JP7311226B2 - 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, however, in a semiconductor package of, for example, a QFN (Quad-Flat No-leaded) type that does not have an outer lead on the outer periphery, terminals for external connection are arranged on the back side of the semiconductor package and exposed on the back side of the semiconductor package. It is difficult to visually inspect whether the solder connection is normal or not, because the structure is such that a plurality of external connection terminals connected to the external connection are connected to an external device such as a printed circuit board.

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 the quality of the solder connection state in the solder connection part of the QFN type semiconductor package, for example, the following patent document 1 discloses the back surface side of the lead in the lead frame. By forming a groove across the lead at the cut position of the terminal part that will be the external connection terminal, the external connection terminal exposed on the back surface of the semiconductor package when cut individually has a space extending to the edge It has been proposed to provide a portion and allow solder to intervene 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, for example, in the following Patent Document 2, a concave portion is provided on the back surface of a lead frame, and after the surface side is sealed with resin, a predetermined region including the concave portion is subjected to half-cut processing from the sealing resin side, thereby forming the concave portion. A through-hole is formed in the previously provided part, and then a full-cut process is performed with a width narrower than the width of the half-cut process, so that the external connection terminal protrudes laterally, and solder is applied to the protruded part on the side. It is described that a through hole or a slit is provided to make the connection part visible.

Japanese Patent Application Laid-Open No. 2000-294715 JP 2011-124284 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.

In addition, the technique described in Patent Document 2 requires two cutting steps, half-cutting and full-cutting, using a blade after resin sealing, resulting in poor production efficiency. In addition, since the external connection terminal protrudes sideways, it is disadvantageous in reducing the size 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, conventional techniques for making the solder connection portions visible include: There were problems in terms of product yield, production efficiency, and product miniaturization.

Therefore, the inventors of the present invention repeated trial and error on a technique for making the soldered connection part visible, which can solve these problems, and improved the technique described in Patent Document 1, the back side of the lead in the lead frame. In the terminal part that will be the external connection terminal, a recess is formed near the dam bar at a position that extends to the cutting area for cutting into individual semiconductor packages. When the semiconductor package is manufactured, the edges of the external connection terminals exposed on the side surface of the semiconductor package are formed into a gate shape, and the soldered portion is visually confirmed from the area surrounded by the gate-shaped edge. I came up with the idea of making it possible and studied it.

Further, in the process of investigation by the present inventors, in this type of lead frame, there are problems in the adhesion of the leads having external connection terminals to the resin, and in the life of the blade that cuts into individual semiconductor packages. It has been found.

In recent years, miniaturization of semiconductor packages has been demanded, and in order to facilitate visual inspection of the soldered joints, the width and height of the portion of the lead frame where the soldered joints can be visually observed have been increased as much as possible. is desired.

Therefore, the inventors of the present invention visually inspected the solder connection part that can solve the above problems, including the problem of the adhesion of the lead having the terminal for external connection to the resin and the life of the blade that cuts into individual semiconductor packages. As a result of further trial and error with regard to the technology to make this possible, in order to make it easier to visually inspect the soldered connection part, the width and height of the part where the soldered connection part can be visually observed are increased as much as possible. It has been found that if the frame is to be formed by etching, the strength of the dam bar may be reduced and the lead frame may be deformed or the lead frame may be penetrated.

The present invention has been made in view of the above-mentioned problems of the prior art. It is possible to inspect, improve the adhesion of the lead to the resin, extend the life of the blade that cuts into individual semiconductor packages, and prevent the deformation of the lead frame and the penetration of the lead frame due to the decrease in the strength of the dam bar. At the same time, it is an object of the present invention to provide a lead frame capable of increasing the width and height of the portion where the solder connection portion can be visually observed as much as possible.

In order to achieve the above object, a lead frame according to the present invention is a lead frame used in a semiconductor package having a plurality of external connection terminals exposed on a surface and side surfaces connected to an external device, wherein the external connection terminals The terminal portions of the leads having terminal portions for external connection are connected to dam bars, and the individual lead frames are arranged in multiple rows. and a region of the lead excluding the terminal portion serving as the external connection terminal is half-etched. The inside of a second region formed by combining the terminal portion serving as the external connection terminal and the entire region at the position intersecting the terminal portion serving as the external connection terminal in the dam bar. a recess having an opening of a predetermined shape extending over the dam bar and extending to a predetermined position distant from the dam bar relative to a boundary line of a cutting area for cutting into individual semiconductor packages, wherein at least one of the recesses a first rectangular portion having an end at a predetermined position away from the dam bar than a boundary line of the cut region of the terminal portion that straddles the dam bar and becomes the external connection terminal; It is characterized by having a T-shaped or substantially cross-shaped outline formed by a second rectangular portion that straddles the boundary line and vertically intersects the first rectangular portion.

Further, in the lead frame of the present invention, the plate thickness of the region extending over the dam bar of the first rectangular portion in each recess and reaching a predetermined position in the vicinity of the boundary with the second rectangular portion is equal to the thickness of the recess. is preferably thicker than the plate thickness of the second rectangular portion in .

Further, in the lead frame of the present invention, the interval between the sides of the second rectangular portion in each recess, which are parallel to the longitudinal direction of the dam bar, is equal to the distance between the sides of the dam bar of the first rectangular portion. It is preferably shorter than the distance between the sides perpendicular to the longitudinal direction of the .

According to the present invention, the yield and production efficiency of semiconductor package products are improved, and miniaturization can be achieved. This part improves the adhesion of the semiconductor package, prolongs the life of the blade that cuts into individual semiconductor packages, prevents deformation of the lead frame and penetration of the lead frame due to the weakening of the dam bar, and at the same time makes the solder connection part visible. It is possible to obtain a lead frame whose width and height can be increased as much as possible.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory diagram showing the configuration of a main part of a lead frame according to a first embodiment of the present invention, where (a) is a diagram viewed from the side connected to an external device, and (b) is an external connection terminal in the lead frame of (a); (c) is a cross-sectional view along JJ showing a terminal portion serving as an external connection terminal in the lead frame of (a). Explanatory drawing of a recess formed in a terminal portion serving as an external connection terminal of each lead in the lead frame of FIG. A diagram showing an example of the opening shape of the recess, (b) is a KK sectional view of (a), (c) is a diagram showing the first rectangular portion in the opening shape of (a), (d) is (a ) shows a second rectangular portion of the opening shape, (e) shows another example of the opening shape of the recess, and (f) shows still another example of the opening shape of the recess. The length direction and width direction of the recess formed in the terminal portion serving as the external connection terminal in the lead frame of the trial stage before the present inventors derived the present invention and the lead frame of the present invention (a-1) is an explanatory diagram showing the etching depth at each position along the direction of (a-1) formed in the terminal portion that will be the external connection terminal in the lead frame in the trial stage before deriving the present invention A diagram showing the opening shape of the recess, (a-2) is a graph showing the etching depth at each position along the length direction of the recess shown in (a-1), and (a-3) is (a-1). 1 is a graph showing the etching depth at each position along the width direction of the recess shown in FIG. A diagram showing the shape, (b-2) is a graph showing the etching depth at each position along the length direction of the recess shown in (b-1), (b-3) is the recess shown in (b-1) 4 is a graph showing the etching depth at each position along the width direction of the . 1. It is explanatory drawing which shows an example of the manufacturing procedure of the lead frame of FIG. 1 by the JJ 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 II cross section of Fig.1 (a). FIG. 6 is an explanatory diagram showing an example of a manufacturing procedure of a package using the lead frame manufactured by the manufacturing procedure of FIGS. 4 and 5; FIG. 7 is a side view seen from the same side as FIG. 6(e), showing a state in which the external connection terminals of the semiconductor package manufactured by the manufacturing procedure of FIG. 6 are soldered to an external device; FIG. BRIEF DESCRIPTION OF THE DRAWINGS It is explanatory drawing which shows an example of the prior art for making the solder connection part of a semiconductor package visible, (a) is the figure seen from the side which connects with the external device of the lead frame used for a semiconductor package, (b) is (a ) AA cross-sectional view of (a) in the semiconductor package assembled using the lead frame of ), (c) is a diagram showing the state where the external connection terminal of the semiconductor package of (b) is soldered to an external device, ( d) 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 (a). BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory diagram showing an example of the configuration of a main part of a lead frame, which the inventors of the present invention studied in the previous stage of deriving the present invention, (a) is a diagram viewed from the side connected to an external device, (b) is (a ) is a cross-sectional view taken along line C--C showing a terminal portion serving as an external connection terminal in the lead frame of FIG. 1(d), and FIG. FIG. 9 is an explanatory view of a recess formed in a terminal portion that serves as an external connection terminal for each lead in the lead frame of FIG. FIG. 10(b) is a cross-sectional view taken along line EE of FIG. 1(a); FIG. FIG. 10 is an explanatory diagram showing an example of the configuration of a main part of a lead frame, which was studied in the next stage after the lead frame shown in FIG. View from the side connected to the device, (b) is a cross-sectional view FF showing the terminal part for external connection in the lead frame of (a), (d) is for external connection in the lead frame of (a) FIG. 3 is a cross-sectional view taken along line GG showing a terminal portion serving as a terminal; FIG. 11 is an explanatory diagram of a recess formed in a terminal portion that serves as an external connection terminal for each lead in the lead frame of FIG. FIG. 3B is a view showing an example of an opening shape of a recess, and FIG.

