JPH0756890B2 - Method for manufacturing semiconductor device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for manufacturing a semiconductor device provided with a heat dissipation plate, and in particular to an improvement in a connection method between the lead frame and a heat dissipation plate when both are used. It is about.

(Prior Art) Conventionally, in a manufacturing process of a semiconductor device having a heat sink, an island is formed at the tip of an elongated suspension pin 3 extending from a connecting portion 2 of a lead frame 1 as shown in FIG. The radiating plate 4 which also serves as a caulking connection. The hanging pins 3 are cut together with the outer leads 5 in the cutting process of the outer leads 5 performed after the circuit chip C is mounted on the heat dissipation plate 4 and the resin sealing is performed.

However, in the case of this method, the lead frame 1
As the number of pins increases and the hanging pins 3 become thinner, caulking connection between the hanging pins 3 and the heat sink 4 becomes difficult.

(Problems to be Solved by the Invention) Therefore, the present invention is a method of connecting a heat sink to a lead frame in the manufacturing process thereof, and the heat sink can be easily attached to the lead frame regardless of the increase in the number of pins of the lead frame. It is an object to provide a method that can be connected.

(Means for Solving the Problems) In order to solve the above problems, in the present invention, the heat dissipation plate frame that supports the heat dissipation plate 24 separately from the lead frame 11 is provided.
21 is formed, and the lead frame 11 and the heat radiating plate frame 21 are caulked at an appropriate portion. The radiator plate frame 21 includes a thick radiator plate 24 located at the center and the radiator plate 24.
Connection part that surrounds the four sides of the heat dissipation plate 24 with a space between it and
The structure has 22 and a hanging pin 23 that connects the connecting portion 22 and the four pairs of the heat dissipation plate 24. Then, the heat dissipation plate frame 21 is formed by punching out the modified cross-section strip plate 31 having the thin parts 33 on both sides of the thick part 32 which constitutes the heat dissipation plate 24. The lead frame 11 and the heat sink frame 21 are connected as follows. That is, by disposing the heat dissipation plate 24 at a predetermined position in the center of the lead frame 11,
And the heat dissipation frame 21 are overlapped with each other, like the connecting portion 22,
The caulking is performed at a portion having a sufficient caulking area other than the hanging pin 23. Then, after mounting the circuit chip C and performing wire bonding, the hanging pins 23 are cut together with the leads 15 to separate the heat sink 24 from the heat sink frame 21.

(Operation) In the present invention, the heat dissipation plate frame 21 is caulked to the lead frame 11 at a portion having a relatively large area such as the connecting portions 12 and 22. Therefore, a sufficiently large area can be secured for caulking connection. Even if the lead frame 11 has multiple pins, the lead frame 11 and the heat sink frame 21
There is no influence on the area of the connecting portions 12 and 22 of. If the profile section strip plate 31 has a thick portion with a thickness as large as possible and a thin portion with a thickness as small as possible, a large radiator plate 24 with good heat dissipation efficiency can be obtained. Nevertheless, since the hanging pin 23 is thin, the cutting operation is easy.

(Embodiment) An embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a plan view of the lead frame and heat sink frame in a superposed state, Fig. 2 is a sectional view taken along the line II-II of Fig. 1, Fig. 3 is a sectional view taken along the line III-III of Fig. 1, and Fig. 4 is a sectional view of the lead frame. Plan view, FIG. 5 is a plan view of the heat sink frame, FIG. 6 is a sectional view taken along line VI-VI of FIG. 5, and FIG.
Figure is a plan view of the modified cross-section strip. Figure 8 is Figure 7 VIII-VIII.
FIG. 9 is a sectional view taken along the line IX-IX in FIG.

In the illustrated embodiment, a lead frame 11 having a large number of leads 15 and a heat radiating plate frame 21 having a heat radiating plate 24 are separately formed, and these are polymerized as shown in FIGS. 1 to 3, The boss portions 25 lateral to each other are caulked.

As shown in FIG. 4, many lead frames 11 are continuously formed on a long strip plate. The lead frame 11 is formed by extending a large number of leads 15 from the four surrounding connecting portions 12 toward the center, and the center portion surrounded by the tips of the leads 15 is provided with a space portion 16 for disposing a heat sink, Holes 17 into which the caulking boss portions 25 of the heat dissipation plate frame 21 are fitted are provided on both sides.

