Processing method and processing device

Abstract

In a first step, a first laser is scanned along a processing target region while the processing target region is irradiated with the first laser, the first laser forming a spot having a length in the width direction of the processing target region on a street shorter than the width of the processing target region. In the first step, the first laser is irradiated so that a plurality of scanning trajectories of the spot of the first laser are formed in the width direction of the processing target region. In a second step following the first step, a second laser is scanned along the processing target region while the processing target region is irradiated with the second laser, the second laser forming a spot having a length in the width direction of the processing target region corresponding to the width of the processing target region.

Description

Processing method and processing device

[0001] The disclosed technique relates to a processing method and processing apparatus for forming grooves in streets that separate a plurality of devices provided on a semiconductor wafer.

[0002] The following techniques are known as techniques for forming grooves in streets that separate multiple devices provided on a semiconductor wafer. For example, Japanese Patent Application Laid-Open No. 2016-68149 describes a laser processing device equipped with an optical axis swinging means that swings the optical axis of a pulsed laser beam oscillated from a pulsed laser beam oscillator and guides it to a condenser.

[0003] JP 2014-223677 A describes a method characterized in that a laser scribe head creates a two-dimensional array of laser beam spots.

[0004] Japanese Patent Application Laid-Open No. 2022-107953 describes a laser processing device that includes a spot shaping unit that shapes the spot shape of a pulsed laser beam emitted by an oscillator so that it is long in the Y-axis direction and short in the X-axis direction, and a polygon mirror that disperses the spot shaped by the spot shaping unit in the X-axis direction.

[0005] Low-k films used as insulating films in semiconductor devices have low mechanical strength, and there is a risk of film peeling when using conventional blade dicing. For this reason, prior to blade dicing, laser grooving is performed using a pulsed laser to remove the wiring layer, including the low-k film, along the streets that separate multiple devices on the semiconductor wafer. Laser grooving poses problems such as heat damage to the devices and the generation of debris.

[0006] To address the heat issue, it is conceivable to use an ultrashort pulse laser with a pulse width on the order of pico to femto. However, laser heads capable of outputting ultrashort pulse lasers are generally expensive, and introducing them requires significant costs.

[0007] Another possible solution is to scan a low-energy laser multiple times along the street. However, if a metal-containing structure is present on the street, the low-energy laser may not be able to remove the structure even by scanning multiple times.

[0008] The disclosed technology has been made in consideration of the above points, and aims to realize processing to form grooves along streets that separate multiple devices formed on a semiconductor wafer using a laser with lower energy.

[0009] A processing method according to the disclosed technology is a processing method for forming grooves along streets that partition multiple devices provided on a semiconductor wafer. This processing method includes a first step of irradiating a processing target area with a first laser that forms a spot on the street whose length in the width direction of the processing target area is shorter than the width of the processing target area while scanning the processing target area, and a second step, after the first step, of irradiating a processing target area with a second laser that forms a spot whose length in the width direction of the processing target area is a length corresponding to the width of the processing target area while scanning the processing target area. In the first step, the first laser is irradiated so that multiple scanning trajectories of the first laser spot are aligned in the width direction of the processing target area.

[0010] In the first step, the process of irradiating the area to be processed with the first laser, which forms a single spot, and scanning along the area to be processed may be carried out multiple times while changing the irradiation position of the first laser in the width direction of the area to be processed.

[0011] The first laser may form a plurality of spots arranged at different positions in the width direction of the processing target area.

[0012] The first laser may be applied so that the direction in which the plurality of spots are arranged is perpendicular to the direction in which the processing target area extends. The first laser may be applied so that the direction in which the plurality of spots are arranged is inclined with respect to the direction in which the processing target area extends.

[0013] The first laser may form a plurality of spots arranged at different positions in a width direction of the processing target area and a plurality of spots arranged at different positions in a scanning direction of the first laser.

[0014] In the first step, projections and recesses may be formed in a film or structure present in the processing target area by irradiating the first laser, or cracks or voids may be formed in the film or structure.

[0015] In the first step, the film or structure present in the processing target area may be divided or fractured by irradiation with the first laser, or irregularities may be formed on the surface of the film or structure.

