Substrate manufacturing method and processing apparatus

Abstract

To improve productivity and throughput when manufacturing a plurality of substrates from a workpiece such as an ingot.SOLUTION: A substrate manufacturing method includes: a separation step of manufacturing a first substrate and a first thinned workpiece by separating the workpiece; and a setting step of setting a second target depth by referring to a substrate-side feedback amount calculated by subtracting the thickness of the first substrate at the time when it is determined that the remaining amount of a first altered layer on a first peeled surface side of the first substrate has become equal to or less than a threshold value from the first target depth, and to a predetermined target thickness.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a substrate manufacturing method for manufacturing a plurality of substrates from a workpiece that includes a first surface and a second surface located opposite the first surface, and whose initial thickness, which is the distance between a first reference point included on the first surface and a second reference point on the second surface located opposite the first reference point, is known in advance, and a processing apparatus for manufacturing the plurality of substrates from this workpiece. [Background technology]

[0002] Semiconductor device chips are generally manufactured using substrates made of single crystal material such as silicon (Si), silicon carbide (SiC), or gallium nitride (GaN), for example, by cutting the substrate using a wire saw from an ingot that includes a first surface and a second surface opposite the first surface.

[0003] However, when cutting a substrate from an ingot using a wire saw, the cutting width is relatively large, at around 300 μm. Furthermore, the surface of the substrate cut in this way has minute irregularities, and the substrate is curved overall (warped). Therefore, when using this substrate to manufacture chips, the surface of the substrate must be flattened by lapping, etching, and / or polishing.

[0004] In this case, only about two-thirds of the total ingot is used as the substrate for chip production. In other words, about one-third of the total ingot is discarded during cutting of the substrate from the ingot and flattening of the substrate surface. Therefore, productivity is low when manufacturing substrates using a wire saw in this way.

[0005] In view of this, a method for manufacturing a substrate has been proposed in which a laser beam having a wavelength that is transmitted through the ingot material is used to manufacture a substrate from the ingot (see, for example, Patent Document 1). Specifically, in this method, first, the ingot and the focal point are moved relatively while the laser beam is irradiated onto the ingot so that the focal point where the laser beam is focused is positioned at a target depth from the first surface.

[0006] This forms a layer (altered layer) inside the ingot where the crystal structure of the material is disrupted, and cracks propagate from this altered layer. Then, in this method, an external force is applied to the ingot to further propagate the cracks until the ingot is separated. As a result, a substrate including a first surface and a separation surface located opposite the first surface, and a thinned ingot including a second surface and a separation surface located opposite the second surface, are produced.

[0007] When the substrate and thinned ingot are manufactured in this manner, a part of the affected layer remains on the separation surface side of the substrate, and the remaining part of the affected layer remains on the separation target surface side of the thinned ingot. In addition, the separation surface of the substrate and the separation target surface of the thinned ingot often have an uneven shape that reflects the distribution of cracks that have propagated inside the ingot.

[0008] Therefore, in this case, the peeling surface side of the substrate is often processed (e.g., ground) to remove and flatten the affected layer remaining on the peeling surface side, and the peeling surface side of the thinned ingot is often processed to remove and flatten the affected layer remaining on the peeling surface side. Furthermore, by repeating this method, multiple substrates can be produced from the ingot (specifically, the ingot is gradually thinned each time this method is repeated). [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-111143 Summary of the Invention [Problem to be solved by the invention]

[0010] In the above-described method, even if the ingot is irradiated with a laser beam so that the focal point is positioned at a target depth from the first surface, the actual depth of the focal point from the first surface may deviate from the target depth depending on the amount of impurities contained in the ingot, etc. Similarly, the thickness of the affected layer formed inside the ingot may also vary depending on the amount of impurities, etc.

[0011] Furthermore, when multiple substrates are produced from an ingot as described above without changing the target depth, the difference between the target depth and the actual depth and / or the thickness of the affected layer formed inside the ingot may vary between the first surface and the second surface of the ingot. That is, even if the target depth is the same when producing the first substrate from the ingot and when producing substrates from an ingot that has been thinned by being used to produce multiple substrates, the difference between the target depth and the thickness of the affected layer will not necessarily be the same.

[0012] Therefore, when manufacturing a plurality of substrates from an ingot as described above, the target depth is often set to be excessively larger than the target thickness of the substrate (for example, the final thickness of the substrate used to manufacture chips). This makes it possible to manufacture substrates having the desired target thickness from the ingot even when the actual depth of the focal point from the first surface is shallower than the target depth and / or the affected layer is thick.

[0013] However, if the actual depth of the focal point from the first surface is deeper than the target depth and / or the affected layer is thin, the proportion of the amount of material discarded when manufacturing a substrate having the target thickness relative to the total amount of the ingot increases, i.e., productivity decreases. Furthermore, in this case, the time required for processing the substrates manufactured by separating the ingot (e.g., grinding to make the substrates have the target thickness) increases, i.e., throughput decreases.

[0014] In view of these circumstances, an object of the present invention is to improve productivity and throughput when manufacturing a plurality of substrates from a workpiece such as an ingot. [Means for solving the problem]

[0015] According to one aspect of the present invention, there is provided a method for manufacturing a plurality of substrates from a workpiece including a first surface and a second surface located opposite to the first surface, and having an initial thickness that is known in advance, the initial thickness being the distance between a first reference point included in the first surface and a second reference point on the second surface located opposite to the first reference point, the method comprising: irradiating the workpiece from the first surface with a laser beam having a wavelength that passes through a material of the workpiece; and moving the workpiece and the focal point relative to each other so that the focal point at which the laser beam is focused passes through a point located at a first target depth from the first reference point. a first separating step of separating the workpiece using a first deteriorated layer formed inside the workpiece as a separation starting point to produce a first substrate including the first surface and a first peeled surface located opposite the first surface, with a portion of the first deteriorated layer remaining on the first peeled surface side, and a first thinned workpiece including the second surface and a first peeled surface located opposite the second surface, with a remainder of the first deteriorated layer remaining on the first peeled surface side; a processing step of processing the first substrate after the first separating step to remove the first deteriorated layer remaining on the first peeled surface side; and a setting step of setting a second target depth with reference to a substrate-side feedback amount calculated by subtracting from the first target depth a thickness obtained by measuring a distance between the first reference point and a third reference point on the first peeled surface opposite to the first reference point at a time when it is determined that the remaining amount of the first affected layer on the first peeled surface side has become equal to or less than a threshold value, and a target thickness previously set as the distance between the first reference point and the third reference point; and after the setting step, irradiating the laser beam onto the first workpiece to be thinned from the first peeled surface side. and by relatively moving the first workpiece to be thinned and the light focusing point so that the light focusing point passes from a fourth reference point on the first peeled surface, which is located on the opposite side of the second reference point of the first workpiece, to a point located at the second target depth, the first workpiece is separated using a second deteriorated layer formed inside the first workpiece as a separation starting point, thereby forming a second substrate including the first peeled surface and a second peeled surface located on the opposite side of the first peeled surface, and a second substrate having a part of the second deteriorated layer remaining on the second peeled surface side, and the second surface and the second peeled surface located on the opposite side of the second surface,and a second separation step of manufacturing a second thinned workpiece in which a remainder of the second affected layer remains on the second peeled surface side.

[0016] In this substrate manufacturing method, the processing step preferably includes a grinding step of grinding the first release surface side of the first substrate until it is determined that the remaining amount of the first altered layer on the first release surface side is equal to or less than the threshold value. In this case, the remaining amount of the first altered layer on the first release surface side is preferably determined based on an image formed by imaging the first release surface, either in parallel with or after interrupting the grinding of the first release surface side of the first substrate. Furthermore, the processing step preferably further includes a finish grinding step, after the grinding step, of finish grinding the first release surface side of the first substrate to thin the first substrate by a predetermined finish grinding amount. In addition, the processing step preferably further includes a polishing step, after the finish grinding step, of polishing the first release surface side of the first substrate to thin the first substrate by a predetermined polishing amount.

[0017] According to another aspect of the present invention, there is provided a method for manufacturing a plurality of substrates from a workpiece including a first surface and a second surface located opposite to the first surface, and having an initial thickness that is known in advance, the initial thickness being the distance between a first reference point included in the first surface and a second reference point on the second surface located opposite to the first reference point, the method comprising: irradiating the workpiece from the first surface with a laser beam having a wavelength that passes through a material of the workpiece; and moving the workpiece and the focal point relative to each other so that the focal point at which the laser beam is focused passes through a point located at a first target depth from the first reference point. a first separating step of separating the workpiece using a first deteriorated layer formed inside the workpiece as a separation starting point to produce a first substrate including the first surface and a first peeled surface located opposite the first surface, with a part of the first deteriorated layer remaining on the first peeled surface side, and a first thinned workpiece including the second surface and a first peeled surface located opposite the second surface, with a remainder of the first deteriorated layer remaining on the first peeled surface side; a processing step of processing the first thinned workpiece after the first separating step so as to remove the first deteriorated layer remaining on the first peeled surface side; a thickness obtained by measuring a distance between the second reference point and a fourth reference point on the first peeled surface located on the opposite side of the second reference point at a time when it is determined that the remaining amount of the first deteriorated layer on the first peeled surface has become equal to or less than a threshold value after the processing step, and subtracting the first target depth from the initial thickness; and a feedback amount of the thinned workpiece side calculated by subtracting the first target depth from the initial thickness; and a distance between the first reference point and a third reference point on the first peeled surface located on the opposite side of the first reference point at a time when it is determined that the remaining amount of the first deteriorated layer on the first peeled surface has become equal to or less than the threshold value after the processing step. a setting step of setting a second target depth by referring to a preset target thickness; and after the setting step, a step of irradiating the laser beam onto the first workpiece from the first peeled surface side, and then relatively moving the first workpiece and the focal point so that the focal point passes through a point located from the fourth reference point of the first workpiece to the second target depth, thereby separating the first workpiece from the first peeled surface using a second deteriorated layer formed inside the first workpiece as a separation starting point, thereby forming the first peeled surface and a second peeled surface located opposite the first peeled surface;and a second separation step of producing a second substrate in which a portion of the second affected layer remains on the second peeling surface side, and a second thinned workpiece in which the second substrate includes the second surface and a second peeled surface located on the opposite side of the second surface, and the remainder of the second affected layer remains on the second peeled surface side.

[0018] In this substrate manufacturing method, the processing step preferably includes a grinding step in which the first surface side of the first thinned workpiece is ground until it is determined that the remaining amount of the first deteriorated layer on the first surface side is equal to or less than the threshold value. In this case, the grinding step preferably determines the remaining amount of the first deteriorated layer on the first surface side based on an image formed by imaging the first surface, either in parallel with or after grinding the first surface side of the first thinned workpiece. Furthermore, the processing step preferably further includes a finish grinding step after the grinding step in which the first surface side of the first thinned workpiece is finish-ground to thin the first thinned workpiece by a predetermined finish grinding amount. In addition, the processing step preferably further includes a polishing step after the finish grinding step in which the first surface side of the first thinned workpiece is polished to thin the first thinned workpiece by a predetermined polishing amount.

[0019] According to yet another aspect of the present invention, there is provided a processing apparatus for producing a plurality of substrates from a workpiece including a first surface and a second surface located opposite to the first surface, and for which an initial thickness, which is a distance between a first reference point included in the first surface and a second reference point located opposite to the first reference point, is known in advance, the processing apparatus comprising: a laser beam irradiation unit for irradiating the workpiece from the first surface with a laser beam having a wavelength that transmits through the material of the workpiece, and relatively moving the workpiece and the focusing point so that the focusing point at which the laser beam is focused passes through a point located at a target depth from the first reference point, thereby forming an affected layer inside the workpiece; a separation unit for separating the workpiece using the affected layer as a separation starting point, thereby producing a substrate including the first surface and a peeled surface located opposite to the first surface, with a part of the affected layer remaining on the peeled surface side; and a thinned workpiece including the second surface and a peeled surface located opposite to the second surface, with the remainder of the affected layer remaining on the peeled surface side; a processor that, when a substrate-side feedback amount calculated by subtracting the thickness obtained by measuring the distance between the first reference point and the third reference point at the time when it is determined that the remaining amount of the altered layer on the peeled surface side has become equal to or less than the threshold value, from the target depth, stores the substrate-side feedback amount in the memory instead of the margin amount, if the substrate-side feedback amount differs from the margin amount.

[0020] In this processing apparatus, the processing unit preferably includes a grinding unit for grinding the release surface side of the substrate until it is determined that the remaining amount of the first deteriorated layer on the release surface side is equal to or less than the threshold value. In this case, the processing unit preferably further includes an imaging unit for forming an image by imaging the release surface while grinding the substrate or while interrupting the grinding, and the processor preferably identifies the remaining amount of the deteriorated layer on the release surface side of the substrate based on the image. Furthermore, the memory preferably further stores a predetermined finish grinding amount, and the processing unit preferably further includes a finish grinding unit for finish grinding the release surface side of the substrate so as to thin the ground substrate by the finish grinding amount. In addition, the memory preferably further stores a predetermined polishing amount, and the processing unit preferably further includes a polishing unit for polishing the release surface side of the substrate so as to thin the finish-ground substrate by the polishing amount.

