JP2866816B2 - Lead frame - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device, and more particularly to a lead frame suitable for manufacturing a resin-sealed semiconductor device and a method for manufacturing a semiconductor device using the same.

[0002]

2. Description of the Related Art A conventional method for manufacturing a lead frame for a semiconductor device and a resin-sealed IC package using the same is shown in FIG.
This will be described with reference to FIG. First, as shown in FIG.
After mounting the semiconductor chip 2 on the lead frame 1 and performing processing such as bonding, the semiconductor chip 2 is sealed with a resin such as an epoxy resin. The lead frame 1 is provided with a tie bar 5 extending in a direction orthogonal to the outer leads 4, 4,..., And when the resin is sealed, the resin flows in a direction parallel to the outer lead 4 by the tie bar 5. Can be blocked. A gap between the edge of the resin sealing portion 3 and the tie bar 5 is referred to as a resin dam portion 6.

Next, as shown in FIG. 10, the resin of the tie bar 5 and the resin dam portion 6 is cut by a mold or the like. FIG. 11 is an enlarged view of the tie bar 5 and the resin dam portion 6, but large burrs 7 of resin are formed along the outer leads 4 in the resin dam portion 6. Therefore, high-pressure water or high-pressure water mixed with glass powder or the like is sprayed on the resin burr 7 remaining after the tie bar cutting step, and the resin burr 7 is removed.

Then, after plating the lead frame 1, the outer leads 4 are cut and formed using a mold or the like as shown in FIG. Next, when the lead frame outer frame 8 is cut off, the resin-sealed mold I as shown in FIG.
The C package 9 is completed.

[0005]

However, in the method of manufacturing the resin-sealed IC package 9 described above, FIG.
In the cutting process of the tie bar 5 and the resin dam 6 shown in FIG. 11, the resin of the tie bar 5 and the resin dam 6 is usually cut by a cutting blade such as a mold. (SiO 2) as a filler for adjusting the thermal expansion coefficient, etc.
_{Since 2} ) was included, the cutting blades were severely worn, and many management costs were required for checking and replacing the degree of wear of the cutting blades.

In the above method, a resin burr removing step is provided after the tie bar cutting step, for the following reason. That is, if molding of the outer lead 4 is performed while the resin burr 7 remains, the conventional lead frame 1 moves the outer lead 4 at a position closer to the resin sealing portion 3 than the position where the tie bar 5 is provided on the outer lead 4. Since the lead 4 is designed to be bent (indicated by a broken line A in FIG. 11), the resin burr 7 is also bent together with the outer lead 4. Then, at this time, the resin burr 7 peels off from the lead frame 1 and adheres to the outer lead 4 or the like, so that a mounting failure occurs. Therefore, a resin burr removal step is essential in the manufacturing process. However, just as with the step using high-pressure water, similar to the above-described tie-bar cutting step, the management cost increases, and the manufacturing process becomes complicated. Had occurred.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and a lead frame capable of reducing the management cost and simplifying the process in the process of manufacturing a resin-encapsulated semiconductor device. It is an object of the present invention to provide a method for manufacturing a semiconductor device using a semiconductor device.

[0008]

According to a first aspect of the present invention , there is provided a lead frame for connecting a plurality of outer leads and extending in a direction orthogonal to the outer leads. In a lead frame provided with a tie bar used for preventing resin from flowing when performing resin sealing of a semiconductor chip mounted thereon, at least a part of a cross section between each outer lead of the tie bar crossing the outer lead is provided. There the cutting unit is provided that is sandwiched between a pair of cut surfaces obtained by cutting, the cut
The width of the cut portion is the width of the outer lead tip side
It is characterized in that it has a wider planar shape than that of .

