JP2000164750A - Manufacture of semiconductor package - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing a semiconductor package where a flexible circuit board can be corrected for deformation, such as warpage or the like after the flexible circuit board is pasted at the opening of a metal frame. SOLUTION: A sheet-like flexible circuit board 7, pasted at the opening of a metal frame 1 with an adhesive agent, is used as a semiconductor package intermediate product, and the intermediate product is successively transferred to several processes where a semiconductor element 9 is mounted, a wire bonding operation is carried out, a resin sealing operation is performed, and others are carried out for the manufacture of a semiconductor package, where the flexible circuit board 7 is heated so as to be less warped after the circuit board 7 is pasted on the metal frame 1.

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 including a step of attaching a sheet-like flexible circuit board to an opening of a metal frame with an adhesive, and in particular, to reducing deformation such as warpage of the flexible circuit board. The present invention relates to a method for manufacturing a semiconductor package as described above.

[0002]

2. Description of the Related Art A conventional manufacturing apparatus for manufacturing a QFP (Quad Flat Package) uses a FBGA (Fine Pitch Ball Grid A).
There is a demand for a method of manufacturing a semiconductor package capable of manufacturing a CSP (Chip Scale Package) called rray).

[0003] As a part of this, conventionally, a single circuit board having a circuit pattern on one side or both sides, or a plurality of such single circuit boards, are integrated into a sheet as a unit in a metal frame as a carrier frame. Japanese Patent Application Laid-Open Nos. 8-83866 and 9-275 disclose a method for manufacturing a semiconductor package in which a collective circuit board sheet is fixed, semiconductor elements are mounted thereon, and one surface is sealed with resin.
63 and JP-A-9-22963.

Japanese Patent Application Laid-Open No. H08-83866 discloses a metal frame provided with an opening formed of a rectangular through hole, and a single piece of a circuit having a circuit pattern on one side or both sides provided in the opening. A circuit board, which is positioned and supported by mechanical support means, is used as an intermediate product for a semiconductor package, and is transported to each process, so that existing equipment can be used as is to mount semiconductor elements and wire. This is a method for manufacturing a semiconductor package that efficiently performs processes such as bonding and resin sealing. As the support means for positioning and supporting the circuit board on the metal frame, for example, a locking piece formed by cutting and erecting a plate material of the metal frame is used. The circuit board (single BGA product) can be easily removed from the metal frame.

A first advantage of using the above-mentioned intermediate product for a semiconductor package is that a waste portion of a printed circuit board when a conventional strip-shaped printed circuit board is used can be eliminated. That is, in a conventional manufacturing method, a large-sized printed circuit board provided with a predetermined wiring pattern is cut into strips, and the printed board formed in the strip shape is transported to each process to produce a product. However, the use of a single circuit board and supporting it on a metal frame does not cause such waste. A second advantage resides in that processes such as mounting of a semiconductor element, wire bonding, and resin sealing can be efficiently performed using existing facilities as they are.

Japanese Patent Application Laid-Open Nos. 9-27663 and 9-22963 disclose a plurality of single circuit boards in place of the individual single circuit boards described above. The integrated circuit board sheet which is connected and integrated as one unit is handled.

[0007] Typically, FIG.
1 shows an intermediate product (semiconductor circuit element mounting substrate frame) for a semiconductor package disclosed in Japanese Unexamined Patent Publication (Kokai) Publication. The semiconductor circuit element mounting board frame 30 includes a single semiconductor circuit board 32 and a single metal board layer 31 which are connected to side rails 35 by connection tabs 36 and are sequentially linearly arranged. The semiconductor circuit element mounting board 33 is provided via a prepreg layer which is a heat conductive adhesive layer, and as a result, the semiconductor circuit element mounting board 33 is connected in a sheet shape. Reference numeral 34 denotes a positioning reference hole provided in the side rail 35.

According to the intermediate product for a semiconductor package which handles the collective circuit board sheet, a drawback in handling a single circuit board of individual pieces, that is, handling such as transport and positioning of individual circuit boards becomes complicated. It is possible to solve the problem that the quality and the work efficiency of mounting the semiconductor circuit element are reduced due to displacement or damage, and the productivity is significantly impaired.

