JP2003170465A - Method for manufacturing semiconductor package and sealing mold therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a semiconductor package without leaking a sealing resin to the lower surface of a circuit board without bringing about a crack even when a ceramic circuit board is adopted when the package is manufactured by resin sealing in a transfer molding process. <P>SOLUTION: The method for manufacturing the semiconductor package comprises the step of fixing the circuit board such as a ceramic circuit board 2 or the like to the inner peripheral side of a frame 8 via an adhesive film 7, the step of mounting a semiconductor chip 3 on the upper surface of the board 2, and the step of clamping the frame 8 in which the board 2 on which the chip 3 is mounted by the upper mold 9b and the lower mold 9a, and the step of casting the sealing resin 11 in the cavity 10 formed at the inside of the frame 8, the resin sealing the chip 3 included in the cavity 10 and the upper part of the board 2. The method further comprises the steps of casting the resin 11 from above the board 2 in the step of resin molding. According to this, since the frame 8 is clamped, the crack is not generated, and intrusion of the resin 11 into the gap between the board 2 and the film 7 can be prevented. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a semiconductor package and a sealing die for the same.

[0002]

2. Description of the Related Art In recent years, with the miniaturization of electronic equipment and the increase of power consumption, semiconductor packages have been mounted on a printed wiring board at a high density.

FIG. 6 shows an example of a small semiconductor package called CSP. In this semiconductor package 1, a semiconductor chip 3 is joined to the upper surface of a wiring board 2 with an adhesive or the like, and electrode pads (not shown) formed on the peripheral portion of the upper surface of the semiconductor chip 3 and the wiring board. 2 is electrically connected to a connection electrode (not shown) formed on the peripheral portion of the upper surface of the semiconductor chip 3, the bonding wire 4 and the upper portion of the wiring board 2 by the resin package 5 (sealed). Resin). An external connection electrode 6 electrically connected to the connection electrode by a contact in a through hole is formed on the lower surface of the wiring board 2. By the external connection electrode 6,
It is adapted to be electrically connected to a printed wiring board (not shown) or the like.

As the wiring board 2 of such a semiconductor package 1, a ceramic wiring board which is capable of high-density wiring and has characteristics such as high thermal conductivity has been widely used. On the other hand, for resin sealing, the semiconductor chip 3 and the wiring substrate 2 are used.
A transfer molding method is widely used, in which and are placed in a cavity of a sealing die, and resin is injected into the cavity. This is because it has advantages such as higher productivity and easier automation than other sealing methods such as the potting resin sealing method and the resin printing sealing method.

Therefore, there is a demand for a method of manufacturing a semiconductor package in which a ceramic wiring board is used and sealing is performed by a transfer molding method.
Since the ceramic wiring board has the property of being hard and brittle, cracks may occur in the usual manufacturing method of directly clamping with a sealing die.

A method for solving this problem is disclosed in, for example, Japanese Patent Laid-Open No.
No. 000-133748. The resin sealing process described in the publication will be described with reference to FIG. The ceramic wiring board 2 is fixed to the frame body 8 via the adhesive film 7 at least at the peripheral portion (may be the entire surface) of the lower surface on which the external connection electrodes 6 are formed. Further, the semiconductor chip 3 is joined to the upper surface of the ceramic wiring board 2, and the electrode pads (not shown) of the semiconductor chip 2 and the connection electrodes (not shown) on the upper surface of the substrate are electrically connected by the bonding wires 4. .

Next, the ceramic wiring board 2 fixed to the frame body 8 is arranged at a predetermined position of the lower die 9a of the sealing die 9, and the frame body 8 is combined with the upper die 9b having a recess. Clamp between. Thereby, the lower mold 9a, the frame body 8, the upper mold 9
Since the semiconductor chip 3, the bonding wire 4, and the upper portion of the ceramic wiring board 2 are enclosed in the cavity 10 formed by b, the molten sealing resin 11 is placed in the cavity 10 in the upper mold 9b and the frame. It is injected from the resin injection port 12 between the bodies 8. When the sealing resin 11 is cured, the finished product is taken out.