[0009]

[0010]

[0011]

[0012]

In the lead frame according to the first aspect,
The tie bar is not completely integral with the plurality of outer leads, but is a cut portion sandwiched between a pair of cut surfaces at least partially cut at a crossing portion between the outer leads, that is, the outer portion only at a part. It has a configuration having a cutting portion connected to the lead. Therefore, as a step corresponding to the tie bar cutting step in the conventional method of manufacturing a semiconductor device, a step of removing the cut portion by pushing it down from between the outer leads may be provided. There is no need to use it. Further, when removing the cut portion, resin burrs attached to the cut portion are also removed at the same time. In addition, the width of the cut part is wide on the resin sealing part side,
ー Because it is narrow at the lead tip side,
The tie bar is only partially connected to the outer lead side
Even if the cutting part is outer due to the pressure of the resin at the time of resin sealing
The tie bar does not move by being pushed by the lead tip side.
Does not function as a resin flow stopper.

When the position of the tie bar is set within the range from the edge of the resin sealing portion to the portion bent at the time of forming the outer lead, the dimension from the resin sealing portion to the tie bar (resin dam portion) Is smaller than that of a conventional lead frame. Therefore, the amount of resin burr generated in this portion itself is smaller than before, and
Even if resin burrs remain after the cut portion is removed, the resin burrs are not bent at the same time as the outer lead is bent in the next step.

[0014]

In a method of manufacturing a semiconductor device using a lead frame according to the present invention , a semiconductor chip is mounted and bonded in a first step, and a semiconductor chip is sealed with a resin. After plating the lead frame, in the third step, each outer lead is separated by pushing down the cut portion without cutting the tie bar with a cutting blade such as a mold, and thereafter, cutting each outer lead, The semiconductor device is completed by molding.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a view showing a lead frame 11 of the present embodiment.
This is a lead frame for a resin-sealed semiconductor device made of Ni or the like. In the drawing, reference numeral 12 denotes a lead frame outer frame, 13 denotes a suspension lead, 14 denotes a chip mounting portion, 15 denotes an inner lead, 16 denotes an outer lead, 17 denotes a tie bar, and 19 denotes a cutting portion. FIG. 2 is an enlarged view of a tie bar 17 portion, and FIGS.
It is a figure showing the manufacturing process of.

The lead frame 11 is formed so that a plurality of semiconductor devices can be continuously mounted by repeatedly forming the same pattern in one lead frame outer frame 12, but FIG. Only one of the patterns is shown.

As shown in FIG. 1, a chip mounting portion 14 for fixing a semiconductor chip and a lead frame outer frame 12 are connected by suspension leads 13. Further, a plurality of inner leads 15, 15,... (In this case, five on each side) for electrically connecting to the semiconductor chip by means such as wire bonding are formed around the chip mounting portion 14. When the semiconductor device is completed, the inner lead 15 embedded in the resin extends outward from the resin sealing portion 18, and is connected to the lead frame outer frame 12 as an outer lead 16.

A tie bar 17 extending in a direction perpendicular to the outer leads 16 and connecting the outer leads 16 is formed near the resin sealing portion 18 of the outer leads 16. The tie bar 17 serves to prevent the resin from flowing when the mounted semiconductor chip is sealed with resin. Further, as shown in FIG. 2, the tie bar 17 is separated from the edge of the resin sealing portion 18 on the outer lead 16 by a certain size or more (for example, 0.03 mm or more as an example of a size), and is bent when the outer lead 16 is formed. It is formed in a range closer to the resin sealing portion 18 than a location (indicated by a broken line B in FIG. 2).

The tie bar 17 has a pair of cut surfaces 3 partially cut at the portions between the outer leads 16.
The cutting portion 19 sandwiched between 3, 33 is press-fitted. That is, in the present embodiment, the cutting portion 19 is not completely cut with the other portions, but is connected to the outer lead 16 side in a part of the plate thickness direction as described later. The planar shape is as shown in FIG.
Its width is widened on the resin sealing portion 18 side and narrow on the distal end side of the outer lead 16 in a reverse tapered shape.

Here, in the manufacturing process of the lead frame 11 having the above-mentioned structure, a procedure for forming the cut portion 19 will be described below with reference to FIGS. 3 (a) and 3 (b). FIG.
(A) is a figure which shows the state of the bottom dead center of a metal mold | die at the time of tie-bar cutting in the cutting | molding shaping | molding die used in a lead frame manufacturing process.

