JP2002374062A - Fixation method for flexible printed-circuit board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a fixation method for a flexible printed-circuit board which can enhance mounting quality, when an electronic component is mounted. SOLUTION: The surface of a conveyance pallet 104 is coated thin with a solvent-type adhesive 16 by a spray 14, and the flexible printed-circuit board 10 is aligned with, and pasted on its adhesive coated face by using a positioning jig 112. Thereby, the whole backside of the circuit board 10 is bonded to the conveyance pallet 104, and the occurrence of the floatation or the flexure of the circuit board 10 is suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for fixing a flexible printed circuit board to a base member for mounting electronic components on the flexible printed circuit board in a planar manner.

[0002]

2. Description of the Related Art When electronic components are mounted on a printed circuit board by reflow, usually, cream solder is printed on a component mounting portion (electrode land) on a substrate surface using a metal mask or the like, and then the electronic components are mounted. In this state, soldering is performed by passing through a reflow device and heating to a predetermined temperature. In addition, in mounting a flexible printed circuit board (FPC) having flexibility, the board itself needs to be kept flat by the above-described solder printing and component mounting processes, and also by automatic conveyance by a conveyor to a reflow device. The substrate is handled by being fixed to a flat base member such as a pallet.

FIGS. 5 and 6 show a conventional example in which a flexible printed circuit board is fixed to a transport pallet. Conventionally, the flexible printed circuit board 100 is fixed to the transport pallet 104 with an adhesive tape 102. In the case of a rectangular board as shown in the figure, the flexible printed circuit board 100 is placed on the transport pallet 104, and the board is manually moved. Adhesive tape 10 near the four corners while holding down
It is fixed at 2.

The transport pallet 104 is formed of a heat-resistant material such as metal or glass, and has two reference holes 106 formed at the edge of the plate for solder printing and setting the components in the apparatus during component mounting. ing. In addition, the reference hole 1
Two positioning holes 108 whose relative positions are aligned with the reference holes 106 are formed closer to the center of the substrate than 06. And the above-mentioned flexible printed circuit board 10
0 is fixed to the transport pallet 104, the transport pallet 1
The positioning holes are inserted into two pins 114 of a positioning jig 112 such that the reference holes 110 provided on the flexible printed circuit board 100 overlap the positioning holes 108 of the substrate 04.

[0005] Incidentally, in such fixing with the adhesive tape 102, the fixing place and the number of fixing are appropriately changed according to the shape and size of the substrate.

[0006]

However, in the above-described conventional method of fixing a substrate, only the corners and the outer peripheral portion of the flexible printed circuit board are partially fixed. For this reason, even if the operator pays attention, the substrate may be lifted or bent. If cream solder is printed on the board surface and the components are mounted in a state where the flat surface is not maintained, solder printing misalignment and component mounting position misalignment increase the frequency of soldering failures and increase the mounting quality. Is reduced.

[0007] In addition, the work of fixing and removing the substrate is complicated by the trouble of attaching the adhesive tape to each fixing portion and removing the adhesive tape one by one after mounting.

On the other hand, in Japanese Patent Application Laid-Open No. Hei 7-162103, a double-sided tape is attached to the back surface of a flexible printed circuit board, electronic components are mounted on the front surface, and the back surface side of the substrate is attached to a base substrate as a product. The technology is described. This is because the release sheet floats due to the difference in thermal expansion between the double-sided tape and the release sheet, or the entire board due to the difference in thermal expansion between the flexible printed circuit board and the double-sided tape, which is caused by heat applied during reflow. In order to suppress the deformation of the substrate, the shape of the double-sided tape and the release sheet is divided into a plurality of sections with respect to the bonding surface (entire back surface) of the substrate.

However, the double-sided tape used here is for attaching the flexible printed circuit board to the base board after the components are mounted, and for maintaining the flatness of the board in the mounting process as described above. Not for fixing. Also, the deformation of the substrate, which is a problem here,
This is caused by using the heated double-sided tape together with the flexible printed circuit board as it is for attaching to the base substrate. Therefore, the present invention
The purpose of the double-sided tape, the factor of deformation of the substrate and the problem to be solved are different.

In view of the above facts, the present invention improves the mounting quality when mounting electronic components on a flexible printed circuit board, and facilitates the work of fixing and removing the board to and from a base member for keeping the board flat. An object of the present invention is to provide a method for fixing a flexible printed circuit board.

