Processing method and processing device

Abstract

In a first step, by scanning a first laser along a processing target region while irradiating the processing target region on a street with the first laser, at least one of a first region dividing a structure present on the processing target region or a second region facilitating the division of the structure is formed in the depth direction of the structure. In a second step following the first step, the structure is removed by scanning a second laser along the processing target region while irradiating the processing target region with the second laser.

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] The low-k film used as an insulating film in semiconductor devices has 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, in which a pulsed laser is used to remove the wiring layer, including the low-k film, along the streets that separate multiple devices on the semiconductor wafer.

[0006] Metallic structures such as TEG (Test Element Group) electrodes may be provided on the streets. In laser grooving, the structures on the streets are also subject to removal. When a laser is irradiated onto the structures, the impact of the laser can cause the structures to peel off and scatter in large chunks. When the scattered structures are irradiated with a laser, part of the laser is reflected by the structures and may be irradiated onto devices provided on the semiconductor wafer, potentially damaging the devices.

[0007] Furthermore, among the scattered removed materials, large chunks of the structure may fly away due to their large weight and slow movement speed, resulting in the risk of remaining on the street for a long time and blocking the laser. In this case, laser irradiation of the street may be insufficient, reducing processing efficiency. Furthermore, the scattered removed materials may be heated by the laser, raising the temperature of the atmosphere in the vicinity of the processing point, causing the scattered removed materials to melt and adhere to the surrounding area, generating debris and deteriorating the groove shape. As a result, problems such as a decrease in the die strength of the device or a deterioration in the device's electrical characteristics may occur.

[0008] The disclosed technology has been made in consideration of the above points, and aims to suppress the occurrence of defects caused by scattering of structures present on the streets during processing to form grooves along the streets that separate multiple devices provided on a semiconductor wafer.

[0009] A processing method according to the disclosed technology is a processing method for forming grooves along streets that separate multiple devices on a semiconductor wafer. This processing method includes a first step of irradiating a processing target area on the street with a first laser while scanning the processing target area along the processing target area to form at least one of a first region that divides a structure present in the processing target area and a second region that facilitates dividing the structure in a depth direction of the structure, and a second step of removing the structure by irradiating the processing target area with a second laser while scanning the processing target area along the processing target area after the first step.

[0010] The structure may include a metal. The structure may include a TEG electrode.

[0011] The first laser may form a spot whose length in the width direction of the area to be processed is shorter than the width of the area to be processed, and the second laser may form a spot whose length in the width direction of the area to be processed is a length corresponding to the width of the area to be processed.

[0012] The process of scanning the first laser beam forming a single spot along the target processing area while irradiating the target processing area with the first laser beam forming a single spot may be performed at least once. The process of scanning the first laser beam forming a single spot along the target processing area while irradiating the target processing area with the first laser beam forming a single spot may be performed multiple times while changing the irradiation position of the first laser beam in the width direction of the target processing area.

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

[0014] 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 an extension direction of the street.

[0015] A processing apparatus according to the disclosed technology is a processing apparatus for forming grooves along streets that separate 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 while scanning the processing target area along the processing target area to form at least one of a first region that divides a structure present in the processing target area and a second region that facilitates division of the structure in the depth direction of the structure; and a second laser irradiation means that irradiates the processing target area with a second laser while scanning the processing target area along the processing target area to remove the structure.

[0016] The disclosed technology aims to suppress defects caused by scattering of structures present on the streets during processing to form grooves along streets that separate multiple devices provided on a semiconductor wafer.

[0017] 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 cross-sectional view taken along line 2-2 in FIG. 1. FIG. 1 is a cross-sectional view taken along line 2-2 in FIG. 1. FIG. 1 is a cross-sectional view taken along line 2-2 in FIG. 1. 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. 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 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. 2 is a diagram showing another ...3 is a plan view showing an example of a processing mode in a second step according to an embodiment of the disclosed technology. FIG. 4 is a cross-sectional view showing an example of a state of a street after completion of a second step according to an embodiment of the disclosed technology. FIG. 5 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. 6 is a diagram showing an example of a defect caused by scattering of a structure present on a street. FIG. 7 is a diagram showing an example of a defect caused by scattering of a structure present on a street. FIG. 8 is a plan view showing an example of a processing mode in a first step according to another embodiment of the disclosed technology. 13A and 13B are cross-sectional views taken along line 14-14 in FIG. 13A and 13B are cross-sectional views taken along line 14-14 in FIG. 13A and 13B are plan views showing an example of a mode of processing in a first step according to another embodiment of the disclosed technology. A plan view showing an example of a mode of processing in a first step according to another embodiment of the disclosed technology. A plan view showing an example of a mode of processing in a first step according to another embodiment of the disclosed technology. A plan view showing an example of a mode of processing in a first step according to another embodiment of the disclosed technology. 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. 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. 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. 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 technology.10A and 10B are plan views showing an example of a processing mode in a first step according to another embodiment of the disclosed technique, and are diagrams 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.

