JP7292776B2 - Lead frame - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lead frame used for manufacturing a semiconductor package of a type in which terminals for external connection on the back side are connected to an external device such as a printed circuit board.

2. Description of the Related Art When a semiconductor package is incorporated into an external device, there is a demand for visualization of the soldered connection portion so that the quality of the soldered connection between the semiconductor package and the external device can be visually inspected.

Conventionally, in a semiconductor package of, for example, a QFN (Quad-Flat No-leaded) type that does not have outer leads on the outer periphery, terminals for external connection are arranged on the back side of the semiconductor package and are exposed on the back side of the semiconductor package. Because of the structure in which a plurality of external connection terminals are connected to an external device such as a printed circuit board, it is difficult to visually inspect whether or not they are soldered.

However, if a visual inspection of the soldered connection portion is not possible, the connection failure inherent in the soldering work will be overlooked, and the operation cost until the connection failure is discovered in the subsequent energization inspection or the like will be extra. Also, although it is possible to carry out a fluoroscopic inspection of the soldered joint using an X-ray apparatus, this would increase the equipment cost of the X-ray apparatus.

Therefore, conventionally, as a technique for making it possible to visually inspect whether the solder connection state is good or bad in the solder connection part of a QFN type semiconductor package, Patent Document 1 discloses one surface side (back surface) of a lead in a lead frame. By forming grooves that traverse the leads at the cutting positions of the terminals that will be the external connection terminals on the side), the external connection terminals exposed on the back surface of the semiconductor package when cut individually can be cut from the edges. It has been proposed to provide a space between the semiconductor package and insert solder in the space so that the soldered connection portion can be seen from the external connection terminal exposed on the side surface of the semiconductor package.

Further, in Patent Document 2, a concave portion is provided inside a predetermined region that straddles the boundary line of the cut region, including a region that serves as an external connection terminal of the lead on one side surface (back surface) of the lead frame, and the surface side After encapsulating with resin, cutting is performed at a position where the surface of the recess can be exposed, so that the exposed side surface of the external connection terminal has a gate shape, and from the external connection terminal exposed on the side surface of the semiconductor package Techniques have been disclosed for making soldered connections visible.

JP-A-2000-294715 JP 2018-200994 A

However, in the technique of forming a groove across the lead described in Patent Document 1, resin enters the groove during resin sealing, and a space for making the solder connection portion visible is not formed, resulting in a semiconductor package. There is a possibility that the yield of the product will deteriorate.

Regarding this point, according to the technology for forming the side surface of the external connection terminal into a gate shape described in Patent Document 2, it is possible to obtain a space that allows the solder connection portion to be visually observed. It is desired to further increase the opening area of the side surface to make the soldered connection portion easier to see.

In order to facilitate visual inspection of the soldered connection portion, if the opening area of the gate-shaped side surface of the external connection terminal in the lead frame configured as described in Patent Document 2 is increased as much as possible, the lead can be partially removed. Since the thickness is extremely thin, the strength is insufficient, and there is a risk of deformation during the assembly process of the semiconductor package.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art. An object of the present invention is to provide a lead frame capable of preventing deformation due to strength reduction.

In order to achieve the above object, the lead frame according to the present invention is a lead frame used in a semiconductor package in which terminals for external connection are exposed on one surface and side surfaces, and is formed of a metal plate made of a copper-based material. of the metal plate on one side of the lead, in a first region that includes a part of the region that becomes the external connection terminal and that straddles the boundary line of the cutting region for cutting into individual packages. It has a thin portion formed by a recess with a depth of 75 to 90% of the thickness of the metal plate, and a recessed reinforcing plating layer on the surface of the thin portion has a depth of 7.5% or more of the thickness of the metal plate. An external connection plating layer is formed on a surface of a second region including the first region formed with a thickness and having the reinforcement plating layer formed thereon. The surface of the plating layer for external connection at the position of the recessed bottom portion of the boundary line of the cutting area is located at a depth of approximately 50% or more of the thickness of the metal plate from one side of the metal plate. Characterized by

Further, in the lead frame of the present invention, the reinforcing plating layer is a plating layer containing nickel, and the thickness of the plating layer at the portion where the reinforcing plating layer and the plating layer for external connection are laminated is It is preferably 10% or more of the plate thickness of the metal plate. A realistic range of the thickness is approximately 5 to 55 μm.

Moreover, in the lead frame of the present invention, it is preferable that the side surface of the lead has a portion where the reinforcing plating layer is exposed from the metal plate.