[0011]

According to the first aspect of the present invention, in order to achieve the above object, the flexible printed circuit board is fixed to a base member in a planar shape for mounting electronic components on the flexible printed circuit board. A method for fixing a flexible printed circuit board, wherein a liquefied adhesive is sprayed and applied to a fixing area of the base member to which the flexible printed circuit board is fixed, and the fixing area of the base member is Adhering the flexible printed circuit board.

According to the first aspect of the present invention, the liquefied adhesive is sprayed and applied to the fixing area of the flexible printed circuit board in the base member using, for example, a spray type spray (aerosol). Then, by attaching the flexible printed circuit board to the fixing area, the entire back surface of the flexible printed circuit board is adhered and fixed to the base member. Therefore, the flexible printed circuit board is kept in a flat state by suppressing partial floating and bending. As a result, defective soldering of electronic components during reflow is improved, and mounting quality is improved.

[0013] Further, since the adhesive application operation here only involves spraying the adhesive, it does not require the trouble of thinly spreading the adhesive as compared with, for example, a tube-type adhesive or the like, and is quick and easy. It can be applied almost uniformly without spots. Further, there is no need to attach an adhesive tape to each fixing portion as in the related art. On the other hand, when removing the flexible printed circuit board from the base member after component mounting,
It is simple because the end of the substrate is simply flipped up and the entire substrate is peeled off from the fixing area. Therefore, the work of fixing to and removing from the base member becomes easy.

Further, the peel strength of the adhesive in the first aspect may be 5 to 100 N / m as described in the second aspect. Accordingly, the flexible printed circuit board can be fixed to the base member in a desired flat state, and the flexible printed circuit board has good releasability when peeled from the base member and can be removed without damaging the board.

According to a third aspect of the present invention, there is provided a method of fixing a flexible printed circuit board to mount a flexible printed circuit board on a base member for mounting electronic components on the flexible printed circuit board. At least one surface side of the sheet-shaped double-sided adhesive member is attached to a predetermined area including a mounting location where the electronic component is mounted on the flexible printed circuit board at least in a fixing area of the member where the flexible printed circuit board is fixed. And a step of attaching the flexible printed circuit board to the other side of the double-sided adhesive member.

According to the third aspect of the present invention, one surface of the sheet-shaped double-sided adhesive member is attached to a fixing region of the base member to which the flexible printed circuit board is fixed. This double-sided adhesive member, for example, to cover the entire area of the fixed area as a single member of the same shape as the flexible printed circuit board, or divided into a plurality,
The electronic component may be attached only to a predetermined area including a mounting portion where the electronic component is mounted on the flexible printed circuit board. Then, by attaching a flexible printed circuit board to the other surface of the double-sided adhesive member, the back surface of the flexible printed circuit board is adhered and fixed to the base member.

Thus, at least a component mounting portion (a predetermined region in the fixed region) of the flexible printed circuit board.
In this case, floating and bending are surely suppressed, so that defective mounting of electronic components is improved.

According to a fourth aspect of the present invention, in the method of fixing a flexible printed circuit board according to the third aspect, the peel strength of the double-sided adhesive member is greater on one side than on the other side. .

According to the fourth aspect of the present invention, since the peel strength of the other side of the double-sided adhesive member is made larger than that of the one side, the double-sided adhesive member is firmly bonded to the base member.
As a result, instead of replacing the double-sided adhesive member each time it is mounted, it is repeatedly used while sticking to the base member and replacing and using the flexible printed circuit board until the peeling strength on one side becomes a predetermined force or less. Becomes possible. Therefore, especially in mass production of substrates, the work of attaching the double-sided adhesive member to the base member is greatly reduced,
Productivity is improved.

Further, the peel strength of the one surface side and the other surface side in claim 4 is, as described in claim 5, that the one side is 10%.
0 N / m or more and 500 N / m or less, 5 N / m on the other side
It may be more than 100 N / m or less. As a result, the double-sided adhesive member is firmly adhered to the base member and can be used repeatedly.Also, the flexible printed circuit board attached to the other surface is fixed in a desired flat state, and the double-sided adhesive member is Is also good.

