Dicing method and dicing system

Abstract

To provide a dicing method and a dicing system that can reduce blade wear.SOLUTION: A dicing method includes a laser processing step of performing laser processing on a wafer 10, and a blade processing step of performing cutting processing on the laser-processed wafer 10 using a blade 32 to cut the wafer 10. In the laser processing step, a laser is radiated onto the inside of the wafer 10, and a modified layer 15 is formed in a cutting region 12 cut by the blade 32. The modified layer 15 is formed in a region inside a first processed surface 10a and a second processed surface 10b, which are end faces in the thickness direction of the wafer.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a dicing method and a dicing system. [Background technology]

[0002] Wafers on which various elements such as semiconductor devices and electronic components are formed are divided into individual chips by dicing along dicing lines. For example, Patent Document 1 discloses a dicing method in which a modified layer is formed on the wafer by laser processing, and then the wafer is diced by cutting the wafer with a blade.

[0003] The dicing method described in Patent Document 1 will be described with reference to Fig. 13. Fig. 13 is a diagram for explaining a conventional dicing method. In Fig. 13, the direction perpendicular to the paper surface is the direction of blade movement.

[0004] 13, in Patent Document 1, modified layers 102 are formed on both sides of the blade 101 in the traveling direction in order to prevent chipping from occurring near the back surface 100b of the wafer 100 during cutting processing by the blade 101. The modified layers 102 are formed so as to be exposed on the back surface 100b of the wafer 100. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-247156 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the method of Patent Document 1, the blade is prone to wear when cutting a wafer made of a difficult-to-cut material such as silicon carbide (SiC). [Means for solving the problem]

[0007] A dicing method for solving the above problems includes a laser processing step for performing laser processing on a wafer, and a blade processing step for performing cutting processing on the wafer after the laser processing using a blade to cut the wafer. In the laser processing step, a laser is irradiated into the interior of the wafer, and a modified layer is formed in a region cut by the blade that is inside the edge surface of the wafer in the thickness direction. [Effects of the Invention]

[0008] According to the present invention, wear on the blade can be reduced. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a plan view schematically showing a wafer to be diced by an embodiment of a dicing method. [Figure 2] FIG. 2 is a flowchart showing the procedure of the dicing method. [Figure 3] FIG. 3 is a diagram schematically showing a cross section of a wafer in the vicinity of a dicing line after laser processing. [Figure 4] FIG. 4 is a diagram schematically illustrating a general configuration of an example of a laser processing device. [Figure 5] FIG. 5 is a graph showing an example of the relationship between the wavelength of a laser and the transmittance. [Figure 6] FIG. 6 is a diagram schematically showing the state of laser processing by the laser processing device. [Figure 7] FIG. 7 is a diagram schematically showing a state immediately before laser processing by the laser processing device is completed. [Figure 8] FIG. 8 is a diagram schematically showing another example of the position where the modified layer is formed, together with a laser processing device. [Figure 9] FIG. 9(a) is a diagram schematically showing another example of the position where the modified layer is formed, and FIG. 9(b) is a diagram schematically showing another example of the position where the modified layer is formed. [Figure 10]Figure 10(a) is a diagram showing a schematic diagram of another example of a position where a modified layer is formed, Figure 10(b) is a diagram showing a schematic diagram of another example of a position where a modified layer is formed, and Figure 10(c) is a diagram showing a schematic diagram of another example of a position where a modified layer is formed. [Figure 11] FIG. 11 is a diagram schematically showing the blade processing performed by the blade processing device. [Figure 12] FIG. 12 is a block diagram showing a schematic configuration of an embodiment of a dicing system. [Figure 13] FIG. 13 is a diagram for explaining a conventional dicing method. DETAILED DESCRIPTION OF THE INVENTION

[0010] An embodiment of a dicing method and a dicing system will be described with reference to FIGS. As shown in FIG. 1, the wafer 10 is divided into individual chips by dicing along grid-like dicing lines 11. The surface of the wafer 10 on which various elements such as semiconductor devices and electronic components are formed is referred to as the first processing surface 10a, and the surface opposite the first processing surface 10a is referred to as the second processing surface 10b (see FIG. 3). The wafer 10 is a difficult-to-cut material. In this embodiment, the wafer 10 is a silicon carbide wafer made of silicon carbide (SiC). In a SiC wafer 10, the first processing surface 10a is the Si-face, and the second processing surface 10b is the C-face. Note that the wafer 10 that falls under the category of difficult-to-cut materials is not limited to those made of silicon carbide. For example, wafers 10 made of silicon, sapphire, gallium nitride (GaN), gallium oxide (Ga2O3), gallium arsenide (GaAs), or the like also fall under the category of difficult-to-cut materials.

