Laser processing apparatus, method of operating laser processing apparatus, and laser monitoring apparatus for controlling laser processing apparatus

Abstract

A laser processing apparatus is provided. The laser processing apparatus includes a light source unit configured to emit a first laser beam and a second laser beam, a beam shaping unit configured to generate a processing beam from the first laser beam and the second laser beam based on an operation mode of the laser processing apparatus, and a beam measurement unit configured to measure a waveform of at least one laser beam, wherein, when the operation mode is a processing mode, the first laser beam and the second laser beam overlap each other, and the beam measurement unit measures a waveform of the processing beam, and when the operation mode is a test mode, the first laser beam and the second laser beam do not overlap each other, and the beam measurement unit measures waveforms of the first laser beam and the second laser beam.

Description

LASER PROCESSING APPARATUS, METHOD OF OPERATING LASER PROCESSING APPARATUS, AND LASER MONITORING APPARATUS FOR CONTROLLING LASER PROCESSING APPARATUS

[0001] The present disclosure relates to a laser processing apparatus.

[0002] The present disclosure relates to a method of operating a laser processing apparatus.

[0003] The present disclosure relates to a laser monitoring apparatus.

[0004] The present disclosure relates to a laser monitoring system.

[0005] A laser processing apparatus is an apparatus that processes processing targets such as wafers using laser beams. For example, a laser processing apparatus may perform dicing, annealing, grooving, scribing, and / or drilling on a processing target.

[0006] Meanwhile, as a period of use of a laser processing apparatus increases, the characteristics (for example, a timing) of a laser beam radiated onto a processing target change. As a result, processing quality may degrade. Therefore, there is a need for a technology for monitoring a laser beam output from a laser processing apparatus in real time and adjusting the characteristics of the laser beam.

[0007] The present disclosure is directed to providing a laser processing apparatus capable of controlling the characteristics of a laser beam.

[0008] Provided are a variable pulse width flat-top laser device for improving uniformity of a flat-top beam and more efficiently configuring laser beams and an optical system and an operating method therefor.

[0009] The present disclosure is also directed to providing a laser monitoring apparatus which monitors a laser beam in real time to control a laser processing apparatus.

[0010] One aspect of the present disclosure provides a laser processing apparatus including a light source unit configured to emit a first laser beam and a second laser beam, a beam shaping unit configured to receive the first laser beam and the second laser beam and generate a processing beam from the first laser beam and the second laser beam based on an operation mode of the laser processing apparatus, and a beam measurement unit configured to measure a waveform of at least one of the first laser beam, the second laser beam, and the processing beam, wherein, when the operation mode is a processing mode, the first laser beam and the second laser beam overlap each other, and the beam measurement unit measures a waveform of the processing beam; and when the operation mode is a test mode, the first laser beam and the second laser beam do not overlap each other, and the beam measurement unit measures waveforms of the first laser beam and the second laser beam.

[0011] The processing beam may be a flat-top laser beam generated by overlapping the first laser beam and the second laser beam, and the first laser beam and the second laser beam may be emitted at different timings.

[0012] When the processing beam is abnormal in the processing mode, the laser processing apparatus may enter the test mode.

[0013] The laser processing apparatus may further include an optical path forming unit disposed between the light source unit and the beam shaping unit to form optical paths of the first laser beam and the second laser beam, wherein the optical path forming unit includes a plurality of mirrors and a mirror moving unit configured to move at least one mirror of the plurality of mirrors, and the mirror moving unit moves the at least one mirror to adjust a distance between the plurality of mirrors and adjust pulse widths of the first laser beam and the second laser beam.

[0014] The light source unit may emit the first laser beam at a first timing, may emit the second laser beam at a second timing that is later than the first timing, and may emit a third laser beam at a third timing that is later than the second timing, and the beam shaping unit may generate a first processing beam from the first laser beam and the second laser beam and may generate a second processing beam from the third laser beam, wherein the first processing beam does not overlap the second processing beam.

[0015] The first processing beam and the second processing beam may be used in different processes.

[0016] The laser processing apparatus may further include a stage on which a processing target is seated, wherein the stage moves the processing target inside an optical path of the processing beam in the processing mode and moves the processing target outside the optical path of the processing beam in the test mode.

[0017] The laser processing apparatus may further include a communication unit configured to transmit the waveform of the laser beam measured through the beam measurement unit to a laser monitoring apparatus and receive information about a pulse width of the laser beam from the laser monitoring apparatus.

[0018] Another aspect of the present disclosure provides a laser monitoring apparatus including a communication interface including at least one communication circuit, a memory configured to store at least one instruction, and a processor configured to execute the at least one instruction, wherein the processor acquires and analyzes a waveform of a laser beam emitted from a laser processing apparatus, when the laser processing apparatus is in a processing mode, the processor controls the laser processing apparatus such that a first laser beam and a second laser beam overlap each other and acquires a waveform of a processing beam generated based on the first laser beam and the second laser beam, and when the laser processing apparatus is in a test mode, the processor controls the laser processing apparatus such that the first laser beam and the second laser beam do not overlap each other and acquires waveforms of the first laser beam and the second laser beam.

[0019] The processor may analyze the waveform of the processing beam to determine whether the processing beam is abnormal, and when it is determined that the processing beam is abnormal, the processor may control the laser processing apparatus to enter the test mode.

[0020] The processor may compare the waveform of the processing beam with a pre-stored waveform to determine whether the processing beam is abnormal.

[0021] When the laser processing apparatus is in the test mode, the processor may identify a laser beam that is abnormal between the first laser beam and the second laser beam, may obtain a value for adjusting parameters of the identified laser beam, and may control the laser processing apparatus based on the obtained value.