According to a sixth aspect of the present invention, in the method for fixing a flexible printed circuit board according to any one of the third to fifth aspects, the double-sided adhesive member has an area larger than that of the fixing region. It is characterized by having.

According to the sixth aspect of the present invention, since the area of the double-sided adhesive member is larger than the fixed area of the flexible printed circuit board, that is, the area of the double-sided adhesive member to be bonded to the base member side is larger than the substrate side. Therefore, it is strongly bonded to the base member side. This prevents a double-sided adhesive member from being attached to the side of the substrate to be peeled, for example, when the substrate is repeatedly used by replacing the substrate.

According to a seventh aspect of the present invention, in the method of fixing a flexible printed circuit board according to the sixth aspect, a part of the fixing region is exposed at a periphery of the double-sided adhesive member in a state of being attached to the base member. It is characterized in that an escape portion is provided.

According to the present invention, when the double-sided adhesive member is attached to the base member, for example, an adhesive member provided by chamfering a corner of the double-sided adhesive member or forming a notch in a side portion is provided. Due to the clearance of the peripheral edge, a part of the fixing area is exposed without being covered with the double-sided adhesive member, and the exposed part is a non-adhesive part where a part of the peripheral edge of the flexible printed circuit board is not adhered. Thus, only by flipping up and peeling off the non-adhesive portion of the peripheral edge of the substrate, the substrate can be easily peeled off while the double-sided adhesive member remains on the base member.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS [First Embodiment] An embodiment of the present invention will be described below with reference to the drawings. 1 and 2
1 shows a method for fixing a flexible printed circuit board according to a first embodiment of the present invention.

The flexible printed circuit board 10 is fixed on the same transport pallet 104 as the conventional one using a positioning jig 112.

In this embodiment, first, the transport pallet 1
A spray 14 sprays a solvent-type adhesive 16 in a mist over a surface wider than a fixing area 12 (an area surrounded by a dashed line in FIG. 1) on the surface of the flexible printed circuit board 10. Apply thin and even. This spray type adhesive uses "Spray Glue 55 (trade name)" manufactured by Sumitomo 3M, and has a peel strength of 80 N /.
m.

Next, with the adhesive application side of the transport pallet 104 facing upward, each positioning hole 108 is inserted into the positioning jig 11.
The transport pallet 104 is set on the positioning jig 112 by being inserted through each of the pins 114 of FIG. Here, pin 11
4 has a tapered end portion 114A,
The positioning holes 108 are designed to be easily inserted.

Further, the flexible printed circuit board 1
0 with the component mounting surface facing upward, and each reference hole 18
4, the flexible printed circuit board 10 is attached to the adhesive applied surface of the transport pallet 104. At this time, the flexible printed circuit board 10 is fixed to the fixed area 12 of the transport pallet 104 by the positioning jig 112.
Is aligned and pasted. In this attaching operation, for example, if the flexible printed circuit board 10 is slightly curved and is gradually attached from the end portion on the reference hole 18 side to the other end portion, it is easily attached in a planar shape. be able to.

Finally, when the transport pallet 104 is removed from the positioning jig 112, a state in which the flexible printed circuit board 10 is fixed to the transport pallet 104 as shown in FIG. The flexible printed circuit board 10 has its entire back surface adhered to the transport pallet 104 to suppress the occurrence of floating and bending.

In the mounting process, the transport pallet 104 is set in the apparatus using the reference hole 106 as a reference for positioning.
In this apparatus, cream solder is automatically printed via a metal mask on each electrode land (not shown) provided on the mounting portions 20A, 20B, and 20C of the flexible printed circuit board 10, and electronic components are mounted. In this state, when the transport pallet 104 is sent to a reflow furnace, the pallet is heated by hot air and the electronic components are soldered. Then, when the substrate is peeled off from the transport pallet 104, the flexible printed circuit board 10 on which the electronic components are mounted is completed.

As described above, in the method of fixing the flexible printed circuit board 10 according to the present embodiment, the adhesive 16 applied to the fixing area 12 of the transport pallet 104 is used.
Thereby, the entire back surface of the flexible printed circuit board 10 is adhered to the transport pallet 104, so that floating and bending of the board are suppressed. As a result, the printing displacement of the cream solder and the displacement of the component mounting position are less likely to occur,
Soldering defects are improved, and the mounting quality is improved.