Moreover, in the lead frame of the present invention, it is preferable that the reinforcing plating layer is exposed on the side surface of the lead at the position of the boundary line of the cutting area.

According to the present invention, it is possible to increase as much as possible the opening area of the gate-shaped side surface of the semiconductor package product, which is a portion that allows the solder connection portion to be visually observed, and at the same time, it is possible to prevent deformation due to a decrease in the strength of the lead. A lead frame is obtained.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory diagram showing the essential configuration of the lead frame according to the first embodiment of the present invention, where (a) is a view from one side (the side connected to an external device), and (b) is different from (a). View from the opposite side, (c) is an AA cross-sectional view of the region to be the external connection terminal in the lead frame of (a), (c') is a partial enlarged view of (c), (d) is (a ) is a BB cross-sectional view of the area to be the external connection terminal in the lead frame, (e) is a view from the side connected to the external device showing the modification, and (f) is a CC cross-sectional view of (e). is. 1. It is explanatory drawing which shows an example of the manufacturing procedure of the lead frame of FIG. 1 by the AA cross section of Fig.1 (a). 1. It is explanatory drawing which shows an example of the manufacturing procedure of the lead frame of FIG. 1 by the BB cross section of Fig.1 (a). FIG. 4 is an explanatory diagram showing an example of a manufacturing procedure of a package using a lead frame manufactured by the manufacturing procedure of FIGS. 2 and 3; FIG. 5 is a side view seen from the same side as FIG. 4(e), showing a state in which the external connection terminals of the semiconductor package manufactured by the manufacturing procedure of FIG. 4 are soldered to an external device; FIG.

Hereinafter, with reference to the drawings, description will be given of a mode for carrying out the present invention.

FIRST EMBODIMENT As shown in FIG. 1, the lead frame 1 of the first embodiment is formed of a metal plate made of a copper-based material. and has a thin portion 11-1a in a region 11-1 that straddles the boundary line L of the cutting region for cutting into individual packages and intersects the dam bar 13. As shown in FIG.
As shown in FIGS. 1(c) and 1(c'), the thin portion 11-1a is formed by a recess having a depth of 75 to 90% of the plate thickness of the metal plate 10 on one side. .
In addition, on the surface (inner surface) of the thin portion 11-1a, a concave reinforcement plating layer 14 made of a plating layer containing nickel has a thickness of 7.5% or more of the thickness of the metal plate 10. formed.
An external connection plating layer 12 is formed on the surface of one side of the second region 11-2 including the first region 11-1 on which the reinforcing plating layer 14 is formed.
The thickness of the plated layer at the portion where the reinforcing plated layer 14 and the external connection plated layer 12 are laminated is 10% or more of the plate thickness of the metal plate 10 .
In addition, the surface of the external connection plating layer 12 at the position of the recessed bottom portion of the boundary line L of the cutting area of the lead 11 is approximately 50% or more of the plate thickness of the metal plate 10 from one surface side of the metal plate 10. located at the depth of
The plating layer 12 for external connection is preferably composed of a plating layer in which nickel, palladium and gold are laminated in this order.
Further, as shown in FIG. 1(d), the thin portion 11-1a is formed in a concave shape such that the BB cross section of FIG. 1(a) has a gate shape. e), as shown in FIG.

Next, an example of the manufacturing process of the lead frame of this embodiment shown in FIG. 1 will be described with reference to FIGS. 2 and 3. FIG.
First, a metal plate 10 made of a copper-based material is prepared (see FIGS. 2(a) and 3(a)).
Next, the metal plate 10 is half-etched to form the concave portion 11-1b.
Specifically, a first resist layer R1 such as a dry film resist is formed on both surfaces of the metal plate 10 (see FIGS. 2(b) and 3(b)). Next, the entire surface of the first resist layer R1 on the other surface side of the metal plate 10 is exposed, and the first resist layer on the one surface side of the metal plate 10 is exposed using a glass mask on which a predetermined pattern is drawn. R1 is exposed and developed to form an etching/plating resist mask 31 that has an opening at a portion corresponding to the thin portion 11-1a and covers the other portion (FIGS. 2(c) and 3(c)). c)). Next, using an etchant, the metal plate 10 is half-etched from one side to a depth of 75 to 90% of the plate thickness of the metal plate 10, and the concave portion 11-1b is formed on the one side of the metal plate 10. is formed (see FIGS. 2(d) and 3(d)). The width of the inner surface of this recess 11-1b is formed to be 50 to 100% of the width of the lead 11 according to the width of the lead 11. FIG. If the width of the inner surface of the recess 11-1b is formed to be 100% (or more than 100%) of the width of the lead 11, the reinforcement plating layer will not be exposed on the side surface of the lead 11 when the lead frame shape is formed in a post-process. can be done.
Next, plating containing nickel or a nickel alloy having a thickness of 7.5% or more of the thickness of the metal plate 10 is applied to the surface (inner surface) of the recess 11-1b from one surface side of the metal plate 10 to form a concave shape. A reinforcing plating layer 14 is formed (see FIGS. 2(e) and 3(e)). Then, the etching/plating resist mask 31 formed on the metal plate 10 is removed (see FIGS. 2(f) and 3(f)).

