Operation method of a laser beam irradiation device for semiconductor complete cutting via a plurality of laser beams

Abstract

To provide a method for operating a laser beam irradiation device for semiconductor processing, which can improve chip performance by vibrating a laser beam so as to reduce accumulation of heat energy by laser condensation.SOLUTION: A method for operating a laser beam irradiation device for semiconductor processing includes the steps of: outputting a first laser beam so as to perform pre-processing for cutting an irradiated body with mass production quality; outputting a second laser beam for cutting the irradiated body along a path where the pre-processing on the basis of the first laser beam is performed; and outputting the first laser beam at an angle vertical to a processing direction without vibrating differently from the second laser beam, and outputting the second laser beam so as to have a first angle vertically to the processing direction, and vibrating the second laser beam in the processing direction.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The technical idea of the present disclosure relates to a laser beam irradiation device for semiconductor complete cutting and an operation method thereof, and more specifically, to a laser beam irradiation device for preventing optical damage to semiconductor elements and an operation method thereof.

Background Art

[0002] Due to the leapfrog development of the electronics industry and the requirements of users, electronic devices are becoming smaller, more highly integrated, and larger in area. Along with this, the size of semiconductor elements included in electronic devices has entered the fine region in nanometer units.

[0003] As a semiconductor processing method related to the present disclosure, dicing, which cuts and separates a large-area wafer into a plurality of chips as a kind of cutting process, a grinding process for thinning the thickness of the wafer, and a grooving process for creating grooves for forming conductive wiring are included.

[0004] In relation to dicing, blade dicing, a substrate cutting method using a thin cutting blade formed of fine diamond, is used. However, in the case of the substrate cutting process by the cutting blade, chipping occurs on the front and back surfaces of the substrate, and the performance of the chips divided by this chipping may be reduced.

[0005] In still other dicing processes, stealth dicing, which concentrates laser light in a local area to form internal cracks for cutting, is used. However, since the laser light of stealth dicing has an extremely high peak power, cracks on the semiconductor surface may also be caused during the process of forming internal cracks, and accordingly, the performance of the chips may be reduced.

Summary of the Invention

Problems to be Solved by the Invention

[0006] The problem to be solved by the technical idea of the present disclosure is to provide a laser beam irradiation device for semiconductor processing and an operation method thereof, which can improve chip performance by vibrating a laser beam in order to reduce the accumulation of thermal energy due to laser focusing.

Means for Solving the Problem

[0007] In order to achieve the above object, in a laser beam irradiation device for semiconductor processing according to one aspect of the technical idea of the present disclosure, a laser beam is advanced in a processing direction so as to perform semiconductor processing, and the laser beam is vibrated so as to have a constant amplitude in a vibration direction different from the processing direction, and a laser beam output unit for vibrating the laser beam and a focusing lens for imaging the laser spot that advances in the processing direction and vibrates in the vibration direction on the semiconductor can be included.

[0008] Further, the laser beam output unit can output a first laser along the processing direction to the semiconductor in one processing, and output a second laser having an incident angle different from that of the first laser along the processing direction.

[0009] Further, the laser beam output unit can include a first laser beam output unit that outputs the first laser and a second laser beam output unit that outputs the second laser that forms a cut surface on the semiconductor in order to perform preprocessing for cutting the semiconductor with good processing quality.

[0010] On the other hand, the laser beam output unit can further include a laser oscillation unit that oscillates and outputs a laser beam and a vibration unit that physically vibrates an optical element so as to vibrate the laser beam irradiated from the laser oscillation unit in the vibration direction.

[0011] Further, the laser oscillation unit and the focusing lens are fixed without vibration, and the optical element can perform single vibration by the driving force of the motor of the vibration unit.

[0012] Further, the optical element includes a horizontal mirror, and the motor can be at least one of an ultrasonic motor and a resonance motor.

[0013] Further, it can include an input unit that receives operation instructions for semiconductor processing and a control unit that controls a vibration unit so as to apply a sine wave input to the motor in a first mode and apply a triangular wave or a rectangular wave to the motor in a second mode based on the operation instructions.

[0014] Further, the first mode can be a user mode selected by a user who assigns a priority to the vibration speed of the laser beam, and the second mode can be a user mode selected by a user who assigns a priority to the vibration width of the laser beam.

[0015] On the other hand, the optical element includes a pair of polygon mirrors each having a large number of reflection surfaces, and the pair of polygon mirrors can rotate in different directions.

[0016] The semiconductor includes a semiconductor substrate, and the focusing lens can output the laser beam so that the laser beam has a predetermined incident angle in a direction perpendicular to the plane of the semiconductor.

