Polishing apparatus, polishing method, and polishing head

Abstract

The invention provides a polishing apparatus, a polishing method, and a polishing head capable of removing debris. The grinding device comprises a first grinding head and a second grinding head. The first polishing head presses the first polishing tool against the peripheral edge portion of the substrate to form a recess in the peripheral edge portion, and the second polishing head presses the second polishing tool against the polishing boundary portion of the recess.

Description

Technical Field

[0001] The invention relates to a grinding device, a grinding method and a grinding head. Background Art

[0002] In recent years, to further increase the density and functionality of semiconductor devices, the development of three-dimensional mounting technology, which involves stacking multiple substrates for three-dimensional integration, has progressed. In this technology, for example, the device surface of a first substrate, on which integrated circuits and electrical wiring are formed, is bonded to the device surface of a second substrate, on which integrated circuits and electrical wiring are also formed.

[0003] After the first and second substrates are bonded, the first substrate is thinned using a lapping or grinding device. This allows integrated circuits to be stacked perpendicular to the device surfaces of the first and second substrates. In this specification, multiple bonded substrates are sometimes referred to as a "stacked substrate" or "composite substrate."

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2021-037585

[0007] Patent Document 2: Japanese Patent Application Laid-Open No. 2022-037426

[0008] Technical problem to be solved by the invention

[0009] Typically, the peripheral edge of the substrate is ground into a rounded shape in advance. When the first substrate having such a rounded peripheral edge is ground, an acute-angled end (blade) is formed on the first substrate.

[0010] Such a blade portion is easily damaged by physical contact. Furthermore, the blade portion can damage the laminated substrate itself during transport. Therefore, to prevent the formation of a blade portion, a grinding tool (e.g., a grinding tape) is pressed against the peripheral edge of the laminated substrate while the laminated substrate is rotated to remove the peripheral edge of the first substrate, forming a depression in the peripheral edge of the laminated substrate.

[0011] However, forming such a recess may sometimes cause a defect called chipping at the polishing boundary of the recess. The chipping may cause a defect in the laminated substrate, and therefore, the chipping needs to be removed.

[0012] This problem is not necessarily limited to laminated substrates (i.e., composite substrates). For example, even in a single substrate that is not a laminated substrate, the formation of a depression may result in the formation of debris at the grinding boundary of the depression. Therefore, even in a single substrate, it is necessary to remove the debris. Summary of the Invention

[0013] Therefore, an object of the present invention is to provide a polishing device, a polishing method, and a polishing head capable of removing debris.

[0014] Methods used to solve technical problems

[0015] In one embodiment, a polishing apparatus is provided. The polishing apparatus comprises: a first polishing head, the first polishing head holding a first polishing tool having a first angle, the first angle being an acute angle; and a second polishing head, the second polishing head holding a second polishing tool having a second angle, the second angle being a right angle or an obtuse angle. The first polishing head presses the first polishing tool against a peripheral edge of a substrate to form a recess in the peripheral edge; and the second polishing head presses the second polishing tool against a polishing boundary of the recess.

[0016] In one embodiment, the first grinding head is equivalent to a rough grinding head that presses a rough grinding tape as the first grinding tool against the peripheral portion to form a depression in the peripheral portion, and the second grinding head is equivalent to a fine grinding head that presses a fine grinding tape as the second grinding tool against the grinding boundary portion. The rough grinding head supports the rough grinding tape in such a manner that the tape angle of the rough grinding tape becomes the first angle, and the fine grinding head supports the fine grinding tape in such a manner that the tape angle of the fine grinding tape becomes the second angle.

[0017] In one embodiment, the rough grinding head and the fine grinding head each include: a pressing component for pressing the rough grinding belt and the fine grinding belt toward the peripheral portion, respectively; a tight front guide roller, which is arranged on the upstream side of the pressing component and adjacent to the pressing component in the conveying direction of the rough grinding belt and the fine grinding belt, respectively; and a tight front guide roller actuator, which moves the tight front guide roller.

[0018] In one embodiment, the immediately preceding guide roller actuator is configured to move the immediately preceding guide roller in an approaching direction toward the pressing member and in a separating direction away from the pressing member.

[0019] In one embodiment, the grinding device includes a motion control unit that controls the motion of the tight-front guide roller actuator, the motion control unit operates the tight-front guide roller actuator to move the tight-front guide roller until the belt angle of the rough-grinding belt becomes the first angle, and the motion control unit operates the tight-front guide roller actuator to move the tight-front guide roller until the belt angle of the fine-grinding belt becomes the second angle.

[0020] In one embodiment, the motion control unit operates the tight front guide roller actuator to make the belt angle become the first angle, thereby moving the rough grinding belt along the depth direction of the substrate to form a recess of a specified depth in the peripheral portion. The motion control unit operates the tight front guide roller actuator to make the belt angle become the second angle, and presses the fine grinding belt against the grinding boundary portion.

[0021] In one embodiment, the operation control unit operates the immediate preceding guide roller actuator to press the fine grinding tape in a region between the immediate preceding guide roller and the pressing member against the grinding boundary portion.

[0022] In one embodiment, the rough grinding head and the fine grinding head each include: a leading guide roller, which is arranged on the upstream side of the immediate leading guide roller in the conveying direction of the rough grinding belt and the fine grinding belt, and is arranged adjacent to the immediate leading guide roller; and a leading guide roller actuator, which moves the leading guide roller, and the leading guide roller actuator moves the leading guide roller until it reaches a third angle larger than the second angle.

[0023] In one embodiment, the grinding device includes a motion control unit that controls the movement of the leading guide roller actuator. The motion control unit operates the leading guide roller actuator to press the fine grinding belt against the grinding boundary portion, and then operates the leading guide roller actuator to move the leading guide roller until the belt angle becomes the third angle.

[0024] In one embodiment, the first grinding head holds a first grinding wheel as the first grinding tool, and the second grinding head holds a second grinding wheel as the second grinding tool. The first grinding wheel has a tapered concave portion forming the first angle, and the second grinding wheel has a tapered convex portion forming the second angle.

[0025] In one embodiment, a polishing method is provided. In the polishing method, a first polishing tool having a first angle is pressed against a peripheral edge of a substrate by a first polishing head to form a recess in the peripheral edge, wherein the first angle is an acute angle, and a second polishing tool having a second angle is pressed against a polishing boundary of the recess by a second polishing head, wherein the second angle is a right angle or an obtuse angle.

[0026] In one embodiment, the first grinding head is equivalent to a rough grinding head that presses a rough grinding tape as the first grinding tool against the peripheral portion to form a depression in the peripheral portion, and the second grinding head is equivalent to a fine grinding head that presses a fine grinding tape as the second grinding tool against the grinding boundary portion, so that the belt angle of the rough grinding tape becomes the first angle, the rough grinding tape is pressed against the peripheral portion to form a depression in the peripheral portion, the belt angle of the fine grinding tape becomes the second angle, and the fine grinding tape is pressed against the grinding boundary portion.

