JPH0345543B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a semiconductor device, and particularly to a carrier for an integrated circuit.

<Conventional technology> A conventional dual-in-line package (hereinafter referred to as a DIP package) has a protrusion with a continuous surface extending from the side surface beyond the bottom surface, and the leads are connected to the DIP package. Some are formed so as to come out from the side surface of the DIP package, extend from the side surface of the protrusion along a ridge corresponding to the lower end of the protrusion, and extend toward the bottom surface of the DIP package.
With this configuration, the leads are supported and restrained by the protrusions. However, when soldering such a DIP package to a printed circuit board, etc.,
In a DIP package, the leads that pass through the ridges of the protrusions are soldered onto the printed circuit board, so solder flow tends to occur along the narrow gap between the ridges and the printed circuit board, causing the gaps between the leads. A short circuit accident may occur.

<Problems to be Solved by the Invention> The present invention has been made in view of the above points, and is capable of restraining and supporting the lead ends to be soldered and effectively preventing the solder flow as described above. The present invention provides a carrier for integrated circuits as described above.

<Means for Solving the Problems> According to the present invention, the integrated circuit carrier according to the present invention has a top surface 26, a bottom surface 28, and at least one side surface 35 extending from the top surface to the bottom surface. a plurality of ridges 5 extending from the sides beyond the bottom and separated from each other by gaps;
3, and a plurality of leads 43 each having one end located within the enclosure and a portion formed along one of the ridges.

<Operations and Effects of the Invention> In the present invention, a plurality of raised portions are formed on the bottom surface of the package cage and are separated from each other by a gap so as to extend from the side, and a lead is supported on each raised portion. Therefore, when the top of the raised part is butted against the printed circuit board and soldered using the solder ripping method, the wicking (solder flow) of the solder in that area is reduced, and the gap between the leads due to solder reflow is reduced. This prevents solder bridging.

Additionally, a ridge on the underside of the package that retains the leads allows the carrier to be easily attached to other devices during printed circuit board installation, socket insertion, inspection, or general handling. Deformation of the lead is kept to a minimum even when force is applied by contact with an object.

<Example> As shown in FIG. 1, the basic shape of the carrier 20 is a square. The carrier 20 has an enclosure 22 and a plurality of leads 24. The leads can be made of a conductive material, such as a copper alloy. Enclosure 22 may be made of plastic, such as epoxy. Carrier 20 may be of any suitable shape, but as shown in FIGS. 1, 2, and 3, it has a top surface 26, a bottom surface 28, and four sides 32-35, with The bottom surface 28 is square, and the side surfaces 32 to 35 are rectangular, so that the overall shape is a flat box. FIG. 1 is a partially cutaway view of the top surface 26, and shows
Integrated circuit 29 is shown connected to leads 24 by a plurality of thin bonding wires 40 .

Since all leads 24 have the same configuration, it will suffice to consider a particular lead 43. One end of lead 43 is located adjacent to integrated circuit 29 and is connected to the integrated circuit by one bonding wire 40 . The lead 43 passes through the side surface of the enclosure 22 at approximately the center of the distance between the top surface 26 and the bottom surface 28, as shown in FIG. Lead 43 has flat sides 47 (FIGS. 3 and 5).

The corners connecting the sides 32-35 may be of any suitable shape, such as rounded, pointed or chamfered. Side surfaces 32 and 34 constitute a pair of side surfaces;
These sides are parallel and have approximately the same size. The same applies to side surfaces 33 and 35.

The lead 43 extends from one end 45 within the enclosure 22 to the outside of the side surface 34 (see FIG. 3), and further extends along the side surface 34 toward the bottom surface 28 with a flat surface 47. There is. All leads 24 exit the enclosure approximately centrally between the top surface 26 and the bottom surface 28. All leads have a flat surface 47. The bottom surface 28 has a plurality of recesses 5
0 (Figure 2). As shown in FIG. 2, the ends of leads 24 are within recesses 50.

As shown in FIGS. 3 and 4, each lead 24 extends over one of the plurality of ridges 53. As shown in FIGS. These plurality of raised portions 53 are formed by protrusions extending beyond the bottom surface 28 along each side surface 32-35. The raised portion has a slope that is coplanar with the side surfaces 32-35. Each lead passes into one recess 50 over the associated ridge. Accordingly, each recess 50 is provided with a respective associated ridge, and each ridge is associated with one lead.

As shown in Figure 5, one lead 4
3 has a flat surface 47 opposite one associated ridge 58 and extending beyond the ridge 58. Since the ridges 58 are identical in shape to the other ridges 53, it will be sufficient to describe one ridge 58 in detail. The slope 60 of the ridge 58 is coplanar with the side surface 34. The side surface 34 extends from its center to the bottom surface 28.
The section up to the same level can be made into a slope with a small inclination angle (for example, about 3 degrees). The surface of the ridge 58 extends from the ramp 60 through the rounded top 62 and from the rounded top 62 into a corresponding recess 66 . The angle of the second slope 64 with respect to the side surface is approximately 25 degrees. The ramp 64 extends generally away from the side surface 34 toward the bottom surface 28 and toward the opposite side surface 32 (FIG. 2).