[0011] (Outline of dicing method) The dicing method will be outlined with reference to FIGS. 2, the dicing method includes a laser processing step (step S101) and a blade processing step (step S102). In the laser processing step, laser processing is performed on the wafer 10 using a laser processing device along dicing lines 11. In the blade processing step, cutting processing is performed on the wafer 10 after laser processing using a blade processing device along dicing lines 11.

[0012] FIG. 3 is a diagram schematically showing a cross section of wafer 10 near dicing line 11 after laser processing. In FIG. 3, dicing line 11 extends in a direction perpendicular to the plane of the page. In FIG. 3, blade 32 is shown by a two-dot chain line to show the positional relationship between wafer 10 and blade 32. As shown in FIG. 3, the area of ​​wafer 10 that is cut by blade 32 is called cutting area 12. Cutting area 12 extends along dicing line 11. Cutting area 12 has a width corresponding to the blade width W of blade 32. Blade width W is, for example, 20 to 40 μm.

[0013] In the laser processing step, a laser is irradiated onto the wafer 10, thereby forming a modified layer 15 in the cutting region 12. In the blade processing step, the cutting region 12 where the modified layer 15 has been formed is cut with a blade 32, thereby cutting the wafer 10 along the dicing lines 11.

[0014] In the following description, the planar direction in which the first processing surface 10a and the second processing surface 10b of the wafer 10 extend is referred to as the XY direction, one direction in the XY direction is referred to as the X direction, and the direction perpendicular to the X direction in the XY direction is referred to as the Y direction. The X direction is the direction in which the dicing lines 11 to be processed in each process extend. In the blade processing process, the Y direction is the width direction of the blade 32. The direction perpendicular to the XY direction is referred to as the Z direction. The Z direction is the thickness direction of the wafer 10.

[0015] (Laser processing process) The laser processing step (step S101) will be described in detail with reference to Figures 4 to 10. First, a schematic configuration of an example of a laser processing device will be described.

[0016] As shown in Fig. 4, the laser processing device 20 has a work table 21 and a laser irradiation unit 22. The work table 21 supports the second processing surface 10b of the wafer 10 via the dicing tape 16. The work table 21 is configured to be rotatable around the Z direction as the rotation axis. The work table 21 and the laser irradiation unit 22 are configured to be relatively movable in the X and Y directions.

[0017] The laser irradiation unit 22 irradiates the wafer 10 supported on the work table 21 with a laser beam LB. The laser irradiation unit 22 has a laser emission unit 23 and a condenser lens 24. The laser emission unit 23 and the condenser lens 24 are configured to be relatively movable in the Z direction. The laser emission unit 23 emits the laser beam LB toward the condenser lens 24. In this embodiment, the laser beam LB is a pulsed laser. The condenser lens 24 focuses the laser beam LB emitted by the laser emission unit 23 at a focusing point P. The focusing point P is the irradiation position of the laser beam LB.

[0018] The laser processing device 20 adjusts the irradiation position of the laser LB in the X and Y directions by the relative movement of the work table 21 and the laser irradiation unit 22. The relative speed of the laser irradiation unit 22 with respect to the work table 21 is called the laser processing speed. The laser processing speed is set according to the material and thickness of the wafer 10. For example, when the thickness of the wafer 10 is 100 to 200 μm, the laser processing speed is set to 800 to 2000 mm / sec.

