JP7165597B2 - LASER PROCESSING APPARATUS AND LASER PROCESSING METHOD - Google Patents

Description

The present invention relates to a laser processing apparatus and a laser processing method for drilling holes in a workpiece such as a printed circuit board using a laser pulse.

Conventionally, in a laser processing apparatus using a laser oscillator such as a carbon dioxide laser oscillator, for example, as disclosed in Patent Document 1, especially FIG. Based on this, the laser oscillator is caused to oscillate a laser pulse, and an AOM control unit using an acoustooptic device (hereinafter abbreviated as AOM) using a crystal such as germanium that generates a diffraction grating by ultrasonic waves is output from the laser oscillator. It is known to deflect the laser pulse in the working direction or in the non-working direction.

In the laser processing apparatus as described above, the intensity and pulse width of the laser pulse applied to the workpiece are controlled by the AOM according to control information based on the material and processing specifications of the workpiece. there is
The optical system from the laser oscillator to the workpiece is devised so that the laser pulse irradiated to the workpiece does not cause damage due to the diffracted light of the first order or later. In the case of a low resin layer, if the peak energy of the laser pulse is high, scratches may occur around the hole due to diffracted light of the first and subsequent orders, and the processing quality may deteriorate.
On the other hand, conventionally, burst processing is performed by irradiating multiple times with a laser pulse with a reduced peak energy to prevent deterioration of processing quality. There is a drawback that the processing efficiency deteriorates.

Japanese Patent Application Laid-Open No. 2017-51987

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to prevent deterioration of processing quality without lowering processing efficiency in laser processing in which laser pulses are used to drill holes in a workpiece such as a printed circuit board.

In order to solve the above problems, among the inventions disclosed in the present application, a typical laser processing apparatus includes a laser oscillator that oscillates a laser pulse, and a light deflector into which the laser pulse from the laser oscillator is incident. an optical deflection control unit for controlling the operation of the optical deflection unit; and an optical scanner into which the laser pulse emitted from the optical deflection unit is incident, which is processed data. In a laser processing apparatus comprising a device for driving to irradiate a laser pulse to a processing position on a workpiece according to It is characterized by having a first processing mode in which the optical deflection section is controlled so that the laser pulse is emitted from the optical deflection section only once.

In addition, a typical laser processing method disclosed in the present application emits a laser pulse from a laser oscillator to an optical deflection unit that can be emitted by changing the energy, and the laser pulse emitted from the optical deflection unit is subjected to processing data according to processing data. A laser processing method in which a laser pulse is emitted from an optical scanner that is driven to irradiate a processing position on a workpiece to process the workpiece, wherein the laser pulse is incident from the laser oscillator. The laser pulse that continues before and after the attenuation of is emitted from the light deflection unit only once for processing.

The typical features of the invention disclosed in the present application are as described above, but features not described here are applied to the embodiments described below, and are also included in the scope of claims. As shown.

Advantageous Effects of Invention According to the present invention, it is possible to prevent deterioration of processing quality without lowering processing efficiency in laser processing in which laser pulses are used to perforate a workpiece such as a printed circuit board.

1 is a block diagram of a laser processing apparatus according to an embodiment of the present invention; FIG. It is a timing chart of the laser processing apparatus which is one embodiment of the present invention. It is a timing chart of the laser processing apparatus which is one embodiment of the present invention. 2 is a diagram showing the contents of a control table in FIG. 1; FIG. 2 is a diagram showing the contents of a control table in FIG. 1; FIG.

FIG. 1 is a block diagram of a laser processing apparatus according to one embodiment of the present invention. Each constituent element and connection line are those considered to be necessary mainly for explaining this embodiment, and do not necessarily show everything necessary for the laser processing apparatus.
In FIG. 1, reference numeral 1 denotes a printed circuit board to be processed placed on a table (not shown), and a resin layer 1P is formed on its surface. 2 is a laser oscillator that oscillates a laser pulse L1, 3 is an AOM deflection unit that deflects each laser pulse L1 output from the laser oscillator 2 in two directions, ie, a processing direction and a non-processing direction using an AOM, and 4 is an AOM deflection. A galvanometer scanner 5 as an optical scanner that changes the laser irradiation position of the laser pulse L2 deflected in the processing direction in the unit 3 and is rotationally driven so as to irradiate the drilling position of the printed circuit board 1 according to the processing data. A condensing (Fθ) lens for irradiating a laser pulse from a galvanometer scanner 4 onto a drilling position of the printed circuit board 1, 6 is a damper for absorbing the laser pulse L3 deflected in the non-processing direction in the AOM deflector 3.

