JP3451481B2 - Laser processing apparatus and 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 processing apparatus and a laser processing method having a laser device for generating pulsed laser light and having a detecting means for detecting the energy value of each pulse.

[0002]

2. Description of the Related Art Various types of laser devices for generating pulsed laser light are provided. inside that,
In particular, a YAG laser device or a YLF laser device is used as a laser device used for making a hole in a plate member such as a printed wiring board or a ceramic substrate or welding a metal plate.
Laser devices, CO ₂ laser devices, etc. are known.

In a laser processing apparatus using such a laser device, the processing is carried out while monitoring the energy state of the pulsed laser light for each processing portion for each pulse. This will be described with reference to FIG.

In FIG. 3, the pulsed laser light from the laser device 21 reaches the partially transmissive bending mirror 24 through the bending mirrors 22 and 23, where about 99 is obtained.
% Is a processed lens 25 that is reflected and is also called fθ lens
The work 26 is irradiated with the light. The work 26 is mounted on an XY stage 30 movable in the X-axis direction and the Y-axis direction. About 1% of the laser light transmitted through the bending mirror 24 is introduced into the energy monitor 27 and the energy value is detected for each pulse. The detected pulse energy value is sent to the energy comparison circuit 28. The energy comparison circuit 28 can arbitrarily change the threshold value according to the processing conditions, for example, the material and the processing thickness of the work 26, compares the detected pulse energy value with the threshold value, and detects the detected pulse. When the energy value is lower, a signal indicating it is output to the trigger pulse generator 29. Upon receiving this signal, the trigger pulse generator 29 outputs a trigger pulse to the laser device 21 to generate an additional pulse laser beam.

The above operation is explained by exemplifying concrete numerical values.
Reveal Pulse per machining area depending on machining conditions
The number of laser beams is determined. For example, 0.
With a pulsed laser beam having an energy value of 4 (J),
One shot per drilling (through hole formation) processing
It is assumed that pulsed laser light is emitted. Energy in the optical path
If there is no luge loss, the energy monitor 27
The normal detection value of pulse energy is 4 (mJ).
It In consideration of this, the threshold value V _SLAs
Is set to 2.5 (mJ). First hole
The energy of pulsed laser light is high in the drilling process.
Hold value V_SLAnd the hole is formed normally on the workpiece 26
It has been done.

In the second boring process, the energy value of the pulsed laser light is low due to the laser device 21,
If it falls below the threshold value V _SL , the hole formed in the work 26 does not become a through hole. The energy comparison circuit 28 detects that the pulse energy value has fallen below the threshold value V _SL and outputs a signal to the trigger pulse generator 29. Trigger pulse generator 2
Upon receiving this signal, 9 outputs a trigger pulse to the laser device 21. Upon receiving the trigger pulse, the laser device 21 outputs additional pulse laser light at the same cycle as the normal pulse laser light. As a result, a through hole that completely penetrates the work 26 is formed.

[0007]

However, in the above laser processing apparatus, it cannot be said that the processed portion is irradiated with the optimum energy value. This is, even if the pulse energy value is slightly below the threshold value V _SL, even in the case of significantly lower than the threshold value V _SL, is because the pulse laser beam to be added is 1 shot. This poses a problem in forming a hole in the printed wiring board, especially when a conductive pattern made of copper is formed on the lower surface side of the printed wiring board and the area corresponding to the conductive pattern is formed. That is, the pulse energy value is the threshold value V _SL.
Even if it is slightly lower than, the pulsed laser light is additionally emitted by one shot, so that the energy much larger than the optimum energy value for drilling may be input and the conductive pattern may be damaged.

[0008] Such a problem becomes remarkable as the number of pulsed laser beams applied to one processed portion increases. For example, assume that one processed portion is irradiated with 10 pulse laser beams, and 2 of them are irradiated.
This becomes remarkable when the energy value of the emitted pulsed laser light is slightly lower than the threshold value V _SL .

In addition to the above-mentioned problems, if all the 10 pulsed laser beams have energy values that are slightly above the threshold value, no additional pulsed laser beam is generated. In this case, the total energy value of 10 shots of the pulsed laser light, becomes considerably higher There value compared to the total energy value when 10 shots of the pulsed laser beam all having a normal energy value.

Therefore, an object of the present invention is to provide a laser processing apparatus and a processing method capable of always performing processing with optimum energy for each processing site.

[0011]

The present invention is provided by a control device in a laser processing apparatus having a laser device for generating pulsed laser light and having a detecting means for detecting the energy value of each pulse. The target energy value is calculated from the expected energy value per pulse and the number of pulses to be irradiated to one processed portion, and the energy value detected by the detecting means is received and integrated, and the integrated result is obtained. A trigger generator for outputting an oscillation trigger to the laser device until the target energy value is reached is provided.

In the laser processing method according to the present invention, the energy value of each pulse of the pulsed laser light generated in the laser device is detected by the detection means for detecting the energy value built in the laser device, and the processed portion is detected. The target energy value is calculated from the expected energy value per pulse and the number of pulses to be irradiated to one processed portion, and the energy value detected by the detecting means is calculated. It is characterized in that this is received and integrated, and the processed portion is irradiated with laser light until the integrated result reaches the target energy value.

