Laser beam irradiation equipment for complete cutting of semiconductors by physically vibrating optical elements

Abstract

To provide a laser beam irradiation device for semiconductor processing and a method of operating the same, which are able to improve chip performance by vibrating a laser beam so as to lower the accumulation of thermal energy due to laser focusing.SOLUTION: A laser beam irradiation device for semiconductor processing in accordance with an aspect of the technical concept of the present disclosure may comprise: a laser beam output unit that causes a laser beam to travel in a processing direction so as to carry out processing of a semiconductor, and vibrates the laser beam so as to have a constant amplitude in a vibration direction different from the processing direction; and a focusing lens that forms on the semiconductor an image of the laser spot traveling in the processing direction and vibrating in the vibration direction.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The technical idea of ​​the present disclosure relates to a laser beam irradiation device and an operating method thereof for completely cutting semiconductors, and more particularly to a laser beam irradiation device and an operating method thereof for preventing optical damage to semiconductor elements. [Background technology]

[0002] Due to the rapid development of the electronics industry and user demands, electronic devices are becoming smaller, more highly integrated, and larger in area, and as a result, the size of semiconductor elements included in electronic devices is approaching the nanometer-level microscopic range.

[0003] Semiconductor processing methods related to the present disclosure include dicing, a type of cutting process in which a large-area wafer is cut and separated into multiple chips, a grinding process in which the thickness of the wafer is reduced, and a grooving process in which grooves for forming conductive wiring are formed.

[0004] In relation to dicing, blade dicing is used, which is a method of cutting a substrate using a thin cutting blade made of fine diamond. However, in the process of cutting a substrate using a cutting blade, chipping occurs on the front and back surfaces of the substrate, which can reduce the performance of the separated chips.

[0005] Another dicing process is stealth dicing, which focuses a laser beam on a localized area to form internal cracks for cutting. However, because the laser beam used in stealth dicing has an extremely high peak power, the process of forming the internal cracks can also cause cracks on the semiconductor surface, resulting in a decrease in chip performance. Summary of the Invention [Problem 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 operating method thereof that can improve chip performance by oscillating the laser beam to reduce the accumulation of thermal energy due to laser focusing. [Means for solving the problem]

[0007] In order to achieve the above-mentioned object, a laser beam irradiation device for semiconductor processing according to one aspect of the technical idea of ​​the present disclosure may include a laser beam output unit that advances a laser beam in a processing direction to process a semiconductor and vibrates the laser beam to have a certain amplitude in a vibration direction different from the processing direction, and a focusing lens that images the laser spot that advances in the processing direction and vibrates in the vibration direction on the semiconductor.

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

[0009] In addition, the laser beam output unit may 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 cutting surface on the semiconductor in order to perform pre-processing for cutting the semiconductor with good processing quality.

[0010] Meanwhile, the laser beam output unit may further include a laser oscillator unit that oscillates and outputs a laser beam, and a vibrator unit that physically vibrates an optical element so as to vibrate the laser beam irradiated from the laser oscillator unit in the vibration direction.

[0011] Furthermore, the laser oscillator and the focusing lens are fixed without vibration, and the optical element can be vibrated in simple harmonic motion by the driving force of the motor of the vibrating section.

[0012] The optical element may include a horizontal mirror, and the motor may be at least one of an ultrasonic motor and a resonant motor.

[0013] The motor may also include an input unit that receives an operation command for semiconductor processing, and a control unit that controls the vibration unit based on the operation command to apply a sine wave input to the motor in a first mode and to apply a triangular wave or a square wave to the motor in a second mode.

[0014] The first mode may be a user mode selected by a user who assigns a priority to the oscillation speed of the laser beam, and the second mode may be a user mode selected by a user who assigns a priority to the oscillation amplitude of the laser beam.

[0015] Meanwhile, the optical element includes a pair of polygon mirrors each having a number of reflecting surfaces, and the pair of polygon mirrors can rotate in different directions.

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

[0017] The incident angle is substantially a right angle, and the laser beam output unit can vibrate the laser beam by an amplitude in the vibration direction corresponding to a distance determined by a line width of the semiconductor substrate. [Effects of the Invention]

[0018] According to an exemplary embodiment of the present disclosure, unlike stealth dicing, destruction and deformation of the semiconductor material can be prevented by dispersing thermal energy by oscillating the laser beam rather than accumulating it in a small localized area.

