JP3008973U - Lead frame with heat sink - Google Patents

Abstract

(57) [Summary] [Structure] A lead frame with a radiator plate having a radiator plate fixing frame provided on the side of the inner lead and a radiator plate integrally formed at the tip opposite to the outer lead of the radiator plate fixing frame. In addition, the heat radiation plate is bent and overlapped with the boundary line between the heat radiation plate fixing frame and the heat radiation plate as a fold, and the heat radiation plate fixing frame and the heat radiation plate are brought into close contact with each other. [Effect] The transfer press line can be manufactured at once, the dimensional accuracy and the mutual positional accuracy can be kept high, the defect rate can be reduced, and the management, transportation and setting of each component are not required.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a lead frame with a heat sink (or heat sink) for power transistors and the like.

[0002]

[Prior art]

 First, the heat sink 1 or the heat sink whose side is shown in FIG. 4 and the lead frame 2 whose side is shown in FIG. 5 are manufactured as separate parts in different steps. Here, the pin 101 is integrally formed at a predetermined position of the heat dissipation plate 1, and a through hole 201 for fitting with the pin 101 is provided at a corresponding predetermined position of the lead frame 2. ing. Next, the heat radiating plate 1 and the lead frame 2 are combined as shown in FIG. 6, and the tips of the pins protruding from the through holes 201 are struck and crushed to be caulked.

[0003]

[Problems to be solved by the device]

 Since this is a method of combining the heat sink 1 and the lead frame 2 and fitting the pins 101 and the through holes 201, the dimensional accuracy and position accuracy of the individual parts are more severe, and each part is transferred to the assembly line. There is a problem that it must be carried and set accurately.

Therefore, an object of the present invention is to solve the above problems and provide a lead frame with a heat sink, which has a high manufacturing yield.

[0005]

[Means for Solving the Problems]

 The above-mentioned object is the present invention according to claim 1, that is, the heat radiation plate fixing frame provided on the side of the inner lead and the outer lead of the heat radiation plate fixing frame are integrally formed at the tip on the opposite side. A heat dissipation plate lead frame having a plate, wherein the heat dissipation plate fixing frame and the heat dissipation plate are bent and overlapped with each other with the boundary line between the heat dissipation plate fixing frame and the heat dissipation plate as a fold, and the heat dissipation plate fixing frame and the heat dissipation plate are closely attached This is achieved by a lead frame with a heat radiating plate. Here, the inner lead means a lead on the semiconductor chip fixing portion side of the tie bar, and the outer lead means a lead on the opposite side of the tie bar.

In a preferred embodiment of the present invention, as described in claim 2, a V-shaped groove or an R-shaped groove is formed in a fold which becomes an inside or an outside when being bent.

[0007]

【Example】

 Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

In the first-stage manufacturing process, a long metal strip having a different shape, in which the plate thickness is thick only from a predetermined width to both edges, in particular, a copper strip or a copper alloy strip for a lead frame is press-punched and The shape is as shown in. The lead frame 4 in which the outer lead 401, the tie bar 402, and the inner lead 403 are arranged in this order from the left, the two radiator plate fixing frames 3 provided on both sides of the inner lead, and the tip of the radiator plate fixing frame. The heat sink 5 is formed. The heat sink 5 is thicker than the lead frame 4 and the heat sink fixing frame 3. Further, the heat dissipation plate 5 is connected to the heat dissipation plate fixing frame 3 at two positions, that is, the upper end and the lower end of the side. A boundary line between the heat sink 5 and the heat sink fixing frame 3 is a linear fold line 501, and a V-shaped groove 502 is provided on the back surface in FIG. In the first step, the V-shaped groove is formed by pushing in the blade at the same time as punching. Each of the heat radiation plate fixing frames 3 is provided with two circular through holes 301 at predetermined positions. Correspondingly, two pins 503 are formed on the back surface of the heat dissipation plate 5 in FIG. 2 near the upper side and near the lower side. The formation of the pin 503 is also performed simultaneously by compressing the female mold in the first step.