Further, in this embodiment, since the adhesive 16 is merely sprayed from the spray 14 and applied, it can be applied quickly, easily, and almost uniformly without unevenness.
After the components are mounted, the flexible printed circuit board 10
When removing the substrate from the transport pallet 104, the end of the substrate can be flipped up and easily peeled off. Therefore, the work of fixing to and removing from the transport pallet 104 is simplified.

Further, the peel strength of the adhesive 16 is 80 N /
m (5 to 100 N / m), the flexible printed circuit board 10 is securely fixed to the transport pallet 104 while the flat state is maintained. Further, since the peelability when peeling the substrate from the transport pallet 104 is good,
There is no possibility that the substrate is damaged by a strong tensile force.

Since various types of spray-type adhesives having different strengths are commercially available, the peel strength can be arbitrarily changed in addition to the above values by using them. Further, even when the spray 14 of the present embodiment is used, for example, the peeling strength can be suppressed to about 5 N / m by making the spraying time extremely short and applying a small amount of adhesive. However, considering the compatibility between the fixing of the substrate and the releasability as described above, the peel strength is preferably in the range of 5 to 100 N / m.

In this embodiment, the substrate can be mounted about 10 to 20 times by applying the adhesive once.

[Second Embodiment] Next, a second embodiment of the present invention will be described. In the second embodiment, a double-sided adhesive sheet is used for fixing a flexible printed circuit board. The same components as those described in the first embodiment are denoted by the same reference numerals, and description thereof is omitted. I do.

FIGS. 3 and 4 show a method for fixing a flexible printed circuit board according to a second embodiment of the present invention. Here, as shown in FIG.
04 fixed area 12 is substantially rectangular and chamfered at one corner 2
The double-sided adhesive sheet 22 provided with No. 1 is attached.

The double-sided adhesive sheet 22 is larger in length and width than the fixed area 12 having the same area as the flexible printed circuit board 10, and has a peel strength (adhesive strength) on the back surface 22 A side to be attached to the transport pallet 104. Strength) is about 172.5 N / m (100 N / m or more and 500 N / m or less), and the peel strength (adhesion strength) on the surface 22B side is about 13 N / m (5 N / m or more and less than 100 N / m). I have. Further, a positioning jig 11 is provided near the end of the sheet.
A positioning hole 24 to be inserted into the second pin 114 is formed. In addition, for this double-sided adhesive sheet, “Posting tape (trade name) / 561W” manufactured by Sumitomo 3M is used.

Then, the flexible printed circuit board 10
Is fixed to the transport pallet 104, the transport pallet 1
After setting the 04 on the positioning jig 112, the positioning holes 24 of the double-sided adhesive sheet 22 are inserted into the pins 114, and the back surface 22 </ b> A side of the double-sided adhesive sheet 22 is attached to the transport pallet 104 so as to cover the fixing region 12. . Then
The corners of the fixed area 12 corresponding to the chamfers 21 are partially covered without being covered with the double-sided adhesive sheet 22.

Further, the flexible printed circuit board 1
When the zero reference hole 18 is inserted through the pin 114 of the positioning jig 112 and attached to the front surface 22B side of the double-sided adhesive sheet 22, the flexible printed circuit board 10 is flatly placed on the transport pallet 104 as shown in FIG. It is fixed and only the corner 26 corresponding to the chamfer 21 of the double-sided adhesive sheet 22 is in a state where it is not adhered (non-adhered part).

As described above, the method using the double-sided adhesive sheet 22 for fixing the flexible printed circuit board 10 also
Since almost the entire back surface of the substrate can be adhered to the transport pallet 104, the occurrence of floating and bending can be suppressed, and the mounting quality can be improved.

The peel strengths of the back surface 22A and the front surface 22B of the double-sided adhesive sheet 22 are set to the above-mentioned values, and the area of the double-sided adhesive sheet 22 is made larger than that of the fixed region 12 so as to be larger than the flexible printed circuit board 10 side. By increasing the bonding area with the transport pallet 104 side, the transport pallet 10 is formed on the back surface 22A side of the double-sided adhesive sheet 22.
4, the bonding strength of the flexible printed circuit board 10 and the releasability of the flexible printed circuit board 10 are compatible on the surface 22B side, and the double-sided adhesive sheet 22 can be used repeatedly.

