JPH08227961A - Lead frame for semiconductor device and its manufacture - Google Patents

Abstract

PURPOSE: To provide a lead frame having a structure wherein burr is not gener ated in a hole circumferential edge part and cracks and chipping of resin do not take out at a package side when removing a resin accumulated part of resin fluid hole. CONSTITUTION: This lead frame has an island 2, an inner lead 3 connected to an electrode of a semiconductor chip by a wire, an outer lead 4, a tie bar 5 which is between the inner lead 3 and the outer lead 4 and holds the lead group, a gate part 6 which is a space wherein the outer lead 4 is not arranged in a corner part of four sides and a resin fluid hole 8 which is opened ranging over a partial extension part of a width of one of hanging pins 7 connected to a corner part and a region of the gate part 6. A V-notch 9 is opened by etching treatment or press processing treatment in a circumferential edge part to enclose an opening part of a region of the gate part 6. The part of a clearance 10 enclosed with the opening part is knocked down together with a resin accumulated part.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art In recent years, semiconductor devices have been improved in the degree of integration with the progress of fine processing technology, and have been used in a wide range of fields including industrial equipment and consumer equipment. It was Therefore, a semiconductor device including a package having a shape that is easy to use for each device such as miniaturization, thinning, and multi-pinning has been commercialized.

Among the package forms used for these semiconductor devices, resin-sealed DIP (dual in
-Line package) type, QFP (quad)
flat package) type and QUIIP (qu
ad in-line) type.

When constructing these packages,
A lead frame using a conductive metal material is used. For the lead frame, there are a method of punching a thin metal plate by press working to obtain a desired shape and a method of etching treatment. A semiconductor chip is mounted on the island of the lead frame, and the electrode and the inner lead arranged around the island are wire-bonded by using a fine metal wire (wire) to perform electrical connection,
A structure is adopted in which these are sealed with resin.

At the time of resin sealing as described above, a lead frame having a semiconductor device mounted therein is housed in a cavity formed in conformity with a predetermined package shape, and one side of a hanging pin of an island mounting the semiconductor device is accommodated. The resin is sealed from. In that case, one of the methods developed for uniformly encapsulating the resin on the upper and lower surfaces of the lead frame is to form a hole portion called a resin flow hole in a region including the hanging pin portion and the corner portion, and It is devised that the resin injected from the lower surface side also flows into the upper surface through the resin flow hole, and the resin is evenly injected into the upper and lower surfaces.

FIG. 5A shows a plan view of a lead frame of the example, FIG. 5B shows a plan view of the lead frame after resin encapsulation, and a step of sealing the lead frame with resin. 6A is a sectional view of the lead frame before encapsulation, FIG. 6B is a sectional view showing a resin encapsulation start state, and FIG. 6A is a sectional view showing a state after resin encapsulation.
FIG. 6C is a sectional view showing a state in which the package after encapsulation is separated into individual packages by a gate break.
Referring to (d) together, the lead frame 1 made of a conductive material is provided between the island 2, the inner lead 3, the outer lead 4, and between the inner lead 3 and the outer lead 4 to support these lead groups. The width of one of the tie bar 5, the gate portion 6 in the corner portion area, which is a space where the outer lead 4 is not arranged in the corner portions of the four sides, and the hanging pin 7 connected to the corner portion is partially expanded. , Its extension and gate 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.

Resin encapsulation is generally carried out simultaneously with a plurality of lead frames 1 each having a semiconductor chip 21 mounted thereon. That is, a plurality of lead frames are
Package lower mold 23 heated to a high temperature of ° to 180 ° C
And sandwiched between the upper mold 24, clamped with a mold press, and a flowable thermoplastic resin of 60-12
It is injected into the mold at a low pressure of 0 Kg / cm ² to transfer-mold the package.

At this time, the cavities 25 of the mold sandwiching both packages are connected by the resin inflow path, and the resin injection portion 27 is provided in the cull portion 26 provided in the middle portion thereof (the resin is injected ( 6 (a) and (b)).

