JP2020131247A - Laser beam machining apparatus and laser beam machining method - Google Patents

Abstract

To improve the machining quality without lowering the machining efficiency in laser beam machining in which a workpiece such as a printed circuit board is bored by using laser beam pulses.SOLUTION: A laser beam machining apparatus includes: a laser oscillator that oscillates laser beam pulses; a light deflection unit which the laser pulses from the laser oscillator enter and can emit laser pulses after changing the energy; a light deflection control unit that controls the operation of the light deflection unit; an optical scanner which the laser pulses emitted from the light deflection unit enter and is driven such that a machining position on a workpiece is projected with laser beam pulses according to machining data. The light deflection control unit has a first machining mode in which the light deflection unit is controlled so that a laser pulse which continues before and after the attenuation of the laser pulses incident from the laser oscillator is emitted from the light deflection unit only once.SELECTED DRAWING: Figure 1

Description

The present invention relates to a laser processing apparatus and a laser processing method for drilling or the like 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 gas laser oscillator, for example, as disclosed in FIG. 6 of Patent Document 1, the positioning operation by a galvano scanner for changing the laser irradiation position is completed. Based on this, a laser pulse is oscillated in the laser oscillator to generate a diffraction grating by ultrasonic waves. It is known that the laser pulse is deflected in the machining direction or the non-machining direction.

In the above-mentioned laser processing apparatus, the intensity and pulse width of the laser pulse applied to the workpiece are controlled by AOM based on the 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 applied to the workpiece does not cause scratches caused by the first and subsequent diffracted light, but the processing target has a threshold of processing energy. In the case of a low resin layer, if the peak energy of the laser pulse is high, scratches caused by the first and subsequent diffracted light may occur around the hole, and the processing quality may deteriorate.
On the other hand, conventionally, burst processing in which laser pulses with reduced peak energy are used multiple times is used to prevent deterioration of processing quality. However, in this method, irradiation is performed multiple times based on the oscillation cycle of the laser oscillator. There is a drawback that the processing efficiency deteriorates.

Japanese Unexamined Patent Publication No. 2017-51987

Therefore, an object of the present invention is to prevent deterioration of processing quality without deteriorating processing efficiency in laser processing in which a workpiece such as a printed circuit board is drilled by using a laser pulse.

In order to solve the above problems, among the inventions disclosed in the present application, in a typical laser processing apparatus, a laser oscillator that oscillates a laser pulse and a light deflection unit into which a laser pulse from the laser oscillator is incident. Processing data includes a device that can emit a laser pulse by changing the energy, a light deflection control unit that controls the operation of the light deflection unit, and an optical scanner that receives a laser pulse emitted from the light deflection unit. In a laser processing apparatus including a device that drives a processing position on a workpiece to irradiate a laser pulse according to the above, the light deflection control unit continues before and after the attenuation of the laser pulse incident from the laser oscillator. It is characterized by having a first processing mode in which the light deflection unit is controlled so that the laser pulse is emitted from the light deflection unit only once.

Further, in a typical laser processing method disclosed in the present application, a laser pulse from a laser oscillator is emitted to a light deflecting portion capable of emitting by changing energy, and the laser pulse emitted from the light deflecting portion is subjected to processing data. In a laser processing method in which the workpiece is processed by emitting light to an optical scanner that drives the processing position on the workpiece to irradiate a laser pulse, the laser pulse incident from the laser oscillator It is characterized in that a laser pulse that continues before and after the attenuation of the above is emitted from the light deflection portion only once to perform processing.

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

According to the present invention, in laser processing in which a workpiece such as a printed circuit board is drilled by using a laser pulse, deterioration of processing quality can be prevented without deteriorating processing efficiency.

It is a block diagram of the laser processing apparatus which becomes one Example of this invention. It is a timing chart of the laser processing apparatus which becomes one Example of this invention. It is a timing chart of the laser processing apparatus which becomes one Example of this invention. It is a figure which shows the contents of the control table in FIG. It is a figure which shows the contents of the control table in FIG.

FIG. 1 is a block diagram of a laser processing apparatus according to an embodiment of the present invention. Each component and connecting line mainly shows what is considered necessary for explaining this embodiment, and does not show all necessary for a laser processing apparatus.
In FIG. 1, reference numeral 1 denotes a printed circuit board to be processed, which is placed on a table (not shown), and a resin layer 1P is formed on the surface thereof. 2 is a laser oscillator that oscillates the laser pulse L1, 3 is an AOM deflection unit that deflects each of the laser pulses L1 output from the laser oscillator 2 in two ways, a machining direction and a non-machining direction, and 4 is an AOM deflection. The galvano 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 substrate 1 according to the processing data. The condensing (Fθ) lens that irradiates the laser pulse from the galvano scanner 4 to the drilling position of the printed substrate 1, 6 is a damper that absorbs the laser pulse L3 deflected in the non-processing direction in the AOM deflection unit 3.