[0016] In the second step, a film or structure present in the processing target region may be removed by irradiating the second laser.

[0017] A processing apparatus according to the disclosed technology is a processing apparatus for forming grooves along streets that partition multiple devices on a semiconductor wafer. This processing apparatus includes: a first laser irradiation means that irradiates a processing target area on the street with a first laser that forms a spot whose length in the width direction of the processing target area on the street is shorter than the width of the processing target area while scanning the processing target area; and a second laser irradiation means that irradiates a processing target area with a second laser that forms a spot whose length in the width direction of the processing target area corresponds to the width of the processing target area while scanning the processing target area. The first laser irradiation means irradiates the first laser so that multiple scanning trajectories of the first laser spot are aligned in the width direction of the processing target area.

[0018] According to the disclosed technology, it is possible to perform processing to form grooves along streets that separate multiple devices provided on a semiconductor wafer using a laser with lower energy.

[0019] 1 is a plan view showing an example of a processing mode in a first step according to an embodiment of the disclosed technology. FIG. 1 is a plan view showing an example of a processing mode in a first step according to an embodiment of the disclosed technology. FIG. 2 is a plan view showing an example of a processing mode in a first step according to an embodiment of the disclosed technology. FIG. 3 is a cross-sectional view showing an example of a state of a processing target area after completion of a first step according to an embodiment of the disclosed technology. FIG. 4 is a cross-sectional view showing an example of a state of a processing target area after completion of a first step according to an embodiment of the disclosed technology. FIG. 5 is a cross-sectional view showing an example of a state of a processing target area after completion of a first step according to an embodiment of the disclosed technology. FIG. 6 is a diagram showing an example of a configuration of a first laser optical system used in a first step according to an embodiment of the disclosed technology. FIG. 7 is a diagram showing another example of a configuration of a first laser optical system used in a first step according to an embodiment of the disclosed technology. FIG. 8 is a plan view showing an example of a processing mode in a second step according to an embodiment of the disclosed technology. FIG. 9 is a cross-sectional view showing an example of a state of a processing target area after completion of a second step according to an embodiment of the disclosed technology. FIG. 10 is a diagram showing an example of a configuration of a second laser optical system used in a second step according to an embodiment of the disclosed technology. FIG. 11 is an image showing a state of a street when a groove is formed along the street by a processing method according to a comparative example. FIG. 1 is an image showing the state of a street when a groove is formed along the street by a processing method according to the disclosed technology. FIG. 2 is a plan view showing an example of a processing mode in a first step according to another embodiment of the disclosed technology. FIG. 3 is a plan view showing an example of a processing mode in a first step according to another embodiment of the disclosed technology. FIG. 4 is a plan view showing an example of another processing mode in a first step according to another embodiment of the disclosed technology. FIG. 5 is a plan view showing an example of another processing mode in a first step according to another embodiment of the disclosed technology. FIG. 6 is a diagram showing an example of a configuration of a first laser optical system used in a first step according to another embodiment of the disclosed technology. FIG. 7 is a diagram showing another example of a configuration of a first laser optical system used in a first step according to another embodiment of the disclosed technology.1 is a diagram showing an example of a method for adjusting the rotation angle of a diffractive optical element according to an embodiment of the disclosed technique; FIG. 2 is a plan view showing an example of a processing mode in a first step according to another embodiment of the disclosed technique; and FIG. 3 is a diagram showing an example of a configuration of a first laser optical system used in the first step according to another embodiment of the disclosed technique.

[0020] Hereinafter, embodiments of the disclosed technology will be described with reference to the drawings. In each drawing, substantially the same or equivalent components or parts are denoted by the same reference numerals.