[0022] The parameter may be an emission timing, a pulse width, a pulse height, a pulse area, or a pulse rise time.

[0023] Still another of the present disclosure provides a method of operating a laser processing apparatus, the method including emitting a first laser beam and a second laser beam, generating a processing beam from the first laser beam and the second laser beam based on an operation mode of the laser processing apparatus, and measuring a waveform of at least one of the first laser beam, the second laser beam, and the processing beam, wherein, when the operation mode is a processing mode, the first laser beam and the second laser beam overlap each other, and a waveform of the processing beam is measured, and wherein, when the operation mode is a test mode, the first laser beam and the second laser beam do not overlap each other, and waveforms of the first laser beam and the second laser beam are measured.

[0024] The processing beam may be a flat-top laser beam generated by overlapping the first laser beam and the second laser beam, and the first laser beam and the second laser beam may be emitted at different timings.

[0025] The method may further include, when the processing beam is abnormal in the processing mode, entering the test mode.

[0026] The method may further include moving a mirror included in the laser processing apparatus to adjust pulse widths of the first laser beam and the second laser beam.

[0027]

[0028] The disclosed technology may have the following effects. However, since a specific embodiment is not construed as including all of the following effects or only the following effects, it should not be understood that the scope of the disclosed technology is limited to the specific embodiment.

[0029] According to embodiments of the present disclosure, the characteristics of a laser beam can be adjusted by monitoring a laser beam output from a laser processing apparatus. Accordingly, the characteristics of the laser beam can be maintained to prevent the degradation in processing quality.

[0030] In a variable pulse width flat-top laser device and an operating method therefor according to a disclosure embodiment, an optical system configuration of an existing laser processing device may be maintained, a larger number of laser beams may be controlled, and uniformity may be improved by adjusting a pulse width and energy of laser beams.

[0031] The above content of the present disclosure does not include a complete list of all aspects of the present disclosure. The present disclosure should be understood to include all methods, apparatuses, and systems practicable from all suitable combinations of the various aspects disclosed in the foregoing summary as well as the following detailed description and claims. In addition, effects which may be achieved or expected from the embodiments of the present disclosure may be directly or implicitly disclosed in the detailed description of the embodiments of the present disclosure. For example, various effects expected according to the embodiments of the present disclosure will be disclosed in the following detailed description.

[0032] Aspects, features, and advantages of specific embodiments of the present disclosure will become more apparent through the following description with reference to the accompanying drawings.

[0033] FIG. 1 is a block diagram of a laser processing system according to one embodiment of the present disclosure.

[0034] FIG. 2 is a schematic diagram of a laser processing apparatus according to one embodiment of the present disclosure.

[0035] FIG. 3 shows a driving timing of a laser source according to one embodiment.

[0036] FIG. 4 shows a driving timing of a laser source according to another embodiment.

[0037] FIG. 5 shows a driving timing of a laser source according to still another embodiment.

[0038] FIG. 6 is a flowchart illustrating the operation of a laser monitoring apparatus according to one embodiment of the present disclosure.

[0039] FIG. 7 is a graph showing a waveform of a processing beam according to one embodiment of the present disclosure.

[0040] FIG. 8A shows schematic diagrams illustrating a method of adjusting a pulse width of a laser beam according to one embodiment of the present disclosure.

[0041] FIG. 8B shows schematic diagrams illustrating a method of adjusting a pulse width of a laser beam according to one embodiment of the present disclosure.

[0042] FIG. 9A shows graphs showing a waveform of a processing beam according to various embodiments of the present disclosure.

[0043] FIG. 9B shows graphs showing a waveform of a processing beam according to various embodiments of the present disclosure.

[0044] FIG. 10 is a schematic diagram of a beam measurement unit according to one embodiment of the present disclosure.

[0045] FIG. 11 is a schematic diagram illustrating a laser beam that is incident on a beam shaping unit according to one embodiment of the present disclosure.

[0046] The advantages and features of the present disclosure and methods of achieving them will become apparent with reference to embodiments of the present disclosure described in detail below along with the attached drawings. The disclosure may, however, be embodied in many different forms and should not be construed as limited to embodiments set forth herein; rather these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to one of ordinary skill in the art, and the scope of the disclosure is defined only by the accompanying claims. Like reference numerals denote like elements throughout, and in the drawings, sizes or thicknesses of elements may be exaggerated for clarity of explanation. In addition, portions irrelevant to the descriptions of the present disclosure will be omitted in the drawings for clear descriptions of the present disclosure.

[0047] The terms used herein will be briefly described, and the present disclosure will be described in detail.

[0048] The terms used herein are those general terms currently widely used in the art in consideration of functions in the present disclosure but the terms may vary according to the intention of one of ordinary skill in the art, precedents, or new technology in the art. Also, some of the terms used herein may be arbitrarily chosen by the present applicant, and in this case, these terms are defined in detail below. Accordingly, the specific terms used herein should be defined based on the unique meanings thereof and the whole context of the present disclosure.

[0049] It will be understood that when a certain part "includes" a certain component, the part does not exclude another component but may further include another component, unless the context clearly dictates otherwise.

[0050] Terms used herein will be described in brief, and then the present disclosure will be described in detail.

[0051] The terms used herein have been selected as general terms which are widely used at present in consideration of the functions of the present disclosure, and this may be altered according to the intent of an operator skilled in the art, conventional practice, or introduction of new technology. Also, in a specific case, a term is arbitrarily selected by the applicant, and a meaning of the term will be described in detail in a corresponding description portion of the present disclosure. Therefore, the terms used herein should be defined based on the overall content of the present disclosure instead of a simple name of each of the terms.

