Laser processing equipment

Abstract

The laser processing apparatus includes: a stage configured to support a substrate as a processing target and a reflective structure for measurement; a laser output section configured to output a laser beam; a focusing lens configured to focus the laser beam on the substrate in a processing mode for processing the substrate, and to focus the laser beam on the reflective structure in a measurement mode for measuring the laser beam; an aberration measurement optical system configured to receive reflected light of the laser beam from the reflection structure through the focus lens and measure an aberration of the laser beam; and an aberration corrector disposed on an optical path of the laser beam incident from the laser output portion to the focus lens, and configured to correct aberration of the laser beam based on measured aberration information of the laser beam.

Description

[0001] This application claims priority to Korean Patent Application No. 10-2024-0130840, filed on September 26, 2024, with the Korean Intellectual Property Office (KIPO), the entire contents of which are incorporated herein by reference. Technical Field

[0002] At least some example embodiments relate to laser processing apparatus and / or laser processing methods. For example, some example embodiments relate to laser processing apparatus configured to perform laser processing processes by irradiating a laser onto the surface of a substrate, and laser processing methods using the same laser processing apparatus. Background Technology

[0003] Laser processing equipment can process objects (such as wafers) by focusing a pulsed laser beam using an optical lens. For example, the equipment can perform laser processing techniques on the object (such as cutting, grooving, scribing, or drilling). For instance, when performing stealth cutting using a focusing lens with a high numerical aperture (NA), the optical system (such as the focusing lens) can introduce aberrations, thus degrading the processing quality. Therefore, it is advantageous to measure the aberrations of the laser beam passing through the focusing lens and to correct these aberrations based on the measured aberrations. Summary of the Invention

[0004] At least some example embodiments relate to a laser processing apparatus capable of measuring (and / or correcting) the aberrations of a laser beam passing through a focusing lens.

[0005] At least some of the example embodiments relate to a laser processing method using a laser processing apparatus according to the example embodiments.

[0006] According to some example embodiments, a laser processing apparatus may include: a stage configured to support a substrate as a processing target and a reflective structure for measurement; a laser output unit configured to output a laser beam; a focusing lens configured to focus the laser beam onto the substrate in a processing mode for processing the substrate and onto the reflective structure in a measurement mode for measuring the laser beam; an aberration measurement optical system configured to receive light reflected from the reflective structure of the laser beam through the focusing lens and measure the aberrations of the laser beam; and an aberration corrector configured to correct the aberrations of the laser beam based on the measured aberration information of the laser beam along the optical path of the laser beam from the laser output unit to the focusing lens.

[0007] According to some example embodiments, a laser processing apparatus may include: a stage configured to support a substrate as a processing target and a reflective structure for measurement; a laser output unit configured to output a first laser beam having a first polarization direction and a second laser beam having a second polarization direction perpendicular to the first polarization direction; a focusing lens configured to focus the first and second laser beams onto the substrate in a processing mode for processing the substrate, and to focus the first and second laser beams onto the reflective structure respectively in a measurement mode for measuring the first and second laser beams; and an aberration measurement optical system configured to... The system receives light reflected by a reflective structure from each of a first laser beam and a second laser beam through a focusing lens, and measures the aberrations of each of the first laser beam and the second laser beam; a first aberration corrector is disposed in the optical path of the first laser beam from the laser output section to the focusing lens, and the first aberration corrector is configured to correct the aberrations of the first laser beam based on the measured aberration information of the measured first laser beam; and a second aberration corrector is disposed in the optical path of the second laser beam from the laser output section to the focusing lens, and the second aberration corrector is configured to correct the aberrations of the second laser beam based on the measured aberration information of the second laser beam.

[0008] According to some example embodiments, a laser processing apparatus may include: a stage configured to support a reflective structure; a laser output unit configured to output a laser beam; a focusing lens configured to focus the laser beam onto the reflective structure; an aberration measurement optical system configured to receive light reflected from the reflective structure of the laser beam through the focusing lens to measure the aberrations of the laser beam; and an aberration corrector disposed in the optical path of the laser beam from the laser output unit to the focusing lens, the aberration corrector being configured to correct the aberrations of the laser beam based on measured aberration information of the laser beam, and the aberration measurement optical system including: a polarization beam splitter configured to transmit a laser beam having a first polarization direction and reflect a laser beam having a second polarization direction perpendicular to the first polarization direction; at least one waveplate in the optical path between the polarization beam splitter and the reflective structure, the at least one waveplate being configured to change the polarization direction of the laser beam transmitted through the polarization beam splitter; and an aberration sensor configured to receive reflected light from the laser beam reflected by the polarization beam splitter, the aberration sensor being configured to measure the aberrations of the laser beam, wherein the at least one waveplate is in the optical path or outside the optical path.

[0009] According to some example embodiments, a laser processing apparatus may include: a laser output unit configured to output a laser beam; a focusing lens configured to focus the laser beam onto a substrate in a processing mode and onto a reflective structure in a measurement mode; an aberration measurement optical system configured to receive reflected light from the laser beam from the reflective structure via the focusing lens to measure the aberrations of the laser beam; and an aberration corrector for correcting the aberrations of the laser beam based on aberration information measured from the laser beam.

[0010] According to some example embodiments, a laser processing method may include: placing a reflective structure on a stage; emitting a laser beam from a laser output section; focusing the laser beam onto the reflective structure through a focusing lens; receiving light reflected from the reflected structure of the laser beam through the focusing lens; correcting aberrations of the laser beam based on aberration information of the reflected light received through the focusing lens; placing a substrate on the stage; focusing the corrected laser beam onto the substrate, the corrected laser beam being focused through the focusing lens; and scanning the corrected laser beam along one or more cutting lines of the substrate.

[0011] According to some example embodiments, the laser processing method may further include: obtaining aberration information by measuring the aberrations of the laser beam using an aberration optical system during the measurement mode of the laser processing equipment. The aberration optical system includes an aberration optical path forming section and an aberration sensor.

[0012] According to some example embodiments, the laser processing method may further include: guiding reflected light received through a focusing lens to an aberration sensor, the guiding using an optical path forming unit.

[0013] According to some example embodiments, the laser processing method may further include: correcting the aberrations of the laser beam by using an aberration corrector, the correction being based on aberration information measured by an aberration measuring optical system.

[0014] According to some example embodiments, the laser processing method may include: measuring aberration information of a laser beam using an aberration measurement optical system, the aberration measurement optical system including a polarization beam splitter, at least one waveplate, and an aberration sensor, the polarization beam splitter being configured to transmit a laser beam having a first polarization direction and reflect a laser beam having a second polarization direction, the at least one waveplate being in the optical path between the polarization beam splitter and a reflecting structure and being configured to change the polarization direction of the laser beam transmitted through the polarization beam splitter, and the aberration sensor being configured to receive light of the laser beam reflected by the polarization beam splitter and to measure the aberrations of the laser beam.

[0015] According to some example embodiments, a laser processing method may include: placing a reflective structure on a stage; emitting a first laser beam and a second laser beam from a laser output section, the first laser beam having a first polarization direction and the second laser beam having a second polarization direction perpendicular to the first polarization direction; focusing the first laser beam and the second laser beam onto the reflective structure through a focusing lens; receiving light reflected from the reflective structure from each of the first laser beam and the second laser beam through the focusing lens; correcting aberrations of the first laser beam and the second laser beam based on aberration information of the reflected light received through the focusing lens; placing a substrate on the stage; focusing the corrected first laser beam and the second laser beam onto the substrate, the corrected first laser beam and the second laser beam being focused through the focusing lens; and scanning the corrected first laser beam and the second laser beam along one or more cutting lines of the substrate.

[0016] An aberration measurement optical system can measure the aberrations of a laser beam that has passed through a focusing lens in measurement mode, while in processing mode it does not affect or substantially affect the propagation of the laser beam. An aberration corrector can adjust the phase of the laser beam based on the measured aberration information to correct the aberrations, thereby improving the processing quality of the laser beam accordingly. Attached Figure Description

[0017] Various exemplary embodiments will become clearer from the following detailed description taken in conjunction with the accompanying drawings. Figures 1 to 16 This relates to various non-limiting example embodiments as described herein.

[0018] Figure 1 This is a perspective view showing a laser processing apparatus according to an example embodiment.

[0019] Figure 2 It is shown Figure 1 A block diagram of a laser irradiator.

[0020] Figure 3 It is shown in Figure 1 A block diagram of the measurement mode of the laser beam performed in the laser processing equipment.

