing a lead frame according to the third embodiment. FIGS. 11(a) and 11(b) are partially enlarged sectional views showing a lead frame according to a third embodiment. FIGS. 12A to 12D are cross-sectional views showing a method for manufacturing a lead frame according to the third embodiment. FIG. 13 is a sectional view showing a lead frame according to the fourth embodiment. FIGS. 14(a) and 14(b) are partially enlarged sectional views showing a lead frame according to a fourth embodiment. FIGS. 15(a) to 15(d) are cross-sectional views showing a method for manufacturing a lead frame according to the fourth embodiment.

(First embodiment)
The first embodiment will be described below with reference to FIGS. 1 to 6. In each of the following figures, the same parts are given the same reference numerals, and some detailed explanations may be omitted.

In this specification, the X direction and the Y direction are two directions parallel to each side of the lead frame 10 or the package area 10a, and the X direction and the Y direction are orthogonal to each other. Further, the Z direction is a direction perpendicular to both the X direction and the Y direction. Moreover, "inside" and "inner side" refer to the side facing toward the center of each package area 10a. "Outside" and "outside" refer to the side away from the center of each package area 10a. Furthermore, the term "surface" refers to a surface facing the opposite side (positive side in the Z direction) from the surface connected to an external wiring board (not shown). The "back surface" refers to the surface opposite to the "front surface" (negative side in the Z direction) and the surface connected to the wiring board.

Further, in this specification, half etching refers to etching the material to be etched halfway in the thickness direction thereof. The thickness of the material to be etched after half etching may be, for example, 10% or more and 90% or less, or 30% or more and 70% or less, or 40% or more and 60% or less of the thickness of the material to be etched before half etching.

(Lead frame configuration)
First, the outline of the lead frame according to this embodiment will be explained with reference to FIGS. 1 and 2. 1 and 2 are diagrams showing a lead frame according to this embodiment.

As shown in FIG. 1, the lead frame 10 includes a package area (unit lead frame) 10a. A plurality of package regions 10a are arranged in multiple rows and stages (in a matrix) in a plan view within the lead frame 10. Note that the present invention is not limited to this, and it is sufficient that one or more package areas 10a exist. Note that the package regions 10a are regions corresponding to semiconductor devices 20 (described later), and are regions located inside the imaginary line in FIG. 1. Further, the virtual line in FIG. 1 corresponds to the outer periphery of the semiconductor device 20.

Next, the structure of the lead frame 10 will be further described with reference to FIGS. 1 and 2.

As shown in FIG. 1, the lead frame 10 includes a die pad 11, a plurality of lead parts 12, and a resin part 18. Each of the plurality of lead parts 12 has an elongated shape and is provided around the die pad 11. Each lead portion 12 connects the semiconductor element 21 to an external wiring board (not shown). The resin part 18 is arranged around the die pad 11 and the lead part 12 on the back side of the lead frame 10. The plurality of package areas 10a are connected to each other via support leads (support members) 13. Support leads 13 support die pad 11 and lead portion 12 . The support leads 13 extend along the X direction and the Y direction, respectively.

Die pad 11 has a substantially square shape in plan view. In this case, at least the central portion of the die pad 11 is not half-etched and has the same thickness as the metal substrate before processing (metal substrate 31 to be described later). The planar shape of the die pad 11 is not limited to a square, but may be a polygon such as a rectangle. Furthermore, hanging leads 14 are connected to the four corners of the die pad 11. The die pad 11 is connected and supported by the support leads 13 via four suspension leads 14.

As shown in FIG. 2, the die pad 11 has a die pad surface 11a located on the front side and a die pad back surface 11b located on the back side. A semiconductor element 21, which will be described later, is mounted on the die pad surface 11a. The die pad back surface 11b is exposed outward from the lead frame 10.

On the side of the die pad 11 facing the lead portion 12, a die pad side surface 11c and a step portion 11d are formed. The die pad side surface 11c is located on the die pad surface 11a side and is exposed outward from the lead frame 10. The step portion 11d is located closer to the back surface than the die pad side surface 11c. The stepped portion 11d has a stepped top surface 11f and a stepped side surface 11g. The step top surface 11f is located on the same plane as the resin surface 18a of the resin portion 18. The step side surface 11g extends from the die pad back surface 11b toward the step top surface 11f. The step portion 11d is filled with a resin portion 18. The step top surface 11f and the step side surface 11g of the step portion 11d are in close contact with the resin portion 18, respectively. A die pad protrusion 11h is formed between the die pad side surface 11c and the step portion 11d. The die pad protrusion 11h protrudes toward the lead portion 12 side. The surface of the die pad protrusion 11h on the front side (die pad side surface 11c side) is curved toward the back side. The step side surface 11g is located inside the die pad side surface 11c (on the side farther from the lead portion 12). The stepped side surface 11g may be located at the same position as the die pad side surface 11c in plan view. Alternatively, the step side surface 11g may be located inside the die pad side surface 11c (on the side farther from the lead portion 12). The step side surface 11g may be located at the same position as the die pad protrusion 11h in plan view. Alternatively, the step side surface 11g may be located inside the die pad protrusion 11h (on the side farther from the lead portion 12).

Each lead portion 12 is connected to a semiconductor element 21 via a bonding wire 22, as will be described later. The lead portion 12 is arranged with a space interposed between the lead portion 12 and the die pad 11 . The lead portions 12 each extend from the support lead 13.

The plurality of lead parts 12 are arranged along the periphery of the die pad 11. External terminal surfaces 17 that are electrically connected to external wiring boards (not shown) are formed on the back surfaces of the lead portions 12, respectively. Each external terminal surface 17 is exposed to the outside from the semiconductor device 20 after the semiconductor device 20 (described later) is manufactured.

The lead portion 12 has an internal terminal 51, a connecting portion 52, and an external terminal 53. Internal terminal 51 is located on the inside (die pad 11 side). The external terminal 53 is located on the outside (on the opposite side of the die pad 11, on the support lead 13 side). The connecting portion 52 is located between the internal terminal 51 and the external terminal 53. The internal terminal 51 is located at the inner end of the lead portion 12, and an internal terminal surface 15 is formed on the front surface thereof. This internal terminal surface 15 is a region that is electrically connected to the semiconductor element 21 via a bonding wire 22 as described later. Note that a plating layer 25 is provided on the internal terminal surface 15 to improve adhesion to the bonding wire 22. The plating layer 25 may be made of silver plating, for example.

