JP2004096094A - Molding die used for manufacture bga package - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a suitable resin mold by preventing deformation such as warpage of a BGA package made of resin. <P>SOLUTION: In a molding die used for manufacturing a BGA package, which clamps a board 12 with the lower die 24, provided with a section setting the board 12 at a specified place, and with an upper die 26, provided with a cavity recessed section, sealing a semiconductor chip 10 with a resin, and is molded with the resin by filling a cavity 16 with resin, a heat insulating groove 32, which controls the heat conduction by changing the groove width or the depth of the grooves so that the resin filled in the cavity 16 is cured from the center first, is provided at the circumferencial position of the cavity 16 of the lower die 24 and/or the upper die 26. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a mold used for manufacturing a BGA package.
[0002]
[Prior art]
FIG. 13 shows a configuration of a conventional example of a BGA package. As shown in the figure, the BGA package is formed by mounting a semiconductor chip 6 on the upper surface of a substrate 5 and performing resin molding on one side. When such a BGA package is manufactured, usually, a semiconductor chip 6 is mounted on a substrate 5, and one surface of the substrate 5 is resin-molded, and then a solder ball 7 is bonded to a lower surface of the substrate 5 to obtain a product.
[0003]
[Problems to be solved by the invention]
Incidentally, there is a problem that the conventional BGA package is inferior in heat dissipation as compared with QFP or the like. This is because heat can be dissipated from the lead frame portion in a package using a metal lead frame such as QFP, whereas in the case of a BGA package, heat dissipation from the substrate is low because the substrate is an insulator. . Also, in the case of a BGA package, the area occupied by the mounted semiconductor chip is large relative to the package size, so that heat dissipation corresponding to the heat generated by the semiconductor chip cannot be obtained. This is because the surface area of the resin mold portion is reduced to about 25% or less as compared with QFP, so that heat radiation is limited.
[0004]
As another problem, as shown in FIG. 13, the BGA package is formed by resin molding only on one side of the substrate 5 and the area occupied by the resin molding area with respect to the entire area of the substrate 5 is large. The problem is that the substrate warps.
The present invention has been made in order to solve these problems, and in addition to solving the problem of heat dissipation in the conventional BGA package, it is possible to preferably manufacture a product in which the warpage of the BGA package is preferably prevented. It is an object of the present invention to provide a mold that can be used.
[0005]
[Means for Solving the Problems]
The present invention has the following configuration to achieve the above object.
That is, a BGA package in which a substrate is clamped by a lower die having a set portion for setting the substrate at a predetermined position and an upper die having a cavity concave portion for resin-sealing the semiconductor chip, and the cavity is filled with resin and molded with resin. In the mold used in the manufacture of the above, the width of the groove or the depth of the groove is changed around the cavity in the lower mold and / or the upper mold so that the resin filled in the cavity is cured from the center first. A heat insulating groove for controlling heat conduction.
In addition, by changing the groove width or the groove depth near the mold runner and / or the gate, heat conduction to the resin in the mold runner or the gate is suppressed more than to the resin filled in the cavity. A heat-insulating groove for improving the resin filling property from the mold runner and the gate to the cavity is provided.
In addition, the inner surface of the cavity concave portion in which the heat radiating plate is arranged is provided in a concave shape, and at the time of filling the resin, the heat radiating plate is warped outward to supply the resin excessively, and the heat radiating plate is returned to a flat surface by the resin shrink after the resin filling. It is characterized by the fact that it has been provided.
[0006]
[Action]
According to the mold used for manufacturing the BGA package according to the present invention, the heat conduction in the peripheral portion, the mold runner portion, and the gate portion of the package can be suppressed by providing the heat insulating groove in the mold. In addition, it is possible to promote the curing of the resin from the center of the package, and to obtain a BGA package without deformation such as warpage. Further, by resin molding together with the heat radiating plate, the resin is cured from the center of the cavity first by heat conduction from the heat radiating plate, thereby preventing deformation and manufacturing a highly reliable product.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The BGA package is formed by integrally molding a heatsink at the same time as one surface of the substrate is sealed with resin. FIG. 1 is an explanatory diagram showing a configuration of a mold used for manufacturing a BGA package. The figure shows a state in which a substrate 12 on which a semiconductor chip 10 is mounted is set together with a heat sink 14 in a cavity 16 of a mold. In the figure, reference numeral 18 denotes a pot, 20 denotes a plunger, and 22 denotes a mold runner and a gate for connecting the pot 18 and the cavity 16.