[0017] The incident angle substantially coincides with a right angle, and the laser beam output unit can vibrate the laser beam by a vibration width in the vibration direction so as to correspond to a distance determined by the line width of the semiconductor substrate.

Advantages of the Invention

[0018] According to an exemplary embodiment of the present disclosure, different from stealth dicing, by vibrating the laser beam without accumulating thermal energy in a local small area, the thermal energy can be dispersed, thereby preventing the destruction and deformation of the semiconductor material.

[0019] According to an exemplary embodiment of the present disclosure, through pre-processing by a preceding laser, it is possible to achieve quality assurance of an irradiated object and a mass-produced product using the same, and it is possible to achieve mass production quality by complete cutting with a subsequent laser.

[0020] According to an exemplary embodiment of the present disclosure, semiconductor processing can be performed precisely by easily determining processing parameters (e.g., line width) using the diameter of a laser spot adjusted by a lens, and the defect rate can be reduced and the yield can be increased.

[0021] According to an exemplary embodiment of the present disclosure, the process yield can be increased by sucking out ejecta (e.g., dust, particles, debris) generated during the process of processing a semiconductor by a vibrating laser beam.

[0022] According to an exemplary embodiment of the present disclosure, a customized product that meets the needs of a producer can be obtained by adjusting the incident angle of a vibrating laser beam to an acute angle, a right angle, or an obtuse angle.

Brief Description of Drawings

[0023]

Figure 1

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Figure 2b

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Embodiments for Carrying Out the Invention

[0024] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0025] FIG. 1 is a conceptual diagram for explaining a laser beam irradiation device 10 according to an exemplary embodiment of the present disclosure.

[0026] Referring to FIG. 1, the laser beam irradiation device 10 can include an input unit 100, a control unit 200, a laser beam output unit 300, and a focusing lens 400. The laser beam output unit 300 can further include a laser oscillation unit 310, a vibration unit 320, and an optical element 330.

[0027] The laser beam irradiation device 10 can form a laser spot LS on the irradiated object ST by outputting a laser beam.

[0028] The irradiated object ST can include a semiconductor substrate and a wafer. For convenience of explanation, hereinafter, the irradiated object ST can be described together with a semiconductor, a semiconductor substrate, or a semiconductor wafer. In this case, the substrate can be processed in various ways by the thermal energy of the laser beam, and the various ways can include dicing processing in which the laser beam irradiation device 10 cuts and separates a large-area wafer into a plurality of chips, grinding processing in which the thickness of the wafer is thinned, and grooving processing in which grooves are formed for forming conductive wiring.

[0029] Also, the irradiated object ST can include a semiconductor film (for example, an oxide film). For example, the laser beam irradiation device 10 can anneal the semiconductor film.

[0030] Hereinafter, "processing" can mean a process of causing physical deformation to the irradiated object ST by the laser beam of the laser beam irradiation device 10, and the technical idea of the present disclosure is not limited to the above-described examples.

[0031] According to an exemplary embodiment of the present disclosure, the laser beam irradiation device 10 can vibrate the laser beam in order to reduce the accumulation of thermal energy condensed by the laser spot LS.

[0032] Specifically, the laser beam irradiation device 10 can advance a laser beam in the processing direction so as to perform processing on the irradiated object ST. At the same time, the laser beam irradiation device 10 can vibrate the laser beam so as to have a certain amplitude (processing amplitude) in a vibration direction different from the processing direction. Thereby, before the irradiated object ST is deformed due to excessive accumulation of the thermal energy of the first laser spot LS1, the defective rate of the irradiated object ST can be reduced by vibrating at the second laser spot LS2.

[0033] On the other hand, as will be described later with reference to FIG. 3, the laser beam irradiation device 10 can vibrate the laser beam so as to have a certain amplitude in the same vibration direction as the processing direction. By the laser beam having the same vibration direction as the processing direction, the laser beam irradiation device 10 can suck out or remove the ejecta (for example, dust, particles, debris) generated in the process of processing the irradiated object ST to the outside of the processing area based on the vibrating laser beam. Thereby, a decrease in yield due to the ejecta can be prevented.

[0034] The input unit 100 can receive an operation command of the user. As an example, the operation command can include a command for the user to determine the line width to be dug on the irradiated object ST, and as another example, the operation command can include a command for controlling the processing speed of the irradiated object ST.

[0035] The input unit 100 can be selected by the user from among the first mode and the second mode. The first mode can be a user mode in which a priority is assigned to the vibration speed of the laser beam, and the second mode can be a user mode in which a priority is assigned to the vibration width of the laser beam. The processing methods in the first mode and the second mode will be described later together with the control unit 200.

