JP3307280B2 - Laser processing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser processing apparatus for irradiating a laser beam spot to cut or drill a workpiece, and more particularly, to a laser beam output upward and a laser The present invention relates to a laser processing device surrounded by a suction port of a processing atmosphere.

[0002]

2. Description of the Related Art In a laser processing apparatus for irradiating a thin film having a thickness of several μm or less with a laser beam to perform laser processing such as removal, cutting, or drilling of the thin film, the laser beam is emitted downward (in the direction of gravity). If the processing surface is arranged facing upward, the processing dust is scattered around the processing position at the time of processing, and often damages the thin film such as projections and pinholes.

In order to avoid this, laser light is emitted upward from the laser light emitting section, and the processing surface of the workpiece is arranged downward so that processing dust does not accumulate on the processing surface.
FIG. 4 is a cross-sectional view schematically showing a main part of the upward-emission laser processing apparatus. Condensing lens 11 of laser light emitting unit 1
The laser light L focused to one point by the
Focus on. Arrows indicate the relative movement between the workpiece 41 and the laser beam emitting unit 1. But in this case,
Processing dust generated at the time of laser processing accumulates or adheres to the output lens 11 of the laser light output unit 1 and substantially lowers the light transmittance of the output lens, that is, lowers the laser output and causes processing defects. Become. In addition, it may cause damage to the exit lens.

[0004] As a countermeasure, a protective cover through which laser light can pass is disposed outside the emission lens in parallel with the surface of the emission lens to prevent processing dust from accumulating on the lens, and at the same time, around the laser emission part. Then, the processing atmosphere was sucked by being surrounded by the suction port of the suction machine, and the processing dust was removed at the same time. 5A and 5B show a main part of a laser emission unit having a conventional protective cover and a suction device, wherein FIG. 5A is a plan view and FIG. 5B is a cross-sectional view taken along the line AA in FIG. A protective cover 12 covers the exit lens 11, and a suction duct 21 surrounds the protective cover 12.
Are enclosed. The processing atmosphere is sucked from the suction port 22. Arrows X and Y are coordinate axes indicating the direction of relative movement between the workpiece and the laser beam emitting unit.

[0005]

Conventionally, the suction port has been arranged so as to surround the laser beam emitting portion, and has been uniformly sucked. Therefore, when laser processing is performed while continuously moving the laser processing position, the laser light emitting portion is relatively moved in the processing direction with respect to the workpiece, so that the laser light emitting portion is located on the upper side in the processing direction from the processing position ( In the following, the suction at the upper side) sucks down the processing dust falling on the protective cover, and the processing dust accumulates and adheres to the protective cover.

[0006] In this way, the processing dust adhered to the lens protective cover is opaque to the laser light or scatters the laser light, causing a decrease in the output of the laser light, affecting the laser processing quality or making processing impossible. Had been done. Also, in a laser processing apparatus having an observation optical system for observing a processed part coaxially with the laser processing optical system, illumination light illuminating the observation unit adheres to the lens protection cover or the emission lens similarly to the laser processing optical system. It is obstructed by the processed dust and reduces the amount of light incident on a detector such as a camera, resulting in erroneous observation.

In particular, when the processing position is specified using this observation optical system, the detection level of the light amount changes due to the decrease in the incident light amount due to the attachment of the processing dust, and the processing positioning accuracy is lowered. In view of the above problems, an object of the present invention is to provide a laser processing apparatus capable of performing laser processing constantly without affecting the laser output and the observation optical system due to processing dust.

[0008]

In order to achieve the above object, a laser beam emitting section for upwardly emitting a laser beam passing through a protective cover surrounded by a suction port of a processing atmosphere, and a workpiece. A processing stage for holding the surface to be processed downward with respect to the laser light emitting portion, and an XY drive device for moving a relative position between the laser light emitting portion and the processing stage in a horizontal plane, In a laser processing apparatus that laser-processes a surface to be processed while changing processing atmosphere and suctioning processing dust together with a processing atmosphere, at least the suction port is divided into a plurality of portions, and a processing direction of the laser light emitting unit with respect to the processing stage. And a controller that controls the suction port on the rear side of the device to operate.