According to such a manufacturing method, since the frame body 8 to which the ceramic wiring board 2 is fixed is clamped by the sealing die 9, the damage to the ceramic wiring board 2 as described above can be avoided. That is, the manufacturing method of the semiconductor package 1 that uses the ceramic wiring substrate 2 and adopts the transfer molding method can be realized. The ceramic wiring board 2 is fixed to the adhesive film 7 in order to prevent the sealing resin from adhering to the lower surface of the ceramic wiring board 2 forming the external connection electrodes 6.

[0009]

However, in the method of clamping the frame body 8 as described above, resin leakage to the lower surface side of the board is more likely to occur than in the method of directly clamping the ceramic wiring board 2. . This is because the resin injection port 12 is disposed on the side of the ceramic wiring board 2 so that the sealing resin 11 is injected so as to be vertically pressurized on the side surface of the ceramic wiring board 2, and the ceramic wiring is then applied. This is because peeling occurs between the substrate 2 and the adhesive film 7 and the sealing resin 11 enters.

That is, the ceramic wiring board 2 and the adhesive film 7 are adhered by a weak force only by the adhesive force of the adhesive film 7. On the other hand, since the sealing resin 11 flows into the cavity 10 from the side surface direction of the ceramic wiring board 2, a resin injection pressure is applied to the side surface of the ceramic wiring board 2 and a force in a direction for separating the adhesive film 7 from the ceramic wiring board 2. Occurs. When this peeling force becomes larger than the adhesive force between the ceramic wiring board 2 and the adhesive film 7, the adhesive film 7 is peeled from the ceramic wiring board 2, and the sealing resin 11 penetrates into the gap and wraps around to the lower surface side of the substrate. is there.

In such a case, the ceramic wiring board 2
The sealing resin 11 may adhere to the external connection electrodes 6 formed on the lower surface of the semiconductor package 1, and it becomes difficult for the semiconductor package 1 with the resin adhesion to maintain good electrical connection with the wiring board of the electric device.

An object of the present invention is to solve the above problems and to prevent the sealing resin from adhering to the lower surface of the substrate when resin-sealing by a transfer molding method using a ceramic wiring substrate or the like.

[0013]

In order to solve the above-mentioned problems, the invention according to claim 1 is to fix the wiring board to the inner peripheral side of the frame through an adhesive film, and the upper surface of the wiring board. A step of mounting a semiconductor element on the substrate, and a frame body to which the wiring board on which the semiconductor element is mounted is fixed, is clamped by an upper mold and a lower mold, and a sealing resin is formed in a cavity formed inside the frame body. And the step of resin-encapsulating the semiconductor element and the upper part of the wiring board enclosed in the cavity to manufacture a semiconductor package, in the step of resin-sealing, sealing from above the wiring board. It is characterized by injecting a stop resin. With this configuration, the injection pressure of the sealing resin acts in the direction of pushing the wiring board into the adhesive film, so that the sealing resin can be prevented from entering between the adhesive film and the wiring board. Therefore, it is possible to prevent the sealing resin from adhering to the contacts or electrodes on the lower surface of the wiring board.

According to a second aspect of the present invention, in the method of manufacturing a semiconductor package according to the first aspect, the wiring board is a ceramic wiring board, and the frame is clamped by a sealing die. Because of the configuration, it is possible to use a ceramic wiring board using a ceramic material that easily causes cracks, and thus realize high-density wiring.

According to a third aspect of the present invention, in the method of manufacturing a semiconductor package according to the first aspect, the adhesive film has a two-layer structure including an adhesive layer and a base material, and the adhesive layer is a wiring. It is characterized in that it is set thicker than the thickness of the electrode formed on the lower surface of the substrate, and the adhesive layer easily follows the uneven shape due to the electrode, so that the adhesion between the wiring substrate and the adhesive film is improved. Can be kept.

According to a fourth aspect of the present invention, in the method of manufacturing a semiconductor package according to the first aspect, the injection of the sealing resin is performed from above the central portion of the wiring board excluding the outer peripheral edge portion 10%. Is characterized by. In general, when the sealing resin is injected from above the outer peripheral edge, the extension part of the resin injection path is close to the outer peripheral edge of the wiring board, so that the adhesive film outside this outer peripheral edge has a highly fluid sealing. A force in the peeling direction acts from the resin, and the sealing resin may penetrate between the wiring board and the adhesive film. Such a phenomenon can be prevented above the central portion of the wiring board except the outer peripheral edge portion 10%. Here, the outer peripheral edge portion 10% means a region having a constant width from the outer peripheral edge and occupying 10% of the total area of the upper surface of the wiring board.

