Substrate processing method and substrate processing device

Abstract

According to the present invention, a substrate processing method for processing a bonded substrate produced by bonding a first substrate and a second substrate involves using a first holding unit to suction and hold the first substrate, using a second holding unit to suction and hold the second substrate, and causing relative displacement between the first holding unit and the second holding unit so as to apply stress to the first substrate and the second substrate in a substantial rotational symmetry direction with respect to the centers of the first substrate and the second substrate.

Description

Substrate processing method and substrate processing apparatus

[0001] This disclosure relates to a substrate processing method and a substrate processing apparatus.

[0002] Patent Document 1 describes a peeling device having a first holding part that holds a first substrate among the polymerization substrates, and a second holding part that has a plurality of adsorption moving parts that hold a second substrate among the polymerization substrates, wherein the second holding part is moved in a direction that separates the second substrate from the surface of the first substrate.

[0003] Japanese Patent Application Publication No. 2016-027671

[0004] The technology described herein appropriately separates the first substrate and the second substrate in a polymerized substrate in which a first substrate and a second substrate are joined.

[0005] One aspect of the present disclosure is a substrate processing method for processing a polymerized substrate in which a first substrate and a second substrate are joined, comprising: adsorbing and holding the first substrate with a first holding portion; adsorbing and holding the second substrate with a second holding portion; and applying a stress to the first substrate and the second substrate in a direction substantially rotationally symmetric with respect to the centers of the first substrate and the second substrate by relatively displacing the first holding portion and the second holding portion.

[0006] According to this disclosure, in a polymerized substrate in which a first substrate and a second substrate are joined, the first substrate and the second substrate can be appropriately separated.

[0007] This is a side view showing an outline of the configuration of the polymerized wafer to be processed. This is a plan view showing an outline of the configuration of the wafer processing system according to this embodiment. This is a side view showing an outline of the configuration of the peeling device. This is a plan view showing an outline of the configuration of the second holding unit and an example of the adsorption state to the polymerized wafer. This is a flow chart showing the main steps of wafer processing. This is a flow chart showing the main steps of peeling processing. This is a side view showing an example of the time-series state of the peeling device in the main steps of peeling processing. This is a plan view showing an example of the formation state of peeling base points on the polymerized wafer. This is a plan view showing another example of the formation state of peeling base points on the polymerized wafer. This is a plan view showing an outline of an example of the adsorption state of the second holding unit to the polymerized wafer. This is a side view showing an example of the state of the peeling device in the main steps of peeling processing. This is a side view showing an example of the time-series state of the peeling device in the main steps of peeling processing. This is a side view showing an outline of the configuration of the peeling device according to a modified example. This is a side view showing an example of the state of the peeling device according to a modified example. This is a side view showing an example of the state of the peeling device according to a modified example.

[0008] Hereinafter, a wafer processing system equipped with a stripping device as a substrate processing apparatus according to this embodiment, and a wafer processing method as a substrate processing method, will be described with reference to the drawings. In this specification and drawings, elements having substantially the same functional configuration are denoted by the same reference numerals, and redundant explanations will be omitted.

[0009] In the wafer processing system 1 described later according to this embodiment, processing is performed on a polymerized wafer T, which is a polymerized substrate formed by bonding a first wafer W, which is a first substrate, and a second wafer S, which is a second substrate, as shown in Figure 1. Hereinafter, in the first wafer W, the side that is bonded to the second wafer S will be called the surface Wa, and the side opposite to the surface Wa will be called the back surface Wb. Similarly, in the second wafer S, the side that is bonded to the first wafer W will be called the surface Sa, and the side opposite to the surface Sa will be called the back surface Sb.

