WO2024034193A1 - Dispositif de traitement laser et procédé de traitement laser - Google Patents

Dispositif de traitement laser et procédé de traitement laser Download PDF

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Publication number
WO2024034193A1
WO2024034193A1 PCT/JP2023/015987 JP2023015987W WO2024034193A1 WO 2024034193 A1 WO2024034193 A1 WO 2024034193A1 JP 2023015987 W JP2023015987 W JP 2023015987W WO 2024034193 A1 WO2024034193 A1 WO 2024034193A1
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Prior art keywords
optical axis
light
laser
wafer
laser processing
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PCT/JP2023/015987
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English (en)
Japanese (ja)
Inventor
知巳 荒谷
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浜松ホトニクス株式会社
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Publication of WO2024034193A1 publication Critical patent/WO2024034193A1/fr

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K26/00—Working by laser beam, e.g. welding, cutting or boring
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K26/00—Working by laser beam, e.g. welding, cutting or boring
    • B23K26/02—Positioning or observing the workpiece, e.g. with respect to the point of impact; Aligning, aiming or focusing the laser beam
    • B23K26/06—Shaping the laser beam, e.g. by masks or multi-focusing
    • B23K26/064—Shaping the laser beam, e.g. by masks or multi-focusing by means of optical elements, e.g. lenses, mirrors or prisms
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
    • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
    • H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26

Definitions

  • One aspect of the present invention relates to a laser processing device and a laser processing method.
  • a laser processing device that forms a modified region on an object by irradiating the object with laser light (for example, see Patent Document 1).
  • Such a laser processing device includes, for example, a support part that supports an object, a light source that emits laser light, a spatial light modulator that modulates the laser light emitted from the light source, and a spatial light modulator that modulates the laser light emitted from the light source. and a condensing section that condenses the laser beam.
  • the modulation pattern set in the spatial light modulator is set based on, for example, simulation, and is optimized through actual processing.
  • the modulation pattern is optimized by the above method, it may not be possible to perform desired laser processing using the modulation pattern due to various factors.
  • One aspect of the present invention has been made in view of the above circumstances, and an object of the present invention is to provide a laser processing device and a laser processing method that can perform desired laser processing.
  • a laser processing apparatus includes a support part that supports a wafer having a first surface and a second surface, a light source that emits laser light, and a spatial light modulator that modulates the laser light that is emitted from the light source.
  • a light-concentrating section that focuses the laser beam modulated by the spatial light modulator onto the wafer from the first surface side of the wafer; a moving part that moves relative to the first surface; an imaging part that acquires a captured image by detecting light propagated through the wafer via a light condensing part;
  • a first process that controls the moving unit to move relative to the first surface; and a second process that controls the light source so that the laser beam is continuously emitted while the first process is being performed.
  • a fourth process of acquiring an optical axis profile which is a profile image of the laser beam along the optical axis direction, by combining a plurality of captured images sequentially acquired in the third process. and a control unit.
  • laser light is irradiated while moving the light condensing part in the optical axis direction, and the light reflected on the second surface of the wafer is detected to continuously produce a plurality of captured images. is obtained.
  • a plurality of captured images are combined to obtain an optical axis profile that is a profile image of laser light along the optical axis direction. In this way, while moving the focal point of the laser beam in the optical axis direction (in the depth direction of the wafer), the reflected light from the second surface, which is the back surface of the wafer, is detected, and the above optical axis profile is obtained.
  • the irradiation state of the laser light along the optical axis direction for example, the position and intensity of the condensing point
  • the irradiation state of the laser light along the optical axis direction for example, the position and intensity of the condensing point
  • the convergence state of the laser internal processing can be grasped without actually performing laser processing on the wafer (before laser processing), and optimization of the modulation pattern can be realized. be able to.
  • control unit may further execute a fifth process of adjusting the modulation pattern of the spatial light modulator based on the optical axis profile acquired in the fourth process.
  • the modulation pattern can be optimized in consideration of the optical axis profile, and desired laser processing can be performed more appropriately. That is, the information on the focused state of the laser internal processing that has already been obtained can be fed back to the modulation pattern generation, and the desired laser processing can be performed.
  • the wafer is configured to include a birefringent material
  • the control unit determines the focal point related to the ordinary ray and the extraordinary ray based on the optical axis profile.
  • a modulation pattern is created so that the intensity of light at one of the two identified focal points increases and the intensity of light at the other focal point decreases. May be adjusted.
  • these incident lights are divided into ordinary rays and extraordinary rays, but the extraordinary rays do not follow Snell's law and propagate at a different angle of refraction than the ordinary rays.
  • the P-polarized light component and the S-polarized light component are focused at different positions in the depth direction of the wafer.
  • This branching of the focal point in the depth direction causes a plurality of unintentional focal points to be formed on the wafer, resulting in the formation of inappropriate cracks. This may reduce the quality of processing such as slicing.
  • the modulation pattern based on the optical axis profile so that the intensity of one focal point becomes large and the intensity of the other focal point becomes small, the plurality of focal points described above can be adjusted. It is possible to suppress deterioration in processing quality due to the formation of .
  • the control unit may cause the control unit to control, in the fifth process, the intensity of the light at the focal point on the side closer to the second surface of the two focal points increases, and
  • the modulation pattern may be adjusted so that the intensity of light at the focal point on the far side becomes smaller.
  • the intensity ratio of the two focal points can be changed by adjusting the modulation pattern, one of the focal points cannot be completely eliminated. For example, if you mainly use the light convergence point on the side far from the second surface and minimize the intensity of light at the light convergence point on the side close to the second surface, then is set at the processing target height, and there is a focal point near the second surface, although it is weak.
  • the device Since a device is provided on the second surface, it is conceivable that the device may be damaged due to the influence of the focal point on the side closer to the second surface.
  • the light convergence point on the side closer to the second surface is set at the processing target height, and the light is focused on the second surface side. Since no light spot exists, damage to the device on the second surface can be reduced. Note that even for a wafer in which no device is provided on the second surface, damage on the second surface can be reduced by providing the laser processing apparatus with the above configuration.
  • the control unit adjusts the modulation pattern using a slit pattern that blocks some polarized components of the laser beam. good. According to such a configuration, the intensity of light at any focal point can be easily reduced.
  • the control unit changes the spherical aberration conditions determined by the modulation pattern and performs the first processing, second processing, The third process and the fourth process are carried out, and in the fifth process, the maximum values of the brightness values of the laser beams indicated by the optical axis profiles acquired under each condition are compared with each other, and the optical axis having the maximum brightness value is
  • the modulation pattern may be adjusted to meet the spherical aberration conditions related to the profile. According to such a configuration, appropriate spherical aberration correction can be performed, for example, even for a wafer whose refractive index is unknown.
