JP3479121B2 - Resin molding method for BGA package - Google Patents

Description

Detailed Description of the Invention

[0001]

The present invention relates to a resin for BGA package .
Regarding the molding method .

[0002]

2. Description of the Related Art FIG. 13 shows the configuration of a conventional BGA package. As shown in the figure, the BGA package is formed by mounting the semiconductor chip 6 on the upper surface of the substrate 5 and molding the resin on one side. When manufacturing such a BGA package, usually, the semiconductor chip 6 is mounted on the substrate 5, one surface of the substrate 5 is resin-molded, and then the solder balls 7 are bonded to the lower surface of the substrate 5 to obtain a product.

[0003]

By the way, the conventional BG
The problem is that the A package is inferior in heat dissipation to QFP and the like. This is because a package using a metal lead frame such as QFP can dissipate heat from the lead frame portion, whereas a BGA package has low heat dissipation from the substrate because the substrate is an insulator. . Further, in the case of a BGA package, the area occupied by the mounted semiconductor chip is large relative to the package size, heat dissipation commensurate with the amount of heat generated by the semiconductor chip cannot be obtained, and the BGA package is resin-molded on only one side of the substrate. This is because the surface area of the resin mold portion is reduced to about 25% or less as compared with QFP, and heat radiation is limited.

Another problem is that the BGA package is resin-molded on only one side of the substrate 5 as shown in FIG. The problem is that the substrate warps when it is done. The present invention has been made in order to solve these problems, and the conventional BG
Along with solving the problem of heat dissipation in A package, B
An object of the present invention is to provide a product capable of suitably preventing the warpage of a GA package, and to provide a molding die capable of suitably manufacturing these products.

[0005]

The present invention has the following constitution in order to achieve the above object. That is, the semiconductor chip
A lower die that sets the mounted board and a semiconductor chip
An upper mold provided with a cavity recess for oil sealing
Using a molding die, leave it on the inner surface of the cavity recess.
Place the hot plate and clamp the substrate with the lower and upper molds.
By filling a resin into Activity, one surface of the substrate on which the semiconductor chip is mounting tower <br/> is resin-molded, to expose the outer surface to the outer surface facing the substrate of the molding resin heat sink resin integrally BGA obtain a shaped B GA package
In the resin molding method of a package, the cavitation
The inner surface of the recess where the heat sink is placed is formed in a concave shape.
The upper die is used, and the semiconductor chip is mounted on the lower die.
Set the substrate and place it in front of the cavity recess of the upper mold.
The heat dissipation plate is adsorbed and supported on the concave surface facing the substrate,
Clamp the substrate with the lower mold and the upper mold to
The heat sink to the cavities.
B. Make sure that the warp shape matches the shape of the inner surface of the recess.
After the cavity is filled with resin, the resin after resin filling is cured
The heat sink returns to a flat surface due to shrinking when reacting
It is characterized by resin molding. Further, the concave surface of the cavity recess, is communicated to a vacuum suction mechanism, before the heat dissipation plate
It is characterized in that an upper mold having a suction hole for suction-supporting the concave surface is used . Also, the lower mold and / or the upper mold
Of the periphery of the cavity, the heat from the peripheral portion of the package
A mold that has a heat insulating groove that suppresses conduction
It is characterized by being used . Inside the cavity
The resin filled in the cavity can be cured first from the center of the cavity . In the vicinity of the mold runners and / or gates, molding die provided with a thermal insulation grooves to inhibit than the thermal conductivity to the resin mold runner or the gate to the resin filled in the cavitation I
Is used . This allows the mold runner
Resin from the gate and / or gate to the cavity
It is possible to improve the sex.

[0006]

Function : Resin mold of BGA package according to the present invention
The method is to integrally mold the substrate and heat sink with resin.
The above makes it possible to obtain a BGA package having excellent heat dissipation. Release when resin molding
The inner surface of the cavity recess where the heat plate is placed is formed into a concave surface.
The upper surface of the cavity is
The warp shape matches the shape of the
To make the amount of resin shrinkage due to the curing reaction equal
Therefore, after the resin cures, the resin should be
Can be molded. This makes it possible to effectively prevent deformation such as warpage of the package . Further , the resin is hardened first from the central portion of the cavity by heat conduction from the heat dissipation plate, so that deformation can be prevented and a highly reliable product can be manufactured.

[0007]

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. The BGA package according to the present invention is characterized in that a heat dissipation plate is integrally resin-molded at the same time when one surface of the substrate is resin-sealed. FIG. 1 is an explanatory view showing the structure of a molding die used for manufacturing the BGA package according to the present invention. The figure shows a state in which the substrate 12 on which the semiconductor chip 10 is mounted is set together with the heat sink 14 in the cavity 16 of the molding die. In the figure, 18 is a pot, 20 is a plunger, and 22 is a mold runner and a gate that connect the pot 18 and the cavity 16.