[0052] Since the embodiments of the present disclosure can apply various transformations and have various embodiments, specific embodiments will be illustrated in the drawings and described in detail in the detailed description. However, this is not intended to limit the present disclosure to particular modes of practice, and it is to be appreciated that all changes, equivalents, and substitutes that do not depart from the spirit and technical scope of the present disclosure are encompassed in the present disclosure. In describing the embodiments, when it is determined that the specific description of the known related art unnecessarily obscures the gist of the disclosure, the detailed description thereof will be omitted.

[0053] The terms "first," "second," and the like may be simply used for description of various components, but their meanings are not limited to restrictive meanings. The terms are used only to distinguish one component from another.

[0054] An expression used in the singular encompasses the expression of the plural, unless it has a clearly different meaning in the context. In the present application, the term "comprise" or "has" is used to specify existence of a feature, a numbers, a process, an operation, a component, a part, or a combination thereof, and it will be understood that the possibility of the existence or additional of one or more other features or numbers, processes, operations, components, parts, or combinations thereof is not excluded in advance.

[0055] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily practice the present disclosure. However, the present disclosure may be implemented in various forms and is not limited to the embodiments described herein. In order to clearly describe the present disclosure in the drawings, parts not related to the description are omitted, and similar parts are given similar reference numerals throughout the specification.

[0056] FIG. 1 is a block diagram of a laser processing system according to one embodiment of the present disclosure.

[0057] Referring to FIG. 1, a laser processing system 1000 may include a laser processing apparatus 1100, a laser monitoring apparatus 1200, a driving signal generator 1300, and a delay generator 1400.

[0058] The laser processing apparatus 1100 may process a processing target (for example, a wafer) using a laser beam. For example, the laser processing apparatus 1100 may perform annealing, smoothing, dicing, grooving, scribing, and / or drilling. The laser processing apparatus 1100 may include a light source unit 1110, an optical path forming unit 1120, a beam shaping unit 1130, an imaging optical system 1140, a beam measurement unit 1150, a communication unit 1160, and a control unit 1170.

[0059] The laser processing apparatus 1100 may have a plurality of operation modes. For example, the plurality of operation modes may include a processing mode and a processing preparation mode. The processing mode may be a mode of processing a processing target using a laser beam. The processing preparation mode may be a mode of stopping the processing of the processing target and preparing subsequent processing. The processing preparation mode may include a test mode and an adjustment mode. The test mode may be a mode of testing a laser beam emitted from the laser processing apparatus 1100. The adjustment mode may be a mode of adjusting parameters of the laser beam based on a test result. The parameters of the laser beam may include an emission timing, a pulse width, a pulse height, a pulse area, and / or a pulse rise time.

[0060] The light source unit 1110 may emit a laser beam. In particular, the light source unit 1110 may emit a plurality of laser beams. For example, the light source unit 1110 may emit a first laser beam and a second laser beam. The light source unit 1110 may emit the plurality of laser beams at different timings. For example, the light source unit 1110 may emit the first laser beam at a first timing and may emit the second laser beam at a second timing that is later than the first timing. The light source unit 1110 may include a plurality of laser sources. For example, the light source unit 1110 may include a first laser source that outputs the first laser beam and a second laser source that outputs the second laser beam.

[0061] The optical path forming unit 1120 may form an optical path of a laser beam emitted from the light source unit 1110. The optical path forming unit 1120 may include various optical components. For example, the optical path forming unit 1120 may include a lens, a mirror, a beam splitter, and / or a wave plate. In addition, the optical path forming unit 1120 may include a moving unit (for example, a mirror moving unit) for moving the optical component.

[0062] The beam shaping unit 1130 may shape a laser beam emitted from the light source unit 1110. For example, the beam shaping unit 1130 may convert the form of a laser beam into the form of a flat-top beam with uniform energy distribution. The beam shaping unit 1130 may include a homogenizing optical system. The homogenizing optical system may include a cylindrical lens array.

[0063] The beam shaping unit 1130 may generate a processing beam from a plurality of laser beams emitted from the light source unit 1110. For example, the beam shaping unit 1130 may generate a processing beam from the first laser beam and the second laser beam. Specifically, the beam shaping unit 1130 may generate a processing beam by overlapping the first laser beam and the second laser beam.

[0064] The beam shaping unit 1130 may receive a plurality of laser beams through an incidence surface. In this case, respective laser beams be incident on different regions of the incidence surface. For example, the incidence surface may include four quadrants. First to fourth laser beams may be incident on first to fourth quadrants, respectively.

[0065] The imaging optical system 1140 may be configured to project a processing beam generated by the beam shaping unit 1130 onto a processing target. The imaging optical system 1140 may include at least one lens and a reflective member. The reflective member may be a reflective mirror or a total reflective prism.

[0066] The beam measurement unit 1150 may be a component that receives a laser beam to acquire a waveform of the received laser beam. For example, the beam measurement unit 1150 may include a sensor. In addition, the beam measurement unit 1150 may include an energy meter for measuring the energy of a laser beam. The beam measurement unit 1150 may receive a laser beam directly through the sensor or may receive a laser beam scattered by the energy meter through the sensor.

[0067] Based on the operation mode, the beam measurement unit 1150 may measure a waveform of a processing beam generated from a plurality of laser beams or may measure a waveform of an individual laser beam. For example, in the processing mode, the beam measurement unit 1150 may measure a waveform of a processing beam. In the test mode, the beam measurement unit 1150 may measure a waveform of an individual laser beam.

