JP3144040B2 - Semiconductor device manufacturing method and device, and lead frame - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has a semiconductor chip mounted thereon and a plurality of outer leads led out from the periphery of a package in which the semiconductor chip is sealed into a desired shape while maintaining a predetermined interval. The present invention relates to a method for manufacturing a semiconductor device, and a device and a lead frame suitable for lead molding.

[0002]

2. Description of the Related Art A conventional method for manufacturing a semiconductor device, the device, and a lead frame will be described with reference to FIGS. FIG. 9 is a partial top perspective view showing a state where a lead frame in which a semiconductor chip is packaged is mounted on a forming die of a conventional forming die. FIG. 10 is a lead frame in a state shown in FIG. FIG. 11 is a partial cross-sectional view showing a state immediately before molding with a forming punch, and FIG. 11 is a partial cross-sectional view showing a state in which a lead frame is molded with a forming punch from the state shown in FIG. FIG. 14 is a top perspective view showing a state of a formed lead frame on a forming die, and FIG. 14 is a plan view showing a prior art lead frame.

First, the prior art lead frame will be described. The prior art lead frame 1 shown in FIG.
It is used in a normal QFP type semiconductor device, and has a square die pad 2 in the center, a plurality of inner leads 3 formed along each side of the die pad 2, A plurality of outer leads 4 formed corresponding to the leads 3 and four suspensions 8 formed at four corners 6A, 6B, 6C and 6D of the die pad 2 for connecting and supporting the die pad 2 to a frame 7
A, 8B, 8C and 8D. Reference numerals 9A, 9B, 9C, and 9D denote stays and reference numeral 10B
And 10D are section bars provided between the unit lead frames 1, and 11A and 11D.
C is an elongated hole formed over the width of the series of outer leads 4 between the stays 9A and 9C and the frame 7.

[0004] Such a lead frame 1 is usually manufactured by chemically etching a single strip-shaped conductive metal plate such as an iron-nickel alloy (42% by weight of nickel) or a copper alloy. Although only one lead frame is shown in FIG. 14, usually, a plurality of such unit lead frames 1 are formed on one conductive metal plate.
Usually, the thickness of the conductive metal plate is about 0.125 mm, the width of the outer leads 4 is about 0.12 to 0.4 mm, and the pitch of the outer leads 4 is about 0.3 to 1.27 mm.

A semiconductor chip (not shown) is fixed to the die pad 2 of the lead frame 1 having such a structure, and this semiconductor chip and the like are sealed with a ceramic package P as shown in FIG. Alternatively, a semi-finished product (hereinafter, simply referred to as "semi-finished product") S of a semiconductor device sealed with a resin package P by molding with a molten resin such as an epoxy resin by a transfer molding method. I have.

[0006] This single semi-finished product S is stamped from the single conductive metal plate.
The cutting of the tie bar 5, the deburring of the sealing resin, and the cutting of the frame 7 shown in FIG. 14 are performed. Therefore, the inner lead 3 existing at the base of the package P
Are formed in the outer leads in a state where they are separated from each other in a continuous form with the outer leads 4 respectively corresponding to the outer ends of the outer leads 4. However, the tips of the outer leads 4 are connected to the stays 9A, 9B. , 9C, and 9D.

As shown in FIGS. 9 and 10, such a semi-finished product S is formed into a forming die 2 of a forming die.
0 is placed at a predetermined position. This forming die 20
A package receiver 22 and a pillow-shaped lead receiver 23 and an outer lead molding surface 24 are formed at the center of the upper surface of the package receiver 22 so as to surround four sides of the package receiver 22. Accordingly, the package P of the semi-finished product S is fitted into the package receiver 22, and the outer leads 4 are placed on the respective lead receivers 23.

While maintaining this state, as shown in FIG. 10, the forming punch 21 and the knockout 2
5 is brought above the semi-finished product S, and the package P and the outer lead 4 of the semi-finished product S are pressed by the knockout 25 into the package receiver 22 and the lead receiver 23, respectively.
Fix it.

When the forming punch 21 is lowered in such a fixed state, as shown in FIG. 11, the outer leads 4 are formed along the outer lead forming surface 24. FIG. 12 shows the molded state. Thereafter, by cutting the four stays 9A, 9B, 9C and 9D, a desired semiconductor device is obtained.

[0010]

At present, semiconductor devices are integrated at a high density. Therefore, each of a plurality of inner leads and outer leads of a lead frame on which a semiconductor chip is mounted is thin, and 0.3-0.5
The fine pitch has come to be like the pitch of mm.

