JPH06163778A - Semiconductor device and its manufacture - Google Patents

Abstract

PURPOSE:To enhance the flatness of inner leads by a method wherein a heat treatment process used to remove a residual stress in a working history stored in a lead frame is omitted, the manufacturing process of the lead frame is shortened, the deformation of the inner leads is prevented, the positional accuracy of the inner leads is enhanced and the levitation and fall of the inner leads is eliminated. CONSTITUTION:The title semiconductor device is provided with many leads 12, with a frame-shaped bonding part 14 which connects inner leads 13 collectively and which is composed of an insulating adhesive material and with a heat sink 16 provided with a semiconductor-element mounting part formed in such a way that an outer edge part 16a in which cutout holes 17 have been made at least in individual corner parts has been bent to be a stepped shape by forming a frame-shaped flat part 16b thermocompression-bonded to the bonding part 14 at the outside. In addition, the title semiconductor device is provided with a semiconductor element 15 mounted on the semiconductor-element mounting part, with wires connecting the inner leads 13 to electrodes for the semiconductor element 15 and with a molding body 20 which resin-molds the semiconductor element 15 and its mounting part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device and a method of manufacturing the same, and more specifically, it diffuses heat generated by a semiconductor element and prevents deformation of the inner lead when residual stress accumulated in the inner lead is released. The present invention relates to a semiconductor device in which a heat sink is separately mounted on a lead frame, and a manufacturing method thereof.

[0002]

2. Description of the Related Art In recent years, as a measure against heat generation of a semiconductor element due to high integration of a semiconductor device, a heat sink (radiating plate) for diffusing the heat is attached to the semiconductor device or the semiconductor device has a large number of pins. The heat treatment for removing the residual stress of the leads is performed. Hereinafter, a conventional semiconductor device will be specifically described with reference to FIGS.

A conventional semiconductor device 100 has a laminated lead frame L as shown in FIG. In this laminated lead frame L, a strip material is pressed or etched to provide a lead frame main body 102 having a large number of leads 101 and the like, and then a heat treatment for removing residual stress caused by the processing history is performed. , The surface is plated. Subsequently, the inner leads 103 are collectively connected to the back surface of the tip end portion of the inner lead 103 of the lead 101, and a frame-shaped insulating tape 104 made of a thermoplastic insulating adhesive is adhered to this frame-shaped insulation. Tape 1
The semiconductor element 10 is connected to the inner lead 103 via 04.
The laminated lead frame L is manufactured by connecting the heat sink 106 that also serves as the mounting portion of No. 5. Bent support leads 107 are provided at the four corners of the heat sink 106 so as to project from each support lead 107.
Are thermocompression bonded to corresponding corners of the frame-shaped insulating tape 104. The inner leads 103 are not arranged at the corners of the frame-shaped insulating tape 104.

Although not shown in the drawings, as another conventional lead frame, the heat sink is provided in a space in front of the inner lead via four long support leads extending downward from the lead frame body in a bent state. It is known that the pendant is suspended in the air. The heat sink 10 used for the conventional laminated lead frame L
As shown in FIG. 11, the support lead 107 of No. 6 is bent so that the upper portion thickness A and the lower portion thickness B of the molded body 109 are substantially the same. In this laminated lead frame L, the semiconductor element 105 is mounted on the upper surface of the bottom of the heat sink 106 which also serves as the semiconductor element mounting portion, and then the inner lead 103 and the electrodes of the semiconductor element 105 are connected by the wire 108, and then the semiconductor element 105. Then, the mounting portion thereof is resin-molded to provide the molded body 109, and then the tip of the outer lead 110 is cut and the forming is performed to manufacture the semiconductor device 100.