  • the control unit compares the optical axis profile acquired in the fourth process with comparison data that is a profile image for comparison, If the difference between the compared data is within a predetermined range, the optical axis profile is determined to be normal; if the difference is outside the predetermined range, the optical axis profile is determined to be abnormal, and the determination result is output.
  • a sixth process may be further executed. According to such a configuration, by setting a profile image when the laser processing device is normal as comparison data, it is possible to detect whether any abnormality occurs in the laser processing device based on the comparison between the optical axis profile and the comparison data. It can be easily determined whether the Then, by outputting the determination result, it becomes possible to adjust the laser processing apparatus in consideration of the determination result. As described above, according to the configuration described above, desired laser processing can be performed more appropriately.
  • the control unit controls the light source in the second process so that a laser beam with a lower output than the output during wafer processing is emitted. May be controlled. Thereby, an optical axis profile can be obtained without performing actual laser processing.
  • the optical axis profile may be three-dimensional data obtained by combining a plurality of two-dimensional captured images.
  • a laser processing method includes a condensing section that condenses laser light modulated by a spatial light modulator onto a wafer from a first surface side of a wafer having a first surface and a second surface. a first step of moving in the optical axis direction that is perpendicular to one surface; a second step of continuously emitting a laser beam while the first step is being executed; and the second step is executed. a third step of continuously acquiring a plurality of captured images by detecting the light reflected on the second surface in a state where the A fourth step of acquiring an optical axis profile which is a profile image of the laser beam along the optical axis direction.
  • the laser processing method may further include a fifth step of adjusting the modulation pattern of the spatial light modulator based on the optical axis profile acquired in the fourth step. good.
  • the wafer includes a birefringent material, and in the fifth step, based on the optical axis profile, a focal point for ordinary rays and a focal point for extraordinary rays are determined. Even if the modulation pattern is adjusted so that the intensity of light at one of the two identified focal points increases and the intensity of light at the other focal point decreases. good.
  • the intensity of the light at the focal point on the side closer to the second surface increases among the two focal points, and the intensity of the light on the side farther from the second surface increases.
  • the modulation pattern may be adjusted so that the intensity of light at the light spot is reduced.
  • the modulation pattern in the fifth step, may be adjusted by a slit pattern that blocks part of the polarized component of the laser beam.
  • the laser processing method described in any one of [E10] to [E15] above compares the optical axis profile acquired in the fourth step with comparison data that is a profile image for comparison, and a sixth step of determining that the optical axis profile is normal when the difference is within a predetermined range, determining that the optical axis profile is abnormal when the difference is outside the predetermined range, and outputting the determination result; may further include.
  • the optical axis profile may be three-dimensional data obtained by combining a plurality of two-dimensional captured images.
  • desired laser processing can be performed.
  • FIG. 1 is a configuration diagram of a laser processing apparatus according to an embodiment.
  • FIG. 2 is a cross-sectional view of a portion of the spatial light modulator shown in FIG.
  • FIG. 3(a) is a diagram illustrating continuous imaging along the Z direction
  • FIG. 3(b) is a diagram illustrating an optical axis profile obtained by combining captured images.
  • FIG. 4(a) is a cross-sectional view showing an optical axis profile represented by two-dimensional data
  • FIG. 4(b) is a diagram showing an optical axis profile represented by three-dimensional data.
  • FIG. 5 is a flowchart showing the optical axis profile acquisition process.
  • FIG. 1 is a configuration diagram of a laser processing apparatus according to an embodiment.
  • FIG. 2 is a cross-sectional view of a portion of the spatial light modulator shown in FIG.
  • FIG. 3(a) is a diagram illustrating continuous imaging along the Z direction
  • FIG. 3(b) is a diagram illustrating an optical
  • FIG. 6(a) is a diagram showing an optical axis profile of a wafer including a birefringent material
  • FIG. 6(b) is a diagram illustrating damage to a device due to light leakage.
  • FIGS. 7(a) and 7(b) are diagrams illustrating focal points depending on the birefringent material.
  • FIG. 8(a) is a diagram showing an optical axis profile of a wafer including a birefringent material
  • FIG. 8(b) is a diagram showing a modulation pattern in consideration of the optical axis profile shown in FIG. 8(a). It is a figure which shows the optical axis profile when adjusted.
  • FIG. 9(a) is an image of the focal point when no countermeasures are taken, and FIG.
  • FIG. 9(b) is an image of the focal point when the intensity of the front surface side focal point is increased.
  • c) is an image of the focal point when the intensity of the focal point on the back side is increased.
  • FIG. 10(a) is a diagram showing the intensity ratio in the case without a slit pattern
  • FIG. 10(b) is a diagram showing the intensity ratio in the case where the slit A is provided.
  • FIG. 11(a) is a diagram showing the intensity ratio when the slit B is provided
  • FIG. 11(b) is a diagram showing the intensity ratio when the slit C is provided.
  • FIG. 12 is a flowchart of modulation pattern adjustment processing.
  • FIG. 13 is a flowchart of error state identification processing of the laser processing apparatus.
  • FIG. 14(a) is a diagram showing the optical axis profile when a wafer with an unknown refractive index is processed with an inappropriate modulation pattern
  • FIG. 14(b) is a diagram considering the optical axis profile shown in FIG. 14(a).
  • FIG. 4 is a diagram showing an optical axis profile when a modulation pattern is adjusted by adjusting the modulation pattern. It is a figure explaining spherical aberration adjustment. It is a flowchart which shows spherical aberration adjustment processing.
  • the laser processing apparatus 1 includes a support section 2, a light source 3, an optical axis adjustment section 4, a spatial light modulator 5, a condensing section 6, a moving section 7, and a visible imaging section. It includes a section 8 (imaging section) and a control section 10. Note that the imaging unit may be an infrared camera.
  • the laser processing apparatus 1 is an apparatus that forms a modified region 12 on the wafer 11 by irradiating the wafer 11 with a laser beam L.
  • three mutually orthogonal directions will be referred to as an X direction, a Y direction, and a Z direction, respectively.
  • the X direction is a first horizontal direction
  • the Y direction is a second horizontal direction perpendicular to the first horizontal direction
  • the Z direction is a vertical direction.
  • the support section 2 supports the wafer 11 having a front surface 11a (first surface) and a back surface 11b (second surface).
  • the support section 2 supports the wafer 11 by adsorbing a film (not shown) attached to the wafer 11 so that the surface 11a of the wafer 11 is perpendicular to the Z direction.
  • the support portion 2 is movable along each of the X direction and the Y direction, and is rotatable about an axis parallel to the Z direction.
  • the light source 3 emits laser light L.