[0009]

However, in the above-mentioned prior art, there has been no study on a method of attaching the flexible circuit board to the metal frame with an adhesive, and the flexible circuit board generated at the time of the attachment has not been studied. A method for reducing deformation such as warpage has not been established.

On the other hand, the present applicant has developed the following method for manufacturing a semiconductor package. That is, as shown in FIGS. 2 and 3, an opening 2 is provided in a metal frame 1 and a sheet-like flexible circuit board 7 is adhered to the opening with an adhesive to be used as an intermediate product for a semiconductor package. , By transporting this to each process,
This is a method for performing processes such as mounting of the semiconductor element 9, wire bonding, and resin sealing.

According to this manufacturing method, for example, it is only necessary to apply an adhesive to two, three, or four sides of the frame opening in the frame width direction and attach the flexible circuit board 7 with the adhesive. Since connecting tabs and the like are unnecessary, the production of the metal frame 1 and the flexible circuit board 7
Is very easy to handle, and the manufacturing time can be reduced. In addition, the area occupied by the flexible circuit board 7 on the metal frame 1 is small, and an increase in productivity can be realized. That is, as in the conventional case where the individual circuit boards are handled and supported on the metal frame, there is an advantage that the material of the circuit boards is not wasted. Also,
There is also an advantage that processing such as mounting of the semiconductor element 9, wire bonding, and resin sealing can be performed efficiently using existing facilities as they are.

However, in this manufacturing method, the space just below the flexible circuit board 7 is the space of the opening 2, and there is no support by the metal substrate layer 31 as in the case of FIG.
Since only two or three or four sides of the periphery of the flexible circuit board 7 are fixed with an adhesive, the flexible circuit board 7 is warped as shown in FIG. 7 in the attaching step. There's a problem.

When deformation such as warpage occurs in the flexible circuit board, the flatness of the mounting portion of the semiconductor element 9 and the wire bond connection portion on the flexible circuit board deteriorates, and this becomes a major obstacle in mounting the semiconductor and in wire bonding. there is a possibility. In addition, the semiconductor chip is damaged after the step of mounting the chip of the semiconductor element 9, for example, at the time of molding, and becomes unusable in the worst case.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a semiconductor package capable of solving the above-mentioned problems and reducing deformation such as warpage of a flexible circuit board after attaching the flexible circuit board to an opening of a metal frame. It is to provide a manufacturing method.

[0015]

Means for Solving the Problems In order to achieve the above object, the present invention is configured as follows.

According to a first aspect of the present invention, there is provided a method of manufacturing a semiconductor package including a step of attaching a sheet-like flexible circuit board to an opening of a metal frame with an adhesive, wherein the flexible circuit board is attached to the metal frame. Later, the flexible circuit board is heated to reduce the warpage of the flexible circuit board.

According to a second aspect of the present invention, an intermediate product for a semiconductor package is obtained by attaching a sheet-like flexible circuit board to an opening of a metal frame with an adhesive, and is transported to each step. In a method of manufacturing a semiconductor package for performing processes such as mounting of a semiconductor element, wire bonding, and resin sealing, after attaching the flexible circuit board to the metal frame, the flexible circuit board is heated to heat the flexible circuit board. To reduce warpage.

Specifically, as schematically shown in FIG. 1, a sheet-like flexible circuit board is attached to the opening of the metal frame with an adhesive (step (a)), and then the flexible circuit board is For example, vacuum heating is performed at 150 ° C. for 30 minutes to reduce the warpage of the flexible circuit board (step (b)). Next, the obtained intermediate product for a semiconductor package is transported to each step (step (c)), and processing such as mounting of a semiconductor element, wire bonding, and resin sealing is performed (step (d)).

When the flexible circuit board affixed to the metal frame is heated as in the step (b), the metal frame is first stretched, and the flexible circuit board is stretched accordingly. No deformation. Therefore, by heating the flexible circuit board after attaching it to the metal frame, the deformation of the flexible circuit board can be significantly reduced.