[0019] Furthermore, the laser processing device 20 adjusts the irradiation position of the laser LB in the Z direction by moving the laser emission unit 23 and the condenser lens 24 relative to each other. The laser processing device 20 moves the laser emission unit 23 and the condenser lens 24 relative to each other so that the irradiation position is on the internal region of the wafer 10. When the laser LB is irradiated, a modified layer 15 with a destroyed crystalline structure is formed in the cutting region 12 near the focal point P of the laser LB. The modified layer 15 is a region that is more fragile than a portion not subjected to laser processing. The laser processing device 20 forms the modified layer 15 in a region inside the end face of the wafer 10 in the Z direction, i.e., in a region inside the first processing surface 10a and the second processing surface 10b.

[0020] The wavelength of the laser LB is determined based on the material of the wafer 10. From the viewpoint of efficiently forming the modified layer 15, the laser LB preferably has high transmittance with respect to the wafer 10.

[0021] Figure 5 is a graph showing an example of the relationship between laser wavelength and transmittance for a 100 μm thick silicon carbide wafer. As shown in Figure 5, the laser transmittance for the wafer varies depending on the wavelength. Furthermore, the laser has a peak wavelength λ1 corresponding to the peak transmittance T1, which is the highest transmittance.

[0022] In light of this, the wavelength of the laser LB is preferably a wavelength corresponding to a transmittance ratio of 0.8 or more relative to the peak transmittance T1. It is more preferable that the wavelength of the laser LB is a wavelength corresponding to a ratio of 0.95 or more relative to the peak transmittance T1. Furthermore, it is preferable that the wavelength of the laser LB is within a range of ±300 nm relative to the peak wavelength λ1. It is more preferable that the wavelength of the laser LB is within a range of ±200 nm relative to the peak wavelength λ1. It is even more preferable that the wavelength of the laser LB is within a range of ±100 nm relative to the peak wavelength λ1. In the example shown in FIG. 5, the wavelength of the laser LB is preferably within a range of 500 nm to 1200 nm, and more preferably within a range of 700 nm to 900 nm.

[0023] The laser processing conditions of the laser processing device 20 include the material of the wafer 10, the thickness of the wafer 10, the laser processing speed, the wavelength of the laser LB, and the output of the laser LB. The laser processing conditions are set to conditions under which a modified layer 15 that is not exposed on the first processing surface 10a and the second processing surface 10b is formed in the cutting region 12. The laser processing conditions are set to conditions under which the modified layer 15 is formed without protruding from the cutting region 12.

[0024] Next, an example of laser processing using the above-mentioned laser processing apparatus 20 will be described. In the laser processing apparatus 20, the work table 21 supports the wafer 10 via the dicing tape 16. The laser irradiation unit 22 is also adjusted so that the irradiation position of the laser LB is the internal region of the wafer 10.

[0025] As shown in Fig. 6, first, the laser processing device 20 rotates the work table 21 around the Z direction as the rotation axis so that the dicing line 11 to be irradiated is aligned with the X direction. The laser processing device 20 also moves the work table 21 and the laser irradiation unit 22 relatively in the X and Y directions so that the laser irradiation unit 22 is positioned at a start position. The start position is a position where the laser irradiation unit 22 faces one end of the dicing line 11 to be irradiated in the Z direction. Note that in Fig. 6 and other figures, the arrows overlapping the modified layers 15 indicate the order in which the modified layers 15 are formed.

[0026] Next, the laser processing device 20 moves the work table 21 and the laser irradiation unit 22 relatively in the X direction while emitting the laser beam LB from the laser emission unit 23. As a result, modified layers 15 are formed in the cutting region 12 at intervals and with sizes according to the laser processing conditions.

[0027] 7, the laser processing device 20 moves the work table 21 and the laser irradiation unit 22 relative to each other in the X direction until the other end of the dicing line 11 faces the laser irradiation unit 22 in the Z direction. As a result, a plurality of modified layers 15 aligned in the X direction are formed in the cutting region 12.

[0028] The laser processing conditions of the laser processing device 20 are set so that the width of the modified layer 15 in the Z direction is 30 to 50 μm. The laser processing conditions of the laser processing device 20 are also set so that the width of the modified layer 15 in the X and Y directions is about 5 μm. Note that laser processing using the laser processing device 20 may be repeated until the desired brittleness is obtained in each modified layer 15.

