JP2020053424A - Lead frame and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To visually inspect a solder connection portion of a semiconductor package for connecting a plurality of external connection terminals exposed on the back surface side to an external device, and to the extent that the burden on the operator due to the visual inspection and the inspection time can be reduced. Providing a lead frame that makes it easy to increase the amount of solder protruding from the cut surface of the connection terminal and prevents short-circuit defects of the external connection terminal due to solder bleeding. SOLUTION: This is used for manufacturing a semiconductor package provided with a plurality of external connection terminals exposed on a surface and a side surface of an external device connection side, and individual lead frames 1 are connected to a dam bar 13 and arranged in multiple rows, and are externally arranged. The terminal portion 11 serving as a connection terminal has a predetermined position near the dam bar, which extends inside the cutting region to be cut into each lead frame, in a stepwise or continuous manner from the vicinity of the cutting region toward the opposite side of the cutting region. Therefore, a recess 11b having a predetermined opening shape having a region having a shallow depth and a narrow width is formed. [Selection diagram] Fig. 1

Description

  The present invention relates to a lead frame used for manufacturing a semiconductor package of a type in which an external connection terminal on a back side is connected to an external device such as a printed circuit board, and a method for manufacturing the same.

  When a semiconductor package is incorporated into an external device, visualization of a solder connection portion is required so that a good or bad solder connection state between the semiconductor package and the external device can be visually inspected.

  However, conventionally, for example, a QFN (Quad-Flat No-leaded) type semiconductor package having no leads on the outer peripheral portion has terminals for external connection arranged on the back side of the semiconductor package and is exposed on the back side of the semiconductor package. In this case, it is difficult to visually inspect whether or not the plurality of external connection terminals are normally connected by soldering.

  However, if the visual inspection of the solder connection portion cannot be performed, the connection failure inherent in the solder connection operation is overlooked, and the operation cost until a connection failure is found in a subsequent energization test or the like is increased. Further, although it is possible to perform a fluoroscopic inspection on the solder connection portion using an X-ray device, the equipment cost of the X-ray device increases.

  For example, Japanese Patent Application Laid-Open No. H11-163873 discloses a conventional technique for visually inspecting the quality of solder connection at a solder connection portion of a QFN type semiconductor package. By forming a groove that traverses the lead at the cutting position of the terminal portion serving as the external connection terminal, the external connection terminal exposed on the back surface of the semiconductor package when individually cut is provided with a space over the edge. It has been proposed to provide a solder portion in a space portion so that a solder connection portion is visible from an external connection terminal exposed on a side surface of the semiconductor package.

  Further, for example, in the following Patent Document 2, a concave portion is provided on the back surface of a lead frame, and after a front surface side is resin-sealed, a predetermined region including the concave portion is subjected to half-cut processing from a sealing resin side, so that the concave portion is formed. By forming a through hole in the part where it was provided, and then performing full cut processing with a width smaller than the width of the half cut processing, the external connection terminal is projected to the side, solder It is described that a through hole or a slit is provided to make a connection portion visible.

JP 2000-294715 A JP 2011-124284 A

  However, in the technology described in Patent Document 1 in which a groove traversing the lead is formed at a cutting position of a terminal portion serving as an external connection terminal on the back surface side of the lead in the lead frame, the terminal portion is not sealed when resin is sealed. The resin may enter the groove, and a space for making the solder connection part visible may not be formed, and the yield of the semiconductor package product may be deteriorated.

  Further, in the technique described in Patent Document 2, after the resin sealing, two cutting steps of a half cut and a full cut using a blade are required, and the production efficiency is deteriorated. In addition, since the external connection terminals protrude sideways, it is disadvantageous for miniaturization of the semiconductor package.

  As described above, in a semiconductor package of a type in which a plurality of external connection terminals exposed on the back side are connected to an external device such as a printed circuit board, a conventional technology for making a solder connection portion visible is a semiconductor package. There were problems with product yield, production efficiency, and product miniaturization.

Therefore, the present inventors have repeated trial and error on a technique for making the solder connection portion that can solve these problems visible, and have improved the technique described in Patent Document 1 to improve the technique described in Patent Document 1 on the back side of the lead in the lead frame. A concave portion is formed at a position near the dam bar in the terminal portion serving as an external connection terminal and extends to a cutting area for cutting into individual lead frames, and after mounting a semiconductor element, sealing with resin, and cutting the individual semiconductor. When the package is manufactured, the edge of the external connection terminal exposed on the side surface of the semiconductor package is formed in a gate shape, and the soldered portion can be visually confirmed from a region surrounded by the gate-shaped edge. I thought about doing so and examined it.
However, in order to reduce the burden on the operator by visual inspection and to reduce the inspection time, soldering from the cut surface of the external connection terminal is required for the lead frame in which the concave portion is formed at the cutting position of the terminal portion serving as the external connection terminal. It was found that the amount of protrusion was required to be increased.

  In order to increase the amount of solder protruding from the cut surface of the external connection terminal, the inventor of the present invention increases the length of the concave portion formed in the terminal portion serving as the external connection terminal, and is held in the concave portion. We conceived a configuration to increase the amount of solder, and after further trial and error, when the amount of solder increased uniformly from the end on the cutting side to the end on the opposite side, when connecting to external equipment, It has been found that solder bleeding may occur on the opposite side and the external connection terminal may be short-circuited.

  The present invention has been made in view of the above-described conventional problems, and has a plurality of external connection terminals exposed on the back surface side, which can improve the yield of semiconductor package products, improve production efficiency, and can be reduced in size. Can be visually inspected for the good and bad solder connection status at the solder connection part in a semiconductor package of the type that connects the device to an external device such as a printed circuit board, and also reduces the burden on the operator and the inspection time due to the visual inspection. Provided is a lead frame and a method of manufacturing the same, which can easily increase the amount of solder protruding from the cut surface of the external connection terminal and can prevent short-circuit failure of the external connection terminal due to solder bleed. It is an object.

  In order to achieve the above object, a lead frame according to the present invention is provided with a plurality of external connection terminals exposed on a side surface and a side surface connected to an external device, and is a lead frame used for manufacturing a semiconductor package. The lead frame is connected to a dam bar and arranged in multiple rows, and a terminal portion serving as the external connection terminal on a surface of the lead frame connected to an external device is cut into individual lead frames near the dam bar. A concave portion having a predetermined opening shape is formed at a predetermined position extending inside the cutting region for performing the cutting, and the concave portion is arranged from the vicinity of the cutting region in the terminal portion serving as the external connection terminal to the side opposite to the cutting region. It is characterized in that it has a region where the depth decreases or the width decreases gradually or continuously.

  Further, in the lead frame according to the present invention, the concave portion may include a first region, the first region, and the first region, which are arranged in the order from the vicinity of the cutting region to the side opposite to the cutting region in the terminal portion serving as the external connection terminal. A second region connected to the first region, the depth of the second region is shallower than the depth of the first region, and the width of the second region is smaller than that of the first region. It is preferable that the width is equal to or less than the width, and the area of the second region in plan view is smaller than the area of the first region in plan view.

  Further, in the lead frame of the present invention, the recess has a third region between the first region and the second region, the third region being connected to the first region and the second region. The depth of the third region is smaller than any of the depth of the first region and the depth of the second region, and the width of the third region is smaller than that of the first region. The width of the third region is smaller than the width of the second region; and the width of the third region is smaller than the width of the second region. Is also preferably small.