[0010] The first wafer W is a semiconductor wafer such as a silicon substrate, and at least one film is formed on the surface Wa side by lamination. Hereinafter, the film formed on the surface Wa side may be referred to as the "laminated film". In this embodiment, the laminated film includes a device layer Dw and a bonding layer Fw, and is laminated in this order from the surface Wa side. The device layer Dw includes multiple devices. The bonding layer Fw may be, for example, an oxide film (THOX film, SiO ２ Examples include films, TEOS films, SiC films, SiCN films, or adhesives. The first wafer W is bonded to the second wafer S via this bonding layer Fw. Note that the device layer Dw and bonding layer Fw may not be formed on the surface Wa.

[0011] The second wafer S is a semiconductor wafer such as a silicon substrate, and at least one film is laminated on the surface Sa side. Hereinafter, the film formed on this surface Sa side may be referred to as the "laminated film". In this embodiment, the laminated film includes a laser absorption layer P, a device layer Ds, and a bonding layer Fs, and is laminated in this order from the surface Sa side. The laser absorption layer P absorbs laser light irradiated from a laser irradiation unit (not shown). The laser absorption layer P includes, for example, an oxide film (SiO ２ A film (TEOS film) is used, but it is not particularly limited as long as it absorbs laser light. The device layer Ds and bonding layer Fs are the same as the device layer Dw and bonding layer Fw of the first wafer W, respectively. The bonding layer Fs of the second wafer S and the bonding layer Fw of the first wafer W are then bonded together. Note that the device layer Ds and bonding layer Fs may not be formed on the surface Sa. In this case, the laser absorption layer P is formed on the first wafer W side, and the device layer Dw on the first wafer W side is transferred to the second wafer S side.

[0012] As shown in Figure 2, the wafer processing system 1 has a configuration in which an loading / unloading station 2 and a processing station 3 are integrally connected. At the loading / unloading station 2, for example, a hoop F capable of accommodating multiple polymerized wafers T, multiple first wafers W, or multiple second wafers S is loaded and unloaded to and from the outside. The processing station 3 is equipped with various processing devices for performing desired processing on the polymerized wafers T, first wafers W, or second wafers S.

[0013] The loading / unloading station 2 is equipped with a hoop mounting table 10 on which multiple hoops F, for example, three hoops F, are placed. A wafer transport device 20 is also provided on the positive X-axis side of the hoop mounting table 10. The wafer transport device 20 moves along a transport path 21 extending in the Y-axis direction and is configured to transport the superimposed wafer T, the first wafer W, or the second wafer S between the hoops F on the hoop mounting table 10 and the transition stage 30 and inversion device 31, which will be described later.

[0014] At the loading / unloading station 2, a transition stage 30 and an inversion device 31 are stacked on the positive X-axis side of the wafer transport device 20. The transition stage 30 temporarily stores the polymerized wafer T, the first wafer W, or the second wafer S for transfer to and from the processing station 3. The inversion device 31 inverts the front and back surfaces of the second wafer S. Note that the number and arrangement of the transition stages 30 and inversion devices 31 are not limited to this embodiment and can be determined arbitrarily.

[0015] The processing station 3 is equipped with a wafer transfer device 40, a laser irradiation device 50, a peeling device 60, and a cleaning device 70. The wafer transfer device 40 is positioned on the positive X-axis side of the transition stage 30 and the inversion device 31. The two laser irradiation devices 50 are positioned on the positive Y-axis side of the wafer transfer device 40, while the peeling device 60 and the cleaning device 70 are positioned on the negative Y-axis side of the wafer transfer device 40. Note that the number and arrangement of the laser irradiation devices 50, peeling devices 60, and cleaning devices 70 are not limited to this embodiment and can be determined arbitrarily.

[0016] The wafer transport device 40 is configured to move freely along a transport path 41 extending in the X-axis direction, and is capable of transporting the polymerized wafer T, the first wafer W, or the second wafer S to the transition stage 30, the inversion device 31, the laser irradiation device 50, the peeling device 60, and the cleaning device 70.