In the case of a flexible circuit board, the form of an individual flexible single circuit board having a circuit pattern on one side or both sides, and a flexible circuit formed by combining a plurality of these single circuit boards into one unit as a sheet. Both forms of an integrated circuit board are included.

In the method for manufacturing a semiconductor package according to the first or second aspect, it is preferable that the flexible circuit board is heated in a vacuum (claim 3). In addition, when the flexible circuit board is housed in a rack-shaped jig and heated, the handling is easy (claim 4). Further, it is efficient to heat the flexible circuit board when several tens of metal frames are stacked (claim 5). A copper frame can be used as the metal frame.

In the present invention, the mechanism for reducing the deformation of the flexible circuit board will be described in detail as follows. The flexible circuit board expands when it absorbs moisture.
Then, by heating after attaching the flexible circuit board to the metal frame, the moisture content inside is reduced.
As the moisture inside decreases, the deformation of the flexible circuit board also decreases. Heating is effective even with normal heating,
Heating in a vacuum state is more effective.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on the illustrated embodiment.

FIG. 2 shows a form of an intermediate product for a semiconductor package used in the method of manufacturing a semiconductor package according to the present invention. In the intermediate product for a semiconductor package, a rectangular frame opening 2 (see FIG. 3) is provided on a metal frame 1 as a carrier frame, and the frame opening 2 is formed on one or both sides of a polyimide resin insulating film. A flexible circuit board 7 cut out from a flexible tape (so-called TAB tape) 4 (see FIG. 5) provided with a circuit pattern is attached with an adhesive 8 (see FIG. 4). The sticking of the flexible circuit board 7 is performed on a portion of the peripheral area of the frame opening 2 on the metal frame along two sides in the frame width direction and overlapping with the flexible circuit board after sticking, An adhesive 8 (see FIG. 4) is applied to this portion, and the metal frame 1
The flexible circuit board 7 is attached to the frame opening 2 of FIG. This intermediate product for a semiconductor package is manufactured as follows.

First, as shown in FIG. 3, the metal frame 1 is etched into a copper alloy of 160 mm × 40 mm and 200 μm in thickness to form a 3
A metal frame 1 is prepared by linearly forming and arranging four square holes of 0 mm × 30 mm. By forming the frame openings 2, the side rail regions 1 a and 1 a are left on the two sides (both sides) of the metal frame 1 in the frame width direction in common with the frame openings 2. The partitioned area 1b is left between the openings 2. A plurality of positioning guide holes 3 are formed in the side rail region 1a of the metal frame 1.

Next, as shown in FIG. 5, the flexible circuit board 7 is a coil-shaped 50 μm-thick flexible tape in which a circuit pattern is provided on one or both sides of a polyimide resin insulating film capable of high-density mounting. From a (so-called TAB tape) 4, a 30 mm × 34 mm rectangle is punched out with a die by a press working method using a die (not shown), and the obtained flexible tape cut portion is used as a flexible circuit board 7. The dimensions of the flexible circuit board 7 are the same as the length of the frame opening 2 and the width is larger by 4 mm. The reason why the width of the flexible circuit board 7 is slightly longer than that of the frame opening 2 is to use the protruding portion of the short side of the flexible circuit board 7 as a portion 7b to be adhered to the above-mentioned bonding margin. In addition,
Guide holes 5 for feed positioning are formed at a predetermined pitch on the side of the flexible tape 4.

In this embodiment, the flexible circuit board 7 is formed by connecting four single circuit boards 6, which are the wiring pattern portions of the flexible tape 4, in such a manner that a frame in the shape of a cross remains as a connecting portion 7a. Consisting of However, the flexible circuit board 7 can have any desired shape in which the required number of the single circuit boards 6 are connected.

