JP4825716B2 - Method for manufacturing printed wiring board - Google Patents

Description

  The present invention relates to a printed wiring board manufacturing method, and more particularly, to an outer shape processing method in a printed wiring board manufacturing method.

When manufacturing a printed wiring board having a predetermined shape, a router bit as described in Patent Document 1 is usually used after a predetermined treatment is performed on a large-sized substrate that is a base material of the printed wiring board. A plurality of the printed wiring boards are obtained from one substrate by cutting the substrate by router processing.
Thus, the process of processing a large-sized substrate and obtaining a printed wiring board having a predetermined shape is generally referred to as an outline processing process.
JP 2004-202591 A

Here, the outline processing using the conventional general router bit as described in Patent Document 1 will be described with reference to FIG.
FIG. 5 is a plan view for explaining external shape processing using a conventional general router bit.

As shown in FIG. 5, the router bit 50 mainly includes a shank portion 51 and a blade portion 52.
Then, the router bit 50 is rotated at a high speed in a state where the shank portion 51 is held in a bit holding unit of a router processing machine (not shown), and then the blade 52 of the router bit 50 is moved in a predetermined state while being rotated at a high speed. The printed wiring is cut by passing the router bit 50 in a predetermined direction along the surface of the printed wiring board and cutting the large substrate with the blade portion 52. Get a board.

However, when the outer shape is processed using the router bit 50, a large amount of swarf is generated. If chips are attached to the externally processed printed wiring board, when the electronic component is mounted on the printed wiring board, the printed wiring board may cause poor connection between the printed wiring board and the electronic component. .
For this reason, normally, a router processing machine is provided with a suction means for quickly sucking and removing generated chips in the vicinity of the router bit. However, with this suction means alone, the chips can be completely removed. It is difficult.
In particular, in a printed wiring board used for an optical module such as a camera module, even a small amount of chips may cause deterioration of its optical characteristics. In order to remove swarf thoroughly, cleaning processing such as medium-pressure water cleaning and high-pressure water cleaning is performed after the outer shape processing.

Such cleaning treatment usually sprays water from both sides of the printed wiring board toward the board from the viewpoint of work efficiency, but the water hits both sides of the printed wiring board vertically. Although it is possible to completely remove the chips adhering to both surfaces of the board, water hits the end surface which is the cutting surface of the printed wiring board in parallel, and the water pressure is reduced at this end surface.
Therefore, it is usually handled by repeating the cleaning process, but repeating the cleaning process causes deterioration of productivity, and even if the cleaning process is repeated, it adheres to the end face of the printed wiring board. It is difficult to completely remove the chips, and an improvement is desired.

There is a press (punching) process as another outer shape processing method of the printed wiring board. Even in this pressing process, dust is generated when a large-sized substrate as a base material of the printed wiring board is punched.
Moreover, since the end surface of the printed wiring board formed by press work is a rougher surface compared with router processing, it becomes more difficult to completely remove the chips adhering to the end surface.

  Then, the subject which this invention tends to solve is providing the manufacturing method of the printed wiring board which can remove completely the chips adhering also in the end surface of a printed wiring board.

In order to solve the above problems, each invention of the present application has the following means.
1) In a printed wiring board manufacturing method for obtaining a printed wiring board having a predetermined external shape by performing external processing on a substrate (1) having a wiring pattern, the substrate is made of an insulating resin having a predetermined melting temperature. Including a slit portion forming step for forming the slit portion (10) on the substrate, and a heating step for heating the end surface of the slit portion to a temperature equal to or higher than the melting temperature after the slit portion forming step. It is a manufacturing method of the printed wiring board (20a) which becomes.
2) In a printed wiring board manufacturing method for obtaining a printed wiring board having a predetermined external shape by performing external processing on the substrate (1) having a wiring pattern, the substrate is made of an insulating resin having a predetermined melting temperature. A slit portion forming step for forming the slit portion (10) in the substrate, and after the slit portion forming step, the cylindrical portion (42) is rotated around its axis while the peripheral surface of the columnar portion is The end surface of the slit portion is brought into contact with the end surface of the slit portion by frictional heat generated by friction between the peripheral surface and the end surface when the cylindrical portion is moved along the slit portion while being pressed against the end surface of the slit portion. A printed wiring board (20a) manufacturing method characterized by comprising:
3) The method for producing a printed wiring board according to 2), wherein in the heating step, a diameter (R42) of the columnar portion is made larger than a length in a short direction of the slit portion.

