JP2924858B2 - Lead frame and manufacturing method thereof - 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 used for a semiconductor device and the like and a method for manufacturing the same.

[0002]

2. Description of the Related Art FIG. 8A is a plan view of a conventional lead frame. This is because a rectangular outer frame 21, internal leads 27 and 28 formed integrally with the outer frame 21 and located inside the outer frame 21, an island 23 inside the outer frame, and an island 23 It has a hanging pin 24 connecting the outer frame 21. On the island portion 23, a semiconductor element (not shown) is mounted. The pad 25 is electrically connected to the internal leads 27 and 28 by the conductive wire 22 and is sealed with a resin. Then, there is a portion connected to the pad 25 by the conductive wire 22 straddling another internal lead 28, for example, like the internal lead 27. At this time, if the conductive wire 22 contacts another internal lead 28, a short circuit occurs. To prevent this, as shown in FIG.
8 is subjected to dimple processing, and the conductive wire 22 passes over the concave portion 28a formed thereby. Thus, contact between the conductive wire 22 and the internal lead 28 is prevented.

By the way, in recent years, the density of semiconductor devices has been increased.
Due to the demand for higher speed, the number of bonding locations tends to increase and be dispersed. Particularly, in the case of a lead frame as shown in FIG.
Since it is located at a position away from the internal lead, the internal lead 30 needs to be extended. In this case, one end (upper end in the drawing) of the internal lead 31 is blocked by the internal lead 30 and cannot be connected to the outer frame 21 of the lead frame. Therefore, as shown in FIG. 9B, the bonding portion 31b is a free end and is not stable. If the dimple processing portion (recess) 31a is in contact with another member (casing or the like), that portion can serve as a support portion, but the angle of the inclined portion 31c formed by dimple processing is set to be constant. Since it is difficult to control, it becomes difficult to keep the bonding portion 31b in the same plane as the other internal leads 30. Since the position (height) of the bonding portion 31b is unstable, the bonding operation is troublesome and the reliability is reduced.

Therefore, Japanese Patent Application Laid-Open Nos. 61-230347 and 62-22466 propose a configuration in which an insulating connecting member such as a polyimide tape is attached to the tips of a plurality of internal leads. When this configuration is adopted, FIG.
As shown in (a) and (b), an insulating connecting member 29 is attached to the tip of the internal lead 31 to be dimple-processed, and the free ends of the plurality of internal leads 30 and 31 supported at one end are insulated. The position of the bonding portion 31b is stabilized by being bundled together by the connecting member 29. The work procedure is as follows.
After fixing the internal leads 30 and 31 to each other, dimple processing is performed.

[0005]

In the prior art, the free ends of a plurality of internal leads 30 and 31 which are supported at one end are fixed to each other. That is, originally unstable portions are fixed to each other, so that such a strong stability cannot be expected. Further, when the dimple-processed internal lead 31 is fixed to the non-dimple-processed internal lead 30, the internal lead 30 on the non-dimple-processed fixed side, which does not originally cause displacement or deformation,
There is a possibility that the position and the posture are deviated by the attaching work of the insulating connecting member 29. Then, internal lead 3
Both 0 and 31 cannot be corrected to an appropriate position, and the positions of the bonding portions 30a and 31b cannot be stabilized.

Further, when dimple processing is performed after the insulating connecting member 29 is adhered, the tip ends of the internal leads 30 and 31 are misaligned, so that the insulating connecting member 29 is peeled or twisted without sufficient bonding strength. The tip of the lead may be deformed.

Further, in the case where the internal lead 30 is extended around the island portion 23 for a long time, the extending internal lead 30 becomes a hindrance, and a suspending pin for connecting the island portion 23 to the outer frame 21 is provided. There are restrictions on the position and number of 24. Therefore, the hanging pin 24 cannot be arranged at the most efficient position in order to suppress the displacement and inclination of the island part 23, and the position of the island part 23 becomes unstable, and the island part 23 is inclined when being filled with resin. In some cases, the semiconductor element, the island portion 23, the conductive wire 22, and the like may be partially exposed. Then, the protection of each member becomes insufficient.

