JPH066513Y2 - Lead frame for semiconductor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a structure of a semiconductor lead frame which requires a plurality of external leads for semiconductors such as transistors.

[Conventional technology]

Conventionally, this kind of semiconductor lead frame L has been disclosed in
As disclosed in Japanese Unexamined Patent Publication No. 2-69566 and shown in FIG. 8, three external leads L ₁ , L to the semiconductor element H are formed from one side edge of the elongated frame B at right angles to the longitudinal direction thereof. ₂ and L ₃ are projected, while the middle portions of the _three external leads L ₁ , L ₂ and L ₃ are connected by a tie bar F parallel to the longitudinal axis of the elongated frame B. Or, although not shown, on the left and right sides of the frame B,
Wherein similarly to the three external leads _{L 1,} L 2, while the protruded respectively _{L 3,} outer leads _L 1 of the _three, L 2, _{L 3}
It was usual that the middle part was shaped by a tie bar F so as to be connected in parallel with the longitudinal axis of the elongated frame B.

[Problems to be solved by the device]

In the technique disclosed in Japanese Patent Laid-Open No. 52-69566, press working is performed so that the tips of the external leads of the three-piece set are continuously installed so as to face each other, and then the continuous installation portion is cut off and press working. Then, the left and right frame frames B and B are separated.

Next, when manufacturing a semiconductor using this type of lead frame L, first, the semiconductor element H is die-bonded to the tip portion of the _one external lead L ₁ , and the semiconductor element H and the other two are connected. Wire bonding is performed between the ends of the external leads L ₂ and L ₃ .

After that, the lead frame L is sandwiched by a pair of upper and lower mold dies K, and the upper and lower mold dies K include these three external leads L ₁ and L including the semiconductor element H portion.
The cavities C for molding the tip end portions of L ₂ and L ₃ with synthetic resin are formed in a line at regular intervals, and thermoplastic synthesizing resin is injected into each of the cavities C to mold the cavities C. Also, the three external leads are cut and separated at the frame frame B so that the three external leads independently project from the synthetic resin mold portion M as shown in FIG.

As described above, during the semiconductor manufacturing process, each external lead L is
The work is concentrated on the tip portions of ₁ , L ₂ , and L ₃ .

However, in the lead frame L having the above-mentioned conventional shape, the tip portions of the outer leads L ₁ , L ₂ , and L ₃ are located farthest from the frame B, and the tip portions of the respective outer leads are so-called single-piece. Since it is a portion corresponding to the free end of the cantilever, it is easily deformed such as bending. When the lead frame L is unwound from a hoop-shaped one, the tip portions of the external leads are entangled with each other, There is a problem that the yield rate is low due to frequent occurrence of accidents such as the tips of the external leads coming into contact with other portions during the movement of the frame and the wire-bonded wires being broken.

In addition, the synthetic resin mold portion M is a lead frame L.
In the case where the cavities C are arranged in a line along the longitudinal direction, the arrangement density of the cavities C formed in the molding die K used in this molding process becomes considerably low, and as described above, the left and right sides of the frame B are left and right. In a molding die in which two rows of synthetic resin mold portions are provided apart from each other at both ends, the lateral direction of the molding die (in the width direction of the lead frame in the width direction of the lead frame is sandwiched so that this frame frame B is also sandwiched from above and below. (Corresponding) dimensions have to be set, so-called wasted portions increase, and it is impossible to increase the density of arrangement of cavities in spite of the increase in size of the molding die.

The present invention aims to solve the problems caused by the shape of the conventional lead frame.

[Means for Solving the Problems]

In order to achieve this object, the present invention is a first lead formed by punching external leads from a metal plate on one side edge of a long frame frame to form a set of a plurality of semiconductor elements at a constant pitch. A frame and a second lead frame which is formed by punching external leads for a semiconductor element, which is a set of a plurality of metal plates, from one side edge of a long frame similarly to form a fixed pitch on both sides of the frame. The outer leads of the frame are inwardly facing each other with their tip portions appropriately separated from each other, and the synthetic resin mold portions for the tip portions of the outer leads of each set are arranged in parallel so as to be aligned in the width direction of the lead frame, In addition, the midway length of each external lead is connected by a tie bar along the longitudinal direction of the frame frame, and the frame frames of both lead frames are connected to each other. It is obtained by integrally connected at connecting piece which is disposed at appropriate intervals along its longitudinal direction.

[Operation and effect of device]

According to this structure, the first lead frame formed by shaping the external leads for a set of a plurality of semiconductor elements on one side edge of the elongated frame at a constant pitch, and the second lead frame formed in the same manner. When the outer leads of both lead frames are arranged in parallel so as to face each other inward, the first lead frame and the second lead frame are arranged in a so-called left-right symmetry.