[0021] A processing method according to an embodiment of the disclosed technology is a method for forming grooves in streets that separate multiple devices on a semiconductor wafer, and relates to laser grooving, which is applied in the manufacturing process of semiconductor devices. Laser grooving is a processing method that exposes the silicon substrate of the semiconductor wafer by forming grooves along the streets while removing films or structures on the streets with a pulsed laser. Laser grooving is performed prior to blade dicing for cutting semiconductor chips from the semiconductor wafer. The film to be removed in laser grooving may be, for example, an insulating film such as a low-k film present on the streets. The structure to be removed in laser grooving may be, for example, a metal such as a TEG (Test Element Group) electrode present on the streets. In laser grooving, a processing target area is set on the street. The processing target area is an area contained within the street and is an area to be processed by laser irradiation. The processing target area extends along the street. In the following, the direction in which the street extends (i.e., the direction in which the processing target area extends) is referred to as the X direction, the width direction of the street (i.e., the width direction of the processing target area) is referred to as the Y direction, and the depth direction of the semiconductor wafer is referred to as the Z direction, and these directions are clearly indicated in each drawing.

[0022] [First Embodiment] A processing method according to an embodiment of the disclosed technology includes a first step and a second step. FIG. 1 is a plan view showing an example of a processing mode in the first step. In the first step, a first laser is irradiated onto a processing target area 10 set on a street 2 and scanned along the processing target area 10. The length d1 of the first laser spot 11 in the width direction (Y direction) of the processing target area 10 is shorter than the width W of the processing target area 10. The shape of the first laser spot 11 is not particularly limited, but may be, for example, circular. Alternatively, as shown in FIGS. 2 and 3, the shape of the first laser spot 11 may be rectangular or elliptical with the longitudinal direction of the spot oriented in the extension direction (X direction) of the processing target area 10.

[0023] In the first step, the first laser is irradiated so that multiple scanning trajectories 12 of the spot 11 of the first laser are aligned in the width direction (Y direction) of the processing target area 10. For example, as shown in Fig. 1 , the process of scanning the processing target area 10 along the processing target area 10 while irradiating the processing target area 10 with the first laser forming a single spot 11 may be performed multiple times while changing the irradiation position of the first laser in the width direction (Y direction) of the processing target area 10.

[0024] 4A, 4B, and 4C are cross-sectional views (YZ cross-sectional views) showing an example of the state of the processing target area 10 after the first step is completed. A semiconductor wafer to which the processing method according to this embodiment is applied has a substrate 100 made of a semiconductor such as silicon, and an insulating film 101 provided on the surface of the substrate 100. The insulating film 101 extends not only in the semiconductor device formation area but also in the processing target area 10. The insulating film 101 is made of, for example, SiO ２ and may be a so-called low-k film. The insulating film 101 present in the processing target region 10 is the target to be removed in the laser grooving according to this embodiment. Note that structures such as TEG electrodes may be present in the processing target region 10, and such structures are also the target to be removed.

[0025] 4A , in the first step, the first laser may be irradiated to form irregularities 102 on the surface of the insulating film 101 present in the processing target region 10. By irradiating the processing target region 10 with the first laser so that multiple scanning trajectories of the first laser spot 11 are aligned in the width direction (Y direction) of the processing target region 10, the irregularities 102 can be formed over a wide range in the width direction of the processing target region 10.

[0026] 4B , in the first step, cracks 103 may be generated in the insulating film 101 present in the processing target region 10 by irradiating the insulating film 101 with a first laser. The cracks 103 extend from the surface of the insulating film 101 in the depth direction (Z direction) of the semiconductor wafer. By irradiating the processing target region 10 with the first laser so that multiple scanning trajectories of the first laser spot 11 are aligned in the width direction (Y direction) of the processing target region 10, multiple cracks 103 aligned in the width direction of the processing target region 10 can be generated.

[0027] 4C , in the first step, voids 104 may be formed in the insulating film 101 present in the processing target region 10 by irradiating the first laser. The voids 104 extend from the surface of the insulating film 101 in the depth direction (Z direction) of the semiconductor wafer. By irradiating the processing target region 10 with the first laser so that multiple scanning trajectories of the first laser spot 11 are aligned in the width direction (Y direction) of the processing target region 10, multiple voids 104 aligned in the width direction of the processing target region 10 can be formed.

