JPH0314229B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a resin-sealed semiconductor device, and in particular to a resin-sealed semiconductor device, which is improved in that the number of pins can be increased compared to conventional products, and the heat dissipation performance is not inferior to conventional products. The present invention relates to a resin-sealed semiconductor device having an envelope structure.

[Technical Background of the Invention] When a semiconductor chip that generates a large amount of heat, such as a power IC, is sealed in a resin-sealed envelope, it is necessary to efficiently dissipate the heat generated from the semiconductor chip to the outside of the envelope. Conventionally, the following two types of envelope structures have been adopted.

The first envelope structure is one with a heat sink. For example, as shown in FIG. A semiconductor chip bonded to the other surface of the chip 2 is embedded in the resin molded part 1. In this envelope structure, the lead frame equipped with the lead part 3 has a chip mounting bed part (island). Moreover, the lead frame and the heat sink 2 are separate bodies and are usually made of different materials.

The second envelope structure has fins, and the eighth
As shown in FIG. 9 and FIG.
The fins 6 formed integrally with the resin mold part 7
In this envelope structure, the chip mounting bed portion 5, the fins 6, and the leads 8 are formed on a common lead frame. In addition,
In FIG. 9, 9 is a solder layer bonding the semiconductor chip 4 to the chip mounting bed portion 5, and 10 is a bonding wire.

[Problems in the Background Art] In the case of an envelope structure using the heat sink 2 as shown in FIG. 7, the heat sink 2 is required as an external accessory, and the attachment of the heat sink 2 to the lead frame is difficult. This has to be done by caulking or the like, which poses a problem in that the manufacturing cost per semiconductor device is higher than that of a conventional semiconductor device with a finless envelope structure (not shown).

On the other hand, the semiconductor device having an envelope structure with lead portions 6 as shown in FIGS. 8 and 9 has the following problems.

Fins 6 protruding from the side surface of the resin mold part 7 when the semiconductor device is incorporated into electronic equipment.
must be connected to the cooling section of the electronic device, which requires a large area, and as a result, the packaging density of circuit components including the semiconductor device becomes low, which impedes miniaturization of the electronic device. There is.

Since the wide fins 6 protrude from the side surface of the resin mold part, the structure is such that moisture easily enters into the resin mold part 7 through a small gap created at the joint surface between the fins 6 and the resin mold part. .

In particular, since the root portion of the fin 6 protruding from the side surface of the resin mold part is located on the same horizontal plane continuous with the chip mounting bed part 5, as shown in FIG. If a gap is created in the bonding surface, the path for moisture to enter the chip mounting bed is straight and very short, so that the semiconductor chip 4 is easily attacked by moisture.

Providing wide fins 6 on the outer periphery of the resin molded portion reduces the number of lead portions 8 and therefore requires a reduction in the number of pins (the number of external terminals) of the semiconductor device. Since the degree of integration is higher than before, a larger number of pins is required than before, and therefore, providing the fins 6 hinders the high integration of recent devices. Alternatively, if a lead frame with fins 6 provided in the chip mounting bed portion 5 is used to construct a semiconductor device with the same number of pins as a conventional product without fins, the planar area of the semiconductor device must be increased. If the size of the electronic device increases, the mounting density of circuit components in the electronic device or the like will decrease, and miniaturization of the electronic device or the like will be hindered.

If the fins 6 are provided and the number of pins is the same as in conventional semiconductor devices, the distance between the inner end of each lead portion 8 and the chip mounting bed portion 5 must be increased, and as a result, each lead As the bonding wire connected to the chip becomes longer, problems such as contact between the bonding wire and the chip mounting bed, or mutual contact between the bonding wires may occur, which increases the probability of defective products. increases significantly.

As described above, conventional resin-sealed semiconductor devices have had various problems.

[Object of the Invention] An object of the present invention is to provide an improved resin-sealed semiconductor device that does not have the above-mentioned problems. Specifically, the object is to provide a semiconductor device with a small external dimension without fins protruding from the outer periphery of a resin molded part, and also to provide a semiconductor device with a large number of pins despite the small external dimension. Furthermore, it is an object of the present invention to provide a resin-sealed semiconductor device that has good heat dissipation properties and moisture resistance, is free from the possibility of producing defective products due to bonding wires, and can be manufactured at low cost. It is.

[Summary of the Invention] The resin-sealed semiconductor device according to the present invention is characterized in that the tie bar protruding from the outer periphery of the chip mounting bed is provided with at least one U-shaped bent portion, and the bottom surface of the U-shaped bent portion is provided with at least one U-shaped bent portion. This is because it is exposed on the surface of the resin mold part. According to this structure, the tie bars act as heat sinks, so there is no need to provide fins like in conventional products, and the number of pins (leads) can be increased. At the same time, heat can be dissipated without using a heat sink. A resin-sealed semiconductor device with good properties can be manufactured at low cost. Furthermore, in the semiconductor device of the present invention having the above-described structure, each lead part can be placed near the chip mounting bed part, so there is no need to increase the length of the bonding wire. The probability of occurrence is low and it can be manufactured with high yield. Furthermore, since the number of pins is large, highly integrated ICs and the like can be manufactured.

[Embodiment of the Invention] An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

FIG. 1 is a perspective view showing the state of the DIP resin-sealed semiconductor device according to the present invention before resin sealing. 11 is a lead portion which also constitutes a part of the lead frame; 11 is a tie bar which is also a part of the lead frame and protrudes from the outer periphery of the chip mounting bed portion 5; and 9 is a tie bar for mounting the semiconductor chip 4. Bed part 5
10 is a solder layer adhered to a semiconductor chip 4.
This is a bonding wire connected to the upper bonding pad and lead portion 8.

