JP2704128B2 - Lead frame for semiconductor device and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lead frame for a semiconductor device, and more particularly to a lead frame for a semiconductor device having an improved method of removing a resin pool when a molding resin is filled.

[0002]

2. Description of the Related Art In recent years, the degree of integration of semiconductor devices has been improved with the development of microfabrication technology, and the application fields have been used in a wide range of equipment including industrial equipment and consumer equipment. Was. For this reason, a semiconductor device having a package with a shape that is easy to use for each device such as miniaturization, thinning, and increase in the number of pins has been commercialized.

[0003] Among the package forms used in these semiconductor devices, DIP (dual in
-Line package) type, QFP (quad)
flat package) and QUIP (qu
ad in-line) type.

When constructing these packages,
A lead frame using a conductive metal material is used. The lead frame includes a method of punching a thin metal plate by press working to obtain a desired shape and a method of etching. A semiconductor chip is mounted on the island of the lead frame, and its electrodes and inner leads arranged around the island are electrically connected by wire bonding using a thin metal wire (wire).
These are sealed with a resin.

At the time of the above-described resin sealing, a lead frame on which a semiconductor device is mounted is housed in a cavity formed in accordance with the shape of a predetermined package, and one side of a suspension pin of an island on which the semiconductor device is mounted. Is filled with resin. In that case, one of the methods developed for uniformly encapsulating the resin on both the upper and lower surfaces of the lead frame is to form a hole called a resin flow hole in an area including the suspension pin and the corner, and The resin injected from the lower surface side also flows into the upper surface through the resin flow holes, and the resin is injected uniformly on both upper and lower surfaces.

FIG. 5A shows a plan view of an example of a lead frame, FIG. 5B shows a plan view of a lead frame after resin encapsulation, and a step of sealing the lead frame with resin. 6 (a) showing a cross-sectional view of a lead frame before encapsulation, FIG. 6 (b) showing a cross-sectional view of a resin encapsulation start state, and FIG. 6 showing a state after encapsulation of resin.
(C) FIG. 6 is a cross-sectional view showing a state where the package after encapsulation is separated into individual packages by gate break.
Referring to (d) together, the lead frame 1 using a conductive material is located between the island 2, the inner lead 3, the outer lead 4, and between the inner lead 3 and the outer lead 4, and supports these lead groups. The width of one of the tie bar 5, the gate portion 6 in the corner portion area where the outer lead 4 is not arranged in the four corner portions, and the hanging pin 7 connected to the corner portion is partially expanded. , Its expanded part and gate part 6
And a resin flow hole 8 opened in a region including
A semiconductor chip 21 is mounted on the island 2, and its input / output electrodes and the inner leads 3 are connected by wires 22.

In general, resin encapsulation is performed simultaneously for a plurality of lead frames 1 on which a semiconductor chip 21 is mounted. That is, when a plurality of lead frames
Mold lower mold 23 heated to a high temperature of ° to 180 ° C
And set by being sandwiched between upper molds 24, and clamped by a mold press.
The package is transfer molded by injecting into a mold at a low pressure of 0 Kg / cm ² .

[0008] At this time, the mold sandwiching both packages <br/> Cavity I is connected by the resin inlet path, the intermediate portion cull part 26 by a resin feeding section 27 resin provided on (FIGS. 6A and 6B).

Due to the injection pressure of the thermoplastic resin, the resin flows under the lead frame 1 in the resin inflow passage and flows between the inner leads 3 or between the inner leads 3 and the die pad 2. Cavite on top of
It is also filled in the space . Since this time the resin flow from resin flow hole 8 described above flows into the upper surface of the lead frame 1, is in the cavitation I would resin is uniformly filled.

The package in which the lead frame 1 is enclosed is in a state where a plurality of packages are connected by a resin, and the resin of the cull portion 26 formed in the middle portion thereof is fixed by sandwiching the resin from above and below with a molding punch 28, and is fixed to the package. The package is separated into individual packages (gate break) by applying downward pressure (FIG. 5C).

Outside the resin-sealed package, the outer leads 4, the tie bars 5, the gate portions 6, and the resin flow holes 8 where the inner leads 3 are extended are exposed. A resin reservoir 29 is formed on the upper and lower surfaces of the hole so as to protrude from the peripheral edge thereof (FIGS. 5B and 6D).

