JP7125254B2 - LASER PROCESSING APPARATUS AND LASER PROCESSING METHOD - Google Patents

Description

The present invention relates to a laser processing apparatus and laser processing method for processing a substrate using a laser.

For example, when drilling a substrate in which a metal layer such as a copper foil layer is laminated on a resin layer, as disclosed in Patent Document 1, for example, one laser pulse oscillated from a laser oscillator causes the metal layer to be drilled. There is a method for shortening the processing time by taking out a plurality of processing laser pulses separately for processing and resin layer processing.
In this type of substrate, which consists of multiple layers of different materials, there are various kinds of materials and thicknesses of the metal layer and the resin layer. If it is not taken out at the right time, there is a problem that holes are drilled to an extra layer or the method of drilling holes is insufficient.

JP 2017-047471 A

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to extract, at appropriate timing, a processing laser pulse having appropriate energy from a single laser pulse emitted from a laser oscillator when processing a substrate composed of multiple layers of different materials. .

Among the inventions disclosed in the present application, a typical laser processing apparatus includes a laser oscillator that oscillates a laser pulse, and an acousto-optic modulator that splits the laser pulse output from the laser oscillator into a processing direction and a non-processing direction. and a branching operation controller for controlling the branching operation in the acoustooptic modulator, wherein the branching operation controller receives one laser pulse from the laser oscillator received by the acoustooptic modulator. A storage unit that controls the acousto-optic modulator so as to branch in the processing direction in a plurality of times, and registers branch control information for determining each branch timing and each branch output level, The branch operation control section is characterized by controlling the branch operation of the acousto-optic modulator based on the branch control information.

Further, among the inventions disclosed in the present application, a typical laser processing method includes inputting a laser pulse oscillated by a laser oscillator into an acousto-optic modulator for branching into a processing direction and a non-processing direction, In the laser processing method in which processing is performed by laser pulses branched in the processing direction, one laser pulse from the laser oscillator received by the acousto-optic modulator is divided into a plurality of times and branched in the processing direction. It is characterized in that branching control information for determining the branching timing and level of each branching output is stored in a storage unit, and the branching operation of the acousto-optic modulator is controlled based on the branching control information.

According to the present invention, when processing a substrate composed of a plurality of layers of different materials, it is possible to take out a plurality of processing laser pulses with appropriate energy at appropriate timing from one laser pulse emitted from a laser oscillator. This enables high-speed, high-quality processing.

1 is a timing chart of a laser drilling device according to an embodiment of the present invention; 1 is a block diagram of a laser drilling device according to an embodiment of the present invention; FIG. 3 shows the contents of control information for controlling the AOM drive unit registered in the AOM control unit in FIG. 2; FIG. 4 is a cross-sectional view for explaining the progress of processing by the laser drilling device according to one embodiment of the present invention;

FIG. 2 is a block diagram of a laser drilling device according to one embodiment of the present invention. Each component and connection line are shown as necessary mainly for explaining this embodiment, and do not show all necessary as a laser drilling device.
In FIG. 2, a substrate 1 to be drilled is placed on a table (not shown). 2 is a laser oscillator that oscillates a laser pulse L1, 3 is an acousto-optic modulator (hereinafter abbreviated as AOM) that splits the laser pulse L1 output from the laser oscillator 2 into a working direction and a non-working direction, and 4 is an AOM 3 in the working direction. It is a galvanometer scanner that irradiates a hole drilling position on the substrate 1 with a laser pulse L2 branched into two. This galvanometer scanner 4 scans the laser pulse L2 by rotating. A damper 5 absorbs the laser pulse L3 branched in the non-processing direction at the AOM 3. FIG.

Reference numeral 6 denotes an overall control section that controls the operation of the entire apparatus, and includes several elements. A laser oscillation control unit 7 outputs a laser oscillation command signal S for instructing the oscillation of each laser pulse L1 in the laser oscillator 2, and an AOM control unit 8 controls the operation of the AOM 3 via an AOM driving unit 9, which will be described later. , 9 is an AOM driving unit which receives control from the AOM control unit 8 and outputs an AOM driving signal D to the AOM 3, and 10 is a galvano control unit which outputs a galvano operation control signal G instructing the operation of the galvano scanner 4. . Some or all of these control units may be provided separately from the overall control unit 6 .
The AOM driving signal D output from the AOM driving section 9 is composed of an ultrasonic voltage signal, and the AOM 3 is turned on and off depending on whether or not this ultrasonic voltage signal is applied. It is changed according to the amplitude level of the voltage signal.

The overall control unit 6 has control functions other than those described here, and is also connected to blocks not shown. The overall control unit 6 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 6 .

FIG. 1 shows a timing chart of the laser drilling apparatus shown in FIG.
The galvano-operation control signal G is turned on to rotate the galvano-scanner 4 when drilling a hole at a new position, and is turned off to stop the galvano-scanner 4 . When the galvano operation control signal G is turned off, the laser oscillation command signal S is turned on for a predetermined time. starts the decay of the laser pulse L1.
When the laser oscillation command signal S is turned on, the AOM drive signal D is turned on for T1 time after t1 time, and the AOM drive signal D is turned on for T2 time after t2 time after the laser oscillation command signal S is turned on. During the time period when the AOM drive signal is on, the laser pulse L1 input to the AOM 3 is branched in the processing direction and applied to the galvanometer scanner 4 as a laser pulse L2. Further, during the time period when the AOM drive signal D is off, the laser pulse L1 input to the AOM 3 is branched in the non-machining direction and given to the damper 5 as the laser pulse L3.

