JP3054249B2 - Lead frame assembly - 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 assembly used for packaging a semiconductor integrated device.

[0002]

2. Description of the Related Art FIG. 3 is a structural view of a conventional lead frame assembly. Reference numeral 1 denotes a single metal component (a so-called lead frame) in which a number of leads (1a and 1b) are formed by punching, and a number of leads of the lead frame 1 are used for a power supply, a ground, and an input / output, respectively. Assigned for signals. Hereinafter, the lead 1a is used for ground, the lead 1b is used for power, and other leads (not shown) are used for input / output signals.

A lead 1a is provided with a first metal plate 2,
The second metal plate 3 is connected to the lead 1b, and is connected between all the leads and the second metal plate 3, and between the second metal plate 3 and the lead 1b.
Insulating resins 4 and 5 are interposed between the first metal plate 2 and the first metal plate 2. That is, the first metal plate 2, the insulating resin 4, the second metal plate 3, the insulating resin 5, and all the leads are sequentially laminated from the lower side to form an assembly called a so-called multilayer lead frame. By the way, the insulating resins 4 and 5
Usually, a resin tape in which an adhesive layer is formed on both sides is used. The recess formed by the first and second metal plates 2 and 3 and the insulating resins 4 and 5 is a cavity, and the chip 6 of the semiconductor integrated device is mounted in the cavity.

According to such a multilayer lead frame assembly, the chip 6 mounted in the cavity directly contacts the first metal plate 2, and the first metal plate 2 functions as a heat spreader (radiator plate). Therefore, heat dissipation can be improved. Also, a ground lead 1a and a power lead 1b
The power supply voltage transmitted by the first and second metal plates 2 and 3 can be distributed to a position very close to the chip 6, and the wire length of a minute cross section can be shortened to reduce the lead inductance of the power supply system. it can. this is,
This is an improvement in line characteristics. For example, a power supply system is effective in suppressing bounce noise.

[0005]

However, as in the above-mentioned conventional example, signals are transferred via a metal plate connected to a specific lead, thereby improving line characteristics. However, there is a problem that the effect of improving the line characteristics can be applied only to a very small number of signal types (about two types of grounds and power sources in the above-described conventional example) due to the limit of lamination of metal plates.

If the inner leads are extended in the direction of the chip 6, such a problem can be solved. However, since the distance between the inner leads becomes smaller as the inner leads are approached, there is a limit particularly in the case of a multi-pin lead frame. Therefore,
An object of the present invention is to improve the line characteristics of many signal types without being limited by the number of pins while improving heat dissipation.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a metal plate having a surface larger than a region surrounded by an inner end of an inner lead;
A shape made the wiring path through the layer, the metal plate及
And plating the inner wall of the through hole penetrating the insulating layer.
A predetermined wiring path and the metal
A plate is electrically connected to the inner lead , and an inner end of the inner lead is joined to an outer end of the wiring path.

[0008] In addition, preferably, a metallic plate, the ground layer
Alternatively, it is characterized by being used as a power supply layer .

[0009]

According to the present invention, the wiring path on the conductive film and the mounted chip are connected by a wire, that is, the chip and the inner lead are connected via the wire and the wiring path. Here, the wiring path is made precisely and freely by fine processing such as etching. Therefore, the line characteristics can be improved without being limited by the number of pins.

Further, since most of the strength can be borne by the metal plate, the thickness of the insulating material can be reduced, and the chip heat transmitted to the conductive film can be efficiently released to the metal plate.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 are views showing an embodiment of a lead frame assembly according to the present invention. In FIG. 1, a lead frame assembly 10 of the present embodiment is a single metal component 1 having a large number of leads 11a and 11b formed by punching.
1 (lead frame) and a chip mounting substrate 12 connected to the inner leads of the leads 11a and 11b.

The chip mounting substrate 12 is formed by attaching a copper foil 15 to one surface of a metal plate 13 via an insulating material 14 such as an insulating resin. On the copper foil 15 as the conductive film, a pattern is formed by etching. Each pattern is
Part 17 for mounting chip 16 of semiconductor integrated device
(Hereinafter, a chip mounting portion) and a large number of wiring paths (typically 18 to 22) are formed so as to have an optimal shape and an optimal route for each application. Here, a plurality of through holes 23 and 24 are formed in the metal plate 13. For example, a specific wiring path for ground and a metal plate are formed through the plating of the through holes and the back surface plating of the metal plate 13. 13 is electrically connected. In addition, 25 is a solder resist.

Next, the manufacturing process of the chip mounting substrate 12 will be described with reference to FIG. [Step of FIG. 2A] First, an insulating material 14 (preferably epoxy resin or polyimide resin) having heat resistance, insulation and adhesion (strength is not important) is provided on one surface of a metal plate 13. [Step of FIG. 2 (b)] Through holes (through holes) 23 and 24 are formed at predetermined positions. [Step of FIG. 2 (c)] Then, through holes 23 and 24
After plating the entire surface including the inner wall of the metal plate 13 and the back surface of the metal plate 13, the process shown in FIG.
The chip mounting portion 17 and a large number of wiring paths (typically 18 to
22), etc. [Step of FIG. 2 (e)] Finally, a solder resist 25 is applied to the back surface of the metal plate 13 to complete the process.

According to the lead frame assembly of the present embodiment having the above-described structure, (1) the holding strength of the chip 16 is mainly
, The insulating resin 14 can be made thinner,
The heat of the chip 16 transmitted to the copper foil 15 can be efficiently released to the metal plate 13. Therefore, heat dissipation can be improved. (2) Since the wiring path can be formed accurately and freely by etching the copper foil 15, even if the number of pins is large, the line characteristics can be improved without any trouble. (3) Since a specific wiring path is connected to the metal plate 13 by a through hole, the metal plate 13 can be used as, for example, a ground layer or a power supply layer. (4) Since a normal printed circuit board manufacturing process can be used, the cost can be reduced.

In the embodiment, the electrical connection between the wiring path and the metal plate is made by a through hole.
For example, a predetermined position of the insulating material 14 is cut out, and the wiring path (copper foil 15) and the metal plate 1 are directly cut through the cutout.
3 may be connected. In the embodiment, only the chip 16 is mounted on the chip mounting substrate 12, but the invention is not limited to this, and a circuit element such as a resistor may be mounted.

[0016]

According to the present invention, when a chip is mounted, a wiring path formed by etching can be interposed between the inner lead and the chip, so that the number of pins can be reduced while improving heat dissipation. The line characteristics of many signal types can be improved without limitation.

[Brief description of the drawings]

FIG. 1 is a structural diagram of one embodiment.

FIG. 2 is a manufacturing process diagram of the chip mounting substrate of one embodiment.

FIG. 3 is a structural view of a conventional example.

[Explanation of symbols]

 16: Chip 13: Metal plate 14: Insulating material 15: Copper foil (conductive film) 17: Chip mounting portion 18-22: Wiring path

Claims (2)

(57) [Claims] And 1. A metal having a large surface of the inner end portion surrounds the region of the inner lead plate, and a shape made the wiring path through the insulating layer <br/> on the surface of the metal plate, wherein Metal plate and
The inner wall of the through hole penetrating the insulating layer is plated to form
A predetermined wiring route and the metal plate
And an inner end of the inner lead and an outer end of the wiring path are joined. 2. The method according to claim 1, wherein the metal plate is a ground layer or a power supply layer.
Claim 1 lead frame assembly, wherein the use Te.