[0021] According to yet another aspect of the present invention, there is provided a processing apparatus for manufacturing a plurality of substrates from a workpiece including a first surface and a second surface located opposite to the first surface, and having a previously known initial thickness, the initial thickness being the distance between a first reference point included in the first surface and a second reference point located opposite to the first reference point, the processing apparatus including: irradiating the workpiece with a laser beam having a wavelength that transmits through the material of the workpiece from the first surface side, and positioning the workpiece and the focal point such that the focal point at which the laser beam is focused passes through a point located at a target depth from the first reference point; a laser beam irradiation unit for forming an altered layer inside the workpiece by moving the laser beam irradiation unit relatively; a separation unit for separating the workpiece using the altered layer as a separation starting point to produce a thinned workpiece including a substrate having the first surface and a peeling surface located opposite the first surface, with a part of the altered layer remaining on the peeling surface side, and the second surface and a surface to be peeled located opposite the second surface, with a remainder of the altered layer remaining on the surface to be peeled; and a separation unit for removing the altered layer remaining on the surface to be peeled, a processor that, when a feedback amount calculated by subtracting the target depth and the thickness obtained by measuring the distance between the second reference point and a fourth reference point on the surface to be peeled that is located opposite the second reference point at the time when it is determined that the remaining amount of the deteriorated layer on the surface to be peeled has become equal to or less than the threshold value, from the initial thickness, stores the feedback amount in the memory instead of the margin amount.

[0022] In this processing device, the processing unit preferably includes a grinding unit for grinding the peeled surface side of the thinned workpiece until it is determined that the remaining amount of the altered layer on the peeled surface side is equal to or less than the threshold value. In this case, the processing unit preferably further includes an imaging unit for forming an image by imaging the peeled surface, either in parallel with or after interrupting the grinding of the thinned workpiece, and the processor preferably determines the remaining amount of the altered layer on the peeled surface side of the thinned workpiece based on the image. Furthermore, the memory preferably further stores a predetermined finish grinding amount, and the processing unit preferably further includes a finish grinding unit for finish grinding the peeled surface side of the thinned workpiece so as to thin the ground workpiece by the finish grinding amount. In addition, the memory preferably further stores a predetermined polishing amount, and the processing unit preferably further includes a polishing unit for polishing the peeled surface side of the thinned workpiece so as to thin the finish-ground thinned workpiece by the polishing amount. [Effects of the Invention]

[0023] In the present invention, the target depth (second target depth) can be set by referring to the feedback amount calculated using the thickness, etc., obtained by measuring the substrate (first substrate) or thinned workpiece (first thinned workpiece) at the time when it is determined that the remaining amount of the affected layer has become below the threshold value, and the target thickness.

[0024] In this case, the second altered layer can be formed inside the first thinned workpiece so that the thickness of the second substrate at the time when it is determined that the remaining amount of the altered layer (second altered layer) remaining on the peeled surface (second peeled surface) of the newly manufactured substrate (second substrate) has fallen below a threshold value is, for example, roughly the same as the target thickness or slightly thicker than that.

[0025] Therefore, in the present invention, the proportion of the amount of waste generated in the production of a second substrate having a target thickness relative to the total amount of the first thinned workpiece is reduced, i.e., productivity is improved, and the time required for processing the second substrate is reduced, i.e., throughput is improved. [Brief explanation of the drawings]

[0026] [Figure 1] FIG. 1(A) is a perspective view that schematically shows an example of an ingot, and FIG. 1(B) is a side view that schematically shows the ingot shown in FIG. 1(A). [Figure 2] FIG. 2 is a flow chart schematically illustrating an example of a substrate manufacturing method for manufacturing a plurality of substrates from an ingot. [Figure 3] FIG. 3 is a flow chart showing a schematic example of a separation step including a plurality of sub-steps. [Figure 4] FIG. 4(A) is a perspective view that schematically shows the affected layer forming step, and FIG. 4(B) is a partially enlarged cross-sectional view that schematically shows the affected layer forming step. [Figure 5] 5(A) and 5(B) are each a partial cross-sectional side view that schematically shows the external force applying step. [Figure 6] FIG. 6 is a perspective view schematically showing an example of a grinding device used in the processing step. [Figure 7] FIG. 7 is a diagram schematically showing a vertical cross section of a chuck table provided in a grinding device. [Figure 8] FIG. 8 is a diagram schematically showing the upper surface of a chuck table provided in the grinding device. [Figure 9] 9(A) and 9(B) are partial cross-sectional side views that schematically show how the peeled surface side of the substrate is ground to remove the affected layer remaining on the peeled surface side and to flatten it. [Figure 10] Figure 10(A) is a side view schematically showing a substrate from which the affected layer remaining on the separation surface has been removed and flattened, and Figure 10(B) is a side view schematically showing a thinned ingot from which the affected layer remaining on the separation surface has been removed and flattened. [Figure 11] FIG. 11 is a partial cross-sectional side view that schematically shows an example of a grinding apparatus provided with an imaging unit having a structure different from the imaging units provided in the grinding apparatuses shown in FIGS. [Figure 12] Figure 12(A) is a partial cross-sectional side view that schematically shows an example of an imaging-capable grinding device in which the imaging space is filled with liquid, and Figure 12(B) is a partial cross-sectional side view that schematically shows how the peeled surface side of the substrate is ground in the grinding device shown in Figure 12(A) to remove any altered layer remaining on the peeled surface side and to flatten it. [Figure 13] Figure 13(A) is a partially cross-sectional side view that schematically shows another example of an imaging-capable grinding device in which the imaging space is filled with liquid, and Figure 13(B) is a partially cross-sectional side view that schematically shows how the peeled surface side of the substrate is ground in the grinding device shown in Figure 13(A) to remove any altered layer remaining on the peeled surface side and to flatten it. [Figure 14] FIG. 14 is a flow chart schematically illustrating an example of a processing step including a plurality of sub-steps. [Figure 15] FIG. 15 is a partial cross-sectional side view schematically showing the state of the polishing step. [Figure 16] Figures 16(A) and 16(B) are partial cross-sectional side views each showing a schematic diagram of an external force application step performed in a separation device having a structure different from that of the separation device shown in Figures 5(A) and 5(B). [Figure 17] FIG. 17 is a block diagram illustrating an example of a processing device. DETAILED DESCRIPTION OF THE INVENTION

[0027]

[0023] An embodiment of the present invention will be described with reference to the accompanying drawings. Fig. 1(A) is a perspective view schematically showing an example of an ingot, and Fig. 1(B) is a side view schematically showing the ingot shown in Fig. 1(A). The ingot 11 shown in Fig. 1(A) and Fig. 1(B) is made of, for example, a single crystal of SiC and has a cylindrical shape including a first surface (front surface) 11a and a second surface (back surface) 11b that are generally parallel.

[0028] This ingot 11 is manufactured by epitaxial growth. In order to reduce lattice defects formed inside the ingot 11, the ingot 11 is manufactured so that the c-axis 11c of SiC is slightly tilted with respect to a perpendicular line 11d to the first surface 11a and the second surface 11b. For example, the angle (off angle) α between the c-axis 11c and the perpendicular line 11d is 1° to 6° (typically 4°).

[0029] Furthermore, a flat portion indicating the crystal orientation of SiC, i.e., an orientation flat 13, is formed on the side surface of the ingot 11. The orientation flat 13 is formed so as to be perpendicular to the intersection line where a plane parallel to the c-plane 11e of SiC intersects with the first surface 11a or the second surface 11b.

[0030] Note that ingot 11 may be made of a single crystal of a substance other than SiC (for example, Si, GaN, LT, or LN). In addition to orientation flat 13, another orientation flat may be formed on the side surface of ingot 11, or a notch may be formed instead of orientation flat 13 to indicate the crystal orientation of the material constituting ingot 11.

[0031] 2 is a flowchart schematically illustrating an example of a substrate manufacturing method for manufacturing a plurality of substrates from an ingot 11, which serves as a workpiece. In this method, first, the initial thickness of the ingot 11 is determined (determining step S1). In this determining step S1, the initial thickness T0 is determined, for example, by measuring the distance between a first reference point P1 included on the first surface 11a and a second reference point P2 on the second surface 11b located opposite the first reference point P1 (see FIG. 1(B)).

[0032] The distance is measured using a manual or automatic measuring device. The distance is measured, for example, by directly comparing the distance with a reference (e.g., a ruler) (so-called direct measurement). Alternatively, the distance may be derived by measuring the position (e.g., height) of the first reference point P1 and the position (e.g., height) of the second reference point P2 and then calculating the difference between the two (so-called indirect measurement).

[0033] After the grasping step S1, the ingot 11 is separated to produce a substrate and an ingot (thinned ingot) thinner than the ingot 11 (separation step S2). This separation step S2 includes, for example, a plurality of substeps.

[0034] 3 is a flow chart showing an example of the separation step S2 including a plurality of sub-steps. In this separation step S2, first, an affected layer is formed inside the ingot 11 so as to be positioned at a target depth (first target depth) from the first surface 11a (affected layer forming step S21).

[0035] Fig. 4(A) is a perspective view that schematically shows the affected layer forming step S21, and Fig. 4(B) is a partially enlarged cross-sectional view that schematically shows the affected layer forming step S21. Note that the direction indicated by arrow X1 (X1 direction) and the direction indicated by arrow Y1 (Y1 direction) shown in Fig. 4(A) and Fig. 4(B) are directions that are perpendicular to each other on a horizontal plane, and the direction indicated by arrow Z1 (Z1 direction) is a direction (vertical direction) that is perpendicular to both the X1 direction and the Y1 direction.

[0036] This affected layer forming step S21 is performed in a laser beam irradiation device 2. The laser beam irradiation device 2 includes a chuck table 4. The chuck table 4 has a circular upper surface (holding surface), and a porous plate (not shown) is exposed on this holding surface. Furthermore, the porous plate is in communication with a suction source (not shown), such as an ejector, via a flow path or the like formed inside the chuck table 4.

[0037] When the suction source is operated, a suction force acts on the space near the holding surface of the chuck table 4. Therefore, when the suction source is operated with the ingot 11 placed on the holding surface of the chuck table 122, the ingot 11 is held on the holding surface of the chuck table 122.

[0038] The chuck table 4 is also connected to a rotation mechanism (not shown). This rotation mechanism includes, for example, a pulley and a motor. When the rotation mechanism operates, the chuck table 4 rotates around a rotation axis that passes through the center of the holding surface and is aligned in the Z1 direction. For example, the rotation mechanism rotates the chuck table 4 so that the orientation flat 13 of the ingot 11 held on the holding surface of the chuck table 4 is parallel to the Y1 direction.

[0039] A laser head 6 is provided above the chuck table 4. This laser head 6 is provided at the tip of a cylindrical housing 8 extending along the Y1 direction. The laser head 6 houses an optical system such as a condenser lens and a mirror, and the housing 8 houses an optical system such as a mirror and / or a lens.

[0040] The base end of the housing 8 is connected to a movement mechanism (not shown). This movement mechanism includes, for example, a ball screw and a motor for rotating the screw shaft of the ball screw. When the movement mechanism is operated, the housing 8 and the laser head 6 move along the X1 direction, Y1 direction, and / or Z1 direction.

[0041] Furthermore, the laser beam irradiation device 2 is provided with a laser oscillator (not shown) containing, for example, Nd:YAG or the like as a laser medium. This laser oscillator generates a pulsed laser beam LB having a wavelength (e.g., 1030 nm or 1064 nm) that is transparent to the material of the ingot 11. The output (power) of the laser beam LB is then adjusted by an attenuator (not shown), and then emitted directly downward from the laser head 6 via an optical system housed in the housing 8 and the laser head 6.

[0042] Additionally, a camera 10 capable of capturing an image of the area directly below is provided on the side of the housing 8. The camera 10 includes a light source such as an LED (Light Emitting Diode), an objective lens, and an imaging element such as a CCD (Charge Coupled Device) image sensor or a CMOS (Complementary Metal Oxide Semiconductor) image sensor.

[0043] When performing the affected layer forming step S21 in the laser beam irradiation device 2, first, the ingot 11 is placed on the holding surface of the chuck table 4 with the first surface 11a facing upward. Next, the suction source is operated so that the ingot 11 is held on the holding surface of the chuck table 4. Next, the camera 10 is operated so as to capture an image of the ingot 11.

[0044] Next, with reference to the image formed by this imaging, the rotation mechanism rotates the chuck table 4 so that the orientation flat 13 is parallel to the Y1 direction, for example. Next, the movement mechanism moves the laser head 6 along the X1 direction and / or the Y1 direction so that a region of the ingot 11 near one end in the Y1 direction is positioned in the X1 direction as seen from the laser head 6 in a plan view.