  According to the present invention, there is an effect that it is possible to completely remove the chips adhering to the end face of the printed wiring board.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described with reference to FIGS.
1 to 4 are perspective views for explaining the first to fourth steps in the embodiment of the method for producing a printed wiring board of the present invention.
In the embodiment, a method for obtaining four printed wiring boards 20 from one wiring board 1 will be described.

<Example>
[First step] (see FIG. 1)
A core material 2, a plurality of first wiring pattern regions A 3, B 3, C 3, D 3 formed on the core material 2, and a core so as to cover these first wiring pattern regions A 3, B 3, C 3, D 3 A large-sized wiring board 1 having an insulating layer 4 formed on the material 2 and a plurality of second wiring pattern regions A5, B5, C5, D5 formed on the insulating layer 4 is produced.
The wiring board 1 can be manufactured by a known method.
The wiring board 1 serves as a base material for printed wiring boards 20a, 20b, 20c, and 20d to be described later, and a plurality of printed wiring boards 20a, 20b, 20c, and 20d can be obtained from the wiring board 1. it can.

The core material 2 is obtained by impregnating a sheet-like reinforcing material such as glass cloth with an insulating resin such as an epoxy resin and curing it.
The sheet-like reinforcing material has a function of improving the dimensional stability due to heat or the like of the printed wiring board and improving the rigidity of the printed wiring board.
In the example, the core material 2 was used by impregnating a glass cloth with an epoxy resin having a softening and melting temperature of 250 ° C. in a cured product state, and the thickness of the core material 2 was set to 0.4 mm.

The insulating layer 4 is obtained by applying an insulating resin such as an ink-like epoxy resin to the core material 2 by a known application method such as a screen printing method or a roll coating method, and curing it.
In the example, an epoxy resin having a softening and melting temperature in a cured product state of 250 ° C. was used, and the thickness of the insulating layer 4 was set to 50 μm.

  Each of the first wiring pattern areas A3, B3, C3, D3 and the second wiring pattern areas A5, B5, C5, D5 has a predetermined circuit wiring pattern, and the first wiring pattern area A3. , B3, C3, D3 and the second wiring pattern regions A5, B5, C5, D5 are formed in corresponding ranges and are electrically connected by vias (not shown).

[Second step] (See FIG. 2)
First, the router bit 30 having the shank part 31 and the blade part 32 is fixed to a rotating movable part of a router processing machine (not shown). Specifically, the shank portion 31 of the router bit 30 is fixed to the rotating movable portion of the router processing machine.
The router bit 30 can be a commercially available router bit used for general router processing.
In the embodiment, the diameter R32 of the blade 32 of the router bit 30 is 1.00 mm.

Next, after fixing the wiring board 1 manufactured in the first step to the router processing machine, the wiring board 1 is subjected to router processing based on a preset program.
Specifically, the router bit 30 is rotated at a high speed, and the router bit 30 is connected to the second wiring pattern areas A5, B5, C5, D5 (first wiring pattern areas A3, B3, C3, D3) of the wiring board 1. The wiring board 1 is passed through the wiring board 1 at a predetermined position in the gap between them, and further, the router bit 30 is moved along the surface of the wiring board 1 in a predetermined direction based on a preset program. To cut.

  In the embodiment, the second wiring pattern regions A5, B5, C5, and D5 (first wiring pattern regions A3, B3, C3, and D3) are arranged along the peripheral portion so that the uncut portion 11 is formed. A plurality of slits 10 were formed.

Since the router processing performed in the second step is the same as general router processing, the chips generated by the router processing adhere to both surfaces of the wiring board 1 and the end surface that is the cutting surface after the second step.
Here, the chips are chips of sheet-like reinforcing material such as glass cloth of the core material 2, chips of insulating resin of the core material 2, and insulating resin of the insulating layer 4 generated by the router processing. It is a general term for chips.

[Third step] (see FIG. 3)
After removing the router bit 30 used in the second step from the router processing machine, the blank 40 having the shank portion 41 and the columnar portion 42 is fixed in place of the router bit 30. Specifically, the shank portion 41 of the blank 40 is fixed to the router processing machine.
The cylindrical portion 42 in the blank 40 has a configuration in which the diameter R42 is larger than the width W10 of the slit 10 and the diameter R32 of the blade portion 32 of the router bit 30, and no cutting blade is provided on the peripheral surface thereof. ing.
Here, the blank material refers to a router bit having no cutting blade.
The blank material 40 is a rotating means that generates frictional heat with the end face of the wiring board 1.
In the example, the diameter R42 of the cylindrical portion 42 of the blank 40 was 1.03 mm.