The resin flow of the thermoplastic resin flows under the lead frame 1 in the resin inflow path due to the injection pressure, and the lead frame 1 comes from between the gaps between the inner leads 3 or between the gaps between the inner leads 3 and the die pad 2. Is also filled in the cavity 25 on the upper surface of the. At this time, the resin flow also flows into the upper surface of the lead frame 1 from the resin flow hole 8 described above, so that the cavity 25 is uniformly filled with the resin.

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

Outside the resin-sealed package, the outer lead 4, the tie bar 5, the gate portion 6 and the resin flow hole 8 portion, in which the inner lead 3 is extended, are exposed, and at the position of the resin flow hole 8. A resin reservoir portion 29 is formed on the upper and lower surfaces of the hole so as to protrude from the peripheral portion thereof (FIGS. 5B and 6D).

The above-mentioned resin reservoir portion 29 is an unnecessary portion as a package and therefore needs to be removed. In this resin puddle removal step, FIG. 7A is a partial cross-sectional view of the package after the encapsulation, and FIG. 7A is a partial cross-sectional view of the package after the gate break.
(B), FIG. 7 (c) showing a partial sectional view of the package for explaining the cutting of the resin reservoir 29, and FIG. 7 (d) showing a partial sectional view of the package after the resin reservoir 29 is cut. Then, the package after resin encapsulation is separated into individual packages by the gate break, and the resin reservoir 29 remains (FIGS. 7A and 7B). The resin reservoir 29 is punched down by the punch 30 to finish the product (FIGS. 7C and 7D). Although not shown in this figure, the tie bar 5 is also cut at the same time.

[0013]

In the conventional lead frame for a semiconductor device described above, when the semiconductor chip 21 mounted on the lead frame 1 is resin-sealed, the resin sealed in the package cavity 25 is used. The resin flow hole 8 is provided as means for injecting from both the upper surface side and the lower surface side. Therefore, the 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 the transport jig during transport in a subsequent process to stop the transport flow.

Therefore, after the resin is sealed, the tie bar is cut off and the resin pool portion is knocked down. At this time, the resin protruding from the resin flow hole 8 adheres to the resin flow hole 8 with the peripheral portion thereof being sandwiched. ing. Since the adhesion between the lead frame 1 and the resin is good, as shown in FIG. 7 (e), the resin reservoir portion 29 adheres to the lead frame corner portion of the peripheral edge portion of the resin flow hole 8 even if the molding punch 30 knocks it down. It remains with the peripheral part bent,
Even if the remaining resin reservoir 29 is removed, the bent portion 31 at the peripheral edge remains as a burr-shaped protrusion, and thus a problem such as an error in feeding the package during the post-process described above is likely to occur.

Further, in many cases, a crack 32 or a defective portion 33 is generated in the part that is knocked down on the package side, resulting in a package defect.

The object of the present invention was made in view of the above-mentioned drawbacks. In the step of removing the resin reservoir after resin sealing, burrs do not occur at the peripheral edge of the resin flow hole, and the resin reservoir is further removed. It is an object of the present invention to provide a lead frame for a semiconductor device having a structure that does not cause a crack on the package side and a loss of resin after the semiconductor chip is knocked down.

[0017]

A feature of a lead frame for a semiconductor device according to the present invention is that a width of a hanging pin of a lead frame on which a semiconductor element is mounted is partially expanded, and an area including an expanded area and a corner area is included. In a lead frame for a semiconductor device having a resin flow hole that is opened at the same time to allow the encapsulation resin to flow evenly into the upper and lower surfaces of the lead frame, a predetermined shape is provided so as to surround the peripheral edge of the resin flow hole formed in the corner area. To have a groove-shaped opening formed by the width and the depth.

Further, instead of the groove-shaped opening, it is possible to have a slit opened with a predetermined width so as to surround the periphery of the resin flow hole formed in the corner area.

Further, the slit-shaped or groove-shaped opening may be formed only in a partial area of the peripheral edge portion surrounding the tip of the resin flow hole formed in the corner area.

Furthermore, the slits may be opened in a single row by using one of etching and pressing.