Next, three types of processes for forming the internal connection plating layer and the external connection plating layer will be briefly described.
First, in the case of a lead frame that requires the plating layer of the same material for the plating layer for internal connection and the plating layer for external connection, plating is performed by forming a resist mask with openings on both sides where the plating layer is to be formed. . For example, nickel, palladium, and gold are plated in this order, and then the resist masks on both sides are removed.
In the case of a lead frame that requires plating layers of different materials for the plating layer for internal connection and the plating layer for external connection, form a resist mask with an opening on the other side where the plating layer for internal connection is to be formed. On one side, a resist mask is formed to cover the entire surface, plating is performed, for example, silver plating is applied to form a plating layer for internal connection, and then the resist masks on both sides are removed. Next, a resist mask covering the entire surface is formed on the other surface side, and a resist mask is formed on the one surface side so that a portion for forming a plating layer for external connection is opened, and plating is performed. Palladium and gold are plated in this order, and then the resist masks on both sides are removed.
In the case of a lead frame that does not have a plating layer for internal connection and requires only a plating layer for external connection, a resist mask is formed to cover the entire surface on the other side, and one side is plated for external connection. A resist mask with openings for forming layers is formed, plating is performed, for example, nickel, palladium, and gold are plated in this order, and then the resist masks on both sides are removed.

Here, the process of forming the plating layer for external connection will be described again with reference to FIGS. 2 and 3. FIG.
A second resist layer R2 such as a dry film resist is formed on both surfaces of the metal plate 10 (see FIGS. 2(g) and 3(g)). Next, the entire surface of the second resist layer R2 on the other side is exposed, and the second resist layer R2 on the one side is exposed using a glass mask having a predetermined pattern drawn thereon, developed, and read. A plating resist mask 32 is formed by opening a portion corresponding to the second region 11-2 of 11 and covering other portions (see FIGS. 2(h) and 3(h)).
Next, the portions exposed from the plating resist mask 32 are plated with, for example, nickel, palladium, and gold in this order (see FIGS. 2(i) and 3(i)). As a result, the external connection plating layer 12 is formed on the surface of one side of the second region 11-2 including the first region on which the concave reinforcement plating layer 14 is formed.
When forming the plating layer 12 for external connection, the surface of the plating layer 12 for external connection at the position of the recessed bottom of the boundary line L of the cutting area of the lead 11 is cut from one surface side of the metal plate 10 to the metal plate 10 . The thickness of the plating is adjusted so that the depth is approximately 50% or more of the plate thickness of the plate 10 .
At this time, preferably, the total thickness of the reinforcement plating layer 14 and the external connection plating layer 12 is 10% or more of the thickness of the metal plate 10 . A realistic range of the thickness is approximately 5 to 55 μm.
Also, the surface of the plating layer 12 for external connection may be formed as a roughened surface. When forming a roughened surface, for example, the nickel plating layer of the external connection plating layer 12 may be formed by roughening plating. Further, for example, after forming a smooth nickel plating layer, the surface of the nickel plating layer may be etched to form a roughened surface. Further, a plated layer of palladium and gold may be laminated in this order on the nickel plated layer having the roughened surface.
Thereafter, the plating resist masks 32 on both sides are removed (see FIGS. 2(j) and 3(j)).

