JP3254361B2 - Manufacturing method of flexible printed wiring board - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to relates to a manufacturing method for Awa attaching the component mounting reinforcing plate to a flexible printed circuit board.

[0002]

2. Description of the Related Art Flexible printed wiring boards (hereinafter referred to as F)
After forming a circuit pattern, a component mounting land is provided thereon, and electronic components such as an LSI, a chip resistor, and a chip capacitor are mounted thereon.
C has a very thin thickness of about 0.1 to 0.3 mm,
It is difficult to mount components on an FPC that does not use a reinforcing plate. Therefore, components are mounted while the component mounting reinforcing plate is attached to the FPC. The present invention relates to a high-precision bonding structure of this FPC and a reinforcing plate for component mounting and a method of manufacturing the same, and the prior art is as follows.

A method of manufacturing an FPC is to form a circuit pattern on a polyimide-based copper-clad laminate and form an insulating layer (cover lay).
And subjecting the exposed circuit to a surface treatment such as plating.

[0006] FIG. 6 shows a 3D image formed by a conventional manufacturing method.
One example of an FPC 50 in which the units are integrated is shown. When the product outer shape 51 of the FPC is punched out by a mold, the jig pin insertion hole 52 used for positioning with the reinforcing plate for component mounting is also punched out by the die at the same time to manufacture the FPC. The auxiliary material bonding member 53 for adjusting the thickness of the connector insertion portion protrudes from the surface of the FPC board, and has a thickness of about 0.2 to 0.4 mm.

Next, FIG. 7 shows a component mounting reinforcing plate 54 corresponding to FIG. In FIG. 7, the reinforcing plate for component mounting has various guide holes 55 for component mounting, solder printing, and the like.
In addition, a relief hole 56 for the protrusion 53 of the FPC and a positioning jig pin insertion hole 57 on the component mounting reinforcing plate side are punched and formed by a die.

FIG. 8 shows how the FPC 51 (see FIG. 6) and the component mounting reinforcing plate 54 (see FIG. 7) are bonded together. In FIG. 8A, the bonding jig 5 is used.
8, the component mounting reinforcing plate 54 and the FPC 50 are placed, and the positioning jig pins 59 provided on the bonding jig 58.
Hole 5 for positioning jig pin insertion on reinforcing plate side for component mounting
7 and the positioning jig pin insertion hole 52 of the FPC are made to penetrate and bonded (adhesive processing) using an adhesive.
FIG. 8B shows the state of the FPC which has been removed from the bonding jig after the bonding is completed.

Finally, as shown in FIG. 9 (a), the inspection pin gauge 70 is applied to the FPC which has been pasted to the component mounting reinforcing plate, and all the positions of the positioning jig pin insertion holes 52 are provided. In this case, the passability was checked to confirm the bonding accuracy. As the diameter W of the inspection pin gauge, a value obtained by subtracting (0.05 mm to 0.1 mm) × 2 from the design value of the positioning jig pin insertion hole diameter is used. FIG. 9B shows a positioning jig pin insertion hole 5.
2 is an enlarged view of a region 60 in the vicinity of 2, and shows a state in which an inspection pin gauge 70 is inserted into a positioning jig pin insertion hole 52.

[0008]

By the way, as shown in FIG. 10, the accuracy of the conventional bonding position between the FPC and the reinforcing plate for component mounting, as shown in FIG. Guide holes 55 for use and the like and the center point 6 of the component mounting land 61 formed on the FPC
It is represented by the accuracy with respect to the design value of the distance L (L ₁ , L ₂ , L _3, etc.) to the distance ₂ . In the past, there was no problem in mounting components even with a tolerance greater than about ± 0.3 mm from the design value.

However, in recent years, with the miniaturization of surface mount components (surface mount devices, SMDs) and the miniaturization of the terminal spacing of LSIs, the tolerance for design values has been
A high accuracy of about 0.15 mm or more has been required, and it is no longer possible to cope with the passing judgment method using a conventional pin gauge.

When analyzing the factors of the occurrence of tolerance in the prior art, there are the following three factors.

A. A variation of about ± 0.1 mm occurs between the design value between the component mounting land 61 on the FPC and the positioning jig pin insertion hole 52 on the FPC.