[0027] In one embodiment, in the conveying directions of the rough grinding belt and the fine grinding belt, the front guide roller arranged on the upstream side of the pressing component and adjacent to the pressing component is operated to make the belt angle become the first angle, and the front guide roller is operated to make the belt angle become the second angle.

[0028] In one embodiment, in the conveying directions of the rough grinding tape and the fine grinding tape, a preceding guide roller arranged upstream of and adjacent to the preceding guide roller is operated to set the belt angle to a third angle larger than the second angle.

[0029] In one embodiment, the first grinding head holds a first grinding wheel as the first grinding tool, and the second grinding head holds a second grinding wheel as the second grinding tool. The first grinding wheel having a tapered concave portion forming the first angle is pressed against the peripheral portion to form a recess in the peripheral portion, and the second grinding wheel having a tapered convex portion forming the second angle is pressed against the grinding boundary portion.

[0030] In one embodiment, a polishing head is provided. The polishing head includes: a pressing member for pressing the polishing tape toward the peripheral portion; a front guide roller disposed upstream of and adjacent to the pressing member in the conveying direction of the polishing tape; and a front guide roller actuator for moving the front guide roller. The front guide roller actuator moves the front guide roller until the polishing tape reaches a first angle, which is an acute angle, and the front guide roller actuator moves the front guide roller until the polishing tape reaches a second angle, which is a right angle or an obtuse angle.

[0031] In one embodiment, the immediately preceding guide roller actuator is configured to move the immediately preceding guide roller in an approaching direction toward the pressing member and in a separating direction away from the pressing member.

[0032] In one embodiment, the grinding head moves the grinding tape in the depth direction of the substrate while the belt angle is changed to the first angle by the tight front guide roller actuator, thereby forming a recess having a specified depth in the peripheral portion. The grinding head changes the belt angle to the second angle by the tight front guide roller actuator, thereby pressing the grinding tape against the grinding boundary portion of the recess.

[0033] In one embodiment, the grinding head includes: a leading guide roller, which is arranged on the upstream side of the tight leading guide roller in the conveying direction of the grinding belt and is arranged adjacent to the tight leading guide roller; and a leading guide roller actuator, which moves the leading guide roller, and the leading guide roller actuator moves the leading guide roller until the belt angle becomes a third angle larger than the second angle.

[0034] Effects of the Invention

[0035] According to the above method, the grinding device can remove the debris. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a side view showing the peripheral portion of the composite substrate to be polished.

[0037] Figure 2 This is a diagram showing one embodiment of a polishing device.

[0038] Figure 3 middle, Figure 3 (a) and Figure 3 (b) is a diagram showing an immediate front guide roller actuator for moving the immediate front guide roller.

[0039] Figure 4 middle, Figure 4 (a) and Figure 4 (b) is a diagram showing a leading guide roller actuator for moving the leading guide roller.

[0040] Figure 5 middle, Figure 5 (a) to Figure 5 (d) is a diagram showing the polishing step of the first wafer.

[0041] Figure 6 FIG. 1 is a diagram showing a polishing flow of a first wafer using a polishing apparatus.

[0042] Figure 7 This is a diagram showing a concave polishing boundary.

[0043] Figure 8 This figure shows a polishing head that removes debris using a polishing tape.

[0044] Figure 9This is a diagram showing another embodiment of the polishing device.

[0045] Figure 10A This is a diagram showing another embodiment of the polishing device.

[0046] Figure 10B This is a diagram showing another embodiment of the polishing device.

[0047] Figure 10C It is a diagram showing a pressing member having a first angle.

[0048] Figure 10D It is a diagram showing a pressing member having a second angle.

[0049] Figure 11 This is a diagram showing another embodiment of the polishing device.

[0050] Figure 12 middle, Figure 12 (a) is a diagram showing a grinding wheel having a tapered recess, Figure 12 (b) is a diagram showing a grinding wheel having a tapered convex portion.

[0051] Figure 13 middle, Figure 13 (a) to Figure 13 (c) is a diagram showing the polishing step of the peripheral portion of the wafer.

[0052] Figure 14 middle, Figure 14 (a) and Figure 14 (b) is a diagram showing the manufacturing process of the composite wafer.

[0053] Explanation of symbols

[0054] 3. Substrate holding device

[0055] 10 Motion control unit

[0056] 10a Storage device

[0057] 10b processing device

[0058] 12 holding platform

[0059] 12a substrate holding surface

[0060] 12b opening

[0061] 15 rotating devices

[0062] 16 vacuum lines

[0063] 17 axes

[0064] 18 liquid supply nozzles

[0065] 21 Pressing parts

[0066] 21A pressing surface

[0067] 21B inclined surface

[0068] 22A first grinding head

[0069] 22B second grinding head

[0070] 23 mobile actuator

[0071] 26 Pull out the scroll

[0072] 27 take-up reels

[0073] 30 belt conveyor mechanism

[0074] 32 sensor targets

[0075] 33 displacement sensor

[0076] 36 tight front guide roller

[0077] 37 advance guide roller

[0078] 200 device layers

[0079] 210A, 210B pressing parts

[0080] 210A-1 pressing surface

[0081] 210A-2 inclined surface

[0082] 210B-1 pressing surface

[0083] 210B-2 inclined surface

[0084] 300 Tight Front Guide Roller Actuator

[0085] 301 leading guide roller actuator

[0086] W composite substrate

[0087] W1 first substrate

[0088] W2 second substrate

[0089] CH debris

[0090] PB grinding boundary

[0091] CL axis

[0092] T1 coarse grinding belt

[0093] T2 fine grinding belt

[0094] θ1 first angle

[0095] θ2 second angle

[0096] θ3 third angle

[0097] θα first angle

[0098] θβ second angle

[0099] θa first angle

[0100] θb second angle

[0101] AR1 is the area facing the pressing surface

[0102] AR2 is the area facing the inclined surface

[0103] G1 grinding wheel

[0104] G1a main body

[0105] G1b tapered recess

[0106] G2 grinding wheel

[0107] G2a main body

[0108] G2b conical convex part

[0109] RA drive actuator

[0110] RA-1 rotary axis. DETAILED DESCRIPTION

[0111] Modes for carrying out the invention

[0112] The following describes embodiments of the present invention with reference to the accompanying drawings. In the accompanying drawings described below, identical or equivalent components are denoted by the same reference numerals, and duplicate descriptions are omitted. Among the multiple embodiments described below, if the structure of one embodiment is identical to that of the other embodiments, the duplicate descriptions thereof are omitted.