Next, the metal plate 10 is etched to form a lead frame shape.
Specifically, a third resist layer R3 such as a dry film resist is formed on both surfaces of the metal plate 10 (see FIG. 3(k)). Next, the third resist layer R3 on the other side of the metal plate 10 and the third resist layer R3 on the one side of the metal plate 10 are removed using a glass mask having a predetermined pattern necessary for obtaining a lead frame shape. By exposing and developing, etching resist masks 33 are formed on both sides of the metal plate 10 (see FIG. 3(l)).
Next, the metal plate 10 is etched from both sides using an etchant to form a multi-row lead frame in which the individual lead frame regions are connected to the dam bars 13 and cut into individual semiconductor packages. A lead frame is formed in which the cross-sectional shape of the terminal portion, which becomes the external connection terminal when closed, is gate-shaped (see FIG. 3(m)).
Next, the etching resist mask 33 is removed (see FIG. 3(n)).
Thus, the lead frame 1 of this embodiment is completed.
When the lead frame 1 is formed by etching, intermediate portions of the leads and other required portions may be half-etched.

Next, a procedure for manufacturing a semiconductor device using the lead frame of this embodiment will be briefly described with reference to FIGS. 4 and 5. FIG.
A semiconductor element is mounted on the other side of the lead frame of this embodiment, and the electrodes of the semiconductor element and predetermined internal connection terminals are wire-bonded or flip-chip mounted (not shown).
Next, a sheet-like masking tape m1 is attached to one surface side (see FIG. 4(a)), a molding die (not shown) is set, and the semiconductor element mounting side is sealed with resin 21 (see FIG. 4(a)). b)), at this time, one end face of the recessed portion formed by laminating the reinforcing plating layer 14 and the plating layer 12 for external connection is in close contact with the masking tape m1, and the inside is sealed. state. Therefore, when the sealing resin is formed, the resin 21 does not enter the recessed portion formed by laminating the reinforcing plating layer 14 and the plating layer 12 for external connection.
Next, the masking tape m1 is removed (see FIG. 4(c)) and cut into a predetermined size of the semiconductor device 40 (see FIGS. 4(d) and 4(d')). As a result, the semiconductor device 40 using the lead frame of this embodiment is completed (see FIG. 4(e)).
When the terminals for external connection of the semiconductor package 40 using the lead frame 1 of the present embodiment thus obtained are soldered to the terminals 81 of the printed circuit board 80, the solder 90 is exposed on the side surface of the semiconductor package 40 for external connection. The solder connection portion can be visually confirmed through the gate-shaped opening of the terminal, and the connection state can be visually inspected for good or bad (see FIG. 5).

According to the lead frame 1 of this embodiment, when the semiconductor package is soldered to an external device, the solder connection portion can be visually confirmed from the side, and the thickness is 7.5% or more of the plate thickness of the metal plate 10. By forming the reinforcing plating layer 14, even if the gate-shaped opening area is formed larger (wider) than before, the strength of the lead 11 does not decrease, and deformation occurring in the manufacturing process of the semiconductor package can be prevented. Then, when cutting is performed with a blade along the boundary line L of the cutting area, the cut surface, which is the side surface of the semiconductor package, has a large gate-shaped opening area, so that the amount of the copper-based material is reduced. It is possible to reduce burrs caused by the copper-based material in the external connection terminals exposed on the side surface of the semiconductor package, which has conventionally occurred.
Further, when the width of the inner surface of the concave portion 11-1b formed by the half-etching process described above is formed to the width of the lead 10 (100%), the cut surface that becomes the side surface of the semiconductor package covers most of the side surface of the lead 11. becomes a reinforcing plating layer and a plating layer for external connection, and the amount of copper-based material existing on the side is greatly reduced (only the side of the copper-based material existing on the other side), so the occurrence of burrs due to the copper-based material is minimized. can be further suppressed.
As a result, the productivity of the step of cutting into individual semiconductor packages with a blade is also improved.

Example 1
First, a copper-based material having a thickness of 0.2 mm was prepared as the metal plate 10 (see FIGS. 2(a) and 3(a)), and a dry film resist was laminated on both sides as a first resist layer R1 ( 2(b) and 3(b)).
Next, exposure and development are performed to form an etching/plating resist mask 31 covering the entire surface on the other surface side (front surface side), and on one surface side (rear surface side), the lead frame shown in FIG. An etching/plating resist mask 31 having an opening at a portion corresponding to the thin portion 11-1a and covering other portions was formed (see FIGS. 2(c) and 3(c)).
Next, half-etching is performed using an etchant to form a concave portion 11-1b on one side of the metal plate 10 (see FIGS. 2(d) and 3(d)). As conditions for the half-etching process, the recesses 11-1b have a depth of 85% of the plate thickness of the metal plate 10, and 60% of the width of the leads 11 (to be formed later) on both sides in the width direction. It was set to have a width of copper-based material.
After forming the concave portion 11-1b on one side of the metal plate 10, plating is performed using the same etching/plating resist mask 31, and the concave portion 11-1b (inner surface) is nickel plated with a set thickness of 19 μm. , a recessed reinforcement plated layer 14 with an opening on one side was formed (see FIGS. 2(e) and 3(e)).
Thereafter, the etching/plating resist mask 31 on both sides was removed (see FIGS. 2(f) and 3(f)).