B. Guide hole 5 on component mounting reinforcement plate
A variation of about ± 0.05 mm from the design value between the position 5 and the positioning jig pin insertion hole 57 on the reinforcing plate occurs.

C. Since the diameter of the pin gauge of the jig used when bonding the FPC and the reinforcing plate for component mounting is not the same as the diameter of each hole, it cannot be inserted (0.05 to 0.1 m).
m) A diameter smaller than about 2 is used. Therefore, this difference (gap) is added to the displacement of bonding.

The sum of the factors of the above tolerances (A + B
+ C), a margin at the time of the pin gauge determination is further added to the maximum value ± 0.
25mm variation occurs, with a tolerance of ± 0.3m
The setting of m was the limit. Also, as the material thickness (about 0.5 to 1.5 mm) of the reinforcing plate for component mounting becomes thicker, unevenness of the finished hole diameter is generated due to unevenness of the material fiber on the wall of the positioning jig pin insertion hole, and accurate pin gauge is obtained. Judgment becomes difficult.

Table 1 shows a summary of the factors of the occurrence of tolerance in the above-mentioned conventional technology.

[0016]

[Table 1]

[0017] Therefore, an object of the present invention provides a manufacturing method of a flexible printed wiring board that can match stick at high accuracy without increasing significantly the bonding process of the flexible printed circuit board and the component mounting reinforcement plate It is in.

[0018]

According to a first aspect of the present invention, there is provided a method of manufacturing a flexible printed wiring board , comprising the steps of:
A judgment pattern is provided on the board and the reinforcing board for component mounting is provided on the board.
A determination hole is provided, and the determination pattern and the determination hole are provided.
And a judgment mark paired with
Attach bull-printed wiring board and component mounting reinforcing plate
And characterized in that.

[0019]

[0020]

[0021]

[0022]

According to a second aspect of the present invention, in the method for manufacturing a flexible printed wiring board, a determination pattern provided on the flexible printed wiring board is formed at the same time when a circuit pattern is formed.

According to a third aspect of the present invention, in the method of manufacturing a flexible printed wiring board, the determination hole provided in the component mounting reinforcing plate is formed simultaneously with the component mounting guide hole by punching a die. .

The flexible printed wiring board is mounted on the flexible printed wiring board by using the determination pattern on the flexible printed wiring board according to claim 4 and the determination hole on the reinforcing board for component mounting as a determination mark. In the manufacturing method of bonding the reinforcing plate with the reinforcing plate, the quality is determined based on the transmitted light image of the determination mark.

Next, the means and operation of the present invention will be described in detail.

The above-mentioned A as factors of the conventional tolerance,
Of the factors B and C, A was first addressed. FIG.
At the center point 6 of the component mounting land 61 on the FPC.
2 and the distance between the positioning jig pin insertion holes 52 on the FPC (52a-62a, 52a-62b, 52a-62).
c, etc.) to ± 0.
Since about 1 mm occurs, this machining is abolished and FP
The determination is performed using a “determination pattern” that is simultaneously formed using a photo process or the like at the time of the circuit pattern C. The “judgment mark” is composed of a pair of a “judgment pattern” formed on the FPC and a “judgment hole” formed on the component mounting reinforcing plate.

Next, the judging holes of the component mounting reinforcing plate paired with the judging pattern are the component mounting guide holes (5).
5) at the same time by punching the mold, and the maximum of ± 0.
A variation of 05 mm occurred, but this variation could be eliminated. As a result, the determination hole of the component mounting reinforcing plate of the present invention corresponds to the positioning jig pin insertion hole (57 or the like) on the conventional component mounting reinforcing plate, and the above-described factor of the conventional tolerance. This means that countermeasures have been taken for B.

The conventional jig attachment using the positioning holes is used as an auxiliary, and a judgment mark is added to each of the FPC and the component mounting reinforcing plate, so that the transmitted light image at the time of attachment can be visually or optically evaluated. In the final inspection step, confirmation is made by means and mechanical judgment is made by an automatic inspection machine consisting of visual or optical means. Therefore, the method according to the present invention does not use a conventional mechanical device such as a pin gauge, and is a method of optically determining a deviation of a determination pattern. Therefore, the determination is digital, and a margin of the determination itself is unnecessary. Thus, the flexible printed wiring board and the reinforcing plate for component mounting can be bonded with high precision. As a result, the present invention takes measures against the above-described C as a factor of the conventional tolerance and the removal of the margin at the time of the conventional pin gauge determination.