The above-mentioned resin reservoir 29 is an unnecessary part for a package, and therefore needs to be removed. FIG. 7 (a) showing a partial cross-sectional view of the package after the encapsulation in the resin pool removing step, and FIG. 7 showing a partial cross-sectional view of the package after performing a gate break.
(B), FIG. 7 (c) showing a partial cross-sectional view of the package illustrating cutting of the resin reservoir 29, and FIG. 7 (d) showing a partial cross-sectional view of the package after cutting the resin reservoir 29. Then, the package after resin encapsulation is separated into individual packages by gate break, leaving a resin reservoir 29 (FIGS. 7A and 7B). The resin reservoir 29 is shot down with a punch 30 to finish the product (FIGS. 7C and 7D). Although not shown in the figure, the tie bar 5 is cut at the same time.

[0013]

In the above-described conventional lead frame for a semiconductor device, when the semiconductor chip 21 mounted on the lead frame 1 is sealed with a resin, the resin sealed in the package cavity 25 is filled with the lead frame 1. A resin flow hole 8 is provided as a means for injecting the resin from both upper and lower surfaces. Therefore, a resin reservoir 29 is formed in the resin flow hole 8 after the resin is filled.
The resin reservoir 29 is not necessary as a lead frame, and also causes the resin reservoir to come into contact with a transport jig during transportation in a later step, thereby stopping the flow of transportation.

Therefore, after the resin is sealed, the resin pool portion is shot down simultaneously with the cutting of the tie bar. At this time, the resin overflowing from the resin flow hole 8 comes into close contact with the resin flow hole 8 while sandwiching the peripheral edge thereof. ing. Since the adhesiveness between the lead frame 1 and the resin is good, as shown in FIG. 7E, even if the resin punch 29 is shot down with the forming punch 30, the resin reservoir 29 closely adheres to the lead frame corner of the peripheral portion of the resin flowing hole 8. Remains in a state where the peripheral part is bent with
Even if the remaining resin pool portion 29 is removed, the bent portion 31 of the peripheral portion remains as a burr-like projection, so that troubles such as a feeding error in the package transport in the post-process described above are likely to occur.

Further, cracks 32 or defective portions 33 are formed in the shot-down portions on the package side, and package defects often occur.

SUMMARY OF THE INVENTION An object of the present invention has been made in view of the above-mentioned drawbacks. In the step of removing a resin pool after resin sealing, no burr is formed on the periphery of the resin flow hole, and the resin pool is further removed. An object of the present invention is to provide a lead frame for a semiconductor device having a structure in which cracks on the package side and resin loss after knocking down are not generated.

[0017]

A feature of the lead frame for a semiconductor device according to the present invention is that a width of a suspension pin of a lead frame on which a semiconductor element is mounted is partially expanded, and an area including the expanded area and a corner area is provided. are opened in the lead frame for a semiconductor device having a resin flow holes for the uniform flow into the sealed resin on the upper and lower surfaces of the lead frame is sandwiched by the resin reservoir formed earlier SL resin flow holes encapsulated The peripheral metal
The cross-section provided around the peripheral portion has a V-shaped groove or a rectangular shape.
Along the slit row, the above resin in close contact is shot down
It has a structure .

[0018]

[0019]

[0020]

[0021]

The method of manufacturing a lead frame for a semiconductor device according to the present invention is characterized in that the width of a suspension pin of a lead frame on which a semiconductor element is mounted is partially expanded, and the resin flows into a region including the expanded region and a corner region. A method of manufacturing a lead frame for a semiconductor device, wherein a hole is opened so that an encapsulating resin flows evenly into the upper and lower surfaces of the lead frame. A peripheral portion of the resin flow hole formed in the corner region;
Predetermined shape of the slit or V-shaped groove <br/> opening process so as to surround the metal is included in one of the etching process or the pressing process, the opening process by the etching, the extension A first step of applying a resist to both front and back surfaces or one surface of the region, and using a pattern mask including a pattern for opening the slit, the corner region of the metal at the periphery of the flow hole ; wherein the second step of the two-sided or exposure and baking on the one surface of the slit Thomas other that the exposure and baking a third step of removing by developing the resist formation positions of the grooves , said the said slit enriched other exposed by developing the surface of the formation positions of the grooves, slits forming step or the one surface opened by etching to the back surface Consists of a fourth step consisting of a groove forming step of opening to the Luo predetermined depth, said opening step by the press working, punching for punching the corner area to the shape of the slit by a predetermined punch,
Or a groove that opens to a predetermined depth according to the shape of the groove
In any one of the cutting processes.