[0017] The laser irradiation device 50 emits laser light (e.g., CO) into the inside of the polymerized wafer T, more specifically into the laser absorption layer P formed on the surface Sa of the second wafer S. ２The bonding strength at the interface between the second wafer S and the laser absorption layer P is reduced by irradiating it with a laser. In the following description, the interface where the bonding strength has been reduced by this laser irradiation may be referred to as the "delamination surface". In one embodiment, other layers (not shown) may be provided as layers adjacent to the laser absorption layer P of the second wafer S. If the bonding strength at the interface between the second wafer S and the other layer, the interface between the laser absorption layer P and the other layer, or the interface between the device layer Ds and the other layer is reduced by irradiating the laser absorption layer P with laser light, the delamination surface may be that interface. The laser irradiation device 50 has a control device 51 which will be described later.

[0018] The peeling device 60 peels the second wafer S from the first wafer W in the polymerized wafer T, using the peeling surface, where the bonding strength has been reduced by the laser irradiation device 50, as a starting point. The peeling device 60 has a control device 61, which will be described later. The configuration of the peeling device 60 will be described later.

[0019] The cleaning device 70 cleans the first wafer W and the second wafer S that have been peeled off by the peeling device 60. The configuration of the cleaning device 70 is not particularly limited.

[0020] In this embodiment, the explanation will be given using the example of a case where only one cleaning device 70 common to both the first wafer W and the second wafer S is provided in the wafer processing system 1. However, a first cleaning device for cleaning the first wafer W and a second cleaning device for cleaning the second wafer S may be provided independently in the wafer processing system 1.

[0021] The wafer processing system 1 described above is equipped with a control device 51, a control device 61, and at least one control device 80. The control device 51 individually controls the operation of the laser irradiation device 50. The control device 61 individually controls the operation of the peeling device 60. The control device 80 oversees the control of the series of wafer processing operations in the wafer processing system 1.

[0022] Control devices 51, 61, and 80 each process computer-executable instructions causing the laser irradiation device 50, the peeling device 60, and the wafer processing system 1 to perform the various processes described herein. Control devices 51, 61, and 80 can each be configured to control the elements of the laser irradiation device 50, the peeling device 60, and the wafer processing system 1 to perform the various processes described herein. In one embodiment, some or all of control device 51 may be included in the laser irradiation device 50, some or all of control device 61 may be included in the peeling device 60, and some or all of control device 80 may be included in the wafer processing system 1.

[0023] Control devices 51, 61, and 80 are each implemented, for example, by a computer. Control devices 51, 61, and 80 may each be one or more circuits, and may be provided as a single unit or in separate parts. Control devices 51, 61, and 80 may each include a processing unit, a storage unit, and a communication interface. The functions realized by the processing units described in this disclosure may be implemented in circuits or processing circuits, including general-purpose processors, application-specific processors, integrated circuits, ASICs (Application Specific Integrated Circuits), CPUs (Central Processing Units), conventional circuits, and / or combinations thereof, programmed to realize the functions described. A processor is considered to be a circuit or processing circuit, including transistors and other circuits. A processor may be a programmed processor that executes a program stored in memory. This program (computer program product) may be stored in memory beforehand or may be retrieved via a medium when needed. The medium may be various computer-readable storage media, such as memory cards, optical discs, HDDs (Hard Disk Drives), or other removable storage media, and the program may be provided in a form stored on such storage media. Alternatively, the medium may be a communication line connected to a communication interface, and the program may be distributed by a remote server device or the like. The acquired program is stored in the storage unit and read from the storage unit and executed by the processing unit.The memory unit may include storage media such as RAM (Random Access Memory), ROM (Read Only Memory), EEPROM (Electrically Erasable Programmable Read Only Memory), HDD (Hard Disk Drive), SSD (Solid State Drive), or a combination thereof. The communication interface may communicate with the laser irradiation device 50, the peeling device 60, and the wafer processing system 1 via a communication line such as a LAN (Local Area Network). In this disclosure, circuits, units, and means are hardware programmed to realize or configured to perform the functions described. The hardware may be any hardware described in this disclosure, or any hardware known to be programmed to perform or execute the functions described. If the hardware is a processor that is considered to be a type of circuit, the circuit, means, or unit is a combination of the hardware and the software used to constitute the hardware and / or processor.