[0030]

1 to 5 are views showing a flexible printed wiring board according to an embodiment of the present invention and a method for manufacturing the same.

FIG. 1 is a view showing a state in which a component mounting reinforcing plate is attached to one FPC, and FIG. 2 is an example in which a judgment mark is arranged at an ideal position with respect to a component mounting land. FIG. 3 is a diagram for explaining the operation of the determination hole, the determination pattern, and the determination mark. FIG. 4 is a diagram for explaining the pass / fail determination with respect to the bonding accuracy by the determination mark. It is a figure which shows the state which adhered to the component mounting reinforcing board to the connected FPC.

FIG. 1 shows one embodiment of a specification provided to a user in a state in which a component mounting reinforcing plate is bonded to one FPC (flexible printed wiring board), and the outer shape of the FPC is shown. Is about 130mm ×
The dimensions are about 110 mm × 0.25 mmt, and the outer shape of the component mounting reinforcing plate is about 150 mm × 130 mm × 0.1 mm.
It is about 8 mmt. Generally, the thickness of FPC is 0.1
mm to about 0.4 mm. A typical single-sided FPC has a thickness of about 0.14 mm, and a typical double-sided FPC has a thickness of about 0.25 mm. The thickness of a hard printed board (PWB) with copper foil used as a reinforcing plate for component mounting is about 0.5 mm to 1.5 mm. Therefore, the size of the flexible printed wiring board is characterized in that it is smaller than the size of the component mounting reinforcing plate, so that the flexible printed wiring board is securely held, the state of bonding is easily checked, and the positional accuracy is improved. Is assured.

Also, by using a hard printed board (PWB) having a copper foil on the outer surface as a component mounting reinforcing plate, the component mounting reinforcing plate can be formed by an etching method having the same pattern as a photo process or silk screen printing. It is possible to display the product number, the upper and lower position marks of the board, and memos, thereby facilitating management of the manufacturing process.

In FIG. 1, an FPC 1 is bonded on a component mounting reinforcing plate 2 made of PWB or the like. FP
C1 has three judgment patterns (3a, 3b, 3c) and 1
A plurality of component mounting lands 4 are formed. Further, one of the determination patterns 3a is arranged in the area of the component mounting land 4. Three corresponding determination holes (not shown because they are below the FPC) are formed in the corresponding component mounting reinforcing plate 2, and each of the determination holes is paired with a determination pattern on the FPC. Make up the mark. As described above, when three determination patterns are used, one is disposed in the vicinity of or in the area of the component mounting land, and contributes to the improvement of the accuracy of the positional relationship between the component mounting land and the electrode terminal. . In the case of one embodiment in which only one FPC is bonded to one reinforcing plate for component mounting, if there is only one determination mark, it is not possible to confirm the angle to be bonded. It is necessary to set individual judgment marks. Therefore, the other two determination patterns (3b and 3c in this case) are arranged at a position as far as possible from the component mounting land on the periphery of the FPC. In this embodiment, the three determination patterns (3a, 3b, 3c) form a substantially straight line.

The auxiliary material bonding member 5 for adjusting the thickness of the connector insertion portion protrudes from the surface of the FPC board, and has a height of about 0.2 mm to 0.4 mm. In addition, a jig pin insertion hole 6 used for positioning with the component mounting reinforcing plate is also shown on the FPC, but only an auxiliary function is performed in the present invention.

Further, a rigid printed board (PW) having a copper foil
A guide hole 7 for component mounting, solder printing, and the like, and a marker 8 indicating the direction of the substrate are formed on the reinforcing plate for component mounting using B), thereby facilitating confirmation of bonding with the FPC. ing.