[0018] 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.

[0019] 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 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 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.

[0020] [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. FIGS. 2A and 2B are cross-sectional views (Y-Z cross-sectional views) taken along line 2-2 in FIG. 1 . In the first step, a first laser is irradiated onto a processing target area 10 set on a street 2 while scanning the processing target area 10. As a result, as shown in FIG. 2A , a division region 61 that divides a structure 60 present in the processing target area 10 is formed throughout the depth direction (Z direction) of the structure 60. Alternatively, as shown in FIG. 2B , an altered region 62 that facilitates division of the structure 60 is formed throughout the depth direction of the structure 60. As shown in FIG. 2C , the division region 61 may be formed in a portion of the structure 60 in the depth direction, and the altered region 62 may be formed in another portion of the structure 60 in the depth direction. The division region 61 is an example of a "first region" in the disclosed technology. The affected region 62 is an example of a "second region" in the disclosed technology.

[0021] The structure 60 may be, for example, a metal such as a TEG electrode. The structure 60 being divided across its entire depth means that the structure 60 is divided into two or more fragments by a crack or void extending in the depth direction. The altered region 62 includes, for example, a region where the structure 60 is physically altered due to damage or the like, and a region where the structure 60 is chemically altered due to a change in composition or the like.

[0022] In the first step, the first laser irradiated onto the processing target area 10 forms a spot 11 having a length d1 in the width direction (Y direction) of the processing target area 10 that is shorter than the width W of the processing target area 10. In the first step, a process of scanning along the processing target area 10 while irradiating the processing target area 10 with the first laser that forms the single spot 11 is performed at least once. As a result, at least one scanning trajectory 12 of the first laser spot 11 along the processing target area 10 is formed.

[0023] The shape of the first laser spot 11 is not particularly limited, and may be, for example, a circle. Alternatively, as shown in Figures 3 and 4, the shape of the first laser spot 11 may be a rectangle or an ellipse with the longitudinal direction of the spot oriented in the direction in which the processing target region 10 extends (X direction).

[0024] 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 has 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.

[0025] In order to form at least one of a dividing region 61 that divides the structure 60 present in the processing area 10 and an altered region 62 that makes it easier to divide the structure 60 throughout the entire depth direction of the structure 60, at least one of the energy of the first laser L1, the movement speed of the stage 50 and the overlap rate (degree of overlap of the spots) is adjusted.

[0026] 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.

[0027] 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 while scanning along the processing target area 10, thereby removing the structure 60 present in 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 equal to 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.

[0028] 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 and the structure 60 present on the processing target area 10 are removed by irradiation with the second laser. As a result, a groove 110 is formed in the semiconductor wafer along the processing target area 10, and the substrate 100 is exposed at the bottom of the groove 110. That is, in the second step, the insulating film 101 or the structure 60 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, energy is exchanged on the surface of a solid for electrons, thermal, photochemical, and mechanical energy, 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.

[0029] 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.

[0030] 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.

[0031] As described above, the processing method according to an embodiment of the disclosed technology includes a first step of forming at least one of a dividing region 61 that divides the structure 60 present in the processing target area 10 on the street 2 and an altered region 62 that facilitates dividing the structure 60 throughout the entire depth direction of the structure 60 by irradiating the processing target area 10 on the street 2 with a first laser L1 and scanning it along the processing target area 10, and a second step of removing the structure 60 after the first step by irradiating the processing target area 10 with a second laser L2 and scanning it along the processing target area 10.

[0032] Here, assume that only the second step is performed without performing the first step. As shown in Figure 11, when the second laser L2 is irradiated onto the structure 60 present in the processing target area 10 in the second step, the structure 60 may be peeled off and scattered in large chunks due to the impact of the second laser L2. When the scattered structure 60 is irradiated with the second laser L2, a portion of the second laser L2 is reflected by the structure 60 and irradiated onto the device 102 provided on the semiconductor wafer, which may damage the device 102.