[0113] Figure 1 : is a side view showing the peripheral edge of the composite substrate to be polished. Figure 1 As shown, the composite substrate W has a structure in which a first substrate W1 and a second substrate W2 are overlapped. The first substrate W1 is a device substrate (or device wafer) having a device layer 200 on which a circuit pattern and the like are formed.

[0114] The second substrate W2 is a support substrate (or support wafer) for supporting the first substrate W1. The device layer 200 faces the second substrate W2. The first substrate W1 and the second substrate W2 are bonded using an adhesive or without using an adhesive.

[0115] A circular wafer is an example of a substrate, and the substrate to be polished in the present invention is not limited to a circular wafer. In the embodiments described below, a wafer is used as an example of a substrate. Therefore, in the following description, the composite substrate W is referred to as a composite wafer W, the first substrate W1 is referred to as a first wafer W1, and the second substrate W2 is referred to as a second wafer W2. However, the present invention is not limited to the embodiments described below.

[0116] Figure 2 FIG is a diagram showing one embodiment of a grinding device. Figure 2 As shown, the grinding device includes: a substrate holding device 3 configured to hold the composite chip W and rotate it; a first grinding head 22A and a second grinding head 22B configured to grind the peripheral portion of the first chip W1 and form a recess in the peripheral portion of the composite chip W; and a motion control unit 10 that controls the motion of the substrate holding device 3 and the grinding heads 22A and 22B.

[0117] The substrate holding device 3 includes: a holding table 12 having a substrate holding surface 12 a for holding the composite wafer W; a table rotating device 15 for rotating the holding table 12 about the axis CL of the substrate holding surface 12 a; and a table shaft 17 fixed to the lower portion of the holding table 12 .

[0118] The holding table 12 has an opening 12b, such as a hole or groove, formed on the substrate holding surface 12a. The opening 12b is connected to a vacuum line 16. The holding table 12 may also have multiple openings 12b. When a composite wafer W is placed on the substrate holding surface 12a, a vacuum is created in the opening 12b via the vacuum line 16, and the composite wafer W is held on the substrate holding surface 12a by the vacuum.

[0119] The substrate holding surface 12a has the same contour as the composite wafer W. In this embodiment, the composite wafer W is circular, and the substrate holding surface 12a is also circular. The substrate holding surface 12a has the same size as the composite wafer W. In other words, the diameter of the substrate holding surface 12a is the same as the diameter of the composite wafer W. Therefore, the entire lower surface of the composite wafer W is held by the substrate holding surface 12a.

[0120] In one embodiment, the substrate holding surface 12 a may be smaller than the composite wafer W as long as it can support the peripheral edge portion of the composite wafer W. In one embodiment, the substrate holding surface 12 a may be larger than the composite wafer W.

[0121] The table rotating device 15 includes a motor and the like, and is connected to the table shaft 17. When the table rotating device 15 is driven, the holding table 12 and the table shaft 17 rotate integrally around the axis CL of the substrate holding surface 12a.

[0122] The composite wafer W is held on the substrate holding surface 12a so that the axis of the composite wafer W is aligned with the axis CL of the substrate holding surface 12a. Therefore, the composite wafer W and the holding table 12 rotate integrally about the axis of the composite wafer W (i.e., the axis CL of the substrate holding surface 12a).

[0123] The polishing apparatus includes a liquid supply nozzle 18 disposed above the substrate holding surface 12a. The liquid supply nozzle 18 is connected to a liquid supply line (not shown) and is configured to supply liquid such as pure water or functional water toward the center of the composite wafer W.

[0124] Functional water is an acidic liquid, alkaline liquid, ozone water, or fine bubble water containing water, etc. The liquid supplied to the center of the rotating composite wafer W spreads over the entire upper surface of the composite wafer W by centrifugal force, washing away grinding debris.

[0125] The polishing heads 22A and 22B respectively include: a pressing part 21 for pressing the polishing tapes T1 and T2, which are examples of polishing tools, respectively, to the peripheral portion of the composite chip W on the substrate holding surface 12a; and a moving actuator 23 for moving the pressing part 21 in a direction perpendicular to the substrate holding surface 12a.

[0126] In this embodiment, the polishing head 22A is a rough polishing head that supports a rough polishing tape T1 having abrasive grains on its surface. The polishing head 22B is a fine polishing head that supports a fine polishing tape T2 having abrasive grains smaller in diameter than those of the rough polishing tape T1 on its surface. Hereinafter, in this specification, the rough polishing tape T1 and the fine polishing tape T2 will not be specifically distinguished and may be simply referred to as the polishing tape T.

[0127] In the present embodiment, the first polishing head 22A and the second polishing head 22B have the same structure. Therefore, in this specification, the polishing heads 22A and 22B may be simply referred to as the polishing head 22 without being distinguished from each other.

[0128] The polishing head 22 is positioned above the outer periphery of the substrate holding surface 12a. The movable actuator 23 is held by a holding member such as a bracket (not shown). The specific structure of the movable actuator 23 is not particularly limited. As an example of the movable actuator 23, a combination of an air cylinder or a ball screw mechanism and a servo motor can be cited.

[0129] The polishing head 22 includes a feed reel 26 for feeding the polishing tape T, a take-up reel 27 for winding the polishing tape T, and a tape transport mechanism 30 for transporting the polishing tape T along its longitudinal direction (i.e., the transport direction). The moving actuator 23 is configured to integrally move the feed reel 26, the take-up reel 27, the pressing member 21, and the tape transport mechanism 30.

[0130] The pressing member 21 is disposed above the outer periphery of the substrate holding surface 12a. The pressing member 21 is located directly above the periphery of the composite wafer W held by the substrate holding surface 12a. The pressing member 21 supports the back side of the polishing tape T and presses the polishing surface (front side) of the polishing tape T against the periphery of the composite wafer W, thereby polishing the periphery of the first wafer W1.

[0131] The moving actuator 23 moves the pressing member 21 toward the peripheral edge of the composite wafer W. The pressing member 21 can press the polishing tape T toward the peripheral edge of the first wafer W1 by the movement.

[0132] The force (i.e., the polishing load) with which the pressing member 21 presses the polishing tape T toward the peripheral edge of the first wafer W1 can be adjusted by moving the actuator 23. The polishing tape T at the polishing point of the composite wafer W extends in the radial direction of the composite wafer W (i.e., the radial direction of the substrate holding surface 12a).

[0133] like Figure 2 As shown, the grinding head 22 includes a sensor target 32 ​​and a displacement sensor 33 disposed toward the sensor target 32. The sensor target 32 ​​can be moved integrally with the pressing member 21 by moving the actuator 23.

[0134] The displacement sensor 33 is configured to detect the movement distance of the sensor target 32, that is, the movement distance of the pressing member 21. Examples of the displacement sensor 33 include a contact-type displacement sensor and a non-contact-type displacement sensor.

