Wafer production method and wafer production device

Abstract

To provide a wafer generation method capable of reducing a processing defect by removing peeling chips which are generated in a case where a wafer is peeled from an ingot, and a wafer generation device.SOLUTION: A wafer generation method includes: a peeling layer forming step 1 of forming a peeling layer including a modified part and a crack by relatively moving an ingot and a light condensing point in a state where the light condensing point of a laser beam of a wavelength having transmissivity with respect to the ingot is positioned in a depth corresponding to a thickness of a wafer which should be generated; a wafer generating step 2 of peeling the wafer from the ingot with the peeling layer defined as a starting point; a tape sticking step 3 of sticking an adhesive tape to at least any one of a peeling surface of the wafer and a peeling surface of the ingot; a tape peeling step 4 of peeling the adhesive tape, thereby removing peeling chips, which are deposited on the peeling surface, from the peeling surface; and a grinding step 5 of grinding the peeling surface from which the peeling chips are removed.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a wafer production method and a wafer production apparatus. [Background technology]

[0002] As a method for producing wafers such as semiconductor wafers on which devices are formed, a method is generally known in which a cylindrical ingot is thinly sliced ​​with a wire saw and the front and back surfaces are polished. However, cutting with a wire saw has the problem of being uneconomical because most of the ingot is discarded.

[0003] To solve this problem, a technique has been proposed in which a laser beam having a wavelength that is transparent to the ingot is irradiated with the focal point positioned inside the ingot to form a delamination layer, and the wafer is delaminated from the delamination layer (see Patent Documents 1 and 2). The delamination surface of the wafer delaminated from the ingot in this way is ground to form a wafer with a predetermined thickness. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-111143 [Patent Document 2] Japanese Patent Application Publication No. 2019-102513 Summary of the Invention [Problem to be solved by the invention]

[0005] However, after the separation, thorn-like debris remains on the wafer and ingot as contaminants. If the wafer is ground in this state, the thorn-like debris may become lodged in the grinding wheel, resulting in a deterioration in processing quality and chipping of the grinding wheel.

[0006] The present invention has been made in consideration of the above problems, and its object is to provide a wafer production method and wafer production apparatus that can remove peeled debris generated when a wafer is peeled from an ingot and reduce processing defects. [Means for solving the problem]

[0007] In order to solve the above-mentioned problems and achieve the object, the wafer production method of the present invention is a wafer production method for producing a wafer from an ingot having a first surface and a second surface opposite to the first surface, and includes a peeling layer formation step of forming a peeling layer including a modified portion and a crack by relatively moving the ingot and the focal point of a laser beam having a wavelength that is transparent to the ingot, while positioning the focal point at a depth corresponding to the thickness of the wafer from the first surface side; a wafer production step of peeling a wafer from the ingot using the peeling layer as a starting point; and, after performing the wafer production step, attaching an adhesive tape to at least one of the peeling surface of the wafer and the peeling surface of the ingot. The peeled debris present on the peeling surface is then attached to the adhesive tape. a tape peeling step of removing peeling debris adhering to the release surface from the release surface by peeling off the adhesive tape applied in the tape peeling step; and a grinding step of grinding the release surface from which the peeling debris has been removed after the tape peeling step has been performed. Furthermore, the direction in which the adhesive tape is applied in the tape application step is preferably a direction perpendicular to the processing feed direction in which the modified portion was formed in the release layer formation step.

[0008] The wafer production apparatus of the present invention is a wafer production apparatus for producing wafers from an ingot, and includes: a laser beam irradiation unit that irradiates a laser beam having a wavelength that is transparent to the ingot with the focal point of the laser beam positioned at a depth from the top surface of the ingot corresponding to the thickness of the wafer to be produced, and forms a peeled layer; a delamination unit that delaminates the wafer from the ingot using the peeled layer formed by the laser beam irradiation unit as a starting point; and a peeled debris removal unit that attaches an adhesive tape to at least one of the delamination surface of the wafer and the delamination surface of the ingot delaminated by the delamination unit, and removes the peeled debris from the delamination surface by peeling off the adhesive tape in a state in which the peeled debris exists on the delamination surface and adheres the adhesive tape to the tape; The peeling debris was removed and a grinding unit including grinding means for grinding and flattening the peeled surface. Furthermore, the direction in which the peeling debris removing unit applies the adhesive tape is preferably a direction perpendicular to the processing feed direction in which the laser beam irradiating unit forms the peeling layer. [Effects of the Invention]

