JPH06170570A - Outer shape machining method and device of flexible printed circuit board - Google Patents

Abstract

PURPOSE:To machine the outer shape of a flexible printed circuit board with high precision and at high speed. CONSTITUTION:An outer shape of a flexible printed circuit board is machined by the abrasion machining without thermal damage by irradiating the laser beam which is in the urtraviolet zone with the oscillating wavelength being <=400nu, and continuously oscillated. A laser beam source 1 (algon ion laser) to oscillate the laser beam, and scanning means (galvano-scanners 2, 3) to move the irradiating position of the laser beam from this laser beam source to a work W along the outer shape machining line CL are provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for processing a wiring board after forming a conductor pattern on an insulating film into a predetermined outer shape in a flexible wiring board manufacturing process.

[0002]

2. Description of the Related Art A flexible wiring board is formed by forming a number of identical conductor patterns on a sheet-like board (insulating film) by using a processing technique such as wet etching.
Finally, the respective patterns are punched into a predetermined outer shape to obtain one independent wiring board. Further, conventionally, such outer shape processing is generally performed using a punching press.

[0003]

By the way, with the recent miniaturization and high integration of electronic devices, the miniaturization thereof is progressing more and more, and even in the flexible wiring board, the external processing accuracy is ± 50 μm. Alternatively, high precision of less than that is required. However, the punching accuracy is at most ± 100 μm in press working.
At present, it is difficult to meet such demands.

Further, in the future, electronic equipment will be further miniaturized, and along with this, the flexible wiring board itself will be further miniaturized, and the machining accuracy will become more severe. There is an increasing demand for the transition to new processing methods that replace the above.

The present invention has been made in view of such circumstances, and it is an object of the present invention to provide a novel processing method capable of processing the outer shape of a flexible wiring board with high precision and high speed, and such a processing apparatus. To aim.

[0006]

In order to achieve the above object, in the method of the present invention, the substrate to be processed is irradiated with laser light from a laser light source that continuously oscillates ultraviolet light having a wavelength of 400 nm or less. By moving the laser light irradiation position along a predetermined outer shape processing line, the outer shape of the substrate to be processed is processed.

Further, the apparatus of the present invention, as shown in FIG. 1 corresponding to the embodiment, has a table 5 for holding a substrate W to be processed.
A laser light source (argon ion laser) 1 that continuously oscillates ultraviolet light having a wavelength of 400 nm or less, and an optical system (for example, a galvano scanner) that guides the laser light L from the laser light source 1 to a substrate W to be processed on the table 5. 2 and 3 and the condenser lens 4 and the like, and the irradiation position of the laser beam L onto the substrate W to be processed are determined by moving the substrate W to be processed or at least one of beam scanning L of the laser beam to obtain a predetermined outer shape. It is characterized in that it is provided with scanning means for moving along the processing line CL, for example, galvano scanners 2 and 3.

[0008]

First, the outer shape of the flexible wiring board is usually limited to the insulating film which is the base body, and the material of the insulating film is polyimide or PET (polyethylene terephthalate). Organic films are used.

Here, the organic film such as polyimide is
There is an advantage that cutting can be performed by ablation processing using laser light in the ultraviolet region (wavelength of 400 nm or less), and the ablation processing is due to a photochemical reaction so that thermal damage is small.

Therefore, by applying such ablation processing by laser light to the outer shape processing of the flexible wiring board, it becomes possible to perform high-precision processing.
Moreover, since continuous wave laser light is used for the above-mentioned outer shape processing, the above-described high-precision processing can be performed at a relatively high processing speed.

[0011]

Embodiments of the method and the device of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of an embodiment of the present invention.

The laser oscillator 1 continuously oscillates ultraviolet light having a wavelength of 400 nm or less, and for example, an argon ion laser is used. Laser light L from this laser oscillator 1
Is guided onto the working table 5 by two galvano scanners 2 and 3. Further, a condenser lens 4 is arranged between the galvano scanner 3 and the processing table 5 in the latter stage, and the laser light L from the laser oscillator 1 is used for the work W placed on the processing table 5, that is, the outer shape processing. The light is focused on the flexible wiring board.

Each of the Galvano scanners 2 and 3 has a general structure composed of a rotary mirror and a drive motor thereof, and is driven by a control signal from a driver (not shown) based on a command from the control device 6. The laser light L from the laser oscillator 1 is beam-scanned in the two-dimensional direction (X-Y direction) by each drive, and moves on the outer shape processing line CL of the work W on the processing table 5 at a constant speed. .