[0029] The modified layer 15 can also be formed at a plurality of positions in the Z direction. 8, a modified layer 15A located closer to the second processing surface 10b and a modified layer 15B located closer to the first processing surface 10a may be formed in the cutting region 12. In this case, it is preferable that the modified layer 15A located closer to the second processing surface 10b be formed first in the laser processing step, as shown by the arrow.

[0030] For example, as shown in FIG. 9(a), three or more modified layers 15C may be formed in the cutting region 12 at different positions in the Z direction. For example, as shown in Fig. 9(b), a modified layer 15D may be formed in the cutting region 12, in which modified layers 15E, 15F, and 15G at different positions in the Z direction partially overlap. Such a modified layer 15D is used when the output of the laser LB is low or the transmittance of the laser LB to the wafer 10 is low, or when it is desired to make a specific position brittle in a concentrated manner. Note that, although the modified layer 15D is formed near the first processing surface 10a in Fig. 9(b), the modified layer 15D may also be formed near the second processing surface 10b.

[0031] Here, the number and width of the modified layers 15 in the Z direction are preferably set so that the modified layers 15 occupy an area of ​​30% or more and less than 100% of the cutting area 12 in the Z direction. It is more preferable that the number and width of the modified layers 15 in the Z direction are set so that the modified layers 15 occupy an area of ​​50% or more and less than 80% of the cutting area 12 in the Z direction.

[0032] The modified layer 15 can also be formed at a plurality of positions in the Y direction. For example, as shown in FIG. 10(a), two modified layers 15 may be formed in the cutting region 12 so as to be evenly spaced in the Y direction.

[0033] For example, as shown in FIG. 10(b), two modified layers 15 may be formed in the cutting region 12 so as to be located at each end in the Y direction. For example, as shown in Figure 10(c), one or more modified layers 15 may be formed in the cutting area 12 between two modified layers 15 aligned in the Y direction in Figure 10(b), so that three or more modified layers 15 are aligned in the Y direction.

[0034] The positions at which the modified layers 15 are formed shown in each of Figures 7 to 10 may be combined arbitrarily. For example, the modified layers 15A and 15B shown in Figure 8 may be formed at different positions in the Y direction in the cutting region 12. For example, the modified layers 15 arranged in the Y direction shown in Figures 10(a) to 10(c) may be formed at different positions in the Z direction in the cutting region 12. The modified layers 15 formed at different positions in the Z direction or the Y direction may be formed at the same time using a spatial modulation element or the like.

[0035] In the laser processing step, the laser processing device 20 performs laser processing on the cutting areas 12 corresponding to the dicing lines 11. As a result, a plurality of modified layers 15 are formed in each cutting area 12 along the dicing lines 11.

[0036] (Blade processing process) The blade processing step (step S102) will be described in detail with reference to Fig. 11. First, a schematic configuration of an example of a blade processing device 30 that performs cutting processing will be described.

[0037] As shown in Fig. 11, the blade processing device 30 has a chuck table 31 and a blade 32. The chuck table 31 suction-holds the wafer 10 via the dicing tape 16. The chuck table 31 is configured to be rotatable around the Z direction as the rotation axis. The chuck table 31 and the blade 32 are configured to be relatively movable in the X, Y, and Z directions.

[0038] The blade 32 is formed in a disk shape. The blade 32 is attached to a spindle 33 that rotates at high speed around the Y direction as its rotation axis. The rotation direction of the blade 32 is the direction in which the blade 32 enters the wafer 10 from the second processing surface 10b. The blade processing device 30 cuts the cutting region 12 along the dicing line 11 by moving the chuck table 31 and the blade 32 relative to each other in the X direction while rotating the blade 32. The relative speed between the chuck table 31 and the blade 32 is referred to as the blade processing speed. The blade processing speed is set depending on the material and thickness of the wafer 10, the conditions for forming the modified layer 15 (laser processing conditions), etc. For example, when the thickness of the wafer 10 is 100 to 200 μm, the blade processing speed is set to 10 to 20 mm / sec.

