JP2000114553A - Semiconductor device and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To largely simplify the production process by reducing the number of processes requiring external force such as deburring, lead cutting, lead forming and so forth. SOLUTION: A semiconductor element 20 is mounted on the inner lead 25 of a lead frame. The inner lead 25 and tie bars 26 are resin-sealed to form a mold 24 so that part of the tie bars 26 are exposed outside. The mold 24 is cut along the side end so that the unnecessary part of the tie bar 26 is cut to form external terminals 29. At the same time, burr of the mold 24 is removed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a semiconductor device of a surface mount type in which a semiconductor element mounted on a lead frame is sealed with a resin, and a method of manufacturing the same. The present invention relates to a surface-mount type semiconductor device in which elements are sealed with a translucent resin.

[0002]

2. Description of the Related Art FIGS. 8 to 11 show the structure of a conventional surface mount type semiconductor device in which a semiconductor element 1 such as a light emitting element chip or a light receiving element chip is resin-sealed, and a state in the course of its manufacture. As shown in FIG. 8, the semiconductor element 1 is die-bonded to the header part 3 of the mounting lead frame 2, and the electrodes of the semiconductor element 1 are electrically connected to the bonding parts 5 of the connection lead frame 4 using Au wires 6. are doing.

[0003] As the structure of the lead frame 2, a plurality of inner leads 7 each having a header portion 3 formed at the tip, an outer lead 8 linearly connected to the inner lead 7, and an outer lead 8
And a tie bar 10 for supporting the inner lead 7 and the outer lead 8 between them. In the connection lead frame 4, the bonding part 5 is formed on the inner lead 7 instead of the header part 3, and the other parts have the same structure.

[0004] Next, as shown in FIG. 9, transfer molding is performed using a translucent resin, and each inner lead 7 is formed.
Is molded to form a mold body 11. At this time, the resin flash A
Occurs. This resin burr A is mechanically removed in the next step by blasting or the like.

[0005] As shown in FIG. 10, first, the tie bar 10 is cut along the inner lead 7 to remove the unnecessary portion B of the tie bar 10, and the tie bar cutting is completed. Next, the base C of the outer lead 8 is cut, and at the same time, lead forming is performed so that surface mounting can be performed, thereby completing an individual surface mounting type semiconductor device as shown in FIG. As a lead surface treatment, at the time of completion of the tie bar cutting, a treatment such as solder plating and solder coating is performed to improve solderability at the time of surface mounting.

[0006]

In the structure of a conventional surface-mount type semiconductor device, it is necessary to mechanically remove a blaster or the like from resin burrs generated around a molded body by transfer molding. A mechanical external force is applied to the body. Further, tie bar cutting, lead cutting and lead forming steps are required. That is, from the completion of molding to the completion of a single semiconductor device, at least three externally applied processes, such as a deburring process, a tie bar cutting process, a lead cutting process, and a lead forming process, are required. Is difficult. In addition, the adhesion between the lead frame and the mold body is deteriorated by the external force, and there is a possibility that moisture may infiltrate along the interface between them, and there is a problem in quality.

[0007] Here, Japanese Patent Application Laid-Open No. 6-97349 discloses a semiconductor device in which the surface of the inner lead is resin-sealed so as to be exposed to the outside of the molded body. By cutting the protruding portion, the resin burrs generated between the tie bar and the tie bar are removed, and the tie bar cutting step is eliminated. However, since the resin burrs are generated around the mold body, the resin burrs at this portion can be removed, but the other portions need to be deburred, so that the production process cannot be greatly simplified.

Further, Japanese Patent Application Laid-Open No. 9-83013 discloses that
An optical coupling device that bends the lead frame before molding, seals the resin so that the surface of the lead frame is exposed outside the molded body, and cuts off the excess lead frame that has come out of the molded body It has been disclosed. Also in this case, the tie bar cutting step is eliminated, but deburring still needs to be performed.

SUMMARY OF THE INVENTION In view of the above, it is an object of the present invention to provide a semiconductor device having a structure capable of greatly simplifying a production process by reducing the steps to which external force is applied and improving quality.