[0028] At the completion of the first step, one of the irregularities 102, the cracks 103, and the voids 104 may be formed in the insulating film 101 present in the processing target area 10, or two or more of the irregularities 102, the cracks 103, and the voids 104 may be present together. Furthermore, in the first step, the insulating film 101 present in the processing target area 10 may be divided or fractured by irradiation with the first laser. If a structure such as a TEG electrode is present in the processing target area 10, in the first step, irregularities may be formed on the surface of the structure, cracks may be generated in the structure, or voids may be formed in the structure by irradiation with the first laser. In addition, in the first step, the structure present in the processing target area 10 may be divided or fractured by irradiation with the first laser.

[0029] FIG. 5 is a diagram showing an example of the configuration of the first laser optical system 30 used in the first step. The first laser optical system 30 includes a laser oscillator 31 and a lens 32. The semiconductor wafer 1 to be processed is held on a stage 50. The laser oscillator 31 outputs a first laser L1. The first laser L1 may be a UV pulse laser. The first laser L1 output from the laser oscillator 31 is irradiated onto the surface of the semiconductor wafer 1 via a lens 32. The focus of the lens 32 is adjusted to the surface of the semiconductor wafer 1, and a spot of the first laser L1 is formed on the surface of the semiconductor wafer 1. By moving the stage 50 in the X and Y directions, the irradiation position of the first laser L1 can be moved along the processing target region 10. To avoid thermal damage to the device and the generation of debris, it is preferable to control the output of the laser oscillator 31 so that the energy per spot of the first laser L1 is 10 μJ or less.

[0030] 6 and 7 are diagrams showing other examples of the configuration of the first laser optical system 30 used in the first step. As shown in Fig. 6, the first laser optical system 30 may include a beam shaper 33 for shaping the spot of the first laser L1 into a desired shape. Furthermore, as shown in Fig. 7, the first laser optical system 30 may include a 4f optical system 34 for removing noise. Furthermore, the first laser optical system 30 may include a beam expander (not shown) for adjusting the beam diameter to an appropriate size and an attenuator (not shown) for adjusting the laser output.

[0031] FIG. 8 is a plan view showing an example of the processing mode in the second step. The second step is performed after the first step. In the second step, the second laser is irradiated onto the processing target area 10 and scanned along the processing target area 10. The length d2 of the second laser spot 21 in the width direction (Y direction) of the processing target area 10 is the same as or slightly shorter than the width W of the processing target area 10. The length d2 of the second laser spot 21 in the width direction (Y direction) of the processing target area 10 is preferably 80% or more and less than 100% of the width W of the processing target area 10. The length d2 of the second laser spot 21 in the width direction (Y direction) of the processing target area 10 is longer than the length d1 of the first laser spot 11 in the width direction (Y direction) of the processing target area 10. The shape of the second laser spot 21 may be, for example, rectangular as illustrated in FIG. 8, or may be elliptical, oval, or circular.

[0032] FIG. 9 is a cross-sectional view (Y-Z cross-sectional view) showing an example of the state of the processing target area 10 after the second step is completed. In the second step, the insulating film 101 present in the processing target area 10 is removed by irradiation with the second laser. If a structure such as a TEG electrode is present in the processing target area 10, the structure present in the processing target area 10 is removed by irradiation with the second laser in the second step. As a result, a groove 110 is formed in the semiconductor wafer along the street 2, and the substrate 100 is exposed at the bottom of the groove 110. That is, in the second step, the insulating film 101 or structure present in the processing target area 10 is removed by laser ablation. Laser ablation is a phenomenon in which, when the irradiation intensity of laser light reaches a certain level or higher, electron, thermal, photochemical, and mechanical energy is exchanged on the surface of a solid, resulting in the emission of neutral atoms, molecules, positive and negative ions, clusters, electrons, and photons, and the generation of plasma with an electron temperature reaching several thousand degrees, thereby removing the surface of a solid.

[0033] By performing the first step before performing the second step, it is possible to reduce the energy of the second laser irradiated in the second step. The reason for this is presumed to be as follows: As shown in Fig. 4A, in the first step, unevenness 102 is formed on the surface of the insulating film 101 or structure present in the processing target region 10 by irradiating the first laser, thereby increasing the surface area of ​​the insulating film 101 or structure. This promotes energy absorption by the insulating film 101 or structure of the second laser irradiated in the second step, making it possible to remove the insulating film 101 or structure with the second laser having lower energy.