The lower die 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 die 26 and the lower die 24 which are provided with cavity recesses for resin-sealing the semiconductor chip 10. The resin is molded by filling the cavity 16 with resin. The lower mold 24 is provided with a suction groove 25 for supporting the substrate 12 by suction. The suction groove 25 communicates with the vacuum suction mechanism. In addition, a suction hole 28 is provided in the cavity concave portion of the upper mold 26 at approximately the center of the concave surface.
8 is connected to a vacuum suction mechanism so that the heat dissipation plate 14 can be adsorbed to the inner surface of the cavity recess.

In this embodiment, as shown in FIG. 1, the inner surface of the cavity recess provided in the upper mold 26 is formed in a concave shape with a bulged central portion. When the cavity 16 is viewed in the thickness direction, the central portion is made thicker and the periphery is made thinner in order to minimize warpage of the substrate 12 caused by the resin shrinkage at the time of resin molding.

Further, the lower mold 24 and the upper mold 26 have 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 for suppressing heat conduction around the gate portion. 34 is provided. FIG. 2 shows a planar arrangement of these heat insulating grooves 30 and 32. These heat insulation grooves 30,
The purpose of 32 and 34 is to provide a void in the mold so as to suppress heat conduction acting on the molten resin at the time of filling the resin and suppress hardening of the thermosetting resin to enable suitable resin molding. And

3 to 6 show B using the above mold.
It shows how a GA package is resin-molded. FIG. 3 shows a state in which the substrate 12 is set in the lower mold 24 and the heat sink 14 is set in the upper mold 26 in a state where the mold die is 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 in the cavity recess inner surface of the upper mold 26 by the suction hole 28. A resin tablet 40 is put into the pot 18.

Next, the substrate 12 is clamped by the lower mold 24 and the upper mold 26, and the molten resin is pumped into the cavity by the plunger 20. Figure 4 shows the plunger 20 with molten resin 4
2 shows a state in which the cavity is filled with resin. In the molding die of the embodiment, since the resin is hardened first from the center of the cavity, a protrusion is provided on the inner surface of the heat dissipation plate 14 to reduce the distance between the surface of the semiconductor chip 10 and the heat dissipation plate 14, and the resin capacity between them is reduced. The resin is made small and heat is easily conducted from the heat dissipation plate 14 so as to accelerate the resin curing. As a result, the hardening of the resin proceeds from the center of the package, and the influence of the resin shrink can be suppressed.

The heat insulating grooves 30, 32, and 34 act to suppress heat conduction in the mold runner portion, the package peripheral portion, and the gate portion, so that the resin hardening in the mold runner and the package peripheral portion is delayed. To The heat conduction by the heat insulating groove can be appropriately controlled by changing the groove width and the groove depth. For example, when the depth of the heat insulating groove is shallower than that in the case where the depth is deep, the heat conduction becomes better, so that the resin hardening can be accelerated. The heat insulating groove 32 provided in the peripheral portion of the package is intended to accelerate the resin curing from the central portion of the package and suppress the action of the resin shrink.

In the vicinity of the gate, adiabatic grooves 34 are provided in the upper, lower, left and right sides of the gate to suppress heat conduction and delay hardening at the gate. This allows the resin to be pressure-fed by the plunger 20 even after the filling of the resin in the cavity is almost completed and the hardening of the resin in the cavity has started, so that good resin molding can be performed. This is because FIG. 5 shows a state in which resin filling into the cavity is almost completed and resin molding is performed while applying resin pressure by the plunger 20.

Although a heater for heating the die is installed in the die, the heater provided near the pot or the die runner is energized to 100% when the resin tablet 40 is charged. 40 is quickly melted, and after the resin tablet 40 is melted, current is suppressed to suppress resin hardening in the mold runner or gate portion, and after the resin is completely filled in the cavity and the gate is closed, It is also effective to re-energize again and control so as to accelerate the resin curing.

As described above, in the embodiment, the inner surface of the cavity concave portion of the upper die 26 has a concave shape. Therefore, when the resin is filled, the heat dissipation plate 14 is warped upward due to the resin pressure (FIG. 4). As shown in FIG. 5, the resin shrinks back to a flat surface when it is cured. As described above, in the method of filling the heat sink 14 with the warped shape and filling the resin, the amount of the excessively supplied resin is made equal to the amount of the resin shrink due to the curing reaction of the resin, so that the heat sink 14 after the resin molding is performed.
Can be made a flat surface, and it becomes possible to prevent warping of the package.