As shown in FIG. 3A, a tie bar 1 is formed by a lower mold receiver 20, an upper mold cutting blade 21 and a stripper 22.
When the mold is lowered with holding the lower die 7, the lower die cutting edge 23 bites into the tie bar 17 and the lower die cutting edge 23
The tie bar 17 is cut by the and the upper cutting edge 21. However, at this time, in order to prevent the cutting portion 19 from being completely separated from the tie bar 17, the thickness of the tie bar 17 is 1/3 to 1/3.
A cutting mold is set in advance so that the lower cutting edge 23 does not bite into only about two ranges. When the mold is lifted, the cutting portion 19 is pushed downward by the spring force of the stripper 22 so that the upper die cutting blade 21 does not pull upward with the cutting portion 19 interposed therebetween.

FIG. 3 (b) is a view showing the state of the bottom dead center of the die when the cutting part is press-fitted in the die. After the tie bar cutting step is completed, when the tie bar 17 is pressed by the upper mold 24 and the lower mold 25 from above and below, the cutting portion 19 is formed.
Is press-fitted. Through such a procedure, the formation of the cut portion 19 of the tie bar 17 in the lead frame 11 of the present embodiment is completed.

Hereinafter, a method of manufacturing a semiconductor device using the lead frame 11 of this embodiment will be described with reference to FIGS. FIG. 4 is a view showing a state after a resin sealing step in a manufacturing process of the semiconductor device, FIG. 5 is an enlarged view of a tie bar portion in this state, and FIG. 6 is an enlarged view showing a tie bar and a mold when a cut portion is removed. FIG. 7 is a view showing a state after a cut portion removing step and an outer lead forming step, and FIG. 8 is a completed view of the semiconductor device.

First, as shown in FIG. 4, the semiconductor chip 26 is mounted on the lead frame 11, and the semiconductor chip 26 and the inner leads 1 are processed by wire bonding or the like.
After the electrical connection of No. 5, the semiconductor chip 26 and the inner leads 15 are sealed with a resin such as an epoxy resin (first step). In this state, as shown in FIG. 5, the dimension between the edge of the resin sealing portion 18 and the tie bar 17 is extremely small (0.03 mm in this example).
The area of the resin dam portion 27 between the edge of the tie bar 17 and the tie bar 17 is very small.

Thereafter, portions of the lead frame 11 other than the resin sealing portion 18 are plated with tin or the like (second plating).
Process). Next, the cutting portion 19 is removed from the tie bar 17 using a pin of a cutting mold. That is, as shown in FIG. 6, the tie bar 17 is held by the lower mold 28 and the upper mold 29, and the cut portion 19 is pushed down by the push-down pin 30. The lower mold 28 and the push-down pin 3
The dimension 0 is provided with a clearance with respect to the width of the cut portion 19 so as not to cause wear between the tie bar 17 and the cut portion 19.

At the same time as the removal of the cut portion 19,
As shown in FIG. 7, the connection between the lead frame outer frame 12 and the outer lead 16 is cut off, and the outer lead 16 is cut.
(Third step). At the stage after the connection between the lead frame outer frame 12 and the outer lead 16 is cut, the semiconductor device 31 is held on the lead frame outer frame 12 by the suspension leads 13. Then, the suspension lead 13
When the lead frame outer frame 12 is removed by cutting the
Is completed.

The lead frame 11 of the present embodiment is different from the conventional lead frame in that the tie bars are not completely integrated with the outer leads.
The cutting portion 19 is press-fitted therebetween. Therefore, in the method of manufacturing the semiconductor device using the lead frame 11, a step of removing the cut portion 19 from between the outer leads 16 after resin sealing is provided as a step corresponding to the tie bar cutting step in the conventional manufacturing method. It is no longer necessary to use a cutting edge of a mold as in the related art. Further, in the cutting portion removing step in the manufacturing method of the present embodiment, the cutting mold has a structure in which the lower mold 28 and the push-down pin 30 do not wear. Therefore, it is possible to suppress an increase in management cost due to abrasion of the cutting edge of the mold, which is a problem in the conventional manufacturing method.