Prior to the description of the embodiments, the circumstances leading to the derivation of the present invention and the effects of the present invention will be described.
First, the present inventors studied and considered the technique described in Patent Document 1, which is a conventional technique for making the soldered connection portion of a semiconductor package visible.
The technology described in Patent Document 1 will be described with reference to FIG.

The lead frame shown in FIG. 8(a) has a groove 51b crossing the lead at the cutting position (the position on the dashed line in FIG. 8(a)) of the terminal portion 51 serving as the external connection terminal on the back side of the lead. formed.
Then, the semiconductor element 60 is mounted on the pad portion 52 of the lead frame, the semiconductor element 60 is connected to the terminal portion serving as the internal connection terminal by the bonding wire 61, and the semiconductor package sealed with the resin 70 is placed at the cutting position. 8B, the external connection terminals 51 of the leads exposed on the rear surface of the individually cut semiconductor packages are provided with spaces 51a along the edges.
In the semiconductor package thus formed, as shown in FIG. 8(c), the solder 90 is interposed in the space 51a formed from the back surface of the external connection terminal 51 to the edge. Therefore, it is possible to visually inspect whether the state of solder connection between the semiconductor package and the external device 80 is good or bad.

However, if grooves 51b that cross the leads are formed as in the technique shown in FIG. There is a possibility that the portion 51a may not be formed.
In general, when the semiconductor element mounting side of the lead frame is resin-sealed, a sheet-like tape is attached to the back surface of the lead frame in order to prevent the resin from entering the back surface of the lead frame. However, in the technique shown in FIG. 8, the resin flows from the gap between the sheet-like tape and the surface of the groove 51b during resin sealing, enters the groove 51b of the terminal portion 51, and damages the solder connection portion. A space for visual inspection is not formed, and there is a possibility that the yield of the semiconductor package product is deteriorated.

Next, in the technique described in Patent Document 2, as described above, after resin sealing, two cutting processes, half-cutting and full-cutting, are required using a blade, resulting in poor production efficiency. Since the connecting terminals protrude in the lateral direction, it is disadvantageous in reducing the size of the semiconductor package.

Here, the present inventors mounted a semiconductor element using a lead frame in which a recess was formed at the cutting position of a terminal portion that serves as an external connection terminal, sealed it with resin, and then cut it into individual semiconductor packages. A study was conducted on forming the edges of the external connection terminals exposed on the side surface of the semiconductor package in the manufacturing process to form a gate shape so that the soldered portions can be visually confirmed.

In the course of the above study, the inventors of the present invention have found that this type of lead frame has excellent adhesion to the resin of the lead having a terminal portion serving as an external connection terminal, and a blade for cutting into individual semiconductor packages. It turned out that there was a problem with the lifespan.
Specifically, in this type of lead frame examined by the present inventors, the lead having a terminal portion serving as an external connection terminal is surrounded by resin on both side surfaces and the surface on which the semiconductor element is mounted. However, it has been found that the adhesiveness to the sealing resin that seals the semiconductor element is weak and it is easy to separate. Further, in the lead frame of this type studied by the present inventors, if the thickness of the dam bar for connecting the leads is increased, the amount of metal to be cut into individual semiconductor packages (the volume of the dam bar) increases. There was concern that the number of blades would increase and the life of the blade would be shortened.

Therefore, the inventors of the present invention have developed a method for making the soldered connection part visible, which can solve the above problems, including the problem of the adhesion of the lead to the resin and the life of the blade that cuts into individual semiconductor packages. The technology was further examined.

FIG. 9 is an explanatory diagram showing an example of the essential configuration of the lead frame examined by the present inventors in the preliminary stage of deriving the present invention.

In the lead frame of FIG. 9, on the side of the semiconductor package that is connected to an external device, the entire area at a position that does not intersect with the terminal portion 11-2 serving as the external connection terminal of the dam bar 13, and the external connection terminal of the lead. A first region having a region 11-1 excluding the terminal portion 11-2 is a thin portion that is half-etched. In the example of FIG. 9, the peripheral edge portion of the pad portion 14 and the support lead 15 also form the first region on the side of the semiconductor package that is connected to the external device, and are a thin portion that is half-etched.
In addition, inside the second region formed by combining the terminal portion 11-2 serving as the external connection terminal and the entire region at the position where the terminal portion 11-2 serving as the external connection terminal in the dam bar 13 crosses the terminal portion 11-2 serving as the external connection terminal , straddling the dam bar 13 and at a predetermined position farther from the dam bar 13 than the boundary line of the cutting area for cutting into individual semiconductor packages (indicated by a chain double-dashed line in FIG. 9(a)). A concave portion 11-2b' having a rectangular opening with a constant interval of about 50% of the width of the terminal portion 11-2 serving as an external connection terminal and having a distance between sides perpendicular to the longitudinal direction of the dam bar. formed.
The concave portion 11-2b' is surrounded by a terminal portion 11-2 serving as an external connection terminal and a dam bar 13. As shown in FIG. In FIG. 9A, the cross-sectional shape of the external connection terminal 11-2 exposed on the side surface of the semiconductor package (that is, the edge of the external connection terminal 11-2) is cut at the position of the two-dot chain line. The end surface shape of the portion 11-2a') is formed in a gate shape as shown in FIG. 9(b).

The lead frame shown in FIG. 9 differs from the lead frame shown in FIG. 8 in that the recess 11-2b′ is surrounded by a metal material forming the terminal portion 11-2 or the dam bar 13, which serves as a terminal for external connection. , the surface of the metal material surrounding the recess 11-2b' is flat.
Therefore, the surface of the metal material around the concave portion 11-2b' can be brought into close contact with the sheet-shaped tape, and when the semiconductor element mounting side of the lead frame is sealed with the resin, the concave portion 11-2b' of the resin can be adhered. can be prevented from entering.

In addition, the lead frame shown in FIG. 9 excludes the entire region of the dam bar 13 at a position not crossing the terminal portion 11-2 serving as an external connection terminal and the terminal portion 11-2 serving as an external connection terminal of the lead. Since the first region having the region 11-1 and (furthermore, the peripheral portion of the pad portion 14 and the support lead 15) is a thin portion formed by half-etching, the semiconductor element mounting side of the lead frame is At the time of resin sealing, the resin can enter the space area on the external connection side in the first area. As a result, in the manufacturing stage of the multi-row type semiconductor package, the resin surrounds the first region from the top, bottom, left, and right directions and solidifies. Since the region 11-1 excluding the terminal portion 11-2 is surrounded from the top, bottom, left, and right directions to maintain the solidified state, the adhesion of the lead having the external connection terminal in each semiconductor package product to the resin is remarkably improved. and can prevent detachment from the resin.

In the lead frame shown in FIG. 9, the entire region of the dam bar 13, which does not intersect with the terminal portion 11-2 serving as an external connection terminal, is a half-etched thin portion. A recess 11- Since 2b′ is formed, the amount of metal to be cut (the volume of the dam bar 13) when cutting into individual semiconductor packages can be greatly reduced, and the life of the blade can be greatly extended.

However, as a result of further investigation by the present inventors, as shown in FIG. 10(a), in the lead frame shown in FIG. In a configuration having a rectangular opening with a constant interval of about 50% of the width of the dam bar between the sides perpendicular to the longitudinal direction of the dam bar, as shown in FIG. It is difficult for the etching depth to deepen, and the etching depth becomes shallower toward the edge of the opening, and the etching surface tends to be inclined. , the depth of the concave portion 11-2b' at the position on the boundary line of the cutting area tends to be shallow.
If the depth of the concave portion 11-2b' at the position on the boundary line of the cutting area is shallow, the external connection terminals 11 are exposed on the side surface of the semiconductor package by being cut at the position of the two-dot chain line in FIG. 9(a). The height of the edge portion 11-2a′ in the cross-sectional shape of −2 (that is, the end surface shape of the edge portion 11-2a′ of the external connection terminal 11-2) is lowered, and the soldered connection state is visually recognized accordingly. The area for doing so becomes smaller.