Further, the groove-shaped opening is opened by using either one of a half etching process for etching to a depth of about half of the lead frame thickness and a press process for opening to a depth of about half by a punch. May be done.

A feature of the method for manufacturing a lead frame for a semiconductor device of the present invention is that the width of the hanging pin of the lead frame on which the semiconductor element is mounted is partially expanded, and the resin flow is applied to a region including the expanded region and the corner region. A method of manufacturing a lead frame for a semiconductor device, which is a lead frame in which holes are opened to allow the encapsulating resin to flow evenly into the upper and lower surfaces of the lead frame and which is formed by either an etching process or a press process. A step of opening a slit or a groove-shaped opening having a predetermined shape so as to surround the periphery of the resin flow hole formed in the corner area is included in either the etching step or the pressing step, In the opening step by etching, a resist is applied to both front and back surfaces or one surface of the extension region. And a second step of exposing and baking the both surfaces or the one surface of the corner area of the flow hole peripheral portion using a pattern mask including a pattern for opening the slits, A third step of developing and removing the resist at the exposed or baked slit-shaped or groove-shaped opening forming portion, and the slit-shaped or groove-shaped opening exposed by the development The fourth step comprises a slit forming step of opening the front surface of the forming portion to the back surface by etching or a groove forming step of opening the one surface to a predetermined depth. A punching process for punching the corner area according to the shape of the slit by a punching punch, or the shape of the groove-shaped opening. Lies in comprising any one of the steps of the grooved rebated to open to a predetermined depth together.

[0023]

Embodiments of the present invention will now 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 lead groups, a gate portion 5 which is a region where the outer lead 4 is not arranged in the corner portion of the four sides, and a suspension connected to the corner portion. Pin 7
One of the widths is partially expanded and opened in 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 the width of the extended region of the hanging pin 6 is increased. Has a fat flow hole 8 that is wider than the hole,
A groove-shaped opening (V notch) 9 formed by etching or pressing is formed in the peripheral edge so as to surround the opening in the region of the gate portion 5.

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 surfaces 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, the resin flow hole 8 is provided with the resin reservoir portion after the sealing. After separating from the other packages connected by the resin injection path by the gate break, the resin reservoir remaining in the resin flow hole 8 is knocked down by the molding punch together with the tie bar 5.

At this time, in the conventional lead frame having no V-notch 9, when the resin pool portion which is hard to fill the peripheral portion of the resin flow hole 8 is blown off, the adhesion between the resin and the peripheral metal is good. The resin did not peel off, and the peripheral edge was also bent at the same time, and the residual peripheral edge was deformed into a burr even after the resin was removed.

Therefore, the thickness of the lead frame at the notch portion is made thin by opening the V notch 9 in advance, so that the V accommodating portion formed in the resin flow hole 8 is blown down. An area (gap) 10 surrounded by the notch 9 can also be shot down.

Therefore, since the peripheral edge portion is not deformed into a burr shape and no extra pressure is applied to the package side connection portion of the resin reservoir portion 9, a crack or a package defect is formed on the side surface portion of the package side which has been knocked down. Does not occur.

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

Referring to FIG. 2 which is a plan view of the second embodiment of the present invention, the difference from the first embodiment is that the V notch 9 in the first embodiment is replaced by an etching treatment or a press. That is, the slit 11 formed by the processing is opened. The slit 11 is penetrated to the back surface of the lead frame 1, and the short slit 11 is passed through the resin flow hole 7
A plurality of openings are arranged in a line so as to surround the periphery of the opening.

Since the other constituents are the same as those in the first embodiment, the same constituents are designated by the same reference numerals and the description of the structure will be omitted.

Due to the provision of the slits 11, the package in which the lead frame 1 is sealed with resin remains in the resin flow hole 8 after being separated from other packages connected by the resin injection path by the gate break. The resin pool and the tie bar 5 are shot down with a molding punch.