Next, the judgment mark (including the judgment pattern and the judgment hole) arranged in the component mounting land will be described. FIG. 2 shows an embodiment in which the judgment mark is arranged at an ideal position with respect to the component mounting land, and the judgment mark 10 is arranged at a position substantially at the center (center of gravity) of the area of the component mounting land 4. This determination mark is located at a position substantially equidistant from the four electrode terminals 11 of the component mounting land. And, the closer this determination mark is to the vicinity of the component mounting land, the more the bonding accuracy between the FPC and the component mounting reinforcing plate can be improved. The judgment mark 10 is constituted by a pair of the judgment pattern 3a and the judgment hole 9, and in this case, the diameter of the judgment pattern 3a is set to be smaller than the diameter of the judgment hole 9 by about 0.1 mm × 2.

Next, a judgment pattern is provided on the flexible printed wiring board, while a judgment hole is provided on the reinforcing plate for component mounting, and the judgment mark paired with the judgment pattern and the judgment hole is used as an alignment mark for flexible printing. A method for manufacturing a flexible printed wiring board by bonding a wiring board and a reinforcing plate for component mounting will be described.

In FIG. 3A, the polyimide substrate 12
A copper foil layer serving as a conductor is formed on one or both sides of the FPC. The FPC 14 has a determination pattern 13 formed simultaneously with the formation of the circuit pattern of the FPC using a photo process and etching. There is. Reference numeral 15 denotes a component mounting reinforcing plate made of PWB or the like,
Reference numeral 16 denotes a determination hole formed by punching a mold. Reference numeral 17 denotes a light source for irradiating the judgment mark, and reference numeral 18 denotes a unit for observing the light. The light source 17 is based on a fluorescent lamp, an LED light emitting element, or natural light,
The observation means 18 is an optical device composed of the naked eye, a CCD, or an ITV (industrial television for inspection).

FIG. 3 (b) is a view of FIG. 3 (a) viewed from the observation means side, where P is the diameter of the judgment pattern 13 and Q
Is the diameter of the determination hole. The component mounting reinforcing plate 15 made of PWB or the like is optically opaque, the polyimide substrate 12 is yellow-brown and optically transparent or translucent, and the determination pattern 13 made of copper foil or the like is optically opaque. is there.
Therefore, in the transmitted light image observed at 18, a light ring 20 due to the region 19 shielded from PWB or the like and the determination pattern 13 shielded from copper foil or the like is observed. Light source 1
A similar transmitted light image can be observed even if the positional relationship between the observation unit 7 and the observation unit 18 is reversed.

Referring to FIG. 4 showing the transmitted light image observed next, the relationship between the light ring, the bonding accuracy of the flexible printed wiring board and the component mounting reinforcing plate will be described.

The criterion for this bonding accuracy is FPC
When a judgment mark composed of a pair of a judgment pattern formed on the top and a judgment hole formed on the component mounting reinforcing plate is irradiated with light from below, the entire shape of the judgment pattern is determined by the judgment hole. It is possible to confirm without being interrupted by the peripheral part. FIG. 4A shows a state in which a ring-shaped light ring 20 can be confirmed and the light has passed. FIG. 4 (b)
Indicates that the circle of light 20 is missing and has a crescent shape, indicating a rejected state.

Judgment pattern 1 according to the first embodiment
3 and the diameter Q of the determination hole 16 are QP
= 0.1 mm × 2, and FIG. 4 (a) is the acceptance criterion, so that it can be determined with an accuracy of tolerance ± 0.1 mm. Further, as the set value of the tolerance accuracy, a value other than the above-mentioned QP = about 0.1 mm × 2 (that is, ± 0.
1 mm), for example, about (0.05 to 0.15 mm) × 2, as a matter of course. The method according to the present invention does not use a mechanical device such as a conventional pin gauge, and is an optical method of determining whether or not to recognize a determination pattern. No margin is required.

When a fluorescent lamp, an LED light-emitting element (visible light or near-infrared light), or natural light is used as the light source 17 and an optical device such as a CCD or ITV is used as the observation means 18, this transmission is The amount of light received by the light wheel 20 by the light image becomes the lowest constant value when passing in FIG. 4A, and increases in proportion to the degree of rejection as shown in FIG. 4B. I do. When the determination pattern is completely shifted from the determination hole in position, the amount of received light naturally becomes zero. Therefore, the amount of received light is
The amount of received light can be digitized using the case of the pass of (a) as a unit 1, and the pass / fail of the bonding accuracy can be digitally processed. Using the digital signal from this optical observation means, a mechanical judgment can be made by an automatic inspection machine. As the near-infrared LED light emitting element of the light source 17, a GaAs light emitting element or a GaAlAs light emitting element can be used.