[0023]

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a plan view of a first embodiment of a semiconductor device lead frame according to the present invention. Referring to FIG. 1, a lead frame 1 includes an island 2 on which a semiconductor chip is mounted, an inner lead 3 connected to an electrode of the semiconductor chip by a bonding wire, and an outer lead 4.
A tie bar 5 between the inner lead 3 and the outer lead 4 for supporting these leads; a gate portion 5 where four outer corners are not provided with the outer leads 4; Pin 7
Is partially expanded, and is opened to a region including the expanded portion and the gate portion 5, and the opening of the gate portion 5 region has a predetermined size, and A fat flow hole 8 opened wider than the hole,
A groove-shaped opening (V notch) 9 is formed in the periphery by etching or pressing to surround the opening in the gate portion 5 region.

By providing the V-notch 9, the positions of the island 2 and the semiconductor chip in the package cavity are opened so that both sides of the lead frame 1 are uniformly filled with resin so as not to be displaced and deformed by the resin flow. As described above, a resin reservoir is formed in the resin flow hole 8 after the sealing. After being separated from other packages connected by a resin injection path by a gate break, the resin pool remaining in the resin flow hole 8 is shot down together with the tie bar 5 with a molding punch.

At this time, in the conventional lead frame without the V notch 9, when the resin pool portion, which is hardly inserted into the peripheral portion of the resin flowing hole 8, is shot down, the adhesion between the resin and the peripheral portion metal is good. The resin did not peel off, and the peripheral portion was also bent at the same time, and the peripheral portion remaining after the resin was removed was deformed into a burr shape.

Since the V-notch 9 is opened in advance to reduce the thickness of the lead frame in the notch, the V-notch 9 is cut down by the resin pool formed in the resin flow hole 8. The area (gap) 10 surrounded by the notch 9 can be shot down together.

Therefore, the peripheral portion is not deformed into a burr shape, and no extra pressure is applied to the connection portion of the resin reservoir 9 on the package side. Does not occur.

The above-described V notch 9 may be formed on any one of the front and back surfaces of the lead frame 1.

Referring to FIG. 2, which is a plan view of a second embodiment of the present invention, the difference from the first embodiment is that an etching process or a pressing process is performed in place of the V notch 9 in the first embodiment. That is, the slit 11 is opened by the processing. This slit 11 penetrates to the back surface of the lead frame 1, and the short slit 11 is inserted into the resin flow hole 7.
A plurality of openings are arranged in a line so as to surround the periphery of.

The other components are the same as those of the first embodiment, and the same components are denoted by the same reference numerals and description of the configuration will be omitted.

By providing the slit 11, the package in which the lead frame 1 is sealed with a resin is separated from other packages connected by a resin injection path by a gate break, and remains in the resin flowing hole 8. The resin pool is shot down together with the tie bar 5 with a forming punch.

At this time, as described above, the slit 11
In the conventional lead frame having no hole, the resin pool portion which was hardly inserted into the peripheral portion of the hole 7 deformed the peripheral portion into a burr-like shape. Is reduced, the gap 12 surrounded by the slit 11 can be shot down together with the shot down of the resin reservoir formed in the resin flow hole 8.

Therefore, similarly to the first embodiment, the peripheral portion is not deformed into a burr-like shape, and no extra pressure is applied to the connection portion of the resin reservoir 9 on the package side. No cracks or package defects occur on the side surfaces.

The above-described method for manufacturing a lead frame for a semiconductor device according to the present invention is a manufacturing process based on an etching process which is a normal lead frame forming process, and includes a process related to a slit and a V-notch portion before processing. FIG. 3 (a) showing a lead frame metal material in a sectional view, FIG. 3 (b) showing a resist coating in a sectional view, FIG. 3 (c) showing exposure and baking in a sectional view, and a sectional view of a developing process. (D), FIG. 3 (e) showing a cross-sectional view of the etching process, and FIG. 3 (f) showing the resist removal in a cross-sectional view. The steps are shown on the right side in comparison with the V-notch forming steps.