Such a lead frame 1 is usually manufactured by chemical etching. At this time, as shown in FIG. 13, upper and lower etching masks 30 and 31 are used.
9, the outer lead 4 having a regular quadrangular cross section is not formed.
12 to 12, since the stays 9A, 9C, 9B, and 9D connecting the distal ends of the outer leads 4 are not fixed, the outer leads 4 are horizontally moved when the outer leads 4 are formed. Moving, so-called lead flow occurs.

Further, even if there is a variation in the amount of burrs on the left and right of the lead generated when the tie bar 5 is cut, the lead flow similarly occurs.

[0013] As described above, bending and molding the lead into a predetermined shape while maintaining a predetermined interval requires an extremely advanced technique. If the leads cannot be formed in a predetermined shape while maintaining a predetermined interval, the leads may be defectively formed. Must be disposed of. An object of the present invention is to form the outer leads into a predetermined shape while maintaining a predetermined interval without causing such a lead flow or the like.

[0014]

Therefore, in the present invention,
Mounting the semiconductor chip, mounting the lead frame which is connected in a state where the top portion is aligned in the plurality of outer leads being led out from the periphery of the package is sealed and the semiconductor chip forming mold, and fixed, the Forming
A part of the mold, located at the tip of the outer lead.
Part of the stay in the bending direction of the outer lead.
Has a gap, but the gap is almost perpendicular to the bending direction.
The outer lead is formed into a desired shape with the forming die while guiding the lead to prevent the lead frame from moving in the orthogonal direction .

Further, the forming mold is composed of a Fomin <br/> Gupanchi and shaping die, these Four
Of the outer part of the forming punch or forming die
A guide means is provided at the position, and the guide means
Of the stay located at the tip of the outer lead
There is a gap in the bending direction of the outer lead,
Guide so that there is almost no gap in the direction perpendicular to the bending direction
The outer leads are formed by using a semiconductor device manufacturing apparatus configured as described above.

[0016]

Therefore, the guide means formed on the forming mold is extremely small in the direction perpendicular to the bending direction of the outer lead.
There is only a small gap and there is no room to move in the orthogonal direction
Since almost no, this the time of the outer lead molding, the stay connecting the respective distal end portion of the outer lead is held
As a result, the flow of the leads can be prevented.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A method for manufacturing a semiconductor device according to the present invention, a device therefor, and a lead frame will be described below with reference to FIGS. In these descriptions, QFP is used as a semiconductor device.
The present invention is not limited to a semiconductor device in which outer leads are led out of four sides of a package, such as a QFP type, but is described as an example. It is needless to say that the present invention can also be applied to a semiconductor device in which the outer leads are derived from the semiconductor device or a semiconductor device in which the outer leads are derived from two sides of the package. The same components as those of the prior art shown in FIGS. 9 to 14 are denoted by the same reference numerals, and their description will be omitted.

First, a first embodiment will be described with reference to FIGS. FIG. 1 is a partial top perspective view showing a state where a lead frame on which a semiconductor chip is packaged is mounted on a forming die of a forming die of the present invention, and FIG. 2 is a lead frame in a state shown in FIG. FIG. 3 is a partial cross-sectional view showing a state immediately before molding with a forming punch, and FIG. 3 is a partial cross-sectional view showing a state in which a lead frame has been molded with a forming punch from the state shown in FIG. FIG. 5 is a top perspective view showing a state of the formed lead frame on the forming die of the present invention, and FIG. 5 is a plan view showing the lead frame of the present invention.

The first embodiment of the present invention used in the first embodiment
FIG. 5 shows one of the lead frames 1A. Most of the configuration of the lead frame 1A is the same as the configuration of the lead frame 1 shown in FIG. 14, and the different portion is the central portion of the stays 9A, 9C, 9B and 9D, and the slots 11A and 11C respectively. Section bars 10B and 10D
A notch guide hole 12A having a rectangular shape opened on the side,
12C, 12B and 12D.

These guides 12A, 12C, 12B and 12D may be formed by etching simultaneously with the etching of the die pad 2, the inner lead 3, the outer lead 4, and the like, and also cut the tie bar 5 later. It may be formed by punching at the same time.