  Further, the method for manufacturing a lead frame according to the present invention includes a plurality of external connection terminals that are exposed on the side and the side connected to the external device, and the individual lead frames are connected to a dam bar and arranged in multiple rows. A method of manufacturing a lead frame used for manufacturing a package, comprising: forming a first etching resist mask covering an entire surface on one surface of a metal plate; and forming the external connection on the other surface of the metal plate. A cutting area in the terminal section serving as the external connection terminal at a position corresponding to the terminal section serving as the terminal for use, and at a predetermined position near the dam bar and inside the cutting area for cutting into individual lead frames. First etching provided with an opening of a predetermined shape having an opening region whose width is reduced stepwise or continuously from the vicinity toward the side opposite to the cutting region. Forming a resist mask, half-etching is performed from the other surface side of the metal plate, and stepwise from near the cut region in the terminal portion serving as the external connection terminal to the side opposite to the cut region. Or a step of continuously forming a concave portion having a region where the depth becomes shallow or narrow, and a step of removing the first etching resist mask formed on the metal plate; Forming a second etching resist mask covering the dam bar, the terminal portion serving as the external connection terminal, and other positions corresponding to the leads constituting the lead frame, on both surfaces of the metal plate; Etching was performed from the surface side, and the individual lead frame areas were cut into individual lead frame areas, with the multi-row lead frame connected to the dam bar. A step of forming the cross-sectional shape of the terminal portion serving as the external connection terminal into a gate shape, and a step of removing the second etching resist mask formed on the metal plate. Features.

  In the method for manufacturing a lead frame according to the present invention, the opening of the predetermined shape in the step of forming the first etching resist mask is formed by cutting the portion from a vicinity of a cutting region in a terminal portion serving as the external connection terminal. A first opening region and a second opening region connected to the first opening region are arranged in the order opposite to the region, and the width of the second opening region is the first opening region. The width of the second opening region is smaller than the width of the region, and the area of the second opening region in plan view is smaller than the area of the first opening region in plan view. A first region and a second region connected to the first region in order from the vicinity of the cutting region to the side opposite to the cutting region in the terminal portion serving as the terminal for use, The depth of the region is the first region Shallower than the depth, the width of the second region is less than or equal to the width of the first region, and the area of the second region in plan view is smaller than the area of the first region in plan view. It is preferably smaller.

  ADVANTAGE OF THE INVENTION According to the present invention, the type of connecting a plurality of external connection terminals exposed on the back side to an external device such as a printed circuit board can improve the yield of semiconductor package products, improve the production efficiency, and cope with miniaturization. It is possible to visually inspect the good and bad of the solder connection state at the solder connection part in the semiconductor package of the above, and to reduce the burden on the worker by the visual inspection and the cutting time of the external connection terminal to the extent that the inspection time can be reduced. Thus, a lead frame and a method of manufacturing the lead frame can be obtained in which the amount of protruding solder can be easily increased, and short-circuit failure of external connection terminals due to solder bleed can be prevented.

FIGS. 2A and 2B are explanatory views showing a main part configuration of a lead frame according to the first embodiment of the present invention, wherein FIG. 2A is a view as seen from a side connected to an external device, and FIG. (C) is a cross-sectional view taken along line D-D of (b), (d) is a diagram showing another example of an opening shape in a concave portion applicable to the lead frame of the present invention, (e) ) Is an EE cross-sectional view of (d), (f) is a view showing still another example of an opening shape in a concave portion applicable to the lead frame of the present invention, and (g) is an FF cross-section of (f). Figures (h) is a view showing still another example of the opening shape in the concave portion applicable to the lead frame of the present invention, (i) is a GG sectional view of (h), and (j) is a lead of the present invention. FIG. 9 is a diagram showing still another example of the opening shape in the concave portion applicable to the frame, and (k) is a cross-sectional view taken along line HH of (j). FIG. 2 is a diagram illustrating an example of a state of a block in which the lead frames of FIG. 1A are arranged in multiple rows. FIG. 3 is an explanatory diagram showing an example of a state of a sheet in which a plurality of blocks of the lead frame of FIG. 2 are connected. FIG. 2 is an explanatory diagram illustrating an example of a manufacturing procedure of the lead frame of FIG. 1. FIG. 5 is an explanatory diagram showing an example of a procedure for manufacturing a semiconductor package using a lead frame manufactured by the manufacturing procedure of FIG. 4. FIG. 6E is a side view showing the state where the external connection terminals of the semiconductor package manufactured by the manufacturing procedure of FIG. 5 are soldered to an external device, as viewed from the same side as FIG. It is an explanatory view showing an example of the prior art for making the solder connection portion of the semiconductor package visible, (a) is a diagram viewed from the side of the lead frame used for the semiconductor package connected to external equipment, (b) is (a) (A) is a cross-sectional view taken along line AA of the semiconductor package assembled using the lead frame of ()), and (c) is a view showing a state where the external connection terminals of the semiconductor package of (b) are soldered to an external device. FIG. 3D is a cross-sectional view taken along the line BB showing a terminal portion serving as an external connection terminal in the lead frame of FIG. Explanatory drawing showing the configuration of a lead frame used in a semiconductor package in which the width of at least a part of the external connection terminals exposed on the side surface is different from that examined before deriving the present invention, and FIG. (B) is a cross-sectional view taken along line CC, showing a terminal portion serving as an external connection terminal in the lead frame of (a).

Prior to the description of the embodiment, the process of deriving the present invention and the operation and effect of the present invention will be described.
First, the inventor of the present invention has studied and considered a technique described in Patent Document 1 which is a conventional technique for making a solder connection portion of a semiconductor package visible.
The technique described in Patent Document 1 will be described with reference to FIG. 7A is a view of a lead frame used for a semiconductor package as viewed from the side connected to an external device, and FIG. 7B is a view AA of (a) in a semiconductor package assembled using the lead frame of (a). Sectional view, (c) is a sectional view showing a state in which the external connection terminal of the semiconductor package of (b) is soldered to an external device, and (d) is a terminal portion serving as an external connection terminal in the lead frame of (a). It is BB sectional drawing which shows this.

The lead frame used for the semiconductor package shown in FIG. 7A is located at a cutting position of a terminal portion 51 serving as an external connection terminal on the back surface side of the lead in the lead frame (a position on a dashed line in FIG. 7A). A groove 51b traversing the lead is formed. In FIG. 7A, reference numeral 52 denotes a pad for mounting a semiconductor element, and reference numeral 60 denotes a semiconductor element.
Then, the semiconductor element 60 is mounted on the pad portion 52 of the lead frame, and a terminal portion serving as an internal connection terminal of the lead on the side where the semiconductor element 60 is mounted is connected to the semiconductor element 60 by a bonding wire 61. By cutting the semiconductor package sealed in 70 along the cutting position, as shown in FIG. 7B, the external connection terminals 51 of the leads exposed on the back surface of the individually cut semiconductor package are cut. A space 51a is provided over the edge.
As shown in FIG. 7C, when the semiconductor package thus formed is soldered to the terminal 81 of the external device 80, the solder 90 is formed from the back surface of the external connection terminal 51 to the edge. Interposed in the space 51a. For this reason, the solder connection portion of the external connection terminal 51 exposed on the side surface of the semiconductor package can be visually confirmed, and the quality of the solder connection state of the semiconductor package with the external device 80 can be visually inspected.

