JP4873578B2 - Laser processing apparatus and method for determining processing conditions - Google Patents

Description

  The present invention relates to a laser processing apparatus and a processing condition determination method for performing laser processing on a plurality of processing points while moving an incident position of a pulse laser beam on a processing object.

  A general operation of a processing apparatus that performs laser processing by making a laser beam incident on a processing object from a pulse laser oscillator via a propagation optical system, a galvano scanner, and an fθ lens will be described. After the pulse laser beam is incident on one processing point, the galvano scanner is operated to move the incident position of the laser beam to the next processing point. After completing the operation of the galvano scanner, the pulse laser oscillator is oscillated and the pulse laser beam is incident on the processing point.

JP 2004-66300 A

  The distance from one machining point on the workpiece to the next machining point is not constant. For this reason, the time from the start to the completion of the operation of the galvano scanner varies. As a result, the oscillation period of the pulse laser oscillator also varies. If the oscillation period varies, the pulse energy, the time waveform of the laser pulse, the light intensity distribution, and the like fluctuate, making it difficult to perform high-quality processing.

According to one aspect of the invention,
A laser light source that emits a pulsed laser beam by receiving a trigger signal;
A stage for holding the workpiece,
When a movement command signal for moving the incident position of the pulse laser beam is received on the surface of the object to be processed that is arranged in the path of the pulse laser beam emitted from the laser light source and is held on the stage, A deflector that moves the incident position to the commanded destination and sends a movement completion signal when the movement of the incident position is completed;
A switching element that switches between an open state in which the pulse laser beam emitted from the laser light source is incident on the deflector and a closed state in which the pulse laser beam is not incident on the deflector;
A control device that controls the laser light source, the deflector, and the switching element;
Including a storage unit for storing position information and an incident order of a plurality of processing points to which the laser beam is incident, and frequency information for transmitting the trigger signal;
Based on the frequency information stored in the storage unit to the laser light source, a trigger signal is sent at a constant repetition frequency,
Sending to the deflector a movement command signal for moving the incident position of the pulse laser beam to the next processing point,
After the movement command signal is sent to the deflector, until the movement completion signal is received from the deflector, the switching element is not opened, and after the movement completion signal is received from the deflector, the trigger signal is There is provided a laser processing apparatus that switches the switching element to an open state in synchronization.

According to another aspect of the invention,
A method for determining processing conditions when performing laser processing using the laser processing apparatus described above,
While the frequency information of the trigger signal is different, the position information of the processing point and the incident order are common, and the incident position of the pulse laser beam is moved by controlling the deflector and the switching element in each of a plurality of processing conditions. Measuring the scanning time during which all machining points are scanned;
And determining a suitable frequency of the trigger signal based on the scanning time.

  Since the pulse laser beam is emitted at a constant frequency, variations in pulse energy, pulse time waveform, light intensity distribution, and the like can be suppressed, and processing quality can be improved.

It is the schematic of the laser processing apparatus by an Example. It is a timing chart of various signals at the time of processing using a laser processing device by an example. It is a timing chart in the case of two different frequencies of the trigger signal. It is a graph which shows the measurement result of the relationship between the frequency of a trigger signal, and the required time of a process.

  FIG. 1 shows a schematic diagram of a laser processing apparatus according to an embodiment. When the laser light source 10 receives the trigger signal sig1 from the control device 20, the pulsed laser beam L1 is emitted. The trigger signal sig1 is a pulse signal, and one laser pulse is emitted for one pulse of the trigger signal sig1. For the laser light source 10, for example, a solid-state laser such as an Nd: YAG laser is used.

  The pulse laser beam emitted from the laser light source 10 enters the workpiece 30 held on the XY stage 15 via the switching element 11, the folding mirror 12, the deflector 13, and the fθ lens 14. The switching element 11 switches between the open state and the closed state by receiving the control signal sig2 from the control device 20. In the open state, the incident pulse laser beam is incident on the folding mirror 12. That is, in the open state, the laser beam is incident on the workpiece 30. In the closed state, the incident pulse laser beam is incident on the beam damper 16. That is, in the closed state, the pulsed laser beam does not enter the workpiece. As the switching element 11, an acousto-optic element (AOM), an acousto-optic deflection element (AOD), or the like can be used.