[0008]
The lower mold 24 is provided with a set portion for setting the substrate 12 at a predetermined position, and the substrate 12 is clamped by the upper mold 26 and the lower mold 24 each having a cavity concave portion for sealing the semiconductor chip 10 with a resin. The resin is molded by filling the inside. The lower die 24 is provided with a suction groove 25 for sucking and supporting the substrate 12. The suction groove 25 communicates with a vacuum suction mechanism. Further, the cavity concave portion of the upper die 26 is provided with a suction hole 28 at substantially the center of the concave surface, and the suction hole 28 is connected to a vacuum suction mechanism so that the heat sink 14 can be adsorbed on the inner surface of the cavity concave portion.
[0009]
In the present embodiment, as shown in FIG. 1, the inner surface of the cavity concave portion provided in the upper die 26 is formed in a concave shape in which the central portion is expanded. The reason why the cavity 16 is viewed in the thickness direction and the center portion is made thicker and the periphery thereof is made thinner is to minimize the warpage of the substrate 12 caused by the resin shrink during resin molding.
[0010]
The lower mold 24 and the upper mold 26 are provided with a heat insulating groove 30 for suppressing heat conduction around the cull, a heat insulating groove 32 for suppressing heat conduction around the package, and a heat insulating groove 34 for suppressing heat conduction at the gate part. . FIG. 2 shows a plan layout of the heat insulating grooves 30 and 32. These heat insulating grooves 30, 32, and 34 are provided with voids in the mold to suppress heat conduction acting on the molten resin at the time of filling the resin, and to suppress curing of the thermosetting resin, thereby enabling suitable resin molding. The purpose is to be.
[0011]
3 to 6 show how a BGA package is resin-molded using the above-mentioned mold.
FIG. 3 shows a state in which the substrate 12 is set on the lower mold 24 and the heat radiating plate 14 is set on the upper mold 26 with the mold opened. The substrate 12 is suction-supported in the cavity recess by the suction groove 25, and the heat dissipation plate 14 is suction-supported by the suction hole 28 on the inner surface of the cavity recess of the upper die 26. The resin tablet 40 is put into the pot 18.
[0012]
Next, the substrate 12 is clamped by the lower mold 24 and the upper mold 26, and the molten resin is pressure-fed into the cavity by the plunger 20. FIG. 4 shows how the plunger 20 fills the cavity with the molten resin 42. In the mold according to the embodiment, a protrusion is provided on the inner surface of the heat radiating plate 14 so that the resin is hardened from the center of the cavity first, so that the distance between the surface of the semiconductor chip 10 and the heat radiating plate 14 is narrowed, and the resin capacity between them is reduced. And heat conduction from the radiator plate 14 is facilitated to promote resin curing. As a result, the curing of the resin proceeds from the central portion in the package, and the influence of the resin shrink can be suppressed.
[0013]
The heat insulating grooves 30, 32, and 34 act to suppress heat conduction in the mold runner portion, the peripheral portion of the package, and the gate portion, and delay the resin curing in the peripheral portion of the mold runner and the package. The heat conduction by the heat insulating groove can be appropriately controlled by changing the groove width and the groove depth. For example, since the heat conduction becomes better when the heat insulating groove is shallower than when the heat insulating groove is deeper, resin curing can be promoted. The heat insulating groove 32 provided in the peripheral part of the package is intended to promote the resin curing from the central part of the package and suppress the action of the resin shrink.
[0014]
In the vicinity of the gate, heat insulating grooves 34 are provided around the top, bottom, left and right of the gate, so that heat conduction is suppressed and the curing at the gate is delayed. This enables the resin to be pumped by applying the resin pressure with the plunger 20 even after the resin filling in the cavity is almost completed and the resin curing in the cavity starts, so that good resin molding can be performed. In order to FIG. 5 shows a state in which the resin is almost completely filled in the cavity, and the resin is being molded while applying the resin pressure by the plunger 20.
[0015]
Although a heater for heating the mold is installed in the mold, the heater provided near the pot or the mold runner is turned on 100% when the resin tablet 40 is supplied, so that the resin tablet 40 is quickly turned on. After the resin tablet 40 is melted, the energization is suppressed to suppress the resin curing in the mold runner or the gate portion, and after the resin is filled into the cavity and the gate is closed, the energization is performed again. It is also effective to control the resin curing so as to accelerate the curing of the resin.