[0039] Next, a description will be given of an example of cutting processing using the above-described blade processing device 30. It is assumed that the chuck table 31 holds the wafer 10 by suction. 11, the blade processing device 30 performs various position adjustments. Specifically, the blade processing device 30 rotates the chuck table 31 about the Z direction as the rotation axis so that the dicing line 11 to be cut is aligned along the X direction.

[0040] The blade processing device 30 moves the chuck table 31 and the blade 32 relative to each other so that the blade 32 is located at the start position. Specifically, the blade processing device 30 moves the chuck table 31 and the blade 32 relative to each other in the X and Y directions so that the blade 32 is located on one side in the X direction of the cutting region 12 to be cut. The blade processing device 30 also moves the chuck table 31 and the blade 32 relative to each other in the Z direction so that the blade 32 can cut the wafer 10 and a portion of the dicing tape 16.

[0041] After various position adjustments are completed, the blade processing device 30 cuts the cutting areas 12 along the dicing lines 11 by moving the chuck table 31 and the blade 32 relatively in the X direction while rotating the blade 32 around the Y direction as the rotation axis. In the blade processing step, blade processing is performed on the cutting areas 12 corresponding to each dicing line 11. As a result, the wafer 10 is divided into individual chips.

[0042] (action) In the above-described dicing method, the modified layer 15 is formed in the cutting region 12 by laser processing, and then the cutting region 12 is cut by cutting processing. In the cutting processing, the blade 32 cuts the cutting region 12, a portion of which has been made embrittled by the modified layer 15.

[0043] (dicing system) The dicing system 50 will be described with reference to FIG. As shown in FIG. 12, the dicing system 50 includes a laser processing device 20, a blade processing device 30, a transport device 53, and a control device .

[0044] The laser processing device 20 performs laser processing to form a modified layer 15 in the cutting region 12. The blade processing device 30 performs cutting processing on the wafer 10 after laser processing. The transport device 53 is configured to be able to transport the wafer 10 after laser processing from the laser processing device 20 to each blade processing device 30. The transport device 53 may be configured to transport the wafer 10 between the work table 21 and the chuck table 31. Alternatively, the transport device 53 may be a chuck table that can move back and forth between the laser processing device 20 and the blade processing device 30.

[0045] The control device 54 is mainly composed of a microcontroller in which a processor, memory, input interface, output interface, etc. are connected to one another via a bus. The control device 54 acquires various types of information via the input interface. The control device 54 then executes various processes based on the acquired information, as well as the programs and various data stored in the memory.

[0046] The control device 54 executes a process of determining the operating status of the laser processing device 20 by communicating with the laser processing device 20. In this process, the control device 54 determines the progress of laser processing in the laser processing device 20 as the operating status. The control device 54 executes a process of determining the operating status of each blade processing device 30 by communicating with each blade processing device 30. In this process, the control device 54 determines whether the blade processing device 30 is in a standby state or an operating state as the operating status. Furthermore, the control device 54 determines the progress of cutting processing for blade processing devices 30 that are in an operating state. When laser processing in the laser processing device 20 is completed, the control device 54 executes a selection process of selecting a destination for the wafer 10 based on the operating status of each blade processing device 30. The control device 54 executes an output process of outputting a destination signal indicating the blade processing device 30 selected in the selection process to the transport device 53. The transfer device 53 to which the transfer destination signal has been input executes a transfer process of transferring the wafer 10 from the laser processing device 20 to the blade processing device 30 indicated by the transfer destination signal.

[0047] The effects of this embodiment will be described. (1) A modified layer 15 is formed in the cutting region 12 of the blade 32. That is, the blade 32 cuts the cutting region 12, a portion of which has been weakened by the modified layer 15. This reduces the resistance acting on the blade 32 as it cuts, thereby reducing wear on the blade 32.

[0048] (2) The modified layer 15 is formed in an area inside the first processing surface 10a and the second processing surface 10b, which makes it difficult for ablation to occur on the first processing surface 10a and the second processing surface 10b due to irradiation with the laser LB.