[0021] Figure 4 It is shown in Figure 1 A block diagram of the processing modes performed in laser processing equipment.

[0022] Figure 5A It is shown Figure 1 A cross-sectional view of a portion of the aberration sensor in a laser processing device.

[0023] Figure 5B It is shown in Figure 5A A planar image of spots detected in the pixels of an image sensor.

[0024] Figure 6This is a block diagram illustrating a laser processing apparatus according to an example embodiment.

[0025] Figure 7 It is shown in Figure 6 A block diagram of the measurement mode of the first laser beam executed in a laser processing device.

[0026] Figure 8 It is shown in Figure 6 A block diagram of the measurement mode of the second laser beam executed in the laser processing equipment.

[0027] Figure 9 It is shown in Figure 6 A block diagram of the processing modes performed in laser processing equipment.

[0028] Figure 10 This is a block diagram illustrating a laser processing apparatus according to an example embodiment.

[0029] Figure 11 It is shown in Figure 10 A block diagram of the measurement mode of the first laser beam executed in a laser processing device.

[0030] Figure 12 It is shown in Figure 10 A block diagram of the measurement mode of the second laser beam executed in the laser processing equipment.

[0031] Figure 13 It is shown in Figure 10 A block diagram of the processing modes performed in laser processing equipment.

[0032] Figure 14 This is a flowchart illustrating a laser processing method according to an example embodiment.

[0033] Figure 15 It is a cross-sectional view showing a wafer irradiated by both a first laser beam and a second laser beam.

[0034] Figure 16 This is a plan view showing the scan lines on the wafer. Figure 15 The first and second laser beams scan along the scanning line. Detailed Implementation

[0035] In the following text, various exemplary embodiments will be explained in detail with reference to the accompanying drawings.

[0036] Figure 1 This is a perspective view showing a laser processing apparatus according to an example embodiment. Figure 2 It is shown Figure 1 A block diagram of a laser irradiator. Figure 3 It is shown in Figure 1 A block diagram of the measurement mode of the laser beam performed in the laser processing equipment. Figure 4 It is shown in Figure 1 A block diagram of the processing modes performed in laser processing equipment. Figure 5A It is shown Figure 1 A cross-sectional view of a portion of the aberration sensor in a laser processing device, and Figure 5B It is shown in Figure 5A A planar image of spots detected in the pixels of an image sensor.

[0037] Reference Figures 1 to 5B The laser processing equipment 10 may include a stage 20 and a laser irradiator 30. The laser processing equipment 10 may also include a controller 40 connected to the stage 20 and the laser irradiator 30 to control their operation.

[0038] In some example embodiments, the laser processing apparatus 10 may irradiate a substrate W (such as a wafer) with a laser beam L1 to apply locally high-density energy to a focal point P, thereby forming a stealth dicing layer as a modified region. The laser processing apparatus 10 may scan the laser beam L1 along a scan line (or dicing line or dicing region) S on the substrate W. Therefore, a laser-damaged layer as a modified region may be formed within the substrate W along the scan line. The laser-damaged layer formed along the scan line (e.g., a scribe line region) may be a dicing initiation point region.

[0039] The laser processing apparatus 10 may also include a drive unit configured to move the laser beam L1 relative to the substrate W. The drive unit may include a stage driver 22 configured to move the stage 20 in the X-axis, Y-axis and Z-axis directions.

[0040] For example, stage 20 may be a worktable (or operating table) movable in at least one direction and supporting base W. Stage 20 may be mounted on stage driver 22 to be movable in at least the X and Y directions. Stage driver 22 includes a stage drive mechanism for moving stage 20, and stage driver 22 may move stage 20 in the X and Y directions according to control signals from controller 40. The moving speed of stage 20 may be adjustable.

[0041] The drive unit may also include a laser head driver configured to move the laser irradiator 30 in the X, Y, and Z directions. For example, the laser head driver can move the optical system of the laser irradiator 30 in the X, Y, and Z directions. For example, the laser head driver can move the laser irradiator 30 in the Z direction, and the stage driver 22 can rotate the stage 20 to move the wafer W in the X and Y directions and rotate it about the center of the wafer W.

[0042] like Figure 2 , Figure 3 and Figure 4As shown, the laser illuminator 30 may include: a laser output unit 300 for outputting a laser beam L1; a focusing lens 350 for focusing the laser beam L1 onto a substrate W; and an aberration measurement optical system 340 for measuring the aberrations of the laser beam L1 passing through the focusing lens 350. The laser illuminator 30 may also include an aberration corrector 332 for correcting the aberrations of the laser beam L1 based on the aberration information of the measured laser beam.

[0043] The stage 20 can support the substrate W, which serves as the processing target, and the reflective structure BW, used for measuring the laser beam. The stage 20 can move the substrate W and the reflective structure BW based on the operating mode.

[0044] For example, stage 20 can position substrate W at the focal point of focusing lens 350 in a processing mode for processing substrate W. In processing mode, stage driver 22 can move stage 20 according to control signal from controller 40, so that substrate W is positioned at the focal point of focusing lens 350. Stage 20 can also position reflective structure BW at the focal point of focusing lens 130 in a measurement mode for laser beam L1. In measurement mode, stage driver 22 can move stage 20 according to control signal from controller 40, so that reflective structure BW is positioned at the focal point of focusing lens 350.

[0045] For example, the substrate W may include a silicon wafer (Si wafer), a silicon carbide wafer (SiC wafer), a gallium arsenide wafer (GaAs wafer), or a single-crystal silicon wafer (Si single-crystal wafer). The substrate W may have multiple die regions D arranged in a matrix shape and separated by dicing regions S. Circuit elements may be formed in the active surface of the substrate W.

[0046] The reflective structure BW may include a mirror or a reflector. The reflective structure BW may include the same material as the substrate W. For example, the reflective structure BW may include a substrate (such as a silicon wafer (Si wafer)). The reflective structure BW may be a wafer before processing (e.g., a bare wafer). The thickness of the reflective structure BW may be determined based on the type of laser processing equipment 10 and the thickness T1 of the substrate W as the processing target. The reflective structure BW may have a thickness of 40% to 60% of the thickness T1 of the substrate W. When the thickness of the substrate W is 700 μm, the reflective structure BW may include a thickness T2 of approximately 350 μm. As described below, the laser beam may be focused on the upper surface of the reflective structure BW disposed on the stage 20, and the laser beam may pass through the reflective structure BW, be reflected by the reflector, and then pass back through the reflective structure. Therefore, the transmission and reverse transmission of the reflective structure BW may correspond to the unidirectional transmission of the substrate W.

[0047] An anti-reflective layer (ARL) can be applied to the upper surface of the reflective structure BW. The ARL reduces, limits, or prevents surface reflection of the reflective structure BW, allowing most of the laser beam incident on the upper surface of the reflective structure BW to pass through the reflective structure BW and then pass through again to be emitted as reflected light through the upper surface of the reflective structure BW.

[0048] The laser output unit 300 may include a laser source 310 for generating a laser beam L0. For example, the laser source 310, as a single light source, may emit the laser beam L0. The laser beam L0 may have a wavelength band that is transparent to the substrate W, which is the object to be processed. This wavelength band may be in the wavelength range of 1080 nm to 1100 nm. The laser source 310 may emit a pulsed laser beam. However, the inventive concept is not limited to this, and a continuous wave laser beam may be emitted depending on the type of processing operation. The laser beam L0 may be an ultrashort pulse laser beam with a pulse width of 1 μs or less (e.g., picosecond or femtosecond order).

[0049] The laser output unit 300 may further include a power controller 326 for adjusting the waveform and power of the laser beam L0, and a beam expander 327 for expanding the diameter of the laser beam. The laser output unit 300 may also include a laser measurement unit for measuring the waveform, power, etc., of the output laser beam. The laser measurement unit can measure the pulse width, rise time, pulse peak value, etc., of the laser beam. The laser measurement unit may include at least one photodiode (PD) sensor.

[0050] The power controller 326 adjusts the waveform and power of the laser beam so that the measured values ​​by the laser output unit meet a predetermined (or optionally, desired) reference. The beam expander 327 expands the diameter of the collimated input beam and outputs a collimated output beam with a larger diameter. The beam expander 327 can be constructed from a combination of multiple lenses. The beam expander 327 can adjust the beam size while maintaining the same output value.

