JP2003060124A - Heat dissipation type BGA package and method of manufacturing the same - Google Patents

Abstract

(57) [Problem] To provide a heat dissipation type that can easily join a heat sink and a plastic circuit board with a fastening member to increase the joining strength, and at the same time, suppress moisture adsorption on the joining surface and do not impair the hermetic reliability of the semiconductor chip. Provided is a BGA package and a method of manufacturing the same. SOLUTION: In a heat dissipating BGA package 10 in which a metal heat dissipating plate 13 is joined to one surface of a plastic circuit board 11 having a cutout space 12 in the center, an adhesive resin is provided between the plastic circuit board 11 and the heat dissipating plate 13. One or a plurality of through-holes 17 having a layer 15 and perforating the laminate 16 of the plastic circuit board 11 and the heat sink 13
And a fastening member 18 for fastening and joining the stacked body 16.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat dissipation type BGA package having a heat dissipation plate on one side of a plastic circuit board and having a cavity in the center, and a method for manufacturing the same.

[0002]

2. Description of the Related Art With the recent high integration of semiconductor chips,
Demands for high density, high speed, and multi-terminals for semiconductor packages are increasing more and more.
There are many demands for A (ball grid array) type packages. This BGA package is a surface mount type package in which connection terminals made up of many solder balls are arranged on the lower surface. Further, as for this BGA package, a cavity-down heat dissipation type BGA package in which a heat dissipation plate is adhered to a plastic circuit board has been developed in order to deal with the problem of increase in heat generation amount of a semiconductor chip due to recent high performance. .

As shown in FIG. 4, a conventional heat dissipation type BGA
The package 50 is formed by bonding a heat dissipation plate 53 made of copper, copper alloy, or the like to a plastic circuit board 51 having a cutout space 52 in the center through heating, pressurizing, and bonding via a bonding material 54 such as prepreg or adhesive. , The cavity 55 is formed. Also, although not shown, there is one in which a copper plate having a size substantially equal to that of the plastic circuit board in plan view is further provided between the plastic circuit board and the heat dissipation plate to adjust the depth of the cavity. Then, as shown in FIG. 5, in the heat dissipation type BGA package 50, the semiconductor chip 56 is die-bonded to the cavity 55, and the semiconductor chip 56 and the plastic circuit board 51 are wire-bonded with a bonding wire 57 to seal the semiconductor chip 56. Seal with resin 58, and solder balls 59 on the surface of the plastic circuit board 51.
Attached to be used as the semiconductor device 60.

However, in the conventional heat dissipation type BGA package, a joining material such as a semi-cured sheet-like prepreg is brought into contact with a plastic circuit board having irregularities on the surface to join, so that the joining material portion is joined. Adhesive strength may be reduced due to the trapped voids and variations in the thickness of the bonding material. Therefore, a heat dissipation type BGA package is being manufactured by mechanically joining a space between the plastic circuit board and the heat dissipation plate using a fastening member such as a caulking member, a rivet or a screw (including a nut). .

[0005]

However, the conventional heat dissipation type BGA package and the manufacturing method thereof as described above still have the following problems to be solved. (1) In the mode in which the plastic circuit board and the heat sink are mechanically joined using a tightening member, the joining strength is improved, but a gap is created in the joint surface between the plastic circuit board and the heat sink, and this gap is generated. Moisture is absorbed in the. Even if the semiconductor chip mounted in the cavity is protected from the upper surface by a sealing resin such as potting resin or molding resin and protected, the thickness of the sealing resin covering the semiconductor chip depends on the plastic circuit board and the heat sink. Since it is the thinnest per joint surface, it is easily affected by moisture from the joint surface, reducing the hermetic reliability when exposed to a harsh environment. (2) The sealing resin for hermetically sealing the semiconductor chip mounted in the cavity flows into the gap between the joint surfaces of the plastic circuit board and the heat sink, reducing the overall resin thickness and reducing the hermetic reliability. ing. (3) There are variations in the punching positions of the through holes for inserting the fastening members, which are formed by punching in the plastic circuit board and the heat dissipation plate, respectively, which makes it difficult to insert the fastening members. (4) In the mode in which the plastic circuit board and the heat dissipation plate are mechanically joined using a tightening member, the unevenness of the surface of the plastic circuit board causes a warp in the plastic circuit board at the time of joining, so that the solder ball coplanarity Aggravate.

The present invention has been made in view of the above circumstances, and the heat dissipation plate and the plastic circuit board can be easily joined by the tightening member to enhance the joining strength, and at the same time, moisture adsorption on the joining surface can be suppressed. It is an object of the present invention to provide a heat-dissipating BGA package that does not impair the airtight reliability of a semiconductor chip and a manufacturing method thereof.