The internal terminal 51 is thinned from the back side by, for example, half etching. The internal terminal 51 is not thinned from the surface side. The internal terminal 51 has the above-described internal terminal surface 15 and an internal terminal back surface 51b. The internal terminal surface 15 is located on the surface side of the internal terminal 51. The internal terminal back surface 51b is located on the back surface side of the internal terminal 51. The inner terminal back surface 51b is in close contact with the resin portion 18. Furthermore, a lead side surface 51c is formed on the side of the internal terminal 51 facing the die pad 11. The lead side surface 51c is not covered with the resin portion 18 and is exposed to the outside. Further, a lead protrusion 51e is formed between the lead side surface 51c and the internal terminal back surface 51b. The lead protrusions 51e protrude toward the die pad 11 side. The front side (lead side surface 51c side) of the lead protrusion 51e is curved toward the back side. The back surface of the lead protrusion 51e is located on the same plane as the internal terminal back surface 51b. An internal terminal outer surface 51d is formed on the side of the internal terminal 51 opposite to the die pad 11 (support lead 13 side).

The connection portion 52 is thinned from both the front side and the back side by, for example, half etching. The connecting portion 52 is connected to the internal terminal 51 on the inside and to the external terminal 53 on the outside. The connecting portion 52 has a connecting portion surface 52a located on the front side and a connecting portion back surface 52b located on the back side. The connecting portion front surface 52a and the connecting portion back surface 52b are surfaces formed by etching, respectively. The connecting portion surface 52a is not covered with the resin portion 18 and is exposed to the outside. The connecting portion back surface 52b is in close contact with the resin portion 18. Further, the connecting portion surface 52a is located on the same plane as an external terminal surface 53a, which will be described later. The connecting portion back surface 52b is located on the same plane as the internal terminal back surface 51b.

The external terminal 53 is located on the support lead 13 side, and its outer end is connected to the support lead 13. The external terminal 53 is thinned from the surface side by, for example, half etching. The external terminal 53 is not thinned from the back side. The external terminal 53 has an external terminal surface 53a and the external terminal surface 17 described above. The external terminal surface 53a is located on the surface side of the external terminal 53 and is exposed to the outside. The external terminal surface 17 is located on the back side of the external terminal 53 and is exposed to the outside. Furthermore, an external terminal inner surface 53d is formed at a position on the back surface side of the external terminal 53 from the connection portion back surface 52b. The external terminal inner surface 53d extends from the external terminal surface 17 toward the connection portion back surface 52b. The resin portion 18 is in close contact with the inner surface 53d of the external terminal. Note that the area between the external terminal surface 17 and the support lead 13 may be made thinner from the back side.

The resin part 18 is arranged around the die pad 11 and the lead part 12. That is, as shown in FIG. 1, when viewed from the front side, the resin part 18 includes one side of the die pad 11, a plurality of lead parts 12 facing the side, a support lead 13, and two suspension leads 14. It is located in an area surrounded by Furthermore, when viewed from the back side, the resin portion 18 is surrounded by one side of the die pad 11, the external terminal surface 17 of the plurality of lead portions 12 facing the side, the support lead 13, and the two suspension leads 14. It is located in an area where In addition, in FIG. 1, the resin portion 18 is shown by hatching (the same applies to FIG. 3, which will be described later).

The resin portion 18 is arranged on the back side of the lead frame 10. That is, the resin portion 18 exists only on the back side (minus side in the Z direction) of the lead frame 10 from a midway position in the thickness direction. The resin portion 18 does not exist on the surface side (positive side in the Z direction) from a midway position in the thickness direction (Z direction). Note that the intermediate position is not limited to the center in the thickness direction of the lead frame 10, but may be located on the front side or the back side of the center in the thickness direction. In FIG. 2, an intermediate position in the thickness direction corresponds to a position where the internal terminal back surface 51b and the connecting portion back surface 52b are present in the thickness direction.

As shown in FIG. 2, the resin portion 18 is arranged within the stepped portion 11d of the die pad 11. As shown in FIG. Specifically, the resin portion 18 is arranged in a region surrounded by the step side surface 11g and the step top surface 11f. Further, the resin part 18 is arranged on the back side of the lead part 12. Specifically, the resin portion 18 is in close contact with the external terminal inner surface 53d of the lead portion 12, the connecting portion back surface 52b, and the internal terminal back surface 51b.

The resin portion 18 has a resin surface 18a located on the front side and a resin back surface 18b located on the back side. Of these, the resin surface 18a is exposed outward from the space between the die pad side surface 11c and the lead side surface 51c. Further, the resin surface 18a, the step top surface 11f, the internal terminal back surface 51b, and the connection portion back surface 52b are located on the same plane. The resin back surface 18b is exposed outward from the back surface side of the lead frame 10. The resin back surface 18b, the die pad back surface 11b, and the external terminal surface 17 are located on the same plane.

As the resin portion 18, thermosetting resin such as silicone resin or epoxy resin, or thermoplastic resin such as PPS resin may be used. Note that, in order to improve the adhesion between the resin part 18 and the sealing resin 23 described later, it is preferable to use the same material as the sealing resin 23 as the resin part 18.

The parts other than the resin part 18 of the lead frame 10 described above are entirely made of metal such as copper, copper alloy, and 42 alloy (Fe alloy with 42% Ni). Further, the maximum thickness T1 of the lead frame 10 may be 80 μm or more and 300 μm or less, although it depends on the configuration of the semiconductor device 20 to be manufactured. In this specification, the maximum thickness of the lead frame 10 is the thickness at the thickest part of the lead frame 10 (distance in the Z direction), and refers to the thickness at a part that is not thinned from the front side or the back side. . Further, the maximum thickness of the lead frame 10 corresponds to the thickness of a metal substrate 31, which will be described later. In this embodiment, since the resin part 18 is provided on the back side of the lead part 12, the lead part 12 is not easily deformed by the force applied during wire bonding. Thereby, the maximum thickness T1 of the lead frame 10 can be reduced.

The thickness T2 of the internal terminal 51 may be greater than or equal to 40% and less than or equal to 70% of the maximum thickness T1 of the lead frame 10, or may be greater than or equal to 50% and less than or equal to 60%. The thickness T2 of the internal terminal 51 may be greater than or equal to 32 μm and less than or equal to 210 μm, or may be greater than or equal to 35 μm and less than or equal to 180 μm.