Therefore, the inventors of the present invention next determined that the sides of the recesses 11-2b' in the lead frame shown in FIG. The leadframe shown in FIG. 11 with increased spacing and depth at locations on the boundaries of the cut regions was examined.

The lead frame of FIG. 11 is a second lead frame formed by combining a terminal portion 11-2 serving as an external connection terminal and an entire area at a position intersecting the terminal portion 11-2 serving as an external connection terminal in the dam bar 13. Inside the area of , straddling the dam bar 13 and from the dam bar 13 rather than the boundary line of the cutting area for cutting into individual semiconductor packages (indicated by the two-dot chain line in FIG. 11(a)) 50% or more (about 60% in the example of FIG. 11) of the width of the terminal portion 11-2, which is a terminal for external connection, extending to a predetermined position away from each other, and the width between the sides perpendicular to the longitudinal direction of the dam bar. Recesses 11-2b'' having rectangular openings with intervals are formed. Other configurations are substantially the same as those of the lead frame in FIG.

Like the lead frame in FIG. 11, the recessed part 11-2b'' is more than 50% of the width of the terminal part 11-2 serving as an external connection terminal, and the distance between the sides perpendicular to the longitudinal direction of the dam bar is constant. 11(a), the cross-sectional shape of the external connection terminal 11-2 exposed on the side surface of the semiconductor package by being cut at the position of the two-dot chain line in FIG. 11(a) (that is, the shape of the end surface of the end edge portion 11-2a'' of the external connection terminal 11-2), the horizontal length of the concave end surface forming the inner space region of the end edge portion 11-2a'' is increased. However, the area for visually recognizing the soldered connection state increases accordingly, making it easier to visually inspect the soldered connection portion.

However, when the lead frame shown in FIG. 11 is used, as shown in FIG. becomes too thin. If the thickness of the metal material in the area crossing the dam bar 13 in the concave portion 11-2b'' becomes too thin, the strength of the dam bar 13 is reduced together with other thin portions of the dam bar 13, and accordingly, There is a risk of deformation of a lead or the like having a terminal portion serving as an external connection terminal, which is connected to the dam bar 13 in the lead frame.
Furthermore, as shown in FIG. 12(b), the etching of the region crossing the dam bar 13 in the concave portion 11-2b'' becomes too deep, and There is a risk of penetrating through the second area (combining the entire area at the position intersecting with the terminal portion 11-2 serving as an external connection terminal).

The recesses 11-2b′ and 11-2b″ in the lead frames shown in FIGS. 9 and 11 are intended to form recesses having rectangular openings with narrow intervals between sides perpendicular to the longitudinal direction of the dam bar. In the half-etching process, the etching depth is shallow, and in the half-etching process for forming recesses having rectangular openings with wide intervals between the sides perpendicular to the longitudinal direction of the dam bar, the etching depth is large. Easy to form deep.
In addition, when the concave portion is formed by half-etching, the etching depth is likely to be shallow in the vicinity of the end portion of the concave portion.
For this reason, in order to secure the depth at the position on the boundary line of the cut area located near the end of the concave portion to the extent that the solder connection portion can be easily visually inspected, the vertical direction of the dam bar is required. It is necessary to design the rectangular opening with constant side-to-side spacing so that the side-to-side spacing perpendicular to the longitudinal direction of the dam bar is increased considerably.
In the lead frame shown in FIG. 11, the interval between the sides of the recess 11-2b'' perpendicular to the longitudinal direction of the dam bar is larger than that of the recess 11-2b' of the lead frame shown in FIG. The degree of progress of etching in the half-etching process increases in the central region of the rectangular shape. As a result, there is a greater possibility that the strength of the dambar cannot be maintained, or that the dambar penetrates the second region.
However, customers who manufacture semiconductor packages demand that the horizontal length of the end face of the recess be more than 50% of the width of the terminal portion that serves as the external connection terminal. For this reason, the interval between the sides of the recess on the boundary line of the cutting area, which are perpendicular to the longitudinal direction of the dam bar, cannot be less than 50% of the width of the terminal portion.

In order to solve this problem, the present inventors repeated trial and error, and found that the yield and production efficiency of semiconductor package products could be improved, the size could be reduced, and the solder connection state in the solder connection part could be improved.・Allows visual inspection of defects, improves adhesion of leads with external connection terminals to resin, prolongs the life of blades for cutting individual semiconductor packages, and leads frames due to reduced strength of dam bars. The lead frame of the present invention has been devised which prevents the deformation of the lead frame and penetration of the lead frame, and at the same time, allows the width and height of the portion where the solder connection portion can be visually observed to be increased as much as possible.

The lead frame of the present invention is a lead frame used in a semiconductor package having a plurality of external connection terminals exposed on the side connected to an external device and on the side surface, the lead frame having a terminal portion serving as an external connection terminal. The terminal parts to be the terminals for external connection are connected to the dam bar, and the individual lead frames are arranged in multiple rows, and the terminal parts to be the terminals for external connection of the dam bar intersect on the side of the semiconductor package that is connected to the external device. The first region, which has the entire region at the position where the external connection is not made and the region excluding the terminal portion of the lead that will be the external connection terminal, forms a half-etched thin portion and the terminal that will be the external connection terminal. and the entire region at the position intersecting with the terminal portion serving as the external connection terminal of the dam bar, straddling the dam bar and cutting into individual semiconductor packages inside the second region. A recess having an opening of a predetermined shape extending to a predetermined position away from the dambar beyond the boundary line of the cutting area is formed, and the opening of at least one of the recesses extends across the dambar to the cutting area of the terminal portion that becomes an external connection terminal. A first rectangular portion having an end at a predetermined position further from the dambar than the boundary line, and a second rectangular portion that straddles the boundary line of the cutting area and perpendicularly intersects the first rectangular portion. It has a T-shaped or substantially cross-shaped contour.

Like the lead frame of the present invention, the lead frame of a predetermined shape straddles the dam bar inside the second region and reaches a predetermined position farther from the dam bar than the boundary line of the cutting region for cutting into individual semiconductor packages. By forming a concave portion having an opening, the cross-sectional shape of the terminal portion serving as the external connection terminal becomes gate-shaped, and the solder connection portion when the semiconductor package is solder-connected to an external device is formed in the external connection terminal. It can be visually confirmed from the side of the gate-shaped end face, and it is possible to visually inspect whether the solder connection state of the semiconductor package with an external device is good or bad.

Further, like the lead frame of the present invention, the lead frame has a T-shaped or substantially cross-shaped outline formed by the first rectangular portion formed inside the second region and the second rectangular portion. With this configuration, the degree of progress of etching by the half-etching process increases in the region where the first rectangular portion and the second rectangular portion intersect. However, the second rectangular portion tends to intersect the first rectangular portion in most of its area due to the limitation of the width of the terminal portion serving as the external connection terminal in the longitudinal direction. Therefore, the metal located on the boundary line of the cutting area can be deeply etched by the second rectangular portion perpendicularly intersecting the first rectangular portion.
Moreover, it is not necessary to increase the interval between the sides of the first rectangular portion that do not intersect with the second rectangular portion and that are perpendicular to the longitudinal direction of the dam bar.
Since it is not necessary to increase the distance between the sides of the first rectangular portion that are perpendicular to the longitudinal direction of the dam bar and do not intersect with the second rectangular portion, the depth of etching is reduced in this region. can do. As a result, the strength of the dam bar can be maintained, and penetration of the recessed portion in the region intersecting the dam bar can be prevented.
In addition, by narrowing the distance between the sides of the first rectangular portion in the region intersecting the dambar, which are perpendicular to the longitudinal direction of the dambar, the shape stability of the region is improved. Therefore, by increasing the distance between the sides of the second rectangular portion perpendicular to the longitudinal direction of the dam bar, the dam bar remains on the side of the second rectangular portion in a direction parallel to the longitudinal direction of the dam bar. Even if the thickness of the portion is reduced, the shape of the portion of the lead where the second rectangular portion is formed is stabilized by not increasing the distance between the sides parallel to the longitudinal direction of the dam bar in the second rectangular portion. You can keep your sexuality.
Therefore, if the lead frame of the present invention is used, the width and height of the portion where the solder connection portion can be visually observed are increased as much as possible while preventing deformation of the lead frame and penetration of the lead frame due to a decrease in the strength of the dam bar. It is possible to
For example, in the first rectangular portion, the interval between the sides perpendicular to the longitudinal direction of the dam bar is set to 50% or less (for example, about 40%) of the width of the terminal portion serving as the external connection terminal, and 2, the interval between the sides perpendicular to the longitudinal direction of the dam bar can be set to about 75% of the width of the terminal portion that serves as the external connection terminal.