[0034] 4B , in the first step, the first laser irradiation generates cracks 103 in the insulating film 101 or structure present in the processing target region 10, thereby mechanically and thermally dividing the insulating film 101 or structure. This suppresses the diffusion and release of heat generated in the insulating film 101 or structure by the second laser irradiation in the second step, making it possible to remove the insulating film 101 or structure with the second laser having lower energy.

[0035] 4C , in the first step, voids 104 are formed in the insulating film 101 or structure present in the processing target region 10 by irradiating the first laser, thereby mechanically and thermally dividing the insulating film 101 or structure. This not only suppresses the diffusion and release of heat generated in the insulating film 101 or structure by irradiating the second laser in the second step, but also reduces the volume of the object to be removed, making it possible to remove the insulating film 101 or structure with the second laser having lower energy.

[0036] FIG. 10 is a diagram showing an example of the configuration of the second laser optical system 40 used in the second step. The second laser optical system 40 includes a laser oscillator 41, a beam shaper 43, and a lens 42. The semiconductor wafer 1 to be processed is held on a stage 50. The laser oscillator 41 outputs a second laser L2. The second laser L2 may be a UV pulse laser. The second laser L2 output from the laser oscillator 41 is shaped by the beam shaper 43 into an elongated spot shape as shown in FIG. 8, and is irradiated onto the surface of the semiconductor wafer 1 via the lens 42. The focus of the lens 42 is adjusted to the surface of the semiconductor wafer 1, and a spot of the second laser L2 is formed on the surface of the semiconductor wafer 1. By moving the stage 50 in the X and Y directions, the irradiation position of the second laser L2 can be moved along the processing target region 10. In order to avoid damage to the device and generation of debris due to heat, it is preferable to control the output of the laser oscillator 41 so that the energy per spot of the second laser L2 is 10 μJ or less.

[0037] The laser oscillator 41 may be the same as or different from the laser oscillator 31 constituting the first laser optical system 30. When a laser oscillator is shared between the first and second steps, a means for switching the optical path of the laser light output from the laser oscillator is provided. Alternatively, a means for switching between inserting into and retracting from the optical path optical elements such as lenses and beam shapers used in each step may be provided. Furthermore, the second laser optical system 40 may include a beam expander (not shown) for adjusting the beam diameter to an appropriate size and an attenuator (not shown) for adjusting the laser output.

[0038] As described above, the processing method according to the embodiment of the disclosed technology includes a first step of irradiating the processing target area 10 with a first laser L1 that forms a spot 11 whose length in the width direction (Y direction) of the processing target area 10 is shorter than the width of the processing target area 10 while scanning the processing target area 10, and a second step, after the first step, of irradiating the processing target area 10 with a second laser L2 that forms a spot 21 whose length in the width direction (Y direction) of the processing target area 10 corresponds to the width of the processing target area 10 while scanning the processing target area 10. In the first step, the first laser L1 is irradiated so that multiple scanning trajectories 12 of the spot 11 of the first laser L1 are aligned in the width direction (Y direction) of the processing target area 10.

[0039] In the first step, the first laser L1 is irradiated onto the processing target area 10 while scanning along the processing target area 10. The first laser L1 forms a spot 11 whose length d1 in the width direction (Y direction) of the processing target area 10 is shorter than the width W of the processing target area 10. The first laser L1 is irradiated so that multiple scanning trajectories of the spot 11 of the first laser L1 are aligned in the width direction (Y direction) of the processing target area 10. This results in the formation of at least one of irregularities 102, cracks 103, and voids 104 in the insulating film 101 or structure present in the processing target area 10. This promotes energy absorption in the insulating film 101 or structure by the second laser L2 irradiated in the second step. Alternatively, the diffusion and release of heat generated in the insulating film 101 or structure by the irradiation of the second laser L2 is suppressed. Therefore, the energy of the second laser L2 required to remove the insulating film 101 or structure can be reduced. In other words, according to the processing method according to the embodiment of the disclosed technology, it is possible to perform processing to form grooves along the streets that separate multiple devices provided on a semiconductor wafer using a laser with lower energy.