However, as in the technique shown in FIG. 7, if a groove 51b is formed across the lead at the cutting position of the terminal portion serving as the external connection terminal 51 on the back side of the lead in the lead frame, the resin in the assembly of the semiconductor package can be reduced. At the time of sealing, the resin may enter the groove 51b of the terminal portion, and there is a possibility that the space portion 51a for making the solder connection portion visible is not formed.
That is, when a groove 51b crossing the lead is formed in the terminal portion 51 serving as an external connection terminal on the back surface side of the lead in the lead frame, the terminal portion 51 serving as the external connection terminal is located at the cutting position in FIG. As shown in (1), the width direction of the lead is formed to be thin throughout. Generally, when sealing the semiconductor element mounting side of the lead frame with a resin, a sheet-like tape is attached to the back surface of the lead frame to prevent the resin from entering the grooves on the back surface of the lead frame. However, in the technique shown in FIG. 7, since the surface outside the groove 51b along the width direction of the lead does not have a surface in close contact with the sheet-like tape, the outside portion of the groove 51b along the width direction of the lead is a sheet-like. Away from the tape. Here, even if the sheet-like tape is to be brought into close contact with the surface of the groove 51b, the sheet-like tape is greatly deformed, and it is difficult to make the sheet-like tape completely adhere to the groove 51b. A gap is easily formed between the surface and the surface. As a result, when the resin is sealed, the resin wraps around from the gap between the sheet-like tape and the surface of the groove 51b, the resin enters the groove 51b of the terminal portion 51, and the solder connection portion can be visually inspected. Since no space is formed, the yield of semiconductor package products may be reduced.

  Next, according to the technology described in Patent Document 2, as described above, after the resin sealing, two cutting steps of a half cut and a full cut are required using a blade, so that the production efficiency is deteriorated, and externally. Since the connection terminals are configured to protrude in the lateral direction, it is disadvantageous for downsizing the semiconductor package.

  Here, the inventor of the present invention has improved the technique described in Patent Document 1 to cut into individual lead frames in the vicinity of a dam bar in a terminal portion serving as an external connection terminal on the back side of a lead in a lead frame. An edge of an external connection terminal exposed on a side surface of a semiconductor package when a concave portion is formed at a position reaching a cutting area, and a semiconductor element is mounted, sealed with a resin, and cut to manufacture an individual semiconductor package. The part was formed in the shape of a gate, and the idea was conceived that the soldered portion could be visually confirmed from a region surrounded by the edge of the gate, and the study was conducted.

FIG. 8 is an explanatory view showing a configuration of a lead frame used in a semiconductor package in which at least a part of external connection terminals exposed on a side surface is different in width, which was studied in a stage before deriving the present invention. FIG. 2B is a view from the side of connection with the device, and FIG. 2B is a cross-sectional view taken along line CC, showing a terminal portion serving as an external connection terminal in the lead frame of FIG.
The lead frame shown in FIG. 8 has a terminal portion 11 serving as an external connection terminal at a predetermined position in the terminal portion 11 serving as an external connection terminal, which extends inside a cutting area for cutting into individual lead frames near the dam bar 13. A concave portion 11b 'having a predetermined opening shape is formed in accordance with the width of the portion 11 (the width of a region exposed by being cut at a position indicated by a broken line in FIG. 8A).
The recess 11b 'is surrounded by the terminal portion 11 serving as an external connection terminal and the dam bar 13. Then, in FIG. 8A, the cross-sectional shape of the external connection terminal 11 exposed to the side surface of the semiconductor package by being cut at the position of the broken line (that is, the end surface shape of the edge 11a 'of the external connection terminal 11) 8) is formed in a gate shape as shown in FIG. 8 (b).

The lead frame shown in FIG. 8 is different from the lead frame shown in FIG. 7 in that the periphery of the concave portion 11b 'is surrounded by a metal material constituting the terminal portion 11 or the dam bar 13 serving as an external connection terminal. The surface of the metal material surrounding the periphery of 11b 'is flat.
For this reason, the surface of the metal material around the concave portion 11b 'can be brought into close contact with the sheet-like tape, and when the semiconductor element mounting side of the lead frame is sealed with the resin, the resin enters the concave portion 11b'. Can be prevented.

  However, the present inventor has further studied and found that in the case of the configuration in which the concave portion 11b 'is formed at the cutting position of the terminal portion 11 serving as the external connection terminal as in the lead frame shown in FIG. In the end surface of the end portion 11a 'of the terminal 11, the area of the soldered portion on the cut surface of the external connection terminal 11 is reduced by the size of the surface of the metal material surrounding the recess 11b'. It has been found that if the amount of the solder protruding from the cut surface of the terminal 11 is small, the burden on the operator by the visual inspection and the inspection time increase.

In order to reduce the burden on the operator by visually inspecting the soldered portion on the cut surface of the external connection terminal 11 and the amount of time required for the inspection, the present inventor has determined that the amount of the solder protruding from the cut surface of the external connection terminal 11 can be reduced. In order to increase the number, the length of the concave portion 11b 'formed in the terminal portion serving as an external connection terminal was increased to increase the amount of solder held in the concave portion 11b'.
As a result, when the amount of solder increases uniformly from the end on the cutting side to the end on the opposite side (the center side of the inner rectangular area surrounded by the broken line in FIG. It has been found that, at the time of connection, solder bleed may occur on the side opposite to the cutting side, and the external connection terminal may be short-circuited.

More specifically, in the lead frame shown in FIG. 8, the concave portion 11b 'of the terminal portion 11 serving as an external connection terminal is formed from the cut end to the opposite side (the inner portion surrounded by a broken line in FIG. 8A). It is formed in a substantially rectangular parallelepiped opening shape having the same width and has the same depth toward the end portion (on the center side of the rectangular region). When soldering is performed on the concave portion 11b 'having such an opening shape, the solder is uniformly spread and held in the space region inside the concave portion 11b'.
When the amount of soldering to the concave portion 11b 'is increased, the amount of the solder is uniformly increased in the space area inside the concave portion 11b'.
For this reason, the solder amount to the concave portion 11b 'is increased so that the amount of solder protruding from the cut surface of the terminal portion serving as the external connection terminal is increased to the extent that the burden on the operator by the visual inspection and the inspection time can be reduced. In this case, the solder protrudes on the side opposite to the cut side in the concave portion 11b ', causing solder bleeding, and the external connection terminal is likely to cause a short circuit failure.

  However, from the customer who manufactures the semiconductor package, the amount of solder protrusion that can be visually inspected on the cut surface of the external connection terminal has been reduced in order to improve the workability of the visual inspection such as reducing the burden on the operator and the inspection time. It is required to increase.

  In order to solve this problem, the present inventor has conducted further trial and error, and has improved the yield of semiconductor package products, improved production efficiency, can respond to miniaturization, and has a plurality of external devices exposed on the back side. In a semiconductor package in which the connection terminal is connected to an external device such as a printed circuit board, it is possible to visually inspect the quality of the solder connection at the solder connection portion, and furthermore, the visual burden on the operator and the inspection time. The lead frame of the present invention, which can easily reduce the amount of solder protruding from the cut surface of the external connection terminal to the extent that can be reduced, and can prevent short-circuit failure of the external connection terminal due to solder bleeding, and the lead frame of the present invention. A manufacturing method has been derived.