[0016]
As described above, in the embodiment, since the inner surface of the cavity concave portion of the upper die 26 has a concave shape, the heat radiation plate 14 is curved upward by the resin pressure when the resin is filled (FIG. 4). Due to the resin shrink at this time, it returns to a flat surface as shown in FIG. As described above, the method of filling the resin with the heat dissipation plate 14 in a warped shape is to make the heat dissipation plate 14 flat after the resin molding by making the amount of oversupplied resin equal to the amount of resin shrink due to the curing reaction of the resin. This makes it possible to prevent the package from warping.
[0017]
After resin molding, the molded product is taken out of the mold, and unnecessary resin portions such as the molded product runner 44 are removed to obtain a product (FIG. 6). The resin-molded product is a resin-molded product in which one surface of the substrate 12 is resin-molded by the mold resin 46, and the outer surface of the heat sink 14 is exposed on the outer surface of the mold resin 46. In this molded product, the heat radiation plate 14 is resin-molded integrally with the mold resin 46, so that the heat radiation effect of the heat radiation plate 14 can effectively improve the heat dissipation of the package. Further, by integrally forming the heat radiating plate 14, deformation such as warpage of the package can be prevented by the heat radiating plate 14, and the flatness of the substrate 12 can be obtained.
[0018]
In the mold of the present embodiment, the heat radiator 14 is set in the cavity of the mold and resin-molded in order to integrally mold the heat radiator 14 with the substrate 12. For this reason, in the above embodiment, the heat sink 14 is vacuum-adsorbed on the inner surface of the cavity and resin-molded. However, when the heat sink 14 is set in the cavity and resin-molded, a thin resin layer is formed on the outer surface of the heat sink 14. Can be a problem. 7 to 9 show examples of the configuration of a metal mold for resin molding without causing resin burrs.
[0019]
FIG. 7B shows a state in which the heat sink 14 is supported by vacuum suction on the inner surface of the cavity recess, and FIG. 7A is a partially enlarged view thereof. In this mold, a step 50 is provided on a portion of the inner surface of the cavity concave portion which comes into contact with the vicinity of the peripheral edge of the radiator plate 14, and a gap is provided between the outer surface of the peripheral portion of the heat radiator plate 14 and the inner surface of the cavity concave portion. This is an example of the configuration. The resin trap portion 52 allows the molten resin to slightly enter the outer surface of the heat sink 14 when the resin is filled, and the resin is hardened at the resin trap portion 52 so that the resin does not enter the heat sink 14 any more. By doing so, the occurrence of thin flash is prevented. The void portion of the resin trap portion 52 is about 0 to 0.2 mm, preferably about 0.05 to 0.2 mm. Reference numeral 28a denotes a suction groove for supporting the heat sink 14 by vacuum suction.
[0020]
FIG. 8 shows a configuration in which a set concave portion 50a for setting the heat sink 14 is provided on the inner surface of the cavity concave portion, and a gap is provided as a resin trap portion 54 between the wall surface of the set concave portion 50a and the side surface of the heat sink 14 to perform resin molding. This is an example. In this example, the resin filled in the resin trap portion 54 at the time of resin molding is hardened and the resin is prevented from flowing around the outer surface of the heat sink 14. In addition, the resin trap portion 54 is formed in a V-shaped cross section to provide a draft taper angle.
[0021]
The embodiment shown in FIG. 9 is an embodiment in which the heat sink 14 is exposed to almost the entire outer surface of the package and resin molding is performed. In this case, the size and shape of the surface on which the heat radiating plate 14 is arranged on the inner surface of the cavity concave portion substantially match the heat radiating plate 14 so that a slight gap is formed between the side surface of the heat radiating plate 14 and the side surface of the cavity concave portion. Perform resin molding. In the case of the present embodiment, the void acts as a resin trap, and resin can be molded while preventing the resin from flowing around the outer surface of the heat sink 14. FIG. 9A shows an example in which a resin mold is performed with the fracture surface side of the heat radiating plate 14 formed by press punching being the exposed surface side. When resin molding is performed with the fractured surface side outward as described above, there is an advantage that the heat radiation plate 14 is less likely to be separated from the mold resin because the fractured surface portion is formed in an inversely tapered shape.
[0022]
The mold of each of the above embodiments is characterized in that the heat sink 14 is arranged in the cavity recess provided in the upper mold 26 and resin molding is performed. In this case, the resin is cured from the center of the cavity first. For this purpose, the distance between the semiconductor chip 10 and the heat radiating plate 14 is narrowed to reduce the resin capacity, so that heat conduction is further promoted at the central portion. FIGS. 10, 11, and 12 show examples of the heat radiating plate 14 that can be suitably used for the BGA package with the heat radiating plate.