[0007]

A heat-dissipating BGA package according to the present invention which meets the above-mentioned object is a heat-dissipating BGA package in which a metal heat-dissipating plate is joined to one surface of a plastic circuit board having a notched space in the center thereof. In, there is an adhesive resin layer between the plastic circuit board and the heat dissipation plate, and the plastic circuit board and the heat dissipation plate are inserted into one or a plurality of through holes that are formed by communicating the laminate, and the laminate is tightened and joined. It has a member. As a result, the plastic circuit board and the heat sink are mechanically bonded to improve the bonding strength, and the adhesive resin layer does not adsorb moisture on the bonding surface of the plastic circuit board and the heat sink, so the airtight reliability of the semiconductor chip is improved. Can be increased. Also,
It is possible to prevent the sealing resin for hermetically sealing the semiconductor chip from flowing into the joint surface between the plastic circuit board and the heat dissipation plate, and prevent the reliability of the semiconductor chip from being hermetically sealed. Further, since the through hole into which the tightening member is inserted communicates and pierces the laminated body in which the plastic circuit board and the heat sink are temporarily joined with the adhesive resin, the tightening member can be surely inserted. Further, the adhesive resin layer suppresses warpage during joining of the plastic circuit boards, and can maintain the normal coplanarity of the solder balls.

A heat radiation type BGA according to the present invention which meets the above-mentioned object
The method of manufacturing the package is the method of manufacturing a heat dissipation type BGA package in which a metal heat dissipation plate is joined to one surface of a plastic circuit board having a cutout space in the center, and an adhesive resin layer is provided between the plastic circuit board and the heat dissipation plate. A step of forming a laminated body in a temporarily joined state by stacking via a step, a step of forming one or a plurality of through holes in the laminated body, a tightening member inserted into the through hole and tightened, and a plastic circuit board and a heat dissipation plate And a step of joining. This prevents the adsorption of moisture between the plastic circuit board and the heat sink with the adhesive resin layer, and also prevents the sealing resin for hermetically sealing the semiconductor chip from flowing into the joint surface between the plastic circuit board and the heat sink. Since this can be prevented, a heat dissipation type BGA package can be obtained in which the airtight reliability of the semiconductor chip is prevented from decreasing. Further, since the through hole into which the tightening member is inserted is formed in the laminated body in which the plastic circuit board and the heat radiating plate are superposed and temporarily joined, the tightening member can be easily inserted into the through hole.

In the method of manufacturing the heat dissipation type BGA package according to the present invention, it is preferable that the adhesive resin layer is formed in a semi-cured state by applying a thermosetting adhesive resin on the bonding surface and heating. This makes it possible to bond the plastic circuit board and heat sink with a semi-cured adhesive resin.
Temporary bonding is easy, and the plastic circuit board and the heat sink can be bonded without causing positional displacement. Further, since the through hole is formed in the laminated body, the plastic circuit board and the heat dissipation plate can be accurately joined by the tightening member without causing positional displacement.

Further, in the method for manufacturing a heat dissipation type BGA package according to the present invention, the adhesive resin layer has a non-hygroscopic adhesive sheet having substantially the same size as the outer shape of the plastic circuit board attached to the bonding surface. It can also be formed. This allows the plastic circuit board and the heat sink to be bonded together with an adhesive sheet, so temporary bonding is easy, and the plastic circuit board and the heat sink can be bonded without causing positional displacement. Since the through hole can be formed, the plastic circuit board and the heat dissipation plate can be accurately joined by the tightening member without displacement. Further, since the adhesive resin layer is a non-hygroscopic adhesive sheet, it does not need to be heat-cured and can prevent the heat-radiating BGA package from warping due to heating.

Further, in the method of manufacturing a heat dissipation type BGA package according to the present invention, the adhesive resin layer is formed by mounting a thermosetting adhesive resin sheet having substantially the same size as the outer shape of the plastic circuit board. Is good. With this, since the plastic circuit board and the heat sink are bonded together via the adhesive resin sheet, temporary joining is easy, and the plastic circuit board and the heat sink can be joined without causing positional displacement, and further, in the laminated body in this state. Since the through hole can be formed, the plastic circuit board and the heat dissipation plate can be accurately joined by the tightening member without displacement.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Next, referring to the attached drawings, an embodiment in which the present invention is embodied will be described to provide an understanding of the present invention. 1A and 1B are a front sectional view and a plan view of a heat dissipation type BGA package according to an embodiment of the present invention, and FIGS. 2A to 2C are the same heat dissipation type BGA. FIG. 3 is an explanatory diagram of a package manufacturing method, and FIG. 3 is an explanatory diagram of a mounting form of a semiconductor chip on the heat dissipation type BGA package.