Reference numeral 7 denotes an overall control unit for controlling the operation of the entire apparatus, which contains a laser oscillation control unit for outputting a laser oscillation command signal S for instructing the oscillation and attenuation of the laser pulse L1 in the laser oscillator 2. 8, an AOM control unit 9 that outputs an AOM drive signal D for controlling the operation of the AOM deflection unit 3, and a galvano control unit 10 that outputs a galvano control signal G for controlling the drive operation of the galvano scanner 4. It is
The AOM drive signal D output from the AOM control section 9 is composed of an RF signal, the deflection angle of the AOM deflection section 3 is changed according to the frequency of this RF signal, and the emission energy is changed according to the amplitude level of this RF signal.
The overall control unit 7 has control functions other than those described here, and is also connected to blocks not shown. The overall control unit 7 is configured, for example, mainly by a program-controlled processing device, and each constituent element and connection line therein include logical ones. Also, part of each component may be provided separately from the overall control unit 7 .

This laser processing apparatus has two processing modes A and B with respect to extraction of the laser pulse L2 by the AOM deflector 3. FIG.
FIG. 2 is a timing chart when the laser pulse L1 is oscillated from the laser oscillator 2 in the machining mode A. As shown in FIG. In FIG. 2, when the galvanometer operation control signal G is turned off and the galvanometer scanner 4 stops at the target position and the positioning operation is completed, the laser oscillation command signal S is turned on and the laser pulse L1 is oscillated. , and the laser output of the laser oscillator 2 gradually increases. The laser oscillation command signal S is turned on for a predetermined time T1, and when the laser oscillation command signal S is turned off, the attenuation of the laser pulse L1 begins and the laser output gradually decreases.
After the time T2 from when the laser oscillation command signal S is turned on, the AOM drive signal D is turned on for a predetermined time T3, and the laser pulse L2 for processing is extracted once during the period until the attenuation of the laser pulse L1 begins. .
After a predetermined time T4 from when the laser oscillation command signal S is turned on, the galvanometer operation control signal G is turned on and the galvanometer scanner 4 starts the positioning operation toward the next target position.

The processing mode A, as in the conventional case, takes out the laser pulse L2 for processing once during the period until the laser pulse L1 starts to decay from the laser oscillator 2, and is suitable when the processing energy threshold is high.
On the other hand, FIG. 3 is a timing chart when the laser pulse L1 is oscillated from the laser oscillator 2 in the machining mode B. As shown in FIG.
Processing mode B differs from processing mode A in timing in that the AOM drive signal D is turned on for a predetermined time T6 after the time T5 after the laser oscillation command signal S is turned on, and the laser pulse L2 is extracted once. is extended as a period until after the attenuation of the laser pulse L1 starts, and the amplitude level V2 of the AOM drive signal D is made lower than the amplitude level V1 in the processing mode A to reduce the peak energy of the laser pulse L2. was lowered. This machining mode B is suitable when the threshold value of the machining energy is low.

Information for controlling the output start timing of the AOM drive signal D, the output time, the amplitude level of the RF signal that determines the output energy, etc. is stored in the storage unit 12 in the AOM control unit 9 as control tables 11 and 12. . The AOM control section 8 determines the output start timing, output time, amplitude level, etc. of the AOM driving signal D according to the control information in the control tables 11A and 11B.
Control tables 11A and 11B are for machining modes A and B, respectively.
FIG. 4 shows the contents of the control table 11A for machining mode A. As shown in FIG. For example, control menu No. When the AOM drive signal D is determined according to 1A, the AOM drive signal D is turned on for a predetermined time T31A after the time T21A after the laser oscillation command signal S is turned on, and the amplitude level of the AOM drive signal D is set to V11A. Therefore, the AOM deflector 3 operates in the processing mode A.