FIG. 5 shows an example of an embodiment in which judgment marks in specifications of specifications provided to a user in a state of being bonded to a component mounting reinforcing plate are arranged on FPCs connected to a plurality of FPCs.

In FIG. 5, the FPC 21 is bonded on a component mounting reinforcing plate 22 made of PWB or the like.
The FPC 21 has three FPCs (21a, 21b, 21).
c), and each individual FPC is provided with one determination pattern (23a, 23b, 23c) for each component mounting land (24a, 24b, 24).
It is formed in the region c). Although not shown, a corresponding determination hole is formed in the component mounting reinforcing plate 22, and it is natural that these determination patterns and the determination hole form a pair of determination marks.

The auxiliary material bonding member for adjusting the thickness of the connector insertion portion protrudes from the surface of the FPC board, and its height is about 0.2 to 0.4 mm. Escape holes (25a, 25b, 25
c) is formed. Also, the component mounting reinforcing plate 2
2, a guide hole 27 for component mounting, solder printing, and the like, and a marker 28 indicating the direction of the substrate are formed.

In the case of the embodiment shown in FIG. 5, only one judgment pattern is formed on one FPC, but since three FPCs are connected, As a result, the tolerance accuracy is secured by the three determination marks (including the determination pattern and the determination hole), and these three determination marks form a straight line. Therefore, even if only one judgment mark near the component mounting land is present, the number of judgment marks corresponding to the number of spelled FPCs when bonded to the component mounting reinforcing plate is present. It is possible to deal with only the judgment marks.

[0049]

As described above, according to the present invention, in a flexible printed wiring board having a structure in which a component mounting reinforcing plate is bonded to a flexible printed wiring board, a determination pattern is provided on the flexible printed wiring board. And a determination hole is provided on the component mounting reinforcing plate,
A design tolerance of bonding accuracy of ± 0.15 mm is achieved by bonding the flexible printed wiring board and the reinforcing plate for component mounting with the determination mark that pairs the determination pattern and the determination hole as the alignment mark. We were able to.

[0050]

[0051]

[0052]

That is , according to the method of manufacturing a flexible printed wiring board according to the first aspect of the present invention, the determination pattern is provided on the flexible printed wiring board and the determination hole is provided on the reinforcing plate for component mounting. By bonding the flexible printed circuit board and the reinforcing plate for component mounting with the judgment mark paired with the judgment hole as the alignment mark, a design tolerance with high bonding accuracy can be set.

According to the method of manufacturing a flexible printed wiring board according to the second aspect of the present invention, the judgment pattern provided on the flexible printed wiring board is formed at the same time as the formation of the circuit pattern, so that the bonding accuracy is high. Design tolerances can now be set.

According to the method of manufacturing a flexible printed wiring board according to the third aspect of the present invention, the judgment hole provided in the component mounting reinforcing plate is formed simultaneously with the component mounting guide hole by punching a die. This makes it possible to set a design tolerance with high bonding accuracy.

Further, according to the method of manufacturing a flexible printed wiring board according to the fourth aspect of the present invention, the determination pattern is provided on the flexible printed wiring board and the determination hole is provided on the reinforcing plate for component mounting. A flexible printed wiring board and a component mounting reinforcing plate are bonded to each other with a determination mark paired with the determination hole as the alignment mark, and a pass / fail is determined by a transmitted light image to set a design tolerance of high bonding accuracy. Now you can do it.

As described above, in the present invention, the FPC
By adding a judgment pattern using copper foil that is formed simultaneously with the component mounting land above, even if there is a variation in the position of the self-rest of the positioning jig pin insertion hole of the conventional method, position correction is performed while bonding. As in the prior art, a defect is determined only by the final inspection, and there is no decrease in the production efficiency due to a decrease in the traverse rate.