Next, as shown in FIG.
The adhesive 8 is applied to a portion of the paste margin. That is, the thermosetting adhesive 8 is applied in a straight line using a mechanically controlled dispenser to positions along two sides in the frame width direction at the periphery of each hole which is a peripheral area of the frame opening 2. I do. The length of the portion where the flexible circuit board 7 overlaps with the metal frame 1 is 30 mm, and the adhesive 8 is applied slightly shorter, that is, a 28 mm length is applied inside the portion, and the metal frame 1 and the flexible circuit board are applied. The adhesive 8 was prevented from leaking to a portion other than the portion where 7 overlapped. The curing temperature of the adhesive 8 used here is 250 ° C. Therefore,
100 ° C., 30 seconds + 150 ° C., 30
Perform incomplete curing by heating for a second.

Thereafter, the flexible tape 4 shown in FIG.
The above-mentioned bonded portion 7b of the flexible circuit board 7 obtained by punching the above into a rectangle of 30 mm × 34 mm with a metal mold is superimposed on the adhesive applied portion of the metal frame 1, and 6 kg using a bonding mold heated to 270 ° C. Pressure for 1 second at a pressure of
The flexible circuit board 7 and the metal frame 1 were attached.

These were repeated for one metal frame 1. In this attaching step, since there is no supporting material in the space immediately below the flexible circuit board 7 and the surrounding two sides of the flexible circuit board 7 are merely fixed with an adhesive, the structure is shown in FIG. Thus, the flexible circuit board 7 is likely to be warped.

The flexible circuit board 7 is mounted on the metal frame 1
When the flexible circuit board 7 on which the semiconductor element 3 is mounted is warped as shown in FIG. 7 when the semiconductor element 3 is fixed as shown in FIG. 2, the semiconductor element 3 is damaged during molding.

Therefore, as shown in FIG. 2, after attaching the flexible circuit board 7 to the metal frame 1, that is, after the step (a) in FIG. 1, the flexible circuit board 7 is heated at 150 ° C. for 30 minutes in a vacuum. As a result (step (b) in FIG. 1), the warpage of the flexible circuit board 7 was significantly reduced. The amount of warpage of the flexible circuit board 7 immediately after attachment is 10
It was 0 μm or more, but reduced to 60 μm or less after vacuum heating.

The flexible circuit board is heated in vacuum by
It has been found that handling the flexible circuit board in a rack-shaped jig and heating it with dozens of metal frames stacked on each other is easy and efficient.

Thus, an intermediate product for a semiconductor package was completed.

Next, in order to manufacture the small grid area array type semiconductor package shown in FIG. 6, the obtained intermediate product for a semiconductor package is transported to each step (step (c) in FIG. 1), and the semiconductor is manufactured. Device mounting, wire bonding,
Processing such as resin sealing was performed (step (d) in FIG. 1).

In FIG. 6, the flexible circuit board 60 is one of four flexible circuit boards 7 formed as a single circuit board 6 (FIGS. 2 and 5) continuously in a cross shape. The circuit pattern is formed by the copper foil 13 on one side.

First, in a state where the flexible circuit board 7 is adhered to the metal frame 1, a resist resin 14 is applied to the surface of the circuit pattern on the conductive circuit board 6,
The semiconductor chip 9 is mounted.

Next, wire bonding is performed by the bonding wire 11 between the electrode 9a of the semiconductor chip 9 and the connection pad (gold plating 12b) of the circuit pattern.

Further, a mold resin 10 or a potting material is applied on the semiconductor chip 9 and the bonding wires 11. At this time, the portion of the adhesive 8 described above functions as a weir that prevents the resin from flowing out of the region of the opening 2 on two sides in the width direction. In FIG. 2, reference numeral 16 denotes a mold line.

After resin sealing, solder balls 1 are provided on the lower surface of circuit board 60 as external connection terminals for connection to a mounting board or the like.
5 is attached. A part of the circuit pattern is led out to one side on the other side through a via hole provided with gold plating 12a that penetrates the circuit board 60, and the lead portion is connected to the solder ball 15. In the case of the BGA, solder balls are used as external connection terminals. However, lead pins and the like can be used as external connection terminals in addition to the solder balls as a single-sided resin-sealed semiconductor package.