[0009] The present invention can remove the peeled debris generated when the wafer is peeled from the ingot, thereby reducing processing defects. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a perspective view of an ingot to be processed in a wafer production method according to an embodiment. [Figure 2] FIG. 2 is a side view of the ingot shown in FIG. [Figure 3] FIG. 3 is a flowchart showing the flow of the wafer production method according to the embodiment. [Figure 4] FIG. 4 is a perspective view illustrating the release layer forming step shown in FIG. [Figure 5] FIG. 5 is a top view of the ingot in FIG. [Figure 6] FIG. 6 is a side view showing one state of the wafer producing step shown in FIG. [Figure 7]FIG. 7 is a side view showing a state after FIG. 6 of the wafer production step shown in FIG. [Figure 8] FIG. 8 is a side view showing an example of the configuration of a peeled debris removing unit that performs the tape applying step and the tape peeling step shown in FIG. [Figure 9] FIG. 9 is a top view showing one state of the tape application step shown in FIG. [Figure 10] FIG. 10 is a side view showing one state of the tape peeling step shown in FIG. [Figure 11] FIG. 11 is a diagram illustrating an example of the grinding step shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0011] Modes (embodiments) for carrying out the present invention will be described in detail with reference to the drawings. The present invention is not limited to the contents described in the following embodiments. Furthermore, the components described below include those that can be easily imagined by a person skilled in the art and those that are substantially the same. Furthermore, the configurations described below can be combined as appropriate. Furthermore, various omissions, substitutions, or modifications of the configuration can be made within the scope of the gist of the present invention.

[0012] [Embodiment] A method for producing a wafer 30 and a wafer production apparatus 100 according to an embodiment of the present invention will be described with reference to the drawings. The method for producing a wafer 30 according to the embodiment is a method for producing the wafer 30 shown in Fig. 7 from the ingot 10 shown in Fig. 1 and Fig. 2 using the wafer production apparatus 100 shown in Fig. 4, Fig. 6, Fig. 7, Fig. 8, Fig. 10, and Fig. 11.

[0013] (SiC single crystal ingot) First, the configuration of an ingot 10 to be processed in the method for producing a wafer 30 according to the embodiment of the present invention will be described. Fig. 1 is a perspective view of the ingot 10 to be processed in the method for producing a wafer 30 according to the embodiment. Fig. 2 is a side view of the ingot 10 shown in Fig. 1.

[0014] 1 and 2, the ingot 10 is a single-crystal SiC ingot made of silicon carbide (SiC) and formed into a cylindrical shape as a whole. In this embodiment, the ingot 10 is a hexagonal single-crystal SiC ingot. The ingot 10 has a first surface 11, a second surface 12, a peripheral surface 13, a first orientation flat 14, and a second orientation flat 15.

[0015] The first surface 11 is circular and is one end surface of the cylindrical ingot 10. The second surface 12 is circular and is the end surface of the cylindrical ingot 10 opposite the first surface 11. The second surface 12 corresponds to the bottom surface of the ingot 10. The peripheral surface 13 is a surface that connects the outer edge of the first surface 11 and the outer edge of the second surface 12.

[0016] The first orientation flat 14 is a flat formed on a part of the peripheral surface 13 to indicate the crystal orientation of the ingot 10. The second orientation flat 15 is a flat formed on a part of the peripheral surface 13 to indicate the crystal orientation of the ingot 10. The second orientation flat 15 is perpendicular to the first orientation flat 14. The length of the first orientation flat 14 is longer than the length of the second orientation flat 15.