[0051] In some example embodiments, an aberration corrector 332 may be disposed in the optical path of the laser beam L1 incident from the laser output section 300 to the focusing lens 350, and may correct aberrations of the laser beam. The aberration corrector 332 may correct aberrations of the laser beam L1 based on aberration information of the laser beam measured by the aberration measurement optical system 340. The aberration corrector 332 may include a spatial light modulator (SLM). The spatial light modulator may be disposed in the optical path of the laser beam L1, and may modulate the phase of the laser beam L1. The spatial light modulator may be an optical device capable of spatially modulating the beam. The spatial light modulator may include optical elements in the form of a two-dimensional array.

[0052] As described below, controller 40 can calculate whether to correct aberrations and the correction value for eliminating aberrations based on aberration information acquired from aberration measurement optical system 340, and output a control signal reflecting the calculated correction value to aberration corrector 332. Each pixel of the spatial light modulator can change its optical properties through an electrical signal from controller 40, thereby changing the phase of the laser beam incident on each pixel. The spatial light modulator can spatially control the phase of the laser beam.

[0053] The focusing lens 350 can focus the laser beam L1, which has passed through the aberration corrector 332, onto the substrate W or the reflecting structure BW on the stage 20. The focusing lens 345 can be disposed in the optical path of the laser beam and can include a single-lens optical system having a numerical aperture NA of at least 0.6. For example, the focusing lens 350 can include a single-lens optical system in which multiple lenses are arranged sequentially.

[0054] In some example embodiments, the aberration measurement optical system 340 can measure the aberration of a laser beam by receiving the reflected light RL1 from the laser beam of the reflecting structure BW via a focusing lens 350. The aberration measurement optical system 340 may include an optical path forming unit 341 and an aberration sensor 348. The optical path forming unit 341 can guide the reflected light RL1 from the laser beam passing through the focusing lens 350 from the reflecting structure BW to the aberration sensor 348. The optical path forming unit 341 can transmit the laser beam L1 provided from the laser output unit 300 to the focusing lens 350, and can transmit the reflected light RL1 of the laser beam reflected by the reflecting structure BW after passing through the focusing lens 350 to the aberration sensor 348. The optical path forming unit 341 may include a polarizing beam splitter 342 and a wavelength plate (or wavelength disk) 346. The optical path forming unit 341 may also include optical elements (such as at least one mirror, at least one lens, etc.).

[0055] The polarization beam splitter 342 can transmit a laser beam having a first polarization direction and reflect a laser beam having a second polarization direction perpendicular to the first polarization direction. A waveplate 346 can be disposed in the optical path between the polarization beam splitter 342 and the reflecting structure BW to change the polarization direction of the laser beam that has passed through the polarization beam splitter 342. The waveplate 346 may include a quarter-wave plate. The polarization beam splitter 342 and the waveplate 346 can be configured to be movable according to the operating mode of the laser processing apparatus 10. The laser processing apparatus 10 may include a moving mechanism for moving the polarization beam splitter 342 and the waveplate 346. The moving mechanism can move the polarization beam splitter 342 and the waveplate 346 based on control signals from the controller 40.

[0056] like Figure 3As shown, in the measurement mode for measuring the aberrations of the laser beam L1, the polarizing beam splitter 342 and the waveplate 346 can be positioned in the optical path between the aberration corrector 332 and the focusing lens 350. The polarizing beam splitter 342 and the waveplate 346 can be moved in a first direction (X direction) based on the operating mode. The focusing lens 350 can focus the laser beam L1, which has passed through the polarizing beam splitter 342, onto the reflecting structure BW supported on the stage 20. For example, the polarizing beam splitter 342, the waveplate 346, and the focusing lens 350 can be located on the same axis.

[0057] For example, the laser output unit 300 can output a laser beam L1 with a first polarization direction (e.g., P-polarization), and the polarization beam splitter 342 can transmit the laser beam L1 with the first polarization direction. The laser beam L1 with the first polarization direction can pass through the waveplate 346 and then be incident on the reflective structure BW, and the reflected light RL1 of the laser beam can pass through the waveplate 346 and be incident again on the polarization beam splitter 342. The waveplate 346 can delay the phase of the light passing through it, for example, by 1 / 4 wavelength. As the laser beam passes through the waveplate 346 twice, the reflected light RL1 of the laser beam that is incident again on the polarization beam splitter 342 can be changed to have a second polarization direction (i.e., S-polarization).

[0058] The polarization beam splitter 342 can reflect a laser beam with a second polarization direction, and therefore the polarization beam splitter 342 can reflect the reflected light RL1 of the laser beam. Thus, the reflected light RL1 of the laser beam can be incident on the aberration sensor 348.

[0059] Therefore, the laser processing equipment 10 can use the optical path forming unit 341 to adjust the polarization direction of the laser beam L1, so that the laser beam L1 passing through the focusing lens 350 can be received by the aberration sensor 348.

[0060] Aberration sensor 348 can receive the laser beam transmitted through optical path forming section 341. Aberration sensor 348 can also receive the laser beam that has passed through focusing lens 350. As described below, aberration sensor 348 may include a wavefront sensor for measuring the wavefront of the received laser beam. Controller 40 can analyze the aberrations of the laser beam measured by aberration sensor 348, calculate correction values ​​to make the values ​​of each type of aberration approach zero, and output a control signal reflecting the correction values ​​to aberration corrector 332. Aberration corrector 332 can modulate the phase of laser beam L1 in response to the control signal. Therefore, aberrations of laser beam L1 can be eliminated, limited, or reduced.

[0061] like Figure 4As shown, in the processing mode for processing substrate W, the polarization beam splitter 342 and waveplate 346 can be placed outside the optical path between the aberration corrector 332 and the focusing lens 350. The polarization beam splitter 342 and waveplate 346 can be moved in a direction opposite to the first direction (-X direction) based on the operating mode. Therefore, the laser beam L1 can be focused onto the substrate W, which is the processing target, without passing through the polarization beam splitter 342 and waveplate 346. Therefore, the aberration sensor 348 can not receive reflected light from the laser beam L1.

[0062] The drive unit of the laser processing equipment 10 can move the laser beam L1 relative to the substrate W in a second horizontal direction different from the first horizontal direction (X direction) to scan the laser beam L1 along the cutting line S on the substrate W. For example, the second horizontal direction can be a direction perpendicular to the first horizontal direction (X direction) (Y direction).

[0063] Stage 20 can be moved in one direction at a predetermined (or optionally, desired) moving speed by stage driver 22. The scanning speed of laser beam L1 can be determined, for example, by or based on the moving speed of stage 20, but the example embodiment is not limited thereto. The scanning speed of laser beam L1 can be, for example, in the range of 300 mm / s to 2000 mm / s, but the example embodiment is not limited thereto.

[0064] like Figure 5A and Figure 5B As shown, the aberration sensor 348 may include a lenslet array LA and an image sensor IS. The aberration sensor 348 may include, for example, a Shack-Hartmann wavefront sensor. The pixels of the image sensor IS can detect multiple images formed by the lenslet array LA.

[0065] When a distortion-free wavefront passes through the microlens array LA, each location in the multiple images formed on the image sensor IS can be referred to as a reference spot. The wavefront PW of the laser beam L1 (e.g., the reflected light RL1 of the laser beam) incident on the microlens array LA of the aberration sensor 348 is distorted due to aberrations caused by the focusing lens 350; therefore, the focal points A and B detected by the pixels of the image sensor IS can change. The slope of the wavefront can be calculated by calculating the displacement difference between the reference spot and the changed spot at each pixel. A two-dimensional distribution map of the entire wavefront can be constructed based on the measured slope information. The measured wavefront can be extended to a Zernike polynomial. The coefficients of the Zernike polynomial can be calculated from the displacement difference. Each coefficient can represent a specific aberration.

[0066] The controller 40 can use the calculated coefficients to calculate a correction value that brings the value of each type of aberration close to zero, and can output a control signal reflecting the correction value to the aberration corrector 332. The aberration corrector 332 can modulate the phase of the laser beam L1 in response to the control signal. Each pixel of the spatial light modulator can have its optical properties individually adjusted to compensate for a specific aberration. For example, when correcting spherical aberration, the optical properties of the pixels at the center and the periphery of the spatial light modulator can be modulated differently, and when correcting coma aberration, the optical properties of the pixels on the left and right sides of the spatial light modulator can be modulated differently.

[0067] As described above, the laser processing apparatus 10 may include: a laser output unit 300 for outputting a laser beam L1; a focusing lens 350 for focusing the laser beam L1 onto a substrate W in processing mode and for focusing the laser beam L1 onto a reflective structure BW in measurement mode; an aberration measurement optical system 340 for measuring the aberrations of the laser beam by receiving reflected light RL1 from the laser beam from the reflective structure BW via the focusing lens 350; and an aberration corrector 332 for correcting the aberrations of the laser beam based on the aberration information of the measured laser beam.