Further, when the cutting portion 19 is pushed down, resin burrs attached to the cutting portion 19 are also removed at the same time.
The step of removing resin burrs by high-pressure water, which is required in the conventional manufacturing method, can be omitted, and a rise in management cost due to the step of removing resin burrs can be suppressed. In addition, since the tie bar cutting step and the resin burr removing step can be omitted, the manufacturing process can be simplified.

The tie bar 17 is connected to the outer lead 1.
(6) Since it is formed closer to the resin sealing portion 18 than to be bent at the time of molding, the dimension from the resin sealing portion 18 to the tie bar 17 (the size of the resin dam portion 27) is smaller than that of a conventional lead frame. Has become. Therefore,
When the amount of resin burrs generated in this portion becomes smaller than before and small resin burrs remain after the cut portion is removed, the resin burrs may be bent together with the outer leads 16 at the time of forming the outer leads 16 in the next step. Absent. Therefore, the resin burrs do not peel off from the lead frame 11, and the mounting failure caused by this can be reliably prevented.

In the formation of the cut portion 19, the cut portion 19 is not completely cut off from the lead frame 11, but is only cut into a part in the plate thickness direction. Because of the connection, the cutting portion 19 is securely held between the outer leads 16, and the cutting portion 19 can be formed only by making a cut at the time of manufacturing the lead frame, so that the press-fitting of the cutting portion 19 by a mold or the like is easy. Become. Therefore, the configuration of the lead frame 11 of this embodiment can be realized without complicating the manufacturing process of the lead frame so much.

Further, as for the planar shape of the cut portion 19, the width thereof is wide on the resin sealing portion 18 side and the outer lead 16
Tie bar 1
Even if 7 is connected to the outer lead 16 side only in a part of the thickness direction in the cutting portion 19, the cutting portion 19 may be pushed to the outer lead 16 tip side and moved by the pressure of the resin at the time of resin sealing. In addition, as in the case of the conventional lead frame, the function of preventing the resin from flowing can be reliably achieved.

That is, the lead frame 11 of the present embodiment
According to the method of manufacturing a semiconductor device using the semiconductor chip 26, processing such as mounting and bonding of the semiconductor chip 26,
After the resin sealing is performed and the lead frame 11 is plated, the outer leads 16 are separated by pushing down the cut portions 19 without cutting the tie bars 17 with a cutting blade such as a mold. By cutting and molding the outer leads 16, a semiconductor device 31 having no mounting failure is completed. Accordingly, the elimination of the tie bar cutting step using the cutting blade and the resin burr removing step using high-pressure water can simplify the manufacturing process and shorten the delivery time.

In this embodiment, the cutting section 19
Has a configuration in which a cut is made in a part of the plate thickness direction and the remaining part is connected to the outer lead 16 side.
The configuration of the cutting portion is not limited to this. For example, a configuration may be adopted in which a cut is made partially from the front end side of the outer lead and connected to the resin sealing portion side, or once cut off completely from the outer lead side. After the pieces are cut, the cut pieces may be press-fitted to the original position again. Then, by cutting at least a part of a pair of cut surfaces sandwiching the cut portion, the cut portion can be easily pushed down in a later cut portion removing step, and can function as a resin stop. Then, the specific shape of the cutting portion may be any.

In this embodiment, the lead frame 11 having the structure shown in FIG. 1 has been described. However, the present invention is applied to various types other than those shown in FIG. Of course you can. Various materials can be used for the lead frame material and the resin material. Well-known methods may be appropriately used for each step of the semiconductor manufacturing process, for example, a mounting step of a semiconductor chip on a lead frame, a bonding step, a plating step, a resin sealing step, and the like.