On the other hand, as shown in FIG. 1, the forming dies 20A of the forming mold are provided with the guide holes 12A, 12C, and 12C at the center of the outer surfaces of the surfaces 26A, 26B, 26C and 26D of the respective sections. 12B and 1
The guide projection 27 which is narrower than the 2D opening width but almost the same width.
A, 27B, 27C and 27D are formed. The distance between the guide projections 27A and 27C and the guide projection 27B
The distance between the guide holes 12A and 12D is slightly longer than the distance between the guide holes 12A and 12C and the guide holes 12B and 12D of the lead frame 1A. The other package receiver 22, the lead receiver 23, the outer lead forming surface 24, and the like are formed on the forming die 20A in the same manner as the conventional forming die 20.

Next, as shown in FIGS. 1 and 2, the semi-finished product SA using the lead frame 1A is positioned by placing the package P on the package receiver 22 and the outer leads 4 on the lead receiver 23. And each stay 9
Guide holes 12A, 12C, 12 of A, 9C, 9B and 9D
B and 12D are guide projections 27A, 27B, 27C and 2
It is placed on the forming die 20A so as to fit into 7D.

When the semi-finished product SA is placed in this manner, a gap between the bottom of each of the guide holes 12A, 12B, 12C and 12D and each of the guide projections 27A, 27B, 27C and 27D is formed.
Due to the dimensions described above, there is a slight gap. However, each guide hole 12A, 12A
Openings of C, 12B and 12D and guide projections 27A, 27
There is very little clearance between the widths of B, 27C and 27D, so there is little room to move in their width direction.

In such a state, as shown in FIG.
Package P and outer lead 4 with knockout 25
While holding down, the forming punch 21 is lowered to form the outer lead 4 along the outer lead forming surface 24. During this molding, stays 9A, 9C, 9B and 9
D is the respective guide holes 12A, 12C, 12B and 1
Since the guide projections 27A, 27B, 27C, and 27D are fitted into the 2D, the guides 27A, 27B, 27C, and 27D can be guided only in the vertical direction without moving in the horizontal direction. be able to. Accordingly, the outer lead 4 can be formed into a desired shape while the lead flow seen in the prior art occurs only for the very small gap. FIG. 4 shows the molded state. After this, the four stays 9A, 9B, 9
By cutting C and 9D, a desired semiconductor device can be obtained.

In the lead frame 1A used in the first embodiment, the guide holes 12A, 12B, 12C and 12D are provided in the stays 9A, 9B, 9C and 9D, respectively.
When the widths of these stays 9A, 9B, 9C and 9D are narrow, the guide holes 12A, 12B, 12C and 12D cannot be provided. In particular, the width of the stays 9B and 9D is usually narrow, and the stays 9B and 9D have guide holes 12B and 12D, respectively.
In order to provide D, it is necessary to widen the interval between adjacent single lead frames. Such a wide spacing requires a correspondingly large amount of lead frame material, resulting in loss and high cost.

Therefore, it was invented in order to realize the object of the present invention that the lead frame was not processed at all and that the purpose of the present invention was realized by devising the forming die.
This is an embodiment of the invention. This second embodiment will be described with reference to FIG.

The forming die of this embodiment is shown as forming die 20B. This forming die 20
As the guide means for B, the outer surface 26 of the four side surfaces thereof
A pair of guide projections 27A, 27B, 27C, and 27D are formed at both ends of A, 26B, 26C, and 26D higher than the respective surfaces 26A, 26B, 26C, and 26D, and the pair of guide projections 27A, 27B are respectively formed. , 2
The intervals of 7C and 27D were configured to be extremely slightly larger than the lengths of the stays 9A, 9B, 9C and 9D of the lead frame 1, respectively. The package receiver 2 shown in FIG.
2. Needless to say, the lead receiving member 23, the outer lead forming surface 24, and the like are similarly formed on the forming die 20B.

Since the forming die 20B is configured as described above, as shown in FIG. 6A, each of the stays 9A, 9C, 9B and 9D of the semi-finished product S is connected to the pair of guide projections 27A, 27B, 27C and The semi-finished product S is placed on the forming die 20B so as to be fitted between 27D and 27D. Although not shown in this embodiment, the package P and each outer lead 4 are pressed by the knockout 25 as shown in FIG. When the forming punch 21 is pressed down, the outer lead 4 can be formed into a desired shape as shown in FIG. 6B.

At the time of molding, the stays 9A, 9B, 9C connecting the outer leads 4 of the semi-finished product S at equal intervals.
, And 9D are connected to the guide projections 27A, 27B, 2
Since the lead frame 1 is guided so as not to be shifted in the lateral direction at 7C and 27D, the lead frame 1 of the prior art can be formed with the same structure, and the lead flow, which is a disadvantage at the time of forming the outer lead 4, can be prevented. Can be.