As shown in FIGS. 1A and 1B, a heat dissipation type BGA package 10 according to an embodiment of the present invention is
A metal heat dissipation plate 13 is joined to one surface of a plastic circuit board 11 having a cutout space 12 in the center, and a cavity 14 formed by the cutout space 12 and the exposed surface of the heat dissipation plate 13 is provided. The plastic circuit board 11 and the heat dissipation plate 13 have an adhesive resin layer 15 between them, and are further joined by a rivet 18 made of a copper alloy, which is an example of a fastening member. Moreover, the rivet 18 has an adhesive resin layer 15 between them.
The plastic circuit board 11 and the heat sink 13 are joined to the plastic circuit board 11 and the heat sink 13 by inserting them into, for example, four through holes 17 and pressing the upper and lower ends thereof. ing.

Next, referring to FIGS. 2A to 2C, a heat dissipation type BGA package 10 according to an embodiment of the present invention.
The manufacturing method of will be described. As shown in FIG. 2A, for example, a resin having high heat resistance, dielectric properties, insulation properties, and processability such as BT resin (a resin containing bismaleimide triazine as a main component) or epoxy resin is used as a base material. ,Copper foil,
A single-layer or multi-layer plastic circuit board 11 having a circuit pattern of conductor wiring formed by photolithography or etching from copper plating or the like is formed. Further, a notch space 12 for forming a cavity 14 is formed in the center portion of the plastic circuit board 11 by punching or router processing.

On the other hand, the heat dissipation plate 13 is formed of a metal plate having excellent heat dissipation properties, such as a copper plate or a copper alloy plate, and the surface opposite to the surface to be joined to the plastic circuit board 11 is plated with Ni to prevent oxidation. (Oxidation resistance treatment). On the other hand, the surface of the side to be joined to the plastic circuit board 11 is subjected to blackening treatment or the like in order to improve mechanical adhesion when the semiconductor chip 19 (see FIG. 3) is joined to the bottom of the cavity 14 with Ag paste or the like. Surface treatment is recommended.

The adhesive resin layer 15 is provided on one side of the plastic circuit board 11 on the side where the adhesive resin made of epoxy or the like is bonded to the heat dissipation plate 13, or on the plastic circuit board 1.
It is formed by applying it to the heat dissipation plate 13 on the side to be joined with 1 or to both surfaces facing each other by means of screen printing, a roll coater, a brush or the like. Then, the adhesive resin layer 15
Is approximately 100 ° C, although it varies slightly depending on the type of adhesive resin.
And heat for about 15 minutes to form a semi-cured state. Then, the plastic circuit board 11 and the heat dissipation plate 13 are overlapped with each other via the adhesive resin layer 15. Since the adhesive resin layer 15 is in a semi-cured state, the plastic circuit board 11 and the heat dissipation plate 13 can be accurately overlapped with each other by easy handling to form the laminated body 16 in a temporarily joined state, and the through hole 17 can be accurately formed. It can be formed easily and easily. Also, the adhesive resin layer 1
5 is made of a liquid resin, and since the unevenness of the surface of the plastic circuit board 11 can be absorbed by the fluidity of the liquid resin, it is possible to bond the plastic circuit board 11 without entraining air bubbles even in the semi-cured state. As a result, the notch space 1
The cavity 14 is formed by 2 and the heat dissipation plate 13.

Next, as shown in FIG. 2B, the laminated body 1
A desired one or a plurality of through-holes 17 are formed at predetermined positions 6 by using a drilling means such as a drill or punching. The through hole 17 is formed in the plastic circuit board 1.
Since 1 and the heat sink 13 are formed in communication with each other, they can be formed accurately and efficiently. In addition, in forming the through-hole 17, a plurality of laminated bodies 16 may be overlapped and punched at once.

Next, as shown in FIG. 2C, the through hole 1
The rivet 18 is inserted into the rivet 7, and the rivet is tightened by press working to join the plastic circuit board 11 and the heat dissipation plate 13. The adhesive resin layer 15 is cured by heating the plastic circuit board 11 and the heat radiating plate 13 with rivets 18 for joining and then heating at 150 ° C. for about 30 minutes. The heat dissipation type BGA package 10 uses the rivet 18 to make the plastic circuit board 1
1 and the heat sink 13 can be firmly joined. Also,
The adhesive resin layer 15 can prevent moisture from being adsorbed in the gap between the joint surfaces of the plastic circuit board 11 and the heat dissipation plate 13, and can prevent the sealing resin from flowing in.