[0036] On the one hand, the input unit 100 can be embodied by a device (e.g., a keyboard) or software (input user interface) that can receive the user's operation commands and transmit them to the control unit 200. Alternatively, the input unit 100 can be the input interface of an operating system (O / S). Without being limited to this, the input unit 100 can include input means in various forms of hardware, software, or firmware.

[0037] The control unit 200 can output an oscillation signal SO to control the laser oscillation unit 310.

[0038] The laser oscillation unit 310 can include semiconductor devices or semiconductor components, or all types of oscillation devices that can process the irradiated object ST included therein. For example, the laser oscillation unit 310 can include lasers with output powers ranging from several hundred watts to several hundred kilowatts. The oscillation signal SO can control the overall operation of the laser oscillation unit 310.

[0039] The control unit 200 can output a vibration signal SV to control the vibration unit 320. The vibration signal SV can include information regarding the vibration amplitude, vibration speed, and input waveform. For example, the vibration unit 320 can include a resonance motor. Hereinafter, the resonance motor can mean a driving device in which the vibrator vibrates resonantly and can have a higher vibration frequency than a galvo motor.

[0040] The control unit 200 can apply different input waveforms to the vibration unit 320 based on a plurality of user modes including a first mode and a second mode. Here, the input waveform can include the waveform of the electrical signal applied to drive the motor.

[0041] The control unit 200 can output a vibration signal SV that applies a sine wave input to the motor of the vibration unit 320 in the first mode based on an operation command. The motor to which the sine wave input is applied can maximize the vibration speed of the laser beam. That is, although the accuracy of the vibration amplitude is lower than in the second mode, the maximum vibration speed (frequency) at which the laser beam can vibrate can be further increased.

[0042] Also, the control unit 200 can output the vibration signal SV so as to apply a triangular wave or a rectangular wave to the motor of the vibration unit 320 in the second mode based on an operation command. The motor to which the triangular wave or rectangular wave input is applied can precisely determine the vibration amplitude. That is, although the vibration speed is lower than in the first mode, the laser beam can vibrate with a width closer to the target vibration amplitude.

[0043] The laser beam output unit 300 can include a laser oscillation unit 310 that oscillates and outputs a laser beam. The laser oscillation unit 310 can process the irradiated object ST by outputting the oscillated laser to the optical element 330. The vibration unit 320 can vibrate the optical element 330 so as to vibrate the laser beam irradiated from the laser oscillation unit 310 in the vibration direction. This is to vibrate the laser beam input to the focusing lens 400.

[0044] As an example, the irradiated laser beam can be a single ray, and as another example, the laser beam irradiation device 10 may output a plurality of laser beams. When a plurality of laser beams are output, the laser oscillation unit 310 can include a plurality of oscillation modules for outputting a plurality of laser beams.

[0045] In the process of vibrating the laser beam, only a part of the configuration of the laser beam output unit 300 can vibrate. In other words, the laser oscillation unit 310 and the focusing lens 400 are fixed without vibration, and the optical element 330 can perform single vibration by the driving force of the motor of the vibrating unit 320. Compared with the vibration of the laser oscillation unit 310 and the focusing lens 400, the processing of the irradiated object ST can be precisely performed, and the accumulation of heat can be prevented.

[0046] The vibrating unit 320 can determine the vibration amplitude and vibration speed of the optical element 330. For example, the motor of the vibrating unit 320 can be mechanically directly or indirectly connected to the optical element 330. Since the optical element 330 outputs the laser beam output from the laser oscillation unit 310 to the focusing lens 400, the vibrating unit 320 can determine the vibration amplitude and vibration speed of the laser beam by controlling the optical element 330.

[0047] The optical element 330 can include a mirror. That is, the optical element 330 can reflect the laser beam output from the laser oscillation unit 310 and output it to the focusing lens 400. The vibrating unit 320 can be at least one of an ultrasonic motor and a resonance motor. This is because a general motor using electromagnetic force cannot achieve the technical idea of the present disclosure for preventing excessive accumulation of thermal energy applied to the irradiated object ST.

[0048] The focusing lens 400 can output the laser beam so that the laser beam has a predetermined incident angle in a direction perpendicular to the plane of the irradiated object ST. The predetermined incident angle can be 0 degrees (zero degree) or more and 90 degrees or less.

[0049] The focusing lens 400 can be an objective lens, a short-focus lens, or an F-theta lens. The focusing lens 400 can be selected one according to the processing method and the requirements of the user among the objective lens, the short-focus lens, and the F-theta lens. This will be described later.

[0050] The laser beam irradiation device 10 according to an exemplary embodiment of the present disclosure can improve the processing quality and speed by vibrating rapidly in a vibration direction different from the processing direction. In comparison, the conventional technology had the disadvantage of a decrease in processing quality and speed.

[0051] FIGS. 2a and 2b are for explaining a processing method of the laser beam irradiation device 10 according to an exemplary embodiment of the present disclosure.