[0135] The displacement sensor 33 is electrically connected to the motion control unit 10. The displacement sensor 33 detects a signal corresponding to the movement distance of the pressing member 21 during polishing of the peripheral portion of the first wafer W1. The movement distance of the pressing member 21 is the distance moved from the initial position of the pressing member 21 in a direction perpendicular to the substrate holding surface 12a. In one example, the initial position may be the position of the pressing member 21 when the pressing member 21 contacts the polishing tape T with the upper surface of the first wafer W1 while the composite wafer W is not rotating.

[0136] The motion control unit 10 includes a storage device 10a storing a program and a processing device 10b executing operations according to commands included in the program. The processing device 10b includes a CPU (Central Processing Unit) or a GPU (Graphics Processing Unit) executing operations according to commands included in the program stored in the storage device 10a.

[0137] The storage device 10a includes a main storage device (eg, random access memory) accessible to the processing device 10b and an auxiliary storage device (eg, a hard disk drive or a solid-state drive) storing data and programs. The motion control unit 10 is composed of at least one computer.

[0138] The displacement sensor 33 is configured to transmit a signal corresponding to the travel distance of the pressing member 21 to the motion control unit 10. The motion control unit 10 measures the travel distance of the pressing member 21 based on the signal transmitted from the displacement sensor 33 and determines the polishing endpoint of the first wafer W1 based on the measured travel distance. In this embodiment, the travel distance of the pressing member 21 corresponds to the travel distance of the polishing head 22.

[0139] Figure 3 (a) and Figure 3 (b) is a diagram showing a close-up guide roller actuator that moves the close-up guide roller. The polishing head 22 includes a close-up guide roller 36 and a close-up guide roller actuator 300. The close-up guide roller 36 is positioned upstream of and adjacent to the pressing member 21 in the conveyance direction of the polishing tape T. The close-up guide roller actuator 300 moves the close-up guide roller 36.

[0140] The tight front guide roller 36 supports the polishing tape T fed from the delivery reel 26 to the take-up reel 27. The pressing member 21 includes a pressing surface 21A parallel to the substrate holding surface 12a and an inclined surface 21B connected to the pressing surface 21A. The pressing surface 21A constitutes the bottom surface of the pressing member 21. The inclined surface 21B faces the axis CL of the substrate holding surface 12a and constitutes the inner surface of the pressing member 21.

[0141] The preceding guide roller 36 determines the relative position of the polishing tape T with respect to the inclined surface 21B of the pressing member 21. The preceding guide roller actuator 300 is configured to move the preceding guide roller 36 until the tape angle of the polishing tape T reaches a first angle θ1 and to move the preceding guide roller 36 until the tape angle reaches a second angle θ2.

[0142] The belt angle is defined as the angle formed by the polishing tape T in the area AR1 facing the pressing surface 21A and the polishing tape T in the area AR2 facing the inclined surface 21B. The area AR2 corresponds to the area between the immediate guide roller 36 and the inclined surface 21B of the pressing member 21 .

[0143] In this embodiment, the first angle θ1 is an acute angle, and the second angle θ2 is an obtuse angle. In one embodiment, the second angle θ2 may also be a right angle. That is, the second angle θ2 is a right angle or an obtuse angle.

[0144] A combination of a ball screw mechanism and a servo motor is one example of the immediate front guide roller actuator 300. For example, the immediate front guide roller 36 is connected to a ball screw mechanism (not shown) and is configured to be movable by the drive of a servo motor (not shown).

[0145] The motion control unit 10 is electrically connected to the immediately preceding guide roller actuator 300 and is configured to control the motion of the immediately preceding guide roller actuator 300. The motion control unit 10 operates the immediately preceding guide roller actuator 300 to move the immediately preceding guide roller 36 in the horizontal direction (i.e., parallel to the substrate holding surface 12a).

[0146] When the front guide roller actuator 300 moves the front guide roller 36 in a direction close to the pressing member 21 (ie, in a close direction), the front guide roller 36 moves the grinding tape T and sets the tape angle to the first angle θ1 (see FIG. Figure 3 (a)).

[0147] When the front guide roller actuator 300 moves the front guide roller 36 in a direction away from the pressing member 21 (ie, away direction), the front guide roller 36 moves the grinding tape T and sets the tape angle to the second angle θ2 (see FIG. Figure 3 (b) In this embodiment, the second angle θ2 is approximately within the range of 100 to 110 degrees.

[0148] The polishing head 22 has a rear guide roller 38 disposed on the downstream side of the pressing member 21 in the conveying direction of the polishing tape T. The tape conveying mechanism 30 is disposed on the downstream side of the rear guide roller 38 (see Figure 2 ).

[0149] The tape conveyor mechanism 30 is configured to convey the polishing tape T from the delivery reel 26 to the take-up reel 27 at a predetermined speed during polishing of the composite wafer W. In one embodiment, the polishing head 22 does not necessarily need to include the tape conveyor mechanism 30, but may be configured to convey the polishing tape T via a tensioning motor (not shown) coupled to the take-up reel 27.

[0150] The polishing head 22 includes a leading guide roller 37 that is disposed upstream of and adjacent to the preceding guide roller 36 in the conveyance direction of the polishing tape T. The leading guide roller 37 is disposed downstream of the delivery reel 26. Therefore, the polishing tape T extends from the delivery reel 26 to the take-up reel 27 via the leading guide roller 37, the preceding guide roller 36, the following guide roller 38, and the tape conveying mechanism 30 in this order.

[0151] Figure 4 (a) and Figure 4 (b) is a diagram showing a leading guide roller actuator for moving the leading guide roller. The polishing head 22 may include a leading guide roller actuator 301 for moving the leading guide roller 37.

[0152] The leading guide roller actuator 301 can have the same structure as the immediately preceding guide roller actuator 300. An example of the leading guide roller actuator 301 is a combination of a ball screw mechanism and a servo motor. For example, the leading guide roller 37 is coupled to a ball screw mechanism (not shown) and is configured to be movable by the drive of a servo motor (not shown).

[0153] The operation control unit 10 is electrically connected to the leading guide roller actuator 301 and is configured to control the operation of the leading guide roller actuator 301. The operation control unit 10 operates the leading guide roller actuator 301 to move the leading guide roller 37 in the horizontal direction.

[0154] After the immediately preceding guide roller actuator 300 operates the immediately preceding guide roller 36 and sets the belt angle to the second angle θ2 (see Figure 4 (a)), the leading guide roller actuator 301 moves the leading guide roller 37 in the direction of separation (refer to Figure 4 At this time, the immediate front guide roller actuator 300 moves the immediate front guide roller 36 to a position where the immediate front guide roller 36 does not contact the polishing tape T.