The thickness T3 of the connecting portion 52 may be 10% or more and 45% or less of the maximum thickness T1 of the lead frame 10, or may be 15% or more and 30% or less. The thickness T3 of the connecting portion 52 may be 30 μm or more and 135 μm or less, or 35 μm or more and 75 μm or less. By setting the thickness T3 of the connecting portion 52 to 10% or more of the maximum thickness T1 of the lead frame 10, conductivity between the internal terminal 51 and the external terminal 53 can be ensured. By setting the thickness T3 of the connecting portion 52 to 45% or less of the maximum thickness T1 of the lead frame 10, the repulsive force of the connecting portion 52 against the force applied to the internal terminal surface 15 during wire bonding can be suppressed, as will be described later. Thereby, it is possible to suppress separation of the lead portion 12 and the resin portion 18 due to this repulsive force.

The thickness T4 of the external terminal 53 may be 40% or more and 70% or less of the maximum thickness T1 of the lead frame 10, or may be 50% or more and 60% or less. The thickness T4 of the external terminal 53 may be greater than or equal to 32 μm and less than or equal to 175 μm, or may be greater than or equal to 40 μm and less than or equal to 150 μm.

The thickness T5 of the resin portion 18 may be 30% or more and 60% or less of the maximum thickness T1 of the lead frame 10, or may be 40% or more and 50% or less. The thickness T5 of the resin portion 18 may be 24 μm or more and 150 μm or less, or 32 μm or more and 125 μm or less.

(Configuration of semiconductor device)
Next, the semiconductor device according to this embodiment will be explained with reference to FIGS. 3 and 4. 3 and 4 are diagrams showing a semiconductor device (QFN type) according to this embodiment.

As shown in FIGS. 3 and 4, the semiconductor device (semiconductor package) 20 includes a die pad 11, a plurality of lead parts 12, a semiconductor element 21, and a plurality of bonding wires (connection members) 22. The plurality of lead parts 12 are arranged around the die pad 11. The semiconductor element 21 is mounted on the die pad 11. Bonding wire 22 electrically connects lead portion 12 and semiconductor element 21 . Further, a resin portion 18 is arranged around the die pad 11 and the lead portion 12 and on the back side of the semiconductor device 20 . Further, the die pad 11 , the lead portion 12 , the semiconductor element 21 , and the bonding wire 22 are resin-sealed with a sealing resin 23 .

The die pad 11, lead portion 12, and resin portion 18 of the semiconductor device 20 are manufactured from the lead frame 10 described above. The configurations of the die pad 11, the lead portion 12, and the resin portion 18 are the same as those shown in FIGS. 1 and 2 described above, except for regions not included in the semiconductor device 20, so detailed description thereof will be omitted here.

As the semiconductor element 21, it is possible to use various semiconductor elements commonly used in the past. As the semiconductor element 21, for example, an integrated circuit, a large-scale integrated circuit, a transistor, a thyristor, a diode, etc. may be used. This semiconductor element 21 has a plurality of electrodes 21a to which bonding wires 22 are respectively attached. Further, the semiconductor element 21 is fixed to the surface of the die pad 11 with an adhesive 24. As the adhesive 24, for example, die bonding paste or the like may be used.

Each bonding wire 22 is made of a highly conductive material such as gold or copper. One end of each bonding wire 22 is connected to the electrode 21a of the semiconductor element 21, respectively. The other end of each bonding wire 22 is connected to a plating layer 25 located on the internal terminal surface 15 of each lead portion 12, respectively.

As the sealing resin 23, a thermosetting resin such as a silicone resin or an epoxy resin, or a thermoplastic resin such as a PPS resin may be used. The entire thickness of the sealing resin 23 may be about 300 μm or more and 1500 μm or less. Further, one side of the sealing resin 23 (one side of the semiconductor device 20) may be, for example, 0.2 mm or more and 16 mm or less. In the space between the die pad 11 and the lead portion 12, the sealing resin 23 is in close contact with the resin surface 18a of the resin portion 18. Further, the sealing resin 23 is in close contact with the connection portion surface 52a and the external terminal surface 53a of the lead portion 12. Note that in FIG. 3, illustration of the sealing resin 23 is omitted.

(Lead frame manufacturing method)
Next, a method for manufacturing the lead frame 10 shown in FIGS. 1 and 2 will be explained using FIGS. 5(a) to 5(i).

First, as shown in FIG. 5(a), a flat metal substrate 31 is prepared. As the metal substrate 31, a substrate made of metal such as copper, copper alloy, 42 alloy (Fe alloy with 42% Ni) may be used. Note that it is preferable to use a metal substrate 31 that has been subjected to degreasing and cleaning treatment on both surfaces.

Next, a photosensitive resist is applied to the entire front and back surfaces of the metal substrate 31, respectively, and dried. Subsequently, the photosensitive resist on the metal substrate 31 is exposed to light through a photomask and developed. As a result, etching resist layers 32 and 33 having desired openings 32b and 33b are formed (FIG. 5(b)).

Next, by half etching, the thickness of the metal substrate 31 is reduced from the back side of the metal substrate 31 to the middle of the thickness direction. In this case, the etching resist layer 33 on the back side is used as a corrosion-resistant film, and the back side of the metal substrate 31 is etched with an etchant (FIG. 5(c)). Note that at this time, the front surface side of the metal substrate 31 may be covered with a mask or the like (not shown). As a result, a back side recess 36, which is a non-penetrating recess, is formed on the back side of the metal substrate 31. This back side recessed portion 36 has a shape corresponding to the resin portion 18 . Note that the corrosive liquid can be appropriately selected depending on the material of the metal substrate 31 used. For example, when copper is used as the metal substrate 31, a ferric chloride aqueous solution may be used as the etchant. In this case, a ferric chloride aqueous solution may be spray-etched from one or both surfaces of the metal substrate 31.

Next, the etching resist layer 33 on the back side is peeled off and removed, leaving the etching resist layer 32 on the front side (FIG. 5(d)). Next, the metal substrate 31 is washed with water and dried.

Next, a resin part 18 is formed on the back side of the metal substrate 31, and the resin part 18 covers the back side recess 36 (FIG. 5(e)). At this time, a thermosetting resin or a thermoplastic resin may be injection molded or transfer molded on the back side of the metal substrate 31. As a result, the resin portion 18 is filled into the back side recess 36. Note that the thickness T6 of the resin portion 18 from the portion 11e corresponding to the die pad back surface 11b may be 25 μm or more and 200 μm or less.

Next, by half etching, the thickness of the metal substrate 31 is reduced from the front side of the metal substrate 31 to the middle in the thickness direction. In this case, the etching resist layer 32 on the front side is used as a corrosion-resistant film, and the front side of the metal substrate 31 is etched with an etchant (FIG. 5(f)). Note that the same etchant as that used when etching the back side of the metal substrate 31 may be used (FIG. 5(c)).