[0019] According to an exemplary embodiment of the present disclosure, the quality of the irradiated object and the mass-produced product using the same can be ensured through pre-processing using a leading laser, and mass-produced quality can be achieved through complete cutting using a trailing laser.

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

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

[0022] According to exemplary embodiments of the present disclosure, by adjusting the angle of incidence of the oscillating laser beam to an acute, right or obtuse angle, customized results can be obtained to meet the producer's needs. [Brief explanation of the drawings]

[0023] [Figure 1] 1 is a conceptual diagram illustrating a laser beam irradiation device according to an exemplary embodiment of the present disclosure. [Figure 2a] 1 is a diagram illustrating a processing method using a laser beam irradiation device 10 according to an exemplary embodiment of the present disclosure. [Figure 2b] 1 is a diagram illustrating a processing method using a laser beam irradiation device 10 according to an exemplary embodiment of the present disclosure. [Figure 3] This is to illustrate conventional blade dicing and stealth dicing. [Figure 4] 1 is a diagram illustrating a method for oscillating a laser beam according to an exemplary embodiment of the present disclosure. [Figure 5]1 is a diagram illustrating a vibration method, a focusing lens, and a processing method of a laser beam irradiation device according to an exemplary embodiment of the present disclosure. [Figure 6] 1 is a diagram illustrating mirror vibration among vibration methods according to an exemplary embodiment of the present disclosure. [Figure 7] 1 is a diagram illustrating polygon vibration, which is one of the vibration methods according to an exemplary embodiment of the present disclosure. [Figure 8] 10 is a diagram illustrating light source vibration among vibration methods according to an exemplary embodiment of the present disclosure. [Figure 9] 1 is a diagram illustrating a focusing lens according to an exemplary embodiment of the present disclosure. [Figure 10] 10 is a diagram illustrating a vibration direction and a machining direction determined by a machining method according to an exemplary embodiment of the present disclosure. [Figure 11] 1 is for illustrating the processing direction and incident angle according to an exemplary embodiment of the present disclosure. [Figure 12] 10 is an electron microscope image for explaining the quality of semiconductor processing results according to an exemplary embodiment of the present disclosure together with a comparative example. [Figure 13] 10 is an electron microscope image for explaining the quality of semiconductor processing results according to an exemplary embodiment of the present disclosure together with a comparative example. DETAILED DESCRIPTION OF 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 illustrating a laser beam irradiation device 10 according to an exemplary embodiment of the present disclosure.

[0026] 1, a laser beam irradiation device 10 may 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 may 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 irradiation target ST by outputting a laser beam.

[0028] The object to be irradiated ST may include a semiconductor substrate or wafer. For ease of explanation, the object to be irradiated ST may hereinafter be described as a semiconductor, semiconductor substrate, or semiconductor wafer. In this case, the substrate may be processed in various ways using the thermal energy of the laser beam. The various methods include a dicing process in which a large-area wafer is cut and separated into multiple chips, a grinding process in which the thickness of the wafer is reduced, and a grooving process in which grooves for forming conductive wiring are formed.

[0029] The irradiation object ST may include a semiconductor film (e.g., an oxide film). For example, the laser beam irradiation device 10 may anneal the semiconductor film.

[0030] Hereinafter, "processing" may refer to a process in which the laser beam of the laser beam irradiation device 10 causes physical deformation in the irradiated object ST, and the technical idea of ​​the present disclosure is not limited to the above-mentioned examples.

[0031] According to an exemplary embodiment of the present disclosure, the laser beam application device 10 can oscillate the laser beam to lower the accumulation of heat energy focused by the laser spot LS.

[0032] Specifically, the laser beam irradiating device 10 can advance the laser beam in the processing direction to process the irradiated object ST. At the same time, the laser beam irradiating device 10 can oscillate the laser beam to have a certain amplitude (processing amplitude) in a vibration direction different from the processing direction. As a result, before the irradiated object ST is deformed due to excessive accumulation of thermal energy in the first laser spot LS1, the second laser spot LS2 oscillates, thereby reducing the defect rate of the irradiated object ST.