Preferably, the laser beam emitting section includes a wiper for removing processing dust accumulated on the protective cover.
The wiper may include a cloth that directly contacts the protective cover, means for sequentially feeding out a new portion of the cloth, and means for causing the cloth to rub the protective cover.

It is preferable that an optical system for detecting the level of light transmission due to processing dust on the protective cover be provided, and a signal corresponding to the level of light transmission output from the optical system be used as an operation start signal of the wiper. The optical system may include the laser light emitting unit and a laser light intensity measuring device provided on the processing stage, which measures the intensity of laser light passing through the protective cover used for laser processing.

The optical system includes a light source for emitting a light beam provided inside the protective cover of the laser light emitting section, and a mirror or a workpiece provided on the processing stage for reflecting the light beam. It is preferable to include a marker formed and a light intensity measuring device for measuring the light intensity of the reflected light beam.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS There are several methods for suctioning a processing atmosphere according to the present invention, and the main ones are as follows.
Can be classified into one. Reference numeral 1 denotes one suction machine and one suction duct, and a lid capable of opening and closing a suction port is divided, and each lid is individually controlled in opening and closing operations. 2 is a suction duct having one suction port. Are connected to one suction machine, and the opening and closing of the connection valve between the suction machine and each duct are individually controlled. 3 denotes one integrated suction port, suction duct and suction system of the suction machine are individually The suction operation of each suction system is individually controlled.

A controller for controlling the operation of the suction port receives an XY drive control signal or a drive direction signal from an XY drive device according to a program of the laser processing pattern, processes these signals and outputs the operation of the suction port corresponding to the processing direction. I do. Embodiment 1 FIG. 2 is a side view schematically showing a laser processing apparatus according to the present invention in which a laser beam emitting unit moves. Laser light emitting unit 1
Is fixed to the stage 31 of the XY-axis driving device 3,
It can move in any direction in the horizontal plane. The XY drive is controlled by an XY controller 32 to which a signal corresponding to the laser processing pattern has been input.

In this embodiment, the workpiece 4 is a flexible film substrate on which a thin film is formed. The film substrate 41 is a polyimide film. An aluminum thin film having a thickness of 0.2 μm is formed on the polyimide film by sputtering, and the film substrate 4 is wound around a roll 42. The film substrate 4 sent out from the roll 42 is fixed to the processing stage 41 during processing. After the processing, the film substrate 4 is wound around a roll 43.

The laser beam emitted from the laser beam emitting unit 1 is focused on the film substrate 4 fixed to the lower surface of the processing stage 41, and the aluminum thin film in that portion is removed. The laser light moves in the XY horizontal plane while being controlled on and off by the laser light control unit 13 to form a predetermined pattern on the aluminum thin film. Processing dust generated at the time of processing is sucked together with the atmospheric gas from a suction port provided around the laser light emitting unit 1 and is suctioned by a suction machine 23 provided outside the laser processing apparatus.

At the end of the processing stage 41, a head L1 of a laser output measuring device is provided.
The laser output can be measured when is moved below this. FIG. 1 shows a main part of a laser beam emitting unit having a wiper of a laser processing apparatus according to the present invention, and FIG.
Is a plan view, (b) is an AA sectional view in (a), and (c) is a side view of the wiper.

The suction ducts are suction ducts 21a, 21a.
The suction ports 22a, 22b, 22c and 22d are equally divided into four parts b, 21c and 21d and surround the protective cover 12. The suction and stop of each suction duct are independently controlled by the control unit 23. Arrows attached to the suction duct indicate the flow of the suctioned atmospheric gas (usually air) and the processing dust.