Furthermore, the longitudinal middle portions of the external leads are connected by tie bars along the longitudinal direction of the frame frame, and the elongated frame frames of the left and right first lead frames and the second lead frame are connected to each other in the longitudinal direction. Since the external leads are connected by a connecting piece that is perpendicular to the external leads, the external leads are surrounded by the rectangular frame in plan view formed by the pair of left and right frame frames and the connecting pieces. The parts are connected by a tie bar parallel to the frame.

Therefore, as compared to the conventional case where the external leads project like a cantilever from the long frame frame, each external lead is connected by a pair of left and right frame frames, a tie bar, and a connecting piece in the direction perpendicular to this. Not only the tip portion but also the tip portion of the outer lead is protected as a whole, and the chance that the tip portion of the external lead comes into contact with other things on the outside can be improved, thus improving safety.

In addition, the frame frames of the first and second lead frames are connected to each other by a connecting piece that is perpendicular to the longitudinal direction of the frame frame at each of a plurality of sets of intervals of the external leads with respect to the semiconductor element. Since the longitudinal middle portions of the external leads are connected by the parallel tie bars, the lead frame becomes rigid as a whole in a rectangular frame shape in plan view, and the external leads are less likely to be deformed such as an inconvenient curve. Further, it is possible to facilitate the die bonding and wire bonding work on the tip of the external lead of each set, reduce the occurrence of accidents such as wire cutting, and improve the yield rate.

Further, the tips of the outer leads protruding laterally from the frame frames of the first and second lead frames on the left and right sides are arranged so that the tips are spaced from each other by a predetermined distance. Since they are provided and the synthetic resin mold parts for the tips of the external leads of each set are arranged in parallel so as to be aligned in the width direction of the lead frame, the lateral direction of the molding die (long frame The cavities corresponding to the synthetic resin mold portion can be formed in two rows on the left and right without increasing the dimension in the direction perpendicular to the longitudinal axis of the frame).
This has the effect that a high-density molding die can be provided such that a common runner can be provided between the cavities in a row to simultaneously inject the synthetic resin into the cavities.

〔Example〕

Next, a description will be given of an embodiment. As shown in FIG. 1, a lead frame 1 formed by punching from a strip-shaped thin metal plate continuous in the up-down direction is provided with a semiconductor element on one side edge of a long frame 4a. External leads 5a, 6a, 7
The first lead frame 2 formed by molding a at a constant pitch (P) and the external leads 5b, 6b, 7b for the semiconductor element at a constant pitch (P) on one side edge of the elongated frame frame 4b. And a second lead frame 3 (see FIG. 1).

And 3 in the first and second lead frames 2 and 3
The central outer lead 5a, 5b of the set of outer leads
Each of the tip portions 8 is formed in a substantially T shape in a plan view, and the front and rear sides of the outer leads 5a and 5b at the center are provided with tip portions having a substantially L shape in a plan view so as to approach the tip portion 8. Leads 6a, 6b, 7a, 7b are arranged, and the outer leads of the first and second lead frames 2, 3 are arranged in parallel so as to face each other inwardly, and
In the embodiment, the outer leads 5a, 5b at the left and right sides are arranged so as to face each other with a predetermined gap such that the gap between the tips 8, 8 of the outer leads 5a, 5b is (H ₁ ). .

The frame frames 4a and 4b of the first and second lead frames 2 and 3 are integrally connected to each other by connecting pieces 9 arranged at appropriate intervals along the longitudinal direction.

And in the said Example, long frame frame 4a, 4
8 sets of connecting pieces 9 extending in the direction perpendicular to the longitudinal axis of b are arranged along the longitudinal direction of the frame (a total of 1 on both left and right sides).
6 sets) of external leads 5a, 5b, 6a, 6b, 7a, 7
Each frame b is integrally connected to the frame frames 4a and 4b.

Therefore, the lead frame 1 is composed of the first lead frame 2 and the second lead frame 3, the left and right outermost long frame frames 4a and 4b, and the connecting pieces 9 that horizontally connect the frame frames 4a and 4b. A plurality of sets of external leads 5a, 6a, 7a, 5b, which are formed in a rectangular frame shape, are formed in the frame space.
6b and 7b are arranged.

Note that reference numerals 10a and 10b denote elongated frame frames 4 in the first lead frame 2 and the second lead frame 3.
a tie bar extending parallel to a and 4b.
a is a middle part in the longitudinal direction of each of the external leads 5a, 6a, 7a and the connecting piece 9, and a tie bar 10b is a middle part in the longitudinal direction of the external leads 5b, 6b, 7b and the connecting piece 9.
By connecting each, the frame becomes strong,
Also, the bending of the external leads is reduced.

Further, reference numeral 11 is a feed hole formed in each of the frame frames 4a and 4b at the same pitch (P) as described above, and reference numeral 12
Is a recess formed in the outer surface of each frame 4a, 4b.