  • the light source 3 emits the laser beam L using a pulse oscillation method.
  • the laser beam L is transparent to the wafer 11.
  • the optical axis adjustment unit 4 adjusts the optical axis of the laser beam L emitted from the light source 3.
  • the optical axis adjustment unit 4 adjusts the optical axis of the laser beam L while changing the traveling direction of the laser beam L emitted from the light source 3 so as to follow the Z direction.
  • the optical axis adjustment section 4 is composed of, for example, a plurality of reflecting mirrors whose positions and angles can be adjusted.
  • the spatial light modulator 5 is placed inside the housing H.
  • the spatial light modulator 5 modulates the laser beam L emitted from the light source 3.
  • the laser beam L that has traveled downward along the Z direction from the optical axis adjustment unit 4 enters the housing H, and the laser beam L that has entered the housing H is directed in the Y direction by the mirror M1.
  • the laser beam L is reflected horizontally at an angle to the mirror M1 and enters the spatial light modulator 5.
  • the spatial light modulator 5 modulates the thus incident laser light L while horizontally reflecting it along the Y direction.
  • the spatial light modulator 5 of this embodiment is a reflective liquid crystal (LCOS) spatial light modulator (SLM). As shown in FIG. 2, the spatial light modulator 5 includes a drive circuit layer 52, a pixel electrode layer 53, a reflective film 54, an alignment film 55, a liquid crystal layer 56, an alignment film 57, and a transparent conductive film on a semiconductor substrate 51. 58 and a transparent substrate 59 are laminated in this order.
  • LCOS liquid crystal
  • SLM spatial light modulator
  • the semiconductor substrate 51 is, for example, a silicon substrate.
  • the drive circuit layer 52 constitutes an active matrix circuit on the semiconductor substrate 51.
  • the pixel electrode layer 53 includes a plurality of pixel electrodes 53a arranged in a matrix along the surface of the semiconductor substrate 51.
  • Each pixel electrode 53a is made of, for example, a metal material such as aluminum. A voltage is applied to each pixel electrode 53a by the drive circuit layer 52.
  • the reflective film 54 is, for example, a dielectric multilayer film.
  • the alignment film 55 is provided on the surface of the liquid crystal layer 56 on the reflective film 54 side, and the alignment film 57 is provided on the surface of the liquid crystal layer 56 on the opposite side to the reflective film 54 .
  • Each of the alignment films 55 and 57 is made of a polymeric material such as polyimide, and the contact surface of each of the alignment films 55 and 57 with the liquid crystal layer 56 is subjected to, for example, a rubbing treatment.
  • the alignment films 55 and 57 align liquid crystal molecules 56a included in the liquid crystal layer 56 in a certain direction.
  • the transparent conductive film 58 is provided on the surface of the transparent substrate 59 on the alignment film 57 side, and faces the pixel electrode layer 53 with the liquid crystal layer 56 and the like interposed therebetween.
  • the transparent substrate 59 is, for example, a glass substrate.
  • the transparent conductive film 58 is made of a light-transmitting and conductive material such as ITO, for example.
  • the transparent substrate 59 and the transparent conductive film 58 transmit the laser beam L.
  • the spatial light modulator 5 when a signal indicating a modulation pattern is input from the control unit 10 to the drive circuit layer 52, a voltage according to the signal is applied to each pixel electrode 53a, and each An electric field is formed between the pixel electrode 53a and the transparent conductive film 58.
  • the electric field is formed, in the liquid crystal layer 56, the arrangement direction of the liquid crystal molecules 216a changes for each region corresponding to each pixel electrode 53a, and the refractive index changes for each region corresponding to each pixel electrode 53a.
  • This state is a state in which a modulation pattern is displayed on the liquid crystal layer 56.
  • laser light L enters the liquid crystal layer 56 from the outside via the transparent substrate 59 and the transparent conductive film 58, is reflected by the reflective film 54, and is emitted from the liquid crystal layer 56.
  • the laser light L is modulated according to the modulation pattern displayed on the liquid crystal layer 56.
  • the modulation of the laser beam L for example, modulation of the intensity, amplitude, phase, polarization, etc. of the laser beam L
  • the modulation of the laser beam L can be performed.
  • the light condensing section 6 is attached to the bottom wall of the housing H.
  • the condensing section 6 condenses the laser beam L modulated by the spatial light modulator 5 onto the wafer 11 supported by the support section 2 .
  • the laser beam L reflected horizontally along the Y direction by the spatial light modulator 5 is reflected downward along the Z direction by the dichroic mirror M2, and the laser beam L reflected by the dichroic mirror M2 enters the light condensing section 6.
  • the condensing unit 6 condenses the laser beam L thus incident on the wafer 11 from the surface 11a (first surface) side along the Z direction.
  • the condensing section 6 is configured by a condensing lens unit 61 attached to the bottom wall of the housing H via a drive mechanism 62.
  • the condensing lens unit 61 has a function of condensing parallel light onto one point on the optical axis.
  • the drive mechanism 62 moves the condenser lens unit 61 along the Z direction by, for example, a drive force of a piezoelectric element.
  • an imaging optical system (not shown) is arranged between the spatial light modulator 5 and the light condensing section 6.
  • the imaging optical system constitutes a double-sided telecentric optical system in which the reflective surface of the spatial light modulator 5 and the entrance pupil plane of the condenser 6 are in an imaging relationship.
  • the image of the laser light L on the reflective surface of the spatial light modulator 5 (the image of the laser light L modulated by the spatial light modulator 5) is similarly transformed (formed) onto the entrance pupil plane of the condenser 6. image) to be done.
  • a pair of distance measuring sensors S1 and S2 are attached to the bottom wall of the housing H so as to be located on both sides of the condenser lens unit 61 in the X direction.
  • Each distance measurement sensor S1, S2 emits distance measurement light (for example, a laser beam) to the surface 11a of the wafer 11, and detects the distance measurement light reflected by the surface 11a. Obtain displacement data of 11a.
  • the moving unit 7 moves the light condensing unit 6 relative to the surface 11a of the wafer 11 in the optical axis direction (that is, the Z direction), which is a direction perpendicular to the surface 11a.
  • the moving unit 7 includes a moving mechanism (a driving source such as an actuator or a motor) that moves the light condensing unit 6 relative to the surface 11a of the wafer 11 by moving at least one of the housing H and the supporting unit 2. ).
  • the moving unit 7 moves the support unit 2 along each of the X direction and the Y direction, rotates the support unit 2 about an axis parallel to the Z direction, and rotates the support unit 2 along the Z direction. to move the housing H.
  • the visible imaging unit 8 is placed inside the housing H.