[0040] In laser grooving, damage to devices and generation of debris due to heat are problems. According to the processing method according to the embodiment of the disclosed technology, it is possible to address the heat problem without using an ultrashort pulse laser, which requires a large introduction cost. Furthermore, it is possible to appropriately remove insulating films or structures despite the low energy laser output.

[0041] FIG. 11A is an image showing the state of a street when a groove is formed along the street by a processing method according to a comparative example, and FIG. 11B is an image showing the state of a street when a groove is formed along the street by a processing method according to the disclosed technology. In the processing method according to the comparative example, the first step was not performed, and in the second step, a 10 μJ laser was scanned along the street twice. According to the processing method according to the comparative example, a portion of the TEG electrode, which is a structure present on the street, remained unremoved. On the other hand, in the processing method (Example) according to the disclosed technology, the first step was performed, and in the second step, an 8 μJ laser was scanned along the street once. According to the processing method according to the disclosed technology, even though the laser energy was smaller than that of the comparative example and only one scan was performed in the second step, the insulating film and structure present on the street were able to be removed without leaving any residue.

[0042] In the above description, a processing method including the first and second steps has been exemplified, but before or after the first step, edge cutting processing may be performed to form two parallel grooves along the street at both ends of the street. The technology described in JP 2021-192922 A can be applied to the edge cutting processing.

[0043] 12 is a plan view showing an example of a processing mode in a first step according to a second embodiment of the disclosed technique. In the second embodiment, as in the first embodiment described above, the first laser is irradiated in the first step so that multiple scanning trajectories 12 of the first laser spot 11 are aligned in the width direction (Y direction) of the processing target area 10.

[0044] In the second embodiment, as shown in FIG. 12 , a first laser beam is used to form multiple spots 11 arranged at different positions in the width direction (Y direction) of the processing target area 10 while irradiating the processing target area 10 and scanning the processing target area 10. The direction in which the multiple spots 11 are arranged may be perpendicular to the extension direction (X direction) of the processing target area 10 ( FIG. 12 ) or inclined ( FIG. 13 ). Even with this configuration, it is possible to form at least one of irregularities, cracks, and voids in the insulating film or structure present in the processing target area 10 upon completion of the first step. The shape of the first laser spot 11 is not particularly limited, but may be, for example, circular. Alternatively, as shown in FIGS. 14 and 15 , the shape of the first laser spot 11 may be rectangular or elliptical with the longitudinal direction of the spot oriented in the extension direction (X direction) of the processing target area 10.

[0045] 16 is a diagram showing an example of the configuration of a first laser optical system 30A used in the first step according to the second embodiment. The first laser optical system 30A has a laser oscillator 31, a diffractive optical element (DOE) 35, and a lens 32. That is, the first laser optical system 30A has a configuration in which the diffractive optical element 35 is added to the laser optical system 30 according to the first embodiment shown in FIG.

[0046] The first laser beam L1 output from the laser oscillator 31 is optically branched by passing through the diffractive optical element 35. As a result, a plurality of spots 11 arranged in a line are formed on the surface of the semiconductor wafer 1, as shown in FIGS. 12 and 13 . The diffractive optical element 35 is rotatable around the optical axis of the first laser beam L1 as the rotation axis. The arrangement direction of the plurality of spots 11 of the first laser beam L1 can be changed by changing the rotation angle of the diffractive optical element 35. The rotation angle of the diffractive optical element 35 is adjusted so that the plurality of spots 11 are positioned at different positions in the width direction (Y direction) of the processing target area 10. The stage 50 moves in the X and Y directions, allowing the irradiation position of the first laser beam to move along the processing target area 10. To avoid thermal damage to the device and the generation of debris, it is preferable to control the output of the laser oscillator 31 so that the energy per spot of the first laser beam L1 is 10 μJ or less.

[0047] 17 and 18 are diagrams showing other examples of the configuration of the first laser optical system 30A. As shown in Fig. 17, the first laser optical system 30A may include a beam shaper 33 for shaping the spot of the first laser L1 into a desired shape. Also, as shown in Fig. 18, the first laser optical system 30A may include a 4f optical system 34 for removing noise. Also, the first laser optical system 30A may include a beam expander (not shown) for adjusting the beam diameter to an appropriate size and an attenuator (not shown) for adjusting the laser output.