Further, if the first region is configured to form a half-etched thin portion as in the lead frame of the present invention, when the semiconductor element mounting side of the lead frame is resin-sealed, the resin is applied to the first region. can be inserted into the spatial area on the external connection side of the area of . As a result, in the stage of manufacturing the multi-row type semiconductor package, the resin surrounds the first region from the top, bottom, left, and right directions and solidifies. In order to surround the region 11-1 excluding the terminal portion 11-2 which becomes a terminal from the top, bottom, left, and right directions and keep the solidified state, the adhesion of the lead having the external connection terminal in each semiconductor package product with the resin is remarkably improved, and detachment from the resin can be prevented.

Further, in the lead frame of the present invention, the entire region of the dam bar at a position not intersecting with the terminal portion serving as the external connection terminal forms a half-etched thin portion, and the recessed portion is formed inside the second region. is formed, the amount of metal to be cut (the volume of the dam bar) when cutting into individual semiconductor packages can be greatly reduced, and the life of the blade can be greatly extended.

Further, in the lead frame of the present invention, preferably, the opening of the concave portion formed inside the second region in all the leads having a terminal portion serving as an external connection terminal is the first rectangular portion and the cut portion. It has a T-shaped or substantially cross-shaped outline formed by a second rectangular portion that straddles the boundary line of the region and vertically intersects the first rectangular portion.
In this way, the strength of the dam bar can be maintained for all the leads provided on the lead frame, and the width and height of the portion that allows the solder connection portion to be visually observed while preventing penetration of the recess in the region that intersects the dam bar. The effect of the present invention, which can increase the hardness as much as possible, can be maximized.

Further, in the lead frame of the present invention, preferably, the opening of the recess formed inside the second region is such that the second rectangular portion is located at a predetermined position closer to the dam bar than the end portion of the first rectangular portion. to a predetermined position in the vicinity of the boundary with the dam bar, it has a substantially cross-shaped contour formed by perpendicularly intersecting with the first rectangular portion.
With this configuration, the concave portion formed in the external connection terminal in the semiconductor package has the maximum width and height (depth) in the vicinity of the cut region to allow visual confirmation of the soldered connection state, and the depth of the concave portion from the cut region. It has regions of shallower depth or narrower width intermittently or continuously at distant sites.
As a result, when the recess is soldered, the solder does not uniformly wet and spread in the spatial region inside the recess, but wets and spreads in the vicinity of the cutting region, which is relatively deep and relatively wide in the recess. On the other hand, it becomes difficult to wet and spread in a region having a relatively shallow depth and a relatively narrow width.
As a result, when a semiconductor package manufactured using the lead frame of the present invention is connected to an external device via solder, the solder in the space area inside the recess is unevenly wetted and spreads near the cut area. To increase the amount of protrusion of solder that can be visually inspected on the cut surface of a terminal, to prevent solder bleeding in the area opposite to the cut area, and to prevent short-circuit failure of an external connection terminal. be able to.

In the lead frame of the present invention, the opening of the recess formed inside the second region is such that the second rectangular portion extends from the end of the first rectangular portion to the vicinity of the boundary with the dam bar. It may have a T-shaped contour formed by perpendicularly intersecting the first rectangular portion to a predetermined position.

Further, in the lead frame of the present invention, preferably, the plate thickness of the region extending over the dam bar of the first rectangular portion in each recess and extending to a predetermined position near the boundary with the second rectangular portion is the thickness of the first rectangular portion in the recess. It is thicker than the plate thickness of the rectangular portion of 2.
In this way, the strength of the dam bar can be maintained, and at the same time, the width and height of the portion where the solder connection portion can be visually observed can be increased as much as possible while preventing the penetration of the recess in the area where the dam bar intersects. The effects of the invention can be fully exhibited.

In the lead frame of the present invention, preferably, the distance between the sides of the second rectangular portion in each recess parallel to the longitudinal direction of the dam bar is equal to the distance between the sides of the first rectangular portion in the longitudinal direction of the dam bar. is shorter than the interval between the sides perpendicular to the
In this way, the distance between the sides perpendicular to the longitudinal direction of the dambar in the first rectangular portion that does not intersect the second rectangular portion and intersects with the dambar is narrowed, and the second rectangular portion By increasing the distance between the sides perpendicular to the longitudinal direction of the dam bar, remaining in the direction parallel to the longitudinal direction of the dam bar on the side of the second rectangular portion in the terminal portion that will be the external connection terminal When the thickness of the portion where the second rectangular portion is formed is reduced, the shape stability of the portion of the lead where the second rectangular portion is formed can be maintained.
In addition, the solder connection area in the terminal area that serves as the external connection terminal can be kept as far away from the terminal connection area as possible, and the intrusion of solder due to solder bleeding in the area on the opposite side of the cut area can be suppressed, so that the external connection terminal can be secured. Short-circuit failure can be prevented more reliably.
For example, in the first rectangular portion, the interval between the sides perpendicular to the longitudinal direction of the dam bar is set to 50% or less (for example, about 40%) of the width of the terminal portion serving as the external connection terminal, and The above configuration is effective when the distance between the sides of the rectangular portion 2 perpendicular to the longitudinal direction of the dam bar is set to about 75% of the width of the terminal portion serving as the external connection terminal.

In such a lead frame of the present invention, a first resist mask for etching covering the entire surface is formed on one surface of the metal plate, and terminals serving as external connection terminals are formed on the other surface of the metal plate. and the entire region at the position intersecting with the terminal portion of the dam bar that becomes the terminal for external connection, inside the portion corresponding to the second region that straddles the dam bar and becomes the terminal for external connection. a first rectangular portion having an end portion at a predetermined position further from the dambar than the boundary line of the cutting area for cutting into individual semiconductor packages of the section; and a first rectangular portion straddling the boundary line of the cutting area. forming a first etching resist mask having a T-shaped or substantially cross-shaped opening formed by a second rectangular portion that intersects perpendicularly and covering the other portions; a step of half-etching from the other surface side to form a recess having a T-shaped or substantially cross-shaped opening in a portion of the metal plate exposed from the opening of the first etching resist mask; removing the first etching resist mask; and forming a second etching resist mask that covers the portion constituting the lead frame on one surface of the metal plate and exposes the other portion, A first region having an entire region on the other surface of the metal plate at a position not intersecting with the terminal portion serving as the external connection terminal of the dam bar and a region excluding the terminal portion serving as the external connection terminal of the lead. A step of forming a second etching resist mask having an opening in a portion corresponding to and covering other portions, and etching from both surface sides of the metal plate to form a second etching resist on the metal plate A terminal portion that becomes an external connection terminal when the multi-row lead frame, in which the portion exposed through the opening of the mask is thinned and the individual lead frame regions are connected to the dam bars, is cut into individual semiconductor packages. and a step of removing the second etching resist mask formed on the metal plate.

Therefore, according to the present invention, the yield and production efficiency of semiconductor package products can be improved, miniaturization can be achieved, the solder connection state of the solder connection portion can be visually inspected for good/failure, and moreover, external connections can be made. It improves the adhesion of the lead with the terminal to the resin, prolongs the life of the blade that cuts into individual semiconductor packages, and prevents the deformation of the lead frame and the penetration of the lead frame due to the weakening of the dam bar. A lead frame is obtained in which the width and height of the portion where the connecting portion is visible can be increased as much as possible.

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

First Embodiment FIG. 1 is a diagram of a lead frame according to a first embodiment of the present invention.
For the sake of convenience, the parts different from the configurations shown in FIGS. 9 and 11 will be explained.

The lead frame 1 of the first embodiment, as shown in FIG. It has a recess 11-2b formed inside a second region that combines the entire region at the position.
As shown in FIGS. 2(a) to 2(c), the opening of the concave portion 11-2b is positioned closer to the dam bar 13 than the boundary line of the cut area of the terminal portion 11-2, which straddles the dam bar 13 and becomes an external connection terminal. A first rectangular portion 11-2b1 having an end at a predetermined position away from the first rectangular portion 11-2b1, and a predetermined position near the boundary with the dambar 13 from a predetermined position closer to the dam bar 13 than the end of the first rectangular portion 11-2b1 It has a substantially cross-shaped outline formed by a first rectangular portion 11-2b1 and a second rectangular portion 11-2b2 that vertically intersects across the boundary line of the cutting area.
In addition, as shown in FIG. 2B, the lead frame 1 of the first embodiment has a second rectangular portion 11-1 extending across the dam bar 13 of the first rectangular portion 11-2b1 in each concave portion 11-2b. 2b2 is thicker than the thickness of the second rectangular portion 11-2b2 in the recess 11-2b.
Further, as shown in FIG. 2(a), the length of the side of the second rectangular portion 11-2b2 in each recess 11-2b in the direction perpendicular to the longitudinal direction of the dam bar 13 is the first is shorter than the length of the side of the rectangular portion 11-2b1 in the direction parallel to the longitudinal direction of the dam bar 13. As shown in FIG.
Other configurations are substantially the same as those of FIGS. 9 and 11. FIG.