As a result, the front surface side of the metal substrate 31 is etched, and the outer shapes of the die pad 11, lead portions 12, and support leads 13 are formed. Further, a gap is formed between the die pad 11 and the lead portion 12, and the resin portion 18 is exposed on the front side. Further, the surface side of the connecting portion 52 of the lead portion 12 is thinned by etching to such an extent that the resin portion 18 is not exposed. Similarly, the surface side of the external terminal 53 of the lead portion 12 is thinned by etching. When etching the surface side of the metal substrate 31, for example, the surface of the connection portion 52 and the surface of the external terminal 53 may be covered with a resist (not shown). In this case, after the etching between the die pad 11 and the lead portion 12 has progressed to a certain extent, the resist is removed. Thereafter, the surface of the connecting portion 52 and the surface of the external terminal 53 may be thinned by etching (two-step etching). Alternatively, the surface side of the metal substrate 31 may be thinned by only one step of etching.

Next, the resin portion 18 is polished to a predetermined thickness (FIG. 5(g)). Specifically, the resin portion 18 is polished from the back side, and after the metal portion constituting the metal substrate 31 appears, the polishing of the resin portion 18 is finished. As a result, the die pad back surface 11b of the die pad 11 and the external terminal surface 17 of the lead portion 12 are exposed to the back surface side. Note that, as a method of polishing the resin portion 18, for example, buffing can be used.

In this embodiment, the step of exposing the resin portion 18 to the surface side by etching (FIG. 5(f)) is performed before the step of polishing the resin portion 18 (FIG. 5(g)). Thereby, when etching the front side of the metal substrate 31, the back side of the metal substrate 31 is covered with the resin portion 18. Therefore, only the front side of the metal substrate 31 can be made thinner without providing a separate step of covering the back side of the metal substrate 31 with another member. Note that the step of polishing the resin portion 18 (FIG. 5(g)) may be performed before the step of etching the front surface side of the metal substrate 31 (FIG. 5(f)).

Next, the etching resist layer 32 on the front surface side is peeled off and removed (FIG. 5(h)). Next, the metal substrate 31 is washed with water and dried.

Thereafter, electrolytic plating is applied to the internal terminals 51 of the lead portion 12. As a result, metal (for example, silver) is deposited on the internal terminals 51 of the lead portion 12 to form the plating layer 25. In this way, the lead frame 10 shown in FIGS. 1 and 2 is obtained (FIG. 5(i)).

(Method for manufacturing semiconductor devices)
Next, a method for manufacturing the semiconductor device 20 shown in FIGS. 3 and 4 will be described using FIGS. 6(a) to 6(e).

First, the lead frame 10 is manufactured, for example, by the method shown in FIGS. 5(a) to 5(i) (FIG. 6(a)).

Next, the semiconductor element 21 is mounted on the die pad 11 of the lead frame 10. In this case, the semiconductor element 21 is placed and fixed on the die pad 11 using the adhesive 24 (die attach step) (FIG. 6(b)). As the adhesive 24, for example, die bonding paste or the like may be used.

Next, each electrode 21a of the semiconductor element 21 and the plating layer 25 formed on each lead part 12 are electrically connected to each other by bonding wires (connecting members) 22 (wire bonding process) (FIG. 6( c)). At this time, each electrode 21a of the semiconductor element 21 and the internal terminal 51 of each lead part 12 are connected by the bonding wire 22 while applying ultrasonic waves through the capillary 38 of the wire bonding device.

Next, a sealing resin 23 is formed on the lead frame 10 by, for example, injection molding or transfer molding a thermosetting resin or a thermoplastic resin (FIG. 6(d)). In this way, the die pad 11, lead portion 12, semiconductor element 21, and bonding wire 22 are sealed.

Next, the sealing resin 23 and support leads 13 between each semiconductor element 21 are diced. Thereby, the lead frame 10 is separated into each semiconductor device 20. At this time, for example, the sealing resin 23 and support leads 13 between the semiconductor devices 20 may be cut while rotating a blade containing artificial diamond.

In this way, the semiconductor device 20 shown in FIGS. 3 and 4 is obtained (FIG. 6(e)).

By the way, in the wire bonding step (FIG. 6C) described above, when connecting the bonding wire 22 to the internal terminal 51 of each lead part 12, a pressing force F1 is applied to each lead part 12 by the capillary 38. In particular, a pressing force F1 is applied to the connecting portion 52 of the lead portion 12 from the front side toward the back side. Thereafter, when the pressing force F1 by the capillary 38 is released, a repulsive force F2 against the pressing force F1 is generated in the connecting portion 52 from the back side to the front side. If this repulsive force F2 is large, there is a risk that the resin portion 18 may peel off from the connecting portion back surface 52b.

In contrast, according to the present embodiment, the connecting portion 52 of the lead portion 12 is thinned from both the front side and the back side. That is, the connecting portion 52 is thin and flexible. Thereby, it is possible to reduce the repulsive force F2 generated in the connecting portion 52 when the pressing force F1 by the capillary 38 is released. As a result, peeling of the resin portion 18 from the connection portion back surface 52b can be suppressed.

Further, according to the present embodiment, the resin portion 18 is located on the back side of the internal terminal 51 and the connecting portion 52. That is, the resin portion 18 supports the lead portion 12 from the back side. Thereby, deformation of the lead portion 12 can be suppressed in the manufacturing process of the lead frame 10 and the manufacturing process of the semiconductor device 20. Therefore, the thickness of the lead portion 12 can be reduced, and the thickness of the entire lead frame 10 can also be reduced.

Further, according to the present embodiment, the resin surface 18a of the resin portion 18 located between the lead portion 12 and the die pad 11 is located on the same plane as the internal terminal back surface 51b and the connection portion back surface 52b. Thereby, the sealing resin 23 can be brought into close contact with the die pad side surface 11c and the lead side surface 51c, and separation of the die pad 11 and the lead portion 12 from the sealing resin 23 can be suppressed.

Further, according to the present embodiment, the die pad 11 has a stepped portion 11d located on the back side, and the stepped portion 11d is in close contact with the resin portion 18. This increases the adhesion between the die pad 11 and the resin portion 18. As a result, separation of the die pad 11 and the resin portion 18 can be suppressed.