[0017] The ingot 10 also has a c-axis 18 that is inclined at an off angle 20 in a tilt direction 17 toward the second orientation flat 15 relative to a normal 16 to the first surface 11, and a c-plane 19 that is perpendicular to the c-axis 18. The tilt direction 17 of the c-axis 18 from the normal 16 is perpendicular to the extension direction of the second orientation flat 15 and is parallel to the first orientation flat 14. The c-plane 19 is inclined at the off angle 20 relative to the first surface 11 of the ingot 10.

[0018] Countless c-planes 19 are set in the ingot 10 at the molecular level of the ingot 10. In the embodiment, the ingot 10 has an off-angle 20 set to 1°, 4°, or 6°, but in the present invention, the ingot 10 may be manufactured with the off-angle set freely within the range of 1° to 6°, for example. After the first surface 11 of the ingot 10 is ground by a grinding device, the ingot 10 is polished by a polishing device to form the first surface 11 into a mirror finish.

[0019] (Wafer 30 Production Method and Wafer Production Apparatus 100) Next, a method for producing a wafer 30 according to an embodiment of the present invention will be described. Fig. 3 is a flowchart showing the flow of the method for producing a wafer 30 according to the embodiment. The method for producing a wafer 30 includes a release layer forming step 1, a wafer producing step 2, a tape applying step 3, a tape peeling step 4, and a grinding step 5.

[0020] The peeling layer forming step 1, wafer generating step 2, tape applying step 3, tape peeling step 4, and grinding step 5 of the embodiment are performed using a wafer generating apparatus 100 shown in Figures 4, 6, 7, 8, 10, and 11. The wafer generating apparatus 100 includes a laser beam irradiation unit 110 that performs the peeling layer forming step 1, a peeling unit 130 that performs the wafer generating step 2, a peeling debris removal unit 140 that performs the tape applying step 3 and the tape peeling step 4, a grinding unit 170 that performs the grinding step 5, and holding tables 120, 160, and 180.

[0021] <Release layer formation step 1> Fig. 4 is a perspective view showing the peeling layer forming step 1 shown in Fig. 3. Fig. 5 is a top view of the ingot 10 in Fig. 4. The peeling layer forming step 1 is a step in which a laser beam 112 is used to form a peeling layer 23 including modified portions 21 and cracks 22 from the first surface 11 side of the ingot 10 to a depth corresponding to the thickness of the wafer 30 to be produced.

[0022] The peeling layer forming step 1 of the embodiment is performed by the laser beam irradiation unit 110 of the wafer generating apparatus 100. The laser beam irradiation unit 110 has, for example, an oscillator that emits a laser beam 112, a condenser 111 that condenses the laser beam 112 toward the ingot 10 held on the holding table 120, and various optical components that guide the laser beam 112 from the oscillator to the condenser 111.

[0023] The holding table 120 holds the ingot 10 on a holding surface 121. The holding surface 121 has a disk shape and is made of porous ceramic or the like. In this embodiment, the holding surface 121 is a flat surface parallel to the horizontal direction. The holding surface 121 is connected to a vacuum suction source, for example, via a vacuum suction path. The holding table 120 suction-holds the second surface 12 of the ingot 10 placed on the holding surface 121.

[0024] The laser beam irradiation unit 110 irradiates the ingot 10 held on the holding surface 121 of the holding table 120 with a laser beam 112 having a wavelength that allows transmission. The laser beam irradiation unit 110 is movable relative to the holding table 120 by a moving unit (not shown). In the following description, the X-axis direction is one direction in a horizontal plane. The Y-axis direction is a direction perpendicular to the X-axis direction in a horizontal plane. In the embodiment, the X-axis direction is the processing feed direction, and the Y-axis direction is the indexing feed direction.

[0025] In the peeling layer forming step 1, first, the second surface 12 side of the ingot 10 is suction-held on the holding surface 121 of the holding table 120. At this time, the second orientation flat 15 of the ingot 10 is adjusted to be parallel to the processing feed direction (X-axis direction). Next, the focal point 113 of the laser beam 112 is positioned at a depth inside the ingot 10 corresponding to the thickness of the wafer 30 to be produced (see FIG. 6, etc.). The laser beam 112 is a pulsed laser beam with a wavelength that is transparent to the ingot 10.