[0005]

However, in the conventional laminated lead frame L, the inner leads 103 are not arranged at the respective corners of the group of inner leads 103 to which the support leads 107 are thermocompression bonded as described above. The support lead 103 is thermocompression bonded only to the frame-shaped insulating tape 104. Therefore, when the inner lead 103 is heated in a subsequent process such as an assembling process, the residual stress of the processing history that has been removed in advance is released and the tip portion of the inner lead 103 is deformed, which makes the wire bonding unstable. . Therefore, there is a problem in that after the shape processing of the laminated lead frame L, a heat treatment for removing the residual stress is required again, and equipment and working steps for this heat treatment are required. Furthermore, recently, the semiconductor device 10
With the high integration of 0, the semiconductor element 105 becomes large,
The distance between the tip of the inner lead 103 and the end of the mold body 109 is shortened, and when the outer lead 110 is formed, the inner lead 103 is pulled outward, which causes stress on the wire 108, and the molding resin. However, there is a problem in that the adhesiveness of the product deteriorates and the long-term reliability decreases.

The present invention has been made in view of the above circumstances, and the heat treatment step for removing the residual stress in the working history accumulated in the lead frame is omitted to shorten the manufacturing process and to improve the heat dissipation efficiency. To provide a semiconductor device and a method for manufacturing the same in which the inner lead is prevented from being deformed, the inner lead is improved in positional accuracy, and the inner lead is prevented from rising or falling to improve the flatness of the inner lead. With the goal.

[0007]

A method according to the above-mentioned object.
The semiconductor device described above includes a large number of leads, a frame-shaped joint made of an insulating adhesive material that collectively connects the inner leads of the leads, and an outer edge portion provided with a cutout hole at least at each corner. A heat sink having a semiconductor element mounting portion in which a frame-shaped flat portion that is thermocompression bonded to the joint portion is provided outside and bent in a step shape; and a semiconductor element mounted on the semiconductor element mounting portion of the heat sink, A wire is provided for connecting the electrode of the semiconductor element and the inner lead, and a mold body for resin-molding the semiconductor element and its mounting portion is provided. According to a second aspect of the present invention, there is provided a semiconductor device manufacturing method, wherein a lead frame strip is punched out to provide an intermediate lead frame body in which the tips of inner leads of a large number of leads are connected by a connecting portion.
An insulating tape made of an insulating adhesive is adhered to at least one surface of the tip portion and the connecting portion of the inner lead, and then the connecting portion is punched to cut the tip of each inner lead, and at the same time, the inner lead is collectively attached. A frame-shaped joint portion made of the insulating tape to be connected to each other is provided, and an outer edge portion of the heat sink having the semiconductor element mounting portion is provided with cutout holes at least at each corner, and a frame-shaped flat portion is provided outside. Provided and bent in a step shape, then through the joining portion, the flat portion of the heat sink is joined to the inner lead of the lead frame body, and then the semiconductor element is mounted on the semiconductor element mounting portion of the heat sink. An electrode of the semiconductor element and the inner lead are connected by a wire, and then the semiconductor element and the semiconductor element mounting part are molded. It is more resin molded configuration.

[0008]

In the semiconductor device and the method of manufacturing the same according to claims 1 and 2, pressure is applied from the outside so that the outer edge portion of the heat sink supporting the semiconductor element mounting portion is bent in a stepped manner. When forming, since the notch holes are provided at least at each corner of the outer edge portion, the support lead portion between the notch holes of the outer edge portion has a frame-shaped flat portion with almost no distortion outside the outer edge portion. The semiconductor element mounting portion can be bent, leaving the above. Then, the flat portion is thermocompression-bonded to the frame-shaped joint portion of the inner lead, so that the heatsink is formed by thermocompression-bonding the support leads extending from the four corners of the semiconductor element mounting portion as in the conventional case, and the lead frame main body. As compared with the integrated long support lead, thermocompression bonding is applied to the tip portions of all the inner leads, so that mounting and supporting of the semiconductor element mounting portion are stabilized.

Moreover, since the inner lead is firmly thermocompression-bonded to the frame-shaped flat portion via the joining portion in this manner, the semiconductor device of the semiconductor device can be manufactured without heat treatment for removing residual stress accumulated in the lead. It is possible to prevent deformation of the inner leads due to release of residual stress generated during heating in a post process such as assembly, and prevent the leads from leaning or rising or falling. Further, since the inner lead is fixed by the frame-shaped flat portion, it is possible to prevent the inner lead from being pulled when forming the outer lead, and improve the adhesion of the molding resin.