Next, the operation of the embodiment of the present invention will be described together with the processing procedure. First, the work W is a long sheet-like one in which a large number of conductor patterns are successively formed,
For example, it is wound around a reel and the like work W
Are sequentially sent to the processing table 5 in steps.

Now, the work W sent to the processing table 5 is fixed on this table, and then the fixed work W is positioned. As a means for fixing the work, suction with air or a clamp with a pressing plate is adopted for the purpose of preventing positional deviation during processing. Further, the processing table 5 has a structure capable of moving X-Y- [theta] in order to position the work W. Further, in order to perform accurate positioning, a camera is installed and the table is processed by image processing. Try to control the movement.

After the above positioning is completed,
At the same time when the oscillation of the laser oscillator 1 is started, the driving of each of the two galvano scanners 2 and 3 is controlled to irradiate the work W with the laser light L, and the laser light irradiation position is set along the contour processing line CL. The workpiece W is cut by the above-described ablation process by moving the workpiece W by moving it. The width of the cutting groove at the time of the outer shape processing can be adjusted within a range of, for example, about 10 to 100 μm by adjusting the focal length or the aperture ratio of the condenser lens 4.

Here, in the present invention, the reason why the substrate is cut using laser light in the ultraviolet region continuously oscillated from an argon ion laser or the like will be described below. First, as a laser used for this type of cutting (outer shape processing), there is, for example, a carbon dioxide gas laser or a YAG laser (fundamental wave). When laser light from these laser oscillators is used for processing an organic insulating film, Since the wavelength of the laser light is in the infrared region, the processing proceeds by a thermal reaction, so that the cut portion is thermally damaged, and the accuracy and appearance of the cut surface are extremely deteriorated.

On the other hand, there is an excimer laser as a laser capable of performing ablation processing without such thermal damage. This laser is pulse oscillation, and even if the excimer has a repetition frequency of 300 Hz, for example, one pulse of laser emission is generated. The time (pulse width) is extremely short, about several tens of nanoseconds, and the time during which the laser light is actually emitted is only several tens of microseconds per second. When applied to cutting processing, the cutting efficiency is poor and the processing speed is far below that of processing using laser light continuously oscillated by an argon ion laser or the like.

Therefore, in consideration of the above points, in the present invention, continuous wave laser light having an oscillation wavelength of 400 nm or less in the ultraviolet region is used for the outer shape processing of the flexible wiring board. Lasers that continuously oscillate laser light that can be ablated include argon ion lasers, krypton ion lasers, helium cadmium lasers, and the like, and even YAG lasers have a wavelength shorter than the fundamental wave. Although laser light having a wavelength (third or fourth harmonic) or the like can be used, it is preferable to use an argon ion laser in light of the output intensity of the laser light.

Further, in the above-mentioned embodiments of the present invention, the work to be processed is such that the insulating film forming the flexible wiring board is an organic film such as polyimide or PET, and the metal foil which is a conductor is attached to the organic film by epoxy. Alternatively, a wiring board bonded with an acrylic adhesive or a wiring board composed only of metal foil and polyimide (or PET, etc.) without using such an adhesive is used. What was said
In some cases, the processing speed and processing accuracy of the adhesive are inferior to that of polyimide. Therefore, especially for the purpose of high accuracy, high density and miniaturization, the insulating film is composed of only polyimide, as in the latter case described above. It is preferable to use the flexible printed circuit board as a work.

Further, during the ablation process, there is a case where carbon adheres to the peripheral part of the processed part, and a process of removing the carbon before proceeding to the next process is required, but helium or oxygen gas is processed during the process. This carbon adhesion can be prevented by blowing such as an assist gas. In particular, oxygen gas is particularly preferable because it has a large effect of preventing carbon from adhering and also has a Fukuji effect that the processing speed is increased.

In the above embodiment, the beam scanning of the laser beam is performed by the galvano scanner, but the beam scanning means may be another optical deflector such as a polygon mirror.

Further, in the above embodiments, the present invention is applied to the case where the long sheet-like works W are sequentially and continuously processed, but the present invention is not limited to this.
The present invention can be applied to the case where the work is divided into conductor patterns in advance and the divided sheets are sequentially processed. Further, when the divided work is processed in this way, for example, as shown in FIG. 2, the laser light from the laser oscillator 1 is applied to the half mirrors 20a and 2a.
If the structure is such that the divided sheets WS .. WS are irradiated with the respective divided laser beams after dividing by 0b, batch processing such as simultaneous processing of a plurality of sheets becomes possible, and processing efficiency is improved. Can be significantly improved.

FIG. 3 is a block diagram of another embodiment of the present invention. This example is different from the previous examples in that the beam scanning of the laser light is not performed and the irradiation position of the laser light on the work is moved by the movement of the work side.