[0026] In the peeling layer forming step 1, next, the condenser 111 and the holding table 120 of the laser beam irradiation unit 110 are moved relatively with the focal point 113 positioned at a depth corresponding to the thickness of the wafer 30 to be produced inside the ingot 10 (see FIG. 6, etc.). That is, the laser beam 112 is irradiated toward the ingot 10 while the focal point 113 and the ingot 10 are moved relatively in directions parallel to the first surface 11 (X and Y directions).

[0027] In the peeling layer formation step 1, SiC is separated into Si (silicon) and C (carbon) by irradiation with a pulsed laser beam 112. The next pulsed laser beam 112 is absorbed by the previously formed C, and modified regions 21, in which SiC is separated into Si and C in a chain reaction, are formed inside the ingot 10 along the processing feed direction, and cracks 22 extending from the modified regions 21 along the c-plane 19 (see FIG. 2 ) are generated. That is, in the embodiment, the cracks 22 extend in the indexing feed direction (Y-axis direction). In this way, in the peeling layer formation step 1, a peeling layer 23 is formed, which includes the modified regions 21 and the cracks 22 formed from the modified regions 21 along the c-plane 19.

[0028] <Wafer production step 2> Fig. 6 is a side view showing one state of wafer production step 2 shown in Fig. 5. Fig. 7 is a side view showing one state of wafer production step 2 shown in Fig. 5 after Fig. 6. Wafer production step 2 is a step of peeling a wafer 30 from ingot 10 starting from peeling layer 23 formed in peeling layer formation step 1.

[0029] The wafer production step 2 of the embodiment is performed by the delamination unit 130 of the wafer production apparatus 100. The delamination unit 130 includes, for example, an ingot holding unit 131 that holds the ingot 10, a wafer holding unit 132 that holds the wafer 30 to be produced, and a moving unit (not shown) that moves the ingot holding unit 131 and the wafer holding unit 132 relative to each other.

[0030] The ingot holding unit 131 holds the ingot 10 on a holding surface 133. The holding surface 133 has a disk shape and is made of porous ceramic or the like. In this embodiment, the holding surface 133 is a flat surface parallel to the horizontal direction. The holding surface 133 is connected to a vacuum suction source, for example, via a vacuum suction path. The ingot holding unit 131 suction-holds the second surface 12 of the ingot 10 placed on the holding surface 133.

[0031] The wafer holding unit 132 suction-holds the wafer 30 to be produced on a holding surface 134. The holding surface 134 has a disk shape and is made of porous ceramic or the like. In this embodiment, the holding surface 134 is a flat surface that is parallel to the horizontal direction and faces the holding surface 133 of the ingot holding unit 131. The holding surface 134 is connected to a vacuum suction source, for example, via a vacuum suction path. The wafer holding unit 132 suction-holds the first surface 11 of the ingot 10 that is in contact with the holding surface 134. The wafer holding unit 132 can be moved toward and away from the ingot holding unit 131 by a moving unit (not shown).

[0032] The ingot holding unit 131 may be shared with the holding table 120. That is, the ingot 10 on which the peeling layer 23 has been formed by the laser beam irradiation unit 110 may be transported on the holding table 120 to a position facing the wafer holding unit 132.

[0033] As shown in Figure 6, in wafer production step 2, first, the second surface 12 of the ingot 10 is suction-held by the holding surface 133 of the ingot holding unit 131. Next, the wafer holding unit 132 is brought close to the ingot holding unit 131, and the first surface 11 of the ingot 10 is suction-held by the holding surface 134. In this state, as shown in Figure 7, the wafer holding unit 132 is then moved away from the ingot holding unit 131. As a result, the ingot 10 is pulled up and down, and is separated starting from the separation layer 23, and the separated portion of the ingot 10 on the first surface 11 side is produced as the wafer 30.