Next, the blank material 40 is rotated so that the peripheral speed in the columnar portion 42 becomes a predetermined speed, and the blank material 40 is inserted into the slit 10 formed in the second step. In accordance with a preset program similar to the program used in the second step, the cylindrical part 42 is pressed against the end face of the wiring board 1 at the slit 10 part and the end face is traced. Move along the surface of 1.
In the Example, the peripheral speed in the cylindrical part 42 of the blank material 40 was 100 m / min to 200 m / min, and the moving speed of the blank material 40 was 30 m / min to 100 m / min.

Since the diameter R42 of the columnar portion 42 of the blank 40 is larger than the width W10 of the slit 10, when the columnar portion 42 is inserted into the slit 10, the columnar portion 42 is formed on the end surface of the wiring substrate 1 in the slit 10 portion. It will be in the pressed state.
Then, the blank material 40 is moved along the surface of the wiring board 1 so that the cylindrical part 42 traces the end face of the wiring board 1 in the slit 10 part, whereby the wiring in the cylindrical part 42 and the slit 10 part. Frictional heat is generated in the contact area with the end face of the substrate 1. Using this frictional heat, heating is performed so that the temperature of the wiring board 1 in the contact region is higher than the softening and melting temperature of the insulating resin of the core material 2 and the softening and melting temperature of the insulating resin of the insulating layer 4. By the above, the swarf adhering to the end face of the wiring board 1 in the slit 10 part, specifically, the swarf of the insulating resin of the core material 2 and the swarf of the insulating resin of the insulating layer 4 generated in the second step. While melting, each insulating resin of the core material 2 and the insulating layer 4 in the vicinity of the end surface including the end surface of the wiring board 1 is melted.
Moreover, after the blank material 40 passes, the insulating resin near the end surface including the melted chips and the end surface is cooled and integrated with the core material 2 and the insulating layer 4 on the end surface of the wiring board 1 in the slit 10 part. It becomes firmly fixed.
Further, the swarf of the sheet-like reinforcing material of the core material 2 generated in the second step is firmly integrated with the core material 2 and the insulating layer 4 together with the molten swarf and the insulating resin in the vicinity of the end surface including the end surface. It sticks to.
By this third step, the chips adhering to the end face of the wiring board 1 can be completely removed.

[Fourth step] (see FIG. 4)
The wiring substrate 1 that has undergone the above-described third step is repeatedly subjected to a known cleaning process such as medium-pressure water cleaning or high-pressure water cleaning as necessary to completely remove chips adhering to both surfaces of the wiring substrate 1. .
Thereafter, the uncut portion 11 of the wiring board 1 is removed by a well-known method to obtain a plurality of printed wiring boards 20a, 20b, 20c, and 20d.
The printed wiring board 20a has a first wiring pattern area A3 and a second wiring pattern area A5, and the printed wiring board 20b has a first wiring pattern area B3 and a second wiring pattern area B5. The board 20c has a first wiring pattern area C3 and a second wiring pattern area C5, and the printed wiring board 20d has a first wiring pattern area D3 and a second wiring pattern area D5.

  These printed wiring boards 20a, 20b, 20c, and 20d have wiring on the slit 10 portion that is difficult to remove by cleaning processing, in which chips adhering to both surfaces thereof are completely removed by cleaning processing such as medium pressure water cleaning and high pressure water cleaning. Chips adhering to the end faces of the substrate 1, that is, the respective end faces of the printed wiring boards 20a, 20b, 20c, and 20d are melted to these end faces and firmly fixed as a part of the printed wiring boards 20a, 20b, 20c, and 20d. ing.

Therefore, according to the method for manufacturing a printed wiring board of the present invention, when an electronic component is mounted on the printed wiring board, it is possible to prevent the occurrence of poor connection between the printed wiring board and the electronic component due to chips.
Moreover, according to the method for manufacturing a printed wiring board of the present invention, even when the printed wiring board manufactured by this manufacturing method is used in an optical module, it is possible to prevent deterioration of the optical characteristics.

  The embodiment of the present invention is not limited to the configuration and procedure described above, and it goes without saying that modifications may be made without departing from the scope of the present invention.

For example, in the examples, the softening and melting temperatures in the cured product state of the insulating resins of the core material 2 and the insulating layer 4 are 250 ° C., respectively, but are not limited thereto.
If each insulating resin has a different softening and melting temperature, the end face of the printed circuit board is melted by heating the end face of the printed wiring board to a temperature higher than the higher softening and melting temperature. Therefore, the same effects as in the embodiment can be obtained.