[0045] Next, the movement mechanism moves the laser head 6 along the Z1 direction so that the focal point at which the laser beam LB emitted from the laser head 6 is focused is positioned at a first target depth from the first surface 11a of the ingot 11. Next, while emitting the laser beam LB from the laser head 6, the movement mechanism moves the laser head 6 along the X1 direction so that the focal point passes through the ingot 11 in a plan view.

[0046] That is, the laser beam LB is irradiated onto the ingot 11 with its scanning direction perpendicular to the orientation flat 13. As a result, an affected layer (first affected layer) 15 in which the crystalline structure of the material is disturbed is formed inside the ingot 11, centered on the focal point where the laser beam LB is focused. Furthermore, when the affected layer 15 is formed inside the ingot 11, the volume of the ingot 11 expands, causing internal stress in the ingot 11.

[0047] If the internal stress is large, cracks 17 propagate from the affected layer 15 mainly along the c-plane 11e, thereby relieving the internal stress. In the affected layer forming step S21, the laser beam irradiation conditions (e.g., its output) are set so as to generate an internal stress that does not cause cracks 17 to propagate from the affected layer 15 (see FIG. 4(A)). Alternatively, in the affected layer forming step S21, the laser beam irradiation conditions may be set so as to generate an internal stress that causes cracks 17 to propagate from the affected layer 15 (see FIG. 4(B)).

[0048] For example, from the viewpoint of reducing the amount of affected layer 15 remaining in the substrate and thinned ingot produced by separating ingot 11, it is preferable to prevent cracks 17 from extending from affected layer 15 by, for example, relatively reducing the output of the laser beam. On the other hand, from the viewpoint of facilitating separation of ingot 11 in external force application step S22, which will be described later, it is preferable to allow cracks 17 to extend from affected layer 15 by, for example, relatively increasing the output of the laser beam.

[0049] Next, the movement mechanism moves the laser head 6 along the Y1 direction so that, in a plan view, the laser head 6 is positioned in the X1 direction when viewed from a region of the ingot 11 that is slightly inside the region that has already been irradiated with the laser beam LB. Next, the direction opposite to the X1 direction is set as the scanning direction of the laser beam LB, and the laser beam LB is irradiated onto the ingot 11 as described above.

[0050] As a result, a new affected layer 15 is formed inside the ingot 11 so as to be aligned parallel to the existing affected layer 15. Furthermore, if the internal stress generated in the ingot 11 due to the formation of the new affected layer 15 is large, cracks 17 mainly along the c-plane 11e will also extend from this affected layer 15. Furthermore, if the internal stress is large enough that cracks 17a extending along the c-plane extending from each of a pair of affected layers 15 aligned parallel to each other approach each other, cracks 17b will be generated that extend to intersect with the c-plane so as to connect the cracks 17a extending along the adjacent c-planes (see FIG. 4(B)).

[0051] Furthermore, relative movement (specifically, movement of the laser head 6) between the ingot 11 along the Y1 direction and the position where the focal point of the laser beam LB is formed, and irradiation of the ingot 11 with the laser beam LB in the X1 direction or the opposite direction as the scanning direction of the laser beam LB are alternately repeated.

[0052] Then, when the laser beam LB is irradiated onto the region of the ingot 11 near the other end in the Y1 direction, the repetition of the above-mentioned operations is terminated. As a result, multiple rows of affected layers 15 are formed inside the ingot 11, each extending perpendicular to the orientation flat 13. Alternatively, as a result, multiple rows of affected layers 15 and cracks 17 extending from each affected layer 15 are formed inside the ingot 11.

[0053] After the affected layer forming step S21, an external force is applied to the ingot 11 so as to extend the cracks 17 originating from the affected layer 15 (external force applying step S22). Figures 5(A) and 5(B) are partial cross-sectional side views each showing a schematic view of the external force applying step S22.

[0054] This external force application step S22 is performed in the separating apparatus 12. The separating apparatus 12 includes a chuck table 14. The chuck table 14 has a circular upper surface (holding surface), and a porous plate (not shown) is exposed on this holding surface. Furthermore, the porous plate is in communication with a lower suction source (not shown), such as an ejector, via a flow path or the like formed inside the chuck table 14.

[0055] When the lower suction source is operated, a suction force acts on the space near the holding surface of the chuck table 14. Therefore, when the lower suction source is operated with the ingot 11 placed on the holding surface of the chuck table 14, the ingot 11 is held on the holding surface of the chuck table 14.

[0056] A suction plate 16 is provided above the chuck table 14. A plurality of suction ports are formed in the lower surface of the suction plate 16, and each suction port is connected to an upper suction source (not shown), such as a vacuum pump, via a suction path formed inside the suction plate 16. When the upper suction source is operated, a suction force acts on the space near the lower surface of the suction plate 16.

[0057] The lower end of a support shaft 18 is fixed to the upper surface of the suction plate 16, and an elevation mechanism (not shown) is connected to the upper end of the support shaft 18. This elevation mechanism includes, for example, a ball screw and a motor for rotating the screw shaft of the ball screw. When the elevation mechanism is operated, the support shaft 18 and the suction plate 16 move up and down.

[0058] When performing the external force application step S22 in the separation device 12, first, the ingot 11 having the affected layer 15 formed therein is placed on the holding surface of the chuck table 14 with the first surface 11a facing upward, with the chuck table 14 and the suction plate 16 sufficiently spaced apart. Next, the lower suction source is operated so that the ingot 11 is held on the holding surface of the chuck table 14.

[0059] Next, the lifting mechanism lowers the suction plate 16 so that the lower surface of the suction plate 16 contacts the first surface 11a of the ingot 11 (see FIG. 5(A)). Next, the upper suction source is operated so that the first surface 11a side of the ingot 11 is sucked upward. Next, the lifting mechanism raises the suction plate 16 so that the suction plate 16 is separated from the chuck table 14 (see FIG. 5(B)).

[0060] In this case, an external force is applied to the ingot 11 such that the first surface 11a side and the second surface 11b side of the ingot 11 are separated from each other. As a result, new cracks 17 extend from the affected layer 15 and / or existing cracks 17 extend further. As a result, the ingot 11 is separated so as to cleave with the affected layer 15 as the separation starting point.

[0061] As a result, a substrate (first substrate) 19 is produced in which a portion of the affected layer 15 remains on a peeled surface (first peeled surface) 19a located opposite the first surface 11a, and a thinned ingot (first thinned ingot) 21 is produced in which the remaining portion of the affected layer 15 remains on a peeled surface (first peeled surface) 21a located opposite the second surface 11b. Note that each of the peeled surface 19a and the peeled surface 21a often has an uneven shape with a certain degree of periodicity.

[0062] This uneven shape reflects the distribution of cracks 17 that have propagated inside ingot 11. Therefore, in each of the peeled surface 19a and the peeled surface 21a, cracks 17a extending along the c-plane are formed, exposing c-plane 11e, and in each of the peeled surface 19a and the peeled surface 21a, cracks 17b extending to intersect with the c-plane are formed, exposing a mixture of various crystal planes.

[0063] After the separation step S2, the substrate 19 is processed to remove the affected layer 15 remaining on the peeled surface 19a side, and the thinned ingot 21 is processed to remove the affected layer 15 remaining on the peeled surface 21a side (processing step S3). Figure 6 is a perspective view schematically showing an example of a grinding device used in the processing step S3.

[0064] 6, the direction indicated by the arrow X2 (X2 direction) and the direction indicated by the arrow Y2 (Y2 direction) are directions that are perpendicular to each other on a horizontal plane. Specifically, the X2 direction is the backward direction, and the Y2 direction is the rightward direction. The direction indicated by the arrow Z2 (Z2 direction) is a direction (upward) that is perpendicular to both the X2 direction and the Y2 direction.

[0065] 6 has a base 22 that supports each component. A rectangular parallelepiped recess 22a extending along the X2 axis direction is formed on the upper surface of the base 22. A chuck table 24 for holding the substrate 19 and / or the thinned ingot 21 is provided inside the recess 22a.

[0066] The chuck table 24 is movable between a position (loading / unloading position) where the substrate 19 or thinned ingot 21 is loaded onto and unloaded from its holding surface, and a position (grinding position) where the substrate 19 and / or thinned ingot 21 held on the holding surface is ground. Fig. 6 shows the grinding apparatus 20 with the chuck table 24 positioned at the loading / unloading position. The grinding position is located in the X2 direction as viewed from the loading / unloading position, i.e., behind it.

[0067] Fig. 7 is a diagram schematically showing a vertical cross section of the chuck table 24 positioned at the grinding position. Note that in Fig. 7, some components of the grinding device 20 are shown as blocks. Fig. 8 is a diagram schematically showing the upper surface of the chuck table 24 positioned at the grinding position.

[0068] The chuck table 24 has a disk-shaped frame 26 made of, for example, ceramics. The frame 26 has a disk-shaped bottom wall 26a and a cylindrical side wall 26b extending from the outer periphery of the bottom wall 26a. That is, a disk-shaped recess defined by the bottom wall 26a and the side wall 26b is formed on the upper surface of the frame 26.

[0069] A disk-shaped porous plate 28 made of porous ceramics or the like is fixed in this recess. The upper surface of the side wall 26b of the frame 26 and the upper surface of the porous plate 28 have a shape corresponding to the side surface of a cone, and function as a holding surface when holding the substrate 19 or the thinned ingot 21.

[0070] In addition, a flow path 26c is formed in the bottom wall 26a, which opens at the bottom surface of the recess and penetrates the bottom wall 26a. The flow path 26c communicates with the suction source 32a via the valve 30a and with the fluid supply source 32b via the valve 30b.

[0071] The suction source 32a includes, for example, an ejector, etc. The fluid supply source 32b includes, for example, a tank for storing high-pressure gas, a filter for removing foreign matter mixed in the gas supplied from the tank, and a regulator for adjusting the pressure of the gas supplied from the tank.

[0072] The chuck table 24 is connected to a motor 34 via, for example, a pulley (not shown) and a belt (not shown) wound around the pulley. When the motor 34 is operated, the chuck table 24 rotates, for example, clockwise in a plan view (along the direction of arrow A1 shown in FIG. 8) around a rotation axis that is a straight line passing through the center of the holding surface of the chuck table 24.

[0073] An encoder 36 is provided near the chuck table 24. The encoder 36 includes, for example, a light source that irradiates light (e.g., visible light) toward a scale formed on the lower surface of the bottom wall 26a of the frame 26 of the chuck table 24, and a light-receiving element that converts the light reflected by the lower surface of the bottom wall 26a into an electrical signal. The encoder 36 then detects the rotation angle of the chuck table 24 based on the electrical signal.

[0074] The chuck table 24 is supported by a tilt adjustment mechanism (not shown) via bearings (not shown), a table base (not shown), etc. This tilt adjustment mechanism includes, for example, two movable shafts and one fixed shaft that are arranged at approximately equal angular intervals along the circumferential direction of the chuck table 24. When at least one of the two movable shafts partially raises or lowers the table base and the chuck table 24, the tilt of the rotation axis of the chuck table 24 is adjusted.

[0075] An X2-direction movement mechanism (not shown) is provided inside a recess 22a formed on the upper surface of the base 22. This X2-direction movement mechanism includes, for example, a ball screw and a motor for rotating the screw shaft of the ball screw. When this X2-direction movement mechanism is operated, the chuck table 24 moves between the carry-in / out position and the grinding position.

[0076] A rectangular parallelepiped table cover 38 is provided around the periphery of the chuck table 24 so that the holding surface of the chuck table 24 is exposed. The width (length along the Y2 direction) of this table cover 38 is approximately equal to the width of the recess 22a formed in the upper surface of the base 22. In addition, dustproof and drip-proof covers 40 that are extendable and contractible along the X2 direction are provided in front and behind the table cover 38.

[0077] A processing chamber cover 42 is provided on the upper surface of the base 22 to surround a space (processing chamber) where grinding of the substrate 19 or the thinned ingot 21 is performed. The processing chamber cover 42 has a rectangular top plate 44 whose width (length along the Y2 direction) is larger than that of the recess 22a. The top plate 44 overlaps with the rear side of the recess 22a in a plan view.

[0078] The top plate 44 has a circular opening 44a formed therein, the center of which is located on the rear side of the top plate 44 and which exposes the center and rear end of the holding surface of the chuck table 24 positioned in the grinding position in a plan view.

[0079] The opening 44a is formed to allow the grinding wheel 88, which will be described later, to enter and exit the machining chamber. Specifically, the opening 44a is formed in the top plate 44 so that its center in a plan view coincides with the center of the grinding wheel 88 and its diameter is larger than the outer diameter of the grinding wheel 88.