[0068] The beam measurement unit 1150 may be disposed adjacent to a stage that supports a processing target. Accordingly, the beam measurement unit 1150 may measure a waveform of a laser beam having almost the same form as a laser beam radiated onto a processing target.

[0069] Meanwhile, the beam measurement unit 1150 may be a part of the laser processing apparatus 1100, or may be implemented as a separate device.

[0070] The communication unit 1160 is a component for communicating with external devices. For example, the communication unit 1160 may receive a driving signal for driving the light source unit 1110 from the delay generator 1400. The communication unit 1160 may transmit a waveform of a laser beam acquired through the beam measurement unit 1150 to the laser monitoring apparatus 1200. The communication unit 1160 may receive information about a pulse width of a laser beam from the laser monitoring apparatus 1200.

[0071] The control unit 1170 may be a component for controlling the components of the laser processing apparatus 1100. For example, the control unit 1170 may control a driving timing of the light source unit 1110 or may control the movement of the stage on which a processing target is to be seated.

[0072] The laser monitoring apparatus 1200 may monitor a waveform of a laser beam output from the laser processing apparatus 1100 and may control the laser processing apparatus 1100 based on the monitored waveform.

[0073] The laser monitoring apparatus 1200 may include a communication interface 1210, a memory 1220, and a processor 1230. The communication interface 1210 may include at least one communication circuit. For example, the communication interface 1210 may receive a waveform of a laser beam from the laser processing apparatus 1100. The communication interface 1210 may transmit control commands to the driving signal generator 1300 and the delay generator 1400. The control commands may include a command for generating a driving signal and a value for adjusting a timing at which a laser beam is emitted.

[0074] The memory 1220 may store commands or data related to the components of the laser monitoring apparatus 1200. The memory 1220 may store instructions for controlling the laser processing apparatus 1100 and the laser monitoring apparatus 1200. The memory 1220 may store reference information for determining an abnormality in a laser beam. The reference information may include a reference waveform.

[0075] The processor 1230 may be electrically connected to the memory 1220 to control the overall function and operation of the laser monitoring apparatus 1200. The processor 1230 may execute the instruction stored in the memory 1220 to control the laser monitoring apparatus 1200.

[0076] For example, the processor 1230 may determine whether a processing beam output from the laser processing apparatus 1100 is abnormal. According to a determination result, the processor 1230 may determine the operation mode of the laser processing apparatus 1100. The processor 1230 may analyze a waveform of an individual laser beam to derive values for adjusting parameters of the individual laser beam. Meanwhile, in the present disclosure, unless otherwise specified, operations performed by the laser monitoring apparatus 1200 may be understood as being performed by the processor 1230.

[0077] The driving signal generator 1300 may generate a driving signal (or trigger signal) under the control of the laser monitoring apparatus 1200. The driving signal may be a pulse signal for driving the light source unit 1110. The driving signal generator 1300 may transmit the driving signal to the delay generator 1400.

[0078] The delay generator 1400 may split the driving signal received from the driving signal generator 1300 into a plurality of driving signals. The delay generator 1400 may adjust a timing of each of the plurality of split driving signals based on a control command received from the laser monitoring apparatus 1200. Each of the plurality of laser sources included in the light source unit 1110 may output a laser beam according to each driving signal.

[0079] Meanwhile, the driving signal generator 1300 and the delay generator 1400 are shown as separate devices, but may also be integrated and implemented as one device.

[0080] FIG. 2 is a schematic diagram of a laser processing apparatus according to one embodiment of the present disclosure.

[0081] Referring to FIG. 2, a laser processing apparatus 1100 may include a light source unit 1110, an optical path forming unit 1120, a beam shaping unit 1130, an imaging optical system 1140, a beam measurement unit 1150, a beam splitter BS, and a stage S.

[0082] The light source unit 1110 may include first to fourth laser sources 1111, 1112, 1113, and 1114 that emit first to fourth laser beams L1, L2, L3, and L4, respectively. The first to fourth laser beams L1, L2, L3, and L4 may be emitted at different timings. For example, the first laser beam L1 may be emitted at a first timing, the second laser beam L2 may be emitted at a second timing that is later than the first timing, the third laser beam L3 may be emitted at a third timing that is later than the second timing, and the fourth laser beam L4 may be emitted at a fourth timing that is later than the third timing.

[0083] The timings at which the laser beams L1, L2, L3, and L4 are emitted may vary according to an operation mode of the laser processing apparatus 1100. For example, in a processing mode, the timings may be adjusted such that at least two laser beams overlap each other. In a test mode, the timings may be adjusted such that none of the laser beams overlap each other. In addition, even within the processing mode, the timings at which the laser beams L1, L2, L3, and L4 are emitted may vary according to a recipe of a processing beam.

[0084] The laser beams L1, L2, L3, and L4 may pass through the optical path forming unit 1120 and then may be incident on different regions of an incidence surface of the beam shaping unit 1130. For example, the laser beams L1, L2, L3, and L4 may be incident on first to fourth quadrants, respectively.

[0085] The beam shaping unit 1130 may receive the laser beams L1, L2, L3, and L4 to output at least one processing beam L. The number of processing beams may vary according to timings at which the laser beams L1, L2, L3, and L4 are emitted. In one embodiment, the beam shaping unit 1130 may output a first processing beam in which the first to third laser beams L1, L2, and L3 overlap each other and a second processing beam into which the fourth laser beam L4 is shaped. In another embodiment, the beam shaping unit 1130 may output the first processing beam in which the first and second laser beams L1 and L2 overlap each other and the second processing beam in which the third and fourth laser beams L3 and L4 overlap each other. Meanwhile, the processing beam L according to the present disclosure is not limited to a beam generated by overlapping a plurality of laser beams in time, and may also include a beam generated by refining a shape of a single laser beam.