[0052] Referring to FIGS. 2a and 2b, the laser beam irradiation device 10 can include a first laser beam output unit 300a and a second laser beam output unit 300b, each of which may correspond to the laser beam output unit 300 described above with reference to FIG. 1. On the other hand, the laser beam irradiation device 10 can include a first focusing lens 400a and a second focusing lens 400b, each of which may correspond to the focusing lens 400 described above with reference to FIG. 1.

[0053] According to an exemplary embodiment of the present disclosure, the laser beam irradiation device 10 outputs a first laser along the processing direction to the irradiated object ST in one processing, and can output a second laser having an incident angle different from that of the first laser along the processing direction.

[0054] According to an exemplary embodiment of the present disclosure, the second laser beam output unit 300b can output a second laser for cutting the irradiated object ST. For example, the second laser can form a cut surface on the irradiated object ST. The first laser beam output unit 300a can output a first laser to perform pre-processing for cutting the irradiated object ST with mass production quality. Here, the mass production quality may refer to the target quality that the processing entity intends to achieve, and can include, for example, cross-sectional uniformity, cutting speed, cutting size, and line width. Also, for example, when the irradiated ST is a wafer, the first laser beam output unit 300a can output a first laser for the purpose of removing a compound on the semiconductor surface.

[0055] According to an exemplary embodiment of the present disclosure, the second laser beam output unit 300b can output a second laser along the path where the first laser beam output unit 300a has performed pre-processing. That is, the second laser beam output unit 300b can process (e.g., cut) the irradiated object ST in the area prepared by the first laser beam output unit 300a. In this sense, the first laser can be referred to as the preceding laser, and the second laser can be referred to as the subsequent laser.

[0056] According to an exemplary embodiment of the present disclosure, the first laser beam output unit 300a can output a laser with a wavelength lower than that of the second laser beam output unit 300b. According to experiments, when the first laser beam output unit 300a outputs a first laser beam having a wavelength of 515 nm or more and 532 nm or less, or 266 nm or more and 355 nm or less, the surface of the irradiated object ST can be modified without protrusions. This is because substances on the surface of semiconductor wafers such as metals, ceramics, and compounds are materials that easily absorb the first laser beam of the aforementioned wavelength.

[0057] According to an exemplary embodiment of the present disclosure, the first laser beam output unit 300a may have a higher intensity than the second laser beam output unit 300b but a lower average output. According to experiments, when the average output of the preceding laser output by the first laser beam output unit 300a is high, the irradiated object ST may be processed to an excessive depth. This is because it may interfere with ensuring the processing quality when the second laser beam output unit 300b actually performs processing (e.g., cutting). Therefore, the first laser (i.e., the preceding laser) may have a higher intensity than the second laser (i.e., the subsequent laser) but a lower average output.

[0058] Referring to FIG. 2a, the first laser beam output unit 300a can output a first laser to the irradiated object ST in the vertical direction of the irradiated object ST, and the second laser beam output unit 300b can output a second laser so as to have a first angle with respect to the processing direction. Here, the first angle θa can be more than 90 degrees and less than 180 degrees.

[0059] In addition, the first laser beam output unit 300a can output the first laser in the vertical direction of the irradiated object ST along the processing direction without vibrational movement, and the second laser beam output unit 300b can output the second laser that vibrates in the processing direction.

[0060] Referring to FIG. 2b, the first laser beam output unit 300a can output the first laser so as to have a second angle θb with respect to the processing direction. Here, the second angle θb can be more than 0 degrees and less than 90 degrees. In the case of the irradiated object ST that is sensitive and vulnerable to the laser beam, by outputting the first laser at an acute incident angle, the quality of processing the irradiated object ST by the second laser beam output unit 300b can be further improved. Also, compared with the first laser having a vertical incident angle, the first laser having an acute incident angle can obtain the target processing quality even when output to the irradiated object ST at a higher output. Therefore, surface removal and depth processing can be more easily performed at one time with more energy.

[0061] Also, different from what was described above with reference to FIG. 2a, the first laser beam output unit 300a can output a first laser that vibrates, that is, vibrates along the processing direction. For example, when vibrating the first laser, when processing the irradiated object ST made of a thick material, more effective and rapid processing (for example, cutting) can be performed in that the cutting process is performed using both the first laser and the second laser. However, it is not limited to this, and the first laser beam output unit 300a can output the first laser that does not vibrate while having the second angle θb.

