KR980012308A - Ball Grid Array package with die pad - Google Patents

Abstract

The present invention provides a semiconductor device having a printed circuit board having a plurality of wiring patterns, a die pad having a plurality of grooves or through holes attached to an upper surface of the printed circuit board, a semiconductor chip having a plurality of bonding pads mounted on the die pad, A solder ball attached to the lower surface of the printed circuit board for electrical connection between the semiconductor chip and the outside, and an encapsulant for protecting the semiconductor chip and the wiring pattern formed on the upper surface of the printed circuit board The present invention provides a ball grid package having a die pad having a feature that increases the bonding force between the adhesive and the die pad to prevent occurrence of interface delamination and package cracking, .

Description

Ball Grid Array package with die pad

The present invention relates to a ball grid array package, and more particularly to a ball grid array package having a structure that increases the reliability of the package.

In recent years, various types of packages have been developed to cope with multi-pin and high integration of semiconductor devices. Among them, a new plastic package called a ball grid array package is gaining popularity as a package having a highly integrated or lead frame-free mounting form. Since the ball grid array package has a small footprint area such as a land pattern, highly integrated mounting is possible, and solder balls are used instead of leads connected to the external terminals, so that deflection or distortion caused by the presence of lead does not occur, With less loss, repetitive assembly processes and large placement tolerances, product yield can be increased.

The structure of such a ball grid array package (hereinafter referred to as "BGA package") will be described with reference to FIG.

1 is a cross-sectional view showing an embodiment of a conventional BGA package.

1, a semiconductor chip 760 is attached to an upper surface of a die pad 72 of a printed circuit board 70 by an adhesive 74. At this time, the printed circuit board 70 has multilayer wiring patterns 80, And wiring patterns 80 and 81 of different layers are connected to each other by via holes 86. The bonding pads 78 formed on the upper surface of the semiconductor chip 76, And an upper portion of the printed circuit board 70 is sealed with an epoxy molding resin 88 to protect the wiring pattern 80 formed on the upper surface of the printed circuit board 70 from the external environment. A solder ball 84 serving as an electrical connecting means is attached to the wiring pattern 81 on the lower surface of the semiconductor chip 100. [

In the above-described BGA package, moisture is absorbed in an adhesive used for mounting in a bonding interface between a semiconductor chip and a printed circuit board in a high-temperature and high-humidity environment, resulting in interfacial peeling. Particularly, in the reliability test for temperature and humidity, when a large amount of moisture is absorbed into the adhesive and the IR reflow process proceeds, the interface peeling occurs at the interface, and the cracks are caused by the epoxy molding resin, And propagates to the outside of the package through the inside of the printed circuit board. This is due to the weak adhesion between the adhesive and the die pad with gold micro-gold coating. As a result, the interface between the adhesive and the die pad becomes the weakest point of the BGA package. These cracks and interface delamination greatly reduce the quality of the package.

Accordingly, an object of the present invention is to provide a BGA package having improved reliability of a package by increasing a bonding force between an adhesive and a die pad when attaching a semiconductor chip and a printed circuit board with an adhesive.

FIG. 1 is a cross-sectional view of one embodiment of a ball grid array package according to the prior art; FIG.

FIG. 2 is a cross-sectional view of one embodiment of a ball grid array package having a grooved die pad according to the present invention; FIG.

FIG. 3 is an enlarged cross-sectional view of a die pad portion in an embodiment of a ball grid array package having a grooved die pad according to the present invention. FIG.

FIG. 4 is a perspective view of a die pad in one embodiment of a ball grid array package having a grooved die pad according to the present invention; FIG.

FIG. 5 is a cross-sectional view of a die pad portion in another embodiment of a ball grid array package having a die pad, according to another embodiment of the ball grid array package having a grooved die pad according to the present invention.

6 is a perspective view of a die pad in another embodiment of a ball grid array package having a grooved die pad according to the present invention.

FIG. 7 is a perspective view of a die pad in another embodiment of a ball grid array package having a die-punched die pad according to the present invention; FIG.

Fig. 8 is a sectional view for explaining a die pad portion of another embodiment of a ball grid array package having a die pad with a through-hole formed according to the present invention; Fig.

DESCRIPTION OF THE REFERENCE NUMERALS

10, 30, 60, 70: printed circuit board 12, 32, 52, 62, 72: die pad

13: Dimples 14, 34, 64, 74: Adhesive

16, 36, 66, 76: semiconductor chip 18, 78: bonding pad

24, 84: solder ball 26, 86: via hole

28, 48, 68, 88: Epoxy molding resin 33, 53: Groove

54, 87: heat release via hole 63: through hole

According to an aspect of the present invention, there is provided a BGA package including a printed circuit board having a plurality of layers formed with wiring patterns, a die pad having a plurality of grooves attached to the upper surface of the printed circuit board, A semiconductor chip having a plurality of bonding pads mounted thereon, a solder ball attached to a lower surface of the printed circuit board for electrical connection between the semiconductor chip and the outside, And an encapsulating portion for protecting the cap.

According to another aspect of the present invention, there is provided a BGA package including a printed circuit board having a plurality of layers formed with wiring patterns, a die pad having a plurality of through holes attached to an upper surface of the printed circuit board, A semiconductor chip having a plurality of bonding pads mounted on the die pad; a solder ball attached to a lower surface of the printed circuit board for electrical connection between the semiconductor chip and the outside; And a sealing portion for protecting the semiconductor chip with a pattern.

BGA package having a die pad according to the present invention will now be described in more detail with reference to the accompanying drawings.