[0086] The imaging optical system 1140 may receive the processing beam L output from the beam shaping unit 1130 to project the processing beam L onto a processing target T seated on the stage S. Accordingly, processing may be performed on the processing target T.

[0087] The beam measurement unit 1150 may be configured to acquire a laser beam output from the beam shaping unit 1130. In one embodiment, the beam measurement unit 1150 may be disposed to receive a laser beam split by the beam splitter BS. In another embodiment, the beam measurement unit 1150 may be disposed to receive a laser beam that has not yet been incident on the imaging optical system 1140.

[0088] A laser beam acquired by the beam measurement unit 1150 may vary according to the operating mode of the laser processing apparatus 1100. In the processing mode, the beam measurement unit 1150 may acquire the processing beam L. In the test mode, the beam measurement unit 1150 may acquire the plurality of laser beams L1, L2, L3, and L4 that do not overlap each other.

[0089] The stage S may move the processing target T based on the operation mode of the laser processing apparatus 1100. In the processing mode, the stage S may position the processing target T inside an optical path of the processing beam L. In the test mode, the stage S may position the processing target T outside the optical path of the processing beam L.

[0090] FIGS. 3 to 5 show a driving timing of a laser source according to various embodiments. FIGS. 3 and 4 show the driving timing of the laser source in the processing mode, and FIG. 5 shows the driving timing of the laser source in the test mode.

[0091] In FIGS. 3 to 5, (a) indicates a driving signal output from a driving signal generator 1300. (b), (c), (d), and (e) indicate driving signals of which timings are adjusted in a delay generator 1400. The driving signals may each be applied to one of the first to fourth laser sources 1111, 1112, 1113, and 1114. The first to fourth laser sources 1111, 1112, 1113, and 1114 may output the first to fourth laser beams L1, L2, L3, and L4, respectively. Specifically, the first laser source 1111 is driven by the driving signal (b) in FIGS. 3 to 5, the second laser source 1112 may be driven by the driving signal (c) in FIGS. 3 to 5, the third laser source 1113 may be driven by the driving signal (d) in FIGS. 3 to 5, and the fourth laser source 1114 may be driven by the driving signal (e) of FIGS. 3 to 5. In FIGS. 3 to 5, (f) indicates a waveform of a laser beam output by the light source unit 1110 according to a driving signal. t1, t2, t3, and t4 are emission timings of the first to fourth laser beams, respectively.

[0092] Referring to FIG. 3, the first to fourth laser beams L1, L2, L3, and L4 are emitted at uniform time intervals, and laser beams adjacent in time may overlap each other. The first to fourth laser beams L1, L2, L3, and L4 may be incident on the beam shaping unit 1130 to be generated into one processing beam. In this case, the beam measurement unit 1150 may measure a waveform of a processing beam formed by overlapping the first to fourth laser beams L1, L2, L3, and L4.

[0093] Referring to FIG. 4, the first and second laser beams L1 and L2 may overlap each other in time and may be incident on the beam shaping unit 1130 to be generated into a first processing beam. The third and fourth laser beams L3 and L4 may overlap each other in time and may be incident on the beam shaping unit 1130 to be generated into a second processing beam. In this case, the beam measurement unit 1150 may measure waveforms of the first processing beam and the second processing beam. Meanwhile, the first processing beam and the second processing beam may be spaced apart from each other and may not overlap each other. In this case, the first processing beam and the second processing beam may be used in different processes. For example, the first processing beam may be used in an annealing or melting process, and the second processing beam may be used in a smoothing process.

[0094] Referring to FIG. 5, the first to fourth laser beams L1, L2, L3, and L4 do not overlap each other in time. Even when the first to fourth laser beams L1, L2, L3, and L4 are incident on the beam shaping unit 1130, the first to fourth laser beams L1, L2, L3, and L4 may be generated as independent and separate laser beams. Accordingly, the beam measurement unit 1150 may measure waveforms of the individual laser beams L1, L2, L3, and L4.

[0095] FIG. 6 is a flowchart illustrating the operation of a laser monitoring apparatus according to one embodiment of the present disclosure.

[0096] Referring to FIG. 6, a laser monitoring apparatus 1200 may acquire a waveform of a processing beam (S610). The waveform of the processing beam may be measured by a beam measurement unit 1150 of the laser processing apparatus 1100 and transmitted to a laser monitoring apparatus 1200.

[0097] The laser monitoring apparatus 1200 may determine whether the processing beam is abnormal (S620). The laser monitoring apparatus 1200 may compare the waveform of the processing beam with a pre-stored waveform to determine whether the processing beam is abnormal. For example, when the waveform of the processing beam does not match the pre-stored waveform, the laser monitoring apparatus 1200 may determine that the processing beam is abnormal. On the other hand, when the waveform of the processing beam matches the pre-stored reference waveform, the laser monitoring apparatus 1200 may determine that the processing beam is normal. Whether two waveforms match each other may be determined based on a similarity between the two waveforms. For example, when a similarity between two waveforms is greater than or equal to a threshold, it may be determined that the two waveforms match each other. On the other hand, when a similarity between two waveforms is less than the threshold, it may be determined that the two waveforms do not match each other.