[0155] In this way, the leading guide roller 37 moves the polishing tape T to a third angle θ3, which is larger than the second angle θ2. The third angle θ3 is an obtuse angle and is larger than the second angle θ2. In this way, the leading guide roller actuator 301 can also move the leading guide roller 37 in the separating direction until the tape angle reaches the third angle θ3.

[0156] Figure 5 (a) to Figure 5 (d) is a diagram showing the polishing step of the first wafer. Figure 6 1 is a diagram showing a polishing process of a first wafer using a polishing apparatus. The first wafer W1 is polished as follows.

[0157] First, the composite wafer W is placed on the substrate holding surface 12a by a conveyor (not shown) so that its center is aligned with the axis CL of the substrate holding surface 12a. When the motion control unit 10 drives the stage rotating device 15, the stage rotating device 15 rotates the holding table 12 about the axis CL, and the composite wafer W rotates together with the holding table 12.

[0158] The liquid supply nozzle 18 supplies liquid to the center of the first wafer W1, forming a liquid film on the upper surface of the first wafer W1. When the motion control unit 10 drives the movement actuator 23, the movement actuator 23 moves the entire polishing head 22A including the pressing member 21 toward the first wafer W1.

[0159] The pressing member 21 presses the polishing surface of the rough polishing tape T1 toward the peripheral edge of the first wafer W1 (see Figure 5 (a) and Figure 6More specifically, the pressing member 21 presses the rough polishing tape T1 in the area AR1 against the peripheral edge of the first wafer W1.

[0160] At this time, the action control unit 10 moves the pressing member 21 in the depth direction of the composite wafer W while the belt angle is set to the first angle θ1 by the tight front guide roller actuator 300, thereby grinding the peripheral portion of the first wafer W1. The direction in which the pressing member 21 presses the rough grinding tape T1 against the peripheral portion of the first wafer W1 is perpendicular to the upper surface of the first wafer W1, which is equivalent to the depth direction of the composite wafer W (refer to Figure 5 (b)).

[0161] The periphery of the first wafer W1 is polished in the presence of liquid by relative movement between the rough polishing tape T1 and the first wafer W1. During polishing of the first wafer W1, the rough polishing tape T1 is conveyed at a predetermined speed in its conveying direction (ie, longitudinal direction).

[0162] During the polishing of the first wafer W1, the displacement sensor 33 detects a signal corresponding to the movement distance of the pressing member 21. The motion control unit 10 measures the movement distance of the pressing member 21 based on the signal sent from the displacement sensor 33. The motion control unit 10 determines the polishing end point as the moment when the movement distance of the pressing member 21 reaches a preset target value. In other words, the motion control unit 10 determines whether the polishing of the first wafer W1 is completed based on the signal obtained from the displacement sensor 33 (refer to Figure 6 Step S102).

[0163] If the operation control unit 10 determines that the polishing of the first wafer W1 is not completed (refer to "No" in step S102), the operation control unit 10 continues the polishing of the first wafer W1. On the other hand, if the operation control unit 10 determines that the polishing of the first wafer W1 is completed (refer to "Yes" in step S102), the operation control unit 10 ends the polishing of the first wafer W1. In this way, the polishing head 22A forms a recess 160 having a predetermined depth on the peripheral portion of the composite wafer W (refer to Figure 5 (c)).

[0164] In this embodiment, the motion control unit 10 determines the polishing endpoint of the first wafer W1 based on the signal sent from the displacement sensor 33. However, in one embodiment, the motion control unit 10 may determine the polishing endpoint of the first wafer W1 based on the polishing time. In this case, the motion control unit 10 determines the end of polishing of the first wafer W1 when a predetermined polishing time has elapsed.

[0165] Figure 7 This is a diagram showing the grinding boundary of the depression. Figure 7As shown, if a recess 160 is formed in the peripheral portion of the composite wafer W, a defect CH called a chip may be generated in the grinding boundary portion PB of the recess 160. The grinding boundary portion PB is defined as the boundary portion between the grinding area of ​​the first wafer W1 ground by the grinding head 22A and the unground area of ​​the first wafer W1 that is not ground.

[0166] After determining the polishing endpoint, the motion control unit 10 activates the motion actuator 23 of the polishing head 22A to move the polishing head 22A, including the pressing member 21, away from the first wafer W1. The motion control unit 10 then activates the motion actuator 23 of the polishing head 22B to move the entire polishing head 22B, including the pressing member 21, toward the first wafer W1.

[0167] At this time, the operation control unit 10 presses the finishing grinding tape T2 against the grinding boundary portion PB of the recess 160 (see FIG. 1 ), while operating the preceding guide roller actuator 300 and setting the tape angle to the second angle θ2. Figure 5 (d) and Figure 6 More specifically, the polishing head 22B presses the fine polishing tape T2 in the area AR2 against the polishing boundary portion PB.

[0168] The action control unit 10 can operate the front guide roller actuator 300 to determine the belt angle as the second angle θ2 after moving the grinding head 22B to the specified grinding position adjacent to the recess 160, or can move the grinding head 22B to the specified grinding position after determining the belt angle as the second angle θ2.

[0169] Figure 8 FIG is a diagram showing a polishing head that uses a polishing tape to remove debris. Figure 8 As shown, the polishing head 22B is configured to remove the chips CH by pressing the polishing tape T2 against the chips CH formed in the polishing boundary PB. In particular, by removing the chips CH with the polishing tape T2 in the area AR2, the polishing tape T2 can be prevented from being cut.

[0170] When the fine grinding tape T2 is moved in the depth direction of the composite wafer W and pressed against the chips CH in the region AR1, the fine grinding tape T2 may come into contact with the chips CH at the corners of the polishing boundary portion PB and be cut. In other words, the fine grinding tape T2 in the region AR1 may be sandwiched between the pressing surface 21A of the pressing member 21 and the chips CH in the polishing boundary portion PB and be cut.

[0171] In the present embodiment, the fine grinding tape T2 in the area AR2 is pressed against the chips CH, whereby the fine grinding tape T2 is elastically deformed toward the inclined surface 21B of the pressing member 21 .

[0172] More specifically, by pressing the fine grinding tape T2 against the debris CH while the tape angle is set at the second angle θ2, a gap is formed between the fine grinding tape T2 and the inclined surface 21B of the pressing member 21 in the region AR2. Consequently, the fine grinding tape T2 is elastically deformed toward the inclined surface 21B. This structure prevents the fine grinding tape T2 from being cut.

[0173] exist Figure 6 After step S103, the operation control unit 10 determines whether the polishing of the first wafer W1 is completed based on the polishing time required to remove the debris CH (ie, the debris removal time) (refer to Figure 6 Step S104).