[0068] The aberration measurement optical system 340 can measure the aberrations of the laser beam L1 that has passed through the focusing lens 350 in measurement mode, while not affecting the propagation of the laser beam L1 in processing mode. The aberration corrector 332 can adjust the phase of the laser beam L1 based on the measured aberration information to correct the aberrations of the laser beam L1, thereby improving the processing quality of the laser beam accordingly.

[0069] Figure 6 This is a block diagram illustrating a laser processing apparatus according to some example embodiments. Figure 7 It is shown in Figure 6 A block diagram of the measurement mode of the first laser beam executed in a laser processing device. Figure 8 It is shown in Figure 6 A block diagram of the measurement mode of the second laser beam executed in the laser processing equipment. Figure 9 It is shown in Figure 6 A block diagram of the processing mode performed in the laser processing equipment. Apart from the structure of the laser output section that outputs the first and second laser beams, and the structure of the aberration measurement optical system and aberration corrector, the laser processing equipment can be compared with a reference... Figures 1 to 4 The laser processing equipment described is the same or substantially the same. Therefore, the same reference numerals will be used to refer to the same or identical elements, and any further repetitive explanations regarding the above elements will be omitted.

[0070] Reference Figures 6 to 9 The laser irradiator 30 may include: a laser output unit 300 for outputting a first laser beam L1 and a second laser beam L2; a focusing lens 350 for focusing the first laser beam L1 and the second laser beam L2 onto a substrate W; and an aberration measurement optical system 340 for measuring the aberrations of the first laser beam L1 and the second laser beam L2 passing through the focusing lens 350. The laser irradiator 30 may also include a first aberration corrector 332a and a second aberration corrector 332b, wherein the first aberration corrector 332a is used to correct the aberration of the first laser beam L1 based on the aberration information of the measured first laser beam, and the second aberration corrector 332b is used to correct the aberration of the second laser beam L2 based on the aberration information of the measured second laser beam.

[0071] In some example embodiments, the laser output unit 300 may include a beam splitter 322 for splitting a laser beam L0 from a laser source 310 into a first laser beam L1 and a second laser beam L2. The laser output unit 300 may also include: a waveplate 320 for altering the polarization component of the laser beam L0 from the laser source 310; a first beam blocking portion 324a disposed in the optical path of the first laser beam L1 split by the beam splitter 322 to selectively block the first laser beam L1; and a second beam blocking portion 324b disposed in the optical path of the second laser beam L2 split by the beam splitter 322 to selectively block the second laser beam L2. For example, the waveplate 320 may include a half-waveplate. The beam splitter 322 may include a polarization beam splitter. The first beam blocking portion 324a and the second beam blocking portion 324b may include an optical shutter. In some example embodiments, the laser output unit 300 may also include mirrors 312, 315, and 316, but the example embodiments are not limited thereto.

[0072] For example, a laser beam L0 from a laser source 310 can pass through a waveplate 320. The waveplate 320 can change the polarization of the laser beam L0. For example, the waveplate 320 can adjust the polarization of the laser beam L0 such that the polarization components of the laser beam L0 include 50% P-polarization and 50% S-polarization, but the example embodiment is not limited thereto.

[0073] The laser beam L0 passing through the waveplate 320 can be split into a first laser beam L1 and a second laser beam L2 by the beam splitter 322 based on polarization. For example, the first laser beam L1 can be S-polarized and the second laser beam L2 can be P-polarized.

[0074] A first laser beam L1 can pass through a first aberration corrector 332a to a polarization beam splitter 328, and a second laser beam L2 can pass through a second aberration corrector 332b to a polarization beam splitter 328. A first beam blocking portion 324a can be disposed in a first optical path between the beam splitter 322 and the first aberration corrector 332a to selectively block the first laser beam L1. A second beam blocking portion 324b can be disposed in a second optical path between the beam splitter 322 and the second aberration corrector 332b to selectively block the second laser beam L2.

[0075] The polarization beam splitter 328 can transmit a first laser beam L1 having a first polarization direction (P-polarization) and can reflect a second laser beam L2 having a second polarization direction (S-polarization). The focusing lens 350 can focus the first laser beam L1 passing through the polarization beam splitter 328 onto the substrate W or the reflecting structure BW on the stage 20, and can focus the second laser beam L2 reflected by the polarization beam splitter 328 onto the substrate W or the reflecting structure BW on the stage 20.

[0076] In some example embodiments, a focus position adjuster 334 may be disposed in a first optical path of the first laser beam L1 and / or a second optical path of the second laser beam L2 to adjust the focus position P1 of the first laser beam L1 and / or the focus position P2 of the second laser beam L2. The focus position adjuster 334 may adjust the focus position P1 of the first laser beam L1 and the focus position P2 of the second laser beam L2 to be different from each other. The focus position adjuster 334 may include a spatial light modulator (SLM), but the example embodiments are not limited thereto.

[0077] The focus position adjuster 334 can be disposed in the second optical path of the second laser beam L2 and can modulate the phase of the second laser beam L2. Optionally, the focus position adjuster 334 can be disposed in the first optical path of the first laser beam L1. In addition, the first aberration corrector 332a and the second aberration corrector 332b can perform the function of the focus position adjuster, and in this case, the focus position adjuster 334 can be omitted.

[0078] A first laser beam L1 and a second laser beam L2 can be focused such that the focal positions P1 of the first laser beam L1 and P2 of the second laser beam L2 are different from each other. In the processing mode, the first laser beam L1 may have a focal position P1 at a first depth d1 from the surface of the substrate W, and the second laser beam L2 may have a focal position P2 at a second depth d2 from the surface of the substrate W that is greater than the first depth. Therefore, the focal positions P1 of the first laser beam L1 and P2 of the second laser beam L2 may have the same XY plane coordinates.

[0079] In some example embodiments, the aberration measurement optical system 340 can measure the aberrations of a first laser beam and a second laser beam by receiving reflected light RL1 from a first laser beam and reflected light RL2 from a second laser beam via a focusing lens 350. The aberration measurement optical system 340 may include an optical path forming unit 341 and an aberration sensor 348. The optical path forming unit 341 can guide the reflected light RL1 from the first laser beam propagating through the focusing lens 350 from the reflecting structure BW to the aberration sensor 348. The optical path forming unit 341 can transmit the first laser beam L1 and the second laser beam L2 provided from the laser output unit 300 to the focusing lens 350, and can transmit the reflected light RL1 and RL2 of the laser beam reflected by the reflecting structure BW after passing through the focusing lens 350 to the aberration sensor 348. The optical path forming unit 341 may include a polarization beam splitter 342, a quarter-wave plate 346, and a half-wave plate 347. The optical path forming section 341 may also include optical elements (such as at least one mirror, at least one lens, etc.).

[0080] The polarization beam splitter 342 can transmit a laser beam with a first polarization direction and reflect a laser beam with a second polarization direction perpendicular to the first polarization direction. A quarter-wave plate 346 can be disposed in the optical path between the polarization beam splitter 342 and the reflecting structure BW to change the polarization direction of the laser beam that has passed through the polarization beam splitter 342. A half-wave plate 347 can be disposed in the optical path of the second laser beam L2 incident from the laser output section 300 to the polarization beam splitter 342 to change the laser beam with the second polarization direction into a laser beam with the first polarization direction. The quarter-wave plate 346 and the half-wave plate 347 can be configured to be movable according to the operating mode of the laser processing equipment 10. The laser processing equipment 10 may include a moving mechanism for moving the quarter-wave plate 346 and the half-wave plate 347. The moving mechanism can move the quarter-wave plate 346 and the half-wave plate 347 based on a control signal from the controller 40.

[0081] like Figure 7 As shown, in a first measurement mode for measuring the aberrations of the first laser beam L1, a polarizing beam splitter 342 and a quarter-wave plate 346 can be positioned in the optical path between the polarizing beam splitter 328 and the focusing lens 350. The quarter-wave plate 346 can be moved in a first direction (X direction) based on the operating mode. The focusing lens 350 can converge (e.g., focus) the first laser beam L1, which has passed through the polarizing beam splitter 342, onto the reflecting structure BW supported on the stage 20. For example, the polarizing beam splitter 342, the quarter-wave plate 346, and the focusing lens 350 can be located on the same axis.