[0098] When it is determined that the processing beam is abnormal (S620-YES), the laser monitoring apparatus 1200 may control the laser processing apparatus 1100 to enter a test mode (S630). For example, the laser monitoring apparatus 1200 may transmit a command for entering the test mode to the laser processing apparatus 1100. When entering the test mode, the laser processing apparatus 1100 may stop processing on a processing target and may move a stage to move the processing target outside an optical path of a laser beam. The laser monitoring apparatus 1200 may control a delay generator 1400 such that driving timings of laser sources are set as shown in FIG. 5. Accordingly, the laser processing apparatus 1100 may emit laser beams at timings that do not overlap each other.

[0099] The laser monitoring apparatus 1200 may analyze waveforms of individual laser beams to identify a laser beam that is abnormal (S640). For example, the laser monitoring apparatus 1200 may acquire a waveform of each of laser beams L1, L2, L3, and L4. In this case, the waveforms of the laser beams may not overlap each other. The laser monitoring apparatus 1200 may compare the waveform of each laser beam with a pre-stored reference waveform to determine whether each laser beam is abnormal. For example, when a difference between the waveform of the first laser beam and the reference waveform is greater than a threshold, the laser monitoring apparatus 1200 may determine that the first laser beam is abnormal. That is, the laser monitoring apparatus 1200 may identify the first laser beam as the laser beam that is abnormal.

[0100] The laser monitoring apparatus 1200 may obtain a value for adjusting parameters of the identified laser beam (S650). For example, parameters of a laser beam may include an emission timing, a pulse width, a pulse height, a pulse area, and / or a pulse rise time. The laser monitoring apparatus 1200 may obtain a value allowing the parameters of the identified laser beam to be the same as parameters of the reference waveform. In this case, the obtained value may be a value based on a relative difference between the parameters of the identified laser beam and the parameters of the reference waveform.

[0101] The laser monitoring apparatus 1200 may control the laser processing apparatus based on the obtained value (S660). In one embodiment, the laser monitoring apparatus 1200 may control the delay generator 1400 to adjust an emission timing of a laser beam. In another embodiment, the laser monitoring apparatus 1200 may control an optical path forming unit 1120 to adjust a pulse width of a laser beam. Specifically, the optical path forming unit 1120 may move a mirror under the control of the laser monitoring apparatus 1200.to adjust a length of an optical path of a laser beam. Accordingly, a pulse width of a laser beam may be adjusted. In another embodiment, the laser monitoring apparatus 1200 may adjust a pulse height of a laser beam. Specifically, the laser monitoring apparatus 1200 may adjust a pulse width of a laser beam by adjusting an output voltage of a power supply that supplies power to the laser processing apparatus 1100.

[0102] FIG. 7 is a graph showing a waveform of a processing beam according to one embodiment of the present disclosure.

[0103] Referring to FIG. 7, a solid line graph indicates a measured waveform of a processing beam, and a dotted line graph indicates a pre-stored reference waveform. The waveform of the processing beam lags behind the reference waveform in time and also has a different pulse height therefrom. However, since the processing beam is a beam generated by overlapping a plurality of laser beams, it is difficult to determine what laser beam is specifically abnormal and whether the processing beam is abnormal. Accordingly, the laser monitoring apparatus 1200 may adjust an emission timing such that respective laser beams do not overlap each other and may analyze waveforms of individual laser beams to detect a laser beam that is abnormal. The laser monitoring apparatus 1200 may adjust the parameters of the detected laser beam.

[0104] Meanwhile, the laser monitoring apparatus 1200 may monitor the processing beam in real time while the laser processing apparatus 1100 performs processing using the processing beam. Therefore, there is an advantage in that a processing operation of the laser processing apparatus 1100 does not need to be stopped to test the processing beam.

[0105] FIG. 8A shows schematic diagrams illustrating a method of adjusting a pulse width of a laser beam according to one embodiment of the present disclosure. FIG. 8B shows schematic diagrams illustrating a method of adjusting a pulse width of a laser beam according to one embodiment of the present disclosure.

[0106] As described above, a laser processing apparatus 1100 may move optical components to adjust a length of an optical path of a laser beam, thereby adjusting a pulse width of the laser beam. FIG. 8A shows the arrangement of the optical components before the pulse width is adjusted, and FIG. 8B shows the arrangement of the optical components after the pulse width is adjusted. In one embodiment, the optical components may include reflective members 1121, 1122, 1123, 1124, and 1125.

[0107] Referring to FIG. 8A, the reflective members 1121, 1122, 1123, 1124, and 1125 may be positioned outside an optical path of a first laser beam L1. Accordingly, the first laser beam L1 may not reach the reflective members 1121, 1122, 1123, 1124, and 1125. In this case, a length of the optical path of the first laser beam L1 may be a first length.

[0108] Referring to FIG. 8B, the laser processing apparatus 1100 may position the reflective members 1121, 1122, 1123, 1124, and 1125 on the optical path of the first laser beam L1. Accordingly, an optical path of light reflected by the reflective members 1121, 1122, 1123, 1124, and 1125 may be added to the optical path of the first laser beam L1. Accordingly, the length of the optical path of the first laser beam L1 may be greater than the first length. In this case, a pulse width of the first laser beam L1 may be greater than that in FIG. 8A. On the other hand, a position of an optical component not shown in FIG. 8A may also be adjusted to reduce the pulse width of the first laser beam L1, thereby reducing the optical path of the first laser beam L1.

[0109] In this way, the laser processing apparatus 1100 may adjust the length of the optical path of the first laser beam L1 to adjust the pulse width of the first laser beam L1. Meanwhile, the first laser beam L1 may be a laser beam that has not yet passed through a beam shaping unit 1130 or may be a laser beam that has passed through the beam shaping unit 1130. In addition, the reflective members 1121, 1122, 1123, 1124, and 1125 may be mirrors or beam splitters.