In the embodiment, insulating resin having a softening and melting temperature of 250 ° C. is used for each of the core material 2 and the insulating layer 4, the diameter of the blade portion 32 of the router bit 30 is 1.00 mm, and the cylindrical portion of the blank material 40 is used. The diameter of 42 is 1.03 mm, the peripheral speed in the cylindrical portion 42 of the blank material 40 is 100 m / min to 200 m / min, and the moving speed of the blank material 40 is 30 m / min to 100 m / min. It is not something.
That is, frictional heat is generated that heats the cut end face of the printed wiring board formed by the router bit 30 to a temperature higher than the softening melting temperature at which the insulating resin constituting the core material 2 and the insulating layer 4 melts. What is necessary is just to process according to conditions.

The frictional heat increases as the diameter of the cylindrical portion 42 of the blank 40 is larger than the diameter of the blade 32 of the router bit 30 and as the peripheral speed of the cylindrical portion 42 of the blank 40 increases. The lower the moving speed of 40, the larger the tendency. Therefore, by setting these conditions appropriately according to the softening and melting temperature of the insulating resin that constitutes the core material 2 and the insulating layer 4, the same effects as in the embodiment can be obtained. Can be obtained.
For example, as a result of the inventor's diligent experiment, the diameter of the cylindrical portion 42 of the blank 40 is made 0.02 mm to 0.04 mm (0.03 mm in the embodiment) larger than the diameter of the blade portion 32 of the router bit 30. Thus, it has been confirmed that the same effect as in the example can be obtained.

Further, in the embodiment, by making the diameter of the columnar portion 42 of the blank material 40 larger than the diameter of the blade portion 32 of the router bit 30, the insulation near the end surface including the chips adhering to the cutting end surface and the cutting end surface. However, the present invention is not limited to this.
For example, when the diameter of the cylindrical portion 42 of the blank 40 is the same as or smaller than the diameter of the blade 32 of the router bit 30, the cylindrical portion 42 of the blank 40 is formed on the cut end surface formed by the router bit 30. The same effect as in the embodiment can be obtained by moving the blank material 40 along the end face while pressing at a predetermined pressure.

  As another means for melting the chips adhering to the cutting end face and the insulating resin in the vicinity of the end face including the cutting end face, a heating means for heating the columnar portion 42 of the blank material 40 to a predetermined temperature may be provided.

  In the embodiment, the procedure for forming the slit 10 by router processing is used. However, the present invention is not limited to this, and the slit 10 may be formed by press processing instead of router processing.

  Moreover, although the Example demonstrated the method of obtaining the four printed wiring boards 20 from the one wiring board 1, it is not limited to this. Further, the thickness and configuration of the core material and the insulating layer are not limited to the examples.

It is a perspective view for demonstrating the 1st process in the Example of the manufacturing method of the printed wiring board of this invention. It is a perspective view for demonstrating the 2nd process in the Example of the manufacturing method of the printed wiring board of this invention. It is a perspective view for demonstrating the 3rd process in the Example of the manufacturing method of the printed wiring board of this invention. It is a perspective view for demonstrating the 4th process in the Example of the manufacturing method of the printed wiring board of this invention. It is a top view for demonstrating the shape of the conventional common router bit.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Wiring board, 2 Core material, 4 Insulating layer, 10 Slit, 11 Uncut part, 20a, 20b, 20c, 20d Printed wiring board, 30 Router bit, 31, 41 Shank part, 32, 42 Blade part, 40 Blank material A3, B3, C3, D3 Wiring pattern area, R32, R42 diameter, W10 width

Claims (3)

In the method of manufacturing a printed wiring board, by performing external processing on a substrate having a wiring pattern to obtain a printed wiring board having a predetermined external shape,
The substrate includes an insulating resin having a predetermined melting temperature, and a slit portion forming step of forming a slit portion in the substrate;
After the slit portion forming step, a heating step of heating the end face of the slit portion to a temperature equal to or higher than the melting temperature,
A method for producing a printed wiring board, comprising: In the method of manufacturing a printed wiring board, by performing external processing on a substrate having a wiring pattern to obtain a printed wiring board having a predetermined external shape,
The substrate includes an insulating resin having a predetermined melting temperature, and a slit portion forming step of forming a slit portion in the substrate;
After the slit portion forming step, while rotating the columnar portion around its axis, the peripheral surface of the columnar portion is brought into pressure contact with the end surface of the slit portion, and the columnar portion is moved along the slit portion. A heating step of heating the end surface to a temperature equal to or higher than the melting temperature by frictional heat generated by friction between the peripheral surface and the end surface during the movement;
A method for producing a printed wiring board, comprising: In the heating step,
3. The method of manufacturing a printed wiring board according to claim 2, wherein a diameter of the columnar portion is larger than a length of the slit portion in a short direction.

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