[0024] In this embodiment, the control devices 51 and 61 are installed separately for the laser irradiation device 50 and the peeling device 60, respectively. However, these control devices 51 and 61 may be configured as an integral part of the control device 80. In other words, the operation of the laser irradiation device 50 and the peeling device 60 may be controlled by the control device 80.

[0025] Next, the peeling device 60 described above will be explained. As shown in Figure 3, the peeling device 60 according to this embodiment includes a first holding part 101 and a second holding part 102.

[0026] The first holding portion 101 includes a holding surface 101a that holds the first wafer W in contact with the back surface Wb of the first wafer W in the superimposed wafer T. In the state example shown in FIG. 3, the back surface Wb of the first wafer W in the superimposed wafer T is held by the holding surface 101a of the first holding portion 101. The holding means in the first holding portion 101 is not particularly limited, and electrostatic adsorption, vacuum adsorption or the like can be used.

[0027] A motor 110 is provided in the first holding portion 101, and as shown by the curved arrow in FIG. 3, the first holding portion 101 is configured to be rotatable about the central axis ψ of the first holding portion 101 by the motor 110. The rotation of the first holding portion 101 allows at least the first wafer W held on the holding surface 101a to rotate. The motor 110 is an example of a rotation mechanism serving as the displacement mechanism of the present disclosure.

[0028] The motor 110 may be controlled by, for example, the control device 61 or the control device 80 such that the rotation angle of the first holding portion 101 becomes a desired one. Further, the torque, rotation amount and the like of the motor 110 may be monitored by the control device 61 or the control device 80.

[0029] The second holding portion 102 includes a suction portion 111. The suction portion 111 is in contact with the back surface Sb of the second wafer S in the superimposed wafer T and sucks the second wafer S. In the state example shown in FIG. 3, the back surface Sb of the second wafer S is sucked by the plurality of suction portions 111 of the second holding portion 102. A plurality of suction portions 111 may be provided as shown in FIG. 3. The suction method for the second wafer S by the suction portion 111 is not particularly limited. For example, the suction portion 111 may suck the second wafer S by frictional force, or may evacuate the second wafer S to perform vacuum suction. In one embodiment, the suction portion 111 is provided with a suction path connected to a suction source (not shown). The contact portion between the suction portion 111 and the second wafer S is preferably formed of an elastic member.

[0030] As shown in FIG. 4, the suction portions 111 may be arranged substantially rotationally symmetrically with respect to the center 102c of the second holding portion 102 in a plan view. In the example shown in FIG. 4, one suction portion 111 (hereinafter referred to as "inner suction portion 111c") is provided at a position close to the center 102c of the second holding portion 102. Further, eight suction portions 111 (hereinafter referred to as "outer suction portions 111e") are provided on one circumference at a position close to the outer periphery 102e of the second holding portion 102. However, the arrangement and number of the plurality of suction portions 111 are not limited thereto. Two or more inner suction portions 111c may be provided on one or more concentric circumferences at positions close to the center 102c of the second holding portion 102. Further, seven or less, or nine or more outer suction portions 111e may be provided on one or more concentric circumferences on the side close to the outer periphery 102e of the second holding portion 102. In addition, although the suction portions 111 are provided in two stages (the inner suction portion 111c and the outer suction portion 111e) in the radial direction of the second holding portion 102, the present invention is not limited thereto, and the suction portions 111 may be provided in three or more stages in the radial direction of the second holding portion 102.

[0031] Each of the suction portions 111 may be configured to be moved in the vertical direction individually or collectively. Each of the suction portions 111 is moved in the vertical direction by an elevating mechanism 120 as shown in FIG. 3. The elevating mechanism 120 is an example of the displacement mechanism of the present disclosure.

[0032] The elevating mechanism 120 includes an outer moving portion 121e and an inner moving portion 121c. The outer moving portion 121e and the inner moving portion 121c are each supported by a base portion 130. The base portion 130 may, for example, be attached to and supported by a ceiling portion (not shown) of the peeling device 60.