Accordingly, an object of the present invention is to stabilize the position (height) of the dimple-processed internal lead and maintain the position within the same plane, thereby improving the bonding property, and improving the island strength. To ensure reliable sealing.

[0009]

In order to achieve the above object, a lead frame according to the present invention comprises an outer frame, and both ends supporting inner leads having both ends substantially connected to the outer frame.
One end supporting the internal lead, one end of which is connected to the outer frame and the other end is a free end and is dimple-processed, and the other end of the one end supporting internal lead is fixed to the both ends supporting internal lead. And an insulating connecting member.

[0010] Thus, the tip (free end) of the dimple-processed one-end supporting internal lead is fixed to the both-end supporting internal lead fixed to the outer frame at both ends, and the same plane is maintained without displacement. And bonding property is improved.

Another feature of the lead frame of the present invention is that an outer frame, an island provided inside the outer frame, an inner lead having at least one end connected to the outer frame, and an outer frame. A hanging pin connected to the island, a dummy hanging pin having one end connected to the island and the other end being a free end and being subjected to dimple processing, and the other end of the dummy hanging pin being connected to the inside. And an insulating connecting member fixed to the lead. Thereby, the displacement and inclination of the island are suppressed.

In the method of manufacturing a lead frame, the insulating connecting member is attached after dimple processing is performed on the one-end supporting internal lead or the dummy hanging pin. Thereby, the adhesive surface of the insulating connecting member does not peel off or deform during dimple processing.

[0013]

Next, an embodiment of the present invention will be described in detail with reference to the drawings.

A first embodiment of the present invention is shown in FIG. The lead frame includes a rectangular outer frame 1 and an outer frame 1.
, A suspension pin 3 connecting the outer frame 1 to the island portion 2, an inner lead 4 located inside the outer frame 1, and an outer lead 16 extending to the outside of the outer frame 1. doing. The internal leads 4 are substantially at both ends (FIG. 1).
Upper and lower ends 5c and 5d are connected to the outer frame 1 at both ends, and the inner leads 5 are connected to each other. One end 6c is connected to the outer frame and the other end 6 is connected.
d is a free end and one end supporting internal lead 6. The one end supporting inner lead 6 is provided with a concave portion 6a by dimple processing. A semiconductor element (not shown) is mounted on the island portion 2, and the pad 8 and the internal lead 4 are wire-bonded by a conductive wire 7. Note that the both-end supporting internal lead 5 is provided with an extension 5a extending laterally (leftward in FIG. 1) from near one end (upper end in FIG. 1) 5c, and this is one of the bonding portions. .

When the internal lead at a remote position is wire-bonded, there is a place where the conductive wire extends beyond another internal lead located in the middle. For example, when the bonding portion 5 b of the both-end supporting internal lead 5 is wire-bonded to the pad 8, the conductive wire 7 straddles the one-end supporting internal lead 6. At this time, the conductive wire 7 is disposed so as to pass over the concave portion 6a formed by the dimple processing of the inner lead 6 supported at one end.

An insulative connecting member 9 is attached to one end 6c of the dimple-processed one-end supporting inner lead 6 which is not connected to the outer frame 1 and has a free end shape. It is fixed to the both-ends supporting inner lead 5 via the sex connecting member 9. One end support internal lead 6
Is a state in which a dimple processing portion (recess) 6a is located between the one end 6c connected to the outer frame 1 and the other end 6d to which the insulating connecting member 9 is attached.

Since the upper and lower ends of the inner lead 5 are connected to the outer frame at the upper and lower portions in FIG. 1, the inner lead 5 is firmly fixed so as not to be deformed or displaced. Since the one-end supporting inner lead 6 is fixed to the both-end supporting inner lead 5, the one-end supporting inner lead 6 is also stably held without deformation or displacement.

Next, a method of manufacturing the lead frame according to the present embodiment will be described in detail.