[0174] When the operation control unit 10 determines that the debris removal time has not elapsed (see Figure 6 On the other hand, when the operation control unit 10 determines that the debris removal time has elapsed (refer to step S104 "No"), the debris CH is continued to be removed. Figure 6 "Yes" in step S104), it is determined that the removal of the debris CH is completed.

[0175] In one embodiment, the motion control unit 10 can operate the leading guide roller actuator 301 to set the belt angle to a third angle θ3, thereby additionally removing the debris CH. For example, if debris CH is formed over a wide radius of the composite wafer W in the grinding boundary portion PB, the motion control unit 10 can use the leading guide roller actuator 301 to move the leading guide roller 37 in the separating direction until the belt angle reaches the third angle θ3, thereby reliably removing the debris CH formed over a wide radius.

[0176] Figure 9 2 is a diagram showing another embodiment of the grinding device. In the above embodiment, the grinding heads 22A and 22B have the same structure, but Figure 9 In the illustrated embodiment, the grinding heads 22A, 22B have different structures.

[0177] like Figure 9 As shown, the polishing head 22A is configured to support the rough polishing tape T1 so that the tape angle becomes a first angle θ1, and the polishing head 22B is configured to support the fine polishing tape T2 so that the tape angle becomes a second angle θ2.

[0178] In this case, there is no need to change the angle of the belt between the first angle θ1 and the second angle θ2. Figure 9 In the illustrated embodiment, neither the grinding head 22A nor the grinding head 22B includes the immediately preceding guide roller actuator 300 (and the preceding guide roller actuator 301 ).

[0179] In this way, as long as the grinding device includes: a grinding head 22A that forms a recess 160 on the peripheral portion of the composite chip W; and a grinding head 22B that removes the debris CH formed in the recess 160, the grinding heads 22A and 22B do not necessarily have to include a preceding guide roller actuator 300 (and a preceding guide roller actuator 301).

[0180] Figure 10A 2 is a diagram showing another embodiment of the grinding device. In the above embodiment, the grinding device includes a plurality of grinding heads 22A and 22B. Figure 10A As shown, the grinding device may also include a grinding head 22 .

[0181] In the above embodiment, the polishing head 22A supports the rough polishing tape T1 for forming the recess 160 on the peripheral portion of the composite wafer W, and the polishing head 22B supports the fine polishing tape T2 for removing the debris CH formed in the recess 160 .

[0182] However, depending on the polishing conditions such as the type (e.g., hardness) of the composite wafer W to be polished, the polishing apparatus does not necessarily need to include multiple polishing heads 22A and 22B that respectively support the two types of polishing tapes T1 and T2, but may also include a single polishing head 22. In this case, the polishing apparatus is configured to operate the polishing head 22 to form a recess 160 on the peripheral edge of the composite wafer W and remove the debris CH formed in the recess 160.

[0183] Figure 10A The grinding head 22 in the embodiment shown has the same Figures 1 to 8 The grinding heads 22A and 22B have the same structure as described above. Therefore, the grinding head 22 has a pressing member 21, a preceding guide roller 36, and a preceding guide roller actuator 300. In one embodiment, the grinding head 22 may also have a preceding guide roller actuator 301 for moving the preceding guide roller 37 (see Figure 4 (b)).

[0184] Figure 10B FIG. 1 is a diagram showing another embodiment of the grinding device. Figure 10B As shown, the grinding apparatus may be configured to grind a single wafer W rather than a composite wafer W. In one embodiment, Figure 10B In the embodiment shown, the polishing device can also be configured to polish a composite wafer W, similarly to the above-described embodiment. Figures 2 to 10A In the illustrated embodiment, the grinding apparatus may also be configured to grind a single wafer W instead of a composite wafer W.

[0185] exist Figure 10BIn the embodiment shown, the grinding apparatus includes pressing members 210A and 210B having different shapes. Specifically, the grinding head 22A includes a pressing member 210A having a first angle θα as an acute angle. The grinding head 22B includes a pressing member 210B having a second angle θβ as an obtuse angle. Figure 10B In the illustrated embodiment, the second angle θβ is an obtuse angle, but may also be a right angle. Hereinafter, in this specification, the pressing members 210A and 210B may be simply referred to as the pressing member 210 without being particularly distinguished from each other.

[0186] Figure 10C : is a diagram showing a pressing member having a first angle. Figure 10C As shown, the pressing member 210A includes a pressing surface 210A-1 parallel to the substrate holding surface 12a and an inclined surface 210A-2 connected to the pressing surface 210A-1.

[0187] The first angle θα is the angle between the pressing surface 210A-1 and the inclined surface 210A-2. The polishing head 22A arranges the polishing tape T along the pressing surface 210A-1 and the inclined surface 210A-2, thereby setting the tape angle to the first angle θα.

[0188] Figure 10D : is a diagram showing a pressing member having a second angle. Figure 10D As shown, the pressing member 210B includes a pressing surface 210B-1 parallel to the substrate holding surface 12a and an inclined surface 210B-2 connected to the pressing surface 210B-1.

[0189] The second angle θβ is the angle between the pressing surface 210B-1 and the inclined surface 210B-2. The polishing head 22B arranges the polishing tape T along the pressing surface 210B-1 and the inclined surface 210B-2, thereby setting the tape angle to the second angle θβ.

[0190] With this structure, the grinding head 22 does not need to change the belt angle between the first angle θα and the second angle θβ. FIG. 10B to FIG. 10D In the illustrated embodiment, neither the grinding head 22A or 22B needs to include the immediately preceding guide roller actuator 300 (and the preceding guide roller actuator 301 ).

[0191] exist Figures 2 to 10A In the embodiment shown, the grinding tool is equivalent to the grinding belt T, but FIG. 10B to FIG. 10D In the illustrated embodiment, the grinding tool corresponds to the combination of the grinding tape T and the pressing member 210. Specifically, the grinding tool having the first angle θα corresponds to the combination of the grinding tape T and the pressing member 210A, and the grinding tool having the second angle θβ corresponds to the combination of the grinding tape T and the pressing member 210B.

[0192] Thus, in the above embodiment (refer to Figures 1 to 10D ), the polishing head 22A is configured to hold a polishing tool (polishing tape T, or a combination of a polishing tape T and a pressing member 210) having a first acute angle, and the polishing head 22A presses the polishing tool against the peripheral edge of a wafer W (a single wafer W or a composite wafer W) to form a recess in the peripheral edge. The polishing head 22B is configured to hold a polishing tool (polishing tape T) having a second right angle or an obtuse angle, and the polishing head 22B presses the polishing tool against the recessed polishing boundary PB.

[0193] In one embodiment, each of the grinding head 22A and the grinding head 22B can hold a grinding wheel instead of a grinding belt as a grinding tool. With such a structure, the grinding device can also remove debris. Below, the structure of the grinding device having a grinding head holding a grinding wheel is described with reference to the accompanying drawings.