The flexible printed circuit board 10
When peeling off the double-sided adhesive sheet 22 from the double-sided adhesive sheet 22, it is possible to easily peel off only the flexible printed circuit board 10 while leaving the double-sided adhesive sheet 22 on the transport pallet 104 simply by turning up the corner 26 and peeling off.

Table 1 below shows data obtained by comparing the mounting defect rate of the connector between the conventional method and the board fixing method of the present embodiment, and Table 2 shows the relationship between the replacement time of the double-sided adhesive sheet and the defective rate. Is shown.

[0046]

[Table 1]

[0047]

[Table 2]

As can be seen from the results shown in Table 1, in the fixing method using the double-sided adhesive sheet, the defective mounting rate of the connector is significantly improved as compared with the conventional fixing method using an adhesive tape. From the data in Table 2, it can be seen that there is no problem even if the double-sided adhesive sheet is used repeatedly up to about 10 times. Thereby, the work of attaching the double-sided adhesive sheet 22 to the transport pallet 104 is greatly reduced, and the productivity is improved.

The double-sided adhesive sheet is mounted on the mounting portions 20A, 20B, 20B of the flexible printed circuit board 10.
You may make it stick to only the predetermined area | region corresponding to C. Also, regarding the chamfering of the corners of the adhesive sheet provided to facilitate peeling of the substrate from the double-sided adhesive sheet, notches or the like may be formed in the side portions, and these may be appropriately changed according to the shape of the substrate and the like. can do.

[0050]

According to the method of fixing a flexible printed circuit board of the present invention, the mounting quality when mounting electronic components is improved, and further, the fixing of the board to a base member for keeping the board flat. And the removal work becomes easy.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view illustrating a method for fixing a flexible printed circuit board according to a first embodiment of the present invention.

FIG. 2 is a perspective view showing a fixed state of the substrate of FIG. 1;

FIG. 3 is an exploded perspective view showing a method of fixing a flexible printed circuit board according to a second embodiment of the present invention.

FIG. 4 is a perspective view showing a fixed state of the substrate of FIG. 2;

FIG. 5 is an exploded perspective view illustrating a conventional method of fixing a flexible printed circuit board.

FIG. 6 is a perspective view showing a fixed state of the substrate of FIG. 5;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Flexible printed circuit board 12 Fixed area 16 Adhesive 20A, 20B, 20C Mounting part (mounting place) 21 Chamfering (escape part) 22 Double-sided adhesive sheet (double-sided adhesive member) 22A Back side (one side) 22B Front side (other side) 104 Transport Pallet (base member)

Claims (7)

[Claims] 1. A method for fixing a flexible printed circuit board to a base member for mounting electronic components on the flexible printed circuit board, the method comprising: fixing the flexible printed circuit board to a base member in a planar manner; A step of spraying and spraying a liquefied adhesive in a mist state on a fixing area where the fixing is performed, and a step of attaching the flexible printed circuit board to a fixing area of the base member. How to fix circuit boards. 2. The peel strength of the adhesive is 5 to 100 N /
2. The method for fixing a flexible printed circuit board according to claim 1, wherein m is set to m. 3. A method for fixing a flexible printed circuit board to a base member, wherein the flexible printed circuit board is fixed to a base member for mounting electronic components on the flexible printed circuit board, wherein at least the flexible printed circuit of the base member is provided. A step of attaching one surface side of a sheet-shaped double-sided adhesive member to a predetermined area including a mounting location where the electronic component is mounted on the flexible printed circuit board in a fixed area where the substrate is fixed; Adhering the flexible printed circuit board to the other surface of the flexible printed circuit board. 4. The method for fixing a flexible printed circuit board according to claim 3, wherein the peel strength of the double-sided adhesive member is larger on one surface side than on the other surface side. 5. The peel strength of the one surface is 100 N / m or more and 500 N / m or less, and the peel strength of the other surface is 5 N / m or less.
5. The method for fixing a flexible printed circuit board according to claim 4, wherein the value is not less than N / m and less than 100 N / m. 6. The method for fixing a flexible printed circuit board according to claim 3, wherein the double-sided adhesive member has an area larger than that of the fixing region. 7. A flexible printed circuit according to claim 6, wherein a relief portion is provided at a peripheral edge of said double-sided adhesive member to expose a part of said fixing region in a state of being attached to said base member. How to fix the substrate.