Further, since visual judgment or automatic recognition becomes possible, it is not necessary to use a pin gauge, and it is not necessary to manage the wear and deformation of the pin gauge.

Further, since the number of positions for setting the positioning jig pin insertion holes can be reduced, the die for processing the outer shape of the FPC and the reinforcing plate for component mounting can be simplified, and the lead time and cost for die preparation can be reduced. .

[Brief description of the drawings]

FIG. 1 is a plan view of a flexible printed wiring board according to an embodiment of the present invention.

FIG. 2 is a diagram in which a determination mark of a flexible printed wiring board according to an embodiment of the present invention is arranged at an ideal position with respect to a component mounting land.

FIG. 3 is an explanatory diagram of the action of a judgment hole, a judgment pattern, and a judgment mark of the flexible printed wiring board according to one embodiment of the present invention.

FIG. 4 is a diagram illustrating a transmitted light image of a judgment mark observed on the flexible printed wiring board according to the embodiment of the present invention.

FIG. 5 is a view showing a state in which a plurality of flexible printed circuit boards of one embodiment are connected to a component mounting reinforcing plate.

FIG. 6 is a plan view of a conventional flexible printed wiring board.

FIG. 7 is a plan view of a component mounting reinforcing plate corresponding to FIG. 6 of a conventional example.

FIG. 8 is a view showing a state of pasting a conventional flexible printed wiring board and a reinforcing plate for component mounting.

FIG. 9 is an enlarged view of the vicinity of a positioning jig pin insertion hole in laminating a conventional flexible printed wiring board and a component mounting reinforcing plate.

FIG. 10 is an explanatory view of a bonding accuracy of a conventional example, and is an explanatory view of a relationship between a component mounting land and a guide hole of a component mounting reinforcing plate.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 FPC 2 Reinforcement plate for component mounting made of PWB, etc. 3 Judgment pattern on FPC 1 4 Land for component mounting 5 Auxiliary adhesive member 5 for thickness adjustment etc. for connector insertion part 6 Jig pin insertion hole 7 On component mounting reinforcing plate 8 Guide hole for mounting components, solder printing, etc. 8 Marker indicating board orientation 9 Judgment hole 10 Judgment mark 11 Electrode terminal of component mounting land 12 Polyimide base material 13 Judgment pattern 14 FPC 15 Component mounting made of PWB, etc. Reinforcement plate 16 Judgment hole formed by punching out mold 17 Light source for irradiating judgment mark 18 Observation means of judgment mark 19 Area shielded from PWB etc. 20 Ring of light 21 Three connected FPCs (21a) , 21b, 2
1c) 22 Reinforcement plate for component mounting made of PWB or the like 23 One determination pattern for each individual FPC (23
a, 23b, 23c) 24 Land for component mounting (24a, 24b, 24c) 25 Relief hole (25a, 25) for reinforcing plate 22 for component mounting
b, 25c) 27 Guide hole for component mounting, solder printing, etc. 28 Marker indicating substrate orientation P Diameter of determination pattern 13 Q Diameter of determination hole

Claims (4)

(57) [Claims] 1. A method of manufacturing by bonding a component mounting reinforcing plate to a flexible printed wiring board, wherein a determination pattern is provided on the flexible printed wiring board and a determination hole is provided on the component mounting reinforcing board. A method of manufacturing a flexible printed wiring board, comprising: bonding a flexible printed wiring board and a component mounting reinforcing plate to each other with a determination mark having a pair of a determination pattern and the determination hole as an alignment mark. 2. A method of manufacturing a flexible printed wiring board according to claim 1, wherein said judgment pattern provided on a flexible printed wiring board is characterized in that it is formed simultaneously with the circuit pattern formed. 3. A method of manufacturing a flexible printed wiring board according to claim 1, wherein said determination holes provided in the component mounting reinforcing plate is formed simultaneously with the component mounting guide holes by punching mold. 4. A flexible printed wiring board and a component mounting reinforcing plate, wherein a judgment pattern on the flexible printed wiring board and a judgment hole on the component mounting reinforcing plate are paired as a judgment mark. in the manufacturing method of match paste the flexible printed wiring board manufacturing method of claim 1, wherein the determining the quality by transmitted light image determination mark.