The opening of the concave portion 11-2b is such that the second rectangular portion 11-2b2 extends from the end of the first rectangular portion 11-2b1 to a predetermined position near the boundary with the dam bar, as shown in FIG. , as shown in FIG. 2(f), it may have a T-shaped contour formed by perpendicularly intersecting the first rectangular portion 11-2b1.
Further, in the lead frame shown in FIG. 1(a), all the openings of the recesses 11-2b are formed by the first rectangular portion 11-2b1 and the second rectangular portion 11-2b2. Although the structure has a cross-shaped contour, at least one opening of the recess 11-2b may have a substantially cross-shaped contour.
Also, the corners of the first rectangular portion 11-2b1 and the second rectangular portion 11-2b2 forming the opening of the recess may be rounded.

Next, an example of the manufacturing process of the lead frame of this embodiment configured as shown in FIG. 1 will be described with reference to FIGS. 4 and 5. FIG.
For convenience of explanation, FIGS. 4 and 5 mainly show the side connected to the external device, and part of the side on which the semiconductor element is mounted is omitted.
First, a copper or copper alloy metal plate 10 is prepared as a lead frame material (see FIGS. 4(a) and 5(a)).
Next, the metal plate 10 is half-etched to form the concave portion 11-2b. Specifically, a first resist layer R1 such as a dry film resist is formed on both surfaces of the metal plate 10 (see FIGS. 4(b) and 5(b)). Next, while exposing the first resist layer R1 on one side of the metal plate 10, a terminal portion to be an external connection terminal and a terminal portion to be an external connection terminal of the dam bar on the other surface of the metal plate 10 Inside the part corresponding to the second area formed by combining the entire area at the position where the A substantially cross formed by a first rectangular portion having an end at a predetermined position away from the dam bar and a second rectangular portion that straddles the boundary line of the cutting area and vertically intersects the first rectangular portion The first resist layer R1 on the other side of the metal plate 10 is exposed and developed using a glass mask on which a pattern corresponding to the shaped opening is drawn, and the inside of the portion corresponding to the second region is exposed. , a first etching resist mask 31 having a substantially cross-shaped opening and covering the other portions is formed (see FIGS. 4(c) and 5(c)). Next, half-etching is performed using an etchant to form a concave portion 11-2b on the other side of the metal plate 10 (see FIGS. 4(d) and 5(d)). At this time, the depth of the recess 11-2b formed by half-etching is such that the bottom surface of the second rectangular portion 11-2b2 shown in FIG. It is deeper than the surface of the area that straddles the dam bar 13 of the rectangular portion 11-2b1 and reaches a predetermined position near the boundary with the second rectangular portion 11-2b2. Next, the first etching resist mask 31 is removed (see FIGS. 4(e) and 5(e)).

Next, the surface of the terminal portion serving as the internal connection terminal of the lead in the lead frame, the surface of the pad portion on which the semiconductor element is mounted, the surface of the terminal portion serving as the external connection terminal, and the inner side of the terminal portion serving as the external connection terminal Plating is applied to the surface of the concave portion 11-2b formed in . Specifically, a second resist layer R2 such as a dry film resist is formed on both surfaces of the metal plate 10 (see FIGS. 4(f) and 5(f)). Next, a second resist layer R2 is formed on both sides of the metal plate 10 using a glass mask on which a pattern corresponding to the terminal portion to be the external connection terminal of the lead, the terminal portion to be the internal connection terminal, and the pad portion is drawn. is exposed and developed, and a plating resist mask 32 is formed by opening portions corresponding to the terminal portions for external connection of the leads, the terminal portions for internal connection, and the portions corresponding to the pad portions, and covering the other portions. is formed (see FIGS. 4(g) and 5(g)). Next, the portions exposed from the plating resist mask 32 are plated with, for example, Ni, Pd, and Au in this order (see FIGS. 4(h) and 5(h)). As a result, a Ni/Pd/Au plating layer (not shown) is formed on the surface of the terminal portion serving as the internal connection terminal of the lead and the surface of the pad portion, and the surface of the terminal serving as the external connection terminal and the concave portion are formed. A Ni/Pd/Au plating layer 12 is formed on the surface.
The surface of the plated layer is preferably roughened. When roughening the surface of the plated layer, for example, the formation of the plated layer may be finished with Ni plating, and the Ni plated layer may be formed with roughening plating. Further, for example, after forming a smooth Ni plating layer, the surface of the Ni plating layer may be roughened by etching. Alternatively, for example, the formation of the plating layer may be finished with Cu plating, and the surface of the Cu plating layer may be roughened by anodizing or etching. Further, for example, after forming the roughening plating layer, Pd/Au plating layers may be sequentially laminated.
Next, the plating resist mask 32 is removed (see FIGS. 4(i) and 5(i)).

Next, by subjecting the metal plate 10 to a half-etching process, the entire region of the dam bar at a position not intersecting with the terminal portion serving as the external connection terminal and the region of the lead excluding the terminal portion serving as the external connection terminal. forming a thinned portion in a first region having . Specifically, a third resist layer R3 such as a dry film resist is formed on both surfaces of the metal plate (see FIGS. 4(j) and 5(j)). Next, the third resist layer R3 on one side of the metal plate 10 is exposed using a glass mask on which a pattern forming a lead frame is drawn, and development is performed. Dambars, leads with terminal parts for external connection, leads with terminal parts for internal connection, pads, and other parts corresponding to the leads that make up the lead frame are covered, and other parts are exposed. A second etching resist mask 33 is formed on the other surface of the metal plate 10, and the entire area of the other surface of the metal plate 10 at a position that does not intersect with the terminal portion for the external connection terminal of the dam bar and the external connection terminal of the lead. The third resist layer R3 on the other side of the metal plate 10 is exposed using a glass mask on which a pattern corresponding to the first region having the region excluding the terminal portion is drawn, and development is performed. Then, on the other side surface of the metal plate 10, a second etching resist mask 33 is formed which has an opening at a portion corresponding to the first region and covers the other portion (FIG. 4(k)). , see FIG. 5(k)). Next, etching is performed from both sides of the metal plate 10 using an etchant to thin the portions of the metal plate 10 exposed through the openings of the second etching resist mask 33, and to form individual lead frame regions. is connected to the dam bar, and the cross-sectional shape of the terminal portion 11, which will be the external connection terminal when cut into individual semiconductor packages, is formed into a gate shape (Fig. 4(l) , see FIG. 5(l)).
Next, the second etching resist mask 33 is removed (see FIGS. 4(m) and 5(m)).
This completes the lead frame 1 of the embodiment of the present invention.

In the plating process (see FIGS. 4(f) to 4(i) and 5(f) to 5(i)), the surface of the terminal portion that will be the external connection terminal and the terminal that will be the external connection terminal It is also possible to omit the surface of the recess formed inside the portion and the surface of the pad portion.
Further, 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 described with reference to FIG. For convenience of explanation, internal connection terminal portions, solder balls, and semiconductor elements on the semiconductor element mounting side, which will be described later, are omitted from the illustration.
First, a semiconductor element is mounted on a pad portion via die bonding, and an electrode of the semiconductor element and a predetermined internal connection terminal portion are wire-bonded (not shown).
Next, a sheet-like masking tape m1 is attached to the side connected to the external device (see FIG. 6A), a mold (not shown) is set, and the semiconductor element mounting side is sealed with resin 21 (see FIG. 6A). 6(b)), at this time, the recess 11-2b is located at a position where the periphery intersects the terminal portion 11-2 serving as an external connection terminal and the terminal portion 11-2 serving as an external connection terminal in the dam bar 13. is surrounded by the outer edge of the second area formed by combining the entire area of The inside of 2b is in a sealed state. Therefore, the resin 21 does not enter the concave portion 11-2b when the sealing resin is formed, and the concave portion 11-2b serves as an external connection terminal for connecting to an external device. Similarly, it is finished in an exposed state.
Next, the masking tape m1 is removed (see FIG. 6(c)), and the semiconductor device 40 is cut into predetermined dimensions (see FIG. 6(d)). As a result, the semiconductor device 40 using the lead frame of this embodiment is completed (see FIG. 6(e)).