  • the visible imaging unit 8 emits visible light V and obtains an image of the wafer 11 using the visible light V.
  • the visible light V emitted from the visible imaging section 8 is irradiated onto the wafer 11 via the dichroic mirror M2 and the light condensing section 6, and the visible light V reflected by the wafer 11 is transmitted to the light condensing section 6 and the dichroic mirror M2. It is detected by the visible imaging unit 8 via the mirror M2. That is, the visible imaging section 8 acquires a captured image by detecting the light propagated through the wafer 11 via the light condensing section 6.
  • the control unit 10 controls the operation of each part of the laser processing device 1.
  • the control unit 10 includes a processing unit 101, a storage unit 102, and an interface unit 103.
  • the processing unit 101 is configured as a computer device including a processor, memory, storage, communication device, and the like.
  • a processor executes software (program) read into a memory or the like, and controls reading and writing of data in the memory and storage, and communication by a communication device.
  • the storage unit 102 is, for example, a hard disk or the like, and stores various data.
  • the interface unit 103 displays various data to the operator and receives input of various data from the operator. In this embodiment, the interface unit 103 constitutes a GUI (Graphical User Interface).
  • the modified region 12 is a region that differs in density, refractive index, mechanical strength, and other physical properties from the surrounding unmodified region.
  • Examples of the modified region 12 include a melt-treated region, a crack region, a dielectric breakdown region, and a refractive index change region.
  • the modified region 12 has a characteristic that cracks tend to extend from the modified region 12 to the incident side of the laser beam L and the opposite side thereof. Such characteristics of the modified region 12 are utilized for cutting the wafer 11, for example.
  • the operation of the laser processing apparatus 1 when forming the modified region 12 inside the wafer 11 along the line 15 for cutting the wafer 11 will be described.
  • the laser processing apparatus 1 rotates the support part 2 about an axis parallel to the Z direction as a center line so that the line 15 set on the wafer 11 is parallel to the X direction.
  • the laser processing device 1 moves the support part 2 along the X direction and the Y direction so that the condensing point C of the laser beam L is located on the line 15 when viewed from the Z direction. move it.
  • the laser processing apparatus 1 adjusts the focus point C of the laser beam L to be located on the surface 11a based on the image acquired by the visible imaging unit 8 (for example, the image of the surface 11a of the wafer 11). , move the housing H (that is, the light condensing section 6) along the Z direction. Next, the laser processing apparatus 1 moves the housing H (i.e., the light condensing part) along the Z direction so that the condensing point C of the laser beam L is located at a predetermined depth from the surface 11a, with this position as a reference. 6) Move.
  • the laser processing device 1 emits the laser beam L from the light source 3, and moves the support section 2 along the X direction so that the condensing point C of the laser beam L moves relatively along the line 15. move.
  • the laser processing apparatus 1 uses displacement data of the surface 11a acquired by the distance measurement sensor located on the front side (the front side in the relative movement direction of the laser beam L with respect to the wafer 11) among the pair of distance measurement sensors S1 and S2. Based on this, the drive mechanism 62 of the light focusing section 6 is operated so that the focusing point C of the laser beam L is located at a predetermined depth from the surface 11a.
  • a row of modified regions 12 are formed along line 15 and at a constant depth from surface 11a of wafer 11.
  • a plurality of modification spots 12s are formed in a line along the X direction.
  • One modification spot 12s is formed by irradiation with one pulse of laser light L.
  • a row of modified regions 12 is a collection of a plurality of modified spots 12s arranged in a row.
  • Adjacent modification spots 12s may be connected to each other or separated from each other depending on the pulse pitch of the laser beam L (the value obtained by dividing the relative moving speed of the focal point C with respect to the wafer 11 by the repetition frequency of the laser beam L). There is also. [Obtain optical axis profile]
  • the optical axis profile is the light reflected by the visible imaging section 8 on the back surface 11b of the wafer 11 in a state where the light condensing section 6 moves relative to the front surface 11a in the Z direction and the laser beam is emitted.
  • This data is obtained by combining a plurality of captured images that are detected and sequentially obtained.
  • the optical axis profile is a profile image of the laser beam along the Z direction, which is obtained by combining the plurality of captured images.
  • the irradiation status of the laser light along the optical axis direction (for example, the position and intensity of the focal point on the wafer 11) is specified. Thereby, it is possible to determine, for example, whether any abnormality has occurred in the laser processing apparatus 1, whether or not the modulation pattern set in the spatial light modulator 5 needs to be adjusted (details will be described later).
  • FIG. 3(a) is a diagram illustrating continuous imaging along the Z direction.
  • FIG. 3A from the left, imaging of cross section A, imaging of cross section B, imaging of cross section C, and imaging of cross section D are shown.
  • the light condensing section 6 is relatively moved in the Z direction so as to gradually approach the wafer 11 from left to right in the figure.
  • FIG. 3(a) when the position of the light condensing unit 6 moves by ⁇ Z, the path of the laser light reflected on the back surface 11b of the wafer 11 and imaged by the visible imaging unit 8 changes by combining the outgoing and returning paths. This results in a change of ⁇ Z ⁇ 2.
  • the light collecting section 6 is moved together with the visible imaging section 8, for example, by the moving section 7. That is, the focal point of the laser beam and the observation plane (camera imaging plane) of the visible imaging section 8 move together.
  • the condensing lens unit 61 and the like of the condensing section 6 may be moved by the drive mechanism 62.
  • the control unit 10 controls the moving unit 7 so that the condensing unit 6 moves relative to the surface 11a of the wafer 11 in the Z direction, and the first process is executed.
  • a second process of controlling the light source 3 so that the laser beam is continuously emitted in the state is executed.
  • the control unit 10 controls the light source 3 so that a laser beam with a lower output than the output when processing the wafer 11 is emitted.
  • the control unit 10 controls the visible imaging unit 8 so that the light reflected on the back surface 11b of the wafer 11 is detected and a plurality of captured images are continuously acquired while the second process is being executed.
  • a third process to control is executed.
  • the control unit 10 executes a fourth process of acquiring an optical axis profile, which is a profile image of the laser beam along the Z direction, by combining the plurality of captured images sequentially acquired in the third process. do.
  • FIG. 3(b) is a diagram showing an optical axis profile obtained by combining captured images.
  • captured images of each of cross sections A, B, C, and D are shown.
  • an optical axis is created that allows identification of the laser light irradiation status (for example, the position and intensity of the condensing point C).
  • a profile is obtained.
  • FIG. 4(a) is a cross-sectional view showing an optical axis profile represented by two-dimensional data
  • FIG. 4(b) is a diagram showing an optical axis profile represented by three-dimensional data.
  • the optical axis profile may be, for example, three-dimensional data obtained by combining a plurality of two-dimensional captured images (see FIG. 4(b)).