  A lead frame according to the present invention is a lead frame used for manufacturing a semiconductor package, which includes a plurality of external connection terminals exposed on a side connected to an external device and a side surface, wherein each lead frame is connected to a dam bar. The terminal portion serving as an external connection terminal on the surface of the lead frame on the side connected to the external device has a predetermined portion extending in the vicinity of the dam bar and inside the cutting area for cutting into individual lead frames. A concave portion having a predetermined opening shape is formed at the position, and the concave portion has a depth gradually or continuously from the vicinity of the cutting region in the terminal portion serving as the external connection terminal toward the opposite side to the cutting region. It has an area that is shallower or narrower.

  Further, in the lead frame of the present invention, preferably, the concave portion includes the first region and the first region in order from the vicinity of the cutting region in the terminal portion serving as the external connection terminal to the side opposite to the cutting region. A second region connected to the region, wherein a depth of the second region is smaller than a depth of the first region, and a width of the second region is equal to or smaller than a width of the first region; Further, the area of the second region in plan view is formed in a predetermined shape that is smaller than the area of the first region in plan view.

Like the lead frame of the present invention, the terminal portion serving as an external connection terminal on the surface of the lead frame connected to the external device extends to the inside of the cutting area near the dam bar for cutting into individual lead frames. At a predetermined position, a concave portion having a predetermined opening shape is formed, and the concave portion has a depth, stepwise or continuously, from the vicinity of the cutting region in the terminal portion serving as the external connection terminal to the side opposite to the cutting region. When the solder is soldered to the concave portion, the solder does not uniformly spread over the space region inside the concave portion, and the depth in the concave portion is reduced. While it is easy to wet and spread in the vicinity of the cutting region that is relatively deep and relatively wide, it is difficult to wet and spread in the region opposite to the cutting region that is relatively shallow and relatively narrow in width.
As a result, when the semiconductor package manufactured by using the lead frame of the present invention is connected to an external device via solder, the solder in the space area inside the concave portion is biased and spreads to the vicinity of the cutting area, and the external connection The amount of protruding solder that can be visually inspected on the cut surface of the terminal can be increased, and solder bleed hardly occurs in a region opposite to the cut region, thereby preventing a short circuit failure of an external connection terminal. be able to.

Further, in the lead frame of the present invention, preferably, the recess has a third region connected to the first region and the second region between the first region and the second region. The depth of the third region is smaller than any of the depths of the first region and the second region, and the width of the third region is smaller than the width of the first region and the second region. Are formed in a predetermined shape that is smaller than any of the widths of the first region and the planar area of the third region is smaller than both the planar area of the first region and the planar region of the second region.
According to this configuration, the third region has a relatively large depth and a relatively large width in the concave portion, and a relatively small depth from the first region formed near the cutting region. It is possible to further suppress the spread of the solder to the second region which is shallow, has a relatively small width, and is formed on the semiconductor element mounting side opposite to the cutting region.

  Further, when the concave portion is formed in a region extending inside the cutting region in the terminal portion serving as the external connection terminal as in the lead frame of the present invention, the external connection terminal can be cut when cut into individual lead frame regions. Has a gate shape. For this reason, the solder connection portion when the semiconductor package is soldered to the external device can be visually confirmed from the gate-shaped end surface of the external connection terminal, and the solder connection state of the semiconductor package with the external device can be visually inspected. it can.

  In such a lead frame of the present invention, a first etching resist mask covering the entire surface is formed on one surface of a metal plate, and a terminal serving as an external connection terminal on the other surface of the metal plate is provided. A position corresponding to the portion, and at a predetermined position near the dam bar and inside the cutting region for cutting into individual lead frames, from the vicinity of the cutting region in the terminal portion serving as the external connection terminal to the cutting region, Forming a first etching resist mask provided with an opening of a predetermined shape having an opening region having a width gradually or continuously toward the side; and forming a half-width from the other surface side of the metal plate. Etching is performed, stepwise or continuously, from the vicinity of the cutting region to the side opposite to the cutting region in the terminal portion serving as the external connection terminal, the depth is reduced or the width is reduced. Forming a concave portion having a region, removing the first etching resist mask formed on the metal plate, forming a dam bar on both surfaces of the metal plate, a terminal portion serving as an external connection terminal, and other lead frames. Forming a second etching resist mask covering positions corresponding to the constituent leads; and performing multi-row leads in which individual lead frame regions are connected to dam bars by performing etching from both sides of the metal plate. Forming a frame so that the cross-sectional shape of a terminal portion serving as an external connection terminal when cut into individual lead frame regions has a gate shape; and forming the second etching resist formed on a metal plate. And a step of removing the mask.

  Therefore, according to the present invention, the yield and production efficiency of semiconductor package products are improved, miniaturization is possible, and a plurality of external connection terminals exposed on the back side are connected to external devices such as a printed circuit board. In the semiconductor package of the type, it is possible to visually inspect the quality of the solder connection at the solder connection part, and to cut off the external connection terminals to the extent that the visual inspection can reduce the burden on the worker and the inspection time. A lead frame and a method of manufacturing the lead frame can be obtained in which the amount of solder protruding from the surface can be easily increased, and short-circuit failure of external connection terminals due to solder bleed can be prevented.

  Hereinafter, an embodiment for carrying out the present invention will be described with reference to the drawings.

First Embodiment FIG. 1 is an explanatory view showing a main part configuration of a lead frame according to a first embodiment of the present invention. FIG. 1 (a) is a diagram viewed from a side connected to an external device, and FIG. The figure which shows an example of the opening shape in the recessed part formed in a lead frame, (c) is DD sectional drawing of (b), (d) is another opening shape in the recessed part applicable to the lead frame of this invention. (E) is a cross-sectional view taken along the line EE of (d), (f) is a diagram showing still another example of the opening shape in the concave portion applicable to the lead frame of the present invention, (g) is ( (f) is a sectional view taken along line FF, (h) is a diagram showing still another example of the opening shape in the concave portion applicable to the lead frame of the present invention, (i) is a sectional view taken along line GG of (h), (j) is a diagram showing still another example of the opening shape in the concave portion applicable to the lead frame of the present invention, and (k) is a sectional view taken along the line HH of (j). FIG. 2 is a diagram showing an example of a state of a block in which the lead frames of FIG. 1A are arranged in multiple rows. FIG. 3 is an explanatory diagram showing an example of a state of a sheet in which a plurality of blocks of the lead frame of FIG. 2 are connected. FIG. 4 is an explanatory diagram showing an example of a manufacturing procedure of the lead frame of FIG. FIG. 5 is an explanatory view showing an example of a manufacturing procedure of a semiconductor package using the lead frame manufactured by the manufacturing procedure of FIG.