[0033] Meanwhile, as will be described later with reference to Figure 3, the laser beam irradiating device 10 can oscillate the laser beam with a constant amplitude in the same vibration direction as the processing direction. By oscillating the laser beam in the same vibration direction as the processing direction, the laser beam irradiating device 10 can pump or remove ejected materials (e.g., dust, particles, debris) generated during the processing of the irradiated object ST out of the processing area based on the oscillating laser. This prevents a decrease in yield due to the ejected materials.

[0034] The input unit 100 can receive an operation command from a user. For example, the operation command can include an instruction for the user to determine the line width to be engraved into the irradiation object ST, and for another example, the operation command can include an instruction to control the speed at which the irradiation object ST is processed.

[0035] The input unit 100 allows a user to select one of a first mode and a second mode. The first mode may be a user mode in which priority is assigned to the oscillation speed of the laser beam, and the second mode may be a user mode in which priority is assigned to the oscillation amplitude of the laser beam. Processing methods in the first mode and the second mode will be described later together with the control unit 200.

[0036] Meanwhile, the input unit 100 may be implemented as a device (e.g., a keyboard) or software (input user interface) that can receive user operation commands and transmit them to the control unit 200. Alternatively, the input unit 100 may be an input interface of an operating system (O / S). Without being limited thereto, the input unit 100 may include various types of input means in the form 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 oscillator 310 may be any type of oscillator capable of processing the irradiation target ST, which may be a semiconductor device or semiconductor component, or may include components included therein. For example, the laser oscillator 310 may include a laser with an output ranging from several hundred watts to several hundred kilowatts. The oscillation signal SO may control the overall operation of the laser oscillator 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 about a vibration amplitude, a vibration speed, and an input waveform. For example, the vibration unit 320 can include a resonance motor. Hereinafter, the resonance motor may refer to a driving device in which a vibrator vibrates in resonance, and can have a higher vibration frequency than a galvo motor.

[0040] The control unit 200 may 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 may include the waveform of an electrical signal applied to drive a motor.

[0041] The control unit 200 may 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 may 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 may be further increased.

[0042] In addition, the control unit 200 can output a vibration signal SV to apply a triangular wave or a square 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 square wave 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 oscillate at a amplitude closer to the target vibration amplitude.

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

[0044] For example, the irradiated laser beam may be a single ray, or for another example, multiple laser beams may be output from the laser beam irradiation device 10. When multiple laser beams are output, the laser oscillation unit 310 may include multiple oscillation modules for outputting the multiple laser beams.

[0045] In the process of vibrating the laser beam, only a part of the components 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 vibrate in simple harmonic motion by the driving force of the motor of the vibration unit 320. Compared to the case where the laser oscillation unit 310 and the focusing lens 400 vibrate, the processing of the irradiated object ST can be performed more precisely and heat accumulation 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 connected directly or indirectly to the optical element 330. The optical element 330 outputs the laser beam output from the laser oscillation unit 310 to the focusing lens 400, and 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 may include a mirror. That is, the optical element 330 may reflect the laser beam output from the laser oscillator 310 and output it to the focusing lens 400. The vibrating unit 320 may 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, which is to prevent excessive accumulation of thermal energy applied to the irradiation target 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 object ST, which may be between 0 degrees and 90 degrees.

[0049] The focusing lens 400 may be an objective lens, a short focal length lens, or an F-theta lens. The focusing lens 400 may be selected from the objective lens, the short focal length lens, and the F-theta lens according to the processing method and the user's requirements, as will be described later.

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

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

[0052] 2a and 2b, the laser beam irradiation device 10 may 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 in FIG. 1. Meanwhile, the laser beam irradiation device 10 may include a first focusing lens 400a and a second focusing lens 400b, each of which may correspond to the focusing lens 400 described above in FIG. 1.

[0053] According to an exemplary embodiment of the present disclosure, the laser beam irradiation device 10 can output a first laser to the workpiece ST along the processing direction in one processing run, and 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 may output a second laser for cutting the irradiated object ST. For example, the second laser may form a cut surface on the irradiated object ST. The first laser beam output unit 300a may output a first laser for performing pre-processing to cut the irradiated object ST to mass-production quality. Here, mass-production quality refers to the target quality that the processing entity aims to achieve, and may include, for example, cross-sectional uniformity, cutting speed, cutting size, line width, etc. Furthermore, for example, if the irradiated object ST is a wafer, the first laser beam output unit 300a may output a first laser for the purpose of removing compounds 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 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 for processing by the first laser beam output unit 300a. In this sense, the first laser can be referred to as a leading laser, and the second laser can be referred to as a trailing laser.