[0010]

Embodiments of the present invention will now be described with reference to the accompanying drawings to provide an understanding of the present invention. 1 is an enlarged perspective view of a semiconductor device according to an embodiment of the present invention and a semiconductor device according to a manufacturing method thereof, FIG. 2 is an exploded perspective view of the same lead frame, FIG. 3 is a sectional view thereof, and FIG.
4 (a) is a perspective view of the lead frame body punched and punched, and FIG. 4 (b) is a perspective view showing a state in which a tip portion of the inner lead and a connecting portion connecting the tips are attached with an insulating tape. FIG. 5C is a perspective view in which a connecting portion that connects the tips of the inner leads is removed, FIG. 5A is a perspective view during punching of a required shape of the heat sink, and FIG. 5B is bending processing of the heat sink. 5C is a cross-sectional view of the heat sink during punching, FIG. 6A is a perspective view of the heat sink mounted on the lead frame body, and FIG. 6B is the lead frame. FIG. 7A is a cross-sectional view of the heat sink bonded to the main body during thermocompression bonding, FIG. 7A is a cross-sectional view of the inverted lead frame, and FIG. 7B is a cross-sectional view of the heat sink in which a bond is applied on the semiconductor element mounting portion. , Fig. 8
8A is a sectional view of the heat sink during mounting of the semiconductor element on the semiconductor element mounting portion, and FIG. 8B is a sectional view after wire connection between the inner lead and the electrode of the semiconductor element.
9C is a cross-sectional view of the mounting portion of the semiconductor element after resin molding, FIG. 9A is a cross-sectional view after cutting the tip of the inner lead, and FIG. 9B is a cross-section of the outer lead during forming. The figure is shown.

First, the structure of a semiconductor device according to an embodiment of the present invention will be described. A semiconductor device 10 according to an embodiment of the present invention shown in FIG. 1 is provided with the laminated lead frame L shown in FIGS. The laminated lead frame L has a lead frame body 11 punched by a progressive die. The lead frame main body 11 is provided with a large number of leads 12, and the tips of the inner leads 13 of the respective leads 12 are frame-shaped as an example of a frame-shaped joint made of a thermoplastic insulating adhesive material. They are connected together by the insulating tape 14. On the lower surface of the frame-shaped insulating tape 14, a semiconductor element mounting portion 16 that bends (downsets) downward where the semiconductor element 15 is mounted
A heat sink 16 having d is thermocompression bonded.

A large number of rectangular cutout holes 17 including four corners are punched at predetermined intervals all over the outer edge portion 16a of the heat sink 16, and the outer edge portion 16a is heated by the frame-shaped insulating tape 14. A frame-shaped flat portion 16b to be crimped is provided on the outside, and is bent in a stepped shape through a large number of support leads 16c formed between the respective cutout holes 17. The bending amount of the heat sink 16 is set so that the upper width A and the lower width B of the molded body 36 are substantially equal when the semiconductor element 15 is mounted on the semiconductor element mounting portion 16d (see FIG. 3). As shown in FIG. 3, on the upper surface of the bottom of the heat sink 16 via the bond 18,
The semiconductor element 15 is mounted. Further, the inner leads 13 and the electrodes of the semiconductor element 15 are connected by the wires 19, and the semiconductor element 15 and the semiconductor element mounting portion 16 are connected.
d is resin-molded by the mold body 20. The outer leads 21 projecting outward from the four sides of the mold body 20 are formed into a gauring shape (FIG. 1).
See also).

