JP2000031323A - Manufacturing method of BGA with heat sink and reinforcing plate - Google Patents

Abstract

(57) Abstract: A BGA having a heat radiating plate and a reinforcing plate capable of obtaining a structure of a package for a BGA semiconductor device in a short time without causing a problem in positional accuracy of bonding a TAB tape and a metal plate. It is to provide a manufacturing method of. One side of a metal plate as a reinforcing plate having a thickness substantially equivalent to the thickness of a semiconductor element is sequentially formed of a plastic base material layer and a copper foil layer manufactured without using an adhesive. A TAB tape material 20 is prepared. The copper foil layer 1 of the tape material 20 is photo-etched to form a wiring pattern 1a, a solder ball pad portion 5 is formed on the wiring pattern, and the inner lead 14 is plated. Thereafter, a device hole 6 for mounting an IC chip is punched out of the tape material 20 by a press, and a metal plate 7 serving as a heat sink is formed on the opposite surface of the tape material 20 where the copper foil layer 1 is not formed. Attach with adhesive.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a BGA (ball grid array) manufactured in the form of a tape or a sheet, such as a TAB tape, and more particularly to a BGA having a heat radiating plate called a heat spreader and a reinforcing plate called a stiffener. is there.

[0002]

2. Description of the Related Art In recent years, BGA (Ball Grid Array)
A structure of a package for a semiconductor device called “a semiconductor device package” has been proposed.

FIG. 3 shows an example of a BGA of a type called a tape BGA, and shows an outline of an upper surface before mounting an IC chip. 6 is the device hole, 5
Is a bonding portion (solder ball pad portion) for bonding the solder ball 9, and the solder ball pad portion 5 is formed in a circular shape by a region where the solder resist 4 does not exist. Reference numeral 14 denotes inner leads for wire bonding with the electrodes of the IC chip 11, reference numeral 15 denotes a plastic film, reference numeral 16 denotes a sprocket hole, and reference numeral 17 denotes an adhesive.
Reference numeral 18 designates a lead for connecting the inner lead and the solder ball joint portion of the wiring 23a (FIG. 4), that is, a so-called lead.

A conventional tape-shaped BGA is manufactured by using a TAB tape as a wiring pattern and bonding a package reinforcing plate called a stiffener and a heat radiating plate called a heat spreader with an adhesive.

FIGS. 4A to 4C show a BG according to a conventional method.
It is a cross-sectional view which shows the example of A.

FIG. 4A shows a copper plate 27 as a stiffener.
A TAB tape 20 formed by bonding a copper plate 29 serving as a heat spreader with an adhesive 28 and applying a wiring 23 to a plastic film 21 via an adhesive 22
Are bonded with an adhesive 26, and the wiring 2 of the TAB tape 20 is attached.
3 and an electrode of the IC chip 30 are bonded by wire bonding with a gold wire 32 and sealed with a sealing resin 33. Reference numeral 24 denotes a solder resist, and reference numeral 25 denotes a solder ball provided on the solder ball pad 5.

FIG. 4B shows a TAB tape 20 adhered to a metal plate 42 serving as a stiffener and a heat spreader in which a device hole 6 serving as an IC chip mounting portion is cut out in the form of a bottomed hole with an adhesive 41. Thereafter, it is of the type packaged in the same manner as in (a).

FIG. 4 (c) shows a recess 53 serving as an IC chip mounting portion formed on a copper plate 52 serving as a metal plate serving also as a heat spreader and a stiffener by pressing or the like. It is of the type to be laminated and then packaged in the same manner as in (a).

[0009]

However, the conventional method has the following problems.

(1) This is a problem caused by bonding a TAB tape and a metal plate.

The first problem is the positional accuracy of the bonding between the TAB tape and the metal plate. In order to perform wire bonding with an IC chip without hindrance, very accurate alignment is required, and a problem remains.

The second is that voids may be present in the adhesive layer when the TAB tape and the metal plate are bonded together. If there is a void in the adhesive layer, there is a risk that swelling or peeling may occur due to resin sealing or heating with an assembly or the like. The existence of voids cannot be confirmed unless they are peeled off, and the product inspection is a sampling inspection. There is a problem that the reliability of void-related defects cannot be guaranteed.