FIG. 2 is a cross-sectional view showing an embodiment of a BGA package having a groove-formed die pad according to the present invention, FIG. 3 is a cross-sectional view of a BGA package having a groove- Fig. 4 is a perspective view showing a die pad in one embodiment of a ball grid array package having a grooved die pad according to the present invention. Fig.

2 and 3, the semiconductor chip 16 is mounted on the die pad 12 attached to the upper surface of the printed circuit board 10 by means of an adhesive 14. The bonding pads 18 formed on the upper surface of the semiconductor chip 16 and the wiring patterns 20 formed on the upper surface of the printed circuit board 10 are wire-bonded with the gold wires 22. The wiring pattern 20 formed on the upper surface of the printed circuit board 10 and the wiring pattern 21 formed on the lower surface of the printed circuit board 10 are electrically connected to each other through a via hole penetrating the printed circuit board 10. 26 are electrically connected to each other. An upper portion of the printed circuit board 10 is sealed with an epoxy molding resin 28 to protect the semiconductor chip 10, the gold wire 22 and the wiring pattern 20 from the external environment. At this time, a plurality of grooves such as dimples 13 are formed at a predetermined depth on the upper surface of the die pad 12. And the adhesive 14 enters the respective dimples 13. The dimple 13 is designed such that the upper inner width is smaller than the lower inner width.

Referring to FIG. 4, the dimples 13 formed on the die pad 12 are arranged symmetrically on the upper part of the die pad 12 as a whole. These dimples 13 may be formed by etching.

The area of contact with the adhesive increases when the semiconductor chip is mounted on the die pad having grooves as described above. An increase in the contact area increases the bonding force between the adhesive and the die pad. Further, the groove has a portion having a larger inner width than the upper inner width, so that the bonding force can be further increased. And the grooves are formed uniformly symmetrically on the upper surface of the die pad so that a balanced bonding strength between the adhesive and the die pad can be balanced.

FIG. 5 is a cross-sectional view showing a die pad portion in another embodiment of a BGA package having a groove-formed die pad according to the present invention, and FIG. 6 is a cross-sectional view illustrating another embodiment of a BGA package having a groove- In the example, it is a perspective view of a die pad.

Referring to FIGS. 5 and 6, grooves 33 are formed in a portion of the die pad 32 at regular intervals and in a longitudinal direction. The die pad 32 on which the groove 33 is formed can increase the contact area with the adhesive 34 to increase the bonding force.

7 is a perspective view showing a die pad in another embodiment of a BGA package having a grooved die pad according to the present invention.

7, grooves 53 are arranged on the upper part of the die pad 52 in a lattice shape in the transverse direction and the longitudinal direction. On the upper surface of the die pad 52 except for the groove 53, 54 are formed.

The groove formed on the die pad is decompressed through this path when the moisture absorbed in the adhesive is vaporized, and as a result, the occurrence of popcorn cracks can be prevented. It should be noted that since the heat generated during operation of the semiconductor chip is collected on the die pad of the plated copper and then released to the lower end of the printed circuit board through the heat release via hole, the package crack is advantageous in that the area of the groove is excessively widened The area of the die pad portion serving as a relatively thermal collecting plate is reduced, resulting in deterioration of thermal characteristics. Therefore, the width, shape and total length of the groove are preferably determined in consideration of the size of the semiconductor chip and the hygroscopicity of the adhesive to be used.

8 is a perspective view of a die pad in another embodiment of a BGA package having through-holes according to the present invention.

8, a plurality of through-holes 63 penetrating the die pad 63 are formed in the die pad 62 so as to have a larger inner width than the upper inner width. The semiconductor chip 66 and the die pad 62 are bonded together by an adhesive. At this time, the adhesive 64 is introduced into the through hole 63 of the die pad 62. Therefore, not only the chemical bonding force with the adhesive 64 but also the mechanical bonding force is applied, and the bonding force with the adhesive 64 is increased. As a result, the bonding force with the semiconductor chip 66 is increased.

Therefore, according to the structure of the present invention, there is an advantage that the bonding force between the adhesive and the die pad is increased to prevent the interface peeling and the occurrence of package cracks, thereby improving the long-term reliability of the semiconductor chip package.

Claims (8)

A semiconductor chip having a plurality of bonding pads mounted on the die pad; a semiconductor chip having a plurality of bonding pads mounted on the semiconductor chip; A solder ball attached to the lower surface of the printed circuit board for electrical connection to the outside, and an encapsulating portion for protecting the semiconductor chip and the wiring pattern formed on the upper surface of the printed circuit board. A ball grid array package with pads. 2. The ball grid array package of claim 1, wherein the grooves are in the form of a dimple. 2. The ball grid array package of claim 1, wherein the grooves are in the form of a groove. 3. The ball grid array package of claim 1 or 2, wherein the grooves are symmetrically arranged. 2. The ball grid array package of claim 1, wherein an upper inner width of the grooves is smaller than a lower inner width. The semiconductor device according to claim 1, further comprising: a printed circuit board having a plurality of layers on which the wiring patterns are formed; a die pad having a plurality of through holes attached to an upper surface of the printed circuit board; A solder ball attached to the lower surface of the printed circuit board for electrical connection between the semiconductor chip and the outside, and an encapsulant for protecting the semiconductor chip and the wiring pattern formed on the upper surface of the printed circuit board, Wherein the ball grid array package has a die pad. 7. The ball grid array package of claim 6, wherein the through-holes are symmetrical. 7. The double-grid array package of claim 6, wherein the top width of the through-holes is smaller than the bottom width. ※ Note: It is disclosed by the contents of the first application.