[0049] (3) The laser processing is used not to cut the wafer 10 but to form the modified layer 15. Therefore, it is possible to reduce the influence of the crystal orientation of the wafer 10 on the processing time and processing quality of the laser processing.

[0050] (4) The modified layer 15 is formed without protruding from the cutting region 12. As a result, even if a crack occurs inside the modified layer 15 due to cutting, the crack is likely to remain within the cutting region 12.

[0051] (5) In the dicing method, when the modified layer 15 is formed at different positions in the thickness direction (Z direction) of the wafer 10, the proportion of the modified layer 15 in the cutting region 12 can be increased. As a result, wear of the blade 32 can be further reduced. Also, the blade processing speed can be increased.

[0052] (6) In the dicing method, when the modified layer 15 is formed at different positions in the width direction of the blade 32, the proportion of the modified layer 15 in the cutting region 12 can be increased. As a result, wear of the blade 32 can be further reduced. Also, the blade processing speed can be increased.

[0053] (7) In the dicing method, laser processing is performed using a laser LB having a wavelength corresponding to a transmittance whose ratio to the peak transmittance T1, which is the highest transmittance for the wafer 10, is 0.95 or more. This allows the modified layer 15 to be formed efficiently by laser processing, and also increases the laser processing speed.

[0054] (8) In the dicing method, it is preferable to perform laser processing using a laser LB having a wavelength within a range of ±200 nm from the peak wavelength λ1 at which the transmittance to the wafer 10 is highest. This allows the modified layer 15 to be formed efficiently by laser processing and increases the laser processing speed. It also makes it easier to find a type of laser LB that can efficiently form the modified layer 15.

[0055] (9) When the wafer 10 is a silicon carbide wafer, the modified layer 15 can be efficiently formed on the wafer 10 by setting the wavelength of the laser LB to be not less than 500 nm and not more than 1200 nm.

[0056] (10) When the wafer 10 is a silicon carbide wafer, the modified layer 15 can be formed on the wafer 10 more efficiently by setting the wavelength of the laser LB to be 700 nm or more and 900 nm or less.

[0057] (11) The laser LB is a pulsed laser. This allows the modified layer 15 to be formed intermittently along the dicing line 11 simply by moving the work table 21 and the laser irradiation unit 22 relative to each other in the X and Y directions. In addition, the energy required for laser processing can be reduced.

[0058] (12) The laser processing conditions are set so that the width of the modified layer 15 in the Z direction is 30 to 50 μm. This increases the degree of freedom in determining the thickness of the wafer 10 that allows the modified layer 15 to be formed at different positions in the Z direction.

[0059] (13) Wafer 10 is a silicon carbide wafer having a first processing surface 10a and a second processing surface 10b opposite to first processing surface 10a, to which dicing tape 16 is attached. First processing surface 10a is an Si surface, and second processing surface 10b is a C surface. Blade 32 rotates in the direction in which blade 32 penetrates wafer 10 from second processing surface 10b.

[0060] Here, in blade processing, wafer chipping occurs due to cracks occurring near the processing surface in a direction different from the direction of blade processing, and is more likely to occur on the processing surface where the blade exits the wafer than on the processing surface where the blade enters the wafer. Furthermore, in silicon carbide wafers, due to the crystal orientation, cracks in a direction different from the direction of blade processing are more likely to occur on the C-plane than on the Si-plane. In this regard, according to the above-described configuration, the second processing surface 10b, which is the processing surface to which the dicing tape 16 is attached and the processing surface where the blade 32 enters the wafer 10, is the C-plane. This makes it less likely for chipping to occur on the C-plane, where cracking is likely to occur, and further increases the blade processing speed.

[0061] (14) According to the above-described dicing method, both the laser processing speed and the blade processing speed can be increased, thereby shortening the processing time for dicing the wafer 10 using laser processing and cutting.