[0013] Even if these problems are solved, there is a fundamental problem due to the presence of the adhesive. That is, in the wire bonding, the harder the base, the better the work can be performed, and the better the quality and the yield. In the conventional method, a layer of an adhesive 22 for bonding three layers of a TAB tape (three layers of wiring 23 / adhesive 22 / plastic film (polyimide tape) 21) and a stiffener 27, 42 or 5
There are two adhesive layers, the layers of adhesives 26, 41, 51 used for laminating the adhesive. Since the adhesive is soft, it hinders good wire bonding.

(2) The individual problems of the conventional method are as follows.

In the method (a), a copper plate 2 as a stiffener is used.
7 and a copper plate 29 serving as a heat spreader, and a TAB tape 20
The step of laminating with 6 is necessary, and the process becomes twice,
The number of processes increases.

In the method (b), there is a problem in that the IC chip mounting portion of the metal plate serving as the stiffener and the heat spreader is hollowed out. That is, as a method of hollowing out, mechanical processing or etching processing is used, but a method by cutting requires a long time and is not practical.

The method (c) is a method in which the convex portion is cut after forming the concave portion 53 as the IC chip mounting portion by molding and press working. Therefore, the method does not require much time as compared with the method (b), but is simple. It is not possible to drill holes and it becomes oblique. When it is inclined, the distance between the IC chip and the tape wiring becomes longer,
Workability deteriorates. In addition, there is a problem in terms of cost because the amount of gold wire used increases.

Accordingly, an object of the present invention is to solve the above-mentioned problems, and to obtain a structure of a package for a BGA semiconductor device in a short time without causing a problem in positional accuracy of bonding a TAB tape and a metal plate. An object of the present invention is to provide a method of manufacturing a BGA having a heat sink and a reinforcing plate.

[0019]

In order to achieve the above object, a method of manufacturing a BGA with a hot plate and a reinforcing plate according to the present invention comprises a metal plate as a reinforcing plate having a thickness substantially equivalent to the thickness of a semiconductor element. A sheet material that is formed by sequentially covering one side of the sheet material with a plastic substrate layer and a copper foil layer without using a special adhesive, and preparing a sheet material by photoetching the copper foil layer of the sheet material and wiring A step of forming a pattern, a step of forming a solder ball pad portion on the wiring pattern, a step of plating an exposed lead of the wiring pattern, and a step of plating the solder ball pad portion and the plated lead A step of punching a device hole for mounting an IC chip on the sheet material with a press, and a step of forming a copper foil layer of the tape material on the opposite side, It is intended to include a step of pasting a metal plate with a hot plate with an adhesive (claim 1).

In the above, a sheet material is used as a starting material. Instead, a special adhesive is used on one side of a metal plate as a reinforcing plate having a thickness substantially equivalent to the thickness of a semiconductor element. Alternatively, a tape material that is sequentially covered and integrated with a plastic base material layer and a copper foil layer may be prepared (claim 2). This is a manufacturing method in which the above-described manufacturing is performed in a tape shape. Prior to the step of forming the wiring pattern, it is preferable to form a sprocket hole punched by a press (claim 3).

The gist of the present invention is to manufacture a BGA with a heat radiating plate and a reinforcing plate using a three-layer tape or sheet composed of a copper foil, a plastic, and a metal plate manufactured without using an adhesive. Is to do.

At the time of bonding the metal plate on the TAB tape or sheet material having the three-layer structure described above, since the device hole for mounting the IC chip is not formed on the reinforcing plate side, the position of the bonding between the TAB tape and the metal plate is set. No accuracy issues arise. Next, after punching a device hole for mounting an IC chip with a press, a metal plate serving as a heat sink is adhered to the opposite surface of the TAB tape material or sheet material on which the copper foil layer is not formed with an adhesive. In this case, it is sufficient to simply join the two in a planar manner, and accurate positioning of the heat sink is not required. Moreover, the depth of the device hole for mounting the IC chip is determined by the thickness of the reinforcing plate,
The shape of the device hole is such that when the IC chip is mounted in the device hole, the IC chip comes almost right next to the lead of the TAB sheet material or TAB tape material. For this reason, the distance between the lead of the TAB sheet material or TAB tape material and the electrode of the IC chip, that is, the distance required for wire bonding becomes extremely short,
The material used for wire bonding can be saved and the operation time can be reduced.

In addition, since a sheet material or tape material having a three-layer structure of a copper foil having no adhesive, a plastic base material layer, and a metal plate is used, there is basically no room for voids in the structure. Therefore, the reliability of the defect relating to the void is guaranteed.