The lead frame 1 according to the first embodiment is a lead frame used for manufacturing a semiconductor package and provided with a plurality of external connection terminals exposed on the side and the side connected to an external device. Are connected to the dam bar 13 and are arranged in multiple rows, and are formed as a multiple-row type lead frame as shown in FIGS.
As shown in FIG. 1A, each lead frame 1 has a terminal portion 11 serving as an external connection terminal on a surface of the lead frame 1 connected to an external device. A concave portion 11b having a predetermined opening shape is formed at a predetermined position extending inside a cutting region for cutting into a frame.
In the present embodiment, each of the lead frames 1 adjacent to the dam bar 13 between the terminal portions 11 serving as external connection terminals on the surface of the lead frame 1 adjacent to the dam bar 13 on the side connected to the external device is provided. In this embodiment, concave portions 11b are formed at predetermined positions extending inside a cutting region for cutting.
The concave portion 11b extends from the vicinity of the cutting region in the terminal portion 11 serving as the external connection terminal to the opposite side to the cutting region (the center side of the inner rectangular region surrounded by the broken line in FIG. 1A). It is formed stepwise or continuously with a region where the depth is reduced and the width is reduced.
More specifically, for example, as shown in FIGS. 1B and 1C, the concave portion 11 b is formed from the vicinity of the cut region in the terminal portion 11 serving as the external connection terminal toward the side opposite to the cut region. In order, it has a first region 11b-1 and a second region 11b-2 connected to the first region 11b-1.
Each of the first region 11b-1 and the second region 11b-2 has a rectangular opening shape.
The depth of the second region 11b-2 is smaller than the depth of the first region 11b-1.
The width of the second region 11b-2 is smaller than the width of the first region 11b-1.
Further, the area of the second region 11b-2 in plan view is smaller than the area of the first region 11b-1 in plan view.
In addition, in addition to the examples shown in FIGS. 1B and 1C, the recesses 11b are, for example, FIG. 1D and FIG. 1E, FIG. 1F, FIG. 1 (h) and 1 (i), and FIG. 1 (j) and FIG. 1 (k).

In the example shown in FIG. 1D and FIG. 1E, the concave portion 11b is provided between the first region 11b-1 and the second region 11b-2 and between the first region 11b-1 and the second region 11b-2. And a third region 11b-3 connected to the region 11b-2.
The third region 11b-3 has a rectangular opening shape.
The depth of the third region 11b-3 is smaller than both the depth of the first region 11b-1 and the depth of the second region 11b-2.
The width of the third region 11b-3 is smaller than both the width of the first region 11b-1 and the width of the second region 11b-2.
The planar area of the third region 11b-3 is smaller than both the planar area of the first region 11b-1 and the planar area of the second region 11b-2.
Others are substantially the same as the examples shown in FIGS. 1B and 1C.

In the example shown in FIG. 1F and FIG. 1G, the opening of the second region 11b-2 of the recess 11b is formed in a triangular shape.
At the connection position of the second region 11b-2 with the first region 11b-1, the depth and the width are the same as those of the first region 11b.
The second region 11b-2 continuously decreases in depth and slopes from the connection position with the first region 11b-1 toward the opposite side to the first region 11b-1. And the width has been reduced.
Others are substantially the same as the examples shown in FIGS. 1B and 1C.

In the example shown in FIGS. 1H and 1I, the opening of the second region 11b-2 of the recess 11b is formed in an elliptical shape.
The second region 11b-2 continuously decreases in depth and curves from the connection position with the first region 11b-1 toward the opposite side to the first region 11b-1. .
Others are substantially the same as the examples shown in FIGS. 1 (f) and 1 (g).

  In the example shown in FIGS. 1 (j) and 1 (k), the concave portion 11b has a trapezoidal opening shape in the entire region, and is formed from the vicinity of the cutting region in the terminal portion 11 serving as an external connection terminal to the cutting region. , As it goes to the opposite side, the depth becomes shallower and slopes continuously and becomes narrower.

Next, an example of a manufacturing process of the lead frame of the present embodiment will be described with reference to FIG. In FIG. 4, for convenience of description, a side mainly connected to an external device is shown, and a side on which a semiconductor element is mounted is partially omitted.
First, a copper or copper alloy metal plate 10 is prepared as a lead frame material (see FIG. 4A).
Next, the concave portion 11b is formed by subjecting the metal plate 10 to a half-etching process. Specifically, a first resist layer R1 such as a dry film resist is formed on both surfaces of the metal plate 10 (see FIG. 4B). Next, the first resist layer R1 on one side of the metal plate 10 is exposed, and the first resist layer R1 on the other surface of the metal plate 10 is located at a position corresponding to a terminal portion serving as an external connection terminal. 1 (b), FIG. 1 (d), FIG. 1 (f), FIG. 1 (g) or FIG. 1 (h) at a predetermined position extending inside the cutting area for cutting into a lead frame. A pattern corresponding to a predetermined opening shape having a region where the width becomes narrower was drawn stepwise or continuously from the vicinity of the cutting region to the side opposite to the cutting region in the terminal portion serving as the external connection terminal. Using a glass mask, the first resist layer R1 on the other side of the metal plate 10 is exposed and developed to form a first etching resist mask 31 (see FIG. 4C). Next, a half-etching process is performed using an etching solution to form a concave portion 11b on the other side of the metal plate 10 (see FIG. 4D). At this time, the depth of the concave portion 11b formed by performing the half-etching process becomes a depth corresponding to the width at each position in the opening formed in the first etching resist mask 31 (for example, In a relatively narrow region or position, the depth is shallow, and in a relatively wide region or position, the depth is deep.) Next, the first etching resist mask 31 is removed (see FIG. 4E).

Next, the surface of the terminal portion serving as the internal connection terminal, the surface of the terminal portion serving as the external connection terminal, and the surface of the concave portion formed inside the terminal portion serving as the external connection terminal in the lead frame, Plating to improve wettability. Specifically, a second resist layer R2 such as a dry film resist is formed on both surfaces of the metal plate 10 (see FIG. 4F). Next, the second resist layer R2 on both sides of the metal plate 10 is exposed using a glass mask on which a pattern corresponding to a terminal portion serving as an external connection terminal and a terminal portion serving as an internal connection terminal is drawn, and developed. Then, a plating resist mask 32 is formed which covers portions corresponding to the terminal portions serving as external connection terminals and the terminal portions serving as internal connection terminals, and exposes other portions (see FIG. 4 (g)). Next, plating is performed on the portion exposed from the plating resist mask 32 in the order of, for example, Ni, Pd, and Au (see FIG. 4H). As a result, a Ni / Pd / Au plating layer (not shown) is formed on the surface of the terminal portion serving as an internal connection terminal (not shown), and Ni / Pd / Au is formed on the surface of the terminal serving as an external connection terminal and the surface of the concave portion. An Au plating layer 12 is formed.
The surface of the plating layer is preferably subjected to a roughening treatment. When the surface of the plating layer is roughened, for example, the formation of the plating layer may be finished by Ni plating, and the Ni plating layer may be formed by rough plating. Further, for example, after forming a smooth Ni plating layer, the surface of the Ni plating layer may be roughened by etching. Further, for example, the formation of the plating layer may be finished by Cu plating, and the surface of the Cu plating layer may be roughened by anodizing or etching. Further, for example, a Pd / Au plating layer may be sequentially stacked after forming the roughened plating layer.
Next, the plating resist mask 32 is peeled off (see FIG. 4 (i)).