According to the lead frame of the first embodiment, the lead frame straddles the dam bar 13 inside the second region and is located at a predetermined position further away from the dam bar 13 than the boundary line of the cutting region for cutting into individual semiconductor packages. Since the concave portion 11-2b having an opening of a predetermined shape is formed, the cross-sectional shape of the terminal portion 11-2 serving as an external connection terminal (for example, the edge portion 11-2a shown in FIG. 1(b) ) becomes a gate shape, and as shown in FIG. It can be visually confirmed from the side of the gate-shaped edge portion 11-2a in 11-2, and it is possible to visually inspect whether the state of solder connection of the semiconductor package to an external device is good or bad.

Further, according to the lead frame of the present embodiment, the substantially cross-shaped lead frame formed by the first rectangular portion 11-2b1 and the second rectangular portion 11-2b2 formed inside the second region. Since it has a contoured configuration, the width and width of the portion where the solder connection portion can be visually observed (for example, the edge portion 11-2a of the terminal portion 11-2 serving as the external connection terminal shown in FIG. 1(b)) It is possible to increase the height as much as possible.
In addition, it is not necessary to increase the distance between the sides of the first rectangular portion 11-2b1 perpendicular to the longitudinal direction of the dam bar 13 that do not intersect with the second rectangular portion 11-2b2. can be made shallower. As a result, the strength of the dam bar 13 can be maintained, and penetration of the recess 11-2b in the region where the dam bar 13 intersects can be prevented.

This point will be supplemented with reference to FIG.
FIG. 3 shows the length direction and width of the recess formed in the terminal portion to be the external connection terminal in the lead frame of the trial stage before the present inventors derived the present invention and the lead frame of the present invention. The etch depth at each location along each of the directions is shown.

As described above, when half-etching is performed to form a concave portion having a rectangular opening with a constant width, the etching depth is shallow in the half-etching process for forming a concave portion having a rectangular opening with a narrow width. In a half-etching process intended to form a concave portion having a wide rectangular opening, the etching depth is likely to be deep.
In addition, when the concave portion is formed by half-etching, the etching depth is likely to be shallow in the vicinity of the end portion of the concave portion.

Then, like the lead frame shown in FIG. 11, the distance between the sides perpendicular to the longitudinal direction of the dam bar 13 in the concave portion 11-2b'' having the rectangular opening shown in FIG. 3(a-1) is is widened so as to obtain an etching depth that facilitates visual inspection of the soldered joint at the position on the boundary line of the cutting area, as shown in Fig. 3(a-2), the position on the boundary line of the cutting area Between P1 and P2, the degree of etching due to the half-etching process is greater in the central region in the longitudinal direction, and exceeds the depth at which visual inspection of the solder joints can be facilitated. As a result, the strength of the dam bar cannot be maintained, and there is an increased risk that (leads of) the lead frame connected to the dam bar will be deformed or penetrate through the second region.

On the other hand, as in the lead frame of the present embodiment, the opening of the recess 11-2b has a substantially cross shape formed by the first rectangular portion 11-2b1 and the second rectangular portion 11-2b2. In the case of the contoured configuration, the degree of progress of etching by the half-etching process increases in the region where the first rectangular portion 11-2b1 and the second rectangular portion 11-2b2 intersect. Therefore, the second rectangular portion 11-2b2 perpendicularly intersecting the first rectangular portion 11-2b1 enables deep etching of the metal located on the boundary line of the cutting area. Then, as shown in FIG. 3(b-2), the depth of etching at positions P1 and P2 on the boundary line of the cut area is visually inspected without fear of deformation or penetration of the lead frame. It can be made as deep as possible to make it easier. Further, the second rectangular portion 11-2b2 widens the interval between the sides perpendicular to the longitudinal direction of the dam bar 13 that etches the metal positioned on the boundary line of the cutting area.
On the other hand, since the first rectangular portion 11-2b1 can deeply etch the metal located on the boundary line of the cutting area by the second rectangular portion 11-2b2, the first rectangular portion 11-2b1 is perpendicular to the longitudinal direction of the dam bar 13. There is no need to widen the spacing between the sides. For this reason, it is not necessary to increase the interval between the sides of the first rectangular portion 11-2b1 perpendicular to the longitudinal direction of the dam bar 13 that do not intersect with the second rectangular portion 11-2b2. -1), the length of the dam bar 13 is narrower than the interval between the sides perpendicular to the longitudinal direction of the dam bar 13 of the recess 11-2b'' in the lead frame shown in FIG. It can be an edge-to-edge spacing that is perpendicular to the direction. If the interval between the sides perpendicular to the longitudinal direction of the dam bar 13 of the first rectangular portion 11-2b1 that does not intersect with the second rectangular portion 11-2b2 is narrowed, the progress of etching is suppressed accordingly. , the etching depth becomes shallower. As a result, as shown in FIG. 3(b-2), the depth of etching between positions P1 and P2 on the boundary line of the cutting area can be visually inspected without fear of deformation or penetration of the lead frame. can be shallower than possible to facilitate
Further, narrowing the distance between the sides of the first rectangular portion 11-2b1 perpendicular to the longitudinal direction of the dam bar 13 in the region intersecting the dam bar 13 improves the shape stability of the region. Therefore, by increasing the distance between the sides of the second rectangular portion 11-2b2 perpendicular to the longitudinal direction of the dam bar 13, the longitudinal direction of the dam bar 13 on the side of the second rectangular portion 11-2b2 is increased. Even if the thickness of the portion remaining in the direction parallel to the lead is reduced, the interval between the sides parallel to the longitudinal direction of the dam bar 13 in the second rectangular portion 11-2b2 is not increased. 2 rectangular portion 11-2b2 is formed, the shape stability can be maintained.
Therefore, according to the lead frame of the present embodiment, the portion where the solder connection portion can be visually observed (for example, the edge portion 11-2a of the terminal portion 11-2 serving as the external connection terminal shown in FIG. 1(b)) while increasing the width and height of the dam bar 13 as much as possible, and at the same time maintaining the strength of the dam bar 13, preventing penetration of the recess 11-2b in the region that does not intersect the second rectangular portion 11-2b2 and intersects the dam bar 13, and can prevent deformation of the lead frame.

Further, according to the lead frame of the present embodiment, since the first region is configured to form a thin portion that is half-etched, when the semiconductor element mounting side of the lead frame is resin-sealed, the resin is applied to the first region. It can be made to enter the spatial region on the external connection side of the region 1. As a result, in the stage of manufacturing the multi-row type semiconductor package, the resin surrounds the first region from the top, bottom, left, and right directions and solidifies. In order to surround the region 11-1 excluding the terminal portion 11-2 which becomes a terminal from the top, bottom, left, and right directions and keep the solidified state, the adhesion of the lead having the external connection terminal in each semiconductor package product with the resin is remarkably improved, and detachment from the resin can be prevented.

Further, according to the lead frame of the present embodiment, the entire region of the dam bar 13 at a position not intersecting with the terminal portion 11-2 serving as an external connection terminal forms a half-etched thin portion, and the second Since the concave portion 11-2b is formed inside the region of the blade, the amount of metal to be cut (the volume of the dam bar) when cutting into individual semiconductor packages can be significantly reduced. It can extend the life significantly.

Further, according to the lead frame of the present embodiment, the opening of the concave portion 11-2b formed inside the second region in all the leads having the terminal portion 11-2 serving as an external connection terminal corresponds to the first and a second rectangular portion 11-2b2 that straddles the boundary line of the cutting area and perpendicularly crosses the first rectangular portion 11-2b1. With this configuration, the strength of the dam bar 13 can be maintained with respect to all the leads provided on the lead frame, and the penetration of the recess 11-2b in the region intersecting the dam bar 13 is prevented, and at the same time, the solder connection portion can be visually observed. The effect of the present invention, which can increase the width and height of the portion (for example, the edge portion 11-2a of the terminal portion 11-2 serving as the external connection terminal shown in FIG. 1(b)) as much as possible, can be maximized. It can be used to a limited extent.