[0080] The upper end of a front side plate 46 is fixed to the underside of the front end of the top plate 44. A rectangular opening 46a is formed in the front side plate 46, which allows the chuck table 24 holding the substrate 19 or the thinned ingot 21 to enter and exit the processing chamber. In other words, the front side plate 46 has a gate-like shape, specifically, a shape in which the lower side of the portion overlapping with the recess 22a is cut out.

[0081] The upper end of a rear plate 48, the upper end of a left plate 50, and the upper end of a right plate 52 are fixed to the lower side of the rear end, the lower side of the left end, and the lower side of the right end of the top plate 44, respectively. Each of the rear plate 48, the left plate 50, and the right plate 52 has a rectangular shape. The lower ends of the front plate 46, the rear plate 48, the left plate 50, and the right plate 52 are fixed to the upper surface of the base 22.

[0082] Furthermore, the processing chamber cover 42 includes a partition plate 54 for dividing the processing chamber into a space (grinding space) GS where grinding of the substrate 19 or thinned ingot 21 is performed and a space (imaging space) IS where imaging of the ground substrate 19 or thinned ingot 21 is performed.

[0083] The partition plate 54 extends in the Y2 direction and has approximately the same length as the front plate 46 and the rear plate 48. The upper end, left end, and right end of the partition plate 54 are fixed to the lower side of a portion of the top plate 44 slightly forward of the opening 44a, the inside of the upper part of the left plate 50, and the inside of the upper part of the right plate 52, respectively.

[0084] The imaging space IS is provided with an imaging unit 56 for imaging the peeled surface 19a of the substrate 19 or the peeled surface 21a of the thinned ingot 21 held on the holding surface of the chuck table 24. The imaging unit 56 is located forward when viewed from the center of the holding surface of the chuck table 24 positioned at the grinding position, and has a rectangular top plate 56a that overlaps with the front side of the holding surface in a plan view.

[0085] A top plate 56a of the imaging unit 56 is supported on the processing chamber cover 42 via four supports 58, each of which is provided so as to hang down from the top plate 44 of the processing chamber cover 42. A camera 56b is provided in the center of the top plate 56a of the imaging unit 56, with its objective lens facing downward.

[0086] Furthermore, light sources 56c are provided below each of the four ends of the top plate 56a. Each light source 56c can emit light (for example, visible light) obliquely downward so as to illuminate a position overlapping with the top plate 56a in a plan view.

[0087] Furthermore, a fluid spraying unit (specifically, an air curtain) 60 is provided in the opposite direction to the rotation direction of the chuck table 24 (the direction of arrow A1 shown in FIG. 8) as viewed from the camera 56b of the imaging unit 56. The air curtain 60 is supported by the processing chamber cover 42 via a plurality of supports 62, each of which is provided so as to protrude forward from the partition plate 54.

[0088] The air curtain 60 extends radially along the holding surface of the chuck table 24 positioned at the grinding position in a plan view, and can spray air directly below it. That is, the air curtain 60 can spray air toward the area of ​​the holding surface of the chuck table 24 that has entered the imaging space IS from the grinding space GS.

[0089] 6, a quadrangular pillar-shaped support structure 64 is provided in an area located behind the recess 22a on the upper surface of the base 22. A grinding unit 66 is provided in front of the support structure 64. The grinding unit 66 has a Z2-direction movement mechanism 68 provided on the front surface of the support structure 64.

[0090] The Z2-direction movement mechanism 68 includes a pair of guide rails 70 each extending along the Z2 direction. A slider (not shown) is provided on the front side of each of the pair of guide rails 70 so as to be slidable along the Z2 direction. The front end of the slider is fixed to the rear surface side of a rectangular parallelepiped lift plate 72.

[0091] Furthermore, a screw shaft 74 extending along the Z2 direction is disposed between the pair of guide rails 70. A motor 76 for rotating the screw shaft 74 is connected to the upper end of the screw shaft 74. A nut (not shown) that houses balls that circulate in response to the rotation of the screw shaft 74 is provided on the outer circumferential surface of the screw shaft 74 on which the threads are formed, thereby forming a ball screw.

[0092] The nut is fixed to the rear side of the lift plate 72. Therefore, when the screw shaft 74 is rotated by the motor 76, the lift plate 72 moves in the Z2 direction together with the nut. A cylindrical support member 78 is fixed to the front side of the lift plate 72.

[0093] A cylindrical housing 80 extending along the Z2 direction is provided inside the support member 78. A spindle 84 is provided inside the housing 80 and is rotatably supported by the housing 80, with its upper end connected to a motor 82 (see FIGS. 7 and 8). The lower end of the spindle 84 is exposed from the housing 80 and is fixed to a disk-shaped wheel mount 86.

[0094] An annular grinding wheel 88 having an outer diameter roughly equal to the diameter of the wheel mount 86 is attached to the underside of the wheel mount 86 using a fixing member (not shown) such as a bolt. When the motor 82 is operated, the wheel mount 86 and grinding wheel 88 rotate together with the spindle 84, with a rotation axis that is a straight line along the Z2 direction.

[0095] The grinding wheel 88 has a plurality of grinding stones 88a and a wheel base 88b having a lower surface on which the plurality of grinding stones 88a are arranged discretely in an annular shape. When the motor 82 is operated, the wheel mount 86 and the grinding wheel 88 rotate, for example, clockwise in a plan view (along the direction of arrow A2 shown in FIG. 8) around a rotation axis that is a straight line along the Z2 direction.

[0096] Each of the grinding wheels 88a contains a binder such as a vitrified bond or a resin bond, and abrasive grains such as diamond or cBN dispersed in the binder. The wheel base 88b is made of, for example, an alloy such as stainless steel or a metal such as aluminum.

[0097] Furthermore, a grinding fluid supply unit 90 is provided near the grinding wheel 88. This grinding fluid supply unit 90 has a pipe 92 inserted into a through-hole formed in the rear side plate 48 of the machining chamber cover 42. The base end (one end) of the pipe 92 is connected to a grinding fluid supply source (not shown). Note that this grinding fluid supply source includes, for example, a tank for storing a liquid (grinding fluid) such as water, and a pump for sending the grinding fluid from the tank toward the pipe 92.

[0098] A nozzle 94 is provided at the tip (other end) of the piping 92. When the grinding fluid supply unit 90 (specifically, the pump of the grinding fluid supply source) is operated, the grinding fluid is supplied from the grinding fluid supply source through the piping 92 and the nozzle 94 toward the rear side of the holding surface of the chuck table 24 positioned at the grinding position.

[0099] In addition, the grinding apparatus 20 may be provided with a contact or non-contact thickness gauge for measuring the thickness of the substrate 19 or thinned ingot 21 held on the holding surface of the chuck table 24. Specifically, this thickness gauge can measure the distance between a first reference point P1 included on the first surface 11a of the substrate 19 and a third reference point on the peeled surface 19a located on the opposite side of the first reference point P1, or the distance between a second reference point P2 included on the second surface 11b of the thinned ingot 21 and a fourth reference point on the peeled surface 21a located on the opposite side of the second reference point P2.

[0100] In the grinding device 20, for example, the peeled surface 19a side of the substrate 19 is ground so as to remove the affected layer 15 remaining on the peeled surface 19a side and to flatten it. Figures 9(A) and 9(B) are partial cross-sectional side views each showing a schematic view of this grinding process. When this grinding is performed, the chuck table 24 is first positioned at the load / unload position.

[0101] Next, the substrate 19 is placed on the holding surface of the chuck table 24 with the peeled surface 19a facing upward. Next, the suction source 32a is operated and the valve 30a is opened. This causes a suction force to act on the substrate 19 from the chuck table 24. As a result, the substrate 19 is held on the holding surface of the chuck table 24 with the peeled surface 19a exposed.

[0102] Next, the chuck table 24 is positioned at the grinding position (see FIG. 9(A)). Next, while both the chuck table 24 and the grinding wheel 88 are rotating, the grinding wheel 88 is lowered so that the grinding stones 88a come into contact with the peeled surface 19a of the substrate 19. Just before this contact, the supply of grinding fluid L from the nozzle 94 of the grinding fluid supply unit 90, the spraying of air from the air curtain 60, and the imaging by the camera 56b with light emitted from each light source 56c of the imaging unit 56 are started.

[0103] This allows grinding of the peeled surface 19a side of the substrate 19 while grinding fluid L is supplied to the contact interface (processing point) between the multiple grinding wheels 88a and the peeled surface 19a of the substrate 19, and imaging of the peeled surface 19a of the substrate 19 while preventing the grinding fluid L from entering between the camera 56b and the peeled surface 19a of the substrate 19, to be performed in parallel.

[0104] This grinding is continued until it is determined that the remaining amount of the affected layer 15 on the peeled surface 19a side is equal to or less than a threshold value. For example, when making this determination, first, the remaining amount of the affected layer 15 on the peeled surface 19a side (e.g., the area ratio of the affected layer 15 on the peeled surface 19a) is identified based on an image formed by imaging the peeled surface 19a of the substrate 19. Then, when it is determined that this remaining amount is equal to or less than a threshold value (e.g., 0), this grinding is terminated.

[0105] This image may be subjected to various processes, such as rotation according to the rotation angle of the chuck table 24 detected by the encoder 36, or extraction using a Fourier transform of a pattern corresponding to the altered layer 15 formed at a predetermined period.

[0106] Furthermore, in the grinding device 20, for example, after or before grinding the peeling surface 19a side of the substrate 19, the peeling surface 21a side of the thinned ingot 21 is ground so as to remove and flatten the affected layer 15 remaining on the peeling surface 21a side. Alternatively, the thinned ingot 21 may be ground in another grinding device having the same or similar structure as the grinding device 20. Note that grinding of the peeling surface 21a side of the thinned ingot 21 may be performed in the same manner as, for example, grinding of the peeling surface 19a side of the substrate 19 described above.

[0107] For example, from the viewpoint of reducing the number of devices required to perform processing step S3, it is preferable to grind the thinned ingot 21 in the grinding device 20 after or before grinding the peeled surface 19a side of the substrate 19. On the other hand, from the viewpoint of reducing the time required for processing step S3, i.e., improving throughput, it is preferable to grind the peeled surface 21a side of the thinned ingot 21 in another grinding device having the same or similar structure as the grinding device 20.

[0108] 10(A) is a side view showing the substrate 19 after the altered layer 15 remaining on the peeled surface 19a side has been removed and the substrate 19 has been flattened, and FIG. 10(B) is a side view showing the thinned ingot 21 after the altered layer 15 remaining on the peeled surface 21a side has been removed and the substrate 19 has been flattened. S1 and the thickness T of the thinned ingot 21 I1 is understood.

[0109] Specifically, the thickness T of the substrate 19 is determined by measuring the distance between a first reference point P1 included in the first surface 11a and a third reference point P3 on the peeled surface 19a located on the opposite side of the first reference point P1. S1 In addition, the thickness T of the thinned ingot 21 is obtained by measuring the distance between the second reference point P2 included in the second surface 11b and the fourth reference point P4 on the surface 21a to be peeled, which is located on the opposite side of the second reference point P2. I1 The measurement of these intervals is performed, for example, in the same manner as in the above-described determination step S1.

[0110] and the thickness T of the substrate 19 S1 The target thickness is T T If the thickness is more than the above, the substrate 19 is further processed as necessary and used for a desired purpose (for example, for manufacturing chips). I1 If the thickness is greater than the thickness required to produce two substrates (step S4: NO), this thinned ingot 21 is used to produce a new substrate (second substrate) and an ingot (second thinned ingot) that is thinner than the thinned ingot 21.

[0111] The thickness required to manufacture two substrates is, for example, the target thickness T T and the thickness T of the substrate 19 S1 and the thickness T of the thinned ingot 21 I1 The thickness is calculated by subtracting the thickness T from the initial thickness T. The second substrate and the second thinned ingot are manufactured by performing the above-described separation step S2 (i.e., the affected layer forming step S21 and the external force applying step S22) using the thinned ingot 21 as the base material instead of the ingot 11.

[0112] 2, before the separation step S2 and the processing step S3 are performed again, the target depth in the affected layer formation step S21 is updated based on known information. Specifically, in this method, the target thickness T T With reference to the above, a target depth (second target depth) of the focal point where the laser beam LB is focused from the surface 21a to be peeled of the thinned ingot 21 is set (setting step S5).