Also, FIG. 4 shows the contents of the control table 11B for machining mode B. As shown in FIG. For example, control menu No. When the AOM drive signal D is controlled according to 1B, the AOM drive signal D is turned on for a predetermined time T61B after the time T51B after the laser oscillation command signal S is turned on, and the amplitude level of the AOM drive signal D becomes V21A. Therefore, the AOM deflector 3 operates in the processing mode B.
Each piece of information in the control tables 11A and 11B is obtained through experiments, device adjustments, etc., and registered in advance so that the timing is optimal according to the material of the printed circuit board to be processed and the processing specifications. . Which control menu determines the AOM drive signal D is determined by one control menu in the control table 11A or 11B under the control of the overall control unit 7, based on the material and processing specifications of the printed circuit board to be processed. is selected by

According to the above embodiment, the conventional machining mode A with high peak energy can be used when machining with a high threshold value of machining energy, and the machining mode B with a low peak energy can be used when machining energy is low.
In particular, when processing a resin layer with a low threshold value for processing energy in processing mode B, one laser pulse L2 for processing is taken out in a long period before and after the attenuation of the laser pulse L1. As a result, the processing energy of the laser pulse L2 as a whole can be secured, and the peak energy of the laser pulse L2 can be reduced instead. can be used, and the processing quality can be improved.
In addition, in processing mode B, since the processing energy as a whole can be secured with one laser pulse L2 for processing, processing can be completed without increasing the number of times of irradiation, in other words, without reducing processing efficiency. Become.
Therefore, it is possible to obtain a convenient laser processing apparatus that can cope with a wide range of processing energy threshold values of a workpiece and can improve processing quality without reducing processing efficiency.

In the above embodiment, control tables 11A and 11B are provided for machining modes A and B, respectively, but control menus for machining modes A and B may be registered in one control table.
Also, in the above embodiment, the laser processing apparatus performs both the processing modes A and B, but it may be performed only in the processing mode B.

1: Printed circuit board 2: Laser oscillator 3: AOM deflection unit 4: Galvano scanner 5: Condensing (Fθ) lens 7: Damper 7: Overall control unit 8: Laser oscillation control unit 9: AOM control unit 10: Galvano control Units 11A and 11B: Control table 12: Storage unit

Claims (3)

A laser oscillator that oscillates a laser pulse, an optical deflector that receives the laser pulse from the laser oscillator and that can emit the laser pulse by changing energy, and an optical deflection control that controls the operation of the optical deflector. and an optical scanner into which the laser pulse emitted from the optical deflection unit is incident, which is driven to irradiate the laser pulse to the machining position on the workpiece according to the machining data. In the first aspect, the optical deflection control unit controls the optical deflection unit so that the optical deflection unit emits only one laser pulse that continues before and after attenuation of the laser pulse incident from the laser oscillator. has a machining mode,
a second processing mode in which the optical deflection control unit controls the optical deflection unit so that the optical deflection unit emits a laser pulse only once in a period before the laser pulse emitted from the laser oscillator is attenuated; and the optical deflection control section controls, in the first processing mode, the peak energy of the laser pulse emitted from the optical deflection section to be equal to that of the laser pulse emitted from the optical deflection section in the second processing mode. A laser processing apparatus , wherein the light deflector is controlled so that the energy becomes lower than the peak energy . 2. The laser processing apparatus according to claim 1, wherein the optical deflection control section has storage means for storing first control information and second control information for controlling the optical deflection control section, A laser processing apparatus, wherein the control unit is controlled by first control information in the first processing mode and by second control information in the second processing mode. A laser pulse from a laser oscillator is emitted to an optical deflection unit that can be emitted by changing the energy, and the laser pulse emitted from the optical deflection unit is driven to irradiate the laser pulse to the machining position on the workpiece according to the machining data. In the laser processing method in which the laser pulse is emitted from the laser oscillator to the optical scanner to process the workpiece, the laser pulse that continues before and after the attenuation of the laser pulse that is incident from the laser oscillator is applied only once. a step as a first processing mode in which processing is performed by emitting a laser pulse from the light deflection unit;
a step as a second processing mode for controlling the optical deflection unit to emit a laser pulse from the optical deflection unit only once in a period before the laser pulse emitted from the laser oscillator is attenuated;
In the first processing mode, the light is adjusted so that the peak energy of the laser pulse emitted from the optical deflection unit is lower than the peak energy of the laser pulse emitted from the optical deflection unit in the second processing mode. A laser processing method , comprising a step of controlling a deflector .

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