Further, according to the lead frame of the present embodiment, the opening of the concave portion formed inside the second region is such that the second rectangular portion 11-2b2 is located from the end portion of the first rectangular portion 11-2b1. Also, from a predetermined position near the dam bar 13 to a predetermined position near the boundary with the dam bar 13, the first rectangular portion 11-2b1 has a substantially cross-shaped outline formed by perpendicularly intersecting. The recesses formed in the external connection terminals in the semiconductor package have the maximum width and height (depth) that allow visual confirmation of the soldered connection state in the vicinity of the cutting area, and are intermittent in areas away from the cutting area. or continuously have regions of shallower depth or narrower width.
As a result, when the recess is soldered, the solder does not uniformly wet and spread in the spatial region inside the recess, but wets and spreads in the vicinity of the cutting region, which is relatively deep and relatively wide in the recess. On the other hand, it becomes difficult to wet and spread in a region having a relatively shallow depth and a relatively narrow width.
As a result, when a semiconductor package 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 part spreads and wets in the vicinity of the cut area, resulting in external connection. It is possible to increase the amount of solder protruding that can be visually inspected on the cut surface of the terminal for external connection, and moreover, it is difficult for solder bleeding to occur in the area opposite to the cut area, and short-circuit failure of the terminal for external connection is prevented. can do.

Further, according to the lead frame of the present embodiment, the plate in the region extending over the dam bar 13 of the first rectangular portion 11-2b1 in each recess and extending to a predetermined position near the boundary with the second rectangular portion 11-2b2. Since the thickness is thicker than the plate thickness of the second rectangular portion 11-2b2 in the recess, the strength of the dam bar 13 can be maintained and the penetration of the recess 11-2b in the region intersecting the dam bar 13 can be prevented. At the same time, it is possible to increase the width and height of the portion where the soldered connection portion can be visually observed (for example, the edge portion 11-2a of the terminal portion 11-2 serving as the external connection terminal shown in FIG. 1(b)). The possible effects of the present invention can be fully exhibited.

Further, according to the lead frame of the present embodiment, the distance between the sides of the second rectangular portion 11-2b2 in each recess, which are parallel to the longitudinal direction of the dam bar 13, is equal to that of the first rectangular portion 11-2b2. 2b1, the interval between the sides perpendicular to the longitudinal direction of the dambar 13 is shorter than the interval between the sides, so that the first rectangular portion 11-2b2 does not intersect the second rectangular portion 11-2b2 and the first rectangular portion in the area intersecting the dambar 13 The distance between the sides perpendicular to the longitudinal direction of the dambar 13 in the rectangular portion 11-2b1 of the second rectangular portion 11-2b1 is narrowed, and the distance between the sides perpendicular to the longitudinal direction of the dambar in the second rectangular portion 11-b2 is increased. In the case where the thickness of the portion remaining in the direction parallel to the longitudinal direction of the dam bar 13 on the side of the second rectangular portion 11-2b2 of the terminal portion 11-2 serving as an external connection terminal is reduced. , the shape stability of the portion of the lead where the second rectangular portion 11-2b2 is formed can be maintained.
In addition, the solder connection area of the terminal section 11-2, which serves as a terminal for external connection, can be kept as far away from the terminal connection section as possible, thereby suppressing the penetration of solder due to solder bleeding in the area on the opposite side of the cut area, thereby preventing external connection. It is possible to more reliably prevent short-circuit failure of the terminals.

Therefore, according to the present embodiment, the yield and production efficiency of semiconductor package products are improved, and miniaturization can be achieved. It improves the adhesion of leads having connection terminals to resin, extends the life of blades that cut individual semiconductor packages, and prevents lead frame deformation and lead frame penetration due to reduced strength of dam bars. A lead frame is obtained in which the width and height of the portion where the soldered connection portion is visible can be increased as much as possible.

Next, an embodiment of the lead frame of the present invention and a 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 FIGS. 4(a) and 5(a)), and a dry film resist was laminated on both sides as a first resist layer R1. (See FIGS. 4(b) and 5(b)).
Next, using a glass mask on which a predetermined pattern is drawn, both surfaces are exposed and developed to cover one surface and externally connect to the inside of the portion corresponding to the second region on the other surface. A first rectangular portion 11-2b1 having an interval between sides perpendicular to the longitudinal direction of the dam bar, which is 50% of the width of the terminal portion serving as a terminal, and a first rectangular portion 11-2b1 straddling the boundary line of the cutting area and a second rectangular portion 11-2b2 having an interval between sides perpendicular to the longitudinal direction of the dam bar, which is 75% of the width of the terminal portion serving as an external connection terminal and intersects perpendicularly with the second rectangular portion 11-2b2. A first resist mask 31 for etching was formed to cover the rest of the region and to have a substantially cross-shaped opening (see FIGS. 4(c) and 5(c)). In Example 1, the terminal portion serving as the external connection terminal has a width of 0.40 mm and a length of 1.15 mm. 2 is designed to have a width of 0.15 mm and a length of 0.30 mm. Next, using an etchant, the other side of the metal plate 10 was half-etched to a depth of 0.150 mm to form a concave portion 11-2b on the other side of the metal plate 10 (FIG. 4(d)). , see FIG. 5(d)). A ferric chloride solution was used as an etchant. At this time, the depth of the recess 11-2b formed by half-etching is such that the bottom surface of the second rectangular portion 11-2b2 shown in FIG. It is deeper than the surface of the area that straddles the dam bar 13 of the rectangular portion 11-2b1 and reaches a predetermined position near the boundary with the second rectangular portion 11-2b2.
Next, the first etching resist mask 31 was removed (see FIGS. 4(e) and 5(e)).

Next, a dry film resist was laminated as a second resist layer R2 on both surfaces of the metal plate 10 (see FIGS. 4(f) and 5(f)).
Next, a glass mask having a predetermined pattern corresponding to the lead frame shown in FIG. A plating resist mask 32 was formed by opening portions corresponding to the terminal portions and pad portions to be terminals and covering other portions (see FIGS. 4(g) and 5(g)). Next, the portions exposed from the plating resist mask 32 were sequentially plated with Ni at a set thickness of 1.0 μm, Pd at 0.03 μm, and Au at a set thickness of 0.01 μm to form a plating layer 12 (FIG. 4). (h), see FIG. 5(h)).
Next, the plating resist mask 32 was removed (see FIGS. 4(i) and 5(i)).

Next, a dry film resist was laminated as a third resist layer R3 on both surfaces of the metal plate 10 (see FIGS. 4(j) and 5(j)).
Next, using a glass mask on which a predetermined pattern is drawn, both surfaces are exposed to light, developed, and a dam bar, a lead having a terminal portion serving as an external connection terminal, A second etching resist mask 33 is formed to cover portions corresponding to leads having terminal portions to be internal connection terminals, pad portions, and other leads constituting the lead frame, and to expose other portions. A second resist mask 33 for etching was formed on the other side of the metal plate 10, having an opening at a portion corresponding to the first region and covering the other portion (Fig. 4(k), See FIG. 5(k)).
Next, etching is performed from both sides of the metal plate 10 using an etchant to thin the portions of the metal plate 10 exposed through the openings of the second etching resist mask 33, and to separate the individual lead frames. A multi-row lead frame whose regions are connected to dam bars is formed so that the cross-sectional shape of the terminal portion 11, which will be the external connection terminal when cut into individual semiconductor packages, has a gate shape (Fig. 4(l) ), see FIG. 5(l)).
Next, the second etching resist mask 33 was removed (see FIGS. 4(m) and 5(m)). A ferric chloride solution was used as an etchant.
Thus, a lead frame of Example 1 was obtained.

Next, die-bond (not shown), attach a polyimide film with a heat-resistant adhesive as a sheet-shaped masking tape m1 to the side to be connected to an external device (see FIG. 6(a)), and press a mold (not shown). The semiconductor element mounting side was sealed with a resin 21 (see FIG. 6(b)).

At this time, the recess 11-2b is surrounded by the outer edge of the second region, and the outer edge of the second region on the side connected to the external device is in close contact with the sheet-like masking tape m1. Since the inside of 2b is in a hermetically sealed state, resin 21 penetrates into recess 11-2b at the time of forming the sealing resin, similar to terminal portion 11-2, which serves as an external connection terminal on the side connected to an external device. It was finished in a state where it was exposed without any.
Next, the masking tape m1 was removed (see FIG. 6(c)), and the semiconductor package 40 was cut into predetermined dimensions (see FIG. 6(d)). Thus, a semiconductor package 40 using the lead frame 1 of this embodiment was obtained (see FIG. 6(e)).
Next, the external connection terminals 11 of the semiconductor package 40 using the lead frame 1 of this embodiment were soldered to the terminals 81 of the printed circuit board 80, and mounted on the printed circuit board. At this time, the solder 90 wets and spreads in the space formed from the rear surface of the external connection terminal 11-2 to the gate-shaped edge portion 11-2a, and the external connection terminal 11- exposed on the side surface of the semiconductor package 40 spreads. 2 can be visually confirmed, and the condition of the soldered connection between the semiconductor package 40 and the external device 80 can be visually inspected.

