JPH07335815A - Lead frame and semiconductor device using the same - Google Patents

Abstract

(57) [Abstract] [Purpose] To improve the adhesion between the sealing resin and the die pad to obtain a highly reliable semiconductor device. In a lead frame used for a resin-sealed semiconductor device having a die pad on which a semiconductor chip is mounted, a cutout 12 is provided in the die pad, and the cutout 1 is provided.
The crushing portion 16 having a concave portion and a protrusion protruding outward from the bottom surface of the concave portion is provided at the edge portion of 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lead frame and a semiconductor device using the same.

[0002]

2. Description of the Related Art Adhesion between a die pad and a sealing resin is a problem in a resin sealing type semiconductor device. This is because the encapsulating resin has a hygroscopic property, so that when it is heated in the reflow process when mounting a semiconductor device on a substrate or the like, the moisture taken into the encapsulating resin is the interface between the back surface of the die pad and the encapsulating resin. This is because vaporization and expansion occur at the portions, and the die pad and the sealing resin may be peeled off or cracks may be generated in the sealing resin at the relevant portions. In particular, recently, since a large semiconductor chip is mounted and the package is thin, the above problems are likely to occur.

Therefore, various methods have been used to improve the adhesion between the die pad and the sealing resin. For example, there is a method in which the back surface of the die pad is subjected to dimple processing, or a through hole is provided in the die pad to improve sticking to the sealing resin. FIG. 13 shows a method of improving the adhesion between the die pad and the sealing resin by providing a circular hole 51 on the back surface of the die pad 50 and subjecting the inner peripheral edge of the hole 51 to a crushing process (Japanese Patent Laid-Open No. 1-278055). Bulletin). In this method, the punch 53 performs a crushing process in a cross shape, and
As shown in FIG. 4, by forming the protrusions 52 toward the inside of the holes 51, the protrusions 52 are less likely to be embedded in the sealing resin, and the adhesion between the sealing resin and the die pad 50 is improved.

FIG. 15 shows another conventional example for improving the adhesion between the die pad and the sealing resin. The die pad 50 is provided with a plurality of notches 54 in parallel to improve the adhesion between the die pad 50 and the sealing resin. This improves the adhesion between the die pad 50 and the sealing resin (Japanese Patent Laid-Open No. 4-307760).
Issue).

[0005]

As described above, the die pad has conventionally been subjected to various processes to improve the adhesion between the sealing resin and the die pad. However, in the conventional method, the die pad and the sealing resin have been improved. There was a case where the adhesion with was insufficient.
The present invention can further improve the adhesion between the die pad and the sealing resin, and even when a large-sized semiconductor chip is mounted, the sealing resin peels off or cracks occur in the sealing resin. An object of the present invention is to provide a highly reliable lead frame that can solve the problem of occurrence and a semiconductor device using the same.

[0006]

The present invention has the following constitution in order to achieve the above object. That is, in a lead frame used for a resin-sealed semiconductor device having a die pad on which a semiconductor chip is mounted, the die pad is provided with a through hole and / or a notch, and an edge portion of the through hole or the notch has a recess and It is characterized in that a crushed portion having a protrusion protruding outward from the bottom surface of the recess is provided. Further, the recess is provided across the die pad surface between adjacent through holes or notches. A semiconductor device in which a semiconductor chip is mounted on the lead frame and resin-sealed, wherein the semiconductor chip is mounted and resin-sealed on a surface of the die pad where the recess is not formed. Is characterized by. Also, a semiconductor device in which a semiconductor chip is mounted on the lead frame and resin-sealed, wherein the semiconductor chip is mounted and resin-sealed on a surface where the recess is formed by the die pad. And

[0007]

In the lead frame according to the present invention, the die pad is provided with the through hole and / or the notch so that the lower surface of the semiconductor chip and the encapsulating resin directly adhere to each other, whereby the adhesiveness between the semiconductor chip and the encapsulating resin is improved. In addition, the recesses and protrusions provided at the edges of the through holes or the notches further improve the clinging to the sealing resin and improve the adhesion between the sealing resin and the die pad.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 is a plan view showing an embodiment of a lead frame according to the present invention, and shows an enlarged view of a portion of a die pad 10 where adhesion with a sealing resin is a problem.
In the lead frame of this embodiment, a narrow cutout 12 is provided from both side edges of the die pad 10 toward the central portion, and a narrow support piece 14 is formed to extend on both sides. And
The crushed portions 16 are formed on the edges of each of the support pieces 14 in a scattered manner. Reference numeral 18 is a stage support bar connected to the die pad 10.