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

[0057] According to an exemplary embodiment of the present disclosure, the first laser beam output unit 300a may have a higher intensity but a lower average power than the second laser beam output unit 300b. Experiments have shown that if the average power of the leading laser output from 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 processing quality when the second laser beam output unit 300b actually performs processing (e.g., cutting). Therefore, the first laser (i.e., the leading laser) may have a higher intensity but a lower average power than the second laser (i.e., the trailing laser).

[0058] 2a, the first laser beam output unit 300a may output a first laser beam to the target object ST in a vertical direction of the target object ST, and the second laser beam output unit 300b may output a second laser beam at a first angle θa relative to the processing direction, where the first angle θa may be greater than 90 degrees and less than 180 degrees.

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

[0060] Referring to FIG. 2b, the first laser beam output unit 300a may output a first laser beam at a second angle θb with respect to the processing direction. Here, the second angle θb may be greater than 0 degrees and less than 90 degrees. In the case of a sensitive and fragile target ST, outputting the first laser beam at an acute incident angle can improve the quality of processing the target ST by the second laser beam output unit 300b. Furthermore, compared to a first laser beam having a vertical incident angle, a first laser beam having an acute incident angle can be output to the target ST at a higher output power and still achieve target processing quality. Therefore, surface removal and depth processing can be more easily performed at once with more energy.

[0061] 2a, the first laser beam output unit 300a may output a first laser beam that vibrates in an oscillating motion, i.e., vibrates along the processing direction. For example, when vibrating the first laser, cutting can be performed more effectively and quickly by using both the first and second lasers when processing a thick target object ST. However, without being limited thereto, the first laser beam output unit 300a may output a first laser beam that does not vibrate while having the second angle θb.

[0062] Referring to FIGS. 2a and 2b, full cutting of an irradiated object ST (e.g., a semiconductor wafer) can be achieved through the sequential cutting operation of a leading laser (i.e., a first laser) and a trailing laser (i.e., a second laser). In other words, when attempting to fully cut an irradiated object ST using a single laser in the past, excessive laser beam output prevented mass production quality from being achieved (e.g., FIGS. 12(a) and 13(a)). However, according to an exemplary embodiment of the present disclosure, the quality of the irradiated object ST and the mass production results using the irradiated object ST can be ensured through pre-processing using the leading laser, and full cutting using the trailing laser can achieve mass production quality. Furthermore, by using the leading and trailing lasers, 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] Figure 3 is used to explain conventional blade dicing and stealth dicing.

[0064] 3(a), the blade dicing device rapidly rotates a thin cutting blade made of fine diamond, that is, the blade dicing device cuts an object using a saw blade formed on the cutting blade.

[0065] During this process, the cutting blade may peel off the cutting surface of the front or back surface of the substrate where the blade is positioned while cutting the target object (e.g., substrate). Also, chipping may occur in the substrate during the process of peeling off the target object. This can be a major factor in reducing the performance of the separated chips after dicing is completed.

[0066] However, in the laser beam irradiation method, a strong laser beam is irradiated to a localized area, so the above-mentioned performance degradation factors do not occur.

[0067] On the other hand, referring to FIG. 3(b), a stealth dicing device can focus a laser beam on a localized area of ​​a target object to form internal cracks for cutting. The target object can be separated along the cracks formed in a specific pattern. During the separation process, the cut surface of the area adjacent to the cracks may be irregular. Furthermore, because the stealth dicing laser beam has an extremely high peak power, unwanted cracks may be further generated on the semiconductor surface, resulting in a decrease in chip performance.

[0068] However, according to the exemplary embodiment of the present disclosure, the irradiated object ST is entirely cut using a laser beam, eliminating the need for a separate peeling process compared to stealth dicing, thereby eliminating the cause of performance degradation. Furthermore, even with a high peak power like stealth dicing, the time the laser stays in a specific area can be significantly reduced by vibration compared to stealth dicing, preventing deformation of the irradiated object ST due to the accumulation of thermal energy.