[0110] FIG. 9A shows graphs showing a waveform of a processing beam according to various embodiments of the present disclosure. FIG. 9B shows graphs showing a waveform of a processing beam according to various embodiments of the present disclosure. FIG. 9A shows a waveform of a first processing beam LL1 according to a first embodiment, and FIG. 9B shows waveforms of a second processing beam LL2 and a third processing beam LL3 according to a second embodiment.

[0111] Referring to FIGS. 9A and 9B, the first processing beam LL1 may be generated by combining first to fourth laser beams that are sequentially emitted. The second processing beam LL2 may be generated by combining the first to third laser beams. The third processing beam LL3 may be generated by shaping the fourth laser beam. The first processing beam LL1 may be used in a first processing mode. For example, the first processing mode may be an operation mode of performing annealing on a processing target. The second processing beam LL2 and the third processing beam LL3 may be used in a second processing mode. For example, the second processing mode may be an operation mode of performing melting and smoothing on the processing target. The second processing beam LL2 may be used for a melting process, and the third processing beam LL3 may be used for a smoothing process.

[0112] A laser processing apparatus 1100 may enter the first processing mode or the second processing mode based on a set routine or under the control of a laser monitoring apparatus 1200. In a processing mode that the laser processing apparatus 1100 enters, the laser processing apparatus 1100 may emit laser beams at timings for generating a processing beam corresponding to the processing mode.

[0113] Meanwhile, a range of a region heated by the processing beam may vary according to a pulse width of the processing beam. Specifically, as the pulse width of the processing beam increases, the range of the region heated by the processing beam may widen. In one embodiment, the first processing beam LL1 may have a pulse width that is greater than that of the second processing beam LL2. In this case, the first processing beam LL1 may reach a first depth from a surface of the processing target. That is, heat generated by the first processing beam LL1 may spread down to the first depth from the surface of the processing target. On the other hand, the second processing beam LL2 may reach a second depth that is shallower than the first depth from the surface of the processing target. A range of a region heated by the first processing beam LL1 may be greater than a range of a region heated by the second processing beam LL2.

[0114] The laser processing apparatus 1100 may adjust a pulse width of a processing beam based on a set routine or under the control of the laser monitoring apparatus 1200. Accordingly, the laser processing apparatus 1100 can adjust a processing depth of the processing target.

[0115] FIG. 10 is a schematic diagram of a beam measurement unit according to one embodiment of the present disclosure.

[0116] Referring to FIG. 10, a beam measurement unit 1150 may include an energy meter 1151, a sensor 1152, and a window 1153. The energy meter 1151 may receive a first laser beam 101 passing through the window 1153. The first laser beam 101 reaching the energy meter 1151 may be scattered. The sensor 1152 may receive a second laser beam 102 among laser beams generated through scattering. In this way, a waveform of the first laser beam 101 may be measured using the energy meter 1151. In this case, the window 1153 may have a blocking structure for preventing the first laser beam 101 from passing through the window 1153 again due to scattering or reflection. In another embodiment, the sensor 1152 may measure the first laser beam 101 that does not pass through the energy meter 1151.

[0117] Although an embodiment in which the beam measurement unit 1150 is disposed to measure a laser beam that has passed through a beam shaping unit 1130 has been described above, the beam measurement unit 1150 may also measure an individual laser beam that has not yet passed through the beam shaping unit 1130. In one embodiment, the beam measurement unit 1150 may measure laser beams L1, L2, L3, and L4 through a beam splitter disposed between a light source unit 1110 and an optical path forming unit 1120. In this case, even while a laser processing apparatus 1100 is processing a processing target, an individual laser beam may be monitored in real time, and parameters of the individual laser beam may be adjusted based on the monitoring result. That is, even without the above-described test mode, real-time monitoring and beam parameter adjustment with respect to the laser processing apparatus 1100 may be possible.

[0118] FIG. 11 is a schematic diagram illustrating a laser beam that is incident on a beam shaping unit according to one embodiment of the present disclosure.

[0119] Referring to FIG. 11, an incidence surface 1131 of a beam shaping unit 1130 may include four regions. For example, the incidence surface 1131 may include a first region R1, a second region R2, a third region R3, and a fourth region R4. In other words, the incidence surface 1131 may include quadrants including first to fourth quadrants.

[0120] The beam shaping unit 1130 may receive a plurality of laser beams. For example, the beam shaping unit 1130 may receive first to fourth laser beams. In this case, the beam shaping unit 1130 may receive the first to fourth laser beams through different regions. For example, the first laser beam may be incident on the first region R1, the second laser beam may be incident on the second region R2, the third laser beam may be incident on the third region R3, and the fourth laser beam may be received through the fourth region R4. The beam shaping unit 1130 may combine laser beams incident on different regions to generate a processing beam that travels along one optical path.

[0121] Meanwhile, a plurality of laser beams received by the beam shaping unit 1130 may be emitted at different timings. For example, the first laser beam may be emitted at a first timing, the second laser beam may be emitted at a second timing that is later than the first timing, the third laser beam may be emitted at a third timing that is later than the second timing, and the fourth laser beam may be emitted at a fourth timing that is later than the third timing.

[0122] In this case, time intervals between laser beams emitted at adjacent timings may all be the same, or there may be some laser beams with different time intervals. For example, a first time interval between the first timing and the second timing may be the same as a second time interval between the second timing and the third timing. A third time interval between the third timing and the fourth timing may be different from the first time interval and the second time interval. Specifically, the third time interval may be greater than the first time interval and the second time interval. The third time interval may be greater than the sum of the first time interval and the second time interval.