Further, according to the present embodiment, the thickness T3 of the connecting portion 52 is 10% or more of the maximum thickness T1 of the lead frame 10. Thereby, conductivity between the internal terminal 51 and the external terminal 53 can be ensured. Further, the thickness T3 of the connecting portion 52 is 45% or less of the maximum thickness T1 of the lead frame 10. Thereby, in the wire bonding process, it is possible to reduce the repulsive force generated in the connecting portion 52 when the pressing force by the capillary 38 is released.

(Second embodiment)
Next, a second embodiment will be described with reference to FIGS. 7 to 9. 7 to 9 are diagrams showing the second embodiment. The second embodiment shown in FIGS. 7 to 9 differs mainly in that the resin portion 18 is located on the surface side of the connection portion 52 and the external terminal 53, and the other configuration is the same as that of the first embodiment described above. This is substantially the same as the embodiment. In FIGS. 7 to 9, the same parts as those in the first embodiment shown in FIGS. 1 to 6 are given the same reference numerals, and detailed explanations will be omitted.

(Configuration of lead frame and semiconductor device)
FIG. 7 is a sectional view showing a lead frame 10A according to this embodiment, and FIG. 8 is a sectional view showing a semiconductor device 20A according to this embodiment.

In the lead frame 10A shown in FIG. 7 and the semiconductor device 20A shown in FIG. 8, the resin portion 18 is located on the surface side of the connection portion 52 and the surface side of the external terminal 53.

As shown in FIG. 7, the resin portion 18 is arranged on the front surface side of the lead frame 10A. In other words, the resin portion 18 does not exist on the back side (positive side in the Z direction) of the lead frame 10A from a position halfway in the thickness direction (Z direction), but on the front side (minus side in the Z direction) from a position halfway in the thickness direction. side). Note that the intermediate position is not limited to the center in the thickness direction of the lead frame 10A, but may be located on the front side or back side of the center in the thickness direction. In FIG. 7, an intermediate position in the thickness direction corresponds to a position where the internal terminal back surface 51b and the connecting portion back surface 52b are present in the thickness direction.

As shown in FIG. 7, the resin portion 18 is arranged on the front surface side of the die pad 11. As shown in FIG. Specifically, the resin portion 18 is in close contact with the die pad side surface 11c of the die pad 11. Further, the resin portion 18 is in close contact with the surface side of the die pad protrusion 11h. Furthermore, the resin portion 18 is also in close contact with the lead side surface 51c of the lead portion 12 and the front surface side of the lead projection portion 51e.

The resin part 18 is arranged on the front surface side of the lead part 12. Specifically, the resin portion 18 is in close contact with the inner terminal outer surface 51d, the connecting portion surface 52a, and the outer terminal surface 53a of the lead portion 12. The resin surface 18a is exposed outward from the surface side of the lead frame 10A. The resin surface 18a, the die pad surface 11a, and the internal terminal surface 15 are located on the same plane. The resin back surface 18b is exposed outward from the back surface side of the lead frame 10A. Further, the resin back surface 18b, the internal terminal back surface 51b, and the connection portion back surface 52b are located on the same plane. Note that the resin back surface 18b of the resin portion 18, the die pad back surface 11b, and the external terminal surface 17 are not on the same plane, and the resin back surface 18b is located closer to the front surface than the die pad back surface 11b and the external terminal surface 17. .

In the semiconductor device 20A shown in FIG. 8, the resin surface 18a of the resin portion 18 is in close contact with the sealing resin 23. The resin back surface 18b of the resin portion 18 is exposed to the outside from the back surface side of the semiconductor device 20A. Note that the sealing resin 23 may wrap around the resin back surface 18b side of the resin portion 18.

In addition, the elements constituting the lead frame 10A and the semiconductor device 20A are substantially the same as those in the first embodiment.

(Lead frame manufacturing method)
Next, a method for manufacturing the lead frame 10A shown in FIG. 7 will be explained using FIGS. 9(a) to 9(i). In FIGS. 9(a)-(i), the same parts as in FIGS. 5(a)-(i) are given the same reference numerals, and detailed description thereof will be omitted.

First, a metal substrate 31 is prepared (FIG. 9(a)) in substantially the same manner as the steps shown in FIGS. (Fig. 9(b)).

Next, by half etching, the thickness of the metal substrate 31 is reduced from the front side of the metal substrate 31 to the middle in the thickness direction, thereby forming the front side recesses 37A and 37B (FIG. 9(c)). The front-side recesses 37A and 37B include a first front-side recess 37A corresponding to the space between the die pad 11 and the lead portion 12, and a second front-side recess 37B corresponding to the surfaces of the connection portion 52 and the external terminal 53. The depth of the first surface side recess 37A is deeper than the depth of the second surface side recess 37B. When etching the front side of the metal substrate 31, for example, a portion corresponding to the second front side recess 37B may be covered with a resist (not shown). In this case, the resist is removed after etching of the first surface side recess 37A has progressed to a certain extent. Thereafter, the second surface side recess 37B may be formed by etching. Alternatively, the surface side of the metal substrate 31 may be thinned by etching once.

Next, the etching resist layer 32 on the front side is peeled off (FIG. 9(d)).

Subsequently, the resin portion 18 is formed on the front surface side of the metal substrate 31 in substantially the same manner as the step shown in FIG. 5(e) described above (FIG. 9(e)). At this time, the resin portion 18 covers the front side recesses 37A and 37B.

Next, the resin portion 18 is polished to a predetermined thickness in substantially the same manner as the step shown in FIG. 5(g) described above (FIG. 9(f)). Specifically, the resin portion 18 is polished from the front side, and after the metal portion constituting the metal substrate 31 appears, the polishing of the resin portion 18 is finished.

Next, by half etching, the metal substrate 31 is thinned from the back side of the metal substrate 31 to the middle of the thickness direction using the etching resist layer 33 on the back side as a corrosion-resistant film (FIG. 9(g)). As a result, the outer shapes of the die pad 11, lead portions 12, and support leads 13 are formed. Further, by half-etching the back side of the metal substrate 31, the resin portion 18 is exposed from between the die pad 11 and the lead portion 12 on the back side. Further, the back surface side of the connecting portion 52 of the lead portion 12 is thinned by etching to such an extent that the resin portion 18 is not exposed. Similarly, the back side of the external terminal 53 of the lead portion 12 is thinned by etching.

Next, the etching resist layer 33 on the back side is peeled off and removed (FIG. 9(h)). Next, the metal substrate 31 is washed with water and dried.