Further, since a sheet material or tape material having a three-layer structure of a copper foil having no adhesive, a plastic base material layer, and a metal plate is used, the adhesive layer is formed of a heat radiating plate, a sheet material or a tape material. Only the adhesive layer between them can be obtained, and good wire bonding can be achieved.

The thickness of the copper foil forming the wiring pattern is not particularly limited, but is generally 9 to 35 μm from the viewpoint of etching workability and the like. The plastic base material layer is generally a polyimide resin, but may be an epoxy resin, a urethane resin, or the like, depending on the application. Thickness 10
５０50 μm is appropriate.

The metal plate serving as the heat spreader and the stiffener portion is generally a copper plate in terms of workability and thermal conductivity, but may be a copper alloy such as phosphor bronze, a nickel iron-based alloy, or the like. Thickness is 0.1-1mm considering strength and workability
Is appropriate.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on the illustrated embodiment. In order to facilitate understanding, the description will be made assuming that the wiring pattern is the same as that of the related art shown in FIG.

First, as shown in FIG. 1 (a), one side of a metal plate layer 3 made of a copper plate having a thickness substantially equivalent to the thickness of a semiconductor element is made of polyimide resin without using a special adhesive. A sheet material or a tape material which is sequentially covered and integrated with the plastic base material layer 2 and the copper foil layer 1 is prepared. Here, a copper foil layer 1, a plastic substrate layer 2, and a reinforcing plate (stiffener) manufactured without using an adhesive.
A tape material 10 having a width of 70 mm and having a three-layer structure with the metal plate layer 3 was prepared. The dimensions of each layer in the tape material 10 are such that the thickness of the copper foil layer 1 is 18 μm, the plastic substrate layer 2 is a 25 μm polyimide resin, and the metal plate layer 3 is a 200 μm copper plate. This tape material 10 was obtained by requesting Nippon Steel Chemical Co., Ltd. to manufacture it (3a). Next, the following (1) to (6) were performed in this order.

(1) The tape material 10 consisting of the above three layers was punched out by a press to form sprocket holes 16 (see FIG. 3 for the sprocket holes 16).

(2) The wiring pattern 1a is formed on the copper foil layer 1 by photo-etching (corresponding to the lead 18 in FIG. 3).
Was formed (see FIG. 3B). This was formed by applying a photoresist, performing processing such as exposure, development, and backing, and then etching to remove the film. A blank portion 1b corresponding to a device hole of an IC chip mounting portion to be punched later by a press is set to be slightly wider than a region to be punched later by a press.

(3) A photo solder resist 4 (see 4 in FIG. 3) is applied while leaving a solder ball pad portion 5;
Exposure and development were performed to form a solder ball pad portion 5 (see FIG. 3C). Here, a series of operations of photo solder resist coating → exposure → development → curing treatment was performed.

(4) The exposed inner leads (1 in FIG. 3)
4) was plated with gold.

(5) The device hole 6 (see 6 in FIG. 3) at the IC chip mounting portion was punched out with a press (3d).

(6) A heat radiating plate (heat spreader) 7 made of a copper plate is adhered to the opposite side of the tape material 10 on which the wiring pattern 1a is not formed with an adhesive 8 to obtain a finished product.

FIG. 1 (f) shows a completed BGA with a heat sink and a reinforcing plate, with solder balls 9 attached thereto, and device holes 6 attached.
FIG. 1 shows a cross section of a state in which an IC chip 11 is placed inside, an electrode thereof and an inner lead 14 are wire-bonded with a gold wire 12 and sealed with a sealing resin 13.

According to the above manufacturing method, the device hole 6 for mounting the IC chip is not formed on the reinforcing plate side at the time of bonding the TAB tape and the metal plate.
There is no problem of the positional accuracy of the bonding between the B tape material 10 and the metal plate layer 3. Next, when a device hole for mounting an IC chip is punched out with a press, and then a heat sink is attached to the opposite surface with an adhesive, the two may be simply joined to each other. No exact positioning of the is required. In addition, the depth of the device hole for mounting the IC chip is determined by the thickness of the reinforcing plate, and when the IC chip is mounted in the device hole, the depth is almost right beside the lead of the TAB sheet or TAB tape. For this reason,
The distance required for wire bonding between the leads of the TAB sheet or TAB tape and the electrodes of the IC chip becomes extremely short, so that materials used for wire bonding can be saved and operation time can be shortened.

Therefore, the positional accuracy between the hole in the IC chip mounting portion and the wiring pattern and the distance of wire bonding are remarkably improved as compared with the conventional product.