In the second embodiment, the guide means is provided on the forming die side. However, the guide means may be provided on the forming punch. Example 3
7 is shown in FIG.

As shown, the forming punch 21
Forming surfaces 40A, 40B, 40 on the lower surface of the outer side of the four side surfaces of A
C and 40D (the molding surfaces 40C and 40D are not shown) are provided at both ends thereof with a pair of guide projections 41A and 4D, respectively.
1B, 41C and 41D (the guide projections 41C and 41D not shown) are connected to the respective molding surfaces 40A, 40D.
B, 40C and 40D so as to protrude downward, and each pair of guide projections 41A, 41B, 41C and 41
D is set to each of the stays 9A of the lead frame 1,
9B, 9C, and 9D were slightly opened from the length.

One of the forming dies of the forming mold has the same configuration as the prior art forming die 20 shown in FIGS.
A lead receiver 23, an outer lead molding surface 24, and the like are formed, and the semi-finished product S is similarly placed on the forming die 20.

Since the forming punch 21A is configured as described above, the semi-finished product S is placed on the forming die 20 as described with reference to FIG. 9, and is not shown in this embodiment. As shown, when the forming punch 21A is pressed down while holding the package P and each outer lead 4 with the knockout 25, the pair of guide projections 41A, 41B, 41C, and 41D cause the stays 9A, 9C, 9B, and 9D to move. While sandwiching both ends, each molding surface 40A, 40B, 40C, and 40D pushes down each outer lead 4 while each outer lead 4
Can be formed into a desired shape.

At the time of molding, the stays 9A, 9B, 9C connecting the outer leads 4 of the semi-finished product S at equal intervals.
And 9D are provided with the guide projections 41A, 41B, 4
Since the guides 1C and 41D are guided so as not to be displaced in the lateral direction, the lead frame 1 of the prior art can be formed with the same structure, and the lead flow, which is a drawback at the time of forming the outer leads 4, can be prevented. Can be.

FIG. 8 shows a fourth embodiment of the present invention. The forming punch 21B of this embodiment is similar to that of FIG.
In addition to the configuration of the forming punch 21A of the third embodiment shown in FIG. 3, the molding surfaces 40A, 40B, 40C and 4
0D (the molding surfaces 40C and 40D are also not shown in this figure) are each provided with one guide projection 42A,
42B, 42C and 42D (guide protrusions 42C and 42D
(Not shown), the respective molding surfaces 40A, 40A
B, 40C and 40D.
The protrusion amount is determined by the guide protrusions 41A, 41B, 41C and 41.
D is equal to the amount of protrusion.

The lead frame formed by this forming die has the guide holes 12A, 12C, 1 shown in FIG.
The outer lead 4 of the lead frame 1A is formed with a pair of guide projections 41A, 41B, 41C and 41D of the forming punch 21B.
A, 9C, 9B and 9D are sandwiched between the guide projections 42A, 42B, 42C and 42D.
A, 12C, 12B, and 12D.

If the projections of the guide projections 42A, 42B, 42C and 42D are made to project slightly longer than the projections of the guide projections 41A, 41B, 41C and 41D, when the forming punch 21B is lowered, each of the pair of projections is lowered. Each of the guide projections 41A, 41B, 41C and 41D is
Before sandwiching both ends of A, 9C, 9B, and 9D, the guide projections 42A, 42B, 42C, and 42D fit into the guide holes 12A, 12C, 12B, and 12D, respectively. And 9D can be easily positioned.

The forming die 20 has the same structure as that of the prior art shown in FIGS. 9 and 10, and the outer leads 4 are formed by these forming dies on the forming surfaces 26A and 26A.
The same applies to molding into a desired shape along 26B, 26C, and 26D, and a description thereof will be omitted.

[0039]

As described above, according to the present invention, the stay connecting the tips of the outer leads is held by the guide means formed on the forming mold when the outer leads are formed. Therefore, it is possible to prevent the flow of the leads, and thus to prevent the bending of the leads, which tends to occur when the outer leads are formed. Moreover, since the stays are also positioned by the guide means, when the semi-finished product is placed on the forming die, the centering of the package can be performed, and the variation in the outer lead shape due to the variation in the package size can be corrected. And many other excellent effects.

[Brief description of the drawings]

FIG. 1 is a partial top perspective view showing a state where a lead frame in which a semiconductor chip is packaged is mounted on a forming die of a forming die according to the present invention.