Finally, by removing the flexible circuit board 7 from the metal frame 1 or the circuit board 60 from the flexible circuit board 7, a small grid area array type semiconductor package can be obtained as a single BGA product.

Normally, a flexible tape for a small grid area array type semiconductor package as described above cannot be produced using a device for manufacturing a lead frame package, and investment for introducing a new device or the like is not possible. Required. However, if the intermediate product for a semiconductor package according to the present embodiment is used, it is possible to manufacture a semiconductor package by using a device for a large lead frame package. That is, according to the method of manufacturing a semiconductor package according to the above-described embodiment, a conventional apparatus for manufacturing a QFP is called a FBGA (Fine Pitch Ball Grid Array).
The SP can be manufactured. Further, the present invention has no limitation on the semiconductor element to be processed, and can be applied to any of memories such as DRAM and SRAM, and logic systems such as CPU and MPU.

[0043]

As described above, according to the present invention, in a method of manufacturing a semiconductor package including a step of attaching a sheet-like flexible circuit board to an opening of a metal frame with an adhesive, A sheet-like flexible circuit board attached to the part with an adhesive is used as an intermediate product for a semiconductor package, and this is transported to each process, so that processing such as semiconductor element mounting, wire bonding, resin sealing, etc. After the flexible circuit board is attached to the metal frame in the method of manufacturing a semiconductor package, the metal frame is first stretched to heat the flexible circuit board, and the flexible circuit board is stretched accordingly. For this reason, according to the present invention, the warpage of the flexible circuit board can be significantly reduced, and therefore, damage to the semiconductor element, for example, during molding after mounting the semiconductor element, can be reduced. . Therefore, according to the present invention, a method for manufacturing a semiconductor package having a high yield can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic view illustrating an example of a method for manufacturing a semiconductor package according to the present invention.

FIG. 2 is a plan view showing an intermediate product for a semiconductor package used in the manufacturing method of the present invention.

FIG. 3 is a plan view showing a metal frame used in the manufacturing method of the present invention.

FIG. 4 is a view showing an opening of a metal frame used in the manufacturing method of the present invention.

FIG. 5 is a view showing a flexible tape used for producing a flexible circuit board used in the manufacturing method of the present invention.

FIG. 6 is a cross-sectional view illustrating an example of a semiconductor package manufactured by the manufacturing method of the present invention.

FIG. 7 is a cross-sectional view illustrating warpage of the flexible circuit board in the embodiment of the method of manufacturing a semiconductor package according to the present invention.

FIG. 8 is a view showing a conventional intermediate product for a semiconductor package.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Metal frame 2 Opening 4 Flexible tape 6 Single circuit board (Wiring pattern part of flexible tape) 7 Flexible circuit board (Cutting part of flexible tape) 8 Adhesive 9 Semiconductor element 10 Mold resin

Claims (6)

[Claims] 1. A method of manufacturing a semiconductor package, comprising: attaching a sheet-like flexible circuit board to an opening of a metal frame with an adhesive, after attaching the flexible circuit board to the metal frame. A method of manufacturing a semiconductor package, comprising heating a substrate to reduce the warpage of the flexible circuit board. 2. An intermediate product for a semiconductor package in which a sheet-like flexible circuit board is adhered to an opening of a metal frame with an adhesive, and is conveyed to each step to mount a semiconductor element. In a method of manufacturing a semiconductor package for performing processes such as wire bonding and resin sealing, after attaching the flexible circuit board to the metal frame, the flexible circuit board is heated to reduce the warpage of the flexible circuit board. A method for manufacturing a semiconductor package, comprising: 3. The method for manufacturing a semiconductor package according to claim 1, wherein the flexible circuit board is heated in a vacuum. 4. The method of manufacturing a semiconductor package according to claim 1, wherein the flexible circuit board is heated by being housed in a rack-shaped jig and heated. Method. 5. The method for manufacturing a semiconductor package according to claim 1, wherein the heating of the flexible circuit board is performed by heating the flexible circuit board in a state where several tens of metal frames are stacked. Production method. 6. The method of manufacturing a semiconductor package according to claim 1, wherein a copper frame is used as said metal frame.