In the above embodiment, the solder balls 9 are electrically floated from the metal plate layer 3 serving as a reinforcing plate. However, the present invention is not limited to this, and as shown in FIG. Copper foil layer 1 and plastic layer 2
The conductive portion 9a may electrically connect the solder ball 9 to the reinforcing plate 3 through a via hole provided through the reinforcing plate 3, and the reinforcing plate 3 may be used as a ground layer.

[0039]

As described above, according to the present invention, T
At the time of bonding the AB tape material or sheet material to the metal plate, there is no device hole for mounting the IC chip on the reinforcing plate side, so that there is no problem in the positional accuracy of the bonding between the TAB tape and the metal plate. Next, after a device hole for mounting an IC chip is punched out with a press, a metal plate serving as a heat sink is attached to the opposite surface of the TAB tape or sheet material with an adhesive. In this case, it is only necessary to precisely join the heat sink, and accurate positioning of the heat sink is not required. Moreover, the depth of the device hole for mounting the IC chip is determined by the thickness of the reinforcing plate, and the depth is almost TAB when the IC chip is mounted in the device hole.
Just next to the lead of sheet material or TAB tape material. For this reason, the distance required for wire bonding between the lead of the TAB sheet material or TAB tape material and the electrode of the IC chip becomes extremely short, and the material used for wire bonding can be saved and the operation time can be shortened. .

Further, since a sheet material or tape material having a three-layer structure of a copper foil having no adhesive, a plastic base material layer, and a metal plate is used, a void is formed in the adhesive layer when the TAB tape is bonded to the metal plate. There is no room for it. Therefore, the reliability of the defect relating to the void is guaranteed.

Further, for the same reason, the adhesive layer becomes only the adhesive layer between the reinforcing plate and the sheet material or the tape material, and good wire bonding can be achieved.

It is also an advantage according to the invention that it can be manufactured with established and already common techniques.

[Brief description of the drawings]

FIG. 1 is a view showing a manufacturing process of a BGA with a heat sink and a reinforcing plate of the present invention.

FIG. 2 is a sectional view showing a modification of the present invention.

FIG. 3 is a plan view schematically showing a BGA pattern.

FIG. 4 shows a BGA with a heat sink and a reinforcing plate according to a conventional method.
FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Copper foil layer 1a Wiring pattern 1b Blank part 2 Plastic (polyimide resin) layer 3 Metal plate layer (copper plate) 4 Solder resist 5 Solder ball pad portion 6 Device hole 7 Heat sink (heat spreader) 8 Adhesive 9 Solder ball 9a Conducting portion DESCRIPTION OF SYMBOLS 10 Tape material 11 IC chip 12 Gold wire 13 Sealing resin 14 Inner lead 15 Plastic film 16 Sprocket hole 17 Adhesive 18 Leading lead

Claims (3)

[Claims] 1. One side of a metal plate as a reinforcing plate having a thickness substantially equivalent to the thickness of a semiconductor element is sequentially covered with a plastic base material layer and a copper foil layer without using a special adhesive, A step of preparing an integrated sheet material; a step of forming a wiring pattern by photoetching a copper foil layer of the sheet material; a step of forming a solder ball pad portion on the wiring pattern; Plating the exposed leads of the above, pressing a device hole for mounting an IC chip on the sheet material having the solder ball pad portion and the plated leads, and pressing the tape material. Attaching a metal plate as a heat sink with an adhesive to the opposite surface where the copper foil layer is not formed. Method of manufacturing the A. 2. A method according to claim 1, wherein one side of the metal plate as a reinforcing plate having a thickness substantially equivalent to the thickness of the semiconductor element is sequentially covered with a plastic base material layer and a copper foil layer without using a special adhesive. A step of preparing an integrated tape material; a step of forming a wiring pattern by photoetching a copper foil layer of the tape material; a step of forming a solder ball pad portion on the wiring pattern; Plating the exposed leads, punching out a device hole for mounting an IC chip with respect to the tape material having the solder ball pad portion and the plated leads, and pressing the tape material. Bonding a copper plate as a heat sink with an adhesive to the surface on the opposite side where the copper foil layer is not formed. The method of production. 3. The method according to claim 1, wherein before the step of forming the wiring pattern,
3. A BGA with a radiator plate and a reinforcing plate according to claim 2, wherein a sprocket hole is formed by punching with a press.
Manufacturing method.