[0082] For example, the first beam blocking section 324a allows the passage of the first laser beam L1, and the second beam blocking section 324b blocks the second laser beam L2. Therefore, the laser output section 300 can output the first laser beam L1 with a first polarization direction (P-polarization), and the polarization beam splitter 342 can transmit the first laser beam L1 with the first polarization direction. The first laser beam L1 with the first polarization direction can pass through the quarter-wave plate 346 and then be incident on the reflecting structure BW. The reflected light RL1 of the first laser beam can pass through the quarter-wave plate 346 and be incident again on the polarization beam splitter 342. The quarter-wave plate 346 delays the phase of the light passing through it by 1 / 4 wavelength. As the laser beam passes through the quarter-wave plate 346 twice, the reflected light RL1 of the first laser beam that is incident again on the polarization beam splitter 342 can change to have a second polarization direction (S-polarization).

[0083] The polarization beam splitter 342 can reflect a laser beam with a second polarization direction, and therefore the polarization beam splitter 342 can reflect the reflected light RL1 of the first laser beam. Therefore, the reflected light RL1 of the first laser beam can be incident on the aberration sensor 348.

[0084] Therefore, the laser processing equipment 10 can use the optical path forming unit 341 to adjust the polarization direction of the first laser beam L1, so that the first laser beam L1 passing through the focusing lens 350 can be received by the aberration sensor 348.

[0085] Aberration sensor 348 measures the aberrations of the first laser beam L1 transmitted through the optical path forming section 341. Controller 40 analyzes the aberration information of the first laser beam measured by aberration sensor 348, calculates correction values ​​to bring the values ​​of each type of aberration close to zero, and outputs a control signal reflecting the correction values ​​to first aberration corrector 332a. First aberration corrector 332a modulates the phase of the first laser beam L1 in response to the control signal. Therefore, the aberrations of the first laser beam L1 can be eliminated, limited, or reduced.

[0086] like Figure 8 As shown, in the second measurement mode for measuring the aberrations of the second laser beam L2, a half-wave plate 347, a polarizing beam splitter 342, and a quarter-wave plate 346 can be positioned in the optical path between the polarizing beam splitter 328 and the focusing lens 350. The half-wave plate 347 and the quarter-wave plate 346 can be moved in a first direction (X direction) based on the operating mode. The focusing lens 350 can converge (e.g., focus) the second laser beam L2, which has passed through the polarizing beam splitter 342, onto the reflecting structure BW supported on the stage 20. For example, the half-wave plate 347, the polarizing beam splitter 342, the quarter-wave plate 346, and the focusing lens 350 can be located on the same axis.

[0087] For example, the first beam blocking part 324a can block the first laser beam L1, and the second beam blocking part 324b can allow the second laser beam L2 to pass through. Therefore, the laser output part 300 can output a second laser beam L2 having a second polarization direction (S-polarization), and the second laser beam L2 can pass through the half-wave plate 347 and then be incident on the polarization beam splitter 342. The polarization of the second laser beam L2 can change as it passes through the half-wave plate 347. The second laser beam L2 that has passed through the half-wave plate 347 can have a first polarization direction (P-polarization). The polarization beam splitter 342 can transmit the second laser beam L2 having the first polarization direction.

[0088] A second laser beam L2 with a first polarization direction can pass through a quarter-wave plate 346 and be incident on the reflective structure BW. The reflected light RL2 of the second laser beam can also pass through the quarter-wave plate 346 and be re-incident on the polarization beam splitter 342. The quarter-wave plate 346 delays the phase of the light passing through it by 1 / 4 wavelength. As the laser beam passes through the quarter-wave plate 346 twice, the reflected light RL2 of the second laser beam that is re-incident on the polarization beam splitter 342 can be changed to have a second polarization direction (S-polarization).

[0089] Since the polarization beam splitter 342 reflects the laser beam with a second polarization direction, it can reflect the reflected light RL2 of the second laser beam. Therefore, the reflected light RL2 of the second laser beam can be incident on the aberration sensor 348.

[0090] Therefore, the laser processing equipment 10 can use the optical path forming unit 341 to adjust the polarization direction of the second laser beam L2, so that the second laser beam L2 passing through the focusing lens 350 can be received by the aberration sensor 348.

[0091] Aberration sensor 348 measures the aberrations of the second laser beam L2 transmitted through the optical path forming section 341. Controller 40 analyzes the aberration information of the second laser beam measured by aberration sensor 348, calculates correction values ​​to bring the values ​​of each type of aberration close to zero, and outputs a control signal reflecting the correction values ​​to second aberration corrector 332b. Second aberration corrector 332b modulates the phase of the second laser beam L2 in response to the control signal. Therefore, the aberrations of the second laser beam L2 can be eliminated or reduced.

[0092] like Figure 9 As shown, in the processing mode for processing substrate W, polarization beam splitter 342, quarter-wave plate 346, and half-wave plate 347 can be placed outside the optical path between polarization beam splitter 328 and focusing lens 350. Focusing lens 350 can converge (e.g., focus) the first laser beam L1 and the second laser beam L2 that have passed through polarization beam splitter 328 onto substrate W supported on stage 20.

[0093] For example, the first beam blocking part 324a allows the passage of the first laser beam L1, and the second beam blocking part 324b allows the passage of the second laser beam L2. The first aberration corrector 332a can modulate the phase of the first laser beam L1 in response to a control signal from the controller 40, and the second aberration corrector 332b can modulate the phase of the second laser beam L2 in response to a control signal from the controller 40.

[0094] The polarization beam splitter 342, quarter-wave plate 346, and half-wave plate 347 can be moved in the opposite direction (-X direction) based on the operating mode. Therefore, the first laser beam L1 and the second laser beam L2 can be focused onto the substrate W, which is the processing target, without passing through the polarization beam splitter 342, quarter-wave plate 346, and half-wave plate 347. The aberration sensor 348 may not receive reflected light from the laser beams L1 and L2.

[0095] The drive unit of the laser processing equipment 10 can move a first laser beam L1 and a second laser beam L2 relative to the substrate W in a second horizontal direction (Y direction) different from the first horizontal direction (X direction) to scan the first laser beam L1 and the second laser beam L2 along the cutting line S on the substrate W. The first laser beam L1 and the second laser beam L2 can be focused such that the focal position P1 of the first laser beam L1 and the focal position P2 of the second laser beam L2 are different from each other. In the processing mode of the substrate W, the first laser beam L1 may have a focal position P1 at a first depth d1 from the surface of the substrate W, and the second laser beam L2 may have a focal position P2 at a second depth d2 from the surface of the substrate W that is greater than the first depth. Here, the focal position P1 of the first laser beam L1 and the focal position P2 of the second laser beam L2 may have the same XY plane coordinates.

[0096] Figure 10 This is a block diagram illustrating a laser processing apparatus according to an example embodiment. Figure 11 It is shown in Figure 10 A block diagram of the measurement mode of the first laser beam executed in a laser processing device. Figure 12 It is shown in Figure 10 A block diagram of the measurement mode of the second laser beam executed in the laser processing equipment. Figure 13 It is shown in Figure 10 A block diagram of the processing mode performed in the laser processing equipment. Apart from the structure of the laser output section that outputs the first and second laser beams and the structure of the aberration measurement optical system, the laser processing equipment can be compared with a reference... Figures 6 to 9 The laser processing equipment described is essentially the same. Therefore, the same reference numerals will be used to refer to the same or identical elements, and any further repetitive explanations regarding the above elements will be omitted.

[0097] Reference Figures 10 to 13 The laser irradiator 30 may include: a laser output unit 300 for outputting a first laser beam L1 and a second laser beam L2; a focusing lens 350 for focusing the first laser beam L1 and the second laser beam L2 onto a substrate W; and an aberration measurement optical system 340 for measuring the aberrations of the first laser beam L1 and the second laser beam L2 passing through the focusing lens 350. The laser output unit 300 may also include a laser measurement unit 360 configured to measure the waveform, power, etc., of the laser beam output from the laser source 310. In some example embodiments, the laser output unit 300 may also include mirrors 312, 314, 315, and 316, but the example embodiments are not limited thereto.

[0098] In some example embodiments, a portion of the laser beam L0 output from the laser source 310 may be reflected by beam splitters 311 and 313 and guided to the laser measurement unit 360. The laser measurement unit 360 may include a pulse monitor 362 for measuring the waveform of the laser beam and a power meter 364 for measuring the power of the laser beam. The pulse monitor 362 measures the waveform of the laser beam L0 reflected by beam splitter 311. The power meter 364 measures the power of the laser beam L0 that has passed through beam splitter 311 and subsequently been reflected by mirror 312 and beam splitter 313. For example, each of beam splitters 311 and 313 may have 99% transmittance and 1% reflectance, but the example embodiments are not limited thereto.