[0062] Referring to FIGS. 2a and 2b, through the continuous cutting operations of a preceding laser (i.e., the first laser) and a subsequent laser (i.e., the second laser), full cutting of an irradiated object ST (e.g., a semiconductor wafer) can be achieved. In other words, conventionally, when attempting to fully cut an irradiated object with a single laser, mass production quality could not be achieved due to the excessive output of the laser beam (e.g., FIGS. 12(a) and 13(a)). However, according to the exemplary embodiments of the present disclosure, through the preprocessing by the preceding laser, quality assurance of the irradiated object ST and mass production results using the same can be achieved, and mass production quality can be achieved by full cutting with the subsequent laser. Also, by using the preceding laser and the subsequent laser, the output of each laser can be reduced, thereby preventing heat accumulation in the irradiated object ST and preventing material deformation of the irradiated object ST.

[0063] FIG. 3 is for explaining conventional blade dicing and stealth dicing.

[0064] Referring to FIG. 3(a), a blade dicing apparatus rotates a thin cutting blade formed of fine diamond at high speed. That is, the blade dicing apparatus cuts an object using the saw blade formed on the cutting blade.

[0065] In this process, the cutting blade can irregularly peel off the cutting surface on the front or back surface of the substrate where the blade is located during the process of cutting the object (e.g., the substrate). Also, chipping may occur on the substrate during the process of the object being peeled off. This can be a major factor in reducing the performance of the chips that have been diced and divided.

[0066] However, the method of irradiating a laser beam irradiates a laser beam with a strong output to a local part, so the factors causing the above-mentioned performance degradation do not occur.

[0067] Referring to the reverse side, (b) of FIG. 3, the stealth dicing device can concentrate the laser beam on a local area of the object to form internal cracks for cutting. The object can be separated along the cracks formed in a certain pattern. During the separation process, an irregular cut surface may be formed on the cut surface of the area adjacent to the crack. Also, since the laser beam of stealth dicing has extremely high peak power, unwanted cracks may further occur on the semiconductor surface, and accordingly, the performance of the chip may deteriorate.

[0068] However, according to the exemplary embodiments of the present disclosure, since the irradiated object ST is completely cut using a laser beam, there is no need to go through a separate peeling process compared to stealth dicing, and accordingly, factors causing performance degradation can be removed. Also, even if it has a high peak power like stealth dicing, the time the laser stays in a specific area can be epoch-makingly reduced by vibration compared to stealth dicing, so deformation of the irradiated object ST due to heat energy accumulation can be prevented.

[0069] FIG. 4 is for explaining a method of vibrating a laser beam according to an exemplary embodiment of the present disclosure. Hereinafter, it will be described in chronological order along (a) to (c) of FIG. 4.

[0070] Referring to (a) to (c) of FIG. 4, the laser beam irradiation device 10 can output the laser beam LB3 to different positions of the focusing lens 400 by vibrating the laser beam LB3. For convenience of explanation, different reference numerals are assigned to the laser beams LB31 to LB33 in the first aspect, the second aspect, and the third aspect, but they can be one laser beam output from the same laser oscillation unit 310. However, it is not limited thereto, and the laser beams LB31 to LB33 may be laser beams from different oscillation units.

[0071] Describing it in a time series, the laser beam irradiation device 10 first outputs the laser beam LB31 to the edge region of the focusing lens 400. After that, due to vibration, the laser beam irradiation device 10 outputs the laser beam LB32 to the central region of the focusing lens 400. After this, due to vibration, the laser beam irradiation device 10 outputs the laser beam LB33 to the edge region on the side opposite to the edge region in the first aspect.

[0072] The laser beam irradiation device 10 can form laser spots LS on different regions a1 to a3 of the irradiated object ST respectively. The laser beam irradiation device 10 can process each of the regions a1 to a3 that are separated by the vibration distance (processing width, line width) in the y-axis direction while not being greatly separated in the x-axis direction. Here, the vibration distance can correspond to the line width of the conductor. That is, the laser beam irradiation device 10 can vibrate by the line width in the y-axis direction.

[0073] According to an exemplary embodiment of the present disclosure, the laser beam irradiation device 10 can vibrate the laser beam LB3 so that the laser spot LS stays in a local region (for example, a1) only for a time during which no material deformation occurs according to a preset quality standard.

[0074] As an example, the control unit 200 can transmit the vibration signal SV so that the vibration unit 320 has at least one of vibration speeds exceeding 0 and less than or equal to 20 kHz. At this time, when the control unit 200 outputs a vibration signal SV having a vibration speed that is the same as or greater than 1 kHz, the vibration unit 320 can be implemented by one of an ultrasonic motor and a resonance motor.

[0075] As another example, the control unit 200 can transmit the vibration signal SV so that the vibration unit 320 has at least one of vibration speeds exceeding 0 and less than or equal to 10 MHz.