[0069] 4 is a diagram illustrating a method for oscillating a laser beam according to an exemplary embodiment of the present disclosure, which will be described below in chronological order in the order of (a) to (c) in FIG.

[0070] 4(a) to 4(c), the laser beam irradiation device 10 oscillates the laser beam LB3, thereby outputting the laser beam LB3 at different positions on the focusing lens 400. For convenience of explanation, different reference numerals are given to the laser beams LB31 to LB33 in the first, second, and third phases, but the laser beams LB31 to LB33 may be one laser beam output from the same laser oscillator 310. However, the present invention is not limited thereto, and the laser beams LB31 to LB33 may be laser beams generated by different oscillators.

[0071] In chronological order, the laser beam irradiation device 10 first outputs a laser beam LB31 to the edge region of the focusing lens 400. Then, due to vibration, the laser beam irradiation device 10 outputs a laser beam LB32 to the central region of the focusing lens 400. Then, due to vibration, the laser beam irradiation device 10 outputs a laser beam LB33 to the edge region opposite the edge region at the first stage.

[0072] The laser beam irradiation device 10 can form laser spots LS on different regions a1 to a3 of the irradiation object ST. The laser beam irradiation device 10 can process the regions a1 to a3 that are not far apart in the x-axis direction but are separated by a vibration distance (processing width, line width) in the y-axis direction. Here, the vibration distance can correspond to the line width of the conductor. In other words, 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 oscillate the laser beam LB3 so that the laser spot LS remains in a localized area (e.g., a1) only for a time period during which no material deformation occurs according to a preset quality standard.

[0074] For example, the control unit 200 may transmit the vibration signal SV so that the vibrating unit 320 has at least one vibration speed greater than 0 and less than or equal to 20 kHz. In this case, if the control unit 200 outputs the vibration signal SV having a vibration speed equal to or greater than 1 kHz, the vibrating unit 320 may be embodied as one of an ultrasonic motor and a resonant motor.

[0075] As another example, the control unit 200 may transmit the vibration signal SV so that the vibration unit 320 has at least one vibration speed in the range of more than 0 to 10 MHz.

[0076] According to one embodiment, the laser beam irradiation device 10 receives input through the input unit 100 that the irradiated object ST is a wafer made of a first material, and the control unit 200 transmits a vibration signal SV including a first frequency, thereby controlling the laser spot LS to remain in a local area (e.g., a1) for a time corresponding to the first frequency.

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

[0078] According to one embodiment of the present disclosure, the laser beam irradiation device 10 can form a cut surface having a width equal to the oscillation distance in the y-axis direction by the oscillating laser beam LB4 passing through the focusing lens 400. In other words, 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 equal 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 yet another embodiment of the present disclosure, the laser beam irradiation device 10 can perform the grinding process by oscillating the laser beam LB4 largely in the y-axis direction.

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

[0082] The focusing lens 400 will be described with reference to FIG. 9, and the cases of an objective lens, a short focal length lens, and an F-theta lens will be described.

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

[0084] 6, the vibration unit 320 may include a motor 321, which may be at least one of an ultrasonic motor and a resonant motor. Also, the optical element 330 may include a horizontal mirror 331.

[0085] According to an exemplary embodiment of the present disclosure, the horizontal mirror 331 is mechanically coupled to the motor 321, and the driving force of the motor 321 is transmitted to the mirror, causing the horizontal mirror 331 to vibrate in simple harmonic motion. In this case, the frequency of the simple harmonic motion may 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 may vibrate in a direction parallel to the focusing lens 400. Accordingly, the laser beam may vibrate back and forth between points that are symmetrical with respect to the origin, with the center point of the focusing lens 400 as the reference point.

[0087] According to an exemplary embodiment of the present disclosure, the optical element 330 may vibrate in a direction in which the laser output from the laser oscillation unit 310 is incident on the optical element 330. In this case, the optical element 330 may 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 may be a vibration motor such as an ultrasonic motor or a resonant motor. The vibration motor may generate a driving force by generating a high frequency vibration inside the motor 321. The high frequency driving force may be transmitted to the horizontal mirror 331, which is structurally directly or indirectly coupled to the motor 321, through a transmission part of the motor 321.