[0010]

Means for Solving the Problems According to the present invention, there is provided a lead frame having a semiconductor element mounted thereon, and a molded body formed by resin-sealing a part of the lead frame and the semiconductor element. A surface-mount type semiconductor device, wherein the lead frame has an inner lead for mounting the semiconductor element and a tie bar for supporting the inner lead, and a part of the tie bar is provided outside the mold body. It is an exposed external terminal.

Then, a semiconductor element is mounted on the inner lead of the lead frame, and the inner lead and the tie bar are resin-sealed so that a part of the tie bar is exposed to the outside to form a molded body. Manufactured by cutting along. Therefore, unnecessary portions of the tie bar are cut to form external terminals, and at the same time, the mold body is deburred.

This makes it possible to make the width of the external terminal substantially equal to the width of the molded body. If the width of the external terminals can be increased, the area of contact with the solder when surface-mounted on a mounting board increases, and soldering becomes easier.

[0013] As a lead frame for obtaining the above-mentioned semiconductor device, a plurality of inner leads sealed with resin by a mold body, a tie bar for supporting each inner lead, and a cradle provided in parallel with the outside of the tie bar are provided. ,
It comprises a plurality of outer leads for connecting the cradle and the tie bar, and the outer leads are arranged so as to correspond to gaps between adjacent mold bodies.

Further, the inner lead and the outer lead are arranged to be offset from each other with the tie bar interposed therebetween, and a cut is formed inside the tie bar corresponding to the outer lead. By adopting such a structure, it is only necessary to cut along the side edge of the mold body after the end of the mold,
Only one cut is required for the lead frame.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a surface mount type semiconductor device in which an optical semiconductor element such as a light emitting element chip or a light receiving element chip of the present invention is sealed with a resin. The semiconductor device includes a mounting lead frame 21 on which a semiconductor element 20 is mounted, a connection lead frame 23 electrically connected to electrodes of the semiconductor element 20 by wires 22, and a part of each of the lead frames 21 and 23. And a molded body 24 in which the semiconductor element 20 is sealed with a translucent resin.

As shown in FIG. 2, each of the lead frames 21 and 23 has a plurality of inner leads 25 covered with a mold body 24 and a tie bar 26 for supporting each inner lead 25.
And a cradle 27 provided in parallel with the outside of the tie bar 26, and a plurality of outer leads 28 connecting the cradle 27 and the tie bar 26. And tie bar 2
A part of 6 is exposed to the outside of the mold body 24 to form an external terminal 29.

The inner lead 25 and the outer lead 28 are alternately arranged inside and outside with the tie bar 26 interposed therebetween. At the tip of the inner lead 25, a header portion 30 is provided in the mounting lead frame 21, and a bonding portion 31 is provided in the connection lead frame 23. Also, an outer lead 28 is provided inside the tie bar 26.
The width of the cut 32 is slightly larger than the width of the outer lead 28. Here, the positions of the outer leads 28 and the cuts 32 correspond to the gaps between the adjacent mold bodies 24, as shown in FIG.

Next, a method of manufacturing the semiconductor device having the above structure will be described. First, as shown in FIG. 2, the mounting lead frame 21 and the connecting lead frame 23 are arranged in parallel,
The outer leads 28 and the cuts 32 are arranged so as to face each other. The semiconductor element 20 is die-bonded to the header part 30 of the mounting inner lead 25, and the electrode of the semiconductor element 20 and the bonding part 31 of the connection-side inner lead 25 are wire-bonded with the Au wire 22 to be electrically connected. I do.

Thereafter, as shown in FIG. 3, a part of each of the inner leads 25 and the tie bars 26 is transfer-molded with a translucent resin such as an epoxy resin to form a molded body 24. Here, the region to be molded is a region surrounded by a straight line connecting the sides 32a of the cuts 32 facing each other and a straight line connecting the inner sides 32b of the cuts 32 adjacent to each other, and a part of the inside of the tie bar 26 is included in this region. included. When molded in this manner, the resin burrs D are generated only in gaps between the adjacent mold bodies 24.