In the second manufacturing process that follows the first manufacturing process, the base 302 of the heat dissipation plate fixing frame 3 near the tie bar is lightly bent to form the heat dissipation plate fixing frame as shown in FIG. The surface of 3 is parallel to the surface of the inner lead 403, and is precisely processed so that it is lowered by a certain distance.

In the subsequent third manufacturing process, the heat radiating plate 5 is bent downward with the fold line 501 as the central axis, and further bent by 180 ° to bring them into close contact with each other as shown in FIG. At that time, the pin 503 provided on the heat sink 5 is inserted into the through hole 301 of the heat sink fixing frame 3, and the tip of the pin 503 projects from the through hole 301. Then, while supporting the heat sink 5 from below, the tip of the pin 503 is struck from above to be crushed and caulked. Then, the heat dissipation plate 5 is fixed in close contact with the heat dissipation plate fixing frame 3.

The lead frame with a heat radiating plate of the present invention is a transfer press in which a large number of punching dies, bending dies, etc. are continuously arranged in a line, and differently shaped metal strips are processed by intermittently feeding them. It can be manufactured all at once on the line. As a result, the pin dimensional accuracy and position accuracy and the through hole dimensional accuracy and position accuracy tend to have the same deviation due to simultaneous processing. Can be lowered. In addition, since the raw material is only metal strips, management becomes comparatively easy.

A semiconductor product such as a power transistor is manufactured from the lead frame with a heat sink of the present invention as follows. A plate-like semiconductor chip is bonded and fixed to the center of the heat sink from above. The heat dissipation plate fixing frame and the heat dissipation plate are previously bent so that the surface of the semiconductor chip and the upper surface of the inner lead are located on the same plane so that the heat dissipation plate is lower than the inner lead. Then, wire bonding is performed between the electrode of the semiconductor chip and the upper surface near the tip of the inner lead. Next, the semiconductor chip and wires are encapsulated, and then the tie bar is partially cut off to obtain a semiconductor product.

[0013]

[Effect of device]

 The present invention integrally connects a lead, a heat sink fixing frame and a heat sink, and bends them by 180 ° with a boundary line between the heat sink fixing frame and the heat sink as a fold line to combine the heat sink and the heat sink fixing frame. Since it is fixed, (1) it can be manufactured all at once on the transfer press line, (2) dimensional accuracy and mutual position accuracy are kept high, so the defect rate can be greatly reduced, and (3) each The remarkable effect is that parts management, transportation and setting are not required.

[Brief description of drawings]

FIG. 1 is a side view of a lead frame with a heat sink according to an embodiment of the present invention.

FIG. 2 is a plan view of a lead frame with a heat sink according to an embodiment of the present invention in a first stage manufacturing process.

FIG. 3 is a plan view of a lead frame with a heat sink according to an embodiment of the present invention in a second manufacturing process.

FIG. 4 is a side view of a conventional heat sink.

FIG. 5 is a side view of a conventional lead frame.

FIG. 6 is a side view of a conventional lead frame with a heat sink.

[Explanation of symbols]

 1 heat sink 101 pin 2 lead frame 201 through hole 3 heat sink fixing frame 301 through hole 302 root 4 lead frame 401 outer lead 402 tie bar 403 inner lead 5 heat sink 501 fold 502 V-shaped groove 503 pin

Claims (2)

[Scope of utility model registration request] 1. A lead frame with a heat radiating plate having a heat radiating plate fixing frame provided on a side of the inner lead and a heat radiating plate integrally formed at a tip opposite to the outer lead of the heat radiating plate fixing frame. A lead frame with a heat radiating plate, characterized in that the heat radiating plate is bent and overlapped with a boundary line between the heat radiating plate fixing frame and the heat radiating plate as a fold, and the heat radiating plate fixing frame and the heat radiating plate are brought into close contact with each other. 2. The lead frame with a heat radiating plate according to claim 1, wherein a V-shaped groove or an R groove is formed in a fold which is an inside or an outside when being bent.