[0123] Meanwhile, the laser device 1 may be an embodiment of the laser processing apparatus 1100. The combination / split unit 20 may be an embodiment of the optical path forming unit 1120. The beam shaping unit 30 may be an embodiment of the beam shaping unit 1130. The imaging optical system 50 may be an embodiment of the imaging optical system 1140. The controller 90 may be an embodiment of the control unit 1170. The stage 60 may be an embodiment of the stage (S).

[0124] Although exemplary embodiments of the present disclosure have been shown and described, the present disclosure is not limited to the above-described specific embodiments, but it should be understood by those skilled in the art that various modifications and variations are possible without departing from the subject matter of the disclosure claimed in the accompanying claims. In addition, the modifications and variations should not be understood based on the technical spirit or prospects of the disclosure.

Claims

1.A laser processing apparatus comprising:a light source unit configured to emit a first laser beam and a second laser beam;a beam shaping unit configured to receive the first laser beam and the second laser beam and generate a processing beam from the first laser beam and the second laser beam based on an operation mode of the laser processing apparatus; anda beam measurement unit configured to measure a waveform of at least one of the first laser beam, the second laser beam, and the processing beam,wherein, when the operation mode is a processing mode, the first laser beam and the second laser beam overlap each other, and the beam measurement unit measures a waveform of the processing beam; andwhen the operation mode is a test mode, the first laser beam and the second laser beam do not overlap each other, and the beam measurement unit measures waveforms of the first laser beam and the second laser beam.2.The laser processing apparatus of claim 1, wherein the processing beam is a flat-top laser beam generated by overlapping the first laser beam and the second laser beam, andthe first laser beam and the second laser beam are emitted at different timings.3.The laser processing apparatus of claim 1, wherein, when the processing beam is abnormal in the processing mode, the laser processing apparatus enters the test mode.4.The laser processing apparatus of claim 1, further comprising an optical path forming unit disposed between the light source unit and the beam shaping unit to form optical paths of the first laser beam and the second laser beam,wherein the optical path forming unit includes a plurality of mirrors and a mirror moving unit configured to move at least one mirror of the plurality of mirrors, andthe mirror moving unit moves the at least one mirror to adjust a distance between the plurality of mirrors and adjust pulse widths of the first laser beam and the second laser beam.5.The laser processing apparatus of claim 1, wherein the light source unit emits the first laser beam at a first timing, emits the second laser beam at a second timing that is later than the first timing, and emits a third laser beam at a third timing that is later than the second timing, andthe beam shaping unit generates a first processing beam from the first laser beam and the second laser beam and generates a second processing beam from the third laser beam, wherein the first processing beam does not overlap the second processing beam.6.The laser processing apparatus of claim 5, wherein the first processing beam and the second processing beam are used in different processes.7.The laser processing apparatus of claim 1, further comprising a stage on which a processing target is placed,wherein the stage moves the processing target inside an optical path of the processing beam in the processing mode and moves the processing target outside the optical path of the processing beam in the test mode.8.The laser processing apparatus of claim 1, further comprising a communication unit configured to transmit the waveform of the laser beam measured through the beam measurement unit to a laser monitoring apparatus and receive information about a pulse width of the laser beam from the laser monitoring apparatus.9.A laser monitoring apparatus comprising:a communication interface including at least one communication circuit;a memory configured to store at least one instruction; anda processor configured to execute the at least one instruction,wherein the processor acquires and analyzes a waveform of a laser beam emitted from a laser processing apparatus,when the laser processing apparatus is in a processing mode, the processor controls the laser processing apparatus such that a first laser beam and a second laser beam overlap each other and acquires a waveform of a processing beam generated based on the first laser beam and the second laser beam, andwhen the laser processing apparatus is in a test mode, the processor controls the laser processing apparatus such that the first laser beam and the second laser beam do not overlap each other and acquires waveforms of the first laser beam and the second laser beam.10.The laser monitoring apparatus of claim 9, wherein the processor analyzes the waveform of the processing beam to determine whether the processing beam is abnormal, andwhen it is determined that the processing beam is abnormal, the processor controls the laser processing apparatus to enter the test mode.11.The laser monitoring apparatus of claim 10, wherein the processor compares the waveform of the processing beam with a pre-stored waveform to determine whether the processing beam is abnormal.12.The laser monitoring apparatus of claim 9, wherein, when the laser processing apparatus is in the test mode, the processor identifies a laser beam that is abnormal between the first laser beam and the second laser beam, obtains a value for adjusting a parameter of the identified laser beam, and controls the laser processing apparatus based on the obtained value.13.The laser monitoring apparatus of claim 12, wherein the parameter is an emission timing, a pulse width, a pulse height, a pulse area, or a pulse rising time.14.A method of operating a laser processing apparatus, the method comprising:emitting, by a light source unit, a first laser beam and a second laser beam;generating, a beam shaping unit, a processing beam from the first laser beam and the second laser beam based on an operation mode of the laser processing apparatus; andmeasuring, by a beam measurement unit, a waveform of at least one of the first laser beam, the second laser beam, and the processing beam,wherein, when the operation mode is a processing mode, the first laser beam and the second laser beam overlap each other, and a waveform of the processing beam is measured, andwherein, when the operation mode is a test mode, the first laser beam and the second laser beam do not overlap each other, and waveforms of the first laser beam and the second laser beam are measured.15.The method of claim 14, wherein the processing beam is a flat-top laser beam generated by overlapping the first laser beam and the second laser beam, andthe first laser beam and the second laser beam are emitted at different timings.

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