[0099] The laser beam L0, having passed through beam splitters 311 and 313, can pass through waveplate 320. Waveplate 320 can change the polarization of the laser beam L0. For example, waveplate 320 can adjust the polarization of the laser beam L0 so that the polarization components of the laser beam L0 have 50% P-polarization and 50% S-polarization. The laser beam L0, having passed through waveplate 320, can be split into a first laser beam L1 and a second laser beam L2 based on polarization by polarization beam splitter 322. For example, the first laser beam L1 can be S-polarized, and the second laser beam L2 can be P-polarized.

[0100] In some example embodiments, the aberration measurement optical system 340 may include an optical path forming unit 341 and an aberration sensor 348. The optical path forming unit 341 can transmit a first laser beam L1 and a second laser beam L2 provided from the laser output unit 300 to a focusing lens 350, and can transmit the reflected light RL1, RL2 of the laser beams that are reflected by the reflecting structure BW after passing through the focusing lens 350 to the aberration sensor 348. The optical path forming unit 341 may include a polarization beam splitter 342, a reflection beam splitter 344, and a quarter-wave plate 346.

[0101] For example, a first laser beam L1 may pass through a first aberration corrector 332a to a polarizing beam splitter 342 of the aberration measurement optical system 340, and a second laser beam L2 may pass through a second aberration corrector 332b to a polarizing beam splitter 342 of the aberration measurement optical system 340. For example, the first laser beam L1 may be incident on a first surface of the polarizing beam splitter 342 along a vertical direction (Z direction), and the second laser beam L2 may be incident on a second surface of the polarizing beam splitter 342 along a first horizontal direction (X direction). The first surface of the polarizing beam splitter 342 may be perpendicular to the vertical direction (Z direction), and the second surface of the polarizing beam splitter 342 may be adjacent to the first surface and perpendicular to the first horizontal direction (X direction).

[0102] Polarizing beam splitter 342 can transmit a laser beam having a first polarization direction and can reflect a laser beam having a second polarization direction perpendicular to the first polarization direction. Reflecting beam splitter 344 can reflect a portion of the laser beam having the second polarization direction and can transmit another portion. Reflecting beam splitter 344 can be, for example, a cube beam splitter, but the example embodiment is not limited thereto. A quarter-wave plate 346 can be disposed in the optical path between polarizing beam splitter 342 and reflecting structure BW to change the polarization direction of the laser beam transmitted through polarizing beam splitter 342. Reflecting beam splitter 344 and quarter-wave plate 346 can be configured to be movable according to the operating mode of laser processing apparatus 10. Laser processing apparatus 10 may include a moving mechanism for moving reflecting beam splitter 344 and quarter-wave plate 346. The moving mechanism can move reflecting beam splitter 344 and quarter-wave plate 346 based on control signals from controller 40.

[0103] like Figure 11 As shown, in a first measurement mode for measuring the aberrations of the first laser beam L1, a polarizing beam splitter 342 and a quarter-wave plate 346 can be positioned in the optical path between the first aberration corrector 332a and the focusing lens 350. The quarter-wave plate 346 can be moved in a first direction (X direction) based on the operating mode. The focusing lens 350 can converge (e.g., focus) the first laser beam L1, which has passed through the polarizing beam splitter 342, onto the reflecting structure BW supported on the stage 20. For example, the polarizing beam splitter 342, the quarter-wave plate 346, and the focusing lens 350 can be positioned on the same axis.

[0104] For example, the first beam blocking section 324a allows the passage of the first laser beam L1, and the second beam blocking section 324b blocks the second laser beam L2. Therefore, the laser output section 300 can output the first laser beam L1 with a first polarization direction (P-polarization), and the polarization beam splitter 342 can transmit the first laser beam L1 with the first polarization direction. The first laser beam L1 with the first polarization direction can pass through the quarter-wave plate 346 and then be incident on the reflecting structure BW. The reflected light RL1 of the first laser beam can pass through the quarter-wave plate 346 and be incident again on the polarization beam splitter 342. The quarter-wave plate 346 delays the phase of the light passing through it by 1 / 4 wavelength. As the laser beam passes through the quarter-wave plate 346 twice, the reflected light RL1 of the first laser beam that is incident again on the polarization beam splitter 342 can change to have a second polarization direction (S-polarization).

[0105] The polarization beam splitter 342 can reflect a laser beam with a second polarization direction, and therefore the polarization beam splitter 342 can reflect the reflected light RL1 of the first laser beam. Therefore, the reflected light RL1 of the first laser beam can be incident on the aberration sensor 348.

[0106] like Figure 12 As shown, in the second measurement mode for measuring the aberrations of the second laser beam L2, the polarization beam splitter 342 and the reflection beam splitter 344 can be positioned in the optical path between the second aberration corrector 332b and the focusing lens 350. The reflection beam splitter 344 can be moved in the vertical direction (Z direction) based on the operating mode. The focusing lens 350 can converge (e.g., focus) the second laser beam L2, which has passed through the reflection beam splitter 344 and the polarization beam splitter 342, onto the reflecting structure BW supported on the stage 20.

[0107] For example, the first beam blocking part 324a can block the first laser beam L1, and the second beam blocking part 324b can allow the second laser beam L2 to pass through. Therefore, the laser output part 300 can output the second laser beam L2 with a second polarization direction (S polarization), and the second laser beam L2 can pass through the reflective beam splitter 344 and then be incident on the polarization beam splitter 342.

[0108] A portion of the second laser beam L2, having a second polarization direction, can pass through the reflecting beam splitter 344, be reflected by the polarizing beam splitter 342, and then be incident on the reflecting structure BW. The reflected light RL2 of the second laser beam can then be incident on the polarizing beam splitter 342 again. Since the polarizing beam splitter 342 reflects the laser beam with the second polarization direction, it can also reflect the reflected light RL2 of the second laser beam. Therefore, the reflected light RL2 of the second laser beam can be incident on the reflecting beam splitter 344. Since the reflecting beam splitter 344 reflects a portion of the laser beam with the second polarization direction, a portion of the reflected light RL2 of the second laser beam can also be reflected by the reflecting beam splitter 344. Therefore, this portion of the reflected light RL2 of the second laser beam can be received by the aberration sensor 348 after being reflected by the mirror 317.

[0109] like Figure 13 As shown, in the processing mode for processing substrate W, the reflecting beam splitter 344 can be disposed outside the optical path between the second aberration corrector 332b and the polarizing beam splitter 342, and the quarter-wave plate 346 can be disposed outside the optical path between the polarizing beam splitter 342 and the focusing lens 350. The focusing lens 350 can converge (e.g., focus) the first laser beam L1 that has passed through the polarizing beam splitter 342 onto the substrate W supported on the stage 20, and can converge (e.g., focus) the second laser beam L2 reflected by the polarizing beam splitter 342 onto the substrate W supported on the stage 20.

[0110] For example, the first beam blocking part 324a allows the passage of the first laser beam L1, and the second beam blocking part 324b allows the passage of the second laser beam L2. The first aberration corrector 332a can modulate the phase of the first laser beam L1 in response to a control signal from the controller 40, and the second aberration corrector 332b can modulate the phase of the second laser beam L2 in response to a control signal from the controller 40.

[0111] The reflective beam splitter 344 can move in the direction opposite to the vertical direction (-Z direction) based on the operating mode, and the quarter-wave plate 346 can move in the direction opposite to the first direction (-X direction) based on the operating mode. Therefore, the first laser beam L1 can be focused onto the substrate W, which is the object to be processed, without passing through the quarter-wave plate 346, and the second laser beam L2 can be focused onto the substrate W, which is the object to be processed, without passing through the reflective beam splitter 344 and the quarter-wave plate 346.

[0112] The following will describe the use of Figure 2 , Figure 6 and Figure 10 Laser processing methods for laser processing equipment.

[0113] Figure 14 This is a flowchart illustrating a laser processing method according to an example embodiment. Figure 15 It is a cross-sectional view showing a wafer irradiated by both a first laser beam and a second laser beam. Figure 16 This is a plan view showing the scan lines on the wafer. Figure 15 The first and second laser beams scan along the scanning line.