According to a fifth aspect of the present invention, in the method of manufacturing a semiconductor package according to the third aspect, the base material of the adhesive film is made of a polyimide resin, and the polyimide resin is deformed even in a high temperature environment. Therefore, it is difficult to keep the adhesion between the adhesive film and the ceramic wiring board when fixing the semiconductor element to the ceramic wiring board, joining the bonding wire to the ceramic wiring board and the semiconductor element, and sealing with resin. It is possible to prevent the formation of gaps.

According to a sixth aspect of the present invention, there is provided a sealing die used in a resin sealing process for manufacturing a semiconductor package, wherein a wiring board is fixed to an inner peripheral side through an adhesive film. The upper mold includes a lower mold and an upper mold for clamping. The upper mold has a recess for forming a cavity for enclosing the wiring board and a semiconductor element mounted on the upper surface thereof inside a frame, and the lower mold. It has a resin injection port opened above the substrate installation region set above.

According to a seventh aspect of the present invention, in the sealing die according to the sixth aspect, the resin injection port of the upper die excludes the outer peripheral edge portion 10% of the substrate installation area set on the lower die. It is characterized by opening above the central part.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A method of manufacturing a semiconductor package according to an embodiment of the present invention will be described with reference to the drawings. Since the semiconductor package as a finished product is the same as the conventional one described with reference to FIG. 6, detailed description thereof will be omitted with reference to FIG.

As shown in FIG. 1, the ceramic wiring substrate 2 having the land-shaped external connection electrodes 6 formed on the lower surface is fixed to the frame body 8 via the adhesive film 7 at least at the peripheral portion of the lower surface. At this time, the ceramic wiring board 2 and the adhesive film 7 are fixed so that no gap is formed between them.

For this purpose, as shown in FIG. 2, the adhesive film 7 has a two-layer structure composed of an adhesive layer 7a and a base material 7b, and the adhesive layer 7a is made of a metal such as tungsten. The thickness of the external connection electrode 6 (thickness of several microns to several tens of microns) is set so as to be able to follow the uneven shape, and is preferably thicker than the thickness of the external connection electrode 6. Base material 7
For b, a material such as a polyimide resin that is unlikely to change in temperature is used. The adhesive layer 7a is made of acrylic resin, thermoplastic polyimide resin, or the like.

Next, the semiconductor chip 3 is bonded to the upper surface of the ceramic wiring board 2 with an adhesive or the like, and the electrode pads (not shown) of the semiconductor chip 3 and the ceramic wiring board 2 are bonded.
The upper connection electrode (not shown) is electrically connected by the bonding wire 4.

Next, as shown in FIG. 3, the ceramic wiring board 2 fixed to the frame body 8 is placed at a predetermined position of the lower mold 7a, and the frame body 8 is clamped between the upper mold 7b and the frame body 8. Then, the cavity 10 composed of the lower mold 7a, the frame body 8 and the upper mold 7b.
The semiconductor chip 3, the bonding wires 4, and the upper part of the ceramic wiring board 2 are included therein.

For this purpose, the lower die 7a positions the adhesive film 7, the ceramic wiring board 2, and the frame body 8 such as the concave work holding portion 9c at a predetermined installation position, and the upper portion of the ceramic wiring board 2 is positioned. A structure having a structure capable of exposing a desired height is used. The upper die 9b includes the semiconductor chip 3 and
A recess 9d having a width dimension and a height dimension that form a cavity 104 capable of containing the bonding wire 4 and the upper portion of the ceramic wiring substrate 2, and a center of the recess portion corresponding to above the substrate installation position of the lower mold 9a. A resin injection port 12 that is opened in the section is used. Although illustration is omitted, the upper mold 9b is connected to the resin injection port 12, and a pot for heating and melting a sealing resin such as a solid thermosetting resin to be charged therein, and a pot melted in the pot. A push-up jig called a plunger for pushing up the sealing resin is provided, and an exhaust hole for exhausting the air in the cavity is provided in one of the upper die 9b and the lower die 9a.

Then, as described above, the frame body 8 is attached to the lower mold 9.
In the state of being clamped by a and the upper mold 9b, the solid sealing resin put into the pot is heated and melted, and the plunger is pushed up to push the molten sealing resin 11 into the cavity 10 through the resin injection port 12. Press into and fill up.