According to the present invention, the energy value of each pulse of the pulsed laser light generated in the laser device is detected by the detection means for detecting the energy value built in the laser device, and the laser device is detected. On the other hand, in the trigger generation method of outputting a trigger for laser light oscillation, a target energy value is calculated from the expected energy value per pulse and the number of pulses to be irradiated to one processing site, and the target energy value is detected by the detection means. There is provided a trigger generation method of receiving an accumulated energy value, integrating the energy value, and outputting an oscillation trigger to the laser device until the integration result reaches the target energy value.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. 1 and 2 in the case of a laser processing apparatus using an excimer laser apparatus. The present invention focuses on the fact that an excimer laser device, among laser devices, has an energy converter for detecting the energy value of each pulse, originally in the laser device.
Such a laser device is, for example, an I manufactured by Lumonix, Inc.
NDEX800, PM800, and IPEX series excimer laser devices are known. And so far,
The energy converter described above is used to stabilize the energy value for each pulse laser shot.

On the other hand, in the present invention, the total amount of energy applied to one processing portion is monitored, and the trigger of the laser device is controlled so that this amount becomes constant.

In FIG. 1, the present excimer laser device is
The laser device 10, the trigger generation device 11 for controlling the oscillation thereof, and the laser device 10 have an energy value per shot of pulsed laser light (hereinafter, this is referred to as an expected energy value) and one processing. And a control device 12 for setting how many pulsed laser beams are applied to the part.

The trigger generator 11 calculates a target energy value from the expected energy value per pulse given by the controller 12 and the number of pulses to be applied to one machining site. The trigger generator 11 also starts the oscillation of the laser device 10, receives the energy value of each pulse detected by the energy converter 10-1 incorporated in the laser device 10, and integrates the energy value. Laser device 10 until the integrated result reaches the target energy value
A trigger for oscillation is output to. In the following, it is assumed that the plurality of processed parts are processed with the same target energy values.

Before the machining is started, the trigger generator 11 receives the expected energy value per pulse and the number of pulses to be irradiated to one machining site from the control device 12 as parameters by serial communication. The target energy value for one processed part is calculated. Next, the trigger generator 11 outputs a trigger for starting the oscillation operation to the laser device 10. continue,
When the laser beam is generated from the laser device 10 and the processing is started, the trigger generation device 11 receives the energy value of each pulse laser beam in the laser device 10 from the energy converter 10-1 as an analog signal. The trigger generator 11 integrates the energy value of each pulse that is continuously sent in real time, and compares the integration result with the target energy value. Then, the trigger output is stopped when the integration result reaches the target energy value.

As described above, in the present embodiment, since the energy values obtained by the actual measurement of each pulsed laser beam are integrated, it is assumed that 10 pulsed laser beams are radiated to one processed portion. Even if there is an abnormality such as the energy value of the two pulsed laser beams is low, the optimum energy can be applied to the processed portion. Such an effect becomes remarkable especially as the number of pulsed laser beams applied to one processed portion increases.

FIG. 2 shows signal waveforms at various parts for executing the above operation. In FIG. 2, when the trigger generation device 11 calculates the target energy value based on the parameter from the control device 12, the trigger generation device 11 starts the output of the trigger by the start signal. Then, when the integrated energy value reaches the target energy value, the output of the trigger is stopped. The integrated energy value is reset by the start signal generated next. The trigger output indicated by the broken line is a charge trigger when the interval between trigger outputs exceeds a certain time, and this charge trigger is not counted as the number of triggers.

Although the embodiments of the present invention have been described above on the assumption that the processing is performed with the same energy value for a plurality of processed parts, the present invention is not limited to this. Absent. That is, even if the energy value is different for each processing site in a plurality of processing sites, if a different parameter is set in the control device 12 in advance for each processing site, the trigger device 11 causes each processing site for each processing site based on this parameter. It is possible to generate a different trigger output for each processed portion by calculating the target energy value.

[0022]

As described above, according to the present invention, it is possible to provide a laser processing apparatus capable of always performing processing with optimum energy for each processing site.

[Brief description of drawings]

FIG. 1 is a diagram showing a schematic configuration of an excimer laser device according to the present invention.

FIG. 2 is a signal waveform diagram for explaining a trigger operation by the trigger generator shown in FIG.

FIG. 3 is a diagram showing a configuration of a conventional pulse monitor type laser processing apparatus.

[Explanation of symbols]

10, 21 Laser device 11 Trigger generator 12 Control device 22-24 Bending mirror 25 Processed lens 26 Work 27 Energy Monitor 28 Energy comparison circuit 29 Trigger pulse generator 30 XY stage

Claims (3)

(57) [Claims] 1. A laser processing apparatus having a laser device for generating pulsed laser light and further having a detecting means for detecting the energy value of each pulse, in an expected energy value per pulse given by a control device. The target energy value is calculated from the number of pulses to be irradiated to one processed portion, the energy value detected by the detection means is received and integrated, and the laser is used until the integrated result reaches the target energy value. A laser processing apparatus comprising a trigger generation device that outputs a trigger for oscillation to the device. 2. An energy value for each pulse of pulsed laser light generated in the laser device is detected by a detection means built in the laser device for detecting the energy value, and the processed portion is irradiated with the laser light. In the laser processing method, the target energy value is calculated from the expected energy value per pulse and the number of pulses to be irradiated to one processing site, and the energy value detected by the detection means is received and integrated. Then, a laser processing method of irradiating the processed portion with laser light until the integrated result reaches the target energy value. 3. An energy value for each pulse of pulsed laser light generated in the laser device is detected by a detection means for detecting the energy value built in the laser device, and laser light oscillation is performed for the laser device. In the trigger generation method for outputting a trigger for use, a target energy value is calculated from an expected energy value per pulse and the number of pulses to be irradiated to one processed portion, and the energy value detected by the detection means is calculated. A trigger generation method that receives and integrates this, and outputs a trigger for oscillation to the laser device until the integration result reaches the target energy value.