Next, a dry film resist was laminated as a second resist layer R2 on both surfaces of the copper-based metal plate 10 (see FIGS. 2(g) and 3(g)).
Then, using a glass mask on which a predetermined pattern is drawn, exposure and development are performed, and on the other side, portions corresponding to regions (not shown) to be internal connection terminals are opened, and other portions are opened. A portion corresponding to the second region 11-2 including the first region 11-1 formed with the plating resist mask 32 and having the recessed reinforcement plating layer 14 formed on one surface side , and a resist mask 32 for plating was formed covering the other portions (see FIGS. 2(h) and 3(h)).
Next, plating is performed, and nickel plating with a set thickness of 1 μm, palladium plating with a set thickness of 0.01 μm, and gold plating with a set thickness of 0.001 μm are applied in order, so that the area that becomes the internal connection terminal of the lead 11 is formed. (not shown), an internal connection plating layer (not shown) was formed on the surface of the second region 11-2, and an external connection plating layer 12 was formed on the surface of the second region 11-2 (Fig. i)). By this plating process, the external connection plating layer 12 is laminated on the previously formed recessed reinforcing plating layer 14 .
After that, the resist masks 32 on both sides were removed (see FIGS. 2(j) and 3(j)).

Next, a dry film resist was laminated as a third resist layer R3 on both surfaces of the metal plate 10 (see FIG. 3(k)).
Next, exposure and development are carried out, and the other side has a portion that will become a predetermined lead frame, including a portion in which nickel, palladium, and gold plating are laminated in order as internal connection terminals, and a portion that will become a dam bar. is covered and other parts are exposed. An etching resist mask 33 was formed to cover the portion to be the lead frame and expose the other portions (see FIG. 3(l)).
Next, an etching process was performed to form a predetermined lead frame and dambar shape from the metal plate 10 (see FIG. 3(m)).
After that, the resist masks 33 on both sides were removed (see FIG. 3(n)).
The boundary line L of the cutting area for cutting the lead 11 connected to the dam bar 13 into individual packages having terminals for internal connection on the other side and terminals for external connection on one side. is formed of the metal plate 10, the reinforcing plating layer 14, and the plating layer 12 for external connection, and on one surface side, a concave opening is provided inside the plating layer 12 for external connection. obtained a lead frame.
In the obtained lead frame of Example 1, it was confirmed that there was no deformation of the lead 11 having the concave opening.

Example 2
Preparation of the metal plate 10 to formation of the etching/plating resist mask 31 are performed in substantially the same manner as in the first embodiment. An etching/plating resist mask 31 having an opening with the same width as the width is used, half-etching is performed to the same depth as in Example 1, and a concave portion 11-1b is formed on one side of the metal plate 10, By applying nickel plating with a set thickness of 15 μm, a recessed reinforcement plating layer 14 with an opening on one side was formed.
Subsequent steps are performed in the same manner as in Example 1, so that individual packages of leads 11 having terminals for internal connection on the other side and terminals for external connection on one side and connected to dam bars 13 are formed. The portion straddling the boundary line L of the cutting area for cutting into two is formed of the metal plate 10, the reinforcing plating layer 14, and the external connection plating layer 12 as in the first embodiment, but the metal plate 10 is formed on the other surface side. , the reinforcing plating layer 14 on the side surface, the side surface of the metal plate 10 on the other surface side, and the external connection plating layer 12 on the one surface side were exposed, respectively.
In the obtained lead frame of Example 2, it was confirmed that there was no deformation of the lead 11 having the concave opening.