As shown in FIGS. 5 to 7, the radiator plate frame 21
Is a connecting portion 22 that surrounds the four surroundings of the heat dissipation plate 24 with a space between the thick heat dissipation plate 24 located in the center and the heat dissipation plate 24.
And a suspension pin 23 that connects the connecting portion 22 and the four pairs of the heat radiating plate 24, and boss portions 25 that fit into the holes 17 of the lead frame 11 are provided on both sides. Thus, the heat dissipation plate frame 21 has a long strip-shaped cross-section strip shown in FIGS. 8 and 9.
A large number are continuously formed on 31. This irregular section strip 31
On both sides of the thick part 32 that should constitute the heat sink 24,
It has a thin portion 33 that should constitute 23, and the thick portion 32 and the thin portion 33 extend in the longitudinal direction. The heat dissipation plate frame 21 is formed by punching out the strip 31 having the irregular cross section.

The lead frame 11 and the heat sink frame 21 are connected as follows. That is, as shown in FIGS. 1 to 3, by disposing the heat dissipation plate 24 at a predetermined position in the space 16 in the central portion of the lead frame 11, the lead frame 11 and the heat dissipation frame are disposed.
21 is overlapped, the hole 17 in the connecting portions 12 and 22 and the boss portion 25 are fitted to each other, the boss portion 25 is compressed, and both are caulked. Then, after mounting the circuit chip C and performing wire bonding, the hanging pins 23 are cut together with the leads 15 to separate the heat sink 24 from the heat sink frame 21.

In this embodiment, the heat dissipation plate frame 21 is caulked at the hole 17 and the boss portion 25 on the connecting portions 12 and 22. Since this area has a relatively large area, the space required for caulking can be easily secured. Therefore, a sufficiently large area can be secured for caulking connection. Even if the lead frame 11 has a large number of pins, the area of the connecting portions 12 and 22 of the lead frame 11 and the heat dissipation plate frame 21 is not affected at all. Further, if a thick section 32 of the deformed cross-section strip plate 31 having a large thickness is adopted, a large heat dissipation plate 24 having good heat dissipation efficiency can be obtained. Also in this case, since the hanging pin 23 is thin, it does not hinder the cutting work.

Although the lead frame 11 and the heat dissipation plate frame 21 are caulked in the above embodiment, the connection method is not limited to this. For example, a method of connecting both connecting portions 12 and 22 with an adhesive may be considered.

As described above, in the present invention, the heat dissipation plate frame 21 that supports the heat dissipation plate 24 is formed separately from the lead frame 11,
The lead frame 11 and the heat dissipation plate frame 21 are connected to each other by an appropriate method such as caulking connection or connection with an adhesive at an appropriate portion. The radiator plate frame 21 has a space between the thick radiator plate 24 located at the center and the radiator plate 24,
A structure is provided that includes a connecting portion 22 that surrounds the four sides of the heat dissipation plate 24, and a hanging pin 23 that connects the connecting portion 22 and the four pairs of the heat dissipation plate 24. Then, the heat dissipation plate frame 21 is formed by punching out the modified cross-section strip plate 31 having the thin parts 33 on both sides of the thick part 32 which constitutes the heat dissipation plate 24. Lead frame 11
The heat sink frame 21 is connected to the heat sink frame 21 as follows. That is, the heat dissipation plate 24 is arranged at a predetermined position in the central portion of the lead frame 11, the lead frame 11 and the heat dissipation plate frame 21 are overlapped, and the two are sufficiently connected to each other, such as the connecting portions 12 and 22, except the hanging pin 23 portion. Connection is made at a portion having a large connection area. Then, after mounting the circuit chip C and performing wire bonding, the hanging pins 23 are cut together with the leads 15 to separate the heat sink 24 from the heat sink frame 21. Therefore, there is an effect that the heat sink 24 can be easily connected to the lead frame 11 regardless of the increase in the number of pins of the lead frame 11.