Next, a method of manufacturing the semiconductor device 10 according to one embodiment of the present invention will be described with reference to FIGS. Figure 4
As shown in (a), the strip material of the laminated lead frame L is punched by a die to provide an intermediate lead frame body 11 having a large number of leads 12. At this time, the tips of all the inner leads 13 are connected by the connecting portion 11a having a substantially rectangular shape. Next, as shown in FIG. 4 (b), the nozzle 23 of the transfer head 22 adsorbs the substantially rectangular insulating tape 14A made of a thermoplastic insulating adhesive, and this is shown in FIG. 4 (a). The lead frame body 11 is bonded to the bonding area a. As a result, the outer edge of the insulating tape 14A is adhered to the tip of the inner lead 13. Next, as shown in FIG. 4 (c), the connecting portion 11a is punched and removed by a punching die 25 having a punching tool 24 so that the end surfaces of the tips of the inner leads 13 and the frame-shaped insulating tape 14 are left. After that, the end face of the inner lead 13 and the end face of the frame-shaped insulating tape 14 are subjected to a shaving process, and the lead frame body 11 having the frame-shaped insulating tape 14 is provided on the tip of the inner lead 13 as a continuous strip. To be

On the other hand, in parallel with the formation of the lead frame 11, as shown in FIG. 5A, an outer frame and an inner frame having a support tab for supporting the heat sink 16 from a required strip 26 and a pilot hole. And a plurality of punches (blades) are punched by an upper die 28 and a lower die 29 having punch blocks 27 arranged in a frame shape at regular intervals, and a large number of punches are provided on the outer edge portion 16a of the heat sink 16. The notch 17 is perforated to form the support lead 16c and the frame-shaped flat portion 16
b, heat sink 16 having semiconductor element mounting portion 16d
A continuous strip 26a is provided (see FIG. 5B). Then, as shown in FIG. 5B, the strip 22a is pressed by the upper and lower molds 30 and 31 having a downset punch and a die, the support lead 16c is bent downward, and the flat portion 16b and the semiconductor mounting portion are bent. 16d and a step having a predetermined bending amount are provided. At this time, since the semiconductor element mounting portion 16d is bent at the support lead 16c portion of the outer edge portion 16a having the cutout hole 17, the frame-shaped flat portion 16b and the semiconductor element mounting portion 16d with almost no distortion are formed. Then, as shown in FIG.
The heat sink 16 formed on 6a is cut by the punch 32 provided on the upper die 30a at the support tab to separate the heat sink 16.

Then, the heat sink 16 is attached as shown in FIG.
The transfer head 33 is sucked up and picked up by the nozzle 34 of the transfer head 33, the transfer head 33 is moved onto the lead frame main body 11 and the nozzle 34 is moved up and down, and the flat portion 16b of the heat sink 16 is transferred onto the frame-shaped insulating tape 14. Place on. Next, as shown in FIG. 6B, the lead frame body 11 is placed on the thermocompression bonding table 35, and the heatsink 16 is applied from above by a frame-shaped thermocompression bonding element 37 provided on the lower surface of the head 36. By pressing the flat part 16b of
The heat sink 16 is thermocompression-bonded to the tip portions of the inner leads 13 to manufacture the laminated lead frame L shown by the solid lines in FIGS. 1 and 3.

Then, the manufactured laminated lead frame L is turned upside down (see FIG. 7 (a)), and then FIG.
As shown in (b), the nozzle 39 of the bond coating device 38 is provided on the upper surface of the semiconductor element mounting portion 16 d of the heat sink 16.
Then, the bond 18 is dropped and applied. Next, as shown in FIG. 8A, the semiconductor element 15 housed in the tape feeder 40 is adsorbed by the nozzle 42 of the transfer head 41 to be picked up, and then the transfer head 41 is attached to the laminated lead frame L. By elevating and lowering on the heat sink 16, the semiconductor element 15 is mounted on the semiconductor element mounting portion 16 d of the heat sink 16 via the bond 18. Then, as shown in FIG. 8B, the horn 44 of the wire bonder 43 is moved up and down to connect the wire bonding area of the inner lead 13 and the electrode of the semiconductor element 15 to the wire 1.
9 connect to form an electrical continuity circuit.