2 and 3 show a method of manufacturing the lead frame by press punching. FIG. 2 shows a state in which the slit holes 20 are formed in the lead frame material in accordance with the positions where the die pad 10 is formed. Then, as shown in FIG. 3, the edge portions of the slit holes 20 are punched by a punching process. 16 is formed. In these processes, it is preferable to connect the tip portions of the support pieces 14 that will be cut off in a later step to process the die pad 10 because deformation of the die pad 10 can be suppressed.

After the crushed portion 16 is formed, the connecting portion at the tip of the support piece 14 is cut off to remove the crushed portion 16, as shown in FIG.
As shown in, a die pad 10 having a plurality of cutouts 12 is obtained. When actually manufacturing a lead frame, the strip-shaped lead frame material is formed into a predetermined shape of the lead frame through a plurality of processing steps one after another.
The above-described processing of the slit hole 20 and the crushed portion 16 is performed by incorporating them in these series of processing steps.

Since the order in which the lead frame material is drawn out by the mold is appropriately set depending on the product, the processing for forming the slit hole 20 and the crushed portion 16 may be appropriately set according to the entire processing steps. In the above embodiment, the outer shape of the die pad 10 is formed, and then the slit hole 20 is removed. It is also possible to mold 10.

FIG. 4 shows a supporting piece 1 formed by the above method.
4 and the collapsed portion 16 are shown in an enlarged manner. The crushing portion 16 is composed of a concave portion 16a formed by crushing the edge portion of the support piece 14 with a punch, and a protruding portion 16b protruding outward from the bottom surface of the concave portion 16b in an eaves shape. This protrusion 16b
Has an effect of improving the adhesiveness between the die pad and the sealing resin when the semiconductor chip is mounted and resin-sealed.

FIG. 5 shows the semiconductor chip 22 on the die pad 10.
It is the figure which expanded and showed the cross section of the die pad 10 part in the state which mounted and resin-sealed. When the semiconductor chip 20 is mounted on the die pad 10, it is usually mounted with the surface on which the dimples have been processed outside (the back surface of the semiconductor chip mounting surface). Also in the case of the present embodiment, the die pad 10 is provided with the surface provided with the crushed portion 16 as the back surface of the mounting surface of the semiconductor chip 22.
The semiconductor chip 22 is mounted on.

The semiconductor chip 22 is supported by the support pieces 14 formed at regular intervals. When resin sealing is performed in this state, the sealing resin 24 enters the gap portion of the support piece 14 and hardens, as shown in FIG. 5, so that the lower surface of the semiconductor chip 22 and the sealing resin 24 directly adhere to each other. Semiconductor chip 2
The lower surface of the semiconductor chip 22 is usually coated, and the adhesion between the lower surface of the semiconductor chip 22 and the sealing resin 24 is
2 is better than the adhesion between the die pad 10 and
It is effective to prevent the peeling on the back surface of the die pad by providing the notch 12 in the die pad 10 as in this embodiment so that the semiconductor chip 22 and the sealing resin 24 directly adhere to each other.

Further, in the case of the lead frame of the embodiment, since the sealing resin 24 enters between the supporting pieces 14 of the die pad 10 and is resin-sealed, the supporting pieces 14 are buried in the sealing resin 24. Therefore, the sticking property between the die pad 10 and the sealing resin 24 can be improved. Further, in the case of the present embodiment, as shown in FIG. 5, the protruding portion 16 b formed on the crushed portion 16 is embedded in the sealing resin 24 so as to be resin-sealed, so that the crushed portion 16 seals the die pad 10 and the die pad 10. It also has the effect of further improving the clinging to the resin 24.