Next, the metal plate 10 is subjected to etching to form a multi-row lead frame in which individual lead frame regions are connected to dam bars. Specifically, a third resist layer R3 such as a dry film resist is formed on both surfaces of the metal plate (see FIG. 4 (j)). Next, using a glass mask on which a pattern corresponding to the dam bar, the terminal portion serving as an external connection terminal, the terminal portion serving as an internal connection terminal, and other leads constituting the lead frame is drawn, the second portion on both sides of the metal plate 10 is drawn. The resist layer R3 of No. 3 is exposed and developed to cover a dam bar, a terminal portion serving as an external connection terminal, a terminal portion serving as an internal connection terminal, and other portions corresponding to the leads constituting the lead frame. A second etching resist mask 33 exposing the portion is formed (see FIG. 4K). Next, etching is performed from both sides of the metal plate 10 to connect the multi-row type lead frame in which the regions of the individual lead frames 1 are connected to the dam bars to the external connection when the regions of the individual lead frames 1 are cut. The cross-sectional shape of the terminal portion 11 serving as a terminal for use is formed so as to have a gate shape (see FIG. 4 (l)). Next, the second etching resist mask 33 formed on the metal plate 10 is removed (see FIG. 4 (m)).
Thereby, the lead frame 1 of the present embodiment is completed.

In addition, the step of performing plating (see FIGS. 4 (f) to 4 (i)) for improving the wettability at the time of solder connection includes the surface of the terminal portion serving as the external connection terminal and the external connection. It is also possible to omit the surface of the concave portion formed inside the terminal portion serving as the terminal for use.
Further, when forming the lead frame 1 by performing an etching process, a half-etching process may be performed on an intermediate portion of the lead and other necessary portions.

Next, a manufacturing procedure of the semiconductor device using the lead frame of the present embodiment will be described with reference to FIG. Note that, for convenience of explanation, a terminal portion, a solder ball, and a semiconductor element, which are internal connection terminals on the semiconductor element mounting side, which will be described later, are not illustrated.
First, a semiconductor element is flip-chip connected to a terminal portion serving as a predetermined internal connection terminal via a solder ball or the like (not shown).
Next, a sheet-shaped masking tape m1 is attached to the connection side with the external device (see FIG. 5A), a mold (not shown) is set, and the semiconductor element mounting side is sealed with the resin 21 (FIG. 5 (b)), at this time, the recess 11b is surrounded by the terminal portion 11 serving as an external connection terminal and the dam bar 13 (here, the dam bar 13 located on the lower side in FIG. 1 (a)). The terminal portion 11 and the dam bar 13 serving as external connection terminals on the back surface are in close contact with the sheet-shaped masking tape m1, and the inside of the concave portion 11b is sealed. Therefore, when forming the sealing resin, the resin 21 does not enter the concave portion 11b, and the concave portion 11b is finished in an exposed state similarly to the terminal portion 11 serving as the external connection terminal on the back surface side.
Next, the masking tape m1 is removed (see FIG. 5C), and cut into predetermined dimensions of the semiconductor device 40 (see FIG. 5D). Thus, the semiconductor device 40 using the lead frame of the present embodiment shown in FIG. 1 is completed (see FIG. 5E).

According to the lead frame of the first embodiment, the terminal portion 11 serving as an external connection terminal on the surface of the lead frame 1 on the side to be connected to the external device is cut in the vicinity of the dam bar 13 for cutting into individual lead frames. A concave portion 11b having a predetermined opening shape is formed at a predetermined position extending inside the region, and the concave portion 11b is formed in a step shape from the vicinity of the cut region in the terminal portion 11 serving as an external connection terminal to the side opposite to the cut region. Target or continuously, it is configured to have a region where the depth becomes shallow and the width becomes narrow, so that when soldering to the concave portion 11b, the solder is uniformly applied to the space region inside the concave portion 11b. It does not spread and spreads easily in the vicinity of the cut region where the depth is relatively deep and relatively wide in the concave portion 11b, but is opposite to the cut region where the depth is relatively shallow and the width is relatively narrow. ~ side Hardly wets the area of the semiconductor element mounting side.
As a result, when the semiconductor package 40 manufactured using the lead frame of the present embodiment is connected to an external device via solder, the solder in the space area inside the concave portion 11b is unbalanced and spreads near the cutting area, The amount of protruding solder that can be visually inspected on the cut surface of the external connection terminal 11 can be increased, and solder bleed hardly occurs in a region opposite to the cut region, and short-circuiting of the external connection terminal occurs. Defects can be prevented.

  Further, in the lead frame of the present embodiment, as shown in FIGS. 1D and 1E, the recess 11b is formed between the first region 11b-1 and the second region 11b-2. , A third region 11b-3 connected to the first region 11b-1 and the second region 11b-2, and the depth of the third region 11b-3 is smaller than that of the first region 11b-1. The width of the third region 11b-3 is smaller than both the depth and the depth of the second region 11b-2, and is smaller than the width of the first region 11b-1 and the width of the second region 11b-2. A predetermined shape that is narrower than any of them and the area of the third region 11b-3 in plan view is smaller than any of the area of the first region 11b-1 in plan view and the area of the second region 11b-2 in plan view. According to the configuration formed in the concave portion 11b-3, the depth is relatively large and the width is relatively large in the concave portion 11b due to the third region 11b-3. From the first region 11b-1 formed in the vicinity of the cut region, the depth is relatively shallow, the width is relatively small, and the second region is formed on the semiconductor element mounting side opposite to the cut region. 2 can further suppress the spread of the solder to the region 11b-2.

  Further, according to the lead frame of the present embodiment, since the concave portion 11b in the terminal portion 11 serving as the external connection terminal is formed in a region extending inside the cutting region, when the individual lead frame 1 is cut, The cross-sectional shape of the external connection terminal 11 is a gate shape. For this reason, as shown in FIG. 6, when the external connection terminal 11 of the semiconductor package 40 is soldered to the terminal 81 of the external device 80, the connection state of the solder 90 is changed to the gate-shaped edge of the external connection terminal. It can be visually confirmed from the side of 11a, and a good or bad solder connection state between the semiconductor package and an external device can be visually inspected.

  Therefore, according to the present embodiment, the yield of the semiconductor package product, the production efficiency is improved, the size can be reduced, and the plurality of external connection terminals exposed on the back side can be connected to external devices such as a printed circuit board. In the semiconductor package of the connection type, the quality of the solder connection at the solder connection portion can be visually inspected for good or bad, and the load of the operator by the visual inspection and the inspection time can be reduced to the extent that the external connection terminals can be reduced. A lead frame and a method of manufacturing the lead frame can be obtained in which the amount of protruding solder from the cut surface can be easily increased, and short-circuit failure of external connection terminals due to solder bleed can be prevented.

Next, examples of the lead frame of the present invention and the method of manufacturing the same will be described.
Example 1
First, a copper-based material having a thickness of 0.2 mm was prepared as the metal plate 10 (see FIG. 4A), and a dry film resist was laminated on both surfaces as the first resist layer R1 (FIG. 4B). reference).
Next, while exposing the first resist layer R1 on one side of the metal plate 10, a glass mask on which a pattern corresponding to the opening shape shown in FIGS. 1A to 1C is drawn is used. The other surface is exposed to light, developed, covered on one surface, and cut into individual lead frames at positions corresponding to terminal portions serving as external connection terminals on the other surface, near dam bars. A first opening region (not shown) from the vicinity of the cutting region in the terminal portion serving as the external connection terminal to the side opposite to the cutting region, at a predetermined position extending inside the cutting region for A first etching resist mask 31 having an opening of a predetermined shape connected to a second opening region (not shown) having a smaller width and a smaller area than that of the first opening and covering other regions was formed (FIG. 4 (c)).
Note that the width of the first opening region is about 80% of the width of the terminal portion serving as the external connection terminal, and the width of the second opening region is about 40% of the width of the terminal portion serving as the external connection terminal. did. Further, the length of the first opening region and the length of the second opening region are made approximately equal, and the area of the second opening region in plan view is about 50% of the area of the first opening region in plan view. .
Next, a half-etching process with a depth of 0.150 mm was performed from the other surface side of the metal plate 10 to form a concave portion 11b on the other side of the metal plate 10 (see FIG. 4D). At this time, the depth of the first region corresponding to the first opening region in the concave portion 11b formed by the half etching process is 0.130 mm, and the depth of the second region corresponding to the second opening region. Became 0.080 mm. The etching solution used was a ferric chloride solution.
Next, the first etching resist mask 31 was removed (see FIG. 4E).