[0062] (15) The dicing system 50 includes a laser processing device 20 that performs laser processing on the wafer 10, a blade processing device 30 that performs cutting processing on the laser-processed wafer 10 using a blade 32 to cut the wafer 10, a transport device 53 that transports the wafer 10 from the laser processing device 20 to the blade processing device 30, and a control device 54 that controls the transport of the wafer 10 by the transport device 53. The laser processing device 20 irradiates the interior of the wafer 10 with a laser LB and forms a modified layer 15 in a cutting region 12 by the blade 32, which is an area inside the edge surface of the wafer 10 in the thickness direction. The control device 54 selects a destination of the laser-processed wafer 10 from among the multiple blade processing devices 30 depending on the operating status of the multiple blade processing devices 30.

[0063] According to this configuration, a plurality of blade processing devices 30 are associated with one laser processing device 20. Therefore, it is possible to shorten the waiting time after the completion of laser processing until the cutting processing of the wafer 10 starts. As a result, it is possible to increase the cycle time for dicing the wafer 10.

[0064] This embodiment can be modified as follows: This embodiment and the following modifications can be combined and implemented within the scope of technical compatibility. When the wafer 10 is a silicon carbide wafer, the first processing surface 10a may be a C-plane and the second processing surface 10b may be a Si-plane.

[0065] The two modified layers 15 formed at different positions in the Z direction do not have to be aligned linearly in the Z direction. That is, the two modified layers 15 may be formed at different positions in at least one of the X direction and the Y direction.

[0066] The two modified layers 15 formed at different positions in the Y direction do not have to be aligned linearly in the Y direction. That is, the two modified layers 15 may be formed at different positions in at least one of the X direction and the Z direction.

[0067] The wavelength of the laser LB is not limited to the above-mentioned wavelengths as long as it can form the modified layer 15. Furthermore, the laser LB is not limited to a pulsed laser, and may be a CW (Continuous wave) laser.

[0068] The modified layer 15 may be formed inside both the first processing surface 10a and the second processing surface 10b in the cutting region 12. Therefore, the modified layer 15 may partially protrude from the cutting region 12 in the Y direction. [Explanation of symbols]

[0069] P...focusing point, 10...wafer, 10a...first processing surface, 10b...second processing surface, 11...dicing line, 12...cutting area, 15...modified layer, 16...dicing tape, 20...laser processing device, 21...work table, 21...blade, 22...laser irradiation unit, 23...laser emission unit, 24...condensing lens, 30...blade processing device, 31...chuck table, 32...blade, 33...spindle, 50...dicing system, 53...conveying device, 54...control device, 100...wafer, 100b...rear surface, 101...blade, 102...modified layer.

Claims

1. a laser processing step of performing laser processing on the wafer; a blade processing step of cutting the wafer after the laser processing using a blade, thereby cutting the wafer, In the laser processing step, a laser is irradiated onto the inside of the wafer, and a modified layer is formed in the region cut by the blade, which is inside the end face in the thickness direction of the wafer. Dicing method.

2. The modified layer is formed without extending beyond the cut area. The dicing method according to claim 1 .

3. In the laser processing step, the modified layer is formed at a plurality of positions in the thickness direction of the wafer.

3. The dicing method according to claim 1 or 2.

4. In the laser processing step, the modified layer is formed at a plurality of positions in the width direction of the blade.

3. The dicing method according to claim 1 or 2.

5. In the laser processing step, the laser processing is performed using a laser having a wavelength corresponding to a transmittance in which the ratio of the transmittance to the wafer's highest peak transmittance is 0.95 or more. The dicing method according to claim 1 .

6. In the laser processing step, the laser processing is performed using a laser having a wavelength within a range of ±200 nm from the peak wavelength at which the transmittance for the wafer is highest. The dicing method according to claim 5.

7. a laser processing device for performing laser processing on a wafer; a blade processing device that performs cutting processing using a blade on the wafer after the laser processing to cut the wafer; a transfer device that transfers the wafer from the laser processing device to the blade processing device; a control device that controls the transfer of the wafer by the transfer device, the laser processing device irradiates a laser beam into the inside of the wafer, and forms a modified layer in a region cut by the blade, which is inside an end face of the wafer in a thickness direction; A plurality of the blade processing devices are provided, The control device selects a destination of the wafer after the laser processing from among the plurality of blade processing devices according to the driving status of the plurality of blade processing devices. Dicing system.

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