In the above embodiment, the support pieces 14 are provided with the crushed portions 16 in a scattered manner, but as shown in FIG.
It is also possible to provide the crushed portion 16 relatively long along the edge of the ridge 4. Further, as shown in FIG. 7, when the notches 12 are provided in the die pad 10, it is possible to provide the notches 12 vertically and horizontally.
Also in this embodiment, the crushed portion 16 is provided on the edge of the support piece 14.
Is provided. Instead of providing the notches 12 in the die pad 10 as in these examples, through holes are provided in the die pad 10 as shown in FIG. 3 and the crushed portions 16 are provided at the edges of the through holes in a scattered manner. The same effect as that of the above-described embodiment can be obtained even in the case of the above, or in the case where the crushed portion 16 is provided relatively long along the edge portion (not shown).

By providing through holes in the die pad 10, the lower surface of the semiconductor chip 22 and the sealing resin 24 can be directly adhered to each other to improve the adhesion between the semiconductor chip 22 and the sealing resin 24. The crushed portion 16 provided at the edge portion of the can also obtain the effect of clinging between the sealing resin 24 and the die pad 10. However, when the through hole is provided, the area of the contact portion between the semiconductor chip 22 and the sealing resin 24 is limited as compared with the case where the notch 12 is formed.

FIG. 8 is a plan view showing another embodiment of the die pad 10 portion of the lead frame. Also in the lead frame of this embodiment, the notch 12 is provided in the die pad 10 and the crushed portion 16 is provided on the upper surface of the support piece 14, but unlike the above-described embodiment, the crushed portion is formed over the entire width of the upper surface of each support piece 14. 16 are provided.

FIG. 9 is an explanatory view showing a method for manufacturing the lead frame shown in FIG. 8, in which the die pad 10 is formed on the lead frame material and the slit holes 20 are provided, and then the supporting piece 1 is formed.
The whole widthwise direction of 4 is crushed with a punch and crushed part 1
6 is formed. In the case of this embodiment, all supporting pieces 1 at a time
It can be crushed using a punch that crosses 4. FIG. 10 shows the crushed portion 16 provided on the support piece 14.
In the case of the present embodiment, the recess 16a is formed in the entire width of the support piece 14 as shown in the figure, and the protrusion 16b extends outward from the bottom surface of the recess 16a.

FIG. 11 is an enlarged view of the die pad 10 in a state where the semiconductor chip 22 is mounted on the lead frame of this embodiment and resin-sealed. The figure is a cross-sectional view of the surface of the die pad 10 that passes through the crushed portion 16 on the support piece 14. Even when the semiconductor chip 22 is mounted on the lead frame of this embodiment, the crushed portion 16 can be provided on the back surface side of the mounting surface of the semiconductor chip 22 as shown in FIG. 5, but in FIG. An example in which the die pad 10 surface side provided is resin-sealed as the mounting surface of the semiconductor chip 22 is shown.

As described above, the crushing portion 16 is formed in the semiconductor chip 2
When the resin is sealed on the mounting surface side of No. 2, the recess 16a of the crushed portion 16 provided on the support piece 14 communicates with the upper surface of the support piece 14 in the width direction. When sealed, the sealing resin 24 enters the recess 16a, and the sealing resin 24 and the die pad 10 are suitably integrated.

Since the die pad 10 and the semiconductor chip 22 are strongly bonded by die attachment, if the sealing resin 24 is made to enter the recess 16a of the crushing portion 16 as described above and is integrally cured. Therefore, it becomes possible to effectively prevent peeling between the sealing resin 24 and the die pad 10. The method of mounting the semiconductor chip 22 on the surface on which the crushed portion 16 is formed can be applied to the case of the previous embodiment. However, the crushing unit 16
Since the crushing depth cannot always be deeper than the thickness of the support piece 14, when the recess 16a does not communicate in the width direction as in the present embodiment, the sealing resin 24 and the die pad 10 are not formed.
The effect of suppressing the peeling off with is weak.