[0076] According to an embodiment, the laser beam irradiation device 10 receives an input through the input unit 100 that the object ST to be irradiated is a wafer made of a first material, and the control unit 200 can control the laser spot LS to stay in a local area (for example, a1) for a time corresponding to the first frequency by transmitting an oscillation signal SV including the first frequency.

[0077] FIG. 5 is for explaining the vibration method, focusing lens, and processing method of the laser beam irradiation device according to an exemplary embodiment of the present disclosure.

[0078] According to an embodiment of the present disclosure, the laser beam irradiation device 10 can form a cutting surface having a width corresponding to the vibration distance in the y-axis direction by the vibrating laser beam LB4 that has passed through the focusing lens 400. That is, the laser beam irradiation device 10 can perform a dicing process.

[0079] According to another embodiment of the present disclosure, the laser beam irradiation device 10 can form a groove having a width corresponding to the vibration distance in the y-axis direction. That is, the laser beam irradiation device 10 can perform a grooving process.

[0080] According to still another embodiment of the present disclosure, the laser beam irradiation device 10 can perform a grinding process by vibrating the laser beam LB4 greatly in the y-axis direction.

[0081] Hereinafter, the vibration method of the laser beam irradiation device 10 will be described together with FIGS. 6 to 8, and mirror vibration, polygon vibration, and light source vibration will be described.

[0082] The focusing lens 400 will be described together with FIG. 9, and each case of the objective lens, short-focus lens, and F-theta lens will be described.

[0083] FIG. 6 is for explaining mirror vibration among the vibration methods according to an exemplary embodiment of the present disclosure.

[0084] Referring to FIG. 6, the vibrating part 320 can include a motor 321, and the motor 321 can be at least one of an ultrasonic motor and a resonance motor. Also, the optical element 330 can include a horizontal mirror 331.

[0085] According to an exemplary embodiment of the present disclosure, the horizontal mirror 331 is mechanically connected to the motor 321, the driving force of the motor 321 is transmitted to the mirror, and the horizontal mirror 331 can perform single vibration. At this time, the frequency of the single vibration can be substantially the same as the vibration speed at which the laser beam irradiation device 10 vibrates in a vibration direction different from the processing direction.

[0086] According to an exemplary embodiment of the present disclosure, the optical element 330 can vibrate in a direction parallel to the focusing lens 400. Accordingly, the laser beam can reciprocally vibrate at a point that is origin-symmetric with respect to the center point of the focusing lens 400.

[0087] According to an exemplary embodiment of the present disclosure, the optical element 330 can vibrate in the direction in which the laser output from the laser oscillation unit 310 is incident on the optical element 330. At this time, the optical element 330 can be a plane mirror that reflects the laser output from the laser oscillation unit 310 to the focusing lens 400.

[0088] According to an exemplary embodiment of the present disclosure, the motor 321 can be a vibration motor such as an ultrasonic motor and a resonance motor. The vibration motor can generate a driving force by generating a high vibration frequency inside the motor 321. The driving force of the high vibration frequency can be transmitted to the horizontally connected mirror 331, which is structurally directly or indirectly coupled, through the transmission part of the motor 321.

[0089] Preferably, the motor 321 can generate a vibration frequency that is the same as or greater than 1 kHz and the same as or less than 20 kHz. That is, at least one of the ultrasonic motor and the resonance motor can vibrate the laser beam at a frequency that is the same as or greater than 1 kHz and the same as or less than 20 kHz, so as to increase the process yield by sucking out the ejecta (e.g., dust, particles, debris) generated during the process of processing the semiconductor by the vibrating laser beam. The generally used linear actuator motor cannot achieve the effects according to the exemplary embodiments of the present disclosure with a low vibration frequency of less than 1 kHz. However, through a number of experiments, it has been confirmed that while the laser beam sucks out the ejecta at a frequency that is the same as or greater than 1 kHz and the same as or less than 20 kHz, the thermal deformation of the irradiated object ST is significantly reduced.

[0090] Referring to FIG. 6(a), in the first aspect, the horizontal mirror 331 can be located at point b1. Subsequently, referring to FIG. 6(b), due to the driving force (vibration) of the motor 321, in the second aspect, the horizontal mirror 331 can be located at point b3 via point b2. After that, due to the driving force (vibration) of the motor 321, the horizontal mirror 331 can reciprocate from point b3 to point b1.

[0091] That is, the laser beam irradiation device 10 according to the exemplary embodiment of the present disclosure can output a laser beam that vibrates in the vibration direction to the irradiated object ST by utilizing the driving force of the motor 321 and the vibration of the horizontal mirror 331 based thereon.

[0092] FIG. 7 is for explaining polygon vibration among the vibration methods according to the exemplary embodiments of the present disclosure.