[0114] Reference Figures 1 to 16 First, the reflective structure BW can be supported on the stage 20 (S10); laser beams L1 and L2 can be emitted (S20); the laser beams L1 and L2 can be focused on the reflective structure BW (e.g., focused onto the reflective structure BW) by the focusing lens 350 (S30); the reflected light RL1 and RL2 from the laser beams from the reflective structure BW can be received by the focusing lens 350 (S40); and the aberrations of the laser beams L1 and L2 can be corrected based on the aberration information of the received reflected light RL1 and RL2 (S50).

[0115] In some example embodiments, stage 20 may support a substrate W, which is the processing target, and a reflective structure BW for measuring the laser beam. Stage 20 may move the substrate W and the reflective structure BW based on the operating mode. Stage 20 may position the reflective structure BW at the focal point of focusing lens 350 in the measurement mode of laser beams L1, L2. Focusing lens 350 may converge (e.g., focus) the laser beams L1, L2 from laser output section 300 onto the reflective structure BW on stage 20.

[0116] The aberration measurement optical system 340 measures the aberrations of a laser beam by receiving reflected light RL1 and RL2 from the laser beam of the reflecting structure BW via the focusing lens 350. The aberration measurement optical system 340 may include an optical path forming unit 341 and an aberration sensor 348. The optical path forming unit 341 guides the reflected light RL1 and RL2 from the laser beam passing through the focusing lens 350 from the reflecting structure BW to the aberration sensor 348. The laser processing apparatus 10 can use the optical path forming unit 341 to adjust the polarization direction of the laser beams L1 and L2 so that the aberration sensor 348 can receive the laser beams L1 and L2 that have passed through the focusing lens 350.

[0117] Aberration correctors 332, 332a, and 332b can be disposed in the optical path of the laser beams L1 and L2 incident from the laser output section 300 to the focusing lens 350, and can correct the aberrations of the laser beams. Aberration correctors 332, 332a, and 332b can correct the aberrations of the laser beams L1 and L2 based on the aberration information of the laser beams measured by the aberration measurement optical system 340.

[0118] The controller 40 analyzes the aberrations of the laser beam measured by the aberration sensor 348, calculates correction values ​​that bring the value of each type of aberration close to zero, and outputs control signals reflecting the aberrations to the aberration correctors 332, 332a, and 332b. The aberration correctors 332, 332a, and 332b modulate the phase of the laser beams L1 and L2 in response to the control signals. Therefore, the aberrations of the laser beams L1 and L2 can be eliminated or reduced.

[0119] Then, the substrate W, which is the processing target, can be placed on the stage 20 (S60), and the laser beams L1 and L2 with corrected aberrations (e.g., their aberrations are corrected) can be focused on the substrate W by the focusing lens 350 (S70), and the laser beams L1 and L2 can be scanned along the cutting line S on the substrate W (e.g., the cutting line S of the substrate W) (S80).

[0120] In some example embodiments, stage 20 can position substrate W at the focal point of focusing lens 350 in the processing mode of laser beams L1, L2. Focusing lens 350 can converge (e.g., focus) the laser beams L1, L2 from laser output section 300 onto substrate W on stage 20.

[0121] The drive unit of the laser processing equipment 10 can move the laser beams L1 and L2 relative to the substrate W in a second horizontal direction (Y direction) different from the first horizontal direction (X direction) to scan the laser beams L1 and L2 along the cutting line S on the substrate W. For example, the second horizontal direction can be a direction perpendicular to the first horizontal direction (X direction) (Y direction).

[0122] In some example embodiments, the laser output unit 300 may include a beam splitter 322 for splitting a laser beam L0 from the laser source 310 into a first laser beam L1 and a second laser beam L2. A focus position adjuster 334 may be disposed on a first optical path of the first laser beam L1 and / or a second optical path of the second laser beam L2 to adjust the focus position P1 of the first laser beam L1 and / or the focus position P2 of the second laser beam L2. The focus position adjuster 334 may adjust the focus position P1 of the first laser beam L1 and the focus position P2 of the second laser beam L2 to be different from each other.

[0123] like Figure 15 and Figure 16 As shown, in the processing mode, the first laser beam L1 may have a focal position P1 at a first depth d1 from the surface of the substrate W, and the second laser beam L2 may have a focal position P2 at a second depth d2 from the surface of the substrate W that is greater than the first depth. Here, the focal position P1 of the first laser beam L1 and the focal position P2 of the second laser beam L2 may have the same XY plane coordinates.

[0124] When a first laser beam L1 and a second laser beam L2 with different depths d1 and d2 are focused within a substrate W, local melting (melting), expansion, contraction, and solidification processes can occur at a first spot (e.g., a first focal position) P1 and a second spot (e.g., a second focal position) P2. During the contraction process, the left and right regions of the first spot P1 and the second spot P2 can contract first, causing cracks to form at the center of the first spot P1 and the second spot P2, and when the contraction ends, the cracks can grow vertically to form vertical cracks. Through the above process, when the first laser beam L1 and the second laser beam L2 intermittently irradiate the substrate W while moving relative to the substrate W along a cutting line S on the substrate W, an invisible cutting line can be formed inside the substrate W along the cutting line S (e.g., along a second horizontal direction (Y direction)).

[0125] Semiconductor packages formed by the aforementioned laser processing equipment may include semiconductor devices (such as logic devices or memory devices). Semiconductor packages may include logic devices (such as central processing units (CPUs), main processors (MPUs), or application processors (APs), as well as volatile memory devices (such as DRAM devices, HBM devices) and / or non-volatile memory devices (such as flash memory devices, PRAM devices, MRAM devices, ReRAM devices, etc.).

[0126] The foregoing is a description of some exemplary embodiments and is not to be construed as limiting them. Although some exemplary embodiments have been described, those skilled in the art will readily understand that many modifications are possible in the exemplary embodiments without substantially departing from the novel teachings and advantages of the inventive concept. Therefore, all such modifications are intended to be included within the scope of the exemplary embodiments as defined in the claims.

[0127] One or more of the elements disclosed above may include or be implemented in a processing circuitry system (such as hardware including logic circuitry; a hardware / software combination (such as a processor executing software); or a combination thereof). For example, the processing circuitry system may more specifically include, but is not limited to, a central processing unit (CPU), an arithmetic logic unit (ALU), a digital signal processor, a microcomputer, a field-programmable gate array (FPGA), a system-on-a-chip (SoC), a programmable logic unit, a microprocessor, an application-specific integrated circuit (ASIC), etc.

Claims

1. A laser processing apparatus comprising: a stage configured to support a substrate as a processing target and to support a reflection structure for measurement; a laser output configured to output a laser beam; a focusing lens configured to focus the laser beam onto the substrate in a processing mode for processing the substrate and to focus the laser beam onto the reflection structure in a measurement mode for measuring the laser beam; an aberration measurement optical system configured to receive light of the laser beam reflected by the reflection structure through the focusing lens and to measure an aberration of the laser beam; and an aberration corrector configured to correct the aberration of the laser beam based on measured aberration information of the laser beam on an optical path of the laser beam from the laser output to the focusing lens. The aberration measurement optical system comprises:

2. The laser processing apparatus according to claim 1, wherein a polarization beam splitter configured to transmit the laser beam having a first polarization direction and to reflect the laser beam having a second polarization direction perpendicular to the first polarization direction; a wave plate on an optical path between the polarization beam splitter and the reflection structure and configured to change a polarization direction of the laser beam transmitted through the polarization beam splitter; and an aberration sensor configured to receive light of the laser beam reflected by the polarization beam splitter and to measure an aberration of the laser beam, and wherein the polarization beam splitter and the wave plate are movable to be outside the optical path of the laser beam in the processing mode and to be on the optical path of the laser beam in the measurement mode. In the measurement mode, 3. The laser processing apparatus according to claim 2, wherein the laser beam having the first polarization direction passes through the polarization beam splitter and passes through the wave plate before being focused onto the reflection structure by the focusing lens, and the light of the laser beam reflected by the reflection structure passes through the focusing lens and passes through the wave plate and is reflected by the polarization beam splitter before being incident on the aberration sensor. The wave plate includes a quarter wave plate.