[0033] The outer moving portions 121e are provided in the same number as the outer suction portions 111e at positions corresponding to the outer suction portions 111e. Similarly, the inner moving portions 121c are provided in the same number as the inner suction portions 111c at positions corresponding to the inner suction portions 111c. The outer moving portion 121e and the inner moving portion 121c are configured to independently move the suction portions 111e and 111c in the vertical direction, respectively, and can move the suction portions in a direction away from the first holding portion 101, that is, upward in the present embodiment, for example.

[0034] The outer movable part 121e comprises a support member 131 and a drive unit 132. One end of the support member 131 is connected to the outer suction part 111e, and the other end is connected to the drive unit 132 via the base part 130. The drive unit 132 moves the support member 131, which is connected to the lower part, in the vertical direction. The drive unit 132 is also provided on the base part 130. The configuration of the drive unit 132 is not particularly limited, and in one embodiment, a motor or an air-driven cylinder may be used as the drive unit 132.

[0035] The external moving part 121e moves the support member 131 upward using the drive unit 132, thereby pulling up the external suction part 111e of the second holding part 102 connected to the support member 131. This moves the external suction part 111e upward. Furthermore, since the external moving parts 121e are provided in accordance with the position and number of external suction parts 111e, multiple external suction parts 111e can be moved individually.

[0036] The inner moving part 121c comprises a support member 141 and a drive unit 142. One end of the support member 141 is connected to the inner suction part 111c, and the other end is connected to the drive unit 142 via the base part 130. The drive unit 142 moves the support member 141, which is connected to the lower part, in the vertical direction. The drive unit 142 is also provided on the base part 130. Similar to the outer moving part 121e, the inner moving part 121c pulls up the inner moving part 121c of the second holding part 102 connected to the support member 141 by moving the support member 141 upward using the drive unit 142.

[0037] The lifting mechanism 120 may also be equipped with a force gauge (not shown) for measuring the load applied to the lifting mechanism 120.

[0038] The peeling apparatus 60 includes a blade 150. The blade 150 is configured to be movable so as to be inserted into at least one location on the periphery of the interface between the first wafer W and the second wafer S, for example, the peeling surface. The blade 150 forms peeling base points on the peeling surfaces of the first wafer W and the second wafer S, as will be described later, and constitutes the base point forming portion in this disclosure.

[0039] In one embodiment, the base point forming unit in this disclosure includes a moving mechanism 151 that holds the blade 150 so that it can move at least horizontally. The base point forming unit also includes a sensor 152 that detects the horizontal position or horizontal pressure of the blade 150 with respect to the peeling surfaces of the first wafer W and the second wafer S that the blade 150 contacts. The horizontal position or pressure of the blade 150 detected by the sensor 152 is output to a control device 61 or a control device 80. Furthermore, the control device 61 or the control device 80 controls the moving mechanism 151 based on the horizontal position or pressure of the blade 150 to adjust the horizontal position of the blade 150 so that peeling base points are formed on the peeling surface at a desired radial depth. In one embodiment, when peeling base points are formed around the entire circumference of the peeling surface, the control device 61 controls the moving mechanism 151 to adjust the horizontal position of the blade 150 so that the radial depth of the peeling base points is uniform around the entire circumference.

[0040] The base point forming section is not limited to the above embodiment equipped with a blade 150, and any desired configuration capable of forming a peeling base point A on the periphery of the peeling surface can be adopted.

[0041] For example, the peeling apparatus 60 may be equipped with an air cutter (not shown) as a base point forming unit. The air cutter supplies air to the interface between the first wafer W and the second wafer S to form a peeling base point A. To facilitate the formation of the peeling base point A, pressurized high-pressure air or heated high-temperature air may be used. Alternatively, a water cutter that supplies water to the interface between the first wafer W and the second wafer S may be used instead of the air cutter. The water supplied from the water cutter may be pressurized high-pressure water or heated high-temperature water.