  • the three-dimensional data may be color-coded according to the intensity of the laser beam.
  • the optical axis profile may be two-dimensional data (see FIG. 4(a)) generated from the acquired three-dimensional data.
  • a graph showing the intensity of laser light in each region may be displayed alongside the two-dimensional data.
  • FIG. 5 is a flowchart showing the optical axis profile acquisition process performed by the laser processing apparatus 1.
  • a film to be attached to the wafer 11 is attracted by the support section 2 (step S1).
  • the moving unit 7 moves the condensing unit 6 under the control of the control unit 10, so that the wafer 11 is moved directly below the objective lens of the condensing unit 6 (step S2).
  • the moving unit 7 moves under the control of the control unit 10 so that the height in the Z direction is set at the reticle focus position (step S3).
  • the moving unit 7 moves under the control of the control unit 10 so that the height in the Z direction is lowered by the thickness of the wafer 11 (step S4).
  • a signal indicating a modulation pattern is input from the control unit 10 to the spatial light modulator 5.
  • a distortion correction pattern and a modulation pattern having a spherical aberration twice the wafer thickness are displayed (step S5).
  • step S6 all light sources other than the light source 3 in the laser processing apparatus 1 are turned off, and the light source 3 is controlled by the control unit 10 so that the laser beam is emitted (step S6).
  • Various settings such as the output of the laser beam are performed by the control unit 10 so that the laser beam can be reliably confirmed.
  • step S8 it is determined whether or not ablation has occurred on the surface of the wafer 11 (step S8). If ablation has occurred, the state is set such that ablation does not occur by adjusting the laser output or attenuator output (step S9). Then, the light sources other than the light source 3 in the laser processing apparatus 1 are turned on (step S10), and it is confirmed that the objective lens of the condenser 6 is located above the wafer 11 and at a position where no ablation is occurring (step S11). , the process is executed again from step S3.
  • step S8 fine adjustment in the Z direction is performed to the position where the laser beam is most focused (step S12), and the visible imaging unit that confirms the laser beam is A set value such as 8 is set to the optimum state (step S13).
  • control unit 10 controls the drive mechanism 62, which is an actuator for the objective lens of the condensing unit 6, or the moving unit 7, which is related to movement in the Z-axis direction, moves, the visible imaging unit 8 continuously An image is taken (step S14). Finally, the control unit 10 combines the plurality of captured images to obtain an optical axis profile near the focal point (step S15).
  • FIG. 6(a) is a diagram showing an optical axis profile of a wafer 11 that includes a birefringent material.
  • a laser beam enters a birefringent material, unlike silicon or glass, two focal points are generated: a focal point C1 for ordinary rays and a focal point C2 for extraordinary rays due to the difference in refractive index due to polarization. I will do it.
  • dicing is performed by irradiation with laser light, there is no major problem even if the focal point branches upward and downward in the dicing direction (Z direction).
  • processing accuracy may deteriorate due to the influence of the light condensing point being branched.
  • the lower light focusing point (here, the focusing point C2 of the extraordinary ray) is sufficiently spaced from the device (for example, the electrode 200) on the back surface 11b. In this case, damage to the electrode 200 due to light leakage is not a problem.
  • the lower light focusing point (here, the focusing point C2 of the extraordinary ray) is close to the device (for example, the electrode 200) on the back surface 11b. The problem is that the electrode 200 is damaged by the light passing through.
  • some kind of countermeasure is required to prevent deterioration of processing accuracy and damage to the device.
  • the focal point C1 of ordinary rays is higher than the focal point C2 of extraordinary rays. Whether it is branched (see FIG. 7(a)) or, conversely, branched below the focal point C2 of the extraordinary ray (see FIG. 7(b)) depends on the type of birefringent material. Specifically, for a positive birefringent material such as GaN or quartz, as shown in FIG. 7(a), the focal point C1 of the ordinary ray is branched above the focal point C2 of the extraordinary ray. Ru. On the other hand, for a negative birefringent material such as calcite or sapphire, as shown in FIG. 7(b), the focal point C1 of the ordinary ray is branched below the focal point C2 of the extraordinary ray.
  • the control unit 10 is configured to further execute a fifth process of adjusting the modulation pattern of the spatial light modulator 5 based on the optical axis profile acquired in the fourth process described above.
  • the control unit 10 specifies a focal point C1 for ordinary rays and a focal point C2 for extraordinary rays based on the optical axis profile, and selects one of the two identified focal points.
  • the modulation pattern is adjusted so that the intensity of light at one light point is increased and the intensity of light at the other focal point is decreased.
  • FIG. 8(a) is a diagram showing an optical axis profile of the wafer 11 including a birefringent material
  • FIG. 8(b) is a diagram showing a modulation pattern in consideration of the optical axis profile shown in FIG. 8(a). It is a figure which shows the optical axis profile when adjusted.
  • the control unit 10 specifies a focal point C1 of the vertically branched ordinary ray and a focal point C2 of the extraordinary ray from the optical axis profile. Then, the control unit 10 checks the optical axis profile, and as shown in FIG.
  • the intensity of the light at the focal point C2 due to the extraordinary ray increases, and the intensity of the light at the focal point C1 due to the ordinary ray increases. Adjust the modulation pattern so that the intensity of the light is reduced. This makes it possible to minimize the influence of the condensing point C1 where the intensity of light is reduced, and to suppress the adverse effects caused by the converging point branching upward and downward.
  • the wafer 11 is made of a positive birefringent material (Fig. 7(a)) or a negative birefringent material (see FIG. 7(b)).
  • FIG. 7(a) a case will be described in which a positive birefringent material (see FIG. 7(a)) is used.
  • Figure 9(a) is an image of the focal point when no measures are taken (the intensity ratio of the two focal points is not changed)
  • Figure 9(b) is an image of the focal point when the intensity of the front-side focal point is increased
  • FIG. 9C is an image of the focal point when the intensity of the back surface side focal point is increased.
  • the surface-side light convergence point is the light convergence point C1 of ordinary rays.
  • the back surface side focal point is the focal point C2 of the extraordinary ray.
  • the intensity ratio of the two condensing points C1 and C2 when the intensity ratio of the two condensing points C1 and C2 is not changed, the light passing through the condensing point C2 due to the extraordinary ray closer to the back surface 11b causes the back surface 11b to It is conceivable that the provided device (for example, the electrode 200) may be damaged.
  • the intensity of the focal point C1 due to the ordinary ray when the intensity of the focal point C1 due to the ordinary ray is increased and the intensity of the focal point C2 due to the extraordinary ray is decreased, the intensity is closer to the back surface 11b. Since the intensity of the condensing point C2 due to the extraordinary ray becomes smaller, the device (for example, the electrode 200) is less likely to be damaged than the example shown in FIG. For example, damage to the electrode 200) cannot be sufficiently reduced.