[0113] For example, when the thickness obtained by measuring the substrate 19 is used in the setting step S5, the thickness T of the substrate 19 is S1 The feedback amount (substrate side feedback amount F S ) is calculated (see equation (1) below).

number

[0114] In this case, the second target depth D2 is, for example, the substrate side feedback amount F S and target thickness T T The value is set to be the sum of (see equation (2) below).

number

[0115] Alternatively, in this case, the second target depth D2 is the substrate side feedback amount F S and target thickness T T and a predetermined buffer amount B (see equation (3) below).

number

[0116] In addition, when the thickness obtained by measuring the thinned ingot 21 is used in the setting step S5, the thickness T I1 The feedback amount (thinned ingot side feedback amount F) is calculated by subtracting the first target depth D1 from the initial thickness T0. TI ) is calculated (see equation (4) below).

number

[0117] In this case, the second target depth D2 is, for example, the thinned ingot side feedback amount F TI and target thickness T T The value is set to be the sum of (see equation (5) below).

number

[0118] Alternatively, in this case, the second target depth D2 is, for example, the thinned ingot side feedback amount F TI and target thickness T T and the buffer amount B (see equation (6) below).

number

[0119] In addition, if it is assumed that the thickness of the affected layer 15 remaining on the peeled surface 19a side of the substrate 19 is k times (k is a positive real number other than 1) the thickness of the affected layer 15 remaining on the peeled surface 21a side of the thinned ingot 21, the second target depth D2 is TI k times the target thickness T T Alternatively, the value may be set to be the sum of (see Equation (7) below).

number

[0120] Alternatively, if such a situation is assumed, the second target depth D2 is set to the thinned ingot side feedback amount F TI k times the target thickness T T and the buffer amount B may be set to a value obtained by adding the buffer amount B.

number

[0121] Furthermore, if the first actual depth deviates from the first target depth D1, there is a high probability that the actual depth from the surface 21a of the thinned ingot 21 to be peeled of the focal point where the laser beam LB is focused will also deviate from the second target depth D2 by the same amount.

[0122] Therefore, even if the first actual depth deviates from the first target depth D1, by setting the second target depth D2 according to the above formula (2), (5), or (7), a second damaged layer can be formed inside the thinned ingot 21 so that the thickness of the second substrate at the time when it is determined that the remaining amount of the second damaged layer on the second peeled surface side of the second substrate has become below the threshold value is approximately equal to the target thickness.

[0123] Even in such a case, by setting the second target depth D2 as in the above formula (3), (6), or (8), the second damaged layer can be formed inside the thinned ingot 21 so that the thickness of the second substrate at the time when it is determined that the remaining amount of the second damaged layer on the second peeled surface side of the second substrate has become equal to or less than the threshold value is approximately equal to the thickness calculated by adding the target thickness and the buffer amount B.

[0124] In the substrate manufacturing method shown in FIG. 2, a feedback amount (substrate-side feedback amount F) is calculated using the thickness or the like obtained by measuring the substrate 19 or the thinned ingot 21 at the time when it is determined that the remaining amount of the affected layer 15 has become equal to or less than the threshold value. S or the feedback amount F on the thinned ingot side TI ) and the target thickness T T The second target depth D2 can be set by referring to the above.

[0125] In this case, the thickness of the second substrate at the time when it is determined that the remaining amount of the second deteriorated layer on the second peeled surface side of the second substrate is equal to or less than the threshold value is set to, for example, a target thickness T T or target thickness T T The affected layer can be formed inside the thinned ingot 21 so that the value of the thickness of the thinned ingot 21 is approximately equal to the sum of the amount of the buffer amount B and the amount of the buffer amount C.

[0126] Therefore, in this method, the target thickness T T This reduces the proportion of the amount of waste generated in the manufacture of the substrate having the above structure to the total amount of thinned ingot 21, i.e., improves productivity, and also reduces the time required for processing the second substrate, i.e., improves throughput.

[0127] The above-described content is one aspect of the present invention, and the present invention is not limited to the above-described content. For example, in the present invention, it is sufficient that at least one of the peeled surface 19a side of the substrate 19 and the peeled surface 21a side of the thinned ingot 21 is processed in the processing step S3, and it is not necessary to process both of them.

[0128] However, when only the substrate 19 is processed in the processing step S3, the thinned ingot side feedback amount F TI Therefore, in this case, it is impossible to calculate the substrate side feedback amount F S The second target depth D2 is set by referring to the above equations (2) and (3).

[0129] Similarly, when only the thinned ingot 21 is processed in the processing step S3, the substrate-side feedback amount F S Therefore, in this case, it is impossible to calculate the thinned ingot side feedback amount F TI The second target depth D2 is set by referring to the above formulas (5) to (8).

[0130] Furthermore, if the thinned ingot 21 is not processed in the processing step S3, multiple rows of altered layers 15 will remain on the peeled surface 21a side, and the thinned ingot 21 will have an uneven shape on the peeled surface 21a (specifically, a shape including an area where the c-plane 11e is exposed and an area where various crystal planes are exposed in a mixed manner), and will be used to manufacture the second substrate and the second thinned ingot.

[0131] If the optical path of the laser beam LB overlaps with the multiple rows of affected layers 15 or with the region of the peeled surface 21a where various crystal planes are exposed, it may be difficult to focus the laser beam LB at the desired target depth. Therefore, if the thinned ingot 21 is not processed in the processing step S3, it is preferable to perform the affected layer forming step S21 so that the optical path of the laser beam LB overlaps with the gaps between the multiple rows of affected layers 15 and the region of the peeled surface 21a where the c-plane 11e is exposed.

[0132] Furthermore, in the present invention, it is only necessary to remove the affected layer 15 remaining on at least one of the delamination surface 19a side of the substrate 19 and the delamination surface 21a side of the thinned ingot 21 in the processing step S3, and they do not have to be flattened. That is, in the present invention, the processing step S3 may be performed so as to produce a substrate 19 having an uneven delamination surface 19a and / or a thinned ingot 21 having an uneven delamination surface 21a.

[0133] For example, in processing step S3, at least one of the peeled surface 19a side of substrate 19 and the peeled surface 21a side of thinned ingot 21 may be ground so that the area near the center is thinner than the area near the periphery. This processing step S3 is performed in the same manner as the processing step S3 described above, except that the inclination of chuck table 24 is adjusted so that the center of the holding surface is positioned higher than a point other than the center included in the holding surface.

[0134] Furthermore, in the present invention, the image of the peeled surface 19a or the peeled surface 21a may be taken not in parallel with grinding of the peeled surface 19a side of the substrate 19 or the peeled surface 21a side of the thinned ingot 21, but after the grinding is interrupted. In this case, the remaining amount of the affected layer 15 based on the image formed by the image capture and the determination of whether the identified remaining amount has become equal to or less than a threshold value may be performed while the grinding is interrupted. In this case, if the remaining amount of the affected layer 15 exceeds the threshold value, the grinding may be resumed, and if not, the grinding may be terminated.

[0135] In addition, in the present invention, the remaining amount of the altered layer 15 on the peeled surface 19a side of the substrate 19 and / or the peeled surface 21a side of the thinned ingot 21 may be determined using other analytical methods such as Raman spectroscopy or spectroscopic ellipsometry, without relying on the image formed by imaging.

[0136] In the present invention, the processing step S3 may be performed using a grinding apparatus provided with an imaging unit having a structure different from that of the imaging unit 56. Figure 11 is a partial cross-sectional side view schematically showing an example of a grinding apparatus provided with an imaging unit having a structure different from that of the imaging unit 56 (specifically, the imaging unit 98 shown in Figure 11, the imaging unit 102 shown in Figures 12(A) and 12(B), or the imaging unit 106 shown in Figures 13(A) and 13(B)).

[0137] 11 has the same structure as the grinding apparatus 20, except that the imaging unit 56 is replaced with an imaging unit 98. The imaging unit 98 has a top plate 98a and a camera 98b similar to the top plate 56a and the camera 56b of the imaging unit 56.

[0138] Furthermore, the imaging unit 98 has an annular light source 98c that is provided on the underside of the top plate 98a so as to surround the underside of the camera 98b and that is capable of emitting light downward, and mirrors 98d that are provided on the underside of each of the four ends of the top plate 98a. Note that each mirror 98d is generally thinner than each light source 56c included in the imaging unit 56.

[0139] The grinding device 96 is preferable compared to the grinding device 20 in that it can widen the imaging field of the camera 98b. On the other hand, the grinding device 20 is preferable compared to the grinding device 96 in that the shape of the peeled surface 19a of the substrate 19 and / or the peeled surface 21a of the thinned ingot 21 (for example, the periodic uneven shape caused by grinding) is more likely to be reflected in the image formed by the imaging by the camera 98b.

[0140] In addition, in the present invention, the peeled surface 19a of the substrate 19 and / or the peeled surface 21a of the thinned ingot 21 may be imaged with the imaging space IS filled with liquid. Figures 12(A) and 13(A) are partially cross-sectional side views each showing a schematic example of a grinding device capable of imaging in this manner.

[0141] 12(A) has the same structure as grinding apparatus 20, except that imaging unit 56 is replaced with imaging unit 102 and there is no air curtain 60. This imaging unit 102 has a top plate 102a, a camera 102b, and a light source 102c that are similar to top plate 56a, camera 56b, and light source 56c of imaging unit 56.

[0142] Furthermore, the imaging unit 102 has, for example, a rectangular light-transmitting member 102d made of a material (e.g., glass) that transmits light emitted from the light source 102c. The light-transmitting member 102d is located slightly below the light source 102c, and one end thereof is fixed to the lower end of the partition plate 54 of the processing chamber cover 42. Fig. 12(B) is a partial cross-sectional side view that schematically shows how the grinding apparatus 100 grinds the peeled surface 19a side of the substrate 19 so as to remove the affected layer 15 remaining on the peeled surface 19a side and to flatten the surface.

[0143] When grinding the substrate 19 in this manner, while both the chuck table 24 and the grinding wheel 88 are rotating, the grinding wheel 88 is lowered so that the grinding stones 88a come into contact with the peeled surface 19a of the substrate 19. Also, just before this grinding, the supply of grinding fluid L from the nozzle 94 of the grinding fluid supply unit 90 and the image capture by the camera 102b with light emitted from each light source 102c of the imaging unit 102 are started.

[0144] This allows grinding of the peeled surface 19a side of the substrate 19 when grinding fluid L is supplied to the processing point, and imaging of the peeled surface 19a side of the substrate 19 when grinding fluid L has entered between the translucent member 102d and the peeled surface 19a of the substrate 19, i.e., when the imaging space IS is filled with grinding fluid L, to be performed in parallel.

[0145] Furthermore, in the grinding apparatus 100, in addition to or instead of grinding the peeled surface 19a of the substrate 19, the peeled surface 21a side of the thinned ingot 21 may be ground so as to remove and flatten the affected layer 15 remaining on the peeled surface 21a side. Grinding of the peeled surface 21a side of the thinned ingot 21 in the grinding apparatus 100 may be performed, for example, in the same manner as the grinding of the peeled surface 19a side of the substrate 19 described above.

[0146] The grinding apparatus 100 does not include any components corresponding to the air curtain 60 provided in the grinding apparatus 20. Therefore, the grinding apparatus 100 is preferable in that it has a simpler structure and can be manufactured at lower cost than the grinding apparatus 20, and mist generated by injecting air into the grinding fluid L does not get mixed into the imaging space IS and reduce the accuracy of the image formed by imaging by the camera 102b.

[0147] On the other hand, the grinding apparatus 20 can capture an image of the peeled surface 19a of the substrate 19 or the peeled surface 21a of the thinned ingot 21 without filling the imaging space IS with the grinding fluid L. Therefore, the grinding apparatus 20 is preferable to the grinding apparatus 100 in that it allows for a higher degree of freedom in the grinding conditions (particularly, the supply conditions of the grinding fluid L) when grinding the peeled surface 19a side of the substrate 19 and / or the peeled surface 21a side of the thinned ingot 21.

[0148] 13(A) has a similar structure to grinding apparatus 20, except that imaging unit 56 is replaced with imaging unit 106, and support 58 provided to hang down from top plate 44 is replaced with a longer support 108. This imaging unit 56 has a top plate 106a, a camera 106b, and a light source 106c similar to top plate 56a, camera 56b, and light source 56c of imaging unit 56.

[0149] However, a through hole is formed in the top plate 106a, and the tip of a pipe 106d is connected to the upper surface of the top plate 106a so as to communicate with this through hole. This pipe 106d is inserted into a through hole formed in the top plate 44 of the processing chamber cover 42, and its base end is connected to a water supply source (not shown).

[0150] The water supply source includes, for example, a tank for storing water and a pump for sending water from the tank toward the pipe 106d. Fig. 13(B) is a partial cross-sectional side view schematically showing how the peeled surface 19a side of the substrate 19 is ground in the grinding device 104 to remove and flatten the affected layer 15 remaining on the peeled surface 19a side.

[0151] When grinding the substrate 19 in this manner, while both the chuck table 24 and the grinding wheel 88 are rotating, the grinding wheel 88 is lowered so that the plurality of grinding stones 88a contact the peeled surface 19a of the substrate 19. Immediately before this grinding, the following operations are started: supply of grinding fluid L from the nozzle 94 of the grinding fluid supply unit 90; spraying of air from the air curtain 60; imaging by the camera 106b with light emitted from each light source 106c of the imaging unit 106; and supply of water W from the water supply source via the piping 106d.