Then, as shown in FIG.
4, ie, the side 32 of the opposing cut 32
The tie bar 26 is cut along a straight line connecting a, and the unnecessary portion E of the tie bar 26 is removed. At this time, the resin burrs D, the tie bars 26, and the outer leads 28, which are indicated by hatched portions in the figure, are removed. By this one cut, the semiconductor devices are separated individually, and the resin burrs D on the side edges of the mold body 24 are also removed at the same time, whereby the semiconductor device shown in FIG. 1 is completed.

As described above, the resin burrs D generated between the adjacent mold bodies 24 generated by the molding and the tie bars 26 of the lead frames 21 and 23 can be cut at the same time. By only one process, an individual surface-mount type semiconductor device is completed. Therefore, the deburring step, the lead cutting and the lead forming step can be eliminated, and the production process can be greatly simplified, and the external force applied when processing the mold body 24 can be greatly reduced.

In the semiconductor device having the above structure, a part of the tie bar 26 is exposed to the outside of the molded body 24 to become an external terminal 29. The width of the external terminal 29 is
The width is almost the same. As a result, as shown in FIG. 5, when the semiconductor device is surface-mounted on the electrode pattern 36 of the mounting board 35 by solder reflow, the contact area with the solder 37 increases, as shown in FIG. Excellent in nature. In addition, since the external terminals 29 protrude from a position slightly higher than the bottom surface of the molded body 24, a gap is formed between the external terminals 29 and the mounting substrate 35, so that the solder 37 easily wraps around, and reliable connection with the electrode pattern 36 is possible. Becomes Further, when the electrode pattern 36 of the mounting board 35 is formed, the pattern corresponding region P for the external terminal 29 is wide, so that the pattern design can have a margin.

On the other hand, in the semiconductor device having the conventional structure, when the semiconductor device is surface-mounted on the mounting board 35 as shown in FIG.
Outer leads 8 of lead frames 2 and 4 to be external terminals
The width of the electrode pattern 36 depends on the mounting location.
Position is decided, and the pattern design must be concerned. In addition, since the lead frames 2 and 4 protrude largely outside the molded body 11, the mounting area becomes large. However, in the semiconductor device of the present invention, since the external terminals 29 do not largely protrude from the molded body 24, the mounting area becomes small. it can.

It should be noted that the present invention is not limited to the above embodiment, and it goes without saying that many modifications and changes can be made to the above embodiment within the scope of the present invention. In the above embodiment, the semiconductor device has a pair of external terminals, and the optical semiconductor element is sealed with a translucent resin. For example, the semiconductor device having a plurality of pairs of external terminals as shown in FIG. It is also possible to apply a frame structure.

[0025]

As is apparent from the above description, according to the present invention, a part of the lead frame having the tie bar is resin-sealed, and a part of the tie bar is exposed to the outside of the molded body to form an external terminal. Therefore, a surface-mount type semiconductor device can be manufactured only by one cutting step of the lead frame. At this time, resin burrs generated on the side edges of the mold body can be removed at the same time.

Therefore, each step such as deburring, lead cutting and lead forming can be omitted, and the production process can be simplified. In addition, since the number of steps to which an external force is applied during manufacturing is reduced, adverse effects due to the external force are reduced, and the quality of the product can be improved.

Here, as a lead frame, an outer lead is disposed so as to correspond to a gap between adjacent mold bodies, and the inner lead and the outer lead are displaced from each other with a tie bar interposed therebetween. ,
By adopting a structure in which cuts are formed corresponding to the outer leads, a surface mount type semiconductor device capable of forming external terminals and deburring at the same time by one cut can be obtained.

By using the tie bar for the external terminal, the width of the external terminal can be made as large as the width of the molded body. The allowable range of the positional deviation is widened, and the positioning becomes easy. Conversely, since the area where the electrode pattern corresponds to the external terminal is widened, the degree of freedom in pattern design of the mounting board is increased,
Higher density and smaller size of mounting board can be achieved. In addition, the area of the external terminals is increased, the contact area with the solder is increased, and the solderability is excellent.