FIG. 2 is a partial cross-sectional view taken along line AA of FIG. 1, showing a state immediately before the lead frame in the state shown in FIG. 1 is formed by a forming punch.

FIG. 3 is a partial cross-sectional view taken along line AA of FIG. 4, showing a state in which a lead frame has been formed by a forming punch from the state shown in FIG. 2;

FIG. 4 is a top perspective view showing a state of a lead frame formed on a forming die of the present invention.

FIG. 5 is a plan view showing a lead frame of the present invention.

FIG. 6 is a second embodiment of the present invention, and FIG. A is a partial top view showing a state where a lead frame in which a semiconductor chip is packaged is mounted on a forming die of a forming die of the present invention; FIG. B is a top perspective view showing a state of a lead frame formed on a forming die.

FIG. 7 shows a third embodiment of the present invention, in which a lead frame on which a semiconductor chip is packaged is mounted on a forming die of a forming die of the present invention, and is not yet formed by a forming punch. FIG.

FIG. 8 shows a fourth embodiment of the present invention, in which a lead frame in which a semiconductor chip is packaged is mounted on a forming die of a forming die of the present invention, and is not yet formed by a forming punch. FIG.

FIG. 9 is a partial top perspective view showing a state where a lead frame in which a semiconductor chip is packaged is mounted on a forming die of a conventional forming mold.

10A shows a state immediately before the lead frame in the state shown in FIG. 9 is formed by a forming punch, and FIG.
FIG. 3 is a partial cross-sectional view taken along line A.

FIG. 11A shows a state in which a lead frame has been formed by a forming punch from the state shown in FIG. 10;
FIG. 3 is a partial cross-sectional view taken along line A.

FIG. 12 is a top perspective view showing a state of a lead frame formed on a forming die.

FIG. 13 is a partial cross-sectional view for explaining the shape of an outer lead.

FIG. 14 is a plan view showing a conventional lead frame.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Lead frame 1A Lead frame 2 Die pad 3 Inner lead 4 Outer lead 5 Tie bar 7 Frame 9A Stay 9B Stay 9C Stay 9D Stay 12A Guide hole 12B Guide hole 12C Guide hole 12D Guide hole 20 Forming die 20A Forming die 20B Forming die Reference Signs List 21A Forming punch 21B Forming punch 22 Package receiver 23 Lead receiver 24 Outer lead molding surface 25 Knockout 26A Molding surface 26B Molding surface 26C Molding surface 26D Molding surface 27A Guide projection 27B Guide projection 27C Guide projection 27D Guide projection 40A Mold surface 40B Forming surface 40D Forming surface 41A Guide protrusion 41B Guide protrusion 41C Guide protrusion 41D Guide protrusion 42 A Guide projection 42B Guide projection 42C Guide projection 42D Guide projection S Semi-finished product SA Semi-finished product P Package

Claims (3)

(57) [Claims] 1. A lead frame on which a semiconductor chip is mounted and a plurality of outer leads led out from a peripheral edge of a package in which the semiconductor chip is sealed are connected in a state where tips of the outer leads are aligned. Fix, and, in a part of the forming mold, the outer lead
Part of the stay located at the tip of the outer
There is a gap in the bending direction of the cable, but it is orthogonal to the bending direction.
The direction and guided so as not to substantially a gap, the straight tip portion of the lead frame by the guide
A method of manufacturing a semiconductor device, comprising forming the outer lead into a desired shape with the forming mold while holding the outer lead so as to prevent movement in the cross direction . 2. The forming die comprises a forming punch and a forming die, and the forming punch or the forming die is provided with a guide means at a predetermined position on an outer portion thereof .
The guide means positions the distal end of the outer lead.
Part of the stay to be placed
Direction, there is a gap in the direction orthogonal to the bending direction.
2. The apparatus for manufacturing a semiconductor device according to claim 1, wherein the apparatus is configured to be guided so as not to substantially occur . 3. A die pad, a plurality of inner leads formed at predetermined intervals along side edges of the die pad,
These multiple outer leads formed corresponding to the inner leads, these outer lead of the tip, such a stay linked by aligning the Rutotomoni, in place of the stay at hotel formed a guide means
The guide means forms the outer lead into a desired shape.
Depending on the forming die to be formed, the outer lead
There is a gap in the bending direction, but in the direction orthogonal to the bending direction
Is a lead frame configured to be guided so that a gap is not substantially generated .