JP3180806B2 - Laser processing method - 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 drilling machine for printed circuit boards.

[0002]

2. Description of the Related Art A conventional technique will be described below. FIG. 6 shows an example of a conventional laser drilling machine. FIG.
In the figure, 101 is a laser oscillator, 102 is a collimator, 103 is a mask, 104 is a transfer lens, and 105 is a workpiece, for example, a resin substrate containing glass fiber.

Next, the operation of the conventional technique will be described. The laser beam output from the laser oscillator 101 is enlarged and reduced in beam diameter by a collimator 102 and a mask 103
Is irradiated. The irradiated laser light is partially shielded by the mask 103, and the laser light passes only through the central hole,
An image is formed on the workpiece 105 by the transfer lens 104. Therefore, the shape of the mask 103 is imaged and processed on the workpiece 105.

[0004]

However, in the above-mentioned conventional configuration, a short pulse (about 1 μS) of laser light is used in order to reduce the energy applied to the mask in order to prevent burning of the mask. When the material or the mask diameter changes, the glass fiber remains due to the difference in the energy transmittance or the processing threshold value, the processing bottom surface is damaged, and the processing quality cannot be maintained. Was.

An object of the present invention is to solve the above-mentioned conventional problems, and an object of the present invention is to provide a stable processing quality when laser drilling various kinds of substrate materials using masks having various diameters. I do.

[0006]

In order to achieve the above object, the present invention provides a laser oscillator for outputting a laser beam,
Between the laser oscillator and the workpiece processed by the laser beam
A mask disposed between the mask and the workpiece.
Transfer lens, the laser oscillator, and the mass
Laser processing device with two or more collimators between
And move one of the collimators onto the laser beam.
While moving the collimator in the optical axis direction.
A laser processing method having a step is provided.

[0007]

According to the above means, the collimator
Move one of the lasers over the laser beam and
Move the remeter in the optical axis direction to illuminate the mask.
Adjust the diameter of the beam to be emitted, and adjust the beam
Brightness and energy can be controlled, material change
And shape etc. of the inner wall of the machined hole due to the change of the mask diameter
Processing quality can be stabilized.

In addition, a gas laser with a 1 μS
Laser pulse waveform is unstable when near short pulse output
However, using the present invention, the laser pulse is relatively stable
For example, while maintaining the waveform around 10 μS
Control of the energy passing through the
Energy can be stabilized, and stable processing quality
Can be obtained.

Reference Example 1 Hereinafter, a reference example relating to the present invention will be described with reference to the drawings.

FIG. 1 shows a reference example of a laser processing apparatus and a processing method. In FIG. 1A, reference numeral 1 denotes a laser oscillator, and reference numerals 2 and 3 denote lenses constituting a collimator. In this embodiment, a Kepler-type collimator is formed. Reference numeral 2 denotes a fixed lens and reference numeral 3 denotes a movable lens. Reference numeral 4 denotes a mask, 5 denotes a transfer lens, 6 denotes a workpiece, 7 denotes a driving device for the movable lens 3, and 8 denotes a driver. FIG. 1B shows the state of laser light when the distance between the fixed lens 2 and the movable lens 3 is reduced, as an example of moving the movable lens 3.

Hereinafter, the operation of the reference example will be described. In this figure, a Kepler-type collimator is configured, and a fixed lens 2
It is possible to control the diameter of the beam irradiated on the mask 4 by changing the distance between the lens 4 and the movable lens 3.

As shown in FIG. 1B, the fixed lens 2
When the movable lens 3 is moved closer to the beam, the beam tends to spread to the diverging side. Conversely, when the beam is moved farther away, a beam that tends to converge is obtained, and the beam diameter applied to the mask 4 can be controlled. Since the diameter of the mask 4 is determined by the diameter required for processing, a beam diameter suitable for the mask diameter can be obtained.

FIG. 2 shows a luminance distribution of a single mode laser beam. As is clear from FIG. 2, the beam has a distribution in which the luminance is high at the center and the luminance decreases toward the periphery. Therefore, when the mask is irradiated with a laser beam having a beam diameter appropriate for the mask diameter, it is possible to control the brightness of the laser beam passing therethrough and the energy passing through the mask, and as a result, the shape and shape of the hole wall surface processed For example, a difference in processing quality due to a change in mask diameter or material can be reduced, and stable processing quality can be ensured.

The driving device 7 can save labor by controlling the position of the movable lens 3 in accordance with the driver 8 instructed by the controller.

Reference Example 2 Referring to FIG. 3, a reference example relating to the present invention will be described.
explain.

In FIG. 3A, reference numeral 11 denotes a laser oscillator, 12, 13, and 14 denote lenses constituting a collimator. Two sets of Kepler-type collimators in this embodiment are formed, and 12 is a fixed lens. Reference numerals 14 and 14 denote first and second movable lenses, respectively. The laser is incident on the second movable lens and irradiates the mask while converging. Reference numeral 15 denotes a mask, 16 denotes a transfer lens, 17 denotes a workpiece, 18 denotes a driving device for the movable lenses 13 and 14, and 19 denotes a driver.