Comparative example 1
After preparing the metal plate 10 and forming the concave portion 11-1b on one side of the metal plate 10 in the same manner as in Example 2, nickel plating with a set thickness of 11 μm is applied to the one side. An open recessed reinforcing plating layer 14 was formed.
Subsequent steps are performed in the same manner as in Example 2, so that individual packages of leads 11 having terminals for internal connection on the other side and terminals for external connection on one side and connected to dam bars 13 are formed. The portion straddling the boundary line L of the cutting area for cutting into two is formed of the metal plate 10, the reinforcing plating layer 14, and the external connection plating layer 12 as in the first embodiment, but the metal plate 10 is formed on the other surface side. , the reinforcing plating layer 14 on the side surface, the side surface of the metal plate 10 on the other surface side, and the external connection plating layer 12 on the one surface side were exposed, respectively.
In the obtained lead frame of Comparative Example 1, deformation was confirmed in several leads 11 having concave openings, and when the thickness of the reinforcing plating layer 14 was 6.5% of the thickness of the metal plate 10, the strength was low. As a result, it was recognized that there was a shortage.

Comparative example 2
The concave portion 11-1b is formed in substantially the same manner as in Example 1, but the half-etching condition is that the concave portion 11-1b has a depth of 85% of the plate thickness of the metal plate 10, and the lead 11 (to be formed later). The width of the recess 11-1b is set to 70% of the width of the recess 11-1b, and the width of both sides of the recess 11-1b in the width direction is set to be 15% of the width of the copper-based material.
Then, the etching/plating resist mask 31 was removed without forming the reinforcing plating layer 14 .
Subsequent steps are performed in the same manner as in Example 1, so that individual packages of leads 11 having terminals for internal connection on the other side and terminals for external connection on one side and connected to dam bars 13 are formed. The part that crosses the boundary line L of the cutting area for cutting is formed of the metal plate 10 and the plating layer 12 for external connection, the metal plate 10 on the other surface side and the side surface, and the metal plate 10 on the one surface side. A lead frame of Comparative Example 2 in which the plating layers 12 for external connection were exposed was obtained.
In the obtained lead frame of Comparative Example 2, deformation was confirmed in several leads 11 having recessed openings, resulting in insufficient strength.

Comparative example 3
After forming the concave portion 11-1b in the same manner as in Example 1, the etching/plating resist mask 31 was removed without forming the reinforcing plating layer .
Subsequent steps are performed in the same manner as in Example 1, so that individual packages of leads 11 having terminals for internal connection on the other side and terminals for external connection on one side and connected to dam bars 13 are formed. The part that crosses the boundary line L of the cutting area for cutting is formed of the metal plate 10 and the plating layer 12 for external connection, the metal plate 10 on the other surface side and the side surface, and the metal plate 10 on the one surface side. A lead frame of Comparative Example 3 in which the plating layers 12 for external connection were exposed was obtained.
In the obtained lead frame of Comparative Example 3, deformation was confirmed in several leads 11 having recessed openings, resulting in insufficient strength.

1 Lead frame 10 Metal plate 11 Lead 11-1 First region 11-1a Thin portion 11-1b Recess 11-2 Second region 12 External connection plating layer 13 Dam bar 14 Reinforcing plating layer 21 Sealing resin 31 Etching/ Resist mask for plating 32 Resist mask for plating 33 Resist mask for etching 40 Semiconductor package 80 External device 81 Terminal 90 Solder m1 Masking tape R1 First resist layer R2 Second resist layer R3 Third resist layer

Claims (4)

A lead frame used in a semiconductor package in which external connection terminals are exposed on one side surface and side surface,
In a first region of leads formed of a metal plate made of a copper-based material, including a part of the region to be the external connection terminal and straddling the boundary line of the cutting region for cutting into individual packages. , a thin portion formed by a recess having a depth of 75 to 90% of the plate thickness of the metal plate on one side,
A concave reinforcement plating layer is formed on the surface of the thin portion with a thickness of 7.5% or more of the thickness of the metal plate,
An external connection plating layer is formed on the surface of one side of the second region including the first region on which the reinforcing plating layer is formed,
The surface of the plating layer for external connection at the position of the recessed bottom portion of the boundary line of the cutting area of the lead is at a depth of approximately 50% or more of the thickness of the metal plate from one surface side of the metal plate. A lead frame characterized by a position. The reinforcing plating layer is a plating layer containing nickel,
2. The lead according to claim 1, wherein the thickness of the plated layer at the portion where the reinforcement plated layer and the external connection plated layer are laminated is 10% or more of the plate thickness of the metal plate. flame. 2. The lead frame according to claim 1, wherein the side surface of the lead has a portion where the reinforcing plating layer is exposed from the metal plate. 2. The lead frame according to claim 1, wherein the reinforcing plating layer is exposed on the side surface of the lead at the position of the boundary line of the cutting area.

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