FIG. 3 shows the contents of control information for controlling the AOM drive section 9 registered in advance in the storage section 11 within the AOM control section 8. As shown in FIG. In accordance with this control information, the AOM control unit 8 outputs an ultrasonic voltage signal having an amplitude level V1 of V1 for a period of time T1 in an interval A1 starting t1 time after the laser oscillation command signal S is turned on. In a section A2 starting after t2 time from turning on, an ultrasonic voltage signal with an amplitude level V2 of V2 is output from the AOM driving section 9 for a time T2. Here, the ultrasonic voltage signal output in the section A2 is set to have a shorter output time and a lower amplitude level than those output in the section A1.
Each data to be registered as control information in the storage unit 11 is experimentally obtained in advance so that the optimum energy at the optimum timing for the substrate to be processed is obtained.

FIGS. 4A and 4B are cross-sectional views for explaining the process of drilling holes in a substrate in which a metal layer is laminated on a resin layer, using the laser drilling apparatus described above. (b) shows the state during processing, and (c) shows the state after processing. In FIG. 3, 22 is a metal layer made of, for example, copper foil on the surface side of the substrate 1 to be drilled, 23 is a resin layer under the metal layer 22, and 24 is a copper foil under the resin layer 23. It is a metal layer that becomes

According to the laser drilling apparatus described above, as shown in FIG. 1, the AOM 3 outputs a laser pulse 2 with high energy in section A1, and outputs a laser pulse 2 with low energy in the next section A2. As a result, the metal layer 22 having a high processing energy threshold on the surface side of the substrate 1 is mainly processed in the section A1 as shown in FIG. 3B, and in the next section A2 as shown in FIG. Then, the resin layer 23 with a low processing energy threshold is mainly processed, and a hole 25 that finally reaches the metal layer 24 is formed.

According to the above embodiment, when the substrate 1 in which the metal layer 22 is laminated on the resin layer 23 is drilled, one laser pulse emitted from the laser oscillator 2 causes both the metal layer 22 and the resin layer 23 to be perforated. can be processed at once.
Furthermore, since the energy for processing the metal layer 22 and the resin layer 23 is adjusted to be optimal, the energy may be too large to process the metal layer 24, or the energy may be too small. Therefore, it is possible to prevent the resin layer 23 from being insufficiently drilled.
Therefore, high-speed and high-quality hole machining can be realized.

As described above, the present invention has been described mainly with reference to the examples, but the examples are examples for facilitating understanding of the present invention. Various modifications are possible. Accordingly, the invention is not limited to the examples.

For example, in the above embodiment, the number of layers to be drilled in the substrate 1 is two, and the section for turning on the AOM drive signal D is set to one corresponding to each layer, for a total of two. It may not be necessary, and the number of sections may be greater than that. This makes it possible to soften the impact on the resin layer 23 and to form a good quality hole in this area. Furthermore, the impact on the metal layer 24 can be suppressed.
Also, in the above embodiment, the case of drilling holes in a board in which the metal layers 22 and 24 are laminated on the upper and lower sides of the resin layer 23 has been described, but a laminated board made of other materials may also be used. For example, resin layer 23 may alternatively be a ceramic layer.

1: substrate, 2: laser oscillator, 3: AOM, 4: galvanometer scanner, 5: damper,
6: overall control unit, 7: laser oscillation control unit, 8: AOM control unit, 9: AOM driving unit,
10: Galvano control unit, 11: storage unit, 22, 24: metal layer, 23: resin layer,
25: hole, D: AOM drive signal, G: galvano operation control signal,
L1 to L3: laser pulse, S: laser oscillation command signal

Claims (3)

A laser oscillator that oscillates a laser pulse, an acousto-optic modulator that splits the laser pulse output from the laser oscillator into a processing direction and a non-processing direction, and a branching operation control that controls the branching operation in the acousto-optic modulator. In the laser processing apparatus comprising a section, the branching operation control section is controlled by an acousto-optic modulator drive signal divided into a plurality of sections at the rising edge of one laser pulse from the laser oscillator received by the acousto-optic modulator. A storage unit for controlling the acousto-optic modulator so as to direct it in one processing direction, and storing branch control information for determining each branch timing and each branch output level, wherein the branch operation control A laser processing apparatus, wherein the section controls the branching operation of the acoustooptic modulator based on the branch control information, and the acoustooptic modulator drive signal is composed of a plurality of ultrasonic voltage signals. A laser processing method in which a laser pulse oscillated by a laser oscillator is input to an acousto-optic modulator that branches in a processing direction and a non-processing direction, and processing is performed by the laser pulse that is branched in the processing direction in the acousto-optic modulator, Each branching timing and each branch for directing one processing direction by an acousto-optic modulator drive signal divided into a plurality of intervals at the rise of one laser pulse from the laser oscillator received by the acousto-optic modulator Branching control information for determining the output level is stored , the branching operation of the acoustooptic modulator is controlled based on the branching control information, and the acoustooptic modulator drive signal is generated from a plurality of ultrasonic voltage signals. A laser processing method characterized by: In the laser processing method according to claim 2, when processing a substrate composed of a plurality of layers of different materials, one laser pulse is branched in the processing direction the number of times corresponding to the number of layers to be processed. A laser processing method characterized by:

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