[Brief description of drawings]

1 to 7 show an embodiment of the present invention.
FIG. 1 is a plan view of a lead frame and a heat sink frame in a superposed state, FIG. 2 is a sectional view taken along line II-II of FIG. 1, and FIG.
II-III sectional view, FIG. 4 is a plan view of the lead frame, FIG.
Fig. 6 is a plan view of the heat sink frame, Fig. 6 is a cross-sectional view taken along line VI-VI of Fig. 5, Fig. 7 is a plan view of a modified cross-section strip plate, and Fig. 8 is Fig. 7.
VIII-VIII sectional view, FIG. 9 is FIG. 7 IX-IX sectional view,
FIG. 10 is a schematic cross-sectional view showing a conventional heat dissipation plate connection structure. 11 …… Lead frame, 12 …… Coupling part, 15 …… Lead,
21 ...... Heat sink frame, 22 ...... Connection part, 23 ...... Suspension pin, 24 ...... Heat sink, 31 ...... Strip section with irregular shape, 32 ...... Thick part, 33 ...... Thin part.

Claims (3)

[Claims] 1. A separate heat sink for an island is connected to the central portion of a lead frame in which a large number of leads are extended from the four connecting portions toward the center, and a circuit chip is mounted on the island. In a method including a step of separating the lead frame and the heat dissipation plate after performing wire bonding between the circuit chip and the lead, a variant having thin parts on both sides of a thick part that constitutes the heat dissipation plate. By punching out the cross-section strip plate, a thick heat dissipation plate located in the center, a connecting portion surrounding the four surroundings of the heat dissipation plate with a space between the heat dissipation plate, and the four joints of the connection part and the heat dissipation plate. Forming a heat dissipation plate frame having a hanging pin for connecting the heat dissipation plate and the heat dissipation plate at a predetermined position in the center of the lead frame, stacking the lead frame and the heat dissipation frame, and suspending both of them. The method of manufacturing a semiconductor device which is connected at a site having a sufficient connection area other than the emission portion, by cutting the pin hanging after wire bonding, characterized in that disconnecting the radiator plate from the heat radiating plate frame. 2. A separate heat sink also serving as an island is connected to the center of a lead frame in which a large number of leads are extended from the connecting portion of the four enclosures toward the center, and a circuit chip is mounted on the island. In a method including a step of separating the lead frame and the heat dissipation plate after performing wire bonding between the circuit chip and the lead, a variant having thin parts on both sides of a thick part that constitutes the heat dissipation plate. By punching out the cross-section strip plate, a thick heat dissipation plate located in the center, a connecting portion surrounding the four surroundings of the heat dissipation plate with a space between the heat dissipation plate, and the four joints of the connection part and the heat dissipation plate. Forming a heat dissipation plate frame having a hanging pin for connecting the heat dissipation plate and the heat dissipation plate at a predetermined position in the center of the lead frame, stacking the lead frame and the heat dissipation frame, and suspending both of them. The method of manufacturing a semiconductor device by caulking connection at the site with sufficient crimping area other than the emission portion, by cutting the pin hanging after wire bonding, characterized in that disconnecting the radiator plate from the heat radiating plate frame. 3. A separate heat sink also serving as an island is connected to the center of a lead frame in which a large number of leads are extended from the connecting portion of the four enclosures toward the center, and a circuit chip is mounted on this island. In a method including a step of separating the lead frame and the heat dissipation plate after performing wire bonding between the circuit chip and the lead, a variant having thin parts on both sides of a thick part that constitutes the heat dissipation plate. By punching out the cross-section strip plate, a thick heat dissipation plate located in the center, a connecting portion surrounding the four surroundings of the heat dissipation plate with a space between the heat dissipation plate, and the four joints of the connection part and the heat dissipation plate. Forming a heat dissipation plate frame having a hanging pin for connecting the heat dissipation plate and the heat dissipation plate at a predetermined position in the center of the lead frame, stacking the lead frame and the heat dissipation frame, and suspending both of them. The method of manufacturing a semiconductor device connected with an adhesive at the site with sufficient adhesion area other than the emission portion, by cutting the pin hanging after wire bonding, characterized in that disconnecting the radiator plate from the heat radiating plate frame.