In the present embodiment, the rivet 18 is used as the tightening member. For example, a rivet with a collar is inserted into the through hole 17 and only one end of the rivet with a collar is pressed to be joined. May be. It is also possible to insert a screw into the through hole 17 and tighten the screw and the nut to join them.

The adhesive resin layer 15 of the present embodiment heats the applied thermosetting adhesive resin to a semi-cured state to temporarily bond the plastic circuit board 11 and the heat sink 13, and after the rivet 18 is tightened, heat cured. However, the heat dissipation plate 1 of the plastic circuit board 11 is used as the adhesive resin layer.
A non-hygroscopic adhesive sheet having substantially the same size as the outer shape of the plastic circuit board 11 is adhered to the joint surface facing 3 (or the joint surface facing the plastic circuit board 11 of the heat dissipation plate 13). You may form it. In this case, the plastic circuit board 11 and the heat dissipation plate 13 are overlapped with each other via the adhesive sheet to form a laminated body 16 in a temporarily joined state, which is fastened and fastened with a fastening member, but is not cured by heating thereafter. Not performed. Since the adhesive resin layer is joined by the tightening member with the non-hygroscopic adhesive sheet sandwiched, it is possible to form a joint surface having no gap and no moisture absorption.

Further, an adhesive resin layer is provided between the plastic circuit board 11 and the heat dissipation plate 13, and the plastic circuit board 11 is provided.
It may be formed by mounting a thermosetting adhesive resin sheet having substantially the same size as the outer shape. In this case, the adhesive resin sheet (adhesive resin layer) is heated and cured at 150 ° C. for about 30 minutes after the plastic circuit board 11 and the heat dissipation plate 13 are fastened and joined by the fastening member.

In the heat dissipation type BGA package 10 according to the present embodiment, as shown in FIG. 3, the semiconductor chip 19 is mounted on the exposed surface of the heat dissipation plate 13 at the bottom of the cavity 14.
The semiconductor chip 19 and the plastic circuit board 11 are connected by the bonding wires 20, the semiconductor chip 19 is sealed with the sealing resin 21, and the solder balls 22 are attached to the surface of the plastic circuit board 11 to form the semiconductor device 2.
Used as 3.

In the above embodiment, the materials for the heat sink, rivets, screws, nuts, etc., and the material for the adhesive resin forming the adhesive resin layer are not particularly limited. Further, in the above-described embodiment, the BGA type substrate is given as an example of the plastic circuit board 11, but P
It may be a GA (pin grid array) type or the like and is not particularly limited.

[0024]

In the heat dissipating BGA package according to the first aspect of the present invention, there is provided an adhesive resin layer between the plastic circuit board and the heat sink, and one or a plurality of holes in which the laminated body of the plastic circuit board and the heat sink are communicated with each other. Since it is equipped with a tightening member that is inserted into the through hole of the plastic circuit board to tighten and bond the laminated body, the plastic circuit board and the heat sink are mechanically bonded to improve the bonding strength, and the adhesive resin layer heats the plastic circuit board and the heat dissipation plate. There is no adsorption of moisture on the joint surface of the plate,
The airtightness reliability of the semiconductor chip can be improved. Further, it is possible to prevent the sealing resin from flowing into the joint surface between the plastic circuit board and the heat dissipation plate, and it is possible to prevent the reliability of the airtightness of the semiconductor chip from being lowered. Further, since the through hole into which the tightening member is inserted communicates and pierces the laminated body of the plastic circuit board and the heat dissipation plate, the tightening member can be surely inserted. Further, since the warp of the plastic circuit board is suppressed, the coplanarity of the solder balls can be kept normal.

In the method for manufacturing a heat-dissipating BGA package according to any one of claims 2 to 5, the heat-dissipating BGA package is manufactured by joining a metal heat-dissipating plate to one surface of a plastic circuit board having a cutout space at the center. A step of forming a laminate in a temporarily joined state by laminating a plastic circuit board and a heat sink with an adhesive resin layer in between, a step of forming one or a plurality of through holes in the laminate, and a step of forming a through hole Since the step of inserting and tightening the tightening member to join the plastic circuit board and the heat sink is included, the adhesive resin layer prevents the adsorption of water on the joint surface of the plastic circuit board and the heat sink, and also the sealing resin. Can be prevented from flowing into the joint surface, and a heat dissipation type BGA package can be obtained in which the reliability of the airtightness of the semiconductor chip is prevented. Further, since the through hole for inserting the tightening member is formed in the laminated body in which the plastic circuit board and the heat dissipation plate are superposed, the tightening member can be easily inserted into the through hole.