Thereafter, as shown in FIG. 8C, the upper and lower dies 46 and 47 of the molding device 45 are interposed between the upper and lower dies 46 and 47, and the upper and lower dies 46 and 47 are fitted to each other to form a lower die. A mold resin is injected into the mold through the injection hole 48 of 47 to form the semiconductor element 15 and the semiconductor element mounting portion 1.
6d is resin-molded to provide a molded body 20. At the time of resin molding of the mounting portion of the semiconductor element 15, as shown in FIG. 3, the bending amount can be set so that the upper width A and the lower width B of the molded body 20 are substantially equal to each other. It is possible to prevent a filling defect of the mold resin due to the difference in the flow. Next, as shown in FIG. 9A, the laminated lead frame L is provided between the upper die 50 and the lower die 51 having the cutting blades 49 protruding from the lower surface.
By interposing the upper and lower dies 50 and 51 with each other interposed, the tips of the outer leads 21 are cut from the laminated lead frame L. Next, as shown in FIG. 9B,
By fitting the upper and lower molds 52 and 53 and bending and forming the outer lead 21 into a gauling shape, as shown in FIG.
The semiconductor device 10 shown in 3 is manufactured.

Thus, the flat portion 1 of the heat sink 16 is
6b through the frame-shaped insulating tape 14 to the inner lead 1
By thermocompression bonding to 3, the heatsink 16 becomes significantly firmer than the one in which the inner leads 13 are connected only by the frame-shaped insulating tape 14 as in the conventional case, and the inner leads 13 are prevented from rising and falling or shifting. As a result, the flatness and the positional accuracy can be improved, and the stability of the inner lead 13 and the semiconductor element mounting portion 16d against pulling at the time of forming the outer lead 21 is improved. Moreover, since the inner leads 13 are firmly thermocompression-bonded to the frame-shaped flat portion 16b through the frame-shaped insulating tape 14 in this manner, the heat sink 16 can be fixed without heat treatment for removing the residual stress of the leads 12. It is possible to prevent thermal deformation of the inner lead 13 when it is thermocompression bonded to the inner lead 13, and thus it is possible to reduce the equipment cost required for the heat treatment and the working time.

Although the embodiment of the present invention has been described above, the present invention is not limited to this embodiment and is included in the present invention as long as it does not depart from the gist. For example, the method of manufacturing the laminated lead frame is not limited to that of the embodiment. For example, as shown in FIG. 2, the adhesive portion and the heat sink may be sequentially attached to the lower surface of the tip portion of the inner lead. The manufacturing method such as manufacturing may be any method or procedure. Further, in the embodiment, the transfer head was used to transfer the insulating tape and the heat sink, but the lead frame body and the strip shape are formed at either the upper or lower part of the predetermined position in the manufacturing process of the laminated lead frame. The insulating tape and the heat sink may be formed by intersecting and crimping a continuous strip.
Furthermore, in the embodiment, a large number of cutout holes are provided in the outer edge portion of the heat sink in the entire area of the outer edge portion. However, without being limited to this, at least each corner portion of the outer edge portion may be provided. Absent.

[0020]

As described above, the semiconductor device and the method of manufacturing the same according to the first and second aspects are such that the support leads in the portion between the cutout holes in the outer edge portion of the heat sink have a frame shape with almost no distortion outside the outer edge portion. Since it is bent leaving the flat part,
Improves stability against thermal stress. Also, by thermocompression-bonding the flat part of the heat sink to the inner leads via the insulating tape, the connection between the inner leads is significantly solid compared to the conventional case where the inner leads were connected only by the insulating tape, and Since the ups and downs and the deviation are eliminated, the flatness and the positional accuracy can be improved, and the stability of the inner lead and the semiconductor element mounting portion against the pulling due to the forming of the outer lead is improved. Moreover, since the inner lead is firmly thermocompression bonded to the frame-shaped flat portion via the insulating tape,
It is possible to reduce the equipment cost and work time required for heat treatment to remove the residual stress of the leads. Further, since the inner lead is fixed by the frame-shaped flat portion, it is possible to prevent the inner lead from being pulled when forming the outer lead. Furthermore, since the inner leads are fixed by the frame-shaped flat portion, cracks generated in the resin package can be prevented and the reliability of the semiconductor device can be improved.

[Brief description of drawings]

FIG. 1 is an enlarged perspective view of a semiconductor device according to an embodiment of the present invention and a semiconductor device according to a manufacturing method thereof.

FIG. 2 is an exploded perspective view of the lead frame.