  The fθ lens 14 focuses the pulsed laser beam on the surface of the workpiece 30. A mask imaging method may be employed in which a mask is disposed on the path of the pulse laser beam and the mask is imaged on the surface of the workpiece 30 for processing, or a method in which processing is performed at the position of the beam waist. May be.

  When receiving the movement command signal sig3 from the control device 20, the deflector 13 changes the traveling direction of the pulse laser beam so that the incident position of the pulse laser beam moves on the surface of the workpiece 30. The incident position information of the pulse laser beam is given by a movement command signal sig3. When the movement of the incident position of the pulse laser beam is completed, a movement completion signal sig4 is sent from the deflector 13 to the control device 20.

  As the deflector 13, for example, a galvano scanner including a pair of movable mirrors can be used.

  The XY stage 15 receives the movement command signal sig5 from the control device 20 and moves the workpiece 30. When the movement is completed, a movement completion signal sig6 is sent from the XY stage 15 to the control device 20. At the time of laser processing, by operating the deflector 13 with the workpiece 30 kept stationary, processing within a range that can be scanned by the deflector 13 is performed. By alternately repeating the movement of the workpiece 30 by the XY stage 15 and the machining within the scannable range by the operation of the deflector 13, the entire surface of the workpiece 30 can be machined.

  The control device 20 includes a storage unit 20A that stores various processing conditions. The storage unit 20A stores position information (for example, coordinates) of the processing points defined on the surface of the processing object 30 and the processing order of the processing points. Furthermore, frequency information (for example, a repetition frequency or a cycle of the trigger signal sig1) for transmitting the trigger signal sig1 is stored. In addition, the storage unit 20A stores a time width during which the switching element 11 is kept open.

  FIG. 2 shows a timing chart of laser processing. From the top, the pulse laser beam L1 emitted from the laser light source 10, the trigger signal sig1, the control signal sig2, the movement completion signal sig4 from the deflector 13, the movement command signal sig3 to the deflector 13, and the switching element 11 The rear pulse laser beam L2, the movement command signal sig5 to the XY stage 15, and the movement completion signal sig6 from the XY stage 15 are shown.

  The state where the control signal sig2 rises corresponds to the open state of the switching element 11. The state where the movement completion signal sig4 rises corresponds to the movement of the incident position of the pulse laser beam, and the state where the movement completion signal sig4 corresponds corresponds to the state where the incident position is settled (a state that is almost stationary). That is, the movement completion of the incident position is notified by the falling edge of the movement completion signal sig4. In this specification, the control for lowering the movement completion signal sig4 is referred to as “transmission completion signal sig4”.

  Similarly, in the movement completion signal sig6 of the XY stage 15, the rising state corresponds to the movement of the XY stage 15, and the falling state corresponds to the set state. That is, the movement completion of the XY stage 15 is notified by the falling edge of the movement completion signal sig6.

  When the laser processing apparatus is activated and the start of processing is instructed by the operator, the control apparatus 20 sends a trigger signal sig1 to the laser light source 10 at a constant frequency. An instruction to start machining by the operator is performed by pressing a machining start button or the like, for example. The laser light source 10 emits a pulse laser beam L1 in synchronization with the reception of the trigger signal sig1.

  At time t1, a movement command signal sig5 is sent from the control device 20 to the XY stage 15. The XY stage 15 moves the workpiece 30 to the position commanded by the movement command signal sig5.

  When the movement of the workpiece 30 is completed at time t2, the XY stage 15 notifies the control device 20 of the movement completion by lowering the movement completion signal sig6. When receiving the movement completion notification from the XY stage 15, the control device 20 sends a movement command signal sig3 for moving the incident position of the pulse laser beam to the first processing point to the deflector 13.

  When the movement of the incident position of the pulse laser beam is completed at time t3, the deflector 13 sends a movement completion signal sig4 to the control device 20. The control device 20 keeps the switching element 11 in the closed state until receiving the movement completion signal sig4 from the deflector 13. For this reason, the pulsed laser beam emitted from the laser light source 10 enters the beam damper 16.

  At time t4, the control device 20 sends a trigger signal sig1. At this time, since the movement completion signal sig4 is received from the deflector 13, the control signal sig2 is sent to the switching element 11 in synchronization with the trigger signal sig1, and the switching element 11 is opened. For this reason, the pulse laser beam L2 appears in the path of the laser beam behind the switching element 11 and enters the processing point of the processing object 30.

  The control device 20 stops sending the control signal sig2 when the time width of the open state stored in the storage unit 20A has elapsed since the switching element 11 was opened. As a result, the switching element 11 is closed.