When the crushed portion 16 is provided in the entire width direction of the support piece 14 as shown in FIG.
It is also possible to provide the crushing portion 16 on the other surface of 4. In this case, peeling of the sealing resin can be prevented by the action of both the surface on which the semiconductor chip 22 is mounted and the crushed portion provided on the back surface of this mounting surface.

In the above embodiment, the case of the lead frame manufactured by press working has been described.
In the case where the recess 16a that communicates in the width direction is provided on the upper surface of the substrate to prevent the die pad and the sealing resin from peeling off, the present invention can be applied to a lead frame manufactured by an etching method. FIG. 12 shows an example in which one surface of the support piece 14 is etched to form a recess 16a similar to that shown in FIG. Also in this embodiment, the surface where the recess 16a is formed is resin-sealed as the mounting surface of the semiconductor chip, so that the adhesion between the die pad and the sealing resin can be improved, and the semiconductor device is highly reliable. It becomes possible to do.

[0025]

As described above, according to the lead frame and the semiconductor device using the same of the present invention, it is possible to effectively improve the adhesion between the sealing resin and the die pad of the lead frame. Peeling of the die pad and the sealing resin or cracking of the sealing resin is preferably prevented, and a remarkable effect such as a highly reliable semiconductor device can be provided.

[Brief description of drawings]

FIG. 1 is a plan view showing an embodiment of a lead frame.

FIG. 2 is an explanatory diagram showing a method of manufacturing a lead frame.

FIG. 3 is an explanatory diagram showing a method of manufacturing a lead frame.

FIG. 4 is an enlarged perspective view showing a crushed portion provided on a support piece.

FIG. 5 is an explanatory view showing a state in which a semiconductor chip is mounted on a lead frame and resin-sealed.

FIG. 6 is an explanatory diagram showing another example of the crushing portion provided on the die pad.

FIG. 7 is an explanatory diagram showing another form of the die pad.

FIG. 8 is an explanatory diagram showing another example of forming a crushed portion provided on the die pad.

FIG. 9 is an explanatory diagram showing the method of manufacturing the lead frame.

FIG. 10 is an explanatory view showing an enlarged crushed portion provided on the support piece.

FIG. 11 is an explanatory diagram showing a state in which a semiconductor chip is mounted on a lead frame and resin-sealed.

FIG. 12 is an explanatory diagram showing an enlarged crushed portion provided on a support piece by an etching method.

FIG. 13 is an explanatory diagram showing an example of forming a conventional die pad.

FIG. 14 is an explanatory diagram showing a conventional die pad forming method.

FIG. 15 is an explanatory diagram showing another conventional example of a die pad.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Die pad 12 Notch 14 Support piece 16 Crushed portion 16a Recessed portion 16b Projection portion 20 Slit hole 22 Semiconductor chip 24 Sealing resin

Claims (4)

[Claims] 1. A lead frame used for a resin-sealed semiconductor device having a die pad on which a semiconductor chip is mounted, wherein the die pad is provided with a through hole and / or a notch, and an edge portion of the through hole or the notch, A lead frame comprising a crushed portion having a recess and a protrusion protruding outward from a bottom surface of the recess. 2. The lead frame according to claim 1, wherein the recess is provided across the die pad surface between adjacent through holes or notches. 3. A semiconductor device in which a semiconductor chip is mounted on the lead frame according to claim 1 or 2 and is resin-sealed, wherein the semiconductor chip is provided on a surface of the die pad where the recess is not formed. A semiconductor device which is mounted and resin-sealed. 4. A semiconductor device in which a semiconductor chip is mounted on a lead frame according to claim 2 and resin-sealed, wherein the semiconductor chip is mounted on a surface of the die pad on which the recess is formed. A semiconductor device characterized by being sealed.