[0093] Referring to FIG. 7, the optical element 330 includes a pair of polygon mirrors 332, and the pair of polygon mirrors 332 can include a first polygon mirror 332a and a second polygon mirror 332b having a plurality of reflecting surfaces.

[0094] According to an exemplary embodiment of the present disclosure, the laser oscillation unit 310 may include a plurality of oscillation modules. For example, the laser oscillation unit 310 may output a plurality of laser beams including a first laser beam i_a and a second laser beam i_b. The laser oscillation unit 310 may output the first laser beam i_a to the first polygon mirror 332a and output the second laser beam i_b to the second polygon mirror 332b.

[0095] The first polygon mirror 332a may rotate in a first direction d1_a, and the second polygon mirror 332b may rotate in a second direction d1_b which is opposite to the first direction d1_a. As an example, the vibration unit 320 may be implemented as a rotary motor and can rotate the first polygon mirror 332a and the second polygon mirror 332b in different directions from each other. As another example, the vibration unit 320 may be implemented as a vibration motor, and the vibration unit 320 may output a driving force (vibration) to the plurality of polygon mirrors so that the first polygon mirror 332a and the second polygon mirror 332b vibrate in opposite phases to each other.

[0096] According to an exemplary embodiment of the present disclosure, when the optical element 330 includes a pair of polygon mirrors 332, the reflected output laser beams o_a, o_b may be output to the irradiated object ST. At this time, the reflected output laser beams o_a, o_b may vibrate in different directions from each other.

[0097] Also, the reflected output laser beams o_a and o_b can vibrate in a single direction respectively. As an example, the first output laser beam o_a can vibrate in the order of the first point p1_a, the second point p2_a, the third point p3_a, the first point p1_a, the second point p2_a... of the irradiated object ST. The second output laser beam o_b can vibrate in the order of the fourth point p1_b, the fifth point p2_b, the sixth point p3_b, the fourth point p1_b, the fifth point p2_b... That is, when the output laser beams o_a and o_b reach the third point p3_a and the sixth point p3_b respectively, they return to the first point p1_a and the fourth point p1_b. This is due to the shape of the polygon mirror.

[0098] That is, according to an exemplary embodiment of the present disclosure, when the optical element 330 includes a pair of polygon mirrors 332, the laser beam irradiation device 10 can process the irradiated object ST by outputting output laser beams o_a and o_b that vibrate in a single vibration in different directions to the irradiated object ST. At this time, the direction of single vibration may be different from the traveling direction in which the processing of the irradiated object ST proceeds.

[0099] On the other hand, the output laser beams o_a and o_b can be output to the irradiated object ST through the focusing lens 400.

[0100] FIG. 8 is for explaining the light source vibration among the vibration methods according to an exemplary embodiment of the present disclosure.

[0101] Referring to FIGS. 8(a) and 8(b), the optical element 330 can include a fixed horizontal mirror 333.

[0102] According to an exemplary embodiment of the present disclosure, the laser oscillation unit 310 can be mechanically directly or indirectly connected to the vibration unit 320 to transmit a driving force (vibration). Different from FIG. 5, the fixed horizontal mirror 333 and the focusing lens 400 can be fixed without vibration, and the laser oscillation unit 310 can vibrate by the vibration unit 320. As an example, the laser oscillation unit 310 can perform single vibration in a reciprocating manner from point d1 to point d3 and then from point d3 to point d1.

[0103] According to an exemplary embodiment of the present disclosure, due to the vibration of the laser oscillation unit 310, the irradiated object ST can be processed in the vibration direction from point a1 to point a3.

[0104] FIG. 9 is for explaining a focusing lens according to an exemplary embodiment of the present disclosure.

[0105] Referring to FIG. 9(a), the focusing lens 400 can be implemented by an f-theta lens 401, and FIG. 9(b) is for explaining an achromatic lens 402. Different from the achromatic lens 402, the f-theta lens 401 may not cause an upper surface curvature phenomenon.

[0106] The laser beam irradiation device 10 according to an exemplary embodiment of the present disclosure can be used for semiconductor processing in nanoscale units. When an upper surface curvature phenomenon occurs like the achromatic lens 402, it may be difficult to derive the effects of the invention according to the technical idea of the present disclosure in terms of the inability to finely adjust the vibration amplitude. Accordingly, the laser beam irradiation device 10 can precisely adjust the vibration amplitude by using the f-theta lens 401.

[0107] In addition, the focusing lens 400 according to an exemplary embodiment of the present disclosure can include a short focal length lens, a singlet lens, and a bi-convex lens.

[0108] On the one hand, the focusing lens 400 according to an exemplary embodiment of the present disclosure may include an objective lens. At this time, the objective lens can have a magnification of 5 times or more and 100 times or less. The objective lens is optimized to form a fine laser spot LS compared to the f-theta lens 401 described above. According to experiments, when the objective lens among the above-described lenses is implemented as the focusing lens 400, the diameter of the laser spot LS can be formed to be the smallest and clearest. This will be described in connection with FIG. 9.