In FIG. 5, two positions of lead 43 are shown. The lead 43 is first bent at the rounded top 62, as shown in dotted lines, and then a punch 68 (shown in dotted lines) contacts the portion of the lead beyond this bent portion. Punch 68 deforms the lead and is angularly displaced to a second position adjacent ramp 64 as shown in solid line. In this way, lead 4
3 ends 70 are placed in one recess 66. End 70 is prevented from moving laterally by ribs 73 and 74 (FIG. 2) of ribs 56. The corners 76 of the bottom surface 28 are also raised to obtain ribs, such as ribs 74 in FIG.

Even if a force is applied to pull the lead 43 away from the slope 60 and the side surface 34 of the enclosure 22, the end 70 of the lead 43 and a portion near it will contact the slope 64 to prevent such movement. After the deformation by the punch 68, the lead end 70 contacts the slope 64, so that the flat side surface 47 is not separated from the slope 60 due to its spring back action.

As shown in FIG. 5, the punch 68 moves from a first position shown in dotted lines on the right side to a second position shown in solid lines. This causes the lead 43 to bend along the rounded top 62,
Contacting or proximate to the slope 64. When lead 43 is deformed, even after punch 68 is removed and no longer in contact with lead 43, end 70
remains close to slope 64.

The enclosure 22 has chamfered edges 79 and 8.
0 (Fig. 1), and these edges are
It is useful for aligning the carrier in order to properly connect the leads to, for example, a printed circuit board.

In FIG. 6, two adjacent leads 100 and 102 of leads 24 are shown extending out from enclosure 22. In FIG. Leads 100 and 102 have openings or holes 106 and 108, respectively, near where they exit enclosure 22. The holes shown are rectangular, but may be any suitable shape. This hole increases the flexibility of the lead. Leads 100 and 102 extend downwardly into narrow portions 120 and 122, respectively. Leads 100 and 102 have tapered edges 110, 112 and 114, 116 between narrow portions 120 and 122, respectively. The narrow portions 120 and 122 extend beyond the ridges 130 and 132 into the two recesses 50.
(not shown in FIG. 6).
Leads 100 and 102 can be soldered to printed circuit board 200 at the lower portions 136 and 138 of the top of their respective ridges.

Connect leads 100 and 102 to printed circuit board 2
When soldering to the 00 contact pads 202 and 204, the lower portions 136 and 138 are in contact with the contact pads 202 and 204, and the solder 206 is deposited on the narrow portions 120 and 122 (only a portion of the solder adhered to the lead 102). (Illustrated). The solder is applied to the lower portions of the leads 136 and 1.
38 to connect the leads to printed circuit board 200. Soldering can be performed by reflow, ripping, waving or other suitable methods.

when connected to a printed circuit board or when coming into contact with other objects (e.g. when coming into contact with other carriers during transport) or when being inserted into a socket.
The raised portions 130, 132 serve to hold the leads 100, 102. When the enclosure 22 is inserted into the socket, the leads extending along the sides of the enclosure 22 between the tapered portion 60 and the socket entrance contact the conductors within the socket. Raised portion 13
0,132 also limits the amount of solder that can accumulate between leads 100, 102 and enclosure 22 as a result of wicking effects and prevents bridging of solder 206 between adjacent leads 100 and 102. What is possible is prevented.

Leads 100, 102 through holes 106, 108
is flexible and can compensate for changes in the dimensions of the printed circuit board due to thermal effects. Leads 100 and 102 are separated by region 140. The size of region 140 between lead 100 and lead 102 is approximately equal to the width of lead 100. Lead 102 has approximately the same width as lead 100. The width of the leads is the distance between them,
That is, it may be larger than the size of the area 140. If leads 100 and 102 are not perfectly parallel, the width of the leads may be made slightly less than the spacing between them. Thus, the width of region 140 can be slightly greater than, equal to, or slightly less than the width of lead 100. By spacing the leads by their relative widths, leads from other carriers (not shown) similar to carrier 20 are prevented from interlocking between leads 100 and 102. be done. Such engagement can result in damage to the leads, especially during automated processing steps.

Although the present invention has been described based on drawings,
It goes without saying that modifications other than those mentioned in the above description are possible within the scope of the invention.

[Brief explanation of drawings]

FIG. 1 is a plan view of the integrated circuit carrier of the present invention, with a portion cut away to show internal details (not to scale). Second
The figure is a bottom view, Figure 3 is a side view, Figure 4 is a sectional view taken along line 4--4 in Figure 2, and Figure 5 is a cross-sectional view along line 5 in Figure 2.
6 is a partial view of the carrier showing the sides of two adjacent leads; FIG. (Explanation of symbols), 26...Top surface, 28...Bottom surface,
32-35...Side, 43...Lead, 53...
Ridge, 60...slope.

Claims (1)

[Scope of Claims] 1. An enclosure having a top surface, a bottom surface, and at least one side surface extending from the top surface to the bottom surface, extending from the side surface beyond the bottom surface and mutually extending from the side surface to the bottom surface. a plurality of ridges separated by a gap; and a plurality of leads each having one end located within the enclosure and a portion protruding from the side surface and formed along one of the ridges. , carrier for integrated circuits. 2. An integrated circuit carrier according to claim 1, wherein the enclosure is made of plastic.