At this time, as described above, the slit 11
In a conventional lead frame without a hole, the resin pool portion that is hard to fit into the peripheral portion of the hole 7 deforms the peripheral portion into a burr shape. Since the gap is narrowed, the gap 12 surrounded by the slit 11 can be also shot down together with the shot down of the resin reservoir portion formed in the resin flow hole 8.

Therefore, as in the first embodiment, the peripheral edge portion is not deformed into a burr shape, and no extra pressure is applied to the package-side connecting portion of the resin reservoir portion 9, so that the package side is knocked down. No cracks or package defects occur on the side surface.

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

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

Next, an island 2, an inner lead 3, an outer lead 4, a tie bar 5, which are necessary for the lead frame 1,
Using the pattern mask 15 in which the pattern for forming the V notch 9 and the slit 11 of the present invention is formed together with the pattern necessary for forming the resin flow hole 8 and the like, exposure and baking are performed on both front and back surfaces or one surface of the metal material 13. (FIG. 3C).

That is, in the case of the V notch 9, the pattern mask 15 is a pattern mask applied to only one side of the lead frame metal material 13 for opening a hole having a width of, for example, 50 μm to 500 μm, and also in the case of the slit 11. , A pattern mask applied on both sides to open a hole having a width of, for example, 50 μm to 500 μm.

Next, after removing the resist of the portion which was previously exposed and baked by the developing treatment, the lead frame 1 of the portion which was previously subjected to the resist removing treatment is etched by a solvent such as ferric chloride. Opening (slit) on both front and back sides, or half etching (V notch)
To do. At this time, if the depth of the V notch 9 opened by etching is at least about half the thickness of the lead frame, it is easy to knock down the resin reservoir and the clearance 12 (FIG. 3 ( d) and (e)).

Finally, the resist 14 on the entire surface of the lead frame 1 is removed to obtain the lead frame 1 having the V notches 9 and the slits 11 (FIG. 3).
(F).

On the other hand, in a manufacturing process using a press die, a lead frame metal material before press working is shown in a sectional view of FIG. 4 (a), and a sectional view of press working by a punch is shown in FIG. 4 (b). 4C showing a cross-sectional view of the state of press working, and FIG. 4D showing a cross-sectional view after the press working.
Also in this case, in each case, the left side shows the slit forming step and the right side shows the V notch forming step.

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

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

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

Further, the width of the narrow gap 10 with the resin flow hole 7 surrounded by the V notch 9 and the width of the narrow gap 12 surrounded by the slit 11 are larger than the width of the enclosed resin protruding from the peripheral portion of the resin flow hole 8. It is sufficient if the width is preset and a space of at least 0.1 mm is opened.

[0046]

As described above, in the lead frame for a semiconductor device and the manufacturing method thereof according to the present invention, the width of the hanging pin is partially expanded, and the resin flow hole is formed in the area including the expanded area and the corner-free area. A lead frame which is opened to allow the encapsulating resin to evenly flow into the upper and lower surfaces of the lead frame, and which has a slit opened so as to surround the periphery of the resin flow hole in the corner region or the vicinity of the tip of the periphery, or a predetermined slit. Slits or notches are formed because they have notches dug at the depth of, and the process of opening slits or notches of these predetermined shapes is included in either the normal etching process or the press working process. With a conventional lead frame that does not have a
Due to the good adhesion of the resin, the resin was difficult to peel off and the peripheral portion was also bent, and remained in a burr-like shape after the resin was removed. However, by opening the slit or notch of the present invention in advance, the slit or notch is partially separated by the plurality of slit portions, and the notch portion is thin, so that the resin pool portion formed in the resin flow hole is formed. The area surrounded by the slits or notches can be easily removed together with the removal of.

Therefore, since the peripheral edge portion is not deformed into a burr shape and no extra pressure is applied to the package-side connecting portion of the resin reservoir portion, a crack or a package defect is formed on the packaged side surface portion. It is possible to provide a lid frame for a semiconductor device that does not occur.