FIG. 3 is a sectional view of the same.

FIG. 4A is a perspective view of the lead frame body that has been punched. (B) It is a perspective view of the state which attached the tip part of the same inner lead, and the connection part which connected the tip by the insulating tape. (C) It is a perspective view which removed the connection part which connected the tip of the same inner lead.

FIG. 5 (a) is a perspective view of the heat sink during punching of a required shape. (B) It is sectional drawing in the bending process of the same heat sink. (C) A sectional view of the heat sink during punching.

FIG. 6A is a perspective view of the lead frame body while the heat sink is being mounted. (B) It is sectional drawing during thermocompression bonding of the heat sink to the lead frame main body.

FIG. 7A is a cross-sectional view of the inverted lead frame. (B) It is sectional drawing in the process of apply | coating a bond on the semiconductor element mounting part of the same heat sink.

FIG. 8A is a sectional view of the heat sink during mounting of the semiconductor element on the semiconductor element mounting portion. (B) It is sectional drawing after wire connection of the same inner lead and the electrode of a semiconductor element. (C) It is sectional drawing after resin molding of the mounting part of the same semiconductor element.

FIG. 9 (a) is a cross-sectional view of the inner lead after cutting the tip thereof. (B) A sectional view of the outer lead during forming.

FIG. 10 is an exploded perspective view of a conventional lead frame.

FIG. 11 is a sectional view of the same.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Semiconductor device 11 Lead frame main body 11a Connection part 12 Lead 13 Inner lead 14 Frame type insulating tape (joint part) 14A Insulating tape 15 Semiconductor element 16 Heat sink 16a Outer edge 16b Flat part 16c Support lead 16d Semiconductor element mounting part 17 Notch hole 18 Bond 19 Wire 20 Molded body 21 Outer lead 22 Transfer head 23 Nozzle 24 Blade 25 Cutting die 26 Article 26a Article 27 Punch block 28 Upper die 29 Lower die 30 Upper die 31 Lower die 32 Blade 33 Transfer head 34 Nozzle 35 Thermocompression bonding table 36 Head 37 Thermocompression bonding element 38 Bond coating device 39 Nozzle 40 Tape feeder 41 Transfer head 42 Nozzle 43 Wire bonder 44 Torch 45 Molding device 46 Upper mold 47 Lower mold 48 Injection hole 49 Blade 50 Upper mold 51 Lower mold 52 Upper mold 53 Lower mold L Stackable lead frame

Claims (2)

[Claims] 1. A large number of leads, a frame-shaped joint portion made of an insulating adhesive material for collectively connecting inner leads of the leads, and an outer edge portion having cutout holes at least at respective corners, A heat sink having a semiconductor element mounting portion in which a frame-shaped flat portion thermocompression bonded to the joint portion is provided outside and bent in a step shape, a semiconductor element mounted on the semiconductor element mounting portion of the heat sink, and the semiconductor A semiconductor device comprising: a wire connecting an electrode of an element and the inner lead; and a mold body for resin-molding the semiconductor element and its mounting portion. 2. A blank for a lead frame is punched out,
An inner lead frame body in which the tips of the inner leads of a large number of leads are connected by a connecting portion is provided, and an insulating tape made of an insulating adhesive is adhered to at least one surface of the tip portion of the inner leads and the connecting portion. Then, the connecting portion is punched out, the tips of the inner leads are cut, and a frame-shaped joint portion made of the insulating tape for collectively connecting the inner leads is provided. On the other hand, a semiconductor element mounting portion is provided. An outer edge portion of the heat sink having at least each corner portion provided with a cutout hole is bent in a step shape by providing a frame-shaped flat portion on the outside, and then the flat portion of the heat sink is connected to the flat portion through the joint portion. It is joined to the inner lead of the lead frame body, and then the semiconductor element is mounted on the semiconductor element mounting portion of the heat sink, and the electrode of the semiconductor element is mounted. Wherein the inner leads connected by wires, then, a method of manufacturing a semiconductor device, characterized in that the resin molding by a mold member said semiconductor element and said semiconductor element mounting portion.