Most of the tie bar 11 is formed wider than each lead part 8, and a narrow part 11b is provided at the tip thereof. Further, a substantially U-shaped bent part 11a is formed in the wide part, and the horizontal part of the bent part 11a, that is, the bottom part of the U-shape, is formed with the resin when the resin molded part 7 is formed as shown in FIG. Since the tie bars 11 are exposed on the bottom surface of the mold part 7 (the surface opposite to the surface on which the semiconductor chip is mounted), they function as a heat dissipation plate, and therefore the resin-sealed semiconductor device has good heat dissipation properties like the conventional finned semiconductor device. It is becoming. Furthermore, although the bent portion 11a of the tie bar 11 is exposed on the surface of the resin molded portion 7, the exposed portion is not in a place where a gap is likely to be created between the resin molded portion and the resin molded portion from the surface. Since moisture must take a curved path to enter into the semiconductor device 7, there is little risk that the moisture will reach the chip mounting bed, making the semiconductor device highly moisture resistant from this point of view as well.

Furthermore, since the semiconductor device of the present invention does not have fins as in conventional fin-equipped semiconductor devices, the number of pins is greater than that of the conventional fin-equipped semiconductor device, and the structure is suitable for multi-pin high-density ICs. There is.

FIG. 3 is a bottom view of a semiconductor device according to a second embodiment of the present invention. The semiconductor device shown in this embodiment is constructed using a flat package lead frame. A tie bar 11 having the same shape as that shown in FIG. ing. In addition, with the lead frame having the above structure, the lead parts can be arranged closely over the entire length of the outer periphery of the chip mounting bed regardless of the existence of the exposed tie bar parts (the lead parts and the exposed tie bar parts are In the semiconductor device shown in FIG. 3, the lead parts 8 are densely planted over the entire outer periphery of the resin mold part 7, and the four tie bars
The bent portions 11a are exposed at the bottom surface of the resin molded portion 7.

4 and 5 are cross-sectional views showing an embodiment of the present invention, and FIG. 4 shows the bent portion 11a of the tie bar 11.
FIG. 5 shows an embodiment in which the bent portion 11 of the tie bar 11
An example of a structure in which part a is exposed on the lower surface of the resin molded part 7 is shown. Further, FIG. 5 shows an embodiment in which a plurality of bent portions 11a are formed on the tie bar 11 and one of the bent portions is made to protrude from the lower surface of the resin molded portion 7. Note that in this figure, parts indicated by the same reference numerals as in FIG. 1 represent the same parts as shown in FIG. 1.

6a, b, and c show examples of the planar shape of the tie bar bent portions 11a exposed on the surface of the resin molded portion 7, and the shape of the tie bar bent portions exposed on the surface of the resin molded portion 7 is as follows. As shown in FIG. 6, various shapes may be used.

[Effects of the Invention] As explained in the above embodiments, the semiconductor device of the present invention has the following advantages: (a) Since the fins do not protrude from the side surface of the resin molded part, the semiconductor device is small and occupies a small area; It can be mounted in electronic equipment, etc. with a higher packing density than semiconductor devices, and is advantageous for miniaturizing electronic equipment. (b) It has better moisture resistance than semiconductor devices with fins, and is as good as the semiconductor devices. (c) Has more pins than semiconductor devices with fins,
The semiconductor device of the present invention has various advantages such as being suitable for high-density ICs, and (d) being able to be manufactured at a much lower cost than semiconductor devices with heat sinks. And problems related to semiconductor devices with heat sinks are solved.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a resin-sealed semiconductor device of the present invention in a state before resin sealing, FIG. 2 is a bottom view of the semiconductor device of FIG. 1 in a completed state, and FIG. Bottom view of a semiconductor device of another embodiment, No. 4
5 and 5 are cross-sectional views of modified embodiments of the semiconductor device shown in FIGS. 1 and 2, and FIG. 6 shows bent tie bars exposed on the surface of the resin molded portion in each of the embodiments shown in FIGS. 1 to 5. 7 is a perspective view of a known resin-sealed semiconductor device with a heat sink, FIG. 8 is a perspective view of a known resin-sealed semiconductor device with fins, and FIG. 9 is a perspective view of a known resin-sealed semiconductor device with fins. It is a sectional view taken along the - arrow in the figure. 1... Resin mold part, 2... Heat sink (heat sink), 3... Lead part, 4... Semiconductor chip,
5... Chip mounting bed part, 6... Fin, 7...
...Resin mold part, 8... Lead part, 9... Solder layer, 10... Bonding wire, 11... Tie bar, 11a... Tie bar bent part, 11b...
Narrow part (of a tie bar).

Claims (1)

[Claims] 1. Using a lead frame having a chip mounting bed section for mounting a semiconductor chip, a tie bar protruding from the outer periphery of the chip mounting bed section, and a lead section disposed around the chip mounting bed section, In a resin-sealed semiconductor device in which the entire mounting bed portion, substantially the entire tie bar, and one end side of the lead portion are encapsulated within a resin mold portion, the tie bar has at least one U-shaped bent portion. 1. A resin-sealed semiconductor device characterized in that a bottom portion of the U-shaped bent portion is exposed on a surface of the resin mold portion.