[0089] Preferably, the motor 321 generates a vibration frequency equal to or greater than 1 kHz and equal to or less than 20 kHz. That is, at least one of the ultrasonic motor and the resonant motor vibrates the laser beam at a frequency equal to or greater than 1 kHz and equal to or less than 20 kHz, thereby increasing process yield by allowing the vibrating laser beam to pump out debris (e.g., dust, particles, and debris) generated during semiconductor processing. While commonly used linear actuator motors cannot achieve the effects of the exemplary embodiments of the present disclosure due to their low vibration frequencies of less than 1 kHz, it has been confirmed through numerous experiments that a laser beam at a frequency equal to or greater than 1 kHz and equal to or less than 20 kHz can significantly reduce thermal deformation of the irradiated object ST while pumping out debris.

[0090] Referring to (a) of Figure 6, in a first phase, the horizontal mirror 331 can be located at point b1. Referring to (b) of Figure 6, in a second phase, the horizontal mirror 331 can be located at point b3 via point b2 due to the driving force (vibration) of the motor 321. Thereafter, the horizontal mirror 331 can move back and forth from point b3 to point b1 due to the driving force (vibration) of the motor 321.

[0091] That is, the laser beam irradiation device 10 according to an exemplary embodiment of the present disclosure can output a laser beam vibrating in a 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 on this.

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

[0093] Referring to FIG. 7, the optical element 330 includes a pair of polygonal mirrors 332, which may include a first polygonal mirror 332a and a second polygonal mirror 332b having multiple reflective surfaces.

[0094] According to an exemplary embodiment of the present disclosure, the laser oscillator 310 may include a plurality of oscillator modules. For example, the laser oscillator 310 may output a plurality of laser beams including a first laser beam i_a and a second laser beam i_b. The laser oscillator 310 may output the first laser beam i_a to the first polygon mirror 332a and 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 vibrating unit 320 may be implemented as a rotary motor, which may rotate the first polygon mirror 332a and the second polygon mirror 332b in different directions. As another example, the vibrating unit 320 may be implemented as a vibration motor, which may output a driving force (vibration) to the polygon mirrors such that the first polygon mirror 332a and the second polygon mirror 332b vibrate in opposite phases.

[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 and o_b may be output to the irradiation target ST, and the reflected output laser beams o_a and o_b may vibrate in different directions from each other.

[0097] Furthermore, the reflected output laser beams o_a and o_b can each oscillate in a single direction. For example, the first output laser beam o_a can oscillate from 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, and so on, on the irradiation object ST. The second output laser beam o_b can oscillate from 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, and so on, in that order. That is, after 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 object ST by outputting output laser beams o_a and o_b that vibrate in simple harmonic motion in different directions to the object ST. At this time, the direction of the simple harmonic motion may be different from the direction in which the processing of the object ST progresses.

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

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

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

[0102] According to an exemplary embodiment of the present disclosure, the laser oscillator 310 can be directly or indirectly mechanically coupled to the vibrating unit 320 to transmit a driving force (vibration). Unlike Fig. 5, the fixed horizontal mirror 333 and the focusing lens 400 can be fixed without vibration, and the laser oscillator 310 can be vibrated by the vibrating unit 320. For example, the laser oscillator 310 can oscillate in a simple harmonic motion by starting from point d1, moving to point d3, and then going back and forth from point d3 to point d1.

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

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

[0105] Referring to Fig. 9(a), the focusing lens 400 can be realized as an f-theta lens 401, and Fig. 9(b) illustrates an achromatic lens 402. Unlike the achromatic lens 402, the f-theta lens 401 may not experience the upper surface curvature phenomenon.

[0106] The laser beam irradiation device 10 according to the exemplary embodiment of the present disclosure can be used for nano-scale semiconductor processing. When a curvature phenomenon occurs, such as with an achromatic lens 402, it can be difficult to achieve the effects of the present invention in accordance with the technical concept of the present disclosure, since the oscillation amplitude cannot be precisely adjusted. Accordingly, the laser beam irradiation device 10 can precisely adjust the oscillation amplitude using an f-theta lens 401.