Particularly, in the method for manufacturing the heat dissipation type BGA package according to the third aspect, the adhesive resin layer is formed in a semi-cured state by applying a thermosetting adhesive resin on the joint surface and heating it to form a semi-cured state. It is easy and the plastic circuit board and the heat sink can be joined together without causing displacement. Further, by forming the through hole in the laminated body, the plastic circuit board and the heat dissipation plate can be accurately joined by the tightening member without causing positional displacement.

Particularly, in the method for manufacturing a heat dissipation type BGA package according to claim 4, a non-hygroscopic adhesive sheet having substantially the same size as the outer shape of the plastic circuit board is attached to the bonding surface of the adhesive resin layer. Since it is formed in the same manner, temporary joining is easy, the plastic circuit board and heat sink can be joined without causing positional displacement, and further, through holes can be formed in the laminated body in this state, causing positional displacement. Instead, it can be joined accurately with a tightening member. Further, since the adhesive resin layer is a non-hygroscopic adhesive sheet, it does not need to be heat-cured and can prevent the heat-radiating BGA package from warping due to heating.

Particularly, in the method for manufacturing a heat dissipation type BGA package according to claim 5, the adhesive resin layer is formed by mounting a thermosetting adhesive resin sheet having substantially the same size as the outer shape of the plastic circuit board. Since the temporary joining is easy, the plastic circuit board and the heat dissipation plate can be joined without causing positional displacement, and the through hole can be formed in the laminated body in this state, and the tightening member can be secured without causing positional displacement. Can be joined with high precision.

[Brief description of drawings]

1A and 1B are respectively a front sectional view and a plan view of a heat dissipation type BGA package according to an embodiment of the present invention.

2A to 2C are explanatory views of a method for manufacturing the same heat dissipation type BGA package.

FIG. 3 is an explanatory diagram of a mounting form of a semiconductor chip on the heat dissipation type BGA package.

FIG. 4 is a vertical cross-sectional view for explaining a conventional heat dissipation type BGA package.

FIG. 5 is an explanatory diagram of a mounting form of a semiconductor chip on a heat dissipation type BGA package of a conventional example.

[Explanation of symbols]

10: heat dissipation type BGA package, 11: plastic circuit board, 12: notch space, 13: heat dissipation plate, 14: cavity, 15: adhesive resin layer, 16: laminated body, 17: through hole, 18: rivet, 19: Semiconductor chip, 20: bonding wire, 21: sealing resin, 22: solder ball,
23: Semiconductor device

Claims (5)

[Claims] 1. A heat dissipation type BGA package in which a metal heat dissipation plate is joined to one surface of a plastic circuit board having a cutout space in the center, and an adhesive resin layer is provided between the plastic circuit board and the heat dissipation plate, In addition, the heat dissipation type BGA is characterized by including a tightening member which is inserted into one or a plurality of through holes which are formed by communicating the laminated body of the plastic circuit board and the heat dissipation plate, and which clamps and joins the laminated body. package. 2. A heat-dissipating mold B in which a metal heat-dissipating plate is joined to one surface of a plastic circuit board having a cutout space in the center thereof.
In the method of manufacturing a GA package, a step of stacking the plastic circuit board and the heat dissipation plate with an adhesive resin layer interposed therebetween to form a laminate in a temporarily joined state, and forming one or a plurality of through holes in the laminate. A method of manufacturing a heat dissipation type BGA package, comprising: a step of forming a hole; and a step of inserting a tightening member into the through hole and tightening the same to bond the plastic circuit board and the heat dissipation plate. 3. The heat dissipation type BGA package manufacturing method according to claim 2, wherein the adhesive resin layer is formed in a semi-cured state by applying a thermosetting adhesive resin on the bonding surface and heating. A method of manufacturing a heat dissipation type BGA package. 4. The method for manufacturing a heat dissipation BGA package according to claim 2, wherein the adhesive resin layer has a non-hygroscopic adhesive sheet having substantially the same size as the outer shape of the plastic circuit board on the bonding surface. A method for manufacturing a heat dissipation type BGA package, which is characterized in that it is formed by wearing. 5. The method for manufacturing a heat dissipation type BGA package according to claim 2, wherein the adhesive resin layer is mounted with a thermosetting adhesive resin sheet having substantially the same size as the outer shape of the plastic circuit board. A method of manufacturing a heat dissipation type BGA package, which is characterized in that