[0042] For example, the peeling device 60 may also include an ultrasonic oscillator (not shown) that applies ultrasonic vibrations to the blade 150, which serves as the base point forming section.

[0043] Alternatively, the peeling apparatus 60 may also include a rotary cutter (not shown) as a base point forming unit. The rotary cutter has a configuration in which the cutter is rotated by, for example, a motor (not shown). In this case, the rotary cutter is inserted into the interface between the first wafer W and the second wafer S while rotating to form a peeling base point A.

[0044] For example, the peeling apparatus 60 may also include a heating unit (not shown) as a base point forming unit. The heating unit heats the interface between the first wafer W and the second wafer S to expand the first wafer W and the second wafer S, and applies thermal stress to the interface to form a peeling base point A.

[0045] Furthermore, for example, the peeling apparatus 60 may be provided with a suction mechanism 210 below the base point forming part such as the blade 150, as shown in Figure 3. The suction mechanism 210 is connected to a suction source (not shown) and sucks up the atmosphere near the peeling base point A. In St102, which will be described later, when the blade 150 is inserted at the interface between the first wafer W and the second wafer S to form the peeling base point A, particles may be generated. The suction mechanism 210 can suck up and remove these particles, keeping the inside of the peeling apparatus 60 clean. Also, a downflow may be formed inside the peeling apparatus 60, in which case, by placing the suction mechanism 210 below the blade 150, the suction mechanism 210 can suck up particles even more efficiently.

[0046] In one embodiment, the lifting mechanism 120 moves the multiple suction parts 111 of the second holding part 102 in the vertical direction, but the first holding part 101 and the second holding part 102 may be moved relative to each other. For example, the first holding part 101 may be provided with a lifting mechanism (not shown) to move the first holding part 101 in the vertical direction. Alternatively, for example, the lifting mechanism 120 may move the multiple suction parts 111 of the second holding part 102 in the vertical direction, and the lifting mechanism may also move the first holding part 101 upward.

[0047] In one embodiment, the second holding portion 102 may be configured to rotate around a central axis ψ. In this case, the rotation mechanism of the second holding portion 102 may be the same as that of the motor 110 provided on the first holding portion 101. In another embodiment, the second holding portion 102 may be configured to be rotatable, while the first holding portion 101 may be configured not to rotate.

[0048] In another embodiment, the device layer Dw on the first wafer W side can be transferred to the second wafer S side. In this case, the holding surface 101a of the first holding portion 101 holds the back surface Sb of the second wafer S on the polymerized wafer T, and the plurality of adsorption portions 111 of the second holding portion 102 hold the back surface Wb of the first wafer W on the polymerized wafer T.

[0049] Next, a wafer processing procedure performed using the wafer processing system 1 configured as described above will be explained. In this embodiment, the first wafer W and the second wafer S are bonded together in a bonding device (not shown) outside the wafer processing system 1 to form a polymerized wafer T in advance. The following explanation will describe the case where the device layer Ds on the second wafer S side is transferred to the first wafer W side, but the same applies when the device layer Dw on the first wafer W side is transferred to the second wafer S side.

[0050] First, a hoop F containing multiple polymerized wafers T is placed on the hoop mounting platform 10 of the loading / unloading station 2 (St1 in Figure 5).