  After the switching element 11 is closed, the control device 20 sends to the deflector 13 a movement command signal sig3 that moves the incident position to the next processing point. The deflector 13 moves the incident position of the pulse laser beam to the commanded processing point.

  When the movement of the incident position of the pulse laser beam is completed at time t5, a movement completion signal sig4 is sent to the control device 20. At this time, the trigger pulse next to the trigger pulse of the trigger signal sig1 transmitted at time t4 is not transmitted.

  At time t6, the next trigger pulse of the trigger signal sig1 is transmitted. At this time, since the movement completion signal sig4 from the deflector 13 has already been received, the control signal sig2 is sent to the switching element 11 in synchronization with the trigger signal sig1. Thereby, the pulse laser beam is incident on the processing point of the processing object 30.

  At time t7, a movement command signal sig3 is sent to the deflector 13, and at time t9, a movement completion signal sig4 is sent from the deflector 13. At time t8 between time t7 and time t9, the trigger signal sig1 is sent out. At this time, since the control device 20 has not received the movement completion signal sig4, the control signal sig2 that opens the switching element 11 Is not sent.

  When the trigger signal sig1 is sent out at time t10 after time t9, the control device 20 sends out a control signal sig2 that opens the switching element 11 in synchronization with the trigger signal sig1.

  By repeating the movement of the incident position of the pulse laser beam and the control for opening the switching element 11, the pulse laser beam can be incident on all machining points within the scannable range of the workpiece 30. When the processing of all the machining points within the scannable range is completed, at time t11, a movement command signal sig5 is sent to the XY stage 15 to move the unprocessed area within the scannable range.

  In the above embodiment, the laser light source 10 emits the pulse laser beam at a constant frequency even if the time from when the deflector 13 is driven until the incident position of the pulse laser beam moves to the next processing point varies. . Therefore, variations in pulse energy, laser pulse time waveform, light intensity distribution, and the like can be suppressed. As a result, processing quality can be improved.

  In the above embodiment, for example, when the control signal sig2 is transmitted in synchronization with the trigger signal sig1 at time t4, the control signal sig2 may be transmitted with a certain delay time from the trigger signal sig1. When the transmission of the control signal sig2 is delayed, the component in the transition period immediately after the rising of the pulse waveform is not incident on the workpiece 30 and only the component after the light intensity is stabilized is incident on the workpiece 30. Can do. Similarly, the switching element 11 may be returned to the closed state before the emission of one laser pulse is completed. Thereby, only the part suitable for processing among the pulse waveforms can be made incident on the processing object 30.

  Next, with reference to FIG. 3A and FIG. 3B, the suitable value of the repetition frequency of a pulse laser beam is demonstrated. The moving time of the incident position from the (n-1) th processing point to the nth processing point is M1, the moving time of the incident position from the nth processing point to the (n + 1) th processing point is M2, and from the (n + 1) th processing point. It is assumed that the moving time of the incident position up to the (n + 2) th processing point is M3.

  3A and 3B show timing charts of the movement completion signal sig4, the trigger signal sig1, and the control signal sig2. FIG. 3B shows an example in which the oscillation frequency of the trigger signal sig1 is lower than that in FIG. 3A.

In any of the examples shown in FIGS. 3A and 3B, the trigger pulse P1 of the trigger signal sig1 is sent out immediately after processing the (n-1) th processing point. In the example shown in FIG. 3A, the second trigger pulse P2 occurs at approximately the same time when the movement completion signal sig4 falls. Therefore, delivery of the pulse Q _n of the control signal sig2 for processing n-th machining point must wait until the third trigger pulse P3.

On the other hand, in the example shown in FIG. 3B, the second trigger pulse P2 is sent out immediately after the movement completion signal sig4 falls. Therefore, in synchronization with the second trigger pulse P2, pulse Q _n of the control signal sig2 for processing n-th machining point it is sent.

In the example shown in FIG. 3A, the movement to the incident position at the (n + 1) -th processing point is completed immediately after the fifth trigger pulse P5 is transmitted. For this reason, the transmission of the pulse Q _{n + 1} of the control signal sig2 for processing the (n + 1) th processing point must wait until the sixth trigger pulse P6. As described above, the machining of the (n + 1) th machining point is synchronized with the third trigger pulse P6 counting from the trigger pulse P3 obtained by machining the nth machining point.

