KR100357878B1 - mold for manufacturing semiconductor package - Google Patents

Abstract

The present invention relates to a mold for manufacturing a semiconductor package, in order to eliminate the phenomenon that the semiconductor chip mounted on the substrate is cracked by the pressure of the encapsulant during the encapsulation process, a runner and a gate through which the encapsulant flows are formed. A top die in communication with the gate, the top die having a cavity of a predetermined space; In a mold for a semiconductor package including a bottom die in which a cavity having a predetermined space is formed in a region corresponding to a cavity of the top die to be seated and molded with a semiconductor chip bonded thereto, wherein the cavity of the bottom die is in the sealing process during the sealing process. Pressure equalization means is further formed so that the pressure received by the bottom of the straight is constant.

Description

Mold for manufacturing semiconductor package

The present invention relates to a mold for manufacturing a semiconductor package, and more particularly, to a mold for manufacturing a semiconductor package capable of removing a phenomenon in which a semiconductor chip mounted on a substrate is cracked due to the pressure of the encapsulant during the sealing process. .

The process of manufacturing a semiconductor package, such as a general ball grid array or pin grid array, includes a sawing step of cutting and inspecting a plurality of semiconductor chips formed on a wafer individually. Attaching the semiconductor chip to a substrate or lead frame using an adhesive; and placing the material on a heater block, and then entering / exiting the semiconductor chip using a conductive wire. A wire bonding step of connecting the output pad and the bond finger end of the substrate, and protecting the wire-bonded semiconductor chip, the conductive wire, etc. from the external environment, electrically insulated, and generated during operation of the semiconductor chip. Efficiently dissipate the heat, and molding step (molding) to form an encapsulant for easy mounting on the motherboard (mother board) Is done.

Here, the molding method using the encapsulant may be regarded as the core of the semiconductor package manufacturing step. The molding method using the encapsulant is the most commonly used in the semiconductor molding process because it is simpler and more productive than any other processing method. The encapsulant usually uses an epoxy molding compound, which is inferior in terms of thermal stability and reliability compared to ceramic, but is inexpensive and highly productive, so most encapsulants used in semiconductor packages today are The epoxy molding compound.

3 and 4 show a mold and an encapsulation state for performing such a process. First, the mold is largely composed of a transfer ram, a top die, and a bottom die, which will be described below.

First, a transfer ram 30 is provided to receive a force from a predetermined press (not shown) and to push the encapsulant 40 in a high melt state in a predetermined direction.

On the other hand, the top die 10 is lowered in the state where the transfer ram 30 is inserted to form a ram port 11 of a predetermined space so that the encapsulant 40 of the high-melting body located in the lower portion flows in a predetermined direction. It is.

The plurality of runners 12 and the gate 13 are connected to the ram port 11 of the top die 10 so that the encapsulant 40 softened by the pressing force of the transfer ram 30 may flow in a predetermined direction. ) Is formed.

In addition, the plurality of cavities 14 and 24 having a predetermined space are formed in the top die 10 and the bottom die 20 so that the substrates on which the semiconductor chips are mounted may be located in communication with the gate 13. .

Here, the top die 10 and the bottom die 20 have a heat cartridge (not shown) or the like as a heating means so as to soften the high-melting encapsulant 40 easily, and a plurality of air vents 15 are provided. ) Is formed so that the gas and air of the encapsulant 40 flowing out can be discharged to the outside of the cavities 14 and 24.

On the other hand, since the substrate 70 to which the semiconductor chip 60 is bonded recently uses a very thin and flexible material such as a polyimide tape or a polyimide film, as shown in FIGS. 5A and 5B. After bonding and curing the semiconductor chip 60 with the adhesive 80 to the substrate 70, the phenomenon that the substrate 70 is bent in a convex shape (Fig. 5A) or a concave shape (Fig. 5B) frequently occurs. . That is, since the thermal expansion coefficients between the semiconductor chip 60, the adhesive 80, and the substrate 70 are different from each other, and the substrate 70 is very thin, as shown in the figure after being supplied with a constant temperature, it is convex. The recess 70 is bent in a concave shape. In the figure, reference numeral 90 denotes a conductive wire.