Reference numeral 7 denotes an overall control unit for controlling the operation of the entire device, and inside the unit, laser oscillation control that outputs a laser oscillation command signal S for instructing oscillation and attenuation of the laser pulse L1 in the laser oscillator 2. AOM control unit 9 that outputs the AOM drive signal D for controlling the operation of the unit 8 and the AOM deflection unit 3, and the galvano control unit 10 that outputs the galvano control signal G for controlling the drive operation of the galvano scanner 4 are provided. Has been done.
The AOM drive signal D output from the AOM control unit 9 is composed of an RF signal, the deflection angle of the AOM deflection unit 3 is changed by the frequency of the RF signal, and the emission energy is changed by the amplitude level of the RF signal.
The overall control unit 7 has a control function other than that described here, and is also connected to a block (not shown). The overall control unit 7 is configured around a program control processing device, for example, and each component and connection line in the overall control unit 7 includes logical ones. Further, a 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 for extracting the laser pulse L2 by the AOM deflection unit 3.
FIG. 2 is a timing chart when the laser pulse L1 is oscillated from the laser oscillator 2 in the processing mode A. In FIG. 2, when the galvano operation control signal G is turned off and the galvano scanner 4 stops at the target position to complete the positioning operation, the laser oscillation command signal S is turned on and the laser pulse L1 is oscillated by the laser oscillator 2. Is commanded to, 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 laser pulse L1 starts to be attenuated and the laser output gradually decreases.
After the laser oscillation command signal S is turned on, the AOM drive signal D is turned on for a predetermined time T3 after the time T2, and the laser pulse L2 for processing is taken out once in the period until the laser pulse L1 starts to be attenuated. ..
After a predetermined time T4 after the laser oscillation command signal S is turned on, the galvano operation control signal G is turned on and the galvano scanner 4 starts the positioning operation toward the next target position.

The processing mode A takes out the laser pulse L2 for processing once in the period from the laser oscillator 2 until the attenuation of the laser pulse L1 starts, and is suitable when the threshold value of the processing energy 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 processing mode B.
The processing mode B differs from the processing mode A in terms of 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 one extraction period of the laser pulse L2 is performed. The time was extended as the period until the decay of the laser pulse L1 started, and the amplitude level V2 of the AOM drive signal D was made lower than the amplitude level V1 in the machining mode A to make the peak energy of the laser pulse L2. Is lowered. This machining mode B is suitable when the threshold value of machining energy is low.

Information for controlling the output start time of the AOM drive signal D, the output time, the amplitude level of the RF signal that determines the output energy, and the like is stored as control tables 11 and 12 in the storage unit 12 in the AOM control unit 9. .. The AOM control unit 8 determines the output start time, output time, amplitude level, etc. of the AOM drive signal D according to the control information in the control tables 11A and 11B.
The control tables 11A and 11B are for machining modes A and B, respectively.
FIG. 4 shows the contents of the control table 11A for the machining mode A. For example, control menu No. When determining the AOM drive signal D 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. The AOM deflection unit 3 operates in the machining mode A.

Further, FIG. 4 shows the contents of the control table 11B for the machining mode B. For example, control menu No. When controlling the AOM drive signal D 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 is set to V21A. The AOM deflection unit 3 operates in the machining mode B.
Each information in the control tables 11A and 11B shall be obtained by experiments, adjustment of equipment, etc. so as to be at the optimum timing according to the material and processing specifications of the printed circuit board to be processed, and shall be registered in advance. .. Then, 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. It is designed to be selected with.

According to the above embodiment, when machining with a high machining energy threshold value, the conventional machining mode A having a high peak energy can be performed, and when the machining energy is low, the machining mode B with a lowered peak energy can be performed.
In particular, when the resin layer having a low processing energy threshold is processed by the processing mode B, the laser pulse L2 for processing is taken out once 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, so that scratches caused by the first and subsequent diffracted light are not generated around the hole. It is possible to improve the processing quality.
Further, in the processing mode B, since the processing energy as a whole can be secured by one laser pulse L2 for processing, it is possible to complete the processing without increasing the number of irradiations, in other words, without lowering the processing efficiency. Become.
Therefore, it is possible to obtain a convenient laser processing apparatus that can respond widely according to the high and low thresholds of the processing energy of the workpiece and can improve the processing quality without lowering the processing efficiency.

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

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 (4)

A laser oscillator that oscillates a laser pulse, a light deflection unit that receives a laser pulse from the laser oscillator that can emit a laser pulse by changing the energy, and an optical deflection control that controls the operation of the light deflection unit. A laser processing apparatus including a unit and an optical scanner into which a laser pulse emitted from the light deflection unit is incident, which is driven so as to irradiate a processing position on a workpiece according to processing data. In the first, the light deflection control unit controls the light deflection control unit so that the laser pulse that continues before and after the attenuation of the laser pulse incident from the laser oscillator is emitted from the light deflection unit only once. A laser processing apparatus characterized by having a processing mode. In the laser processing apparatus according to claim 1, the light deflection control unit emits the laser pulse only once from the light deflection unit in the period before the attenuation of the laser pulse incident from the laser oscillator. The light deflection control unit has a second processing mode for controlling the unit, and in the first processing mode, the peak energy of the laser pulse emitted from the light deflection unit is the peak energy of the laser pulse in the second processing mode. A laser processing apparatus characterized in that the light deflection unit is controlled so as to be lower than the peak energy of a laser pulse emitted from the light deflection unit. In the laser processing apparatus according to claim 2, the light deflection control unit has a storage means for storing a first control information and a second control information for controlling the light deflection control unit, and the light deflection control unit has a storage means for storing the second control information. The laser processing apparatus is characterized in that the control unit is controlled by the first control information in the first processing mode and by the second control information in the second processing mode. The laser pulse from the laser oscillator is emitted to the light deflection part that can emit by changing the energy, and the laser pulse emitted from the light deflection part is driven so as to irradiate the processing position on the workpiece according to the processing data. In the laser processing method in which the workpiece is processed by emitting light to the optical scanner, the laser pulse that continues before and after the attenuation of the laser pulse incident from the laser oscillator is generated only once. A laser processing method characterized in that processing is performed by emitting a laser pulse from a light deflection portion.