On the other hand, in the example shown in FIG. 3B, the movement completion signal sig4 falls immediately before the fourth trigger pulse P4 is transmitted. For this reason, in synchronization with the trigger pulse P4, the control signal Qn _{+ 1} for processing the (n + 1) th processing point is sent out. That is, the machining of the (n + 1) th machining point is synchronized with the second trigger pulse P4 counted from the trigger pulse P2 obtained by machining the nth machining point.

  The processing of the (n + 2) th processing point is synchronized with the trigger pulse next to the trigger pulse that has performed the (n + 1) th processing in both examples of FIGS. 3A and 3B.

  As shown in FIGS. 3A and 3B, the required time for processing a plurality of processing points does not necessarily become shorter as the frequency of the trigger signal sig1 is higher. It is considered that the optimum frequency of the trigger signal sig1 exists depending on the distribution of the moving time of the incident position of the pulse laser beam.

  FIG. 4 shows the relationship between the frequency of the trigger signal sig1 and the time required for processing when a processing target having about 120,000 processing points is actually processed. The horizontal axis represents the oscillation frequency of the trigger signal sig1 in the unit “Hz”, and the vertical axis represents the required processing time in the unit “second”. It can be seen that when the oscillation frequency of the trigger signal sig1 is in the range from 1000 Hz to 2000 Hz, the machining time is the shortest when the oscillation frequency is 1500 Hz. When processing this workpiece, the required time can be shortened by setting the oscillation frequency of the trigger signal sig1 to 1500 Hz rather than 2000 Hz.

  The oscillation frequency at which the time required for machining is the shortest differs depending on the distribution of the machining points of the workpiece. Hereinafter, a method for determining a suitable oscillation frequency will be described.

  The frequency information of the trigger signal sig1 stored in the storage unit 20A of the control device 20 is different, and the deflector 13 and the switching element 11 are connected using each of a plurality of processing conditions in which the position information and the incident order of the processing points are common. Control. Thereby, the incident position of the pulse laser beam is sequentially moved to a plurality of processing points. At this time, the scanning time for scanning all the processing points is measured.

  Based on the actually measured scanning time, a suitable oscillation frequency of the trigger signal sig1 is determined. For example, a transmission frequency having the shortest scanning time is set as a suitable transmission frequency.

  When the deflector 13 and the switching element 11 are controlled in order to determine a suitable value of the oscillation frequency, it is not necessary to actually emit a pulse laser beam from the laser light source 10. For example, the above-described evaluation can be performed in a state where the laser light source 10 is turned off and a pulse laser beam is not emitted from the laser light source 10.

  In the above embodiment, the case where the processing is performed with one laser beam is shown. However, even when the processing is performed using a plurality of laser beams by branching the laser beam emitted from the laser light source into a plurality of laser beams, The above embodiment can be applied. For example, the switching element 11 shown in FIG. 1 can selectively propagate the laser beam to two paths other than the path incident on the beam damper 16. At this time, the switching element 11 has a first open state in which the pulse laser beam is propagated to the first path, a second open state in which the pulse laser beam is propagated to the second path, and the pulse laser beam is incident on the beam damper. Take one of the closed states to let.

  The deflector 13 and the fθ lens 14 shown in FIG. 1 are disposed in each of the two paths. Two laser beam paths, respectively, the workpiece 30 are arranged. The XY stage 15 may be shared by two routes, or an XY stage may be arranged for each route.

  If the distribution of the machining points and the machining order of the workpieces to be machined by the two paths are the same, movement completion signals sig4 are sent from the two deflectors 13 to the control device 20 almost simultaneously. After receiving the movement completion signal sig4 from both of the two deflectors 13, the control device 20 sets the switching element 11 in the first open state in synchronization with the trigger pulse, and in synchronization with the next trigger pulse. What is necessary is just to make it open.

  When the distribution of the machining points of the workpieces to be machined by the two paths is different, the timings at which the movement completion signals sig4 are sent from the two deflectors 13 are different from each other. In this case, even if the switching element 11 is controlled so that the pulse laser beam propagates to the path that has received the movement completion signal sig4 in a state where the movement completion signal sig4 has been received from only one deflector 13. Good.

  Although the present invention has been described with reference to the embodiments, the present invention is not limited thereto. It will be apparent to those skilled in the art that various modifications, improvements, combinations, and the like can be made.