[0023]
The heat radiating plate 14 shown in FIG. 10 is an example in which a step-shaped projection 14a is provided at the center of the inner surface facing the semiconductor chip 10. As shown in FIG. 1, the semiconductor chip 10 is bonded to the substrate 12 at the outer edge thereof, so that a flat projection 14a is provided inside so as not to interfere with the bonding wires.
The heat radiating plate 14 shown in FIG. 11 has an example in which the projections 14a are provided so as to protrude in a mountain shape, and the heat radiating plate 14 shown in FIG. 12 has grooves in the diagonal direction of the projections 14a in the embodiment shown in FIG. It is an example. According to the heat radiating plate 14 shown in FIGS. 11 and 12, there is an advantage that the resin can be easily injected into the gap between the semiconductor chip 10 and the heat radiating plate 14 during resin molding, and the air can be easily removed.
[0024]
The protrusions 14a provided on the heat sink 14 reduce the capacity of the resin sandwiched between the semiconductor chip 10 and thereby promote the curing of the resin. Therefore, the design of the protrusions 14a is of course limited to the above example. Not something. For example, a method of providing a large number of small protrusions or a method of providing a plurality of protrusions linearly is also possible. The heat radiating plate 14 can be easily manufactured by press punching, and is useful in that the manufacturing cost is not required.
[0025]
【The invention's effect】
According to the mold used for manufacturing the BGA package according to the present invention, as described above, deformation such as warpage of the BGA package can be prevented, and suitable resin molding can be performed. In addition, the package is prevented from warping by being integrally formed with the heat radiating plate, so that a highly reliable BGA package can be easily manufactured.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram illustrating a configuration of an embodiment of a mold.
FIG. 2 is an explanatory diagram showing an example of the arrangement of heat insulating grooves in a mold;
FIG. 3 is an explanatory view showing a method of resin-molding a BGA package using a molding die.
FIG. 4 is an explanatory view showing a method of resin-molding a BGA package using a molding die.
FIG. 5 is an explanatory diagram showing a method of resin-molding a BGA package using a mold.
FIG. 6 is an explanatory view showing a method of resin-molding a BGA package using a mold.
FIG. 7 is an explanatory diagram showing an example in which a heat sink is set on a mold.
FIG. 8 is an explanatory diagram showing an example in which a heat sink is set in a mold.
FIG. 9 is an explanatory view showing an example in which a heat sink is set on a mold.
FIG. 10 is a plan view and a side view showing an example of a heat sink.
FIG. 11 is a plan view and a side view showing an example of a heat sink.
FIG. 12 is a plan view and a side view showing an example of a heat sink.
FIG. 13 is a perspective view showing a conventional example of a BGA package, partially cut away.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Semiconductor chip 12 Substrate 14 Heat sink 16 Cavity 18 Pot 24 Lower mold 25 Suction groove 26 Upper mold 28 Suction hole 30, 32, 34 Heat insulation groove 40 Resin tablet 42 Molten resin 44 Molded product runner 46 Mold resin 50 Step 50a Set recess 52 , 54 Resin trap section

Claims (3)

Manufacture of a BGA package in which a substrate is clamped by a lower mold having a set portion for setting the substrate at a predetermined position and an upper mold having a cavity concave portion for sealing a semiconductor chip with a resin, and filling the cavity with a resin and molding the resin. In the mold used for
In the lower mold and / or the upper mold, a heat insulating groove for controlling heat conduction by changing a groove width or a groove depth so as to harden the resin filled in the cavity from a center portion first at a position around the cavity. A mold used for manufacturing a BGA package, wherein the mold is provided. Manufacture of a BGA package in which a substrate is clamped by a lower mold having a set portion for setting the substrate at a predetermined position and an upper mold having a cavity concave portion for sealing a semiconductor chip with a resin, and filling the cavity with a resin and molding the resin. In the mold used for
By changing the groove width or the groove depth near the mold runner and / or the gate, heat conduction to the resin in the mold runner or the gate is suppressed more than to the resin filled in the cavity. A mold used for manufacturing a BGA package, wherein a heat insulating groove for improving resin filling from the gate to the cavity is provided. The inner surface of the cavity concave portion is provided in a concave shape, and at the time of filling the resin, the heat radiating plate disposed in the cavity concave portion is warped to supply the resin excessively, and the heat radiating plate is provided to return to the flat surface by the resin shrink after the resin filling. 3. A mold according to claim 1, wherein said mold is used for manufacturing a BGA package.

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