First, a resist 14 is applied to each of the front and back surfaces of the metal material 13 of the lead frame (FIG. 3A).
And (b)).

Next, the islands 2, inner leads 3, outer leads 4, tie bars 5,
Using a pattern mask 15 in which patterns for forming the V notches 9 and slits 11 of the present invention are formed in advance together with patterns necessary for forming the resin flow holes 8 and the like, exposure and printing are performed on both front and back surfaces or one surface of the metal material 13. (FIG. 3 (c)).

That is, the pattern mask 15 is a pattern mask applied to only one surface of the lead frame metal material 13 for opening a hole having a width of, for example, 50 μm to 500 μm in the case of the V notch 9. For example, it is a pattern mask to be applied to both surfaces for opening holes having a width of 50 μm to 500 μm.

Next, after removing the resist in the portion which has been previously exposed and baked by a developing process, the lead frame 1 in the portion where the resist has been removed beforehand is etched with a solvent comprising, for example, ferric chloride. Opening (slit) on both sides, or half etching (V notch)
I do. At this time, if the depth of the opening formed by etching the V notch 9 is at least about half the thickness of the lead frame, the gap between the resin pool and the gap 12 can be easily cut off (FIG. 3 ( d) and (e)).

Finally, the lead frame 1 having the V notch 9 and the slit 11 is obtained by removing the resist 14 from the entire surface of the lead frame 1 (FIG. 3).
(F).

On the other hand, FIG. 4A is a cross-sectional view of a lead frame metal material before press working in a manufacturing process using a press die, and FIG. 4B is a cross-sectional view of press work using a punch. FIG. 4 (c) showing the state of the press working in a sectional view, and FIG. 4 (d) showing the sectional view after the press working.
In this case, the slit forming step is shown on the left side and the V-notch forming step is shown on the right side in each case.

First, the metal material of the lead frame 13 is held by the forming die 16 and the holder 17 from above and below. In the case of the slit processing, the forming die 16 is formed with a mold according to the slit shape (FIGS. 4A and 4B).

Next, in the case of forming a slit, the unnecessary portion 20 is punched out by a punching punch 18, and in the case of forming a V notch, a groove is opened to a depth of at least about half of the lead frame thickness by a punch 19, thereby forming a V notch. A lead frame having a slit 9 and a slit 11 is obtained (FIGS. 4C and 4D).

In the two embodiments described above, the "C-shaped" slits and notches surrounding the periphery of the resin flow hole 8 are formed, but these may be "U-shaped".
In short, it is only necessary to have a shape that can be knocked down, and it is necessary to have a shape that can surround at least the vicinity of the curved peripheral portion vertex.

The width of the narrow gap 10 between the resin flow hole 7 surrounded by the V notch 9 and the narrow gap 12 surrounded by the slit 11 is larger than the width of the sealed resin protruding from the periphery of the resin flow hole 8. It is sufficient if the width is set in advance to be wide and at least a space of 0.1 mm width is opened.

[0046]

As described above, in the semiconductor device lead frame and the method of manufacturing the same according to the present invention, the width of the suspension pin is partially expanded, and the resin flow hole is formed in the area including the expanded area and the corner area. opening has been sealed resin is a lead frame so as to uniformly flow into the upper and lower surfaces of the lead frame, the opened slits so as to surround the resin flow hole peripheral portion or the peripheral tip near the corner area or, It has a notch dug at a predetermined depth, and a step of opening a slit or notch of such a predetermined shape is formed by being included in either a normal etching processing step or a pressing processing step. In a conventional lead frame without a notch, when the resin puddle that adheres so as to sandwich the periphery of the resin flow hole is shot down,
Because of the good adhesion of the resin, the resin was not easily peeled, and the peripheral portion was also bent. After the resin was removed, the resin remained in a burr shape. However, by previously opening the slit or notch of the present invention, the slit or notch is partially cut off by the plurality of slit portions, and the notch portion is thinner, so that the resin reservoir formed in the resin flow hole is formed. The area surrounded by the slit or the notch can be easily shot down together with the shot down.

Therefore, the peripheral portion is not deformed into a burr-like shape, and no extra pressure is applied to the connection portion of the resin reservoir portion on the package side. It is possible to provide a lid frame for a semiconductor device which does not cause any problem.