First, a thin metal plate (for example, a metal plate made of 42 alloy, copper, or the like) is pressed or etched to form a main body of the lead frame. The outer frame 1, the island portion 2, the suspension pins 3, and the internal leads 4 are all integrally formed. Each of the bonding portions 5b and 6b of the internal lead 4 shown in FIG. 2A is plated. In FIG. 2A, a portion where plating has been performed is indicated by a broken line. Next, as shown in FIG. 2B, dimple processing is applied to the suspension pin 3 for supporting the island portion 2 and the one-end supporting internal lead 6, and the island portion 2 and the concave portion (dimple-processed portion) 6 are formed.
a, 3a is caused to have a height difference. The dimple processing method is shown in detail in FIGS. One end of the processing part of the support inner lead 6 is sandwiched between the upper mold 14 and the lower mold 15 and pressed to form the lower mold 15.
The supporting inner lead 6 is pushed into the recess 15a at one end to form a concave portion 6a by dimple processing. At this time, as shown in FIG. 3D, the other end 6d and the bonding portion 6b are formed in the concave portion (the dimple-processed portion) 6d.
It is drawn toward a, and its planar length is reduced. The hanging pins 3 are also subjected to dimple processing in the same manner.

Then, an insulating connecting member 9 is attached, and a semiconductor element (not shown) is mounted on the island portion 2. Each of the bonding portions 5 b, 6 b of the pad 8 and the internal lead 4 is connected by using a conductive wire 7. Are wire bonded (see FIG. 2C).

In the case of mass production, as shown in FIG. 4, the above processing is performed in a state in which a large number of lead frames are connected, and the lead frame is cut off by a cutting line 10 shown by a dashed line. To complete.

The distal end (the other end 6d, the bonding portion 6b, etc.) of the one-end supporting internal lead 6 from the dimple processing portion (recess) 6a is supported by the both-end supporting internal lead 5 via the insulating connecting member 9. Will be. Further, the both-end supporting internal leads 5 are supported by the outer frame 1 of the lead frame at two places (both ends 5c, 5d), and are not easily deformed or displaced. Therefore, the position (height) and flatness of the bonding portion 6b are maintained.

In the above-mentioned manufacturing method, if the insulating connecting member 9 is pasted before the dimple processing, the supporting inner lead 6 at one end is displaced during the dimple processing, so that the insulating connecting member 9 is deformed or peeled off. In addition, the position (height) and flatness of the bonding portion 6b cannot be maintained.
Therefore, in the present embodiment, as described above, the insulating connecting member 9
After attaching, dimple processing is performed.

FIGS. 5A to 5D are enlarged views of another example of the mounting portion of the insulating connecting member 9 of the lead frame of the present invention. In order to improve the reliability of the fixing, it is better that the area to which the insulating connecting member 9 is adhered is larger, and that the closer the internal leads 5 and 6 that are fixed to each other are, the better. For this purpose, various shapes of internal leads can be employed as shown in FIG.

Next, a second embodiment of the present invention will be described. The same reference numerals are given to substantially the same configuration as the first embodiment, and the description will be omitted.

As shown in FIG. 6 (a), in this embodiment, the extension of the both-end supporting internal lead 11 is longer, so that the island 12 and the outer frame 1 are connected to the upper part of the island 12. Hanging pins cannot be formed.
Instead, a dummy suspension pin 13 is formed in which one end 13a is connected to the island portion 12 and the other end 13b is free end without being connected to the outer frame 1. Outer frame 1
When the number of suspension pins 3 connected to the
The strength to support 2 drops. Therefore, the dummy hanging pins 13
Is formed so as to extend to the portion where the insulating connecting member 9 is adhered near the one-end supporting internal lead 6, and the dummy hanging pin 13 is fixed to the both-end supporting internal lead 11 via the insulating connecting member 9. ing. Since both ends of the inner lead 11 are firmly supported by the outer frame 1 at two points (both ends 11a and 11b), the dummy suspension pins 13 are also stably supported, and the supporting force of the island 12 is supplemented. In this manner, the island portion 12 is supported, and, for example, even when the semiconductor sealing resin is sealed, the island portion 12 is not deformed or displaced.

In this embodiment, the dummy hanging pins 1
The inner lead 3 and the one-end supporting inner lead 6 are simultaneously fixed to the both-end supporting inner lead 11 by the insulating connecting member 9. The both-end supporting internal lead 11 has a bonding portion 11c.