  • the convergence point C1 of the ordinary ray is set at the processing target height (see FIGS. 9(a) and 9(b)).
  • the focal point C2 of the extraordinary ray is set to the processing target height, the intensity of the focal point C2 of the extraordinary ray is increased, and the focal point C2 of the ordinary ray is set to the processing target height.
  • the intensity of C1 is reduced, the distance from the back surface 11b to the condensing point C2 becomes longer than in the example shown in FIG. 9(b).
  • the focal point C2 of the extraordinary ray is set at the processing target height, laser processing can be appropriately performed using the laser beam related to the focal point C2 of the extraordinary ray.
  • the control unit 10 performs the fifth process to control the light focusing point on the side closer to the back surface 11b (the focusing point caused by the extraordinary ray) of the two light focusing points.
  • the modulation pattern may be adjusted so that the intensity of the light C2) increases, and the intensity of the light at the focal point on the far side from the back surface 11b (the focal point C1 of ordinary rays) decreases.
  • the control unit 10 may adjust the modulation pattern using a slit pattern that blocks some polarized components of the laser beam.
  • a slit pattern is set as part of the modulation pattern displayed on the liquid crystal layer 56 of the spatial light modulator 5.
  • the laser beam L can be modulated (for example, the intensity, amplitude, phase, polarization, etc. of the laser beam L can be modulated) by appropriately setting the modulation pattern displayed on the liquid crystal layer 56.
  • the modulation pattern is a hologram pattern that imparts modulation, and includes a slit pattern.
  • FIG. 10(a) is a diagram showing the intensity ratio without a slit pattern
  • FIG. 10(b) is a diagram showing the intensity ratio with slit A
  • FIG. 11(a) is a diagram showing the intensity ratio with slit B
  • 11(b) is a diagram showing the intensity ratio when a slit C is provided.
  • FIG. 10(a) to 11(b) the upper row shows the modulation pattern (including the slit pattern) displayed on the liquid crystal layer 56 of the spatial light modulator 5, and the lower row shows the optical axis. Two-dimensional data of the profile is shown.
  • the slit patterns shown in FIGS. 10(b), 11(a), and 11(b) are each provided with fan-shaped slits. Below, the concept of bringing the focal point closer to one point regarding birefringent materials and the reason for using fan-shaped slits will be explained.
  • the P-polarized light component and the S-polarized light component of the laser light have different refractive indices.
  • the laser beam is divided into ordinary rays and extraordinary rays, but the extraordinary rays do not follow Snell's law and propagate at a different angle of refraction from the ordinary rays. Therefore, the P-polarized light component and the S-polarized light component are focused at different positions in the depth direction of the wafer (there are two focused points).
  • the radial polarized light enters the wafer as P-polarized light.
  • the azimuthal polarized light enters the wafer as S-polarized light. Therefore, by converting linearly polarized light into either radial or azimuth polarized light, the polarization components of the laser beam can be unified into either P-polarized light or S-polarized light, and the focal point can be appropriately focused on one point. You can get close.
  • the azimuthal polarization component When using a linear slit, the azimuthal polarization component will remain unless the slit is narrowed, but if the slit is narrowed, the effective pattern area will become narrower.
  • processing can be performed using areas with strong radial components while maintaining an effective pattern area.
  • the area of the slit pattern SP3 is larger than the area of the slit pattern SP2.
  • the area of slit pattern SP4 is larger than the area of .
  • the difference in intensity between the focal point C2 due to the extraordinary ray and the focal point C1 due to the ordinary ray is the smallest for the case without a slit pattern (FIG. 10(a)), and the difference in intensity between the focal point C2 due to the extraordinary ray and the focal point C1 due to the ordinary ray is the smallest for the modulation pattern MP2 including the slit pattern SP2 (FIG. 10(a)).
  • b)) becomes the next smallest
  • the modulation pattern MP3 (FIG. 11(a)) including the slit pattern SP3 becomes the next smallest
  • the modulation pattern MP4 (FIG. 11(b)) including the slit pattern SP4 becomes the largest.
  • the slit pattern area increases, the difference in intensity between the two focal points increases, but since the effective pattern area narrows, it is necessary to increase the output of the laser beam. In addition, it is more likely to be affected when combined with other patterns such as branches. For example, in the modulation pattern MP4 shown in FIG. 11(b), the laser beam is cut too much by the slit pattern SP4, resulting in astigmatism and other adverse effects on light focusing performance.
  • FIG. 12 is a flowchart of modulation pattern adjustment processing.
  • the modulation pattern adjustment process first, an optical axis profile near the focal point is acquired (step S101).
  • step S102 the distance from the focal point C1 of the ordinary ray to the focal point C2 of the extraordinary ray is measured. This distance is necessary when setting the focal point C2 of the extraordinary ray to the processing target height when using the extraordinary ray in laser processing, assuming that the processing conditions are created using the refractive index of the ordinary ray. This is information that will become
  • step S103 it is determined whether or not to use an extraordinary ray in laser processing. If it is determined in step S103 that an extraordinary ray is to be used, the modulation pattern is adjusted so that the intensity of the focal point C2 due to the extraordinary ray is increased (step S104).
  • step S105 After adjusting the modulation pattern, the optical axis profile near the focal point is acquired again (step S105). Then, the intensities of the focal point C2 due to the extraordinary ray and the focal point C1 due to the ordinary ray are compared (step S106), and it is determined whether they are within the normal range (step S107). If it is not within the normal range, the process of step S104 is performed again. If it is within the normal range, the distance acquired in step S102 is reflected in the machining recipe, and the focal point C2 of the abnormal ray is set to the target machining height (step S108).
  • step S103 determines whether the extraordinary ray is not used (ordinary ray is used). If it is determined in step S103 that the extraordinary ray is not used (ordinary ray is used), the modulation pattern is adjusted so that the intensity of the focal point C1 by the ordinary ray is increased (step S109). .
  • the optical axis profile near the focal point is acquired again (step S110). Then, the intensities of the focal point C1 of the ordinary ray and the focal point C2 of the extraordinary ray are compared (step S111), and it is determined whether they are within the normal range (step S112). If it is not within the normal range, the process of step S109 is executed again, and if it is within the normal range, the process ends. [Identification of error status of laser processing equipment]
  • the control unit 10 compares the optical axis profile acquired in the fourth process with comparison data that is a profile image for comparison, and determines that the optical axis profile is normal if the difference between the compared data is within a predetermined range. If the difference is outside a predetermined range, the optical axis profile is determined to be abnormal, and a sixth process may be further executed in which the determination result is output.