[Brief description of the drawings]

FIG. 1 shows a semiconductor device according to an embodiment of the present invention;
(A) is a plan view, (b) is a front view

FIG. 2 is a plan view of a lead frame on which a semiconductor element is mounted.

FIG. 3 is a plan view of the lead frame after molding.

FIG. 4 is a plan view of the lead frame after tie-bar cutting.

5A and 5B show a state in which the semiconductor device is surface-mounted on a mounting board, wherein FIG. 5A is a plan view and FIG.

6A and 6B show a state in which a conventional semiconductor device is surface-mounted on a mounting board, wherein FIG. 6A is a plan view and FIG.

7A and 7B show a semiconductor device of another embodiment, wherein FIG. 7A is a plan view and FIG. 7B is a front view.

FIG. 8 is a plan view of a lead frame on which a conventional semiconductor element is mounted.

FIG. 9 is a plan view of the lead frame after molding.

FIG. 10 is a plan view of the lead frame after tie-bar cutting.

11A and 11B show a conventional semiconductor device, wherein FIG.
(B) is a front view

[Explanation of symbols]

 Reference Signs List 20 semiconductor element 21 mounting lead frame 23 connection lead frame 24 molded body 25 inner lead 26 tie bar 27 cradle 28 outer lead 29 external terminal 32 notch

Continued on the front page F term (reference) 4M109 AA01 BA01 CA21 DA07 DA10 DB04 EC11 FA04 GA01 5F041 AA42 AA43 DA17 DA41 DA91 5F061 AA01 BA01 CA21 CB13 DD12 EA13 FA01 5F088 BA18 JA02 JA06 5F089 AC11 AC21 CA20

Claims (7)

[Claims] 1. A surface-mount type semiconductor device comprising: a lead frame on which a semiconductor element is mounted; and a molded body obtained by sealing a part of the lead frame and the semiconductor element with a resin. The frame has an inner lead on which the semiconductor element is mounted, and a tie bar for supporting the inner lead, and a part of the tie bar is exposed to the outside of the molded body to serve as an external terminal. Semiconductor device. 2. A mounting lead frame on which a semiconductor element is mounted, a connection lead frame electrically connected by wires to electrodes of the semiconductor element, and a part of each lead frame and the semiconductor element being transparent. A surface-mount type semiconductor device comprising a molded body sealed with a conductive resin, wherein the lead frame has an inner lead for mounting the semiconductor element, and a tie bar for supporting the inner lead. And a part of the tie bar is exposed to the outside of the mold body to serve as an external terminal. 3. The semiconductor device according to claim 1, wherein the width of the external terminal is substantially equal to the width of the molded body. 4. A semiconductor device is mounted on the inner lead of a lead frame having an inner lead and a tie bar supporting the inner lead, and the inner lead and the tie bar are resin-sealed so that a part of the tie bar is exposed to the outside. A method of manufacturing a semiconductor device, comprising cutting an unnecessary portion of the tie bar and performing deburring at the same time by cutting along a side edge of the mold body by stopping the mold body. . 5. Using a lead frame in which a plurality of inner leads are arranged in parallel on one tie bar, mounting a semiconductor element on each inner lead to form a plurality of molded bodies, and forming a plurality of molded bodies between each molded body. 5. The method according to claim 4, wherein the tie bars are cut to separate the tie bars. 6. A plurality of inner leads which are resin-sealed by a mold body of a semiconductor device, a tie bar supporting each inner lead, a cradle provided in parallel outside the tie bar, and the cradle and the tie bar And a plurality of outer leads for connecting the outer leads,
A lead frame for a semiconductor device, wherein the lead frame is arranged to correspond to a gap between adjacent mold bodies. 7. The semiconductor according to claim 6, wherein the inner lead and the outer lead are arranged offset from each other with the tie bar interposed therebetween, and a cut is formed inside the tie bar corresponding to the outer lead. Equipment lead frame.