After the resin is molded, 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 with the molding resin 46 and the outer surface of the heat dissipation plate 14 is exposed on the outer surface of the molding resin 46. In this molded product, the heat dissipation plate 14 is integrally resin-molded with the molding resin 46, so that the heat dissipation performance of the package can be effectively improved by the heat dissipation effect of the heat dissipation plate 14. Further, since the heat dissipation plate 14 is integrally molded, the heat dissipation plate 14 can prevent deformation such as warpage of the package, and the flatness of the substrate 12 can be obtained.

In the molding die of this embodiment, since the heat dissipation plate 14 is integrally formed with the substrate 12, the heat dissipation plate 14 is set in the cavity of the molding die and resin-molded. Therefore, in the above-described embodiment, the heat dissipation plate 14 is vacuum-sucked on the inner surface of the cavity and resin-molded. However, when the heat dissipation plate 14 is set in the cavity and resin-molded, the heat dissipation plate 14 is used.
There may be a problem that a thin flash of resin occurs on the outer surface of the. 7 to 9 show a structural example of a metal mold for resin-molding so that resin burrs do not occur.

FIG. 7 (b) is a state in which the heat dissipation plate 14 is vacuum suction-supported on the inner surface of the cavity recess, and FIG. 7 (a) is a partially enlarged view thereof. This mold has a heat sink 1 on the inner surface of the cavity recess.
4 is an example in which the resin trap portion 52 is configured by providing a step 50 at a portion abutting the vicinity of the peripheral edge of 4 and providing a gap between the outer surface of the peripheral edge of the heat dissipation plate 14 and the inner surface of the cavity recess. The resin trap portion 52 allows the molten resin to slightly enter the outer surface of the heat dissipation plate 14 when the resin is filled.
Heat sink 1 more by hardening the resin in the part
The occurrence of light flash is prevented by preventing the resin from getting into the upper part of 4. The void portion of the resin trap portion 52 is 0 to 0.2 mm, preferably about 0.05 to 0.2 mm. Reference numeral 28a is a suction groove for vacuum suction supporting the heat dissipation plate 14.

FIG. 8 shows a heat sink 14 on the inner surface of the cavity recess.
A set recess 50a for setting the
The resin trap portion 5 is provided between the wall surface of a and the side surface of the heat dissipation plate 14.
4 is an example in which a space is provided and resin molding is performed. In this example, it is prevented that the resin filled in the resin trap portion 54 is cured during resin molding and the resin is prevented from flowing around the outer surface of the heat dissipation plate 14. The resin trap portion 54 has a V-shaped cross section and is provided with a draft taper angle.

The embodiment shown in FIG. 9 is an embodiment in which the heat dissipation plate 14 is exposed on 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 dissipation plate 14 is arranged on the inner surface of the cavity recess are made to be substantially the same as those of the heat dissipation plate 14, and a slight gap is formed between the side surface of the heat dissipation plate 14 and the side surface of the cavity recess. Mold with resin. In the case of this embodiment, this void acts as a resin trap,
The resin can be molded by preventing the resin from flowing to the outer surface of the heat dissipation plate 14. Further, FIG. 9A shows an example of resin molding in which the fracture surface side of the heat dissipation plate 14 formed by press punching is made the exposed surface side. In this way, when the resin is molded with the fracture surface side being the outside, the fracture surface portion is formed in an inverse taper shape, so that there is an advantage that the heat dissipation plate 14 is less likely to be separated from the molding resin.

In the molding die of each of the above embodiments, the upper die 26
It is characterized in that the heat dissipation plate 14 is arranged in the cavity concave portion provided in the resin mold, and in this case, in order to cure the resin first from the center of the cavity, the semiconductor chip 10 and the heat dissipation plate 14 are combined. The space was narrowed to reduce the resin capacity, and heat conduction was further promoted in the central portion. 10, 11 and 12 show examples of the heat dissipation plate 14 which can be preferably used in the BGA package with the heat dissipation plate.

The heat sink 14 shown in FIG. 10 is a semiconductor chip 1.
This is an example in which a stepped protrusion 14a is provided at the center of the inner surface facing 0. As shown in FIG. 1, since the semiconductor chip 10 is bonded to the substrate 12 at its outer edge portion, the protrusion 14a is provided in a flat shape inside so as not to interfere with the bonding wire. The heat dissipation plate 14 shown in FIG. 11 is an example in which the protrusion 14a is provided so as to project in a mountain shape, and the heat dissipation plate 14 shown in FIG.
In the embodiment shown in FIG. 0, the groove is provided in the diagonal direction of the protrusion 14a. According to the heat dissipation plate 14 shown in FIGS. 11 and 12, there is an advantage that the resin can be easily injected into the gap portion between the semiconductor chip 10 and the heat dissipation plate 14 during the resin molding, and air can be easily removed.