Also in this embodiment, as shown in FIG.
The above processing can be performed in a state where a large number of lead frames are connected, and the lead frame can be completed by separating the lead frames along the cutting line 10.

FIGS. 7A to 7C are enlarged views of another example of the mounting portion of the insulating connecting member 9 for fixing the internal lead 4 and the dummy suspension pin 13. FIG. Again, the area to which the insulating connecting member 9 is attached is large, and the greater the proximity of each member to be fixed, the higher the reliability of fixing. For this purpose, various shapes of internal leads 4 and dummy suspension pins 13 can be employed as shown in FIG.

The insulating connecting member 9 is desirably a strong plate such as a composite material of glass and epoxy. However, if two or more sides of both internal leads to be attached are close to each other, polyimide is used. It is possible to use an adhesive tape such as

[0031]

As described above, according to the present invention,
When the internal lead is extended around the inside of the outer frame and the dimple-processed internal lead exists at a position wrapped around the internal lead, the bonding property of the dimple-processed internal lead can be improved. .

In addition, when the internal leads are extended for a long time, even if the number and positions of the suspension pins for supporting the island portion become insufficient, the dummy suspension pins are provided and the dummy suspension pins are firmly supported. Accordingly, the island portion is not inclined or displaced during processing such as sealing of the semiconductor element or the like, and defects such as exposure of the semiconductor element, the island, and the bonding wire can be suppressed.

Further, by applying the insulating connecting member after the dimple processing, it is possible to prevent the internal leads and the dummy suspension pins from being deformed and the insulating connecting member from peeling off during the processing.

[Brief description of the drawings]

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

FIG. 2 is an enlarged plan view showing a manufacturing process of the embodiment shown in FIG.

FIG. 3 is an enlarged side view showing a dimple processing step of the embodiment shown in FIG. 1;

FIG. 4 is a reduced plan view showing a manufacturing process in mass production of the embodiment shown in FIG. 1;

FIG. 5 is an enlarged plan view of a portion where the insulating connecting member of the embodiment shown in FIG. 1 is attached.

FIG. 6 is a plan view showing a second embodiment of the lead frame of the present invention, and a reduced plan view showing a manufacturing process in mass production thereof.

7 is an enlarged plan view of a portion where the insulating connecting member of the embodiment shown in FIG. 6 is attached.

FIG. 8 is a plan view showing a first conventional example of a lead frame and an enlarged side view of internal leads thereof.

FIG. 9 is a plan view showing a second conventional example of a lead frame, and an enlarged side view of its internal leads.

FIG. 10 is a plan view showing a third conventional example of a lead frame, and an enlarged side view of internal leads thereof.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Outer frame 2, 12 Island part 3 Hanging pin 3a Depression (bonding processing part) 4 Internal lead 5, 11 Both ends support internal lead 5a Extension part 5b, 11c Bonding part 5c, 5d, 11a, 11b Both ends 6 One end support inside Lead 6a Depressed portion (bonding processing portion) 6b Bonding portion 6c One end 6d Other end 7 Conductive wire 8 Pad 9 Insulating connecting member 10 Cutting line 13 Dummy suspension pin 13a One end 13b Other end 14 Upper die 15 Lower metal Mold 15a Recess 16 External lead

Claims (3)

(57) [Claims] 1. An outer frame, a both-end supporting inner lead having substantially both ends connected to the outer frame, and a dimple process having one end connected to the outer frame and the other end being a free end. A lead frame, comprising: an inner lead supported at one end; and an insulating connecting member for fixing the other end side of the inner lead at the one end to the inner lead supported at both ends. 2. An outer frame, an island provided inside the outer frame, an internal lead having at least one end connected to the outer frame, a suspending pin connected to the outer frame and the island, and one end. A dummy suspension pin that is connected to the island and the other end is a free end and has been subjected to dimple processing; and an insulating connecting member that fixes the other end of the dummy suspension pin to the internal lead. A lead frame, comprising: 3. The method for manufacturing a lead frame according to claim 1, wherein the insulating connecting member is attached after dimple processing is performed on the one end supporting internal lead or the dummy suspension pin.