FIG. 3B shows an example of moving the movable lenses 13 and 14 when the laser beam enters the first movable lens 13 and irradiates the mask while diverging. showed that.

The operation of the present embodiment will be described with reference to the drawings, taking a Kepler type collimator as an example. The distance between the fixed lens 12 and the first movable lens 13 and the second movable lens 14 is different so that when a laser beam is incident on the first movable lens 13 shown in FIG. Then, the mask 15 is irradiated. On the other hand,
When a laser beam is incident on the second movable lens 14 shown in FIG. 3A, the laser beam is adjusted to a convergent beam and is irradiated on the mask 15.

By switching between the two sets of collimators adjusted to different characteristics as described above, it is possible to control the diameter of the beam irradiated on the mask 4.

As is clear from FIG. 2, the beam has a distribution in which the luminance is high at the center and the luminance decreases toward the periphery. Therefore, when the mask is irradiated with a laser beam having a beam diameter appropriate for the mask diameter, it is possible to control the brightness of the laser beam passing therethrough and the energy passing through the mask, and as a result, the shape and shape of the hole wall surface processed For example, a difference in processing quality due to a change in mask diameter or material can be reduced, and stable processing quality can be ensured. In particular, in the case of a gas laser, the laser pulse waveform becomes unstable when a short pulse of about 1 μS is output. However, according to the present invention, the laser pulse passes through the mask while maintaining a relatively stable waveform of, for example, about 10 μS. Energy can be controlled, so that the energy reaching the machining point can be stabilized,
It is possible to obtain stable processing quality.

Further, the driving device 7 can save power by controlling the position of the movable lens 3 in accordance with the driver 8 instructed by the controller.

( Embodiment ) FIG. 4 shows an embodiment of the present invention .

In FIG. 4A, 21 is a laser oscillator, 22 and 23 are lenses constituting a first collimator,
Reference numerals 24 and 25 denote lenses constituting a second collimator. In the case of this example, two sets of Galileo collimators are configured. In this figure, a laser beam is incident on a Galileo collimator composed of 24 and 25 lenses, and irradiates the mask while diverging. 26 is a mask, 27 is a galvano scanner that scans a laser beam at a predetermined location, 28 is an f-Θ lens having a transfer lens function, 29 is a workpiece, 30 is a driving device for switching between the two sets of collimators, 31 Is a driving device that moves the collimator in the optical axis direction,
32 is a driver.

FIG. 4B shows the state of the laser beam when the laser beam enters the first movable lens 13 and irradiates the mask while converging, as an example of moving two sets of collimators. Indicated.

The operation of the present embodiment will now be described with reference to the drawings, taking a Galileo collimator as an example. The collimators are arranged so that the distance between the first collimator including the lenses 22 and 23 and the second collimator including the lenses 24 and 25 are different from each other. In the example shown in FIG. 4B, when a laser beam is incident on the first collimator, the laser beam is adjusted to a convergent beam and irradiated on the mask 26.

On the other hand, in the example shown in FIG. 4A, when a laser beam is incident on the second collimator, the laser beam is adjusted to a divergent beam and is irradiated on the mask 26.

By switching between the two sets of collimators adjusted to different characteristics as described above, and further moving each collimator in the optical axis direction by the driving device 31 moving in the optical axis direction, the beam diameter to be irradiated on the mask 26 is obtained. Can be controlled.

As is clear from FIG. 2, the beam has a distribution in which the luminance is high at the center and the luminance decreases toward the periphery. Therefore, when the mask is irradiated with a laser beam having an appropriate beam diameter with respect to the mask diameter, it is possible to control the brightness of the laser beam passing therethrough and the energy passing through the mask, and as a result, the shape and shape of the processed hole wall surface A difference in processing quality due to a change in mask diameter or material can be reduced, and stable processing quality can be secured.

In particular, in the case of a gas laser, the laser pulse waveform becomes unstable at the time of outputting a short pulse of about 1 μS. However, according to the present invention, while the laser pulse is relatively stable, for example, the waveform of about 10 μS is maintained. Since the energy passing through the mask can be controlled, the energy reaching the processing point can be stabilized, and stable processing quality can be obtained.

Further, a driving device 30 for switching between two sets of collimators and a driving device 31 for moving each collimator in the optical axis direction control the position of each collimator with respect to the mask 26 in accordance with a driver 32 commanded by a controller. Can save labor.

Reference Example 3 A reference example relating to the present invention will be described with reference to FIG.
explain.

In FIG. 5A, reference numeral 41 denotes a laser oscillator, reference numeral 42 denotes a fixed lens, reference numeral 43 denotes a first movable lens, and reference numeral 44 denotes a second movable lens. In this embodiment, two sets of Keplerian collimators are configured. I have. In this figure, the laser light is 4
The light is incident on a Kepler-type collimator composed of 2,44 lenses, and irradiates the mask while diverging. 45
Is a mask, 46 is a transfer lens, 47 is a workpiece, 48 is a driving device for switching the movable lens, 49 is a driving device for moving the movable lenses 43 and 44 in the optical axis direction, 50
Is a driver. FIG. 5B shows the state of the laser beam when the laser beam enters the first movable lens 43 and irradiates the mask while converging, as an example of moving the movable lens.