In the lead frame 1 of this configuration, as shown in FIG. 5, the outer portion of the center of the outer leads 5a, 6a, 7a and the outer leads 5b, 6b, 7b of the first lead frame 2 and the second lead frame 3 is set. After the semiconductor element 13 is die-bonded to the surfaces of the tips 8 of the leads 5a and 5b, the semiconductor element 13 and the external leads 6 on both sides of the semiconductor element 13 are bonded.
The tip ends of a, 7a and 6b, 7b are wire-bonded with a gold wire.

In this case, the pitch of the external leads of the three sets is the pitch (P) along the elongated frame frames 4a and 4b not only in the portion without the connecting piece 9 but also in the front and rear positions of the connecting piece 9.
Are the same, the mechanism for moving the lead frame 1 in the longitudinal direction for die bonding or wire bonding becomes simple.

Then, the middle part of each of the external leads in the longitudinal direction is
And the second lead frame are connected by tie bars extending in parallel to the longitudinal axis of the elongated frame frame, and the left and right pair of frame frames and the pair of frame frames are provided for each of a plurality of intervals of the outer lead. Since the tie bar is connected by a connecting piece parallel to the longitudinal direction of the external lead, the lead frame as a whole has a rectangular frame shape in plan view and is sturdy, and the external lead is less likely to be deformed such as an inconvenient curve. This has the effect of facilitating die bonding and wire bonding work on the tip of the external lead of each set, and eliminating the occurrence of accidents such as cutting of wires.

Further, since the portions to be die-bonded and the portions to be wire-bonded of the semiconductor element 13 are concentrated in the central portions on both right and left sides of the lead frame 1, the lead frame 1 is moved in the direction perpendicular to the longitudinal direction (lateral direction), Alternatively, there is no need to move the die bonding or wire bonding head largely, and the productivity is improved.

And the set of external leads 5a, 6a, 7a and 5
When the lead frame 1 is sandwiched by a pair of upper and lower mold dies 14 and 15 and a thermoplastic synthetic resin is injected into each cavity 16 in order to apply a synthetic resin mold to the tip portions of b, 6b and 7b. , A pair of left and right cavities 16, 16 can be formed adjacent to each other at positions close to the left and right central portions of the lead frame 1, while the left and right cavities 1
Since the runner 17 capable of simultaneously injecting the synthetic resin into 6 and 16 can be formed (see FIGS. 6 and 7), the molding die 1
It is possible to provide the molding dies having a high density by forming the dies 4, 15 compactly.

In other words, the tips of the external leads, which project inwardly and laterally from the elongated frame frames on both the left and right sides, are arranged so that the tips are separated by a predetermined distance. Cavity corresponding to the synthetic resin mold part is left and right 2 without increasing the lateral dimension of the mold (direction perpendicular to the longitudinal axis of the frame).
A mold die having a high density can be formed in rows, and a common runner for simultaneously injecting synthetic resin into the two cavities can be provided between the two cavities on the left and right. It also has the effect of being able to

[Brief description of drawings]

1 to 7 show an embodiment of the present invention, FIG. 1 is a plan view of a lead frame, FIG. 2 is a right side view, and FIG. 3 is an enlarged sectional view taken along line III-III of FIG. , Fig. 4 is IV of Fig. 1
-IV enlarged sectional view, FIG. 5 is an explanatory view of the operation, FIG. 6 is a perspective view of the molding die, FIG. 7 is a sectional view of the lead frame sandwiched by a pair of upper and lower molding dies, and FIG. FIG. 1 is a plan view of a conventional lead frame, and FIG. 9 is a perspective view of a synthetic resin molded semiconductor finished product. 1 ... Lead frame, 2 ... First lead frame, 3
...... Second lead frame, 4a, 4b …… Frame frame,
5a, 6a, 7a, 5b, 6b, 7b ... External lead,
10a, 10b ... tie bar, 9 ... connecting piece, 11 ...
Feed hole, 13 ... Semiconductor element, 14, 15 ... Mold die, 16 ... Cavity.

Claims (1)

[Scope of utility model registration request] 1. A first lead frame formed by punching external leads from a metal plate on one side edge of a long frame frame to form a set of a plurality of semiconductor elements at a constant pitch, and the same metal plate. And a second lead frame formed by punching external leads for a set of a plurality of semiconductor elements on one side edge of a long frame frame so as to be formed at a constant pitch. The tip portions are inwardly spaced apart from each other as appropriate, and the synthetic resin mold portions for the tip portions of the external leads of each set are arranged in parallel so as to be aligned in the width direction of the lead frame, and While connecting the longitudinal middle part with a tie bar along the longitudinal direction of the frame frame, between the frame frames of both lead frames,
A lead frame for a semiconductor, wherein the lead frames for a semiconductor are integrally connected by connecting pieces arranged at appropriate intervals along the longitudinal direction.