Next, a dry film resist was laminated on both surfaces of the metal plate 10 as a second resist layer R2 (see FIG. 4 (f)).
Next, both sides are exposed and developed using a glass mask on which a predetermined pattern corresponding to the lead frame shown in FIGS. 1A to 1C is drawn, and developed to become external connection terminals. A plating resist mask 32 was formed to cover the portions corresponding to the terminal portions and the terminal portions serving as the internal connection terminals, and to expose the other portions (see FIG. 4 (g)). Next, the portion exposed from the plating resist mask 32 was sequentially plated with Ni to a thickness of 1.0 μm, Pd to a thickness of 0.03 μm, and Au to a thickness of 0.01 μm to form a plating layer 11 (FIG. 4 ( h)).
Next, the plating resist mask 32 was removed (see FIG. 4 (i)).

Next, a dry film resist was laminated as a third resist layer R3 on both surfaces of the metal plate 10 (see FIG. 4 (j)).
Next, both sides are exposed and developed using a glass mask on which a predetermined pattern corresponding to the lead frame shown in FIGS. 1A to 1C is drawn, developed, and a dam bar and an external connection terminal are formed. A second etching resist mask 33 is formed, which covers the terminal portions serving as the internal connection terminals, the terminal portions serving as the internal connection terminals, and other portions corresponding to the leads constituting the lead frame, and exposing the other portions (FIG. 4). (k)).
Next, an etching process is performed from both sides of the metal plate 10 to cut the multi-row type lead frame in which the region of each lead frame 1 is connected to the dam bar 13 into the region of each lead frame 1. The terminal section serving as the external connection terminal was formed so that the cross-sectional shape was a gate shape (see FIG. 4 (l)). The etching solution used was a ferric chloride solution.
Next, the second etching resist mask 33 formed on the metal plate 10 was removed (see FIG. 4 (m)).
Thus, the lead frame 1 of Example 1 was obtained.

  Next, the semiconductor element is flip-chip connected to a predetermined internal terminal connection portion via a solder ball or the like (not shown), and a polyimide mask with a heat-resistant adhesive is formed as a sheet-shaped masking tape m1 on the connection side with an external device. A film was attached (see FIG. 5A), a mold (not shown) was set, and the semiconductor element mounting side was sealed with a resin 21 (see FIG. 5B).

At this time, the concave portion 11b is surrounded by the terminal portion 11 serving as an external connection terminal and the dam bar 13, and the terminal portion 11 serving as the external connection terminal and the dam bar 13 on the back side adhere to the sheet, and the concave portion 11b Is sealed, so that when the sealing resin is formed, the concave portion 11b is finished in a state where the resin 21 is exposed without penetrating similarly to the terminal portion 11 serving as the external connection terminal on the back surface side.
Next, the masking tape m1 was removed (see FIG. 5 (c)), and cut into predetermined dimensions of the semiconductor package 40 (see FIG. 5 (d)). Thus, a semiconductor package 40 manufactured using the lead frame 1 of Example 1 was obtained (see FIG. 5E).

Example 2
First, a copper-based material having a thickness of 0.2 mm was prepared as the metal plate 10 (see FIG. 4A), and a dry film resist was laminated on both surfaces as the first resist layer R1 (FIG. 4B). reference).
Next, while exposing the first resist layer R1 on one side of the metal plate 10, a glass mask on which a pattern corresponding to the opening shape shown in FIGS. 1D and 1E is drawn is used. The other surface is exposed to light, developed, covered on one surface, and cut into individual lead frames at positions corresponding to terminal portions serving as external connection terminals on the other surface, near dam bars. A first opening region (not shown) and a second opening region (not shown) extending from the vicinity of the cutting region in the terminal portion serving as the external connection terminal to the opposite side to the cutting region at predetermined positions extending inside the cutting region for the external connection. A third opening region (not shown) connected to the first opening region and the second opening region between the first opening region and the first opening region. A plane view of the third opening region, which is smaller than either the width or the width of the second opening region; Form a first etching resist mask 31 having an opening of a predetermined shape smaller than either the planar area of the first opening region or the planar area of the second opening region, and covering the other regions. (See FIG. 4 (c)).
Note that the width of the first opening region is about 80% of the width of the terminal portion serving as the external connection terminal, the width of the second opening region is about 40% of the width of the terminal portion serving as the external connection terminal, The width of the third opening region was about 90% of the width of the second opening region. In addition, the length of the first opening region and the length of the second opening region are made approximately equal, and the length of the third opening region is made approximately 25% of the length of the first opening region. The area of the area in plan view is about 50% of the area of the first opening area in plan view, the area of the third opening area in plan view is about 10% of the area of the first opening area in plan view, and the second opening area. The area was set to about 20% of the area of the region in plan view.

Next, a half-etching process with a depth of 0.150 mm was performed from the other surface side of the metal plate 10 to form a concave portion 11b on the other side of the metal plate 10 (see FIG. 4D). At this time, the depth of the first region corresponding to the first opening region in the concave portion 11b formed by the half etching process is 0.130 mm, and the depth of the third region corresponding to the third opening region. Was 0.030 mm, and the depth of the second region corresponding to the second opening region was 0.080 mm. The etching solution used was a ferric chloride solution.
Next, the first etching resist mask 31 was removed (see FIG. 4E).
Thereafter, the lead frame 1 of the second embodiment was obtained by substantially the same procedure and method as in the first embodiment (see FIGS. 4 (f) to 4 (m)).

  Next, a semiconductor package 40 manufactured using the lead frame 1 of the second embodiment was obtained by the same procedure and method as in the first embodiment (see FIGS. 5A to 5E).

Comparative Example 1
First, a copper-based material having a thickness of 0.2 mm was prepared as the metal plate 10 (see FIG. 4A), and a dry film resist was laminated on both surfaces as the first resist layer R1 (FIG. 4B). reference).
Next, while exposing the first resist layer R1 on one side of the metal plate 10, a glass mask on which a pattern corresponding to the opening shape shown in FIGS. 8A and 8B is drawn is used. The other surface is exposed and developed to cover one surface and cut into individual lead frames near the dam bar at positions corresponding to the terminal portions for external connection terminals on the other surface. A rectangular opening extending at the same width from the position of the cut surface toward the semiconductor element mounting side (the center side in FIG. 8) at a predetermined position extending inside the cutting region for covering the other region. Then, a first etching resist mask 31 was formed, and a half-etching process with a depth of 0.150 mm was performed from the other surface side of the metal plate 10 to form a concave portion 11b 'having the same depth in all regions. . Other than that, the lead frame 1 of Comparative Example 1 was manufactured in substantially the same content and procedure as in Example 1.
The width of the opening in the first etching resist mask 31 was about 80% of the width of the terminal portion serving as an external connection terminal.
The depth of the concave portion formed by the half-etching process was 0.130 mm over the entire region.