  • the fact that the optical axis profile is abnormal means that the laser processing apparatus 1 is in some kind of error state.
  • the control unit 10 may use, for example, an optical axis profile acquired in the past as a profile image for comparison. Alternatively, the control unit 10 may use, for example, data created based on simulation as the profile image for comparison.
  • the control unit 10 determines that there is a severe error and outputs the determination result.
  • Severe errors include, for example, abnormalities in laser processing equipment and measurement errors (wafer errors).
  • the control unit 10 determines that there is an abnormality in the spatial light modulator 5 (for example, spherical aberration, error in distortion correction, etc.). If the adjustment of the laser beam is incorrect, the laser beam is readjusted.
  • FIG. 13 is a flowchart of the error state identification process of the laser processing apparatus 1.
  • an optical axis profile near the focal point is acquired (step S201).
  • the acquired optical axis profile is compared with comparison data that is a profile image for comparison (for example, an optical axis profile acquired in the past) (step S202), and the difference between the compared data is determined to be normal. It is determined whether it is within the range (step S203). The difference between the data is, for example, the difference in the position of the focal point, the intensity, etc. If it is determined in step S203 that it is normal, the control unit 10 displays that it is normal (step S204).
  • step S203 If it is determined in step S203 that it is not normal, the control unit 10 displays an error message (step S205). Then, the control unit 10 confirms the error details and determines whether or not there is no focal point (step S206). If it is determined in step S206 that the focal point does not exist, it is determined that a serious error has occurred (step S207).
  • a severe error is, for example, an abnormality in a laser processing device or a measurement error (wafer error, etc.).
  • step S208 determines whether the adjustment of the laser beam is correct. If the adjustment of the laser beam is correct, it is determined that there is an abnormality in the spatial light modulator 5 (for example, spherical aberration, error in distortion correction, etc.) (step S209); if the adjustment of the laser beam is incorrect, the laser beam is Readjustment is performed (step S210).
  • an abnormality in the spatial light modulator 5 for example, spherical aberration, error in distortion correction, etc.
  • the control unit 10 performs the above-described first processing, second processing, third processing, and fourth processing under each condition while changing the spherical aberration conditions determined by the modulation pattern, and in the fifth processing,
  • the maximum brightness values of the laser beams indicated by the optical axis profiles obtained under each condition are compared, and the modulation pattern is adjusted to meet the spherical aberration conditions associated with the optical axis profile with the maximum brightness value. It's okay.
  • a wafer 11 whose refractive index is unknown may be processed with an inappropriate modulation pattern.
  • FIG. 14(a) by acquiring the optical axis profile, it is determined that the position of the focal point is shifted, and it is not appropriate for the wafer 11 whose refractive index is unknown. You can notice that a modulation pattern has been set. Then, while checking the optical axis profile as shown in FIG. 14(a), the control unit 10 performs spherical aberration correction so that the optical axis profile as shown in FIG. 14(b) is acquired. This makes it possible to set an appropriate modulation pattern for laser processing of the wafer 11 whose refractive index is unknown.
  • control unit 10 corrects the reference spherical aberration while changing the correction value, selects the correction value that maximizes the brightness value at the focal point, and adjusts the spherical aberration after correction using the correction value. Adjust the modulation pattern to meet the conditions.
  • the reference spherical aberration may be, for example, twice the thickness of the wafer 11.
  • FIG. 16 is a flowchart showing the spherical aberration adjustment process.
  • a spherical aberration of twice the wafer thickness which is considered to be optimal, is determined as a reference (step S301).
  • the control unit 10 sets a modulation pattern to satisfy the reference spherical aberration condition (step S302), and obtains an optical axis profile near the focal point (step S303).
  • control unit 10 sets a modulation pattern such that the spherical aberration is smaller by an arbitrary value than the reference spherical aberration (step S304), and obtains an optical axis profile near the focal point (step S304). S305).
  • control unit 10 sets a modulation pattern such that the spherical aberration is larger than the reference spherical aberration by an arbitrary value (step S306), and obtains an optical axis profile near the focal point (step S306). S307).
  • control unit 10 determines whether the maximum brightness value is larger if the spherical aberration is set to an arbitrary value smaller than the reference spherical aberration, based on the acquired optical axis profile (step S308). If it is determined in step S308 that setting the spherical aberration smaller by an arbitrary value will result in a larger maximum luminance value, the control unit 10 sets the spherical aberration smaller by an arbitrary value as a new standard (step S309), and again Processing after step S302 is performed.
  • step S308 if it is determined in step S308 that the maximum brightness value is not larger when the spherical aberration is set to a smaller arbitrary value (that is, the maximum brightness value is larger when set to the standard), the control unit 10 It is determined whether or not the maximum brightness value of the spherical aberration is the maximum (step S310). In step S310, if it is determined that the reference spherical aberration has the maximum maximum brightness value, the control unit 10 reflects a value of 1/2 of the reference spherical aberration in the processing recipe (step S311 ).
  • step S310 determines whether the maximum brightness value of the reference spherical aberration is not the maximum (that is, the spherical aberration that is arbitrarily large has the maximum maximum brightness value)
  • the control unit 10 A spherical aberration with an arbitrarily large value is set as a new reference (step S312), and the processes from step S302 onwards are performed again.
  • the laser processing apparatus 1 includes a support section 2 that supports a wafer 11 having a front surface 11a and a back surface 11b, a light source 3 that emits laser light, and a spatial light modulator 5 that modulates the laser light emitted from the light source 3.
  • a focusing section 6 focuses the laser beam modulated by the spatial light modulator 5 onto the wafer 11 from the surface 11a side of the wafer 11, and the focusing section 6 is aligned in the optical axis direction, which is a direction perpendicular to the surface 11a.
  • a laser beam is irradiated while moving the light condensing unit 6 in the optical axis direction, and the light reflected on the back surface 11b of the wafer 11 is detected and a plurality of captured images are continuously generated. is obtained.
  • a plurality of captured images are combined to obtain an optical axis profile that is a profile image of the laser beam along the optical axis direction. In this way, while moving the focal point of the laser beam in the optical axis direction (in the depth direction of the wafer 11), the reflected light from the back surface 11b of the wafer 11 is detected, and the optical axis profile is acquired.
  • the control unit 10 may further execute a fifth process of adjusting the modulation pattern of the spatial light modulator 5 based on the optical axis profile acquired in the fourth process.
  • the modulation pattern can be optimized in consideration of the optical axis profile, and desired laser processing can be performed more appropriately.
  • the wafer 11 is configured to include a birefringent material, and in the fifth process, the control unit 10 identifies a focal point for ordinary rays and a focal point for extraordinary rays based on the optical axis profile.