[0152] This allows grinding of the peeled surface 19a side of the substrate 19 while grinding fluid L is supplied to the contact interface (processing point) between the multiple grinding wheels 88a and the peeled surface 19a of the substrate 19, and imaging of the peeled surface 19a of the substrate 19 while preventing the grinding fluid L from entering between the camera 106b and the peeled surface 19a of the substrate 19 and supplying water W, i.e., filling the imaging space IS with water W, to be carried out in parallel.

[0153] Furthermore, in the grinding device 104, in addition to or instead of grinding the peeled surface 19a of the substrate 19, the peeled surface 21a side of the thinned ingot 21 may be ground so as to remove and flatten the affected layer 15 remaining on the peeled surface 21a side. Grinding of the peeled surface 21a side of the thinned ingot 21 in the grinding device 104 may be performed, for example, in the same manner as the grinding of the peeled surface 19a side of the substrate 19 described above.

[0154] The grinding device 104 is capable of capturing an image of the peeled surface 19a of the substrate 19 or the peeled surface 21a of the thinned ingot 21 with the imaging space IS filled with water W. Therefore, the grinding device 104 is preferable to the grinding device 20 in that mist generated by spraying air into the grinding fluid L and / or grinding chips generated by grinding do not get mixed into the imaging space IS, thereby preventing a decrease in the accuracy of the image formed by imaging with the camera 106b.

[0155] On the other hand, the grinding apparatus 20 does not include components corresponding to the piping 106d and the water supply source provided in the grinding apparatus 104. Therefore, the grinding apparatus 20 is preferable compared to the grinding apparatus 104 in that its structure is simpler and can be manufactured at lower cost.

[0156] Furthermore, in the present invention, a fluid ejection unit having a structure different from that of the air curtain 60 may be provided. For example, instead of or in addition to the air curtain 60, the fluid ejection unit may include a nozzle capable of ejecting a fluid (e.g., air or water) toward the holding surface of the chuck table 24.

[0157] In the present invention, the processing step S3 may include a plurality of sub-steps. Fig. 14 is a flow chart schematically showing an example of the processing step S3 including a plurality of sub-steps.

[0158] 14, grinding (rough grinding), finish grinding, and polishing are sequentially performed on the peeled surface 19a side of the substrate 19 and the peeled surface 21a side of the thinned ingot 21. In this case, damage that ultimately remains on the peeled surface 19a side of the substrate 19 and the peeled surface 21a side of the thinned ingot 21 can be reduced.

[0159] Specifically, in the processing step S3 shown in FIG. 14, first, the peeling surface 19a side of the substrate 19 is ground until it is determined that the remaining amount of the altered layer 15 on the peeling surface 19a side is below a threshold value, and then the peeling surface 21a side of the thinned ingot 21 is ground until it is determined that the remaining amount of the altered layer 15 on the peeling surface 21a side is below a threshold value (grinding step S31).

[0160] In this grinding step S31, for example, grinding devices 20, 96, 100, and 104 are used. Then, the grinding step S31 is performed, for example, by grinding the peeled surface 19a side of the substrate 19 and grinding the peeled surface 21a side of the thinned ingot 21 as described above.

[0161] The threshold value used for the determination in the grinding step S31 may be set to a value greater than 0. That is, the affected layer 15 remaining on the peeled surface 19a side of the substrate 19 and the peeled surface 21a side of the thinned ingot 21 may not be completely removed in the grinding step S31, but may be removed in the subsequent steps (specifically, the finish grinding step S32 and the polishing step S33, which will be described later).

[0162] Furthermore, in the grinding step S31, each of the peeled surface 19a side of the substrate 19 and the peeled surface 21a side of the thinned ingot 21 may or may not be flattened. For example, in the grinding step S31, each of the peeled surface 19a side of the substrate 19 and the peeled surface 21a side of the thinned ingot 21 may be ground so that the vicinity of the center is thinner than the vicinity of the periphery.

[0163] After the grinding step S31, the peeled surface 19a side of the substrate 19 is finish-ground so as to thin the substrate 19 by a predetermined finish-grinding amount, and the peeled surface 21a side of the thinned ingot 21 is finish-ground so as to thin the thinned ingot 21 by the predetermined finish-grinding amount (finish-grinding step S32). Note that the finish-grinding amount is set to, for example, 0.6 to 0.9 times the buffer amount B.

[0164] In this finish grinding step S32, for example, a grinding wheel (finish grinding wheel) is provided in which the grain size of the abrasive grains contained in the grinding stone 88a of the grinding wheel 88 provided in the grinding device 20, 96, 100, 104 is contained, and a grinding device having a structure similar to that of the grinding device 20, 96, 100, 104 is used, except that the imaging unit 56, 98, 102, 106 is not provided.

[0165] Alternatively, in the finish grinding step S32, the grinding device 20, 96, 100, 104 may be used in which the grinding wheel 88 attached to the lower end of the spindle 84 is replaced with a finish grinding wheel. Then, the finish grinding step S32 is performed, for example, by grinding the peeled surface 19a side of the substrate 19 and grinding the peeled surface 21a side of the thinned ingot 21 as described above.

[0166] In the finish grinding step S32, the peeled surface 19a side of the substrate 19 and the peeled surface 21a side of the thinned ingot 21 may or may not be flattened. For example, in the finish grinding step S32, the peeled surface 19a side of the substrate 19 and the peeled surface 21a side of the thinned ingot 21, which have been ground in the grinding step S31 so that the vicinity of the center is thinner than the vicinity of the periphery, may both be ground so as to be flattened.

[0167] In this case, when finish grinding is started on the peeled surface 19a side of the substrate 19 or the peeled surface 21a side of the thinned ingot 21, only the portion near the periphery is ground by the multiple grinding stones of the finish grinding wheel. Therefore, in this case, each grinding stone that intermittently collides with the portion near the periphery is dressed, making it possible to suppress deterioration of the processing performance of the finish grinding wheel.

[0168] After the finish grinding step S32, the peeled surface 19a side of the substrate 19 is polished so as to thin the substrate 19 by a predetermined polishing amount, and the peeled surface 21a side of the thinned ingot 21 is polished so as to thin the thinned ingot 21 by a predetermined polishing amount (polishing step S33). The polishing amount is set to, for example, 0.1 to 0.4 times the buffer amount B.

[0169] Fig. 15 is a partial cross-sectional side view schematically showing the polishing step S33. Specifically, Fig. 15 shows the polishing of the peeled surface 19a side of the substrate 19 so as to thin the substrate 19 by a predetermined polishing amount.

[0170] This polishing step S33 is performed in a polishing apparatus 110. The polishing apparatus 110 includes a chuck table 112 having a circular holding surface that is approximately parallel to a horizontal plane and that can hold the substrate 19 or thinned ingot 21 on this holding surface.

[0171] The chuck table 112 is connected to a suction source (not shown). This suction source includes, for example, an ejector. When the suction source is operated, a suction force acts on the space near the holding surface of the chuck table 112. Therefore, when the suction source is operated with the substrate 19 or thinned ingot 21 placed on the holding surface, the substrate 19 or thinned ingot 21 is held on the holding surface of the chuck table 112.

[0172] The chuck table 112 is connected to a lower rotation mechanism (not shown). This lower rotation mechanism includes, for example, a pulley and a motor. When the lower rotation mechanism operates, the chuck table 112 rotates around a rotation axis that passes through the center of the holding surface and is aligned in the vertical direction.

[0173] A polishing pad 114 is provided above the chuck table 112. This polishing pad 114 has a disk-shaped base 114a and a disk-shaped polishing layer 114b that is fixed to the underside of this base 114a and has roughly the same diameter as the base 114a. This polishing layer 114b is a fixed abrasive layer with abrasive grains dispersed therein, and is produced, for example, by impregnating a polyester nonwoven fabric with a urethane solution in which abrasive grains are dispersed, and then drying the nonwoven fabric.

[0174] The abrasive grains dispersed inside the polishing layer 114b are made of materials such as SiC, cBN, diamond, or metal oxide particles, etc. The metal oxide particles may be made of silica (SiO2), ceria (CeO2), zirconia (ZrO2), or alumina (Al2O3).

[0175] The polishing pad 114 is mounted on the lower surface of a pad mount 116 having approximately the same diameter as the polishing pad 114. Furthermore, the lower end of a spindle 118 extending vertically is fixed to the center of the upper surface of the pad mount 116, and an upper rotation mechanism (not shown) and an elevation mechanism (not shown) are connected to the upper end of this spindle 118.

[0176] The upper rotation mechanism includes, for example, a motor for rotating the spindle 118. When this upper rotation mechanism is operated, the spindle 118, the pad mount 116, and the polishing pad 114 rotate around a vertical line as a rotation axis. The lifting mechanism includes, for example, a ball screw and a motor for rotating the screw shaft of the ball screw. When this lifting mechanism is operated, the spindle 118, the pad mount 116, and the polishing pad 114 move up and down.

[0177] Additionally, a through hole TH extending vertically is formed in the center of the base 114a and polishing layer 114b of the polishing pad 114, the pad mount 116, and the spindle 118. The through hole TH communicates with a polishing liquid supply source (not shown). The polishing liquid supply source includes, for example, a tank for storing a liquid (polishing liquid) such as water, and a pump for sending the polishing liquid from the tank toward the through hole TH.

[0178] When polishing the peeled surface 19a side of the substrate 19 in the polishing apparatus 110, first, the substrate 19 is placed on the holding surface of the chuck table 112 with the peeled surface 19a facing upward. Next, the suction source is operated so that the substrate 19 is held on the holding surface of the chuck table 112.

[0179] Next, while both the chuck table 112 and the polishing pad 114 are rotating, the polishing pad 114 is lowered so that the polishing layer 114b contacts the peeled surface 19a of the substrate 19. Also, just before this contact, the supply of polishing liquid from the polishing liquid supply source to the through holes TH begins. As a result, the peeled surface 19a side of the substrate 19 is polished with the polishing liquid (not shown) supplied to the contact interface (processing point) between the polishing pad 114 and the peeled surface 19a of the substrate 19.

[0180] In the present invention, in the grinding step S31, the finish grinding step S32, and the polishing step S33, it is sufficient that at least one of the peeled surface 19a side of the substrate 19 or the peeled surface 21a side of the thinned ingot 21 is processed, and it is not necessary to process both of them.

[0181] Furthermore, in the present invention, the affected layer forming step S21 may utilize a laser beam irradiation device having a structure different from that of the laser beam irradiation device 2. For example, the affected layer forming step S21 may be performed in a laser beam irradiation device provided with a movement mechanism for moving the chuck table 4 along the X1 direction, the Y1 direction, and / or the Z1 direction, instead of or in addition to a movement mechanism for moving the laser head 6 and the like along the X1 direction, the Y1 direction, and / or the Z1 direction.

[0182] Alternatively, the affected layer forming step S21 may be performed in a laser beam irradiation device provided with a scanning optical system capable of changing the direction of the laser beam LB emitted from the laser head 6, instead of or in addition to a movement mechanism for moving the laser head 6 or the like along the X1 direction, Y1 direction, and / or Z1 direction. The scanning optical system may include, for example, a galvanometer scanner, an acousto-optical device (AOD), and / or a polygon mirror.

[0183] That is, in the laser beam irradiation device used in the affected layer formation step S21, it is sufficient that the chuck table 4 and the focal point where the laser beam LB is focused can move relatively along each of the X1 direction, Y1 direction, and Z1 direction, and there are no limitations on the structure for this purpose.

[0184] In the present invention, the external force applying step S22 may utilize a separation device having a structure different from that of the separation device 12. Each of Figures 16(A) and 16(B) is a partial cross-sectional side view schematically illustrating the external force applying step S22 performed in a separation device 120 having a structure different from that of the separation device 12.

[0185] The separating device 120 has a circular upper surface (holding surface) on which a porous plate (not shown) is exposed. Furthermore, the porous plate is in communication with a suction source (not shown) such as an ejector via a flow path formed inside the chuck table 122.

[0186] When the suction source is operated, a suction force acts on the space near the holding surface of the chuck table 122. Therefore, when the suction source is operated with the ingot 11 placed on the holding surface of the chuck table 122, the ingot 11 is held on the holding surface of the chuck table 122.

[0187] A disk-shaped support base 124 is provided above the chuck table 122. A plurality of movable members 126 are provided below a portion of the support base 124 near its outer periphery at approximately equal angular intervals along the circumferential direction of the support base 124. Each movable member 126 has a plate-shaped hanging portion 126a extending downward from the support base 124.

[0188] The upper end of hanging portion 126a is connected to an actuator such as an air cylinder built into support base 124, and when this actuator is operated, movable member 126 moves along the radial direction of support base 124. In addition, plate-shaped claw portion 126b is provided on the inner surface of the lower end of hanging portion 126a, extending radially inward of support base 124 and becoming thinner as it approaches the tip.

[0189] Furthermore, the lower end of a support shaft 128 is fixed to the center of the upper surface of the support base 124, and an elevation mechanism (not shown) is connected to the upper end of this support shaft 128. The elevation mechanism includes, for example, a ball screw and a motor for rotating the screw shaft of the ball screw. When this elevation mechanism is operated, the support shaft 128, support base 124, and movable member 126 move up and down.