Next, the operation of this embodiment will be described with reference to the drawings, taking a Kepler type collimator as an example. First composed of a fixed lens 42 and a lens movable lens 43
The collimators are arranged such that the distance between the lenses differs between the second collimator including the collimator, the fixed lens 42, and the movable lens 44. In the example shown in FIG. 5B, when a laser beam is incident on the first collimator, the laser beam is adjusted to a convergent beam and irradiated on the mask 45. On the other hand, FIG.
In the example shown in (a), when a laser beam is incident on the second collimator, the beam is adjusted to a divergent beam and is irradiated on the mask 45.

By switching between the two sets of collimators adjusted to different characteristics as described above, and further moving each collimator in the optical axis direction by the driving device 49 for moving in the optical axis direction, the beam diameter to be irradiated on the mask 45 is obtained. Can be controlled.

As is apparent from FIG. 2, the beam has a distribution in which the luminance is high at the center and the luminance decreases toward the periphery. Therefore, when the mask is irradiated with a laser beam having an appropriate beam diameter with respect to the mask diameter, it is possible to control the brightness of the laser beam passing therethrough and the energy passing through the mask, and as a result, the shape and shape of the processed hole wall surface A difference in processing quality due to a change in mask diameter or material can be reduced, and stable processing quality can be secured.

In particular, in the case of a gas laser, the laser pulse waveform becomes unstable at the time of outputting a short pulse around 1 μS. However, when the present invention is used, the laser pulse is relatively stable while maintaining a waveform around 10 μS, for example. Since the energy passing through the mask can be controlled, the energy reaching the processing point can be stabilized, and stable processing quality can be obtained.

Further, a driving device 48 for switching between two sets of collimators and a driving device 49 for moving each collimator in the optical axis direction control the position of each collimator with respect to the mask 26 in accordance with a driver 50 commanded by a controller. Can save labor.

As described above, according to the present embodiment, the provision of the mechanism for switching the collimator or the position of the lens constituting the collimator and the control means including the driving device for the moving mechanism provide the material or the mask diameter. If the value changes, it is possible to solve the problems that the glass fiber remains due to the difference in the energy transmittance and the processing threshold value, the processing bottom surface is damaged, and the processing quality cannot be maintained.

[0039]

As described above, according to the present invention, by providing the moving mechanism or the switching mechanism in the collimator, the processing quality such as the form and shape of the processing wall surface can be ensured.
Furthermore, when a short pulse around 1 μS is output, which is typical of gas lasers, the laser pulse waveform can avoid unstable parts and maintain a stable waveform, for example, around 10 μS, while controlling the energy passing through the mask. And an excellent laser processing apparatus and a processing method capable of obtaining stable processing quality can be realized.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a first embodiment of the present invention.

FIG. 2 is a luminance distribution diagram of a laser beam in a radial direction in a single mode laser.

FIG. 3 is a configuration diagram showing a second embodiment of the present invention ;

FIG. 4 is a configuration diagram showing an embodiment of the present invention.

FIG. 5 is a block diagram showing a third embodiment of the present invention.

FIG. 6 is a configuration diagram showing a conventional laser processing apparatus.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 laser oscillator 2 fixed lens 3 movable lens 4 mask 5 transfer lens 6 workpiece 7 drive device for movable lens 3 8 driver 11 laser oscillator 12 fixed lens 13 first movable lens 14 second movable lens 15 mask 16 transfer lens 17 Workpiece 18 Driving device for the movable lenses 13 and 14 19 Driver 21 Laser oscillator 22, 23 First collimator 24, 25 Second collimator 26 Mask 27 Galvano scanner that scans laser light at a predetermined location 28 f-Θ Lens 29 Workpiece 30 Driving device for switching the two sets of collimators 31 Driving device for moving the collimator in the optical axis direction 32 Driver 41 Laser oscillator 42 Fixed lens 43 First movable lens 44 Second movable lens 45 Mask 46 Transfer lens 47 Processing 48 drive device 50 driver for moving the driving device 49 movable lenses 43 and 44 for switching the movable lens in the optical axis direction

Continuation of the front page (51) Int.Cl. ⁷ Identification symbol FI // B23K 101: 42 (56) References JP-A-9-85991 (JP, A) JP-A-4-327394 (JP, A) JP Hei 11-58054 (JP, A) JP-A 2-32390 (JP, U) JP-A 4-64481 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) B23K 26 / 00-26/073 G02B 27/09 H05K 3/00

Claims (1)

(57) [Claims] A laser oscillator for outputting a laser beam;
Between the laser oscillator and the workpiece processed by the laser beam
Placed between the mask and the workpiece
The transfer lens and the laser oscillator and the laser
Laser processing equipment with two or more collimators between disks
Position one of the collimators on the laser beam
Moving and moving the collimator in the optical axis direction
A laser processing method having steps .