[0036]

As described in detail above, claim 1 is as follows.
Has a configuration in which a tie bar has a cut portion sandwiched between a pair of cut surfaces at least partially cut between each outer lead. Therefore, it is sufficient to provide a process of removing and cutting the cut portion from between the outer leads as a process corresponding to the tie bar cutting process in the conventional manufacturing method, and it is necessary to use a cutting blade such as a mold as in the conventional case. Disappears. Therefore, it is possible to suppress an increase in management cost due to abrasion of the cutting edge of the mold, which is a problem in the conventional manufacturing method. Furthermore, since the resin burrs attached to the cut portion are also removed when the cut portion is pushed down, the resin burr removal step using high-pressure water in the conventional manufacturing method can be eliminated, and the management cost due to the resin burr removal step can be reduced. At the same time as the rise can be suppressed, the manufacturing process of the semiconductor device can be simplified. In addition, the width of the cut section is wide on the resin sealing
Because the tie bar is narrower at the tip of the outer lead,
Only partially connected to the outer lead side at the cutting section
Even when the resin is sealed, the cut part is
Without being pushed to the tip of the
As with the frame, the function as a resin stop is ensured.
Can be fulfilled.

Further , when the position of the tie bar is set within the range from the edge of the resin sealing portion to the portion where the outer lead is bent at the time of forming the outer lead, the amount of resin burr itself becomes smaller than in the conventional case . Further, when the resin burrs remain, the resin burrs are not bent together with the outer leads at the time of forming the outer leads in the next step. Therefore, the resin burrs do not peel off from the lead frame, and the mounting failure caused by this can be reliably prevented.

[0038]

In the method of manufacturing a semiconductor device using a lead frame according to the present invention, processing such as mounting and bonding of a semiconductor chip and resin sealing of the semiconductor chip are performed in a first step. After plating the lead frame, in the third step, each outer lead is cut off by cutting down the cut portion without cutting the tie bar with a cutting blade such as a mold. By cutting and molding the outer leads, a semiconductor device free from defective mounting is completed. Accordingly, the elimination of the tie bar cutting step using the cutting blade and the resin burr removing step using high-pressure water can simplify the manufacturing process and shorten the delivery time.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a lead frame according to an embodiment of the present invention.

FIG. 2 is an enlarged plan view of a tie bar portion of the lead frame.

FIG. 3 (a) in the same lead frame manufacturing process.
It is a sectional side view at the time of cutting a tie bar part, and (b) a sectional side view at the time of press-fitting of a cutting part.

FIG. 4 is a perspective view showing a state after a resin sealing step in the method of manufacturing a semiconductor device using a lead frame.

FIG. 5 is an enlarged plan view of a tie bar portion after a resin sealing step.

FIG. 6 is a side sectional view showing a state when a cut portion is removed in the manufacturing method.

FIG. 7 is a perspective view showing a state after a cut portion removal step and an outer lead cutting and forming step in the manufacturing method.

FIG. 8 is a perspective view showing a state after a lead frame outer frame removing step in the manufacturing method.

FIG. 9 is a perspective view showing a state after a resin sealing step in a conventional method for manufacturing a semiconductor device.

FIG. 10 is a perspective view showing a state after a tie bar and a resin burr cutting step in the manufacturing method.

FIG. 11 is an enlarged plan view of a tie bar and a tie bar portion after a resin burr cutting step.

FIG. 12 is a perspective view showing a state after a cutting and forming step of an outer lead in the manufacturing method.

FIG. 13 is a perspective view showing a state after a lead frame outer frame removing step in the manufacturing method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Lead frame 12 Lead frame outer frame 13 Suspension lead 14 Chip mounting part 15 Inner lead 16 Outer lead 17 Tie bar 18 Resin sealing part 19 Cutting part 26 Semiconductor chip 27 Resin dam part 31 Semiconductor device

Claims (1)

(57) [Claims] A plurality of outer leads and a tie bar which extends in a direction perpendicular to the outer leads, connects the outer leads, and is used to prevent resin from flowing when performing resin sealing of a mounted semiconductor chip. the lead frame provided, the the transverse portion between the outer leads of the tie bar across the outer lead, the cutting portion at least partially interposed between a pair of the cut surface which is cut is provided, the cutting portion
However, the width on the resin sealing portion side is the width on the tip side of the outer lead.
A lead frame characterized in that it has a wider planar shape than that of .