JP2580740B2 - Lead frame - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a lead frame of a resin-sealed semiconductor device.

[Conventional technology]

Conventionally, resin-encapsulated semiconductor devices have been used in many types of semiconductor devices because of their excellent mass productivity and low cost. This resin-encapsulated semiconductor device has a semiconductor chip mounted on an island located at the center of a lead frame manufactured by punching a thin metal plate by a press die, and the input / output terminals of the semiconductor chip and the corresponding leads are provided. It has been manufactured by connecting a plurality of leads of a frame with thin metal wires, and then sealing a region including a connection portion between the semiconductor chip and the thin metal wires with a resin.

FIG. 3 is a partial plan view of a lead frame showing a conventional lead frame. As shown in FIG. 1, a semiconductor device of this type includes a lead frame 12 made of a metal plate.
The semiconductor chip 11 having the same shape as the island 2 is mounted on the island 2 located at the center of the semiconductor chip. Next, the input / output terminals (not shown) of the semiconductor chip 11 and the leads 1 are connected to a thin metal wire.
10 and electrically connected. Next, the region of the semiconductor chip 11 including the thin metal wires 10 is sealed with a resin to form a resin body 4 indicated by a two-dot chain line which is an outer body of the semiconductor device. At the time of this resin sealing, the resin flows out of the gap between the upper and lower molds, and the resin accumulates in a space surrounded by the tie bar 3 and the lead 1, thereby forming a resin dam 5 indicated by a two-dot chain line which is a resin flash. Is done.

After the resin sealing, the unnecessary resin dam 5 and the tie bar 3 are punched out of the punched area 7 by a punch having a width slightly smaller than the interval between the leads 1 using, for example, a press die.

[Problems to be solved by the invention]

However, in the conventional lead frame, it is difficult to completely remove the resin dam, which is a resin flash, and often remains attached to the side surface of the lead. Therefore, in the subsequent lead bending step, the resin flash adhering to the lead accidentally falls into the mold, and during the lead bending step, a dent scratch is left on the surface of the lead due to the resin flash. There's a problem. Also, in the above-mentioned tie bar cutting work, the die punch always cuts the resin burrs of this resin dam, and therefore, the blade of the die punch is extremely worn and the life of the die is shortened. There is a problem of doing.

SUMMARY OF THE INVENTION An object of the present invention is to provide a lead frame that maintains the life of a cutting die of a tie bar longer and does not cause dent scratches on the leads due to resin.

[Means for solving the problem]

A lead frame according to the present invention includes an island on which a semiconductor chip is mounted, a plurality of leads that surround the periphery of the island and extend outward and are connected to input / output terminals of the semiconductor chip by thin metal wires. In a lead frame made of a thin metal plate having a tie that is arranged in parallel and intersects the lead and connects the plurality of leads, the tie is adjacent to the periphery of the island at a predetermined interval. The tie bar is provided with a non-circular hole whose one side is adjacent to the connection side end of the tie with the lead and whose side is parallel to the direction in which the leads are arranged.

〔Example〕

 Next, the present invention will be described with reference to the drawings.

FIG. 1 is a partial plan view of a lead frame showing one embodiment according to the present invention. The difference between this lead frame and the conventional lead frame is that the position of the tie bar 3 is formed closer to the island 2. For example, the distance between the side wall of the resin body 4 and the side surface of the tie bar 3 is set to about 0.05 to 0.2 mm. That is, the tie bar 3 is provided at a predetermined size obtained by adding the distance from the periphery of the island 2 to the side wall of the resin body 4 (the thickness of the resin body). This dimension was determined by taking into account the displacement of the sealing position during resin sealing. Another difference is that, for example, rectangular holes 8 are provided on both sides of the tie bar 3. Otherwise, the structure is the same as that of the conventional example.
Since the space surrounded by is small, the occurrence of a resin dam at the time of resin sealing is small, and it hardly occurs in some cases.
Further, when cutting the diver 3, the size of the punch is set to the same size as the punching area 7, that is, from the width of the tie 3,
For example, if the tie bar 3 is cut at a position of the punching area 7 indicated by the two-dot chain line while reducing the size by about 0.1 mm,
The punch can cut the tie bar 3 without covering the resin.

Further, the width of the connecting portions 9a to 9d at the side ends of the hole 8 is narrow, for example, about 0.15 to 0.2 mm.
The tie bar 3 can be easily cut, and the tie bar 3 can sufficiently withstand the sealing pressure of the resin at the time of sealing the resin. Also,
These connecting parts 9a and 9b are up to 0.05 mm when the tie bar 3 is cut.
To some extent, it can be easily removed by, for example, a water jet method.

FIG. 2 is a partial plan view of a lead frame showing another embodiment according to the present invention. In this embodiment, a right triangle hole 8 is formed instead of the rectangular hole formed in the tie bar 3 of the above embodiment. The long sides of the right-angled triangular hole 8 sandwiching the right angles thereof coincide with the extension of the side surface of the lead 1. This embodiment is different from the above-described embodiment in that the tie 3
Since the punch has a large cross-sectional area, there is an advantage that the punch is less likely to be worn.

The present invention is not limited to the shape of the hole described in the above two embodiments, but the point is that the hole is a hole other than a circle, and one side of the hole is a connection end side between the tie bar and the lead. And one side thereof may be parallel to the direction in which the leads are arranged.

〔The invention's effect〕

As described above, according to the present invention, the tie bar of the lead frame is provided closer to the island on which the semiconductor chip is mounted, and the hole is provided in a portion adjacent to the lead of the tie bar. West,
The tie bar can be easily cut without cutting the resin burrs. Therefore, there is an effect that a lead frame that can maintain the life of the cutting die of the tie bar for a longer time and that does not cause dent scratches on the leads due to resin can be obtained.

[Brief description of the drawings]

FIG. 1 is a partial plan view of a lead frame showing one embodiment of the present invention, FIG. 2 is a partial plan view of a lead frame showing another embodiment of the present invention, and FIG. 3 is a lead showing a conventional lead frame. It is a partial top view of a frame. 1 ... Lead, 2 ... Island, 3 ... Taiba, 4 ...
... Resin body, 5 ... Resin dam, 6 ... Lead frame, 7
... Punched area, 8 hole, 9a, 9b, 9c, 9d connecting part, 10 thin metal wire, 11 semiconductor chip.

Claims (1)

(57) [Claims] 1. An island on which a semiconductor chip is mounted, a plurality of leads surrounding the island and extending outward and connected to input / output terminals of the semiconductor chip by thin metal wires, and parallel to the periphery of the island. A lead frame made of a thin metal plate having a tie that is located side by side and intersects the lead and connects the plurality of leads, wherein the tie is provided around the island at a predetermined interval, and the tie is provided. A non-circular hole whose one side is in contact with the end on the connection side with the lead and whose side is parallel to the direction in which the leads are arranged.