4. The laser processing apparatus according to claim 3, wherein The laser beam includes a first laser beam having the first polarization direction and a second laser beam having the second polarization direction perpendicular to the first polarization direction, the measurement mode of the laser beam includes a measurement mode for the first laser beam and a measurement mode for the second laser beam, 5. The laser processing apparatus according to claim 1, wherein wherein the aberration measurement optical system comprises: a polarization beam splitter configured to transmit the laser beam having a first polarization direction and to reflect the laser beam having a second polarization direction; a quarter wave plate on an optical path between the polarization beam splitter and the reflection structure, the quarter wave plate being configured to change a polarization direction of the laser beam transmitted through the polarization beam splitter; a half wave plate configured to change the laser beam having the second polarization direction to the laser beam having the first polarization direction when on an optical path of the laser beam from the laser output to the polarization beam splitter; and an aberration sensor configured to measure an aberration of the laser beam by receiving light of the laser beam reflected by the polarization beam splitter, and wherein the polarization beam splitter, the quarter wave plate, and the half wave plate are movable to be outside the optical path of the laser beam in the processing mode; the polarization beam splitter and the quarter wave plate are movable to be on the optical path of the first laser beam in the measurement mode for the first laser beam; and the polarization beam splitter, the quarter wave plate, and the half wave plate are movable to be on the optical path of the second laser beam in the measurement mode for the second laser beam. 6.The laser processing apparatus according to claim 5, wherein, ​ In the measurement mode of the first laser beam, the first laser beam passes through the polarization beam splitter, passes through the quarter wave plate, and is focused onto the reflective structure by the focusing lens, and the light of the first laser beam reflected by the reflective structure passes through the focusing lens and the quarter wave plate, is reflected by the polarization beam splitter in this order, and then is incident on the aberration sensor; and In the measurement mode of the second laser beam, the second laser beam passes through the half wave plate, passes through the polarization beam splitter, passes through the quarter wave plate, and is focused onto the reflective structure by the focusing lens, and the light of the second laser beam reflected by the reflective structure passes through the focusing lens and the quarter wave plate, is reflected by the polarization beam splitter in this order, and then is incident on the aberration sensor.

7. The laser processing apparatus according to claim 1, wherein The laser beam includes a first laser beam having a first polarization direction and a second laser beam having a second polarization direction perpendicular to the first polarization direction, the measurement mode for the laser beam includes a measurement mode for the first laser beam and a measurement mode for the second laser beam, wherein the aberration measurement optical system includes: a polarization beam splitter configured to transmit the laser beam having the first polarization direction and to reflect the laser beam having the second polarization direction; a beam splitter configured to reflect a part of the laser beam having the second polarization direction and to transmit another part of the laser beam having the second polarization direction; a quarter wave plate configured to change the polarization direction of the laser beam transmitted through the polarization beam splitter when on an optical path between the polarization beam splitter and the reflective structure; and an aberration sensor configured to receive the reflected light of the laser beam reflected by the polarization beam splitter and to measure an aberration of the laser beam, and wherein the beam splitter and the quarter wave plate are movable to be outside of the optical path of the laser beam in the machining mode, the beam splitter and the quarter wave plate are movable to be on the optical path of the first laser beam in the measurement mode of the first laser beam, and the beam splitter is movable to be on the optical path of the second laser beam in the measurement mode of the second laser beam.

8. The laser machining apparatus according to claim 7, wherein, in the measurement mode of the first laser beam, the first laser beam passes through the polarization beam splitter, passes through the quarter wave plate, and is focused onto the reflective structure by the focusing lens, and the light of the first laser beam reflected by the reflective structure passes through the focusing lens and the quarter wave plate, is reflected by the polarization beam splitter and the beam splitter in this order, and then is incident on the aberration sensor; and in the measurement mode of the second laser beam, the second laser beam passes through the beam splitter, is reflected by the polarization beam splitter, and is focused onto the reflective structure by the focusing lens, and the light of the second laser beam reflected by the reflective structure is reflected by the polarization beam splitter and the beam splitter in this order, and then is incident on the aberration sensor.

9. The laser processing apparatus according to claim 1, wherein The aberration corrector includes a spatial light modulator configured to adjust a phase of the laser beam.

10. The laser processing apparatus according to claim 1, wherein The reflective structure includes a silicon wafer.

11. A laser machining apparatus, comprising: a stage configured to support a substrate as a machining target and to support a reflective structure for measurement; a laser output configured to output a first laser beam having a first polarization direction and a second laser beam having a second polarization direction perpendicular to the first polarization direction; The focusing lens is configured to focus the first laser beam and the second laser beam onto the substrate in a processing mode for processing the substrate, and to focus the first laser beam and the second laser beam onto the reflection structure, respectively, in a measurement mode for measuring the first laser beam and the second laser beam. The aberration measurement optical system is configured to receive, by the focusing lens, light of each of the first laser beam and the second laser beam reflected by the reflection structure, and to measure an aberration of each of the first laser beam and the second laser beam. The first aberration corrector is configured to correct an aberration of the first laser beam based on the measured aberration information of the first laser beam, on an optical path of the first laser beam from the laser output portion to the focusing lens. And The second aberration corrector is configured to correct an aberration of the second laser beam based on the measured aberration information of the second laser beam, on an optical path of the second laser beam from the laser output portion to the focusing lens.

12. The laser processing apparatus according to claim 11, wherein The aberration measurement optical system includes: a polarization beam splitter configured to transmit a laser beam having a first polarization direction and to reflect a laser beam having a second polarization direction; a quarter wave plate configured to change a polarization direction of a laser beam transmitted through the polarization beam splitter, on an optical path between the polarization beam splitter and the reflection structure; a half wave plate configured to change a laser beam having the second polarization direction to a laser beam having the first polarization direction, when on an optical path of the laser beam from the laser output portion to the polarization beam splitter; and an aberration sensor configured to receive light of the laser beam reflected by the polarization beam splitter, and to measure an aberration of the laser beam.

13. The laser processing apparatus according to claim 12, wherein The polarization beam splitter, the quarter wave plate, and the half wave plate are outside the optical path of the laser beam in the processing mode, the polarization beam splitter and the quarter wave plate are on the optical path of the first laser beam in the measurement mode of the first laser beam, and the polarization beam splitter, the quarter wave plate, and the half wave plate are on the optical path of the second laser beam in the measurement mode of the second laser beam.

14. The laser processing apparatus according to claim 11, wherein The aberration measurement optical system includes: a polarization beam splitter configured to transmit a laser beam having a first polarization direction and to reflect a laser beam having a second polarization direction; a beam splitter configured to reflect a part of a laser beam having the second polarization direction and to transmit another part of the laser beam having the second polarization direction; a quarter wave plate configured to change a polarization direction of a laser beam transmitted through the polarization beam splitter, on an optical path between the polarization beam splitter and the reflection structure; and an aberration sensor configured to receive light of the laser beam reflected by the polarization beam splitter, and to measure an aberration of the laser beam.

15. The laser processing apparatus according to claim 14, wherein The beam splitter and the quarter wave plate are outside the optical path of the laser beam in the processing mode, the polarization beam splitter, the beam splitter, and the quarter wave plate are on the optical path of the first laser beam in the measurement mode of the first laser beam, and the polarization beam splitter and the beam splitter are on the optical path of the second laser beam in the measurement mode of the second laser beam.

16. The laser processing apparatus according to claim 11, wherein The first aberration corrector includes a spatial light modulator configured to adjust a phase of the first laser beam, and the second aberration corrector includes a spatial light modulator configured to adjust a phase of the second laser beam.

17. The laser processing apparatus according to claim 11, wherein In the processing mode, the first laser beam has a focal point position at a first depth from a surface of the substrate, and the second laser beam has a focal point position at a second depth from the surface of the substrate, the second depth being greater than the first depth.

18. The laser processing apparatus according to claim 11, wherein, The reflective structure includes a mirror having a thickness smaller than a thickness of the substrate.

19. The laser processing apparatus according to claim 18, wherein The anti-reflection layer is on a surface of the mirror.

20. A laser processing apparatus comprising: a stage configured to support a reflective structure; a laser output configured to output a laser beam; a focusing lens configured to focus the laser beam on the reflective structure; an aberration measurement optical system configured to receive, by the focusing lens, light of the laser beam reflected by the reflective structure to measure an aberration of the laser beam; and an aberration corrector on an optical path of the laser beam from the laser output to the focusing lens, the aberration corrector being configured to correct the aberration of the laser beam based on the measured aberration information of the laser beam, wherein the aberration measurement optical system includes: a polarization beam splitter configured to transmit the laser beam having a first polarization direction and to reflect the laser beam having a second polarization direction perpendicular to the first polarization direction; at least one wave plate configured to change a polarization direction of the laser beam transmitted through the polarization beam splitter when on the optical path between the polarization beam splitter and the reflective structure; and an aberration sensor configured to receive the light of the laser beam reflected by the polarization beam splitter, the aberration sensor being configured to measure the aberration of the laser beam, wherein the at least one wave plate is configured to be able to be on the optical path of the laser beam or outside the optical path of the laser beam. ​

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