JPS59175146A - Lead frame element material - Google Patents

Abstract

PURPOSE:To enable to discriminate the back and front and the right and left of the cut lead frame element material by forming so that only one of four guide holes at cutting positions is of a shape different from that of other holes, and that cutouts generate at corners of the element material after cutting. CONSTITUTION:Guide holes 6 for counting at cutting positions of one frame of the lead frame element material are formed, at every other line, as guide holes 63 of the form of note that are not symmetric right and left, whose left half is semi-circular and right one leads to the outer edge of the frame 1. After cutting, the hole is divided into a semi-circular recess 64 and a cutout 65. Semi-circular recesses 61, 62, and 64 are formed at three points of guide hole cutting parts at four corners, and the cutout parts 65 is formed only at a point. Therefore, the discrimination of the front and back and the right and left of this cutting element material is easy, and accordingly it comes proved whether the frames are stacked in a wrong direction or not based on the succession of the cutouts in one of the four corners even in the stacked state.

Description

Detailed description of the invention [Technical field to which the invention pertains] The present invention is manufactured as a long strip, and a predetermined number of unit lead frames are successively cut and divided from the long strip, followed by plating, It relates to lead frame materials on which operations such as mounting and bonding of elements are performed.

[Prior art and its problems]

FIG. 1 shows a typical IC lead frame material, which has a frame 1 on both sides, and an inner frame 10 consisting of an island portion 2 on which an IC pellet is mounted and a plurality of lead portions 3 is connected via connectors 4 and 5. and is supported by its frame 1. In both frames 1, counting guide holes 6 and feeding guide holes 7 are alternately formed at opposing positions in both frames. These lead frame materials are manufactured as long products by repeatedly punching and forming a metal strip using a press and winding it onto a reel. However, it is used in processes such as plating, element mounting, wire bonding, and sealing in semiconductor factories. It is not easy to work if the length is long, so for example 1
The lead frame is cut on the center line of the counting guide hole 6 so that lead frames of 0 units each can be processed at once. Figure 2 shows frame 1 after cutting for 3 units of lead frame.
Only the 0 part is shown, and the illustration of the frame interior 1o is omitted. That is, frame 1 shown enlarged in FIG.
is cut on the center line of the guide hole 6 as shown in FIG. 4, so semicircular recesses 61 and 62 are formed in the cut portion. The four parts 61 and 62 have exactly the same shape, so even if the inside of the frame 10 has an asymmetrical shape like a lead frame for an SIL package, the frame 1 can be used even if the front, back, left, and right sides are reversed. They cannot be easily distinguished, and when they are stacked and cannot be seen from the outside only from the side of the frame 1, they cannot be found from the outside even if there is something in the opposite direction.

Therefore, when working on stacked lead frames, devices were often mounted on the wrong side. In order to avoid this, a discrimination mark 8 or 9 is attached to one of the frames 1, as shown in FIGS. 5 and 6. However, such marks 8.9 are usually formed at the same time when the lead frame is punched out, so they are formed on the material at regular intervals. Therefore, it can be used to distinguish between front and back, but it is impossible to distinguish between left and right. Discrimination between front and back is performed by looking at the stacked cut lead frame materials from the stacking direction and checking whether the mark 8 can be seen as a continuous groove or the mark 9 can be seen as a hole penetrating the stack. If it does not look like this, it can be determined that there are items that have been stacked with the front and back reversed, but it is difficult to take out items that are oriented in the wrong direction from the stack.

[Purpose of the invention]

The present invention eliminates the above-mentioned drawbacks and makes it possible to distinguish the front, back, left, and right sides of lead frame materials cut into a plurality of continuous lead frame units, and even when stacked in the wrong direction. The purpose of the present invention is to provide lead frame materials that can be easily found and taken out at low cost and in a simple manner.

[Key points of the invention]

In the present invention, the guide holes at the cutting position of one frame are arranged at every other corner on the left and right so that only one of the cut parts of the guide holes at the four corners of the cut material has a shape that extends to the outer edge of the frame. The above object is achieved by being asymmetric and formed so that only one side of the center line passing in the width direction of the material opens to the outer edge of the frame. As an example, every other counting guide hole 6 at one cutting position of the frame of the lead frame material is not symmetrical, the left half is a semicircle, but the right half extends to the outer edge 11 of the frame 1. The guide hole 63 is formed in the shape of a musical note. Therefore, after cutting, it is divided into a semicircular recess 64 and a notch 65 as shown in FIG. FIG. 9 shows only the frames 1 of the lead frame material after cutting, and semicircular recesses 61, 62, and 64 are formed in three of the cut portions of the guide holes at the four corners, and only one is cut out. A portion 65 is formed. Therefore, it is easy to distinguish between the front, back, left, and right sides of the cut materials, and even when the materials are stacked, it is possible to determine whether or not there is a notch in one of the four corners that is stacked in the wrong direction. In addition, if you remove the item protruding from the notch, you will be removing the item in the wrong direction, making the process easier.

〔Effect of the invention〕

As described above, in the present invention, only one of the four guide holes at the cutting position has a different shape from the other holes, so that a notch is formed at the corner of the material after cutting. Table of cutting lead frame material.

This makes it easier to distinguish between the back, left, and right, as well as to take out incorrectly stacked materials. Since such a guide hole can be easily manufactured by changing the shape of a punching die, no special process is required and it can be obtained at low cost, and the effects of the present invention obtained are extremely large.

[Brief explanation of the drawing]

Fig. 1 is a plan view of an example of a conventional IC lead frame material, Fig. 2 is a plan view showing only both frames after cutting, and Fig. 3 is an enlarged plan view of a portion of the frame before cutting. 4 is an enlarged plan view after cutting, FIGS. 5 and 6 are enlarged plan views of a portion of a frame of another conventional example, and FIG. 7 is an enlarged plan view of a portion of a frame of an embodiment of the present invention. Enlarged plan view before cutting,
FIG. 8 is an enlarged plan view after cutting, and FIG. 9 is a plan view showing the state of the lead frame material after cutting only for both frames. 1...Lead frame frame, 6...Guide hole for counting, 6
1.62...Semicircular recess formed after cutting, 63...
Left and right asymmetrical guide hole, 64...Semicircular shape created after cutting
6- recess, 65 notch formed after cutting. -7- Sai 3 Sen-ra Ward Sai S Roya b Su Sai 10

Claims (1)

[Claims] 1) When cutting on the center line of the guide holes in both frames and dividing into equal lengths for subsequent work, every other guide hole in the cutting position of one frame is asymmetrical. A lead frame material characterized in that only one side of the center line running in the width direction of the material is open to the outer edge of the frame.