Then, the suction control is performed so that only the suction port in the rear direction with respect to the direction in which the laser beam emitting portion advances with respect to the surface to be processed (referred to as the processing direction) performs suction. For example, if the processing direction is the X direction, only the suction duct 21d, that is, only the suction port 22d sucks, and the other suction ducts do not suck. By doing so, it is possible to eliminate the recall of the processing dust generated when the processing dust generated during laser processing is sucked by the suction port located in the conventional processing direction, and to suppress the accumulation of the processing dust on the protective cover 12. did it.

It is not possible to completely prevent the accumulation of processing dust on the protective cover only by sucking the above-mentioned atmospheric gas. As a countermeasure, in the present invention, a wiper 15 for removing the processing dust accumulated on the protective cover is provided in the laser beam emitting unit. The main part of the wiper W is a cloth W1, which is supplied from a roll W2 and collected by a roll W4 pressed against the protective cover 12 by a roll W3. These are supported by the support W5. The support W5 moves along the rail W6, and the cloth W1 wipes off the processing dust on the protective cover 12.
Each time the wiper moves, the cloth W1 is taken up and a clean surface of the cloth W1 is supplied.

The timing for operating the wiper W is determined by optically detecting the amount of processing dust on the protective cover 12.
Each time a predetermined processing amount (for example, processing of one step of the film substrate) is completed, the laser light emitting unit 1 is moved below the head L1 so that the laser output can be measured. Then, when the decrease in the laser output was equal to or lower than a predetermined level, a signal was sent to the wiper W to operate it.

For example, when the laser output level is 95
By setting to%, the operation of the wiper is performed not after every step of the film substrate but after many steps of laser processing, and the progress of the laser processing step is hardly hindered, and the laser processing is performed. I was always able to do it stably. Embodiment 2 FIGS. 3A and 3B schematically show a laser processing apparatus according to the present invention in which a workpiece moves, wherein FIG. 3A is a side view and FIG. 3B is a cross-sectional view of an optical system. The workpiece 4 is the X-axis drive device 3 X
It is mounted on a processing stage 41 fixed to the Y stage 31 and can be moved in any direction in a horizontal plane.
Such an apparatus is effectively applied to a single wafer type patterning process.

The workpiece used in this embodiment is a glass substrate 42
A silver thin film having a thickness of 0.1 μm is formed on the glass substrate 42 by sputtering. This glass substrate 42 is vacuum-adsorbed and fixed to the processing stage 41. The laser beam emitting unit 1 is the same as in the first embodiment, and performs the same operation as the first embodiment. This embodiment is different from the first embodiment in the method of detecting the amount of processing dust on the protective cover. A light source L2 and a photodetector L3 are provided inside the protective cover of the laser light emitting unit 1, and the light beam LB emitted from the light source L2 is
The light is reflected by the light reflector L4 on the second side and returns to the light detector L3. The light detector detects the light intensity. The light reflector L4 may be mounted or formed on the workpiece 42 or may be provided on the processing stage 41. Since the light detection optical system has a different wavelength from the processing laser light, a laser optical system may be used.

On the glass substrate, a marker which is a metal (in this case, silver) thin film is formed at a fixed position for each pitch of the processing pattern. Since the reflectance of the marker was high and constant, this marker was used as the light reflector L4.
Each time the processing of one substrate is completed, the glass substrate is moved so that the marker is positioned above the laser light emitting unit 1, the level of the reflected light from the marker is measured, and the amount of the processed dust is determined.

If the level of the reflected light is below a predetermined value,
Operate the wiper. For example, when the amount of light reflected by a marker (normal value) is measured when the protective cover is not dirty, and the level due to the decrease in light transmittance of the protective cover is set to 95% of the normal value, the operation of the wiper is laser. The laser processing can be constantly performed with little hindrance to the progress of the processing step.