Thereafter, the plating layer 25 is formed on the internal terminal 51 of the lead portion 12 in substantially the same manner as the step shown in FIG. 5(i) described above. In this way, the lead frame 10A shown in FIG. 7 is obtained (FIG. 5(i)).

Note that in this embodiment, the step of exposing the resin portion 18 to the back surface side by etching (FIG. 9(g)) is performed before the step of polishing the resin portion 18 (FIG. 9(f)). Also good.

(Method for manufacturing semiconductor devices)
The method for manufacturing the semiconductor device 20A according to this embodiment can be performed in substantially the same manner as the method for manufacturing the semiconductor device 20 shown in FIGS. 6(a) to 6(e).

According to this embodiment, the connecting portion 52 of the lead portion 12 is thinned from both the front side and the back side. That is, the connecting portion 52 is thin and flexible. Thereby, in the wire bonding process, it is possible to reduce the repulsive force generated in the connecting portion 52 when the force by the capillary 38 is released. As a result, peeling of the resin portion 18 from the connecting portion surface 52a can be suppressed.

Further, according to the present embodiment, the resin portion 18 is located on the surface side of the internal terminal 51 and the connecting portion 52. That is, the resin portion 18 supports the lead portion 12 from the front side. Thereby, deformation of the lead portion 12 can be suppressed in the manufacturing process of the lead frame 10A or the semiconductor device 20A. Therefore, the thickness of the lead portion 12 can be reduced, and the overall thickness of the lead frame 10A can be reduced.

(Third embodiment)
Next, a third embodiment will be described with reference to FIGS. 10 to 12. 10 to 12 are diagrams showing the third embodiment. In the third embodiment shown in FIGS. 10 to 12, metal layers 27a to 27d are mainly inserted between the die pad 11 and the resin part 18 or between the lead part 12 and the resin part 18. This is different in this point, and the other configurations are substantially the same as the first embodiment described above. In FIGS. 10 to 12, the same parts as in the first embodiment shown in FIGS. 1 to 6 are denoted by the same reference numerals, and detailed description thereof will be omitted.

(Lead frame configuration)
FIG. 10 is a sectional view showing the lead frame 10B according to the present embodiment, and FIGS. 11(a) and 11(b) are partially enlarged sectional views showing the lead frame 10B according to the present embodiment.

In the lead frame 10B shown in FIGS. 10 and 11(a) and 11(b), metal layers 27a to 27d are inserted between the die pad 11 and the resin part 18 and between the lead part 12 and the resin part 18. There is. A portion of each of the metal layers 27a to 27d may be exposed to the outside. The metal layers 27a to 27d may be formed on both the front side and the back side of the lead frame 10B (FIGS. 10 and 11(a)). The metal layers 27a and 27b may be formed only on the front surface side of the lead frame 10B (FIG. 11(b)). Alternatively, the metal layer may be formed only on the back side of the lead frame 10B (not shown).

As shown in FIGS. 10 and 11(a) and (b), the metal layer 27a is inserted between the die pad 11 and the resin portion 18 on the front surface side. Specifically, the metal layer 27a is inserted between the stepped top surface 11f of the die pad 11 and the resin surface 18a of the resin portion 18. The metal layer 27a extends on the resin surface 18a of the resin portion 18 and reaches the step side surface 11g, but does not need to reach the step side surface 11g. The metal layer 27a may have an L-shape when viewed in cross section. Further, the metal layer 27a extends on the resin side surface 18c of the resin portion 18.

As shown in FIGS. 10 and 11(a) and (b), the metal layer 27b is inserted between the lead portion 12 and the resin portion 18 on the front surface side. Specifically, the metal layer 27b is inserted between the internal terminal back surface 51b of the lead portion 12 and the resin surface 18a of the resin portion 18. The metal layer 27b extends on the resin surface 18a of the resin portion 18. The metal layer 27b does not reach the inner surface 53d of the external terminal. The metal layer 27b may extend linearly in cross-sectional view.

As shown in FIGS. 10 and 11(a), the metal layer 27c is inserted between the die pad 11 and the resin portion 18 on the back side. Specifically, the metal layer 27c is inserted between the stepped side surface 11g of the die pad 11 and the resin side surface 18c of the resin portion 18. Although the metal layer 27c does not reach the step top surface 11f, it may reach the step top surface 11f. The metal layer 27c may be integrated with the metal layer 27a located on the front side. Further, the metal layer 27c extends on the resin back surface 18b of the resin portion 18. The metal layer 27c may be L-shaped in cross-sectional view.

As shown in FIGS. 10 and 11(a), the metal layer 27d is inserted between the lead portion 12 and the resin portion 18 on the back side. Specifically, the metal layer 27d is inserted between the external terminal inner surface 53d of the lead portion 12 and the resin side surface 18c of the resin portion 18. Although the metal layer 27d does not reach the back surface 52b of the connection portion, it may reach the back surface 52b of the connection portion. Further, the metal layer 27d extends on the resin back surface 18b of the resin portion 18. The metal layer 27d may have an L-shape when viewed in cross section.

The metal layers 27a to 27d may be plating layers. The metal constituting the metal layers 27a to 27d may be, for example, silver, copper, or solder (tin alloy). The metal layers 27a to 27d may be made of the same type of metal as the plating layer 25.

The metal layers 27a to 27d may enter only one of the spaces between the die pad 11 and the resin section 18 and the space between the lead section 12 and the resin section 18.

(Configuration of semiconductor device)
The semiconductor device manufactured using the lead frame 10B according to this embodiment is substantially the same as the semiconductor device 20 according to the first embodiment described above, except that metal layers 27a to 27d are included.

(Lead frame manufacturing method)
Next, a method for manufacturing the lead frame 10B shown in FIGS. 10 and 11(a) will be described using FIGS. 12(a) to 12(d). In FIGS. 12(a)-(d), the same parts as in FIGS. 5(a)-(i) are given the same reference numerals, and detailed description thereof will be omitted.

First, a metal substrate 31 having a die pad 11, lead portions 12, and support leads 13 is manufactured in substantially the same manner as the steps shown in FIGS. 5(a) to 5(h) described above. A resin portion 18 is arranged around the die pad 11 and the lead portion 12 (FIG. 12(a)).