Substrate 70 is bent as described above is seated between the cavity (14, 24) of the top die 10 and the bottom die 20, a very fatal problem occurs during the sealing process. That is, when the substrate 70 is bent concave as described above, no problem occurs, but when the substrate is bent convex, an air layer is formed between the bottom die 20 and the substrate 70 of the bottom surface of the semiconductor chip 60. As the air layer does not escape to the other side, the semiconductor chip 60 is cracked due to the pressure imbalance between the encapsulant 40 and the mold in direct contact with the air layer and the substrate.

In more detail, in the case of the recessed substrate 70, the air layer between the substrate 70 and the cavity 24 of the bottom die 20 easily escapes to the outside, so that no problem occurs, but the convex shape is convex. In this case, a predetermined air layer is confined between the substrate 70 and the cavity 24 of the bottom die 20 and is expanded by various heats provided during the encapsulation process, and at the same time, the encapsulant 40 is pressed at a high pressure. do. On the other hand, the air layer is not formed and a constant pressure also acts on the substrate 70 in direct contact with the bottom surface of the cavity 24 of the bottom die 40. However, the pressure acting between the region of the substrate 70 where the air layer is formed on the bottom surface and the substrate 70 which is in direct contact with the bottom surface of the cavity 24 of the bottom die 20 is completely different and thus is caused by pressure imbalance. In the semiconductor chip 60 bonded to the straight 70, the pressure received by the center and the pressure received by the inner circumference are different, resulting in cracks.

In Fig. 4, the thickness of the arrow indicates the magnitude of the pressure.

Therefore, the present invention has been made to solve the above-mentioned conventional problems, it is possible to eliminate the phenomenon that the semiconductor chip cracks due to the imbalance of the pressure of the encapsulant and the air layer pressure trapped between the substrate and the bottom die during the sealing process. To provide a mold for manufacturing a semiconductor package.

1A and 1B are sectional views showing the mold for manufacturing a semiconductor package according to the present invention, and a sectional view showing the main parts thereof.

Figure 2 is a state diagram showing a state in which the semiconductor package is mounted and molded in the mold according to the present invention.

3 is a cross-sectional view showing a mold for manufacturing a conventional semiconductor package.

4 is a state diagram illustrating a state in which a semiconductor package is mounted and molded in a conventional mold.

5A and 5B are diagrams showing a state in which a substrate having semiconductor chips is bent in a convex or concave shape.

-Description of the main symbols in the drawings-

10; Top die 12; Runner

13; Gate 20; Bottom die

14,24; Cavity 30; Transfer ram

60; Semiconductor chip 70; Substrate

80; Adhesive 90; Conductive Wire

101; Implant 102; fluid

103; Polyimide film

In order to achieve the above object, a mold for manufacturing a semiconductor package according to the present invention includes a runner and a gate through which an encapsulant flows, and a top die having a cavity of a predetermined space in communication with the gate; In a mold for a semiconductor package including a bottom die in which a cavity having a predetermined space is formed in a region corresponding to a cavity of the top die to be seated and molded with a semiconductor chip bonded thereto, wherein the cavity of the bottom die is in the sealing process during the sealing process. It is characterized in that the pressure homogenizing means is further formed so that the pressure received by the bottom of the straight becomes constant.

Here, the pressure homogenization means may be a soft implant molded into any one of silicon (silicone), heat resistant synthetic resin, polyimide (polyimide) or a combination thereof.

The pressure homogenizing means may be a fluid in which a fluid is placed in a cavity of a bottom die and sealed with a polyimide film or the like.

As described above, according to the mold for manufacturing a semiconductor package according to the present invention, when the sealing material is pressed at a constant pressure on the upper surface of the substrate by the pressure homogenizing means, ie, a soft implant or fluid having a change in appearance, is placed on the bottom of the substrate. At the same time, the pressure homogenization means located at the bottom of the substrate is in close contact with the bottom of the substrate and at the same time, the pressure toward the substrate is uniformed according to Pascal's principle, thus minimizing the stress caused by the pressure unbalance. The crack phenomenon of the semiconductor chip adhered to the straight line can be suppressed.

Here, Pascal's principle refers to the law that when pressure is applied to a part of a stationary fluid in a closed container, the pressure is transmitted to all parts of the fluid without changing its strength.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings such that those skilled in the art can easily implement the present invention.

1A and 1B are sectional views showing the mold for manufacturing a semiconductor package according to the present invention, and a sectional view showing the main parts thereof.

