JPH05343596A - Lead frame and manufacture thereof - Google Patents

Abstract

PURPOSE:To effectively recognize an image of a cutout part and to facilitate positional correction of an inner lead side by providing a semicircular cutout part for the positional correction of the lead side on a die pad of a substantially square shape for placing an integrated circuit chip, and silver-plating the periphery of the cutout part. CONSTITUTION:A lead frame for a resin-sealed semiconductor device has a frame made of a rectangular frame, and many inner leads 5 extended from an inner wall of the frame 2 toward a die pad 3. Silver-plating 13a necessary when the leads 5 are connected to electrodes 12 of an integrated circuit chip 7 via wires is provided in the frame. A semicircular cutout part 11 to be used when the inner lead side is position-corrected is provided on the pad 3, and a periphery of the part 11 is also silver-plated 13b. Thus, an image of the part 11 is effectively recognized to prevent a malfunction of a bonding recognition.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lead frame for mounting an integrated circuit chip and a method for manufacturing the same.

[0002]

2. Description of the Related Art FIG. 1 is a schematic diagram for assembling a resin-sealed semiconductor device.
A lead frame as shown in is used.

The lead frame 1 has a frame frame 2 which is a distance frame, and has a distance die pad 3 on which an integrated circuit chip is mounted and fixed substantially at the center of the frame frame 2.

Further, the die pad 3 is supported on the frame 2 by a tie bar 4. Also, the frame 2
A number of thin leads 5 extend from the inner wall of the die toward the die pad 3, and each lead 5 is supported by a dam bar 6 that prevents resin from flowing out during resin molding.
The dam bar 6 also serves as a reinforcing member.

Further, particularly in a multi-pin lead frame having more than 100 pins, a semi-circular cutout portion 11 used for position recognition on the lead side is provided.

FIG. 2 is an enlarged view of the peripheral portion of the tie bar. The lead frame 1 is subjected to silver plating required when the inner lead 5 and each electrode 12 of the integrated circuit chip are connected using the wire 8. There are mainly the following two types of silver plating depending on the difference in the parts to be plated.

1) Die pad 3 and inner lead 5
Partial silver plating for plating the tip of the.

2) Ring silver plating for plating only the tips of the inner leads 5.

In ring silver plating, the die pad 3
Was not silver plated throughout.

[0010]

However, in the above-described conventional lead frame plated with ring silver, since the die pad 3 is not silver plated, the notch portion provided in the die pad 3 with the image recognition device. When recognizing the shape of and correcting the position on the internal lead side, the following problems have come to occur.

1) Since the material of the lead frame appears on the surface of the die pad 3 as it is, the position correction cannot be reliably performed due to the influence of linear stripes and crystal grains which are the characteristics of the material itself.

2) Therefore, if position correction is performed at the tips of the inner leads, the features of the inner lead 5 having a large number of pins are lost. The target internal lead 5 is erroneously recognized, and the internal lead other than the target is determined to be the recognition correction place, and the bonding is performed with a large displacement.

Accordingly, it is possible to provide a lead frame which overcomes the above problems and is capable of surely correcting the position of the inner lead side by recognizing the shape of the semicircular cutout portion provided in the die pad by the image recognition device. Was strongly desired.

[0014]

In a lead frame composed of a substantially rectangular die pad on which an integrated circuit chip is mounted and an inner lead arranged at the periphery of the die pad and having one end facing the die pad, in addition to the tip of the inner lead, And silver plating is applied to the periphery of the semicircular notch provided in the die pad.

[0015]

EXAMPLE An example of the present invention will be described below with reference to FIG.

In the plan view 1 of the conventional lead frame, after the lead frame 1 connects each electrode (not shown) of the integrated circuit chip 7 and the lead 5 by the wire 8,
The inner molding region 9 near the dam bar 6 is molded with resin to cover the integrated circuit chip 7, the wires 8 and the inner ends of the leads with the resin portion 10 of the semiconductor device. Further, the resin interposed between the outer periphery of the mold region 9 and the dam bar 6 is removed, the unnecessary dam bar 6 and frame frame 2 are cut and removed, and the outer ends of the protruding leads 5 are removed from the resin portion 10 of the semiconductor device. It is bent downward to manufacture a resin-sealed semiconductor device.

In the case of a multi-pin lead frame, the die pad 3 is provided with a semi-circular cutout 11 which is mainly used for position correction on the inner lead side.

FIG. 2 is an enlarged view of the periphery of the semicircular cutout 11 of FIG. 1. The shape of the semicircular cutout 11 is used to correct the position of the inner lead side during bonding. Image recognition is performed, and the reference image of the image recognition apparatus and the shift amounts ΔX and ΔY in the X and Y directions with respect to the reference position are calculated, and the bonding position of the entire inner lead is corrected.

By the way, in the silver plating execution step in the lead frame manufacturing process, the two plating shapes of the partial silver plating and the ring silver plating described in the prior art are generally used. Since the adhesiveness is not as good as the adhesion between the resin and the material, and the quality of the completed semiconductor device is remarkably deteriorated, the lead frame plated with ring silver is often used.

In using the lead frame plated with ring silver according to the present embodiment in the semiconductor device assembling process, the above-mentioned problems to be solved by the invention have been encountered.

FIG. 3 shows a range in which normal ring silver plating is applied, but silver plating 13 is not applied to any part of the die pad.

In this embodiment, as shown in FIG. 4, silver plating 13b is applied around the semi-circular cutout 11 provided in the die pad 3.

As a result, the shape of the semicircular cutout 11 can be reliably recognized in the position correction on the internal lead side during bonding.

In the present embodiment, the shape of the notch is described as an example of a semi-circular shape, but this shape may be any shape, and the shape of the plated portion around the notch is also notched. Any shape may be used as long as it has a range that does not hinder image recognition.

[0025]

As described above, according to the present invention, when the ring silver is plated on the lead frame, the periphery of the notch formed in the die pad portion is also silver-plated to ensure the image recognition of the notch. Since it is possible to prevent the occurrence of defective bonding recognition, there is an excellent effect that the working efficiency of the image recognition device and the operator is significantly improved.

[Brief description of drawings]

FIG. 1 is a plan view of a conventional lead frame.

FIG. 2 is an enlarged view of a main part of a conventional lead frame in FIG.

FIG. 3 is a diagram of a conventional lead frame plated with ring silver.

FIG. 4 is an explanatory diagram of an example of the present invention.

[Explanation of symbols]

 1 Lead Frame 2 Lead Frame Frame 3 Die Pad 4 Tie Bar 5 Lead 6 Dam Bar 7 Integrated Circuit Chip 8 Wire 9 Mold Area 10 Resin-sealed Semiconductor Device Resin Part 11 Notch 12 Integrated Circuit Chip Electrode 13a Silver Plated 13b Silver Plated

Claims (2)

[Claims] 1. A lead frame, comprising: a substantially square die pad on which an integrated circuit chip is mounted; and an inner lead disposed on the periphery of the die pad and having one end facing the die pad, in addition to the inner lead tip portion, A lead frame, characterized in that a silver plating is applied around a cutout portion provided in the die pad. 2. A lead frame constituted by a substantially square die pad on which an integrated circuit chip is mounted and an inner lead arranged at a peripheral edge of the die pad and having one end facing the die pad, wherein an opening of a plating mask is formed on the die pad. A method for manufacturing a lead frame, characterized in that the notch is provided and the tip of the inner lead is provided, and only that portion is silver-plated.