Next, plating resist layers 34 and 35 are provided on the front and back sides of the metal substrate 31, respectively (FIG. 12(b)). At this time, the plating resist layer 34 on the front side covers the die pad side surface 11c of the die pad 11, the lead side surface 51c of the lead portion 12, the internal terminal outer surface 51d, the connecting portion surface 52a, and the external terminal surface 53a. On the other hand, the die pad surface 11a of the die pad 11, the internal terminal surface 15 of the lead part 12, and the resin surface 18a of the resin part 18 are not covered with the plating resist layer 34, and the metal substrate 31 is exposed. Further, the plating resist layer 35 on the back surface side covers the die pad back surface 11b of the die pad 11 and the external terminal surface 17 of the lead portion 12. On the other hand, the metal substrate 31 is exposed on the resin back surface 18b of the resin portion 18 without being covered with the plating resist layer 35.

Note that when the metal layers 27c and 27d are not formed on the back side of the lead frame 10B (FIG. 11(b)), the entire area on the back side of the metal substrate 31, including the resin back side 18b of the resin part 18, is coated with the plating resist layer 35. You can cover it with

Subsequently, electrolytic plating is applied to areas of the metal substrate 31 that are not covered by the plating resist layers 34 and 35 (FIG. 12(c)). As a result, metal (for example, silver) is deposited on the internal terminal surface 15 of the lead portion 12 to form the plating layer 25. Further, on the front surface side, metal (for example, silver) is deposited in the gap between the die pad 11 and the resin part 18 and in the gap between the lead part 12 and the resin part 18. As a result, the metal layers 27a and 27b enter between the die pad 11 and the resin part 18 and between the lead part 12 and the resin part 18, respectively. Similarly, on the back side, metal (for example, silver) is deposited in the gap between the die pad 11 and the resin part 18 and in the gap between the lead part 12 and the resin part 18. As a result, the metal layers 27a to 27d enter between the die pad 11 and the resin part 18 and between the lead part 12 and the resin part 18, respectively.

Thereafter, the plating resist layers 34 and 35 are peeled off to obtain the lead frame 10B shown in FIGS. 10 and 11(a) (FIG. 12(d)).

(Method for manufacturing semiconductor devices)
The method for manufacturing the semiconductor device according to this embodiment can be performed in substantially the same manner as the method for manufacturing the semiconductor device 20 shown in FIGS. 6(a) to 6(e).

According to this embodiment, the metal layers 27a to 27d are inserted between the die pad 11 and the resin part 18 and between the lead part 12 and the resin part 18. This prevents moisture from entering the semiconductor element 21 side from the interface between the die pad 11 and the resin part 18 or the interface between the lead part 12 and the resin part 18. As a result, the reliability of the semiconductor device after long-term use can be improved.

(Fourth embodiment)
Next, a fourth embodiment will be described with reference to FIGS. 13 to 15. 13 to 15 are diagrams showing the fourth embodiment. In the fourth embodiment shown in FIGS. 13 to 15, metal layers 27e to 27h are mainly inserted between the die pad 11 and the resin part 18 or between the lead part 12 and the resin part 18. This embodiment is different in this point, and the other configurations are substantially the same as the second embodiment described above. 13 to 15, the first embodiment shown in FIGS. 1 to 6, the second embodiment shown in FIGS. 7 to 9, and the third embodiment shown in FIGS. 10 to 12. Identical parts are given the same reference numerals and detailed explanations are omitted.

(Lead frame configuration)
FIG. 13 is a sectional view showing a lead frame 10C according to this embodiment, and FIGS. 14(a) and 14(b) are partially enlarged sectional views showing the lead frame 10C according to this embodiment.

In the lead frame 10C shown in FIGS. 13 and 14(a) and 14(b), metal layers 27e to 27h are inserted between the die pad 11 and the resin portion 18 and between the lead portion 12 and the resin portion 18. There is. The metal layers 27e to 27h may be formed on both the front side and the back side of the lead frame 10C (FIGS. 13 and 14(a)). A portion of each of the metal layers 27e to 27h may be exposed to the outside. The metal layers 27e and 27f may be formed only on the front surface side of the lead frame 10C (FIG. 14(b)). Alternatively, the metal layer may be formed only on the back side of the lead frame 10C (not shown).

As shown in FIGS. 13 and 14(a) and (b), the metal layer 27e is inserted between the lead portion 12 and the resin portion 18 on the front surface side. Specifically, the metal layer 27e is inserted between the lead side surface 51c of the lead portion 12 and the resin side surface 18c of the resin portion 18. The metal layer 27e does not need to reach the lead protrusion 51e. The metal layer 27e may be integrated with the plating layer 25.

As shown in FIGS. 13 and 14(a) and (b), the metal layer 27f is inserted between the lead portion 12 and the resin portion 18 on the front surface side. Specifically, the metal layer 27f is inserted between the inner terminal outer surface 51d of the lead portion 12 and the resin side surface 18c of the resin portion 18. Although the metal layer 27f does not reach the connecting portion surface 52a, it may reach the connecting portion surface 52a. The metal layer 27f may be integrated with the plating layer 25.

As shown in FIGS. 13 and 14(a), the metal layer 27g is inserted between the die pad 11 and the resin portion 18 on the back side. Specifically, the metal layer 27g is inserted between the die pad side surface 11c of the die pad 11 and the resin side surface 18c of the resin portion 18. The metal layer 27g extends from the die pad protrusion 11h toward the die pad surface 11a side. The metal layer 27g does not need to reach the die pad surface 11a. Further, the metal layer 27g extends on the resin back surface 18b of the resin portion 18.

As shown in FIGS. 13 and 14(a), the metal layer 27h is inserted between the lead portion 12 and the resin portion 18 on the back side. Specifically, the metal layer 27h is inserted between the lead side surface 51c of the lead portion 12 and the resin side surface 18c of the resin portion 18. The metal layer 27h extends from the lead protrusion 51e toward the internal terminal surface 15 side. Although the metal layer 27h does not reach the internal terminal surface 15, it may reach the internal terminal surface 15. The metal layer 27h may be integrated with the metal layer 27e located on the front side. Further, the metal layer 27h extends on the resin back surface 18b of the resin portion 18.

The metal layers 27e to 27h may be plating layers. The metal constituting the metal layers 27e to 27h may be, for example, silver, copper, or solder (tin alloy). The metal layers 27e to 27h may be made of the same type of metal as the plating layer 25.

The metal layers 27e to 27h may enter only one of the spaces between the die pad 11 and the resin section 18 and between the lead section 12 and the resin section 18.

(Configuration of semiconductor device)
The semiconductor device manufactured using the lead frame 10C according to this embodiment is substantially the same as the semiconductor device 20 according to the first embodiment described above, except that metal layers 27e to 27h are included.