[0048] 19 is a diagram showing an example of a method for adjusting the rotation angle of the diffractive optical element 35. The rotation angle of the diffractive optical element 35 coincides with the tilt angle θ of the direction in which the multiple spots 11 are arranged relative to the direction in which the processing target area 10 extends (X direction). The tilt angle θ is expressed by the following formula (1). In formula (1), A1 is the length in the width direction (Y direction) of the processing target area 10 by the first laser. A1 may be the same as or slightly smaller than the width W of the processing target area 10. Also, in formula (1), A2 is the length from one end to the other end of the multiple spots 11 of the first laser. θ=Arc sin(A1 / A2) (1)

[0049] As described above, according to the processing method of the second embodiment of the disclosed technology, the first step includes scanning the processing target area 10 while irradiating the processing target area 10 with a first laser L1 that forms multiple spots 11 arranged at different positions in the width direction of the processing target area 10. According to the processing method of the second embodiment, similar to the processing method of the first embodiment, processing to form grooves along the streets 2 can be achieved using a laser with lower energy. Furthermore, because the first laser L1 forms multiple spots 11 arranged at different positions in the width direction of the processing target area 10, the number of scans required to align multiple scanning trajectories of the spots in the width direction of the processing target area 10 can be reduced compared to when the first laser L1 forms a single spot. This allows the processing time of the first step to be shortened compared to when the first laser L1 forms a single spot.

[0050] Although the above description has been given of an example in which the multiple spots 11 are spaced apart from one another, the multiple spots 11 may be connected in a line. That is, each spot 11 may partially overlap with an adjacent spot 11.

[0051] 20 is a plan view showing an example of a processing mode in the first step according to a third embodiment of the disclosed technique. In the third embodiment, similar to the first embodiment, the first laser is irradiated so that multiple scanning trajectories 12 of the first laser spot 11 are aligned in the width direction (Y direction) of the processing target region 10.

[0052] In the third embodiment, as shown in FIG. 20 , a first laser beam is irradiated onto the processing target area 10 and scanned along the processing target area 10, forming multiple spots 11 arranged at different positions in the width direction (Y direction) of the processing target area 10 and multiple spots 11 arranged at different positions in the scanning direction (X direction) of the first laser. This configuration also makes it possible to form at least one of irregularities, cracks, and voids in the insulating film or structure present in the processing target area 10 at the completion of the first step. The shape of the first laser spot 11 is not particularly limited, but may be, for example, circular. Alternatively, the shape of the first laser spot 11 may be rectangular or elliptical with the longitudinal direction of the spot oriented in the extension direction (X direction) of the processing target area 10.

[0053] 21 is a diagram showing an example of the configuration of a first laser optical system 30B used in the first step according to the third embodiment. The first laser optical system 30B according to the third embodiment has a laser oscillator 31, diffractive optical elements 35A and 35B, and a lens 32. That is, the first laser optical system 30B according to the third embodiment has a configuration in which two diffractive optical elements 35A and 35B are added to the laser optical system 30 according to the first embodiment shown in FIG.

[0054] The diffractive optical element 35A splits the first laser beam L1 output from the laser oscillator 31 in the width direction (Y direction) of the processing target area 10. The diffractive optical element 35B further splits the first laser beam L1 split by the diffractive optical element 35A in the extension direction (X direction) of the processing target area 10. As a result, multiple spots 11 arranged in a grid pattern are formed on the surface of the semiconductor wafer 1, as shown in FIG. 20 . The diffractive optical elements 35A and 35B are each rotatable around the optical axis of the first laser beam L1. The arrangement direction of the multiple spots 11 of the first laser beam L1 can be changed by changing the rotation angle of the diffractive optical elements 35A and 35B. The irradiation position of the first laser beam L1 can be moved along the processing target area 10 by moving the stage 50 in the X and Y directions. To avoid thermal damage to the device and the generation of debris, it is preferable to control the output of the laser oscillator 31 so that the energy per spot of the first laser beam L1 is 10 μJ or less.