[Brief description of the drawings]

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

FIG. 2 is a plan view showing a lead frame according to a second embodiment of the present invention.

FIG. 3A is a cross-sectional view showing a lead frame metal material before etching in a process relating to a slit and a V-notch portion. FIG. 2B is a cross-sectional view illustrating resist application. (C) is a sectional view showing exposure and printing. FIG. 4D is a cross-sectional view illustrating the developing process. (E) is a sectional view showing an etching process. FIG. 4F is a cross-sectional view showing the removal of the resist.

FIG. 4A is a cross-sectional view showing a lead frame metal material before press working in a process relating to a slit and a V-notch portion. (B) It is sectional drawing which showed the press work by a punch. (C) It is sectional drawing which showed the state of press working. (D) is a sectional view showing a state after press working.

FIG. 5A is a plan view showing an example of a conventional lead frame having resin flow holes. (B) It is a top view of the lead frame after resin encapsulation.

FIG. 6A is a cross-sectional view of a main part of a lead frame before encapsulation, in a step of sealing a conventional lead frame with a resin. FIG. 4B is a cross-sectional view illustrating a resin encapsulation start state. FIG. 3C is a cross-sectional view showing a state after resin sealing. (D) is a cross-sectional view showing a state in which the package after encapsulation is separated into individual packages by a break.

FIG. 7A is a partial cross-sectional view of the package after the encapsulation in the resin pool removing step. FIG. 2B is a partial cross-sectional view of the package after performing a gate break. FIG. 3C is a partial cross-sectional view of the package for explaining the cutting of the resin reservoir. FIG. 4D is a partial cross-sectional view of the package after cutting the resin reservoir. FIG. 5E is a partial cross-sectional view of an example of the defective package at the time of removing the resin reservoir.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 lead frame 2 island 3 inner lead 4 outer lead 5 tie bar 6 gate section 7 suspension pin 8 resin flow hole 9 V notch 10 gap between V notch and resin flow hole 11 slit 12 gap between slit and resin flow hole 13 lid frame Metal material 14 resist 15 pattern mask 16a, 16b forming die 17a punching punch 17b punch 18 punched unnecessary portion 21 semiconductor chip 22 wire 23 lower die 24 upper die 25 cavity 26 cull portion 27 resin input portion 28,30 forming punch 29 Resin pool part 31 Bent part 32 Crack 33 Missing part

Claims (2)

(57) [Claims] 1. A width of a suspension pin of a lead frame on which a semiconductor element is mounted is partially expanded, and an opening is opened in a region including the expanded region and a corner region so that an encapsulating resin flows uniformly into the upper and lower surfaces of the lead frame. the lead frame for a semiconductor device having a resin flow hole for the resin reservoir portion formed in earlier SL resin flow holes sealed
The peripheral metal sandwiched by
V-shaped groove or square slit array provided so as to surround it
Has a structure to drop down the resin together in close contact along
Lead frame for a semiconductor device, characterized in that that. 2. The width of a suspension pin of a lead frame on which a semiconductor element is mounted is partially expanded, and a resin flow hole is opened in a region including the expanded region and a corner region, so that a sealing resin is formed on upper and lower surfaces of the lead frame. A method of manufacturing a lead frame for a semiconductor device formed by either an etching process or a press process; wherein the resin flowing hole formed in the corner region is provided. An opening step of a slit or a V-shaped groove having a predetermined shape so as to surround a peripheral portion of the expansion area is included in either the etching step or the press processing step. Includes a first step of applying a resist on both sides or one side, and a pattern for opening the slit A second step of exposing and printing the both sides or the one side of the corner area of the peripheral portion of the flow hole using the patterned mask, and the slit or the groove subjected to the exposure and printing A third step of developing and removing the resist at the formation location, and a slit formation step of opening the surface of the formation location of the slit or the groove exposed by the development to the back surface by etching or from the one surface. A fourth step including a groove forming step of opening to a predetermined depth, wherein the opening step by the press working includes:
A punching process of punching the corner region in accordance with the shape of the slit by a predetermined punching punch, or a cutting process of a groove opening to a predetermined depth in accordance with the shape of the groove. Of manufacturing a semiconductor device lead frame.