(Lead frame manufacturing method)
Next, a method for manufacturing the lead frame 10C shown in FIGS. 13 and 14(a) will be described using FIGS. 15(a) to 15(d). In FIGS. 15(a)-(d), the same parts as in FIGS. 9(a)-(i) are given the same reference numerals, and detailed description thereof will be omitted.

First, a metal substrate 31 having a die pad 11, lead portions 12, and support leads 13 is manufactured in substantially the same manner as the steps shown in FIGS. 9(a) to 9(h) described above. A resin portion 18 is arranged around the die pad 11 and the lead portion 12 (FIG. 15(a)).

Next, plating resist layers 34 and 35 are provided on the front and back sides of the metal substrate 31, respectively (FIG. 15(b)). At this time, the plating resist layer 34 on the front side covers the die pad surface 11a of the die pad 11. On the other hand, the internal terminal surface 15 of the lead part 12 and the resin surface 18a of the resin part 18 are not covered with the plating resist layer 34 and the metal substrate 31 is exposed. Further, the plating resist layer 35 on the back side includes the die pad back surface 11b of the die pad 11, the step top surface 11f, the step side surface 11g, the internal terminal back surface 51b of the lead section 12, the connection section back surface 52b, the external terminal inner surface 53d, Covers the external terminal surface 17. On the other hand, the metal substrate 31 is exposed on the resin back surface 18b of the resin portion 18 without being covered with the plating resist layer 35.

Note that when the metal layers 27g and 27h are not formed on the back side of the lead frame 10C (FIG. 14(b)), the entire area on the back side of the metal substrate 31, including the resin back side 18b of the resin part 18, is coated with the plating resist layer 35. You can cover it with

Subsequently, electrolytic plating is applied to areas of the metal substrate 31 that are not covered by the plating resist layers 34 and 35 (FIG. 15(c)). As a result, metal (for example, silver) is deposited on the internal terminal surface 15 of the lead portion 12 to form the plating layer 25. Further, on the front surface side, metal (for example, silver) is deposited in the gap between the die pad 11 and the resin part 18 and in the gap between the lead part 12 and the resin part 18. As a result, the metal layers 27e to 27h enter between the die pad 11 and the resin part 18 and between the lead part 12 and the resin part 18, respectively. Similarly, on the back side, metal (for example, silver) is deposited in the gap between the die pad 11 and the resin part 18 and in the gap between the lead part 12 and the resin part 18. As a result, the metal layers 27e to 27h enter between the die pad 11 and the resin part 18 and between the lead part 12 and the resin part 18, respectively.

Thereafter, the plating resist layers 34 and 35 are peeled off to obtain a lead frame 10C shown in FIGS. 13 and 14(a) (FIG. 15(d)).

(Method for manufacturing semiconductor devices)
The method for manufacturing the semiconductor device according to this embodiment can be performed in substantially the same manner as the method for manufacturing the semiconductor device 20 shown in FIGS. 6(a) to 6(e).

According to this embodiment, the metal layers 27e to 27h are inserted between the die pad 11 and the resin part 18 and between the lead part 12 and the resin part 18. This prevents moisture from entering the semiconductor element 21 side from the interface between the die pad 11 and the resin part 18 or the interface between the lead part 12 and the resin part 18. As a result, the reliability of the semiconductor device after long-term use can be improved.

It is also possible to combine the plurality of components disclosed in each of the above embodiments and modifications as appropriate. Alternatively, some components may be deleted from all the components shown in the above embodiments and modifications.

10 lead frame 10a package area 11 die pad 12 lead part 13 support lead (support member)
14 Hanging lead 15 Internal terminal surface 17 External terminal surface 18 Resin part 20 Semiconductor device 51 Internal terminal 52 Connection part 53 External terminal

Claims (10)

In the lead frame,
die pad and
a lead portion disposed around the die pad;
a resin part disposed around the die pad and the lead part,
The lead portion has an internal terminal located on the die pad side, an external terminal located on the opposite side of the die pad, and a connecting portion located between the internal terminal and the external terminal,
The internal terminal is thinned from the back side, the external terminal is thinned from the front side, and the connection part is thinned from both the front side and the back side. The lead frame according to claim 1, wherein the resin part is located on the back side of the internal terminal and the connection part. 3. The lead frame according to claim 2, wherein a surface of a portion of the resin portion located between the lead portion and the die pad is located on the same plane as a back surface of the internal terminal and a back surface of the connection portion. The lead frame according to claim 1, wherein the resin portion is located on the surface side of the connection portion and the external terminal. 5. The lead frame according to claim 4, wherein a back surface of a portion of the resin section located between the lead section and the die pad is located on the same plane as a back surface of the internal terminal and a back surface of the connection section. The lead frame according to claim 1, wherein the die pad has a stepped portion located on the back side, and the stepped portion is in close contact with the resin portion. The lead frame according to claim 1, wherein the thickness of the connecting portion is 10% or more and 45% or less of the maximum thickness of the lead frame. The lead frame according to claim 1, wherein a metal layer is inserted between the die pad and the resin part or between the lead part and the resin part. In the lead frame manufacturing method,
a step of preparing a metal substrate;
forming a back side recess by etching the metal substrate from the back side of the metal substrate to the middle of the thickness direction;
forming a resin part on the back side of the metal substrate, and covering the back side recess with the resin part;
forming a die pad and a lead portion disposed around the die pad by etching the metal substrate from the front surface side of the metal substrate to the middle of the thickness direction;
a step of polishing the resin part by a predetermined thickness,
The lead portion has an internal terminal located on the die pad side, an external terminal located on the opposite side of the die pad, and a connecting portion located between the internal terminal and the external terminal,
In the step of etching from the surface side of the metal substrate, the resin portion located between the die pad and the lead portion is exposed to the surface side, and the external terminal and the connection portion are thinned from the surface side. , a lead frame manufacturing method. In the lead frame manufacturing method,
a step of preparing a metal substrate;
forming a surface-side recess by etching the metal substrate from the surface side of the metal substrate to the middle of the thickness direction;
forming a resin part on the front side of the metal substrate, and covering the front side recess with the resin part;
polishing the resin part to a predetermined thickness;
forming a die pad and a lead portion disposed around the die pad by etching the metal substrate from the back side of the metal substrate to the middle of the thickness direction,
The lead portion has an internal terminal located on the die pad side, an external terminal located on the opposite side of the die pad, and a connecting portion located between the internal terminal and the external terminal,
In the step of etching the metal substrate from the back side, the resin portion located between the die pad and the lead portion is exposed to the back side, and the internal terminals and the connection portions are thinned from the back side. , a lead frame manufacturing method.

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