[0055] 17 and 18 , the first laser optical system 30B may include a beam shaper for shaping the spot of the first laser L1 into a desired shape. The first laser optical system 30B may also include a 4f optical system for removing noise. The first laser optical system 30B may also include a beam expander (not shown) for adjusting the beam diameter to an appropriate size and an attenuator (not shown) for adjusting the laser output.

[0056] As described above, according to the processing method of the third embodiment of the disclosed technology, the first step includes scanning the processing target area 10 while irradiating the processing target area 10 with the first laser L1, which forms multiple spots 11 arranged at different positions in the width direction of the processing target area 10 and multiple spots 11 arranged at different positions in the scanning direction of the first laser. According to the processing method of the third embodiment, as with the processing method of the first embodiment, it is possible to achieve processing to form grooves along the streets 2 using a laser with lower energy. Furthermore, as with the processing method of the second embodiment, it is possible to reduce the number of scans required to align multiple scanning trajectories of the spots 11 in the width direction of the processing target area 10, thereby shortening the processing time of the first step.

[0057] The disclosures of Japanese Patent Application No. 2024-125250 filed on July 31, 2024 and Japanese Patent Application No. 2025-121977 filed on July 22, 2025 are incorporated herein by reference in their entirety. In addition, all documents, patent applications, and technical standards described herein are incorporated herein by reference to the same extent as if each individual document, patent application, and technical standard were specifically and individually indicated to be incorporated by reference.

Claims

1. A processing method for forming grooves along streets that separate multiple devices provided on a semiconductor wafer, comprising: a first step of irradiating the area to be processed with a first laser that forms a spot on the street whose length in the width direction of the area to be processed is shorter than the width of the area to be processed, while scanning the area to be processed; and a second step, after the first step, of irradiating the area to be processed with a second laser that forms a spot whose length in the width direction of the area to be processed corresponds to the width of the area to be processed, while scanning the area to be processed, wherein in the first step, the first laser is irradiated so that multiple scanning trajectories of the spot of the first laser are aligned in the width direction of the area to be processed.

2. A processing method as described in claim 1, wherein in the first step, the process of irradiating the area to be processed with the first laser, which forms a single spot, and scanning along the area to be processed is carried out multiple times while changing the irradiation position of the first laser in the width direction of the area to be processed.

3. The processing method according to claim 1, wherein the first laser forms a plurality of spots arranged at different positions in the width direction of the processing target area.

4. The processing method according to claim 3, wherein the first laser is irradiated so that the direction in which the plurality of spots are arranged is perpendicular to the direction in which the processing target area extends.

5. The processing method according to claim 3, wherein the first laser is irradiated so that the direction in which the plurality of spots are arranged is inclined with respect to the direction in which the processing target area extends.

6. A processing method according to claim 1, wherein the first laser forms a plurality of spots arranged at different positions in the width direction of the processing target area and a plurality of spots arranged at different positions in the scanning direction of the first laser.

7. A processing method as described in claim 1, wherein in the first step, unevenness is formed in a film or structure present in the processing target area by irradiating the first laser, or cracks or voids are formed in the film or structure.

8. A processing method as described in claim 1, wherein in the first step, the first laser is irradiated to divide or fracture a film or structure present in the processing target area, or to form irregularities on the surface of the film or structure.

9. The processing method according to claim 1, wherein in the second step, a film or structure present in the processing target area is removed by irradiating the second laser.

10. A processing device for forming grooves along streets that partition a plurality of devices provided on a semiconductor wafer, comprising: a first laser irradiation means that irradiates the area to be processed on the street with a first laser that forms a spot whose length in the width direction of the area to be processed on the street is shorter than the width of the area to be processed, while scanning the area to be processed; and a second laser irradiation means that irradiates the area to be processed with a second laser that forms a spot whose length in the width direction of the area to be processed corresponds to the width of the area to be processed, while scanning the area to be processed, while scanning the area to be processed; wherein the first laser irradiation means irradiates the first laser so that multiple scanning trajectories of the spot of the first laser are aligned in the width direction of the area to be processed.

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