[0190] When performing the external force application step S22 in the separation device 120, first, the chuck table 122 and the support base 124 are sufficiently separated from each other, and the ingot 11 having the affected layer 15 formed therein is placed on the holding surface of the chuck table 122 with the first surface 11a facing upward. Next, the suction source is operated so that the ingot 11 is held on the holding surface of the chuck table 122.

[0191] Next, the actuator is operated to position each of the multiple movable members 126 radially outward from the support base 124. Next, the lifting mechanism is operated to position the tip of the claw portion 126b of each of the multiple movable members 126 at a height corresponding to the affected layer 15. Next, the actuator is operated to bring the claw portion 126b into contact with the ingot 11. Next, the lifting mechanism is operated to raise the claw portion 126b (see FIG. 16(A)).

[0192] In this case, an external force that separates the first surface 11a side and the second surface 11b side of the ingot 11 is applied to a portion near the outer periphery of the ingot 11. As a result, new cracks 17 extend from the affected layer 15 and / or existing cracks 17 extend further. As a result, the ingot 11 is separated so as to cleave with the affected layer 15 as the separation starting point (see FIG. 16(B)).

[0193] Furthermore, in the present invention, an ultrasonic wave applying step may be performed after the affected layer forming step S21 and before the external force applying step S22, in which ultrasonic waves are applied to the first surface 11a side of the ingot 11. In this case, new cracks 17 extend from the affected layer 15 and / or existing cracks 17 extend further in the ultrasonic wave applying step, which makes it easier to separate the ingot 11 in the external force applying step S22.

[0194] The present invention may also be a processing apparatus for manufacturing a plurality of substrates from an ingot 11. Fig. 17 is a block diagram schematically showing an example of the processing apparatus, specifically, an example of a processing apparatus capable of performing the separating step S2, the processing step S3, and the setting step S5.

[0195] The processing device 130 shown in FIG. 17 includes a laser beam irradiation unit 132, a separating unit 134, a processing unit 136, and a controller 138 for controlling the laser beam irradiation unit 132, the separating unit 134, and the processing unit 136.

[0196] The laser beam irradiation unit 132 has a structure similar to that of the laser beam irradiation device 2 shown in Fig. 4(A), for example. Therefore, the laser beam irradiation unit 132 can form multiple rows of affected layers 15 inside the ingot 11 as described above.

[0197] The separation unit 134 has a structure similar to that of the separation apparatus 12 shown in Figures 5(A) and 5(B) or the separation apparatus 120 shown in Figures 16(A) and 16(B), for example. Therefore, in the separation unit 134, it is possible to separate the ingot 11 by cleaving it using the affected layer 15 as the separation starting point, as described above.

[0198] The processing unit 136 has a grinding section (rough grinding section) 136a for grinding (rough grinding) the peeling surface 19a side of the substrate 19 and the peeled surface 21a side of the thinned ingot 21, a finish grinding section 136b for finish grinding, and a polishing section 136c for polishing.

[0199] 6 and the like, the grinding device 96 shown in Fig. 11, the grinding device 100 shown in Fig. 12(A) and Fig. 12(B), or the grinding device 104 shown in Fig. 13(A) and Fig. 13(B). Therefore, in the grinding device 136a, as described above, it is possible to grind the peeling surface 19a side of the substrate 19 until it is determined that the remaining amount of the affected layer 15 on the peeling surface 19a side has become equal to or less than a threshold value, and to grind the peeling surface 21a side of the thinned ingot 21 until it is determined that the remaining amount of the affected layer 15 on the peeling surface 21a side has become equal to or less than a threshold value.

[0200] Furthermore, the finish grinding unit 136b has a structure similar to that of the grinding devices 20, 96, 100, and 104, except that, for example, the grinding wheel 88 is replaced with the above-described finish grinding wheel, and the imaging units 56, 98, 102, and 106 are not provided. Alternatively, the finish grinding unit 136b may have a structure similar to that of the grinding devices 20, 96, 100, and 104, except that the grinding wheel 88 is replaced with the above-described finish grinding wheel. Therefore, the finish grinding unit 136b can finish grind the peeled surface 19a side of the substrate 19 so as to thin the substrate 19 by a predetermined finish grinding amount, as described above, and can finish grind the peeled surface 21a side of the thinned ingot 21 so as to thin the thinned ingot 21 by a predetermined finish grinding amount.

[0201] Furthermore, the polishing unit 136c has a structure similar to that of the polishing apparatus 110 shown in Fig. 15. Therefore, in the polishing unit 136c, it is possible to polish the peeled surface 19a side of the substrate 19 so as to thin the substrate 19 by a predetermined polishing amount, and to polish the peeled surface 21a side of the thinned ingot 21 so as to thin the thinned ingot 21 by a predetermined polishing amount.

[0202] Each of the grinding unit 136a, the finish grinding unit 136b, and the polishing unit 136c may be provided with a structure for processing (specifically, grinding, finish grinding, or polishing) the peeled surface 19a side of the substrate 19, and a structure for processing the peeled surface 21a side of the thinned ingot 21. Each of the grinding unit 136a, the finish grinding unit 136b, and the polishing unit 136c may be provided with only a structure for processing either the peeled surface 19a side of the substrate 19 or the peeled surface 21a side of the thinned ingot 21.

[0203] Furthermore, at least one of the finish grinding unit 136b and the polishing unit 136c does not have to be provided in the processing unit 136. That is, the processing unit 136 may be configured with only the grinding unit 136a, or may be configured with the grinding unit 136a and either the finish grinding unit 136b or the polishing unit 136c.

[0204] The controller 138 includes a processor 138a and a memory 138b. The processor 138a is configured, for example, by a CPU (Central Processing Unit) etc. The memory 138b is configured, for example, by a volatile memory such as a DRAM (Dynamic Random Access Memory) or an SRAM (Static Random Access Memory) and a non-volatile memory such as an SSD (Solid State Drive) (NAND flash memory) or an HDD (Hard Disk Drive) (magnetic storage device).

[0205] The memory 138b stores data and programs used by the processor 138a. Examples of this data include the above-mentioned threshold value and the target thickness T T When setting the target depth (specifically, the first target depth D1), the target thickness T T and a margin amount M referenced together with the margin amount M. This program may be, for example, a program for performing the substrate manufacturing method shown in FIG.

[0206] The processor 138a reads and executes a program stored in the memory 138b while using the data stored in the memory 138b. For example, the processor 138a reads and executes a program for implementing the substrate manufacturing method shown in FIG. 2 from the memory 138b.

[0207] 2 is performed in the processing apparatus 130, the processor 138a first controls the processing unit 136 to measure the initial thickness T0 of the ingot 11 using, for example, a thickness gauge provided in the grinding section 136a of the processing unit 136, which has a structure similar to that of the grinding apparatuses 20, 96, 100, and 104. In this way, the initial thickness T0 of the ingot 11 is determined.

[0208] Next, the target thickness T stored in the memory 138b is calculated. TThe processor 138a sets the first target depth D1 by referring to the margin amount M and the target thickness T T The first target depth D1 is set to be the sum of the above (see formula (9) below).

number

[0209] Alternatively, the processor 138a may calculate the margin amount M and the target thickness T T The first target depth D1 may be set to a value obtained by adding a predetermined buffer amount B to the first target depth D1 (see the following formula (10)).

number

[0210] Then, the processor 138 a controls the laser beam irradiation unit 132 , the separation unit 134 and the processing unit 136 to produce the substrate 19 and the thinned ingot 21 from the ingot 11 .

[0211] Specifically, the processor 138a controls the laser beam irradiation unit 132 to form multiple rows of affected layers 15 inside the ingot 11, similar to the above-described affected layer forming step S21, and then controls the separation unit 134 to separate the ingot 11, similar to the above-described external force applying step S22. Then, the processor 138a controls the processing unit 136 to process the peeled surface 19a side of the substrate 19 and the peeled surface 21a side of the thinned ingot 21, similar to the above-described processing step S3.

[0212] In addition, when the processor 138a controls the processing unit 136 in this way, the thickness T S1 and the thickness T of the thinned ingot 21 I1The processor 138a controls the processing unit 136 to measure the thickness T of the thinned ingot 21, for example, using the thickness measuring device described above. I1 If is larger than the thickness required to manufacture two substrates, the substrate side feedback amount F S or the feedback amount F on the thinned ingot side TI (see formulas (1) and / or (4) above).

[0213] Furthermore, the calculated substrate side feedback amount F S or the feedback amount F on the thinned ingot side TI If the margin amount M is different from the margin amount M, the processor 138a updates the margin amount M. That is, in this case, the processor 138a updates the substrate-side feedback amount F instead of the margin amount M. S or the feedback amount F on the thinned ingot side TI is stored in memory 138b.

[0214] Then, the processor 138 a controls the laser beam irradiation unit 132 , the separation unit 134 and the processing unit 136 to produce a second substrate and a second thinned ingot from the thinned ingot 21 .

[0215] Specifically, the processor 138a controls the laser beam irradiation unit 132 to form multiple rows of affected layers 15 inside the ingot 11 in the same manner as in the above-described affected layer forming step S21, except that the first target depth D1 is replaced with the second target depth D2 calculated by the above-described formulas (2), (3), and (5) to (8), and then the processor 138a controls the separation unit 134 to separate the ingot 11 in the same manner as in the above-described external force applying step S22. Then, the processor 138a controls the processing unit 136 to process the peeled surface 19a side of the substrate 19 and the peeled surface 21a side of the thinned ingot 21, respectively, in the same manner as in the above-described processing step S3.

[0216] In the processing device 130, each unit (specifically, the laser beam irradiation unit 132, the separation unit 134, and the processing unit 136) may not be controlled by a single controller 138, but a controller may be provided for each unit, and each unit may be controlled by a separate controller.

[0217] The processing unit 130 may further include a thickness measuring device for measuring the initial thickness T0 of the ingot 11 and the thickness T of the substrate 19 in place of or in addition to the thickness measuring device provided in the grinding section 136a of the processing unit 136. S1 or the thickness T of the thinned ingot 21 I1 A measurement unit may be provided for measuring at least one of the above.

[0218] The processing device 130 may also be provided with a transport unit for transporting at least one of the ingot 11, substrate 19 or thinned ingot 21 into or out of any of the laser beam irradiation unit 132, separation unit 134 and processing unit 136.

[0219] In the present invention, substrate 19 may be manufactured using a bare wafer as the workpiece instead of ingot 11. The bare wafer has a thickness that is, for example, two to five times that of the substrate to be manufactured. The bare wafer is manufactured by being separated from ingot 11 by a method similar to the substrate manufacturing method shown in FIG. 2. In this case, substrate 19 can also be expressed as being manufactured by repeating the substrate manufacturing method shown in FIG. 2 twice.

[0220] In the present invention, the substrate 19 may be manufactured using a device wafer, which is manufactured by forming semiconductor devices on one surface of the bare wafer, as a workpiece. In this case, in order to prevent adverse effects on the semiconductor devices, it is preferable that the laser beam LB be irradiated onto the device wafer from the side of the device wafer on which the semiconductor devices are not formed.