[0194] Figure 11 : is a diagram showing another embodiment of the grinding device. Figure 11 In the illustrated embodiment, the grinding device is configured to grind a single wafer W, but may also be configured to grind a composite wafer W.

[0195] like Figure 11 As shown, the grinding head 22A is configured to hold a grinding wheel G1 as a grinding tool, which has a first angle of acute angle. The grinding head 22B is configured to hold a grinding wheel G2 as a grinding tool, which has a second angle of right angle or obtuse angle. Hereinafter, the grinding wheel G1 and the grinding wheel G2 will not be specifically distinguished and may be simply referred to as the grinding wheel G.

[0196] The grinding head 22A and the grinding head 22B each include a drive actuator RA that holds and rotates a grinding wheel G. The drive actuator RA is, for example, a motor and is held by the movement actuator 23 .

[0197] The drive actuator RA has a rotation axis RA-1 to which a grinding wheel G is fixed. When the drive actuator RA is driven, the grinding wheel G rotates about the rotation axis RA-1. By driving the moving actuator 23, the drive actuator RA and the grinding wheel G are lowered toward the periphery of the wafer W in the depth direction of the wafer W. By driving the drive actuator RA, the grinding wheel G rotates while contacting the periphery of the wafer W, thereby grinding (cutting, grinding) the periphery of the wafer W.

[0198] Figure 12 (a) is a diagram showing a grinding wheel having a tapered recess, Figure 12 (b) is a diagram showing a grinding wheel having a conical convex portion. Figure 12As shown in (a), the grinding wheel G1 includes a main body G1a fixed to the rotation axis RA-1 and a tapered recess G1b connected to the main body G1a. The main body G1a and the tapered recess G1b are integrally formed components.

[0199] The tapered recess G1b has a tapered shape extending toward the central axis CR of the rotation axis RA-1 and approaching the main body G1a, and has a first angle θa which is an acute angle. Figure 12 In (a), the tapered recess G1b has a mortar shape having a flat surface portion. However, as long as the first angle θa can be formed, the tapered recess G1b may have a mortar shape having no flat surface portion.

[0200] like Figure 12 As shown in (b), the grinding wheel G2 includes a main body G2a fixed to the rotation axis RA-1 and a tapered convex portion G2b connected to the main body G2a. The main body G2a and the tapered convex portion G2b are integrally formed components.

[0201] The tapered convex portion G2b has a tapered shape extending toward the central axis CR of the rotation axis RA-1 and away from the main body portion G2a, and has a second obtuse angle θb. The second angle θb may be a right angle. Figure 12 In (b), the tapered convex portion G2b has a truncated cone shape, but the tapered convex portion G2b may have a conical shape as long as the second angle θb can be formed.

[0202] Figure 13 (a) to Figure 13 (c) is a diagram showing the polishing process of the peripheral portion of the wafer. Figure 13 As shown in (a), the action control unit 10 (refer to Figure 11 ) By driving the moving actuator 23, the grinding wheel G1 (and the driving actuator RA) is lowered to press the grinding wheel G1 against the peripheral edge of the wafer W. At this time, the grinding wheel G1 is rotated by the driving actuator RA of the polishing head 22A.

[0203] The grinding head 22A continues to grind the peripheral edge of the wafer W using the grinding wheel G1, and forms a recess 160 having a predetermined depth in the peripheral edge of the wafer W (see FIG. Figure 13 Then, the motion control unit 10 drives the moving actuator 23 to separate the grinding wheel G1 from the peripheral edge of the wafer W.

[0204] Furthermore, the operation control unit 10 drives the moving actuator 23 to press the grinding wheel G2 against the grinding boundary portion PB of the recess 160 (see Figure 13(c)). At this time, the grinding wheel G2 is rotated by the driving actuator RA of the grinding head 22B. The grinding head 22B can remove the chips CH by pressing the grinding wheel G2 against the chips CH formed in the grinding boundary portion PB.

[0205] Figure 14 (a) and Figure 14 (b) is a diagram showing the manufacturing process of the composite wafer. Figure 14 As shown in (a), the first wafer W1 has the recess 160 from which the debris CH has been removed. The composite wafer W is manufactured by bonding the first wafer W1 and the second wafer W2.

[0206] When the first wafer W1 and the second wafer W2 are bonded, the device layer 200 formed on the first wafer W1 is placed opposite to the second wafer W2. Then, the back side of the first wafer W1 (i.e., the side where the device layer 200 is not formed) is polished by a predetermined amount (see Figure 14 (b)).

[0207] As shown in the above embodiment, the polishing apparatus includes a first polishing head 22A that holds a first polishing tool (a polishing tape or grinding wheel) having a first acute angle, and a second polishing head 22B that holds a second polishing tool (a polishing tape or grinding wheel) having a second right or obtuse angle. Thus, the polishing apparatus can form a recess 160 on the periphery of a wafer W (a single wafer W or a composite wafer W) and remove debris CH formed on the polishing boundary PB of the recess 160.

[0208] The above embodiments can be combined as appropriate. For example, the grinding device can include a grinding head that holds a grinding belt and a grinding head that holds a grinding wheel. With such a structure, the grinding device can also remove debris CH.

[0209] For example, the grinding device may also have Figure 11 The grinding head 22A and Figures 2 to 9 (or Figure 10B ) is a grinding head 22B of the embodiment shown in FIG. In this case, the grinding head 22A holds a grinding wheel G1 as a grinding tool. The grinding head 22B holds a grinding tape T2 (or a combination of the grinding tape T2 and the pressing member 210B) as a grinding tool.

[0210] The grinding wheel G1 can grind the wafer W earlier than the grinding tape T1, thus shortening the grinding time. In this case, when the wafer W is ground by the grinding wheel G1 held by the grinding head 22A, the surface of the recess 160 becomes rough after grinding.

[0211] Therefore, by finish-polishing the recess 160 of the wafer W using the polishing tape T2 (or a combination of the polishing tape T2 and the pressing member 210B) held by the polishing head 22B, the surface flatness of the recess 160 can be improved. In other words, with this configuration, the polishing apparatus can shorten the polishing time and improve the surface flatness of the recess 160.

[0212] The above embodiments are described with the goal of enabling those with ordinary skill in the technical field to which the present invention pertains to carrying out the present invention. Those skilled in the art will readily be able to devise various modifications of the above embodiments, and the technical concepts of the present invention are also applicable to other embodiments. Therefore, the present invention is not limited to the described embodiments but should be interpreted in its broadest scope consistent with the technical concepts defined by the scope of the claims.