[Brief description of drawings]

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

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

FIG. 3 (a) is a cross-sectional view showing a lead frame metal material before etching processing in a step related to a slit and a V notch portion. (B) It is sectional drawing which showed resist coating. (C) A cross-sectional view showing exposure and printing. FIG. 7D is a cross-sectional view showing the developing process. (E) It is sectional drawing which showed the etching process. (F) It is sectional drawing which showed resist removal.

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

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

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

FIG. 7 (a) is a partial cross-sectional view of the package after the resin puddle removal step and the encapsulation thereof. (B) It is a fragmentary sectional view of a package after performing a gate break. (C) It is a fragmentary sectional view of a package explaining cutting of a resin pool part. (D) It is a partial cross-sectional view of the package after cutting the resin reservoir. (E) It is a partial cross-sectional view of an example of a defective package at the time of removing a resin reservoir.

[Explanation of symbols]

 1 Lead Frame 2 Island 3 Inner Lead 4 Outer Lead 5 Tie Bar 6 Gate Part 7 Hanging Pin 8 Resin Flow Hole 9 V Notch 10 V Gap Between V Notch and Resin Flow Hole 11 Slit 12 Gap Between Slit and Resin Flow Hole 13 Led Frame Metal material 14 Resist 15 Pattern mask 16a, 16b Molding die 17a Punch punch 17b Punch 18 Unnecessary punched part 21 Semiconductor chip 22 Wire 23 Lower mold 24 Upper mold 25 Cavity 26 Cull part 27 Resin injection part 28, 30 Molding punch 29 Resin Reservoir Part 31 Bent Part 32 Crack 33 Missing Point

Claims (6)

[Claims] 1. A width of a hanging pin of a lead frame on which a semiconductor element is mounted is partially expanded, and an opening is made in a region including the expanded region and a corner region to allow the encapsulating resin to evenly flow into the upper and lower surfaces of the lead frame. In a lead frame for a semiconductor device having a resin flow hole for allowing the resin flow hole to have a groove-shaped opening formed with a predetermined width and depth so as to surround the periphery of the resin flow hole formed in the corner region. A lead frame for a semiconductor device, which is characterized in that 2. A slit having a predetermined width is provided instead of the groove-shaped opening so as to surround the periphery of the resin flow hole formed in the corner portion region. A lead frame for a semiconductor device as described above. 3. The slit-shaped or groove-shaped opening is formed only in a partial region of a peripheral portion surrounding the tip of the resin flow hole formed in the corner region. 2. The lead frame for a semiconductor device according to 2. 4. The lead frame for a semiconductor device according to claim 1, wherein a plurality of the slits are opened in one row by using one of an etching process and a press process. 5. The groove-shaped opening is formed by using either one of a half etching process for etching to a depth of about half of the lead frame thickness and a press process for opening to a depth of about half by a punch. The lead frame for a semiconductor device according to claim 2 or 3. 6. A width of a hanging pin of a lead frame on which a semiconductor element is mounted is partially expanded, a resin flow hole is opened in a region including the expansion region and a corner region, and encapsulating resin is formed on the upper and lower surfaces of the lead frame. In a method of manufacturing a lead frame for a semiconductor device, which is a lead frame that is made to uniformly flow into a corner of the resin flow hole, wherein the resin flow hole is formed in the corner region. A step of opening a slit or a groove-shaped opening having a predetermined shape so as to surround the periphery of is included in either the etching process or the pressing process, and the opening process by the etching is performed on both front and back surfaces of the expansion region. Alternatively, a first step of applying a resist on one surface and a pattern for opening the slit are included. Second step of exposing and baking the both surfaces or the one surface of the corner area of the flow hole peripheral edge portion using the patterned mask, and the slit shape or the groove shape exposed and baked. A third step of developing and removing the resist at the opening forming portion, and the surface of the slit-shaped or groove-shaped opening forming portion exposed by the development,
It comprises a fourth step consisting of a slit forming step of opening up to the back surface by etching or a groove forming step of opening up to a predetermined depth from the one surface. A semiconductor device, comprising either a punching process for punching the corner region according to the shape or a groove-shaped cutting process for opening to a predetermined depth according to the shape of the groove-shaped opening. For manufacturing lead frames for automobiles.