[0034] <Tape application step 3 and tape removal step 4> Fig. 8 is a side view showing an example of the configuration of a peeled debris removal unit 140 that performs tape application step 3 and tape peeling step 4 shown in Fig. 5. Fig. 9 is a top view showing one state of tape application step 3 shown in Fig. 5. Fig. 10 is a side view showing one state of tape peeling step 4 shown in Fig. 5.

[0035] The tape application step 3 is performed after the wafer production step 2. The tape application step 3 is a step of applying an adhesive tape 141 to at least one of the peeled surface 31 of the wafer 30 and the peeled surface 24 of the ingot 10. The tape peeling step 4 is a step of removing peeled debris adhering to the peeled surfaces 31, 24 from the peeled surfaces 31, 24 by peeling off the adhesive tape 141 applied in the tape application step 3.

[0036] The tape application step 3 and the tape peeling step 4 described later in the embodiment are performed by the peeled debris removal unit 140 of the wafer production apparatus 100. The peeled debris removal unit 140 is a unit that applies an adhesive tape 141 to the peeled surface 31, 24 of the wafer 30 or ingot 10 held on the holding table 160, and removes the peeled debris from the peeled surface 31, 24 by peeling off the applied adhesive tape 141. The peeled debris removal unit 140 has a support roller 150, conveying rollers 151, 152, a peeling roller 153, a release paper winding roller 154, an adhesion roller 155, and a tape winding roller 156.

[0037] The adhesive tape 141 is flexible overall and includes a base layer 142 made of a non-adhesive synthetic resin, and a glue layer 143 made of an adhesive synthetic resin that adheres to the release surfaces 31 and 24 and laminated on the base layer 142. In the embodiment, the adhesive tape 141 is formed as a long, strip-shaped member, and is wound into a roll with release paper 144 attached to the glue layer 143 to form a tape roll 145.

[0038] The support roller 150 is formed in a cylindrical shape with a horizontal axis and is provided so as to be rotatable about its axis. In the embodiment, the axis of the support roller 150 is parallel to the X-axis direction. The support roller 150 is inserted into the core of the tape roll 145 and supports the tape roll 145 about its horizontal axis. The support roller 150 has an outer circumferential surface fixed to the inner circumferential surface of the core of the tape roll 145, and rotates about its axis to feed the adhesive tape 141 onto the holding surface 161 of the holding table 160 in order from the end.

[0039] The transport rollers 151 and 152 are formed in a cylindrical shape with their axes parallel to the axis of the support roller 150, and are provided to be rotatable about their axes. The transport roller 151 is disposed above one end of the holding table 160 in the X-axis direction and between the holding table 160 and the support roller 150. The transport roller 152 is disposed above the other end of the holding table 160 in the X-axis direction. The transport rollers 151 and 152 transport the adhesive tape 141 from the support roller 150 to the tape winding roller 156, and apply tension to the adhesive tape 141 to prevent slack from occurring in the adhesive tape 141. The transport rollers 151 and 152 press the base layer 142 of the adhesive tape 141 toward the holding table 160 with their outer circumferential surfaces to apply tension to the adhesive tape 141.

[0040] Peeling roller 153 is formed in a cylindrical shape with its axis parallel to the axes of support roller 150 and transport rollers 151 and 152, and is provided so as to be rotatable about its axis. Peeling roller 153 is disposed between support roller 150 and transport roller 151, and peels release paper 144 affixed to glue layer 143 of adhesive tape 141 from adhesive tape 141. The transport roller 151 presses release paper 144 affixed to adhesive tape 141 fed from support roller 150 with its outer circumferential surface, thereby peeling release paper 144 from adhesive tape 141.

[0041] The release paper winding roller 154 is formed in a cylindrical shape with its axis parallel to the axes of the support roller 150, the conveying rollers 151 and 152, and the peeling roller 153, and is rotated about its axis by a driving device such as a motor (not shown). The release paper winding roller 154 is disposed below the support roller 150. As the release paper winding roller 154 rotates, it winds up onto its outer circumferential surface the release paper 144 that has been peeled off by the peeling roller 153 from the adhesive tape 141 fed from the support roller 150. The release paper 144 wound around the release paper winding roller 154 is wound in a roll shape to form a release paper roll 146.