  Next, a semiconductor package 40 manufactured using the lead frame 1 of Comparative Example 1 was obtained by the same procedure and method as in Example 1 (see FIGS. 5A to 5E).

Evaluation of presence or absence of short-circuit failure of external connection terminals due to solder bleed Examples 1 and 2 and Comparative Example 1 were used as test samples of the semiconductor package 40 manufactured using the lead frames 1 of Examples 1 and 2 and Comparative Example 1, respectively. Each of the lead frames 1 is provided with 1000 empty packages prepared by sealing with resin without intentionally incorporating a semiconductor element, and the external connection terminals 11 of each empty package are connected to the terminals of the printed circuit board 80. 81, the solder is sufficiently removed from the cut surface of the external connection terminal 11 in which the edge portion 11a is formed in a gate shape so that the solder can sufficiently protrude from the cut surface of the external connection terminal 11 to the extent that the burden on the operator and the inspection time can be reduced. The solder was connected to the printed circuit board while adjusting the amount, and the printed circuit board was inspected for short-circuit failure of the external connection terminal due to solder bleed.

The inspection was performed by measuring the insulation resistance with an insulation tester.
As a test sample, an empty package manufactured by sealing with a resin without incorporating a semiconductor element is in a state where external connection terminals are electrically insulated. For this reason, when the external connection terminal of the empty package is soldered to the terminal of the printed circuit board and no solder bleed occurs at the external connection terminal, a predetermined value or more indicating that the external connection terminal is insulated. Is obtained. On the other hand, when solder bleed occurs at one of the external connection terminals provided in the empty package and is electrically connected to the adjacent external connection terminal, an insulation resistance value less than a predetermined value indicating insulation failure is obtained. can get.
As a result, in the empty package of the test sample using each of the lead frames of the first and second embodiments, the external connection terminal by solder bleed in a state where the external connection terminal 11 is soldered to the terminal 81 of the printed circuit board 80. Had no short-circuit failure.
On the other hand, in the empty package of the test sample using each of the lead frames of Comparative Example 1, the external connection terminals 11 were soldered to the external connection terminals 11 in a state where the external connection terminals 11 were soldered to the terminals 81 of the printed circuit board 80. Sixteen short-circuit defects (incidence rate: 1.6%) occurred.

  The preferred embodiments and examples of the present invention have been described above in detail, but the present invention is not limited to the above-described embodiments and examples, and does not depart from the scope of the present invention. Various modifications and substitutions can be made to the embodiment.

  INDUSTRIAL APPLICABILITY The lead frame and the method of manufacturing the same according to the present invention are useful in a field where it is required to be used for a semiconductor package of a type in which an external connection terminal on the back side is connected to a printed board or the like.

DESCRIPTION OF SYMBOLS 1 Lead frame 10 Metal plate 11, 51 Terminal part used as an external connection terminal (or external connection terminal)
11a Gate-shaped edge 11b, 11b 'Recess 11b-1 First area 11b-2 Second area 11b-3 Third area 12 Plating layer 13 Dam bar 20, 60 Semiconductor element 21, 70 Sealing resin 31 First etching resist mask 32 Plating resist mask 33 Second etching resist mask 40 Semiconductor package 51a Space 51b Groove 52 Pad 80 External equipment 81 Terminal 90 Solder m1 Masking tape R1 First resist layer R2 Second Resist layer R3 Third resist layer

Claims (5)

A lead frame used for manufacturing a semiconductor package, comprising a plurality of external connection terminals exposed on a surface and a side surface connected to an external device,
Individual lead frames are connected to the dam bar and arranged in multiple rows,
A terminal portion serving as the external connection terminal on the surface of the lead frame connected to the external device has a predetermined position in the vicinity of the dam bar at a predetermined position extending inside a cutting area for cutting into individual lead frames. A concave portion having an opening shape is formed,
The recess has a region where the depth becomes shallow or narrow in a stepwise or continuous manner from the vicinity of the cutting region in the terminal portion serving as the external connection terminal to the side opposite to the cutting region. A lead frame characterized in that: The recess has a first region and a second region connected to the first region in order from the vicinity of the cutting region in the terminal portion serving as the external connection terminal to the side opposite to the cutting region. And
A depth of the second region is smaller than a depth of the first region,
A width of the second region is equal to or smaller than a width of the first region; and
2. The lead frame according to claim 1, wherein a plan view area of the second region is smaller than a plan view area of the first region. 3. The recess has a third region connected to the first region and the second region between the first region and the second region,
A depth of the third region is smaller than a depth of the first region or a depth of the second region;
The width of the third region is smaller than any of the width of the first region and the width of the second region, and
3. The lead frame according to claim 2, wherein a plan view area of the third region is smaller than any of a plan view area of the first region and a plan view area of the second region. 4. A method for manufacturing a lead frame used for manufacturing a semiconductor package, comprising a plurality of external connection terminals exposed on a surface and a side surface on a side to be connected to an external device, wherein individual lead frames are connected to a dam bar and arranged in multiple rows. So,
Forming a first etching resist mask covering the entire surface on one surface of the metal plate, and a position corresponding to a terminal portion serving as the external connection terminal on the other surface of the metal plate, At a predetermined position in the vicinity of the dam bar and inside the cutting area for cutting into individual lead frames, stepwise from the vicinity of the cutting area in the terminal portion serving as the external connection terminal toward the opposite side to the cutting area. Or continuously, forming a first etching resist mask provided with an opening of a predetermined shape having an opening region having a reduced width;
Half-etching is performed from the other surface side of the metal plate, and the depth is shallower in a stepwise or continuous manner from the vicinity of the cutting region in the terminal portion serving as the external connection terminal to the side opposite to the cutting region. Forming a recess having a region that becomes or becomes narrower,
Removing the first etching resist mask formed on the metal plate;
A step of forming a second etching resist mask covering positions corresponding to the leads corresponding to the leads constituting the dam bar, the external connection terminals, and other lead frames on both surfaces of the metal plate;
Etching is performed from both sides of the metal plate, and the multi-row type lead frame in which each lead frame region is connected to the dam bar becomes the external connection terminal when cut into individual lead frame regions. A step of forming the cross-sectional shape of the terminal portion to be a gate shape,
Removing the second etching resist mask formed on the metal plate;
A method for manufacturing a lead frame, comprising: The opening having the predetermined shape in the step of forming the first etching resist mask is formed in the order from the vicinity of the cutting region in the terminal portion serving as the external connection terminal to the opposite side to the cutting region in the order of the first opening. And a second opening region connected to the first opening region, wherein the width of the second opening region is equal to or less than the width of the first opening region, and The area of the opening region in plan view is smaller than the area of the first opening region in plan view,
The concave portion in the step of forming the concave portion includes a first region and a first region in order from the vicinity of the cut region in the terminal portion serving as the external connection terminal to the side opposite to the cut region. A second region connected thereto, wherein a depth of the second region is smaller than a depth of the first region, and a width of the second region is equal to or less than a width of the first region. 5. The method according to claim 4, wherein the area of the second region in plan view is smaller than the area of the first region in plan view. 6.

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