[0033] 12, among the scattered removed material, large chunks of structure 60 may remain over the processing target area 10 for a long time due to their large weight, potentially blocking the second laser beam L2. In this case, the laser irradiation of the processing target area 10 may be insufficient, reducing the processing efficiency. Furthermore, the scattered removed material may be heated by the laser, causing the atmosphere in the processing vicinity to become hot, melting the scattered removed material and adhering to the surrounding area, generating debris and deteriorating the shape of the groove. As a result, problems such as a reduction in the flexural strength of the device 102 or a deterioration in the electrical characteristics of the device 102 may occur.

[0034] On the other hand, according to the processing method according to the embodiment of the disclosed technology, in the first step performed before the second step, at least one of a division region 61 that divides the structure 60 and an altered region 62 that facilitates division of the structure 60 is formed throughout the entire depth direction of the structure 60 by irradiating the first laser L1. By dividing the structure 60 in the first step, it is possible to prevent the structure 60 from peeling off and scattering as a large mass in the second step. In other words, even if the structure 60 scatters, it scatters in the form of small fragments. Even if the second laser L2 is reflected by small fragments of the scattered structure 60 and irradiated onto a device, the energy of the reflected light from the small fragments is small, thereby reducing the risk of the device being damaged by the reflected light. Furthermore, since the altered region 62 is formed throughout the entire depth direction of the structure 60 in the first step, the structure 60 is immediately divided by the irradiation of the second laser L2 in the second step, and even if the structure 60 is scattered, it is scattered in the form of small fragments. This makes it possible to reduce the risk of the device being damaged by the reflected light of the second laser L2, just as in the case where the structure 60 is divided in the first step.

[0035] Furthermore, by breaking the structure 60 into small fragments, its weight decreases and its movement speed increases, preventing the structure 60 from remaining on the processing target area 10 for a long time. This prevents the second laser L2 from being blocked by the scattered structure 60, preventing insufficient laser irradiation of the processing target area 10. This reduces the risk of reduced processing efficiency and debris generation that deteriorates the shape of the groove due to the scattering of the structure 60. As a result, the occurrence of problems such as a decrease in the flexural strength of the device and deterioration of the electrical characteristics of the device is suppressed.

[0036] As described above, according to the processing method according to the embodiment of the disclosed technology, in processing to form grooves along streets that separate multiple devices provided on a semiconductor wafer, it is possible to suppress the occurrence of defects due to scattering of structures present on the streets.

[0037] 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.

[0038] [Second Embodiment] FIG. 13 is a plan view showing an example of the processing mode in the first step according to a second embodiment of the disclosed technology. FIGS. 14A and 14B are cross-sectional views (Y-Z cross-sectional views) taken along line 14-14 in FIG. 13 . In the processing method according to the second embodiment, as shown in FIG. 13 , in the first step, a first laser beam forming a single spot 11 is irradiated onto the processing target area 10 while scanning along the processing target area 10. This process is performed multiple times while changing the irradiation position of the first laser beam in the width direction (Y direction) of the processing target area 10. That is, in the first step, the first laser beam is irradiated so that multiple scanning trajectories 12 of the first laser beam spot 11 are aligned in the width direction (Y direction) of the processing target area 10. As a result, as shown in FIG. 14A , division regions 61 of the structure 60 are formed at multiple positions in the width direction (Y direction) of the processing target area 10. Alternatively, as shown in FIG. 14B, affected regions 62 of the structure 60 are formed at a plurality of positions in the width direction (Y direction) of the processing target region 10.

[0039] According to the processing method of the second embodiment of the disclosed technology, it is possible to break the structure 60 into smaller fragments. As a result, in the second step, the energy of the reflected light of the second laser generated by the fragments of the structure 60 can be reduced, thereby enhancing the effect of reducing the risk of the device being damaged by the reflected light. It is also possible to enhance the effect of avoiding blocking of the second laser L2 by the structure 60. Therefore, according to the processing method of the second embodiment of the disclosed technology, it is possible to enhance the effect of reducing the occurrence of defects due to scattering of structures present on the street.

[0040] 15 is a plan view showing an example of a processing mode in the first step according to a third embodiment of the disclosed technology. In the third embodiment, a first laser that forms multiple spots 11 arranged at different positions in the width direction (Y direction) of the processing target area 10 is irradiated onto the processing target area 10 and scanned along 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. 15 ) or may be inclined ( FIG. 16 ).

[0041] The shape of the spot 11 of the first laser is not particularly limited, and may be, for example, a circle. Alternatively, as shown in Figures 17 and 18, the shape of the spot 11 of the first laser may be a rectangle or an ellipse with the longitudinal direction of the spot oriented in the direction in which the processing target region 10 extends (X direction).