[0042] The bonding roller 155 is formed in a cylindrical shape with its axis parallel to the axes of the support roller 150, the conveying rollers 151 and 152, the peeling roller 153, and the release paper winding roller 154, and is supported so as to be rotatable about its axis. The bonding roller 155 is disposed above the holding surface 161 of the holding table 160. The bonding roller 155 is provided with a movement mechanism (not shown) so as to be able to move up and down in a direction perpendicular to the holding surface 161 of the holding table 160, and to be able to move along the holding surface 161 in a direction perpendicular to its axis.

[0043] The application roller 155 rolls along the holding surface 161 while being lowered by the moving mechanism, thereby pressing the adhesive tape 141 supplied from the support roller 150 onto the holding surface 161 of the holding table 160 against the peeled surfaces 31, 24 of the wafer 30 or ingot 10 held by suction on the holding surface 161 of the holding table 160, thereby applying the adhesive tape 141. As a result, peeled debris present on the peeled surfaces 31, 24 adheres to the adhesive tape 141.

[0044] The tape winding roller 156 is formed in a cylindrical shape with its axis parallel to the axes of the support roller 150, the conveying rollers 151 and 152, the peeling roller 153, the release paper winding roller 154, and the adhering roller 155, and is rotated about its axis by a driving device such as a motor (not shown). The tape winding roller 156 is disposed above the other end of the holding table 160 in the X-axis direction and the conveying roller 152. As the tape winding roller 156 rotates, it pulls out the adhesive tape 141 from the tape roll 145 supported by the support roller 150 and winds the adhesive tape 141 onto its outer circumferential surface. The adhesive tape 141 wound around the tape winding roller 156 is wound into a roll to form a waste tape roll 147.

[0045] The tape winding roller 156 rotates with the adhesive tape 141 attached to the peeling surfaces 31, 24 of the wafer 30 or ingot 10 held by suction on the holding surface 161 of the holding table 160, thereby peeling the adhesive tape 141 from the peeling surfaces 31, 24. This removes peeling debris that is present on the peeling surfaces 31, 24 and has adhered to the adhesive tape 141 from the peeling surfaces 31, 24.

[0046] The holding table 160 holds the ingot 10 or the wafer 30 on a holding surface 161. The holding surface 161 has a disk shape made of porous ceramic or the like. In this embodiment, the holding surface 161 is a plane parallel to the horizontal direction. The holding surface 161 is connected to a vacuum suction source, for example, via a vacuum suction path. The holding table 160 suction-holds the second surface 12 of the ingot 10 placed on the holding surface 161, or the first surface 11 of the wafer 30 peeled from the ingot 10 in the wafer production step 2.

[0047] The holding table 160 may be shared with the ingot holding unit 131. That is, the ingot 10 from which the wafer 30 has been peeled by the peeling unit 130 may be transported on the ingot holding unit 131 to a position where the peeled surface 24 faces the adhesive layer 143 of the adhesive tape 141. The holding table 160 may be shared with the wafer holding unit 132. That is, the wafer 30 from which the ingot 10 has been peeled by the peeling unit 130 may be transported on the wafer holding unit 132 to a position where the peeled surface 31 faces the adhesive layer 143 of the adhesive tape 141.

[0048] The following describes the removal of peeled debris from peeled surface 24 of ingot 10 in tape application step 3 and tape peeling step 4. As shown in Fig. 8, in tape application step 3, first, second surface 12 of ingot 10 is suction-held by holding surface 161 of holding table 160 and positioned below adhesive tape 141 fed from support roller 150. At this time, ingot 10 is held on holding surface 161 so that second orientation flat 15 is parallel to the processing feed direction (X-axis direction).