Claims

1. A grinding device, characterized in that: have: a first grinding head holding a first grinding tool having a first angle, the first angle being an acute angle; as well as a second grinding head holding a second grinding tool having a second angle, the second angle being a right angle or an obtuse angle; The first polishing head presses the first polishing tool against the peripheral edge of the substrate to form a recess in the peripheral edge; The second grinding head presses the second grinding tool against the grinding boundary portion of the recess.

2. The grinding device according to claim 1, characterized in that The first polishing head corresponds to a rough polishing head that presses a rough polishing tape as the first polishing tool against the peripheral portion to form a depression in the peripheral portion. The second polishing head corresponds to a polishing head that presses a polishing tape as the second polishing tool against the polishing boundary portion. The rough polishing head supports the rough polishing tape so that the tape angle of the rough polishing tape becomes the first angle. The fine grinding head supports the fine grinding tape so that the tape angle of the fine grinding tape becomes the second angle.

3. The grinding device according to claim 2, characterized in that The rough grinding head and the fine grinding head each have; a pressing member for pressing the rough grinding tape and the fine grinding tape toward the peripheral portion, respectively; a front guide roller, arranged upstream of the pressing member and adjacent to the pressing member in the conveying direction of the rough grinding tape and the fine grinding tape; as well as A close-front guide roller actuator moves the close-front guide roller.

4. The grinding device according to claim 3, characterized in that The immediately preceding guide roller actuator is configured to move the immediately preceding guide roller in an approaching direction toward the pressing member and in a separating direction away from the pressing member.

5. The grinding device according to claim 3, characterized in that The grinding device includes an operation control unit for controlling the operation of the immediate front guide roller actuator. The operation control unit operates the front guide roller actuator to move the front guide roller until the belt angle of the rough grinding belt reaches the first angle. The operation control unit operates the immediate-front guide roller actuator to move the immediate-front guide roller until the belt angle of the fine grinding belt reaches the second angle.

6. The grinding device according to claim 5, characterized in that The operation control unit operates the front guide roller actuator to adjust the belt angle to the first angle, and moves the rough grinding belt in the depth direction of the substrate to form a recess of a predetermined depth in the peripheral portion. The operation control unit operates the immediate guide roller actuator to adjust the belt angle to the second angle, thereby pressing the fine grinding belt against the grinding boundary portion.

7. The grinding device according to claim 6, characterized in that The operation control unit operates the immediate preceding guide roller actuator to press the fine grinding tape in a region between the immediate preceding guide roller and the pressing member against the grinding boundary portion.

8. The grinding device according to claim 3, characterized in that The rough grinding head and the fine grinding head each have: a leading guide roller, arranged upstream of the preceding guide roller in the conveying direction of the rough grinding belt and the fine grinding belt, and arranged adjacent to the preceding guide roller; as well as a leading guide roller actuator for moving the leading guide roller, The preceding guide roller actuator moves the preceding guide roller until the preceding guide roller reaches a third angle that is larger than the second angle.

9. The grinding device according to claim 8, characterized in that The grinding device includes an operation control unit for controlling the operation of the leading guide roller actuator. The operation control unit operates the preceding guide roller actuator to press the finishing grinding tape against the grinding boundary portion, and then operates the preceding guide roller actuator to move the preceding guide roller until the belt angle reaches the third angle.

10. The grinding device according to claim 1, characterized in that The first grinding head holds a first grinding wheel as the first grinding tool, The second grinding head holds a second grinding wheel as the second grinding tool, The first grinding wheel has a conical recess forming the first angle, The second grinding wheel has a tapered convex portion forming the second angle.

11. A grinding method, characterized in that: A first grinding tool having a first angle is pressed against the peripheral edge of the substrate by a first grinding head to form a recess in the peripheral edge, wherein the first angle is an acute angle. A second grinding tool having a second angle is pressed against the grinding boundary portion of the recess by a second grinding head, wherein the second angle is a right angle or an obtuse angle.

12. The grinding method according to claim 11, characterized in that The first polishing head corresponds to a rough polishing head that presses a rough polishing tape as the first polishing tool against the peripheral portion to form a depression in the peripheral portion. The second polishing head corresponds to a polishing head that presses a polishing tape as the second polishing tool against the polishing boundary portion. The rough grinding tape is set at the first angle, and the rough grinding tape is pressed against the peripheral portion to form a depression in the peripheral portion. The tape angle of the fine grinding tape is set to the second angle, and the fine grinding tape is pressed against the grinding boundary portion.

13. The grinding method according to claim 12, characterized in that: In the conveying direction of each of the rough grinding tape and the fine grinding tape, a preceding guide roller arranged upstream of and adjacent to the pressing member is operated to adjust the tape angle to the first angle. The front guide roller is operated to adjust the belt angle to the second angle.

14. The grinding method according to claim 13, characterized in that: In the conveying directions of the rough grinding tape and the fine grinding tape, a preceding guide roller arranged upstream of and adjacent to the preceding guide roller is operated to set the belt angle to a third angle larger than the second angle.

15. The grinding method according to claim 11, wherein: The first grinding head holds a first grinding wheel as the first grinding tool, The second grinding head holds a second grinding wheel as the second grinding tool, pressing the first grinding wheel having the tapered recessed portion forming the first angle against the peripheral portion to form a recess in the peripheral portion; The second grinding wheel having the tapered convex portion forming the second angle is pressed against the grinding boundary portion.

16. A grinding head, characterized in that: The grinding head comprises: a pressing member for pressing the grinding tape toward the peripheral portion; a front guide roller arranged upstream of the pressing member in the conveying direction of the polishing tape and adjacent to the pressing member; and a close-front guide roller actuator that moves the close-front guide roller, The front guide roller actuator moves the front guide roller until the belt angle of the grinding belt becomes a first angle, which is an acute angle. The immediate front guide roller actuator moves the immediate front guide roller until the belt angle becomes a second angle, which is a right angle or an obtuse angle.

17. The grinding head according to claim 16, characterized in that The immediately preceding guide roller actuator is configured to move the immediately preceding guide roller in an approaching direction toward the pressing member and in a separating direction away from the pressing member.

18. The grinding head according to claim 16, wherein: The polishing head moves the polishing tape in the depth direction of the substrate to form a recess of a predetermined depth in the peripheral portion while the tape angle is set to the first angle by the front guide roller actuator. The polishing head adjusts the belt angle to a second angle by the immediate guide roller actuator, thereby pressing the polishing belt against the concave polishing boundary portion.

19. The grinding head according to claim 16, wherein: The grinding head comprises: a preceding guide roller disposed upstream of and adjacent to the immediately preceding guide roller in the conveying direction of the grinding tape; and a leading guide roller actuator for moving the leading guide roller, The leading guide roller actuator moves the leading guide roller until the belt angle reaches a third angle greater than the second angle.

Images