[0042] 19 is a diagram showing an example of the configuration of a first laser optical system 30A used in the first step according to the third 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.

[0043] The first laser 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 FIG. 16 . The diffractive optical element 35 is rotatable around the optical axis of the first laser L1 as the rotation axis. By changing the rotation angle of the diffractive optical element 35, the arrangement direction of the plurality of spots 11 of the first laser L1 can be changed. 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. By moving the stage 50 in the X and Y directions, the irradiation position of the first laser can be moved along the processing target area 10.

[0044] 20 and 21 are diagrams showing other examples of the configuration of the first laser optical system 30A. As shown in Fig. 20, 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. 21, the first laser optical system 30A may include a 4f optical system 34 for removing noise. Furthermore, 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.

[0045] 22 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. A1 may be the same as or slightly smaller than the width of the street 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)

[0046] 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 a first laser L1, which forms multiple spots 11 arranged at different positions in the width direction of the processing target area 10. The processing method of the third embodiment, like the processing method of the second embodiment, can enhance the effect of suppressing defects caused by scattering of structures present on the street. 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 form multiple spot scanning trajectories 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.

[0047] 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.

[0048] [Fourth Embodiment] Figure 23 is a plan view showing an example of the processing mode in the first step according to a fourth embodiment of the disclosed technology. In the fourth embodiment, as in the first embodiment described above, the first laser is irradiated so that multiple scanning trajectories 12 of the first laser spot 11 are formed in the width direction (Y direction) of the processing target area 10. In the fourth embodiment, the first laser, which forms 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 extension direction (X direction) of the processing target area 10, is irradiated onto the processing target area 10 and scanned along the processing target area 10. 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.

[0049] 24 is a diagram showing an example of the configuration of a first laser optical system 30B used in the first step according to the fourth embodiment. The first laser optical system 30B according to the fourth 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 fourth 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.

[0050] The diffractive optical element 35A splits the first laser 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 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. 23 . The diffractive optical elements 35A and 35B are each rotatable around the optical axis of the first laser L1. By changing the rotation angle of the diffractive optical elements 35A and 35B, the arrangement direction of the multiple spots 11 of the first laser L1 can be changed. 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 area 10.

[0051] 20 and 21 , 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.

[0052] As described above, according to the processing method of the fourth embodiment of the disclosed technology, in the first step, 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 extension direction of the processing target area 10, is irradiated onto the processing target area 10 and scanned along the processing target area 10. The processing method of the fourth embodiment can achieve the same effect as the processing method of the third embodiment. That is, it is possible to enhance the effect of suppressing the occurrence of defects due to scattering of structures present on the street. Furthermore, it is possible to shorten the processing time of the first step compared to when the first laser L1 forms a single spot.

[0053] The disclosures of Japanese Patent Application No. 2024-125251 filed on July 31, 2024 and Japanese Patent Application No. 2025-121978 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 a processing target area on the street with a first laser while scanning the processing target area along the area to be processed, thereby forming at least one of a first region that separates a structure present in the processing target area and a second region that facilitates separation of the structure in the depth direction of the structure; and a second step, after the first step, of removing the structure by irradiating the processing target area with a second laser while scanning the processing target area along the area to be processed.

2. The processing method according to claim 1, wherein the structure comprises a metal.

3. The processing method according to claim 2, wherein the structure includes a TEG electrode.

4. A processing method as described in claim 1, wherein the first laser forms a spot whose length in the width direction of the area to be processed is shorter than the width of the area to be processed, and the second laser forms a spot whose length in the width direction of the area to be processed is a length corresponding to the width of the area to be processed.

5. The processing method according to claim 1, wherein the process of scanning the first laser, which forms a single spot, along the processing target area while irradiating the processing target area is carried out at least once.

6. A processing method as described in claim 1, in which 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.

7. 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.

8. The processing method according to claim 7, 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.

9. The processing method according to claim 7, wherein the first laser is irradiated in a state in which the direction in which the plurality of spots are arranged is inclined with respect to the width direction of the processing target area.

10. 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.

11. A processing device for forming grooves along streets that separate multiple devices provided on a semiconductor wafer, comprising: a first laser irradiation means that irradiates a processing target area on the street with a first laser while scanning the processing target area along the processing target area, thereby forming at least one of a first region that separates a structure present in the processing target area and a second region that facilitates separation of the structure in the depth direction of the structure; and a second laser irradiation means that irradiates the processing target area with a second laser while scanning the processing target area along the processing target area, thereby removing the structure.

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