When the sealing resin in the cavity 4 is cured,
The upper mold 9b and the lower mold 9a are opened, and the adhesive layer 9a and the frame 8 are peeled off to take out the semiconductor package 1 including the resin package 5, the semiconductor chip 3, the bonding wires 4, and the ceramic wiring board 2.

According to this method, since the ceramic wiring board 2 is not directly clamped by the sealing mold 9, the ceramic wiring board 2 is not damaged by the clamp.

Further, since the sealing resin 11 is press-fitted from above through the resin injection port 12 during resin sealing, the sealing resin 11 applies downward pressure to the upper surface of the ceramic wiring board 2, that is, , The ceramic wiring board 2 will be pressed by the adhesive film 7,
At this time, the adhesive force between the ceramic wiring board 2 and the adhesive film 7 is the sum of the adhesive force of the adhesive film 7 and the resin injection pressure. Therefore, the adhesive film 7 is less likely to be peeled off from the ceramic wiring substrate 2, the sealing resin 11 is less likely to enter between the ceramic wiring substrate 2 and the adhesive film 7, and the adhesion of the sealing resin 11 to the lower surface of the substrate is prevented. To be done. At this time, the closer the resin injection port 12 is to the axis passing through the center point of the ceramic wiring substrate 2, the higher the effect of suppressing the intrusion of the sealing resin 11 into the lower surface 9 of the substrate.
Particularly, if the resin injection port 12 is provided above the central area excluding the outer edge area of 10% of the substrate plane size, it is possible to effectively prevent the sealing resin 11 from entering the lower surface of the substrate.

Furthermore, since a material such as polyimide, which does not easily change in temperature, is used for the base material 7b of the adhesive film 7, when the semiconductor chip 3 is fixed to the ceramic wiring board 2, the ceramic wiring board 2 and the semiconductor chip 3 At the time of bonding the bonding wire 4 to and the resin sealing, even if the composite body including the ceramic wiring board 2, the adhesive film 7, and the frame body 8 is placed in a high temperature environment of about 120 ° C. to 250 ° C. The film 7 exhibits dimensional stability. Therefore, the adhesive film 7 is not largely deformed, the close contact with the ceramic wiring substrate 2 is maintained, and the generation of the gap is prevented, which also prevents the sealing resin 1 on the lower surface of the substrate.
The adhesion of 1 is prevented.

In the above embodiment, the case where the semiconductor chip 3 is mounted on the ceramic wiring board 2 has been described, but the wiring board is not limited to the ceramic wiring board 2 and is composed of a resin substrate or a metal substrate. The method of the present invention in which the frame 8 is clamped without directly clamping the wiring board is also useful when using the.

Further, in the above-mentioned embodiment, the ceramic wiring substrate 2 on which the semiconductor chip 3 is mounted and fixed to the frame body 8 is arranged at a predetermined position of the lower mold 9a, but the ceramic is placed on the lower mold 9a. The wiring board 2 and the frame 8 may be fixed and the semiconductor chip 3 may be mounted.

Further, in the above-described embodiment, only the peripheral portion of the lower surface of the ceramic wiring board 2 is fixed to the adhesive film 7, but it is sufficient to fix it at least at the peripheral portion of the lower surface, as shown in FIG. May be fixed.

In the above embodiment, the semiconductor chip 3 is used.
The case of manufacturing the semiconductor package 1 in which only one is mounted on the ceramic wiring board 2 has been described. However, as shown in FIG. 5, a plurality of semiconductor chips 3 are mounted on the ceramic wiring board 2 to manufacture the semiconductor package 1. In some cases, the method of the present invention is useful.

In each of the above-mentioned embodiments, the land-shaped external connection electrodes 6 are formed in a wide area on the lower surface of the ceramic wiring board 2, and the work holding portion for accommodating these external connection electrodes 6 together with the adhesive film 7 is provided. 9c is the lower mold 9
Although the example formed in a is illustrated, the ceramic wiring substrate 2
When the external connection electrode 6 is formed only on the peripheral portion of the lower surface of the and the adhesive film 7 into which the external connection electrode 6 enters is used, or when the ball-shaped external connection electrode 6 is provided after resin sealing, The work holding portion 9c may be sized to accommodate only the adhesive film 7. The shape of the cavity 10 can also be appropriately changed according to the desired shape of the resin package 5.

