JPH05102205A - Lead frame - Google Patents

Abstract

PURPOSE:To contrive improvement both in working capability in a die-attaching process and in judgement of the mounting and fixing position of a chip by a method wherein a half-etching section is provided on the chip-mounting surface of a die pad. CONSTITUTION:Long and narrow half-etching sections 7a to 7d are provided along X-and Y-axes on an almost square-shaped die pad 1 to be used to mount an integrated circuit chips. In a die-attaching process, the center of the die pad 1 and the center of an integrated circuit chip 4 are judged by the eye measurement of the operator from the shape of the half-etching parts 7a to 7d, the X-axis and the Y-axis of the die pad 1 and the integrated circuit chip 4, which orthogonally intersect at the above-mentioned centers, are brought in coincidence with each other, and as a result, the position of the integrated circuit chip 4, which is placed and fixed on the die pad 1, can be determined. Accordingly, the judging period of the operator, namely, the period required for manufacture, can be cut down, and at the same time, the generation of short circuit between wires and between the wire and the die pad can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lead frame mainly used for external lead assembly of a resin-sealed semiconductor device.

[0002]

2. Description of the Related Art In assembling an integrated circuit using a lead frame, die attachment is carried out in which the integrated circuit chip is mounted and fixed on an integrated circuit chip mounting surface of the die pad with an adhesive.

FIG. 3 is a plan view of the die pad portion of the lead frame. In the figure, the die pad portion 1 is a flat plate, and the integrated circuit chip is mounted and fixed when die attachment is performed. The operator visually determines the center of the integrated circuit chip shape and the center of the die pad from the die pad shape, passes the respective two centers, and determines the X-axis and the Y-axis orthogonal to the center. It is decided by matching.

[0004]

In recent years, as the functions of semiconductor devices have increased, the demand for an increase in the number of input / output terminals of an integrated circuit has rapidly increased, and many semiconductor devices having more than 200 pins have been made.

In proportion to this, miniaturization of the pads provided on the integrated circuit chip is progressing, and the number of pins of the inner lead portion of the lead frame is increasing.

As a result, in the method of determining the mounting and fixing position of the integrated circuit chip in the die attach process according to the above-mentioned conventional technique, the X axis and the Y axis of the integrated circuit chip 4 do not match as shown in FIG. When it is mounted and fixed in the die attach process, the pad 6 on the integrated circuit chip is
The wires 3a and 3b, which are wire-bonded from a and 6b to the inner leads 5a and 5b, respectively intersect,
If the current flowing through the circuit is short-circuited or the integrated circuit chip 4 is placed and fixed while being offset toward a part of the integrated circuit chip mounting surface of the die pad 1 as shown in FIG.
The lengths of the wires 3c and 3d wire-bonded from the pads 6c and 6d on the integrated circuit chip to the inner leads 5c and 5d become longer than the standard, and the lead frame portion (die pad 1) of another potential as shown in FIG. There was a problem such as contact with. Therefore, it has been strongly desired to provide a lead frame for an integrated circuit, which can overcome the above problems and can quickly and surely recognize the die attach process.

[0007]

A lead frame according to the present invention comprises a substantially square die pad on which an integrated circuit chip is mounted, and an inner lead which is arranged on the periphery of the die pad and has one end facing the die pad. , The four quadrants separated by the X-axis and the Y-axis which are orthogonal to each other at the center on the integrated circuit chip mounting surface of the die pad are in the other quadrants with respect to the X-axis and the Y-axis. The half-etched portion is provided as described above.

[0008]

According to the present invention, the center of the die pad can be easily and accurately determined by providing the half-etched portion other than the outer shape of the die pad, which is a reference for determining the center of the die pad, on the chip mounting surface of the die pad. There was an effect that the work became quick and accurate in the process.

[0009]

Embodiments of the present invention will be described below with reference to FIGS.

FIG. 1 is a plan view of a die pad portion showing an embodiment of the present invention. A die pad 1 having a substantially rectangular shape for mounting an integrated circuit chip is supported by die pad suspension leads 2 at its four corners.

The die pad 1 having a substantially rectangular shape has two elongated half-etched portions 7 each extending along the X axis and the Y axis.
a to 7d are provided. This half etching part 7
a to 7d are provided at positions symmetrical with respect to the Y axis with respect to each other on the X axis, and with respect to each other with respect to each other on the Y axis. Further, the respective half-etched portions have the same shape, and the distances from the intersections of the X axis and the Y axis are all equal.

FIG. 2 is also a plan view of the die pad portion according to the embodiment of the present invention. On the substantially square die pad 1, X
One L-shaped half etching portion 8a to 8d is provided in each of the four quadrants divided by the axis and the Y axis. This half-etched part has an X-axis and a Y-axis, respectively.
It is provided in a symmetrical position with respect to the axis. The quadrangle formed by connecting the respective corners has the same shape as the quadrangle of the outer shape of the integrated circuit mounting surface of the die pad. Similar to the half-etched portions 8a-8d, the half-etched portions 9a-9d and 10a-10d are provided in each of the four quadrants divided by the X-axis and the Y-axis, and each one is provided in the X-axis and the Y-axis. It is provided in a symmetrical position with respect to. The quadrangle formed by connecting the corners of the respective half-etched portions has the same shape as the quadrangle of the outer shape of the integrated circuit mounting surface of the die pad.

In the die attach step of the present invention, the half-etched portions 7a to 7d, 8a to 8d and 9a are formed.
9d and 10a to 10d, the operator visually judges the center of the die pad 1 and the center of the integrated circuit chip 4, and the X-axis and the Y-axis of the die pad 1 and the integrated circuit chip 4 which are orthogonal to each other at these centers are determined. The positions of the integrated circuit chips 4 to be mounted and fixed on the die pad 1 are determined by matching the above.

[0014]

As described above, according to the present invention, on the die pad, in each of the four quadrants separated by the X axis and the Y axis, one half is symmetrical with respect to the X axis and the Y axis. By providing the etching portion, in the die attach step, the recognition time of the operator, that is, the manufacturing time is shortened, and at the same time, the position of the integrated circuit chip mounted and fixed on the die pad can be accurately determined. It has an excellent effect of preventing the occurrence of defects such as a short circuit and a short circuit between the wire and the die pad. (In the prior art, the deviation between the center of the die pad and the center of the integrated circuit chip is about 0.30 mm.
It became 5 mm. )

[Brief description of drawings]

FIG. 1 is a plan view of a die pad portion showing an embodiment of the present invention.

FIG. 2 is a plan view of a die pad portion showing another embodiment of the present invention.

FIG. 3 is a plan view of a die pad portion.

FIG. 4 is a plan view of a die pad portion showing an example of a conventional technique.

FIG. 5 is a plan view of a die pad portion showing another example of the conventional technique.

6 is a sectional view taken along line I-I in FIG.

[Explanation of symbols]

 1 Inner lead die pad part 2 Inner lead suspension part 3a to 3d Wire 4 Integrated circuit chip 5a to 5d Inner lead 6a to 6d Pad on integrated circuit chip 7a to 7d Half etching part 8a to 8d Half etching part 9a to 9d Half Etching part 10a to 10d Half etching part

Claims (1)

[Claims] 1. A lead frame constituted by a substantially rectangular die pad on which an integrated circuit chip is mounted, and an inner lead arranged on the periphery of the die pad and having one end facing the die pad, the integrated circuit chip mounting surface of the die pad. In the four quadrants separated by the X-axis and the Y-axis which are orthogonal to each other at the center, half-etched parts are provided so as to be in contrast with those in the other quadrants with respect to the X-axis and the Y-axis. Characteristic lead frame.