As in the prior art, the mold according to the present invention also includes a transfer ram 30, a top die 10, and a bottom die 20.

First, a transfer ram 30 is provided to receive a force from a predetermined press (not shown) and to push the encapsulant 40 in a high melt state in a predetermined direction, and the top die 10 includes the top die 10. Ramport 11 of a predetermined space is formed to descend in the state in which the transfer ram 30 is inserted to flow the encapsulant 40 of the high melt body located below the top ram 10, the top die 10 A plurality of runners 12 and gates 13 are formed to be connected to the ram port 11 so that the encapsulant 40 softened by the pressing force of the transfer ram 30 may flow in a predetermined direction. In addition, the plurality of cavities 14 having a predetermined space may be connected to the gate 13 so that the substrate 70 having the semiconductor chip 60 mounted thereon may be located on the top die 10 and the bottom die 20. 24 is formed, and this structure is the same as in the prior art.

The present invention is characterized in that the cavity 24 of the bottom die 20 is further formed pressure equalization means that can be changed in appearance so that the pressure received by the bottom of the substrate 70 during the sealing process is uniform.

Here, it is preferable that the pressure homogenizing means forms and positions the depth of the cavity 24 formed in the bottom die 20 to be deeper than before.

The pressure homogenizing means may be a soft implant 101 formed of any one of silicone, heat-resistant synthetic resin (for example, Teflon (trade name)), polyimide, or a combination thereof, and the material thereof. It is not intended to limit.

In addition, the pressure homogenizing means is more preferably put the fluid 102 in the cavity 24 of the bottom die 20, the upper portion is sealed with a polyimide film 103 or the like so as not to flow out. This is because Pascal's principle is better applied to fluids or fluids as described above.

FIG. 2 is a state diagram illustrating a state in which a semiconductor package, that is, a substrate having a semiconductor chip bonded thereto is mounted and molded in a mold according to the present invention.

As illustrated, the substrates 70 and the semiconductor chips 60 are disposed in the cavities 14 and 24 provided between the top die 10 and the bottom die 20. When the encapsulant 40 flows into the cavities 14 and 24 in this state, the upper portion of the semiconductor chip 60 and the substrate 70 is subjected to high temperature and high pressure by the encapsulant 40.

On the other hand, at this time by the pressure homogenization means, that is, the soft prosthesis 101 or the fluid 102 is located in the cavity 24 of the bottom die 20, the appearance is along the bent shape of the substrate 70 By changing, the pressure acts toward all the bottoms of the substrate 70 by the principle of Pascal while at the same time being in close contact with or near the bottom of the substrate 70.

Therefore, the pressure imbalance does not occur on the bottom of the substrate as in the prior art, and the semiconductor chip is also subjected to uniform pressure from the encapsulant to prevent the semiconductor chip from cracking.

As described above, although the present invention has been described with reference to the above embodiments, the present invention is not limited thereto, and various modified embodiments may be possible without departing from the scope and spirit of the present invention.

As described above, according to the mold for manufacturing a semiconductor package according to the present invention, when the sealing material is pressed at a constant pressure on the upper surface of the substrate by the pressure homogenizing means, ie, a soft implant or fluid having a change in appearance, is placed on the bottom of the substrate. In addition, the pressure homogenization means located at the bottom of the substrate is in close contact with the bottom of the substrate and at the same time the pressure toward the substrate is uniform, thus minimizing the stress caused by the unbalance of pressure and eventually cracking the semiconductor chip bonded to the substrate. It is effective in suppressing the phenomenon.

Claims (3)

A top die having a runner and a gate through which the encapsulant flows, and having a cavity in a predetermined space communicating with the gate; In the mold for a semiconductor package comprising a bottom die formed with a cavity of a predetermined space so that the substrate is bonded to the substrate bonded to the region of the cavity of the top die, A mold for manufacturing a semiconductor package, characterized in that the pressure homogenizing means is further formed in the cavity of the bottom die so that the pressure applied to the bottom of the substrate is constant during the sealing process. The mold for manufacturing a semiconductor package according to claim 1, wherein the pressure homogenizing means is a soft prosthesis formed of any one of silicon, heat resistant synthetic resin, polyimide, or a combination thereof. The mold for manufacturing a semiconductor package according to claim 1, wherein the pressure homogenizing means is a fluid in which a fluid is placed in a cavity of a bottom die and sealed with a polyimide film.