That is, in this example, the machining table 35 holding the work W has a structure capable of XY-θ movement, and the movement of the machining table 35 is controlled by driving NC according to predetermined numerical data. A control device 36 is provided to move the machining table 35 to move the irradiation position of the laser light L onto the work W along a predetermined machining line when the outer shape of the work W is machined. In this example as well, even if the work W is a divided sheet or a long sheet for continuous processing, any processing is possible.

Here, when the flexible wiring board was actually processed using the apparatus having the configuration shown in FIG. 3 described above, good results were obtained, and a specific example thereof will be described below. .

First, a flexible wiring board having a copper foil surface patterned by a two-layer board having a polyimide thickness of 25 μm and a copper foil thickness of 18 μm is used as a work.
This work is placed on the processing table 35, fixed on the table by suction by air suction, and then image processing is performed while photographing the reference mark previously attached to the work, and the processing table 35 is based on the position information. The work was precisely controlled with respect to the optical axis of the laser light by controlling the drive of.

After the work is fixed and positioned, a laser oscillator (argon ion laser) is used.
At the same time when the oscillation of No. 1 was started, the machining table 35 was NC-controlled and moved according to the numerical data inputted in advance to perform the contour machining of the work. The oscillation conditions of the laser at this time are that the wavelength is 330 to 380 nm, the output intensity is about 1 W, the moving speed of the irradiation position of the laser beam on the work, that is, the processing speed is about 100 mm / s, and the assist gas Oxygen gas with a purity of 99.5% as 2
As a result of processing by spraying at a flow rate of (l / min), no thermal damage was observed on the processed work, that is, the cut surface of the polyimide part, and there was no carbon adhesion.
It was a good finish.

In addition to the structure of each of the above embodiments, if an optical system for guiding the laser light from the laser oscillator 1 to the work W is constituted by an optical fiber 40 as shown in FIG. The degree of freedom of the arrangement position of the oscillator 1 and the flexibility of processing can be improved.

[0030]

As described above, according to the method of the present invention, the flexible wiring board is irradiated with laser light of continuous oscillation in the ultraviolet region having an oscillation wavelength of 400 nm or less and ablation processing without thermal damage is performed. Since the outer shape of the wiring board is processed, the processing accuracy can be higher than that of the conventional press punching processing, and even if the wiring board is miniaturized with the miniaturization and high integration of electronic devices. Therefore, it is possible to realize highly accurate outer shape processing corresponding to it. Moreover, such highly accurate outer shape processing can be performed at a relatively high processing speed of, for example, about 100 mm / s.

Further, according to the apparatus of the present invention, since the apparatus adopting the ablation processing method using the above-mentioned laser light is adopted, for example, only by changing the soft surface of the beam scanning system of the laser light, it is possible to construct on the hardware. It is possible to achieve an effect that it is possible to deal with the outer shape processing of flexible wiring boards of various shapes without any particular change.

[Brief description of drawings]

FIG. 1 is a block diagram for explaining an embodiment of the present invention.

FIG. 2 is an explanatory diagram of a modified example of the embodiment.

FIG. 3 is a block diagram for explaining another embodiment of the present invention.

FIG. 4 is an explanatory view of a modified example of the embodiment of the present invention.

[Explanation of symbols]

 1 ・ ・ ・ ・ Laser oscillator (Argon ion laser) 2,3 ・ ・ ・ ・ ・ ・ Galvano scanner 4 ・ ・ ・ ・ Condensing lens 5 ・ ・ ・ ・ Processing table 6 ・ ・ ・ ・ ・ ・ Control device W ・ ・ ・ ・ Work ( Flexible wiring board)

Claims (2)

[Claims] 1. A method for processing the outer shape of a flexible wiring board having a conductor pattern formed on an insulating film, wherein laser light from a laser light source that continuously oscillates ultraviolet light having a wavelength of 400 nm or less is applied to a substrate to be processed. Irradiate,
A contour processing method for a flexible wiring board, characterized in that the laser light irradiation position is moved along a predetermined contour processing line. 2. A device for processing the outer shape of a flexible wiring board having a conductor pattern formed on an insulating film, the table holding a substrate to be processed, and a laser light source for continuously oscillating ultraviolet light having a wavelength of 400 nm or less. , An optical system that guides the laser light from the laser light source to the substrate to be processed on the table, and the irradiation position of the laser light to the substrate to be processed, the movement of the substrate to be processed or the beam scanning of the laser beam. An outer shape processing apparatus for a flexible wiring board, comprising a scanning means for moving along at least one predetermined outer shape processing line.