[0051] Next, the polymerized wafer T is transported to the laser irradiation device 50 by the wafer transport device 40. In the laser irradiation device 50, laser light is pulsed onto the laser absorption layer P (St2 in Figure 5). The laser light irradiated in St2 can be determined according to the material to be irradiated with the laser, such as the laser absorption layer P. In one embodiment, the laser light is CO ２ It is laser light, CO ２The wavelength of the laser light is, for example, 8.9 μm to 11 μm. In one embodiment, the laser light is an IR laser light, and the wavelength of the IR laser light is, for example, 1.5 μm to 2.5 μm. The laser light may be irradiated in a spiral pattern over the entire surface of the laser absorption layer P in a plan view, or it may be irradiated in a concentric ring pattern over the entire surface of the laser absorption layer P. Alternatively, the laser light may be irradiated onto the laser absorption layer P in a pulsed manner while moving a lens (not shown) included in the laser irradiation device in a linear direction. In this case, for example, a linear movement mechanism (transporter) may be provided for the lens to move it in a horizontal direction, or the laser light from the lens may be scanned by a galvanometer scanner (not shown), for example. The laser light passes through the second wafer S from the back surface Sb side of the second wafer S and is absorbed by the laser absorption layer P. This laser light reduces the bonding strength at the interface between the laser absorption layer P and the second wafer S. In this embodiment, "reduced bonding strength" means a state in which the bonding strength is reduced at least compared to before irradiation with laser light.

[0052] As described above, the polymerized wafer T that has undergone laser processing is then transported to the peeling device 60 by the wafer transport device 40. In the peeling device 60, the second wafer S is peeled from the first wafer W using the interface between the second wafer S, whose bonding strength has been reduced by laser irradiation, and the laser absorption layer P as the peeling surface (St3 in Figure 5).

[0053] The processing of the polymerized wafer in St3 will now be described. For the sake of clarity, the lifting mechanism 120, the moving mechanism 151, and the sensor 152 will not be shown in the following description and drawings. The polymerized wafer T, which has been transported to the peeling device 60, is first held by the adsorption of the back surface Wb of the first wafer W onto the holding surface 101a of the first holding part 101 (St101 in Figure 6).

[0054] Next, as shown in Figure 7(a), the blade 150 is inserted into the delamination surface at the interface between the first wafer W and the second wafer S, for example, between the laser absorption layer P and the surface Sa of the second wafer S, to form a delamination base point A (St102 in Figure 6). At St102, first, the blade 150 is inserted around the periphery of the delamination surface. Then, when the blade 150 is advanced further in the direction of the straight arrow in Figure 7(a), a delamination base point A is formed near the insertion position where the bonding between the first wafer W and the second wafer S is lost. Furthermore, with the blade 150 inserted, the first holding part 101 is moved to an angle θ in plan view, as shown by the curved arrow in Figure 7(a). １ Rotate it by only that much. Angle θ １ This can be, for example, 360 degrees or more. As a result, peeling points A are formed around the entire circumference of the polymerized wafer T in a plan view, as shown in Figure 8.

[0055] In one embodiment, St102 monitors the horizontal position or pressure of the blade 150 detected by the sensor 152 while the first holding part 101 is rotated with the blade 150 inserted. Based on the detected horizontal position or pressure of the blade 150, the horizontal position of the blade 150 is adjusted using the moving mechanism 151 so that a peeling base point A is formed on the peeling surface at a desired radial depth. This adjustment may be performed by feedback control of the moving mechanism 151 based on the detection results of the sensor 152 acquired in real time.

[0056] In one embodiment, by repeatedly inserting the blade 150 onto the periphery of the peeling surface, multiple peeling points A are formed at positions that are substantially rotationally symmetrical in a plan view of the polymerized wafer T. For example, the blade 150 is inserted onto the periphery of the peeling surface eight times each time the first holding part 101 is rotated by 45 degrees. As a result, as shown in Figure 9, eight peeling points A are formed at 45-degree intervals in a plan view of the polymerized wafer T. When multiple peeling points A are formed, the number and arrangement of the peeling points are not particularly limited, but may be determined in accordance with the number and arrangement of the outer adsorption parts 111e in the second holding part 102. In this embodiment as well, similarly to the above, the horizontal position of the blade 150 may be adjusted using the moving mechanism 151 so that peeling points A are formed on the peeling surface at a desired radial depth based on the detected horizontal position or pressure of the blade 150.

[0057] Next, as shown in Figure 7(b), the second holding portion 102 is lowered in the direction of the straight arrow, causing the back surface Sb of the second wafer S in the polymerized wafer T to be adsorbed and held by the adsorption portion 111 of the second holding portion 102 (St103 in Figure 6).