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

[0108] Meanwhile, the focusing lens 400 according to the exemplary embodiment of the present disclosure may include an objective lens. In this case, the objective lens may have a magnification of 5x or more and 100x or less. The objective lens is optimized to form a finer laser spot LS than the above-described f-theta lens 401. Experiments have shown that when the objective lens among the above-described lenses is embodied as the focusing lens 400, the diameter of the laser spot LS can be formed to be the smallest and most clear. This will be described in conjunction with FIG. 9.

[0109] FIG. 10 is a diagram illustrating the vibration direction and the machining direction determined by the machining method according to the 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 lateral direction.

[0111] Accordingly, when the irradiation object ST is embodied 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 (vertical direction).

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

[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 Figures 11(a), (b), and (c), respectively, the laser beam irradiation device 10 can perform forward machining, perpendicular (vertical) machining, and reverse machining depending on the angle of incidence. In the forward machining mode, the laser beam irradiation device 10 can output a laser beam to the workpiece ST at an acute angle θ1 relative to the machining direction. In the perpendicular (vertical) machining mode, the laser beam irradiation device 10 can output a laser beam to the workpiece ST at a perpendicular angle θ2 relative to the machining direction. In the reverse machining mode, the laser beam irradiation device 10 can output a laser beam to the workpiece ST at an obtuse angle θ3 relative to the machining direction. The uses and benefits of each machining method have been described above, so they will not be discussed here.

[0116] According to an exemplary embodiment of the present disclosure, the laser beam irradiation device 10 may have different penetration depths into the irradiated object ST depending on the incident angle of the laser beam. For example, when etching only a first depth, the laser beam irradiation device 10 may perform orthogonal processing, and when etching only a second depth shallower than the first depth, the laser beam irradiation device 10 may perform forward processing or reverse processing.

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

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

[0119] According to the comparative example, it can be seen that non-homogeneous regions occur on both the surface and cross section, resulting in a deterioration in processing quality.

[0120] However, according to the exemplary embodiment of the present disclosure, a smooth cross section can be confirmed, and the surface does not experience cracking due to the laser, confirming excellent processing quality.

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

[0122] According to the comparative example, it can be seen that by irradiating a strong laser beam in the processing direction without vibration, the irradiated object is damaged even in areas other than the target area due to the strong heat of the laser.

[0123] However, according to an exemplary embodiment of the present disclosure, a laser beam having an appropriate intensity is irradiated in the processing direction while being vibrated in the vibration direction, so that no damage caused by the laser can be found in areas other than the target area.

[0124] As described above, exemplary embodiments have been disclosed in the drawings and specification. Although specific terms have been used to describe the embodiments in this specification, these terms are used solely for the purpose of describing the technical ideas of the present disclosure and are not intended to limit the meaning or the scope of the present disclosure as described in the claims. Therefore, a person skilled in the art will understand that various modifications and equivalent embodiments are possible. Therefore, the true technical scope of protection of the present disclosure should be determined by the technical ideas of the appended claims.

Claims

1. In a laser beam irradiation device for semiconductor processing, a laser beam output unit that advances a laser beam in a processing direction to process a semiconductor and vibrates the laser beam to have a constant amplitude in a vibration direction different from the processing direction; and a focusing lens that focuses a laser spot, which advances in the processing direction and vibrates in the vibration direction, on the semiconductor; Including, The laser beam output unit a laser oscillator 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; Including, the laser oscillator and the focusing lens are fixed without vibration, and the optical element vibrates in simple harmonic motion due to the driving force of the motor of the vibration unit; The laser beam irradiation device an input unit for receiving operation instructions for semiconductor processing; and a control unit that controls the vibration unit to apply a sine wave input to the motor in a first mode and a triangular wave or a square wave to the motor in a second mode based on the operation command. Laser beam irradiation device.

2. the optical element includes a horizontal mirror; The motor is at least one of an ultrasonic motor and a resonant motor.

2. The laser beam irradiation device according to claim 1.

3. the first mode is a user mode selected by a user who assigns a priority to the oscillation speed of the laser beam; The second mode is a user mode selected by a user who assigns a priority to the oscillation width of the laser beam.

3. The laser beam irradiation device according to claim 1 or 2.

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