[0049] Next, as shown in FIGS. 8 and 9 , the application roller 155 is lowered and rolled along the holding surface 161 in a direction perpendicular to the axis, i.e., the Y-axis direction, to apply the adhesive tape 141 to the release surface 24 of the ingot 10. As a result, peeling debris present on the release surface 24 adheres to the adhesive tape 141. Note that the application of the adhesive tape 141 by the application roller 155 may be performed multiple times on one release surface 24, 41. In this case, the application roller 155 may roll back and forth to apply the tape, or may return to its original position and roll again to apply the tape. After the adhesive tape 141 has been applied to the entire release surface 24, the application roller 155 is raised, separated from the adhesive tape 141, and returned to its predetermined initial position. The adhesive tape 141 remains attached to the release surface 24 due to the adhesive force of the glue layer 143.

[0050] 10, in tape peeling step 4, the tape winding roller 156 is rotated to wind up the adhesive tape 141. As a result, the adhesive tape 141 attached to the peeling surface 24 of the ingot 10 is pulled upward and peeled off from the end portion on the tape winding roller 156 side, and peeling debris adhering to the adhesive tape 141 is removed from the peeling surface 24. The peeling debris is wound around the tape winding roller 156 together with the adhesive tape 141 and collected.

[0051] As in the embodiment, the direction in which the adhesive tape 141 is applied in the tape application step 3, i.e., the direction in which the application roller 155 is rolled, is preferably the Y-axis direction orthogonal to the processing feed direction (X-axis direction) in which the modified section 21 was formed in the release layer formation step 1. This allows peeling debris from the release surface 24 to be more effectively removed in the tape peeling step 4.

[0052] Although the above description has been made on the case where the peeled debris is removed from the peeled surface 24 of the ingot 10, the same procedure can also be used to remove the peeled debris from the peeled surface 31 of the wafer 30.

[0053] <Grinding step 5> Fig. 11 is a diagram showing an example of grinding step 5 shown in Fig. 5. Grinding step 5 is performed after tape peeling step 4. Grinding step 5 is a step of grinding the peeled surface 24 of ingot 10 from which peeled debris has been removed.

[0054] Grinding step 5 of the embodiment is performed by the grinding unit 170 of the wafer production apparatus 100. The grinding unit 170 includes grinding means for grinding and flattening the delaminated surface 24 of the ingot 10 or the delaminated surface 31 of the wafer 30 held on the holding table 180. The grinding means includes a spindle 171 which is a rotating shaft member, a grinding wheel 172 attached to the lower end of the spindle 171, a grinding stone 173 attached to the lower surface of the grinding wheel 172, and a grinding water supply nozzle (not shown) for supplying grinding water.

[0055] The holding table 180 holds the ingot 10 on a holding surface 181. The holding surface 181 has a disk shape and is made of porous ceramic or the like. In this embodiment, the holding surface 181 is a flat surface parallel to the horizontal direction. The holding surface 181 is connected to a vacuum suction source, for example, via a vacuum suction path. The holding table 180 suction-holds the second surface 12 of the ingot 10 or the first surface 11 of the wafer 30 placed on the holding surface 181.

[0056] The holding table 180 may be shared with the holding table 160. That is, the ingot 10 or the wafer 30 from which the peeled debris has been removed from the peeled surfaces 24, 31 by the peeled debris removal unit 140 may be transported on the holding table 160 to a position facing the grinding unit 170.

[0057] Grinding of the peeled surface 24 of the ingot 10 in the grinding step 5 will be described. As shown in FIG. 11 , in the grinding step 5, first, the second surface 12 side of the ingot 10 is suction-held on the holding surface 181 of the holding table 180. Next, while the holding table 180 is rotated about its axis, the grinding wheel 172 is rotated about its axis. The grinding wheel 172 rotates about an axis parallel to the axis of the holding table 180.

[0058] Next, grinding water is supplied from the grinding water supply nozzle, and the grinding stone 173 attached to the underside of the grinding wheel 172 is moved toward the holding table 180 at a predetermined feed rate, thereby grinding the ingot 10 from the side of the peeled surface 24 with the grinding stone 173. As a result, irregularities on the peeled surface 24 of the ingot 10 are removed.