Comparative example 1
First, a copper-based material having a thickness of 0.2 mm was prepared as a metal plate, and a dry film resist was laminated on both sides as a first resist layer.
Next, using a glass mask on which a predetermined pattern corresponding to FIG. A first etching resist mask having a rectangular opening having a constant width of 50% of the width of the terminal portion serving as the external connection terminal and covering the other portion was formed inside the portion. In Comparative Example 1, the terminal portion serving as the external connection terminal was designed to have a width of 0.40 mm and a length of 1.15 mm, and the rectangular opening was designed to have a width of 0.24 mm and a length of 0.62 mm. Next, the other side of the metal plate was half-etched to a depth of 0.150 mm using an etchant to form a concave portion 11-2b' on the other side of the metal plate. A ferric chloride solution was used as an etchant. At this time, as shown in FIG. 10(b), the depth of the recess 11-2b' formed by half-etching becomes shallower at the position on the boundary line of the cutting area located near the end. rice field.
Next, the first etching resist mask was removed. Thereafter, a lead frame of Comparative Example 1 was obtained in substantially the same manner as in Example 1.

Comparative example 2
First, a copper-based material having a thickness of 0.2 mm was prepared as a metal plate, and a dry film resist was laminated on both sides as a first resist layer.
Next, using a glass mask on which a predetermined pattern corresponding to FIG. A first etching resist mask having a rectangular opening having a constant width of 60% of the width of the terminal portion serving as an external connection terminal and covering the other portion was formed inside the portion. In Comparative Example 2, the terminal portion serving as an external connection terminal was designed to have a width of 0.40 mm and a length of 1.15 mm, and the rectangular opening was designed to have a width of 0.30 mm and a length of 0.62 mm. Next, the other side of the metal plate was half-etched to a depth of 0.150 mm using an etchant to form a concave portion 11-2b'' on the other side of the metal plate. A ferric chloride solution was used as an etchant. At this time, as shown in FIG. 12(b), the depth of the recess 11-2b'' formed by the half-etching process is the etching depth of the region crossing the dam bar 13 in the recess 11-2b''. became too deep, and the thickness of the metal material at that portion became too thin.
Next, the first etching resist mask was removed. Thereafter, a lead frame of Comparative Example 2 was obtained in substantially the same manner as in Example 1.

Measurement of the depth of the recess Each of the lead frames of Example 1 and Comparative Examples 1 and 2 was half-etched at a design value of 0.15 mm to form external connection terminals for a plurality of leads provided on each lead frame. The depths of the recesses 11-2b, 11-2b′, and 11-2b″ formed in the terminal portion 11 are determined from the position on the boundary line of the cutting area and the area extending to the vicinity of the boundary line of the cutting area across the dam bar. Measured at
Table 1 shows the measurement results.

As shown in Table 1, in the lead frame of Example 1, the depth of the recess 11-2b is 0.15 mm on the boundary line of the cutting area in the second rectangular portion 11-2b2, and the depth of the first rectangular portion 11-2b2 is 0.15 mm. The area extending over the dam bar 13 in 2b1 and extending to a predetermined position near the boundary with the second rectangular portion 11-2b2 is 0.12 mm to 0.14 mm, and the portion where the solder connection portion in the lead frame can be visually observed (for example, It was found that the width and height of the edge portion 11-2a) of the terminal portion 11-2 serving as the external connection terminal shown in FIG. As a result, it was confirmed that there was no fear of penetration of the lead frame.

On the other hand, in the lead frame of Comparative Example 1, the depth of the recess 11-2b′ is 0.12 mm on the boundary line of the cutting area, and in the area extending over the dam bar 13 to a predetermined position near the boundary line of the cutting area. It is 0.12 mm to 0.14 mm, and although it was confirmed that there is no risk of deformation of the lead frame or penetration of the lead frame due to a decrease in the strength of the dam bar, the part where the solder connection part of the lead frame is visible (for example, FIG. As a result, it was found that the width and height of the edge portion 11-2a') of the terminal portion 11-2 serving as the external connection terminal shown in 9(b) could not be increased.

In addition, in the lead frame of Comparative Example 2, the depth of the recess 11-2b'' remains at 0.15 mm on the boundary line of the cutting area, while straddling the dam bar 13 and reaching a predetermined position near the boundary line of the cutting area. 0.15 mm in the region, and 0.18 mm at the center position in the width direction of the dam bar 13, and the portion (for example, the external connection terminal shown in FIG. It is recognized that it is difficult to increase the height of the edge portion 11-2a'') of the terminal portion 11-2, and there is a concern that the lead frame may deform or penetrate through the lead frame due to a decrease in the strength of the dam bar. result.

Deformation and Penetration Inspection of Lead Frame For each of the lead frames of Example 1 and Comparative Examples 1 and 2, 1000 multi-row lead frame sheets were prepared with 10 vertical and 40 horizontal lead frames. The presence or absence of deformation and penetration of the lead frame formed on the sheet was inspected.
The presence or absence of deformation of the lead frame was determined using a 20-fold stereoscopic microscope.
Further, the presence or absence of penetration of the lead frame was determined using a 200-fold metallographic microscope.
Table 2 shows the test results.

As shown in Table 2, none of the lead frames of Example 1 and Comparative Example 1 were found to be deformed or penetrated.
On the other hand, in the lead frame of Comparative Example 2, deformation was recognized in 225 lead frames, and penetration was recognized in 161 lead frames, resulting in a significant drop in product yield. .

Although the preferred embodiments and examples of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments and examples, and can be modified without departing from the scope of the present invention. Various modifications and substitutions can be made to the examples.

For example, in the above-described embodiments and examples, a lead frame of a type provided with pad portions and support leads for supporting the pad portions was shown. The configuration of the present invention can also be applied to a lead frame of a type that has leads having terminal portions of different shapes and that is flip-chip connected to the semiconductor element on the semiconductor element mounting side of the lead.

1 lead frame 10 metal plate 11 lead having a terminal portion that serves as an external connection terminal 11-1 area of the lead excluding the terminal portion 11-2 that serves as an external connection terminal 11-2, 51 terminal that serves as an external connection terminal (or external connection terminal)
11-2a, 11-2a', 11-2a'' Gate-shaped edge 11-2b, 11-2b', 11-2b'' Recess 11-2b1 First rectangular portion 11-2b2 Second rectangle Part 12 Plated layer 13 Dam bar 14 Pad part 15 Support lead 21 Sealing resin 31 First resist mask for etching 32 Resist mask for plating 33 Second resist mask for etching 40 Semiconductor package 51a Space part 51b Groove 52 Pad part 53 Dam bar 60 semiconductor element 61 bonding wire 70 sealing resin 80 external device 81 terminal 90 solder m1 masking tape R1 first resist layer R2 second resist layer R3 third resist layer

Claims (3)

A lead frame used in a semiconductor package having a plurality of external connection terminals exposed on a surface connected to an external device and a side surface,
The terminal portion of the lead having the terminal portion serving as the external connection terminal is connected to a dam bar, and the individual lead frames are arranged in multiple rows,
On the side of the semiconductor package that is connected to an external device,
A first region having an entire region of the dam bar at a position not intersecting with the terminal portion serving as the external connection terminal and a region of the lead excluding the terminal portion serving as the external connection terminal is half-etched. While forming a processed thin-walled part,
Straddling the dam bar inside a second region formed by combining the terminal portion serving as the external connection terminal and the entire region at the position intersecting the terminal portion serving as the external connection terminal in the dam bar, and forming a recess having an opening of a predetermined shape extending to a predetermined position away from the dam bar from a boundary line of a cutting area for cutting into individual semiconductor packages,
at least one opening of the recess,
a first rectangular portion having an end at a predetermined position apart from the dam bar than the boundary line of the cut area of the terminal portion that straddles the dam bar and becomes the external connection terminal;
a second rectangular portion that straddles the boundary line of the cutting area and perpendicularly intersects the first rectangular portion;
A lead frame characterized by having a T-shaped or substantially cross-shaped contour formed by: The plate thickness of the region extending over the dam bar of the first rectangular portion in each of the recesses to a predetermined position near the boundary with the second rectangular portion is the plate thickness of the second rectangular portion of the recess. 2. The leadframe of claim 1, wherein the leadframe is thicker than the . In each of the recesses, the distance between the sides of the second rectangular portion parallel to the longitudinal direction of the dam bar is equal to the distance between the sides of the first rectangular portion perpendicular to the longitudinal direction of the dam bar. 2. Lead frame according to claim 1, characterized in that the spacing is shorter than the spacing of .

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