  • the modulation pattern may be adjusted so that the intensity of light at one of the two identified focal points is increased and the intensity of light at the other focal point is decreased.
  • the refractive indexes of the P-polarized light component and the S-polarized light component of the incident light are different from each other.
  • these incident lights are divided into ordinary rays and extraordinary rays, but the extraordinary rays do not follow Snell's law and propagate at a different angle of refraction than the ordinary rays.
  • the P-polarized light component and the S-polarized light component are focused at different positions in the depth direction of the wafer 11.
  • a plurality of focal points are unintentionally formed on the wafer 11, resulting in formation of inappropriate cracks. This may reduce the quality of processing such as slicing.
  • the modulation pattern based on the optical axis profile so that the intensity of one focal point becomes large and the intensity of the other focal point becomes small, the plurality of focal points described above can be adjusted. It is possible to suppress deterioration in processing quality due to the formation of .
  • the control unit 10 increases the intensity of the light at the focal point closer to the back surface 11b among the two focal points, and decreases the intensity of the light at the focal point farther from the back surface 11b.
  • the modulation pattern may be adjusted so that Although the intensity ratio of the two focal points can be changed by adjusting the modulation pattern, one of the focal points cannot be completely eliminated. For example, if you mainly use the focal point on the side far from the back surface 11b and make the focal point on the side close to the back surface 11b as small as possible, the focal point on the side far from the back surface 11b is set to the processing target height. Therefore, there is a focal point near the back surface 11b, although it is weak.
  • the focal point on the side closer to the back surface 11b is mainly used, the focal point on the side closer to the back surface 11b is set at the processing target height, and the focal point on the side closer to the back surface 11b is set to the processing target height. Since it does not exist, damage to the device on the back surface 11b can be reduced.
  • control unit may adjust the modulation pattern using a slit pattern that blocks some polarized components of the laser beam. According to such a configuration, the intensity of any one of the focal points can be easily weakened.
  • the control unit 10 performs the first processing, the second processing, the third processing, and the fourth processing under each condition while changing the spherical aberration conditions determined by the modulation pattern, and in the fifth processing, each condition is changed.
  • the maximum brightness values of the laser beams indicated by the optical axis profiles obtained below are compared with each other, and the modulation pattern is adjusted to meet the spherical aberration conditions related to the optical axis profile with the maximum brightness value. good. According to such a configuration, appropriate spherical aberration correction can be performed, for example, even for the wafer 11 whose refractive index is unknown.
  • the control unit 10 compares the optical axis profile acquired in the fourth process with comparison data that is a profile image for comparison, and determines that the optical axis profile is normal if the difference between the compared data is within a predetermined range. If the difference is outside a predetermined range, the optical axis profile is determined to be abnormal, and a sixth process may be further executed in which the determination result is output.
  • a sixth process may be further executed in which the determination result is output.
  • control unit 10 may control the light source 3 so that a laser beam with a lower output than the output when processing the wafer 11 is emitted. Thereby, an optical axis profile can be obtained without performing actual laser processing.
  • the optical axis profile may be three-dimensional data obtained by combining a plurality of two-dimensional captured images.
  • SYMBOLS 1 Laser processing device, 2... Support part, 3... Light source, 5... Spatial light modulator, 6... Condensing part, 7... Moving part, 8... Visible imaging part (imaging part), 10... Control part, 11... Wafer, 11a...front surface (first surface), 11b...back surface (second surface).

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Abstract

Le dispositif de traitement laser selon l'invention comprend : une unité de support qui supporte une tranche; une source de lumière; un modulateur optique spatial; une unité de collecte de lumière; une unité de déplacement qui déplace l'unité de collecte de lumière dans une direction d'axe optique perpendiculaire à sa surface, par rapport à la surface; une unité de capture d'image visible qui acquiert une image capturée par détection d'une lumière qui s'est propagée dans la tranche à travers l'unité de collecte de lumière; et une unité de commande. L'unité de commande est configurée pour effectuer : un premier processus pour commander l'unité de déplacement; un deuxième processus pour commander une source de lumière 3 de façon à émettre une lumière laser en continu; un troisième processus pour commander l'unité de capture d'image visible de telle sorte que la lumière réfléchie sur la surface arrière de la tranche peut être détectée pour acquérir une pluralité d'images capturées en continu; et un quatrième processus pour composer la pluralité d'images capturées pour ainsi acquérir un profil d'axe optique qui est une image de profil de la lumière laser le long de la direction d'axe optique.
PCT/JP2023/015987 2022-08-12 2023-04-21 Dispositif de traitement laser et procédé de traitement laser WO2024034193A1 (fr)

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JP2019147191A (ja) * 2019-05-21 2019-09-05 株式会社東京精密 レーザー加工領域の確認装置及び確認方法
JP2021086902A (ja) * 2019-11-27 2021-06-03 浜松ホトニクス株式会社 レーザ加工装置及びレーザ加工方法
JP2021090990A (ja) * 2019-12-11 2021-06-17 株式会社ディスコ レーザービームのスポット形状の補正方法
JP2022018505A (ja) * 2020-07-15 2022-01-27 浜松ホトニクス株式会社 レーザ加工方法、及び、半導体部材の製造方法
JP2022036013A (ja) * 2020-08-21 2022-03-04 浜松ホトニクス株式会社 レーザ加工装置及びレーザ加工方法
JP2022115567A (ja) * 2021-01-28 2022-08-09 浜松ホトニクス株式会社 観察装置及び観察方法
JP2022115589A (ja) * 2021-01-28 2022-08-09 浜松ホトニクス株式会社 レーザ加工装置及びレーザ加工方法

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2019147191A (ja) * 2019-05-21 2019-09-05 株式会社東京精密 レーザー加工領域の確認装置及び確認方法
JP2021086902A (ja) * 2019-11-27 2021-06-03 浜松ホトニクス株式会社 レーザ加工装置及びレーザ加工方法
JP2021090990A (ja) * 2019-12-11 2021-06-17 株式会社ディスコ レーザービームのスポット形状の補正方法
JP2022018505A (ja) * 2020-07-15 2022-01-27 浜松ホトニクス株式会社 レーザ加工方法、及び、半導体部材の製造方法
JP2022036013A (ja) * 2020-08-21 2022-03-04 浜松ホトニクス株式会社 レーザ加工装置及びレーザ加工方法
JP2022115567A (ja) * 2021-01-28 2022-08-09 浜松ホトニクス株式会社 観察装置及び観察方法
JP2022115589A (ja) * 2021-01-28 2022-08-09 浜松ホトニクス株式会社 レーザ加工装置及びレーザ加工方法

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