The protrusion 14a provided on the heat dissipation plate 14 is for reducing the resin capacity sandwiched between the semiconductor chip 10 and the resin, thereby promoting resin curing.
Of course, the design of 4a is not limited to the above example. For example, a method of providing a large number of small protrusions or a method of providing a plurality of linear protrusions is possible. It should be noted that these heat dissipation plates 14 can be easily manufactured by press punching and are also useful in that they do not require manufacturing cost.

[0025]

EFFECT OF THE INVENTION The resin module of the BGA package according to the present invention.
According to the yield method , as described above, the BGA package is obtained by integrally molding the substrate and the heat sink with resin.
It can, in this to improve the heat dissipation of the package
It can be provided as a product having more excellent heat dissipation. Further, to prevent warpage of the package, reliable B
The GA package exhibits remarkable effects such as can be and reliably manufactured easily.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a configuration of an embodiment of a molding die.

FIG. 2 is an explanatory diagram showing an arrangement example of heat insulating grooves of a molding die.

FIG. 3 is an explanatory view showing a method of resin-molding a BGA package with a molding die.

FIG. 4 is an explanatory view showing a method of resin-molding a BGA package with a molding die.

FIG. 5 is an explanatory diagram showing a method of resin-molding a BGA package with a molding die.

FIG. 6 is an explanatory diagram showing a method of resin-molding a BGA package with a molding die.

FIG. 7 is an explanatory diagram showing an example of setting a heat dissipation plate on a molding die.

FIG. 8 is an explanatory diagram showing an example of setting a heat dissipation plate on a molding die.

FIG. 9 is an explanatory diagram showing an example of setting a heat dissipation plate on a molding die.

FIG. 10 is a plan view and a side view showing an example of a heat dissipation plate.

FIG. 11 is a plan view and a side view showing an example of a heat dissipation plate.

FIG. 12 is a plan view and a side view showing an example of a heat dissipation plate.

FIG. 13 is a partially cutaway perspective view showing a conventional example of a BGA package.

[Explanation of symbols]

10 semiconductor chips 12 substrates 14 Heat sink 14a protrusion 16 cavities 24 Lower mold 25 suction groove 26 Upper mold 28 Adsorption hole 28a suction groove 30, 32, 34 Insulation groove 40 resin tablets 42 Molten resin 46 Mold resin 50 steps 52, 54 Resin trap section

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Claims (4)

(57) [Claims] 1. A substrate on which a semiconductor chip is mounted is set.
Lower mold and cavity recess that seals the semiconductor chip with resin
Using a mold die with an upper mold provided with a section,
A heat sink is placed on the inner surface of the cavity recess,
Clamp the substrate with the mold and fill the cavity with resin
By, one side of the substrate on which the semiconductor chip is mounted is tree <br/> butter mold, the heat radiating plate on the outer surface to expose the outer surface facing the substrate of the molding resin is molded integrally
Resin molding of the BGA package to obtain a B GA Package
In the above method, the inner surface of the cavity recess where the heat dissipation plate is disposed is a concave surface.
Using the upper mold formed in a shape, set the substrate on which the semiconductor chip is mounted on the lower mold,
A recess facing the substrate in the cavity recess of the upper mold
The heat dissipation plate is adsorbed and supported on the surface , the substrate is clamped by the lower mold and the upper mold, and the molten resin is sealed.
The heat dissipation plate causes the heat dissipation plate to
A warp shape that matches the shape of the inner surface of the recess
After the cavity is filled with resin, the shrinkage caused by the curing reaction of the resin after resin filling
Characterized by resin molding so that the heat sink returns to a flat surface
Resin molding method for BGA package. 2. A vacuum suction mechanism is provided on the concave surface of the cavity concave portion.
And the suction holes that support the heat sink by suction on the concave surface.
The resin molding method for a BGA package according to claim 1, wherein the upper mold provided is used . 3. The lower and / or upper mold cavitates.
Heat conduction from the periphery of the package is suppressed around the
Resin BGA package according to claim 1, wherein the this <br/> to use mold provided with thermal insulation grooves
Molding method. 4. A mold runner and / or a gate are close to each other.
By the side, heat to the resin in the mold runner or gate
Suppresses conduction more than for resin filled cavity
2. A resin mold for a BGA package according to claim 1, wherein a molding die having a heat insulating groove is used.
Method.