[0036]

As described above, according to the present invention, the wiring board on which the semiconductor element is mounted is adhered to the frame body through the adhesive film, and the wiring board of the wiring board is clamped with the sealing die. Since the resin is injected from above, it is possible to prevent the sealing resin from penetrating between the wiring board and the adhesive film, and to prevent the sealing resin from adhering to the lower surface of the wiring board, that is, the electrode formation surface. A semiconductor package is obtained.

[Brief description of drawings]

FIG. 1 is a method for manufacturing a semiconductor package according to a first embodiment of the present invention, showing a state in which a wiring board on which one semiconductor element is mounted is fixed to a frame body with an adhesive film at a peripheral portion of a lower surface. Sectional view

FIG. 2 is an enlarged cross-sectional view of the adhesive film portion shown in FIG.

FIG. 3 is a cross-sectional view showing a step of placing the semiconductor element, the wiring board, the adhesive film, and the frame body shown in FIG. 1 in a sealing die and resin-sealing them.

FIG. 4 is a method of manufacturing a semiconductor package according to a second embodiment of the present invention, which includes a step of resin-sealing a wiring board on which one semiconductor element is mounted, with the entire lower surface adhered to an adhesive film. Cross section

FIG. 5 is a method of manufacturing a semiconductor package according to a third embodiment of the present invention, which is a step of resin-sealing a wiring board on which two semiconductor elements are mounted while being adhered to an adhesive film at a peripheral portion of a lower surface. Cross section of

FIG. 6 is a sectional view of a conventional semiconductor package.

FIG. 7 is a cross-sectional view of a resin sealing step in a conventional semiconductor package manufacturing method.

[Explanation of symbols]

1 Semiconductor package 2 Ceramic wiring board 3 semiconductor chips 6 External connection electrode 7 Adhesive film 7a adhesive layer 7b substrate 8 frame 9 Sealing mold 9a Lower mold 9b Upper mold 10 cavities 11 Sealing resin 12 Resin injection port

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 4F202 AD04 AD18 AD23 AD27 AH37                       CA11 CA12 CB01 CB12 CB17                       CK06 CQ01 CQ05                 4F206 AD04 AD18 AD23 AD27 AH37                       JA02 JA07 JB12 JB17 JF05                       JF35 JL02 JM04 JN21 JQ81                 5F061 AA01 BA03 CA21 DA07

Claims (7)

[Claims] 1. A step of fixing a wiring board to an inner peripheral side of a frame body with an adhesive film, a step of mounting a semiconductor element on an upper surface of the wiring board, and a wiring board on which the semiconductor element is mounted is fixed. The frame body is clamped by an upper die and a lower die, and a sealing resin is injected into a cavity formed inside the frame body, and a semiconductor element and a wiring board upper part encapsulated in the cavity are filled with resin. A method of manufacturing a semiconductor package, wherein, when a semiconductor package is manufactured by performing a sealing step, a sealing resin is injected from above the wiring board in the resin sealing step. 2. The method of manufacturing a semiconductor package according to claim 1, wherein the wiring board is a ceramic wiring board. 3. The adhesive film has a two-layer structure consisting of an adhesive layer and a base material, and the adhesive layer is set to be thicker than the thickness of the electrode formed on the lower surface of the wiring board. The method for manufacturing a semiconductor package according to claim 1. 4. The method for manufacturing a semiconductor package according to claim 1, wherein the injection of the sealing resin is performed from above the central portion of the wiring board except for the outer peripheral edge portion 10%. 5. The method of manufacturing a semiconductor package according to claim 3, wherein the base material of the adhesive film is made of a polyimide resin. 6. An encapsulating mold used in a resin encapsulating process for manufacturing a semiconductor package, wherein the wiring substrate is an upper mold for clamping a frame body fixed to an inner peripheral side through an adhesive film. A lower mold, wherein the upper mold is a recess formed in the frame body to form a cavity for enclosing the wiring board and a semiconductor element mounted on the upper surface thereof, and a substrate set on the lower mold. A sealing mold having a resin injection port opened above the installation region. 7. The resin injection port of the upper mold is opened above the central portion of the substrate installation region set on the lower mold except for 10% of the outer peripheral edge portion. Sealing mold.