[0059] Although the above description has been given of the case where the peeled surface 24 of the ingot 10 is ground, the same procedure can also be used to grind the peeled surface 31 of the wafer 30.

[0060] When grinding step 5 is completed, all the steps in the flowchart shown in Fig. 3 are completed. Thereafter, the steps in the flowchart shown in Fig. 3 are repeatedly performed until a predetermined number of wafers 30 are produced from the ingot 10. Note that, in the steps in the flowchart shown in Fig. 3, the surface that is treated as the next first surface 11 is the surface obtained after the separation surface 24 has been ground in grinding step 5.

[0061] As described above, in the wafer 30 production method and wafer production apparatus 100 of the embodiment, the peeled debris is removed by attaching and peeling off the adhesive tape 141 to the peeled surface 24, and then the peeled surface 24 is ground. This makes it possible to remove even the peeled debris firmly attached to the peeled surface 24, thereby making it possible to suppress problems caused by the peeled debris getting stuck in the grinding wheel 173 in the grinding step 5, thereby contributing to improved processing quality. In addition, since the wafer 30 or ingot 10 is no longer transported with the peeled debris present, there is also the advantage that the inside of the apparatus can be kept clean.

[0062] The present invention is not limited to the above-described embodiment, and can be implemented in various modifications without departing from the gist of the present invention.

[0063] For example, the method for producing wafer 30 may include a step of applying ultrasonic waves or an external force such as wedging into peeling layer 23 after peeling layer formation step 1 and before wafer production step 2. [Explanation of symbols]

[0064] 10 ingots 11 First surface (top surface) 12 The Second Side 21 Reforming section 22 Crack 23 Peeling layer 24 Peeling surface 30 wafers 31 Peeling surface 100 Wafer generation equipment 110 Laser beam irradiation unit 112 Laser Beam 113 Focus point 130 Peeling unit 140 Peeling debris removal unit 170 Grinding Unit

Claims

1. A wafer production method for producing a wafer from an ingot having a first surface and a second surface opposite to the first surface, comprising: a separation layer forming step in which a focal point of a laser beam having a wavelength that is transparent to the ingot is positioned at a depth corresponding to the thickness of the wafer to be produced from the first surface side, and the ingot and the focal point are moved relatively to form a separation layer including a modified portion and a crack; a wafer generating step of peeling a wafer from the ingot starting from the peeling layer; a tape adhering step of adhering an adhesive tape to at least one of the peeled surface of the wafer and the peeled surface of the ingot after the wafer producing step is performed, and adhering peeled debris present on the peeled surface to the adhesive tape; a tape peeling step of removing peeling debris adhering to the release surface from the release surface by peeling off the adhesive tape attached in the tape attaching step; a grinding step of grinding the release surface from which the peeling debris has been removed after the tape peeling step is performed; A method for producing a wafer, comprising:

2. The direction in which the adhesive tape is attached in the tape attachment step is a direction perpendicular to the processing feed direction in which the modified portion was formed in the release layer formation step. A method for producing a wafer according to claim 1.

3. A wafer producing apparatus for producing wafers from an ingot, a laser beam irradiation unit that irradiates a laser beam having a wavelength that is transparent to the ingot with the focal point of the laser beam positioned at a depth from the top surface of the ingot that corresponds to the thickness of the wafer to be produced, thereby forming a peeling layer; a delamination unit that delaminates the wafer from the ingot using the delamination layer formed by the laser beam irradiation unit as a starting point; a peeled debris removal unit that attaches an adhesive tape to at least one of the peeled surface of the wafer and the peeled surface of the ingot that have been peeled by the peeling unit, and removes the peeled debris from the peeled surface by peeling off the adhesive tape in a state where the peeled debris exists on the peeled surface and adheres to the adhesive tape; a grinding unit including a grinding means for grinding and flattening the peeled surface from which the peeled debris has been removed; A wafer generation apparatus comprising:

4. The direction in which the peeling debris removal unit applies the adhesive tape is a direction perpendicular to the processing feed direction in which the laser beam irradiation unit forms the peeling layer.

4. The wafer preparation apparatus according to claim 3.

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