DESCRIPTION OF SYMBOLS 10 Laser light source 11 Switching element 12 Folding mirror 13 Deflector 14 f (theta) lens 15 XY stage 16 Beam damper 20 Control apparatus 20A Memory | storage part sig1 Trigger signal sig2 Control signal sig3 Movement command signal sig4 Movement completion signal sig5 Movement command signal sig6 Movement completion signal

Claims (6)

A laser light source that emits a pulsed laser beam by receiving a trigger signal;
A stage for holding the workpiece,
When a movement command signal for moving the incident position of the pulse laser beam is received on the surface of the object to be processed that is arranged in the path of the pulse laser beam emitted from the laser light source and is held on the stage, A deflector that moves the incident position to the commanded destination and sends a movement completion signal when the movement of the incident position is completed;
A switching element that switches between an open state in which the pulse laser beam emitted from the laser light source is incident on the deflector and a closed state in which the pulse laser beam is not incident on the deflector;
A control device that controls the laser light source, the deflector, and the switching element;
Including a storage unit for storing position information and an incident order of a plurality of processing points to which the laser beam is incident, and frequency information for transmitting the trigger signal;
Based on the frequency information stored in the storage unit to the laser light source, a trigger signal is sent at a constant repetition frequency,
Sending to the deflector a movement command signal for moving the incident position of the pulse laser beam to the next processing point,
After the movement command signal is sent to the deflector, until the movement completion signal is received from the deflector, the switching element is not opened, and after the movement completion signal is received from the deflector, the trigger signal is A laser processing apparatus that switches the switching element to an open state in synchronization. The control device sends a trigger signal at a constant repetition frequency to the laser light source based on the frequency information stored in the storage unit while driving the deflector to process the plurality of processing points. The laser processing apparatus according to claim 1. The storage unit of the control device stores a time width for opening the switching element, and the control device stores the time width stored in the storage unit after switching the switching element to the open state. When elapses, the switching element is returned to the closed state,
3. The laser processing apparatus according to claim 1, wherein after the switching element is returned to the closed state, a movement command signal for moving the incident position of the pulse laser beam to the next processing point is sent to the deflector. A laser light source that emits a pulsed laser beam by receiving a trigger signal;
A stage for holding the workpiece,
When the position command signal indicating the incident position of the pulse laser beam is received on the surface of the object to be processed that is arranged in the path of the pulse laser beam emitted from the laser light source and is held on the stage, the incident of the pulse laser beam is received. A deflector that moves the position to the commanded position and sends a movement completion signal when the movement of the incident position is completed;
When a movement command signal for moving the incident position of the pulse laser beam is received on the surface of the object to be processed that is arranged in the path of the pulse laser beam emitted from the laser light source and is held on the stage, A deflector that moves the incident position to the commanded destination and sends a movement completion signal when the movement of the incident position is completed;
A switching element that switches between an open state in which the pulse laser beam emitted from the laser light source is incident on the deflector and a closed state in which the pulse laser beam is not incident on the deflector;
A control device that controls the laser light source, the deflector, and the switching element;
Including a storage unit for storing position information and an incident order of a plurality of processing points to which the laser beam is incident, and frequency information for transmitting the trigger signal;
Based on the frequency information stored in the storage unit to the laser light source, a trigger signal is sent at a constant repetition frequency,
Sending to the deflector a movement command signal for moving the incident position of the pulse laser beam to the next processing point,
After the movement command signal is sent to the deflector, until the movement completion signal is received from the deflector, the switching element is not opened, and after the movement completion signal is received from the deflector, the trigger signal is A method of determining processing conditions when performing laser processing using a laser processing apparatus that switches the switching element to an open state in synchronization,
While the frequency information of the trigger signal is different, the position information of the processing point and the incident order are common, and the incident position of the pulse laser beam is moved by controlling the deflector and the switching element in each of a plurality of processing conditions. Measuring the scanning time during which all machining points are scanned;
And determining a suitable frequency of the trigger signal based on the scanning time. The control device sends a trigger signal at a constant repetition frequency to the laser light source based on the frequency information stored in the storage unit while driving the deflector to process the plurality of processing points. The processing condition determination method according to claim 4. 6. The method according to claim 4 , wherein, in the step of measuring the scanning time, the deflector and the switching element are controlled in a state where a pulse laser beam is not emitted from the laser light source even when the trigger signal is transmitted to the laser light source. A method for determining the described processing conditions.

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