[0025]

According to the present invention, there is provided a laser beam emitting portion for upwardly emitting a laser beam passing through a protective cover surrounded by a suction port of a processing atmosphere, and a laser beam emitting portion for forming a laser beam on the workpiece surface of the workpiece. A processing stage that holds the light emitting unit downward, and an XY drive device that moves the relative position between the laser light emitting unit and the processing stage in a horizontal plane, and changes the relative position and also together with the processing atmosphere. In a laser processing apparatus that performs laser processing on a surface to be processed while sucking processing dust, at least the suction port is divided into a plurality of pieces, and the suction port on the rear side in the processing direction of the laser light emitting unit with respect to the processing stage is operated. To eliminate the recall of processing dust that occurs when suction is performed by a conventional suction port that is superior in the processing direction, and suppresses the accumulation of processing dust on the protective cover 12. I was able to.

Further, since the laser beam emitting section has a wiper for removing processing dust accumulated on the protective cover,
Processing dust slightly adhered to the protective cover is removed, the light transmittance does not decrease, the laser output from the laser emitting unit does not decrease, and the position of the workpiece can be accurately specified. As a result, laser processing can always be performed well, and the yield is improved.

Further, since the light transmittance of the protective cover can be monitored, the wiper may be intermittently performed, and the efficiency of laser processing is improved.

[Brief description of the drawings]

FIGS. 1A and 1B show a main part of a laser beam emitting part of a laser processing apparatus according to the present invention, wherein FIG. 1A is a plan view, FIG. Side view of

FIG. 2 is a side view schematically showing a laser processing apparatus according to the present invention in which a laser beam emitting unit moves.

3A and 3B schematically show a laser processing apparatus according to the present invention in which a workpiece moves, wherein FIG. 3A is a side view, and FIG. 3B is a cross-sectional view of an optical system.

FIG. 4 is a cross-sectional view schematically showing a main part of an upward-emission laser processing apparatus.

5 (a) is a plan view, and FIG. 5 (b) is a cross-sectional view taken along the line AA in FIG.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 laser light emitting unit 11 condensing lens 12 protective cover 21 suction duct 21 a ... 21 d suction duct 22 suction port 22 a ... 22 d suction port 23 suction pump 3 XY drive device 31 XY stage 32 XY controller 41 processing stage 42 workpiece 43 Roll 44 Roll W Wiper W1 Cloth W2 Roll W3 Roll W4 Roll W5 Roll W6 Rail L1 Laser light intensity measuring device L2 Light source L3 Light intensity measuring device L4 Reflector LB Light beam

Claims (6)

(57) [Claims] 1. A laser beam emitting section for emitting a laser beam passing through a protective cover surrounded by a suction port of a processing atmosphere, and a laser beam emitting section upwardly, and a processing surface of a workpiece to the laser beam emitting section. It has a processing stage that holds it downward, and an XY drive device that moves the relative position between the laser beam emitting unit and the processing stage in a horizontal plane, while changing the relative position and sucking the processing dust together with the processing atmosphere. In a laser processing apparatus that performs laser processing on a surface to be processed, at least the suction port is divided into a plurality of pieces, and the suction port on the rear side in the processing direction of the laser light emitting unit with respect to the processing stage is controlled to operate. A laser processing apparatus, comprising: 2. A laser processing apparatus according to claim 1, wherein said laser beam emitting section includes a wiper for removing processing dust accumulated on said protective cover. 3. The wiper includes a cloth directly in contact with the protective cover, and means for sequentially feeding out a new part of the cloth.
3. The laser processing apparatus according to claim 2, further comprising means for rubbing the protective cover with the cloth. 4. An optical system for detecting a level of light transmission due to processing dust on the protective cover, wherein a signal corresponding to a level of light transmission output from the optical system is used as an operation start signal of the wiper. The laser processing apparatus according to claim 1, wherein 5. The optical system according to claim 1, wherein the optical system includes the laser light emitting unit and a laser light intensity measuring device provided on the processing stage for measuring the intensity of laser light passing through the protective cover used for laser processing. The laser processing apparatus according to claim 4, wherein: 6. An optical system comprising: a light source for emitting a light beam provided inside the protective cover of the laser beam emitting portion; and a mirror or a workpiece provided on the processing stage for reflecting the light beam. The laser processing apparatus according to claim 4, comprising a marker formed on the object and a light intensity measuring device for measuring the light intensity of the reflected light beam.