[0221] In addition, the structures and methods according to the above-described embodiments can be modified as appropriate without departing from the scope of the present invention. [Explanation of symbols]

[0222] 2: Laser beam irradiation device 4: Chuck table 6: Laser head 8: Housing 10: Camera 11: Ingot (11a: first surface (front surface), 11b: second surface (back surface)) (11c: c-axis, 11d: perpendicular, 11e: c-plane) 12: Separation device 13: Orientation Flat 14: Chuck table 15: Altered layer (first altered layer) 16: Suction plate 17: Crack (17a: Crack extending along the c surface) (17b: Crack extending to intersect with the c-plane) 18: Support shaft 19: Substrate (first substrate) (19a: Release surface (first release surface)) 20: Grinding equipment 21: Thinned ingot (first thinned ingot) (21a: peeled surface (first peeled surface)) 22: Base (22a: recess) 24: Chuck table 26: Frame (26a: bottom wall, 26b: side wall, 26c: flow path) 28: Porous plate 30a, 30b: Valve 32a: Suction source 32b: Fluid supply source 34: Motor 36: Encoder 38: Table cover 40: Dustproof and water-resistant cover 42: Processing chamber cover 44: Top plate (44a: opening) 46: Front plate (46a: opening) 48: Rear side plate 50:Left side board 52: Right side plate 54: Partition board 56: Imaging unit (56a: top plate, 56b: camera, 56c: light source) 58: Support 60: Fluid injection unit (air curtain) 62: Support equipment 64:Support structure 66: Grinding section 68:Z2 direction movement mechanism 70: Guide rail 72: Lifting plate 74: Screw shaft 76: Motor 78: Support member 80: Housing 82: Motor 84: Spindle 86: Wheel mount 88: Grinding wheel (88a: grinding wheel, 88b: wheel base) 90: Grinding fluid supply unit 92: Piping 94: Nozzle 96: Grinding equipment 98: Imaging unit (98a: top plate, 98b: camera, 98c: light source, 98d: mirror) 100: Grinding equipment 102: Imaging unit (102a: top plate, 102b: camera) (102c: light source, 102d: transparent member) 104: Grinding equipment 106: Imaging unit (106a: top plate, 106b: camera) (106c: Light source, 106d: Piping) 108: Support equipment 110: Polishing equipment 112: Chuck table 114: Polishing pad (114a: base, 114b: polishing layer) 116: Pad mount 118:Spindle 120: Separation device 122: Chuck table 124: Support stand 126: Movable member (126a: Drooping part, 126b: Claw part) 128: Support shaft 130: Processing device 132: Laser beam irradiation unit 134: Separation unit 136: Processing unit (136a: Grinding unit (rough grinding unit)) (136b: finish grinding section, 136c: polishing section) 138: Controller (138a: processor, 138b: memory)

Claims

1. A method for manufacturing a substrate, comprising: manufacturing a plurality of substrates from a workpiece including a first surface and a second surface located opposite to the first surface; and having an initial thickness, the initial thickness being a distance between a first reference point included in the first surface and a second reference point on the second surface located opposite to the first reference point, known in advance; a first separation step in which a laser beam having a wavelength that transmits through the material of the workpiece is irradiated onto the workpiece from the first surface side, and the workpiece and the focal point at which the laser beam is focused are moved relatively to one another so that the focal point passes through a point located at a first target depth from the first reference point, thereby separating the workpiece using a first deteriorated layer formed inside the workpiece as a separation starting point, thereby producing a first substrate including the first surface and a first peeled surface located opposite the first surface, with a portion of the first deteriorated layer remaining on the first peeled surface side, and a first peeled surface located opposite the second surface, with a remainder of the first deteriorated layer remaining on the first peeled surface side; a processing step of processing the first substrate after the first separation step so as to remove the first affected layer remaining on the first peeled surface side; a setting step of setting a second target depth by referring to a substrate-side feedback amount calculated by subtracting from the first target depth a thickness obtained by measuring a distance between the first reference point and a third reference point on the first peeled surface located opposite to the first reference point at a time when it is determined that the remaining amount of the first affected layer on the first peeled surface side has become equal to or less than a threshold value after the processing step, and a target thickness that is preset as the distance between the first reference point and the third reference point; a second separation step after the setting step, in which the first workpiece to be thinned and the focal point are relatively moved while the laser beam is irradiated onto the first workpiece from the first surface to be peeled so that the focal point passes from a fourth reference point on the first surface to be peeled, located on the opposite side of the second reference point of the first workpiece, to a point located at the second target depth, thereby separating the first workpiece from a second deteriorated layer formed inside the first workpiece as a separation starting point, to produce a second substrate including the first surface to be peeled and a second surface to be peeled located on the opposite side of the first surface, with a part of the second deteriorated layer remaining on the second surface side, and a second workpiece including the second surface and a second surface to be peeled located on the opposite side of the second surface, with a remainder of the second deteriorated layer remaining on the second surface side; A method for manufacturing a substrate, comprising:

2. 2. The method for manufacturing a substrate according to claim 1, wherein the processing step includes a grinding step of grinding the first peeling surface side of the first substrate until it is determined that the remaining amount of the first altered layer on the first peeling surface side is below the threshold value.

3. 3. The method for manufacturing a substrate according to claim 2, wherein in the grinding step, the remaining amount of the first altered layer on the first peeling surface side is identified based on an image formed by imaging the first peeling surface in parallel with or after interrupting grinding of the first peeling surface side of the first substrate.

4. 4. The method for manufacturing a substrate according to claim 2 or 3, wherein the processing step further includes, after the grinding step, a finish grinding step of finish grinding the first release surface side of the first substrate so as to thin the first substrate by a predetermined finish grinding amount.

5. 5. The method for manufacturing a substrate according to claim 4, wherein the processing step further includes, after the finish grinding step, a polishing step of polishing the first release surface side of the first substrate so as to thin the first substrate by a predetermined polishing amount.

6. A method for manufacturing a substrate, comprising: manufacturing a plurality of substrates from a workpiece including a first surface and a second surface located opposite to the first surface; and having an initial thickness, the initial thickness being a distance between a first reference point included in the first surface and a second reference point on the second surface located opposite to the first reference point, known in advance; a first separation step in which a laser beam having a wavelength that transmits through the material of the workpiece is irradiated onto the workpiece from the first surface side, and the workpiece and the focal point at which the laser beam is focused are moved relatively to one another so that the focal point passes through a point located at a first target depth from the first reference point, thereby separating the workpiece using a first deteriorated layer formed inside the workpiece as a separation starting point, thereby producing a first substrate including the first surface and a first peeled surface located opposite the first surface, with a portion of the first deteriorated layer remaining on the first peeled surface side, and a first peeled surface located opposite the second surface, with a remainder of the first deteriorated layer remaining on the first peeled surface side; a processing step of processing the first thinned workpiece after the first separating step so as to remove the first affected layer remaining on the first peeled surface side; a setting step of setting a second target depth by referring to a feedback amount of the thinned workpiece side calculated by subtracting the thickness obtained by measuring the distance between the second reference point and a fourth reference point on the first peeled surface located opposite the second reference point at the time when it is determined that the remaining amount of the first affected layer on the first peeled surface has become equal to or less than the threshold value and the first target depth from the initial thickness after the processing step, and a target thickness that is preset as the distance between the first reference point and a third reference point on the first peeled surface located opposite the first reference point at the time when it is determined that the remaining amount of the first affected layer on the first peeled surface has become equal to or less than the threshold value; a second separation step after the setting step, in which the first workpiece to be thinned and the focal point are moved relatively to each other while the laser beam is irradiated onto the first workpiece from the first peeled surface side so that the focal point passes through a point located from the fourth reference point on the first workpiece to the second target depth, thereby separating the first workpiece from a second deteriorated layer formed inside the first workpiece as a separation starting point, thereby producing a second substrate including the first peeled surface and a second peeled surface located opposite the first peeled surface, with a part of the second deteriorated layer remaining on the second peeled surface side, and a second workpiece including the second surface and a second peeled surface located opposite the second surface, with a remainder of the second deteriorated layer remaining on the second peeled surface side; A method for manufacturing a substrate, comprising:

7. 7. The method for manufacturing a substrate according to claim 6, wherein the processing step includes a grinding step of grinding the first peeled surface side of the first thinned workpiece until it is determined that the remaining amount of the first altered layer on the first peeled surface side is below the threshold value.

8. 8. The method for manufacturing a substrate described in claim 7, wherein in the grinding step, the remaining amount of the first altered layer on the first peeled surface side is identified based on an image formed by imaging the first peeled surface in parallel with or after interrupting grinding of the first peeled surface side of the first thinned workpiece.

9. 9. The method for manufacturing a substrate according to claim 7 or 8, wherein the processing step further includes, after the grinding step, a finish grinding step of finish grinding the first peeled surface side of the first thinned workpiece so as to thin the first thinned workpiece by a predetermined finish grinding amount.

10. The method for manufacturing a substrate according to claim 9, wherein the processing step further includes, after the finish grinding step, a polishing step of polishing the first peeled surface side of the first thinned workpiece so as to thin the first thinned workpiece by a predetermined polishing amount.

11. A processing apparatus for manufacturing a plurality of substrates from a workpiece including a first surface and a second surface located opposite to the first surface, the initial thickness of which is a distance between a first reference point included in the first surface and a second reference point located opposite to the first reference point, the processing apparatus comprising: a laser beam irradiation unit for forming an altered layer inside the workpiece by irradiating the workpiece from the first surface side with a laser beam having a wavelength that transmits through the material of the workpiece, and relatively moving the workpiece and the focal point where the laser beam is focused so that the focal point passes through a point located at a target depth from the first reference point; a separation unit for separating the workpiece using the deteriorated layer as a separation starting point to produce a substrate including the first surface and a peeled surface located opposite the first surface, with a portion of the deteriorated layer remaining on the peeled surface side, and a thinned workpiece including the second surface and a peeled surface located opposite the second surface, with a remainder of the deteriorated layer remaining on the peeled surface side; a processing unit for processing the substrate so as to remove the altered layer remaining on the peeled surface side; a controller for controlling the laser beam irradiation unit, the separation unit, and the processing unit; The controller a memory for storing the initial thickness, a threshold value for the remaining amount of the altered layer, a target thickness that is preset as the distance between the first reference point and a third reference point on the peeled surface located opposite the first reference point at the time when it is determined that the remaining amount of the altered layer on the peeled surface side has become equal to or less than the threshold value, and a margin amount that is referenced together with the target thickness when setting the target depth; a processor that, when it is determined that the remaining amount of the altered layer on the peeled surface side has become equal to or less than the threshold value, calculates a substrate-side feedback amount by subtracting a thickness obtained by measuring the distance between the first reference point and the third reference point from the target depth, and stores the substrate-side feedback amount in the memory instead of the margin amount, if the substrate-side feedback amount differs from the margin amount; a processing device comprising:

12. The processing apparatus according to claim 11 , wherein the processing unit includes a grinding section for grinding the peeled surface side of the substrate until it is determined that the remaining amount of the affected layer on the peeled surface side is equal to or less than the threshold value.

13. The processing unit further includes an imaging unit for forming an image by imaging the peeled surface in parallel with or after interrupting the grinding of the substrate; The processing apparatus according to claim 12 , wherein the processor identifies the remaining amount of the affected layer on the peeled surface side of the substrate based on the image.

14. The memory further stores a predetermined amount of finish grinding; The processing apparatus according to claim 12 or 13, wherein the processing unit further includes a finish grinding section for finish-grinding the peeled surface side of the substrate so as to thin the ground substrate by the finish-grinding amount.

15. The memory further stores a predetermined polishing amount; The processing apparatus according to claim 14 , wherein the processing unit further includes a polishing section for polishing the peeled surface side of the substrate after finish grinding so as to thin the substrate by the polishing amount.

16. A processing apparatus for manufacturing a plurality of substrates from a workpiece including a first surface and a second surface located opposite to the first surface, the initial thickness of which is a distance between a first reference point included in the first surface and a second reference point located opposite to the first reference point, the processing apparatus comprising: a laser beam irradiation unit for forming an altered layer inside the workpiece by irradiating the workpiece from the first surface side with a laser beam having a wavelength that transmits through the material of the workpiece, and relatively moving the workpiece and the focal point where the laser beam is focused so that the focal point passes through a point located at a target depth from the first reference point; a separation unit for separating the workpiece using the deteriorated layer as a separation starting point to produce a substrate including the first surface and a peeled surface located opposite the first surface, with a portion of the deteriorated layer remaining on the peeled surface side, and a thinned workpiece including the second surface and a peeled surface located opposite the second surface, with a remainder of the deteriorated layer remaining on the peeled surface side; a processing unit for processing the thinned workpiece so as to remove the altered layer remaining on the peeled surface side; a controller for controlling the laser beam irradiation unit, the separation unit, and the processing unit; The controller a memory for storing the initial thickness, a threshold value for the remaining amount of the altered layer, a target thickness that is preset as the distance between the first reference point and a third reference point on the peeled surface located opposite the first reference point at the time when it is determined that the remaining amount of the altered layer on the peeled surface side has become equal to or less than the threshold value, and a margin amount that is referenced together with the target thickness when setting the target depth; a processor that, when it is determined that the remaining amount of the affected layer on the peeled surface side has become equal to or less than the threshold value, stores in the memory the thinned workpiece side feedback amount calculated by subtracting the target depth and the thickness obtained by measuring the distance between the second reference point and a fourth reference point on the peeled surface located on the opposite side of the second reference point from the initial thickness, in place of the margin amount; and a processing device comprising:

17. The processing apparatus according to claim 16, wherein the processing unit includes a grinding section for grinding the peeled surface side of the thinned workpiece until it is determined that the remaining amount of the affected layer on the peeled surface side is equal to or less than the threshold value.

18. The processing unit further includes an imaging unit for forming an image by imaging the peeled surface in parallel with or after interrupting the grinding of the thinned workpiece, The processing apparatus according to claim 17 , wherein the processor identifies the remaining amount of the affected layer on the surface to be peeled of the thinned workpiece based on the image.

19. The memory further stores a predetermined amount of finish grinding; The processing device according to claim 17 or 18, wherein the processing unit further includes a finish grinding section for finish grinding the peeled surface side of the thinned workpiece so as to thin the ground thinned workpiece by the finish grinding amount.

20. The memory further stores a predetermined polishing amount; The processing apparatus according to claim 19 , wherein the processing unit further includes a polishing section for polishing the peeled surface side of the thinned workpiece so as to thin the finish-ground thinned workpiece by the polishing amount.

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