[0109] FIG. 10 is for explaining the vibration direction and the processing direction based on the determination of the processing method according to an exemplary embodiment of the present disclosure.

[0110] Referring to FIG. 10(a), the laser beam irradiation device 10 can output a laser beam along the processing direction while vibrating widely in the horizontal direction.

[0111] Accordingly, when the irradiated object ST is implemented as a wafer, the laser beam irradiation device 10 can perform at least one of grooving, scribing, removing, and grinding.

[0112] Referring to FIG. 10(b), the laser beam irradiation device 10 can output a laser beam along the horizontal direction while vibrating narrowly and deeply in the vertical direction (perpendicular direction).

[0113] Accordingly, when the irradiated object ST is implemented as a wafer, the laser beam irradiation device 10 can perform dicing processing.

[0114] FIG. 11 is for explaining the processing direction and the incident angle according to an exemplary embodiment of the present disclosure.

[0115] Referring to FIGS. 11(a), 11(b), and 11(c) respectively, the laser beam irradiation device 10 can perform forward machining, perpendicular (vertical direction) machining, and reverse machining according to the incident angle. In the case of forward machining, the laser beam irradiation device 10 can output a laser beam to the irradiated object ST at an acute angle θ1 with respect to the machining direction. In the case of perpendicular (vertical direction) machining, the laser beam irradiation device 10 can output a laser beam to the irradiated object ST at a right angle θ2 with respect to the machining direction. In the case of reverse machining, the laser beam irradiation device 10 can output a laser beam to the irradiated object ST at an obtuse angle θ3 with respect to the machining direction. Since the uses and utilities of each machining method have been described above, they will be omitted.

[0116] According to an exemplary embodiment of the present disclosure, the depth of penetration of the laser beam into the irradiated object ST may vary depending on the incident angle of the laser beam. For example, when attempting to engrave by a first depth, the laser beam irradiation device 10 can perform perpendicular machining. When attempting to engrave by a second depth shallower than the first depth, the laser beam irradiation device 10 can perform forward machining or reverse machining.

[0117] FIGS. 12 and 13 are electron microscope images for explaining the quality of semiconductor processing results according to an exemplary embodiment of the present disclosure together with a comparative example.

[0118] FIG. 12(a) is a cross-sectional view of the irradiated object ST diced according to a comparative example, and FIG. 12(b) is a cross-sectional view of the irradiated object ST diced according to an exemplary embodiment of the present disclosure.

[0119] According to the comparative example, it can be confirmed that inhomogeneous regions occur on both the surface and the cross-section, resulting in deteriorated processing quality.

[0120] However, according to an exemplary embodiment of the present disclosure, a smooth cross-section can be confirmed, and it can be confirmed that no cracking phenomenon due to the laser occurs on the surface and the processing quality is excellent.

[0121] (a) and (b) of FIG. 13 are images of a semiconductor processed only by line width according to a comparative example and an exemplary embodiment of the present disclosure, respectively, taken in the vertical direction.

[0122] According to the comparative example, it can be confirmed that by irradiating a strong laser beam in the processing direction without vibration, the irradiated object was damaged up to a portion that is not the target area due to the strong heat of the laser.

[0123] However, according to the exemplary embodiment of the present disclosure, since a laser beam having an appropriate intensity is irradiated in the processing direction while vibrating in the vibration direction, laser damage cannot be found in portions other than the target area.

[0124] As described above, exemplary embodiments have been disclosed in the drawings and the specification. Although specific terms have been used in this specification to describe the embodiments, these are used merely for the purpose of explaining the technical idea of the present disclosure and are not used for limiting the meaning or the scope of the present disclosure described in the claims. Therefore, those having ordinary knowledge in the technical field will understand that various modifications and equivalent other embodiments will be possible hereafter. Therefore, the true technical protection scope of the present disclosure should be determined by the technical idea of the appended claims.

Claims

1. In an operating method of a laser beam irradiation apparatus for semiconductor processing, outputting a first laser beam to perform preprocessing for cutting an object to be irradiated with mass production quality; outputting a second laser beam for cutting the object to be irradiated along a path on which the preprocessing based on the first laser beam has been performed; and outputting the first laser beam at an angle perpendicular to the processing direction, not vibrating unlike the second laser beam, outputting the second laser beam to have a first angle perpendicular to the processing direction, and vibrating the second laser beam in the processing direction. The operating method includes these steps.

2. The operating method according to claim 1, wherein the first laser beam has a wavelength lower than that of the second laser beam.

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