[0058] In one embodiment, as shown in Figure 10, when multiple peeling points A are formed on the polymerized wafer T by St102, the positions Sb on the back surface of the second wafer S corresponding to the formation positions of the peeling points A are adsorbed by the adsorption portion 111 of the second holding portion 102.

[0059] Next, with the back surface Sb of the second wafer S held by the second holding part 102, control is performed to rotate the first holding part 101 and the second holding part 102 relative to each other, as shown by the curved arrow in Figure 7(b) (S104 in Figure 6). In one embodiment, the motor 110 applies a stress σ1 to the first holding part 101 to rotate it. Since the first wafer W is held by the first holding part 101, the stress σ1 acts on the first wafer W. The stress σ1 is applied when the second wafer S detaches from the first wafer W and the first wafer W is not constrained by the second wafer S (i.e., by the second holding part 102), causing the first wafer W to move at an angle θ ２ The stress may be such that it is expected to rotate by only that much.２ The specific value is not particularly limited, and may be a desired minute angle.

[0060] While the stress σ1 that rotates the first holding portion 101 is applied by the motor 110, in the control device 61 or the control device 80, the rotation angle θ of the first holding portion 101 Ｍ is monitored (St105 in FIG. 6). The monitored rotation angle θ Ｍ reaches the threshold angle θ Ｔｈ , the process proceeds to St110 in FIG. 6. When the monitored rotation angle θ Ｍ does not reach the threshold angle θ Ｔｈ , the process proceeds to St120 in FIG. 6. Note that the threshold angle θ Ｔｈ may be a desired minute angle, or may be determined in advance based on the aforementioned angle θ ２ predetermined corresponding to the stress σ1. The monitoring of the rotation angle θ Ｍ may be performed within a predetermined time. In this case, when the monitored rotation angle θ Ｍ does not reach the threshold angle θ Ｔｈ within the predetermined time, the process proceeds to St120 in FIG. 6.

[0061] In one embodiment, the monitoring of the rotation angle θ of the first holding portion 101 in the control device 61 or the control device 80 Ｍ can be performed by a monitoring mechanism such as a camera (not shown). In another embodiment, the monitoring of the rotation angle θ of the first holding portion 101 in the control device 61 or the control device 80 Ｍ can be performed by monitoring the torque, rotation amount, and the like of the motor 110 via an encoder or a sensor (not shown) provided in the motor 110.

[0062] The rotation angle θ monitored in St105 Ｍ is the threshold angle θ ＴｈWhen this is reached, the second holding portion 102 is raised in the direction of the straight arrow, as shown in Figure 11, and the second wafer S is separated from the first wafer W (St110 in Figure 6). The method of raising the second holding portion 102 in St110 is not particularly limited. In one embodiment, the inner adsorption portion 111c and the outer adsorption portion 111e are raised simultaneously, causing the entire second wafer S to be raised simultaneously. In St110, the second holding portion 102 and the first holding portion 101 should be moved relative to each other so that they separate. For example, the first holding portion 101 may be lowered, or the second holding portion 102 may be raised while the first holding portion 101 is lowered. After the separation is completed in St110, the process proceeds to St4 in Figure 5.

[0063] Rotation angle θ monitored by St105 Ｍ The threshold angle θ Ｔｈ If this is not reached, the second holding portion 102 is then raised in steps in the radial direction, causing the second wafer S to be separated from the first wafer W (St120 in Figure 6). After the separation is completed at St120, the process proceeds to St4 in Figure 5.

[0064] The stepwise raising of the second holding portion 102 in St120 can be performed as follows. First, as shown in Figure 12(a), control is performed to raise the outer suction portion 111e in the direction of the straight arrow. This applies stress σ2 to the second wafer S. In one embodiment, if eight outer suction portions 111e are provided as shown in Figure 5, stress σ2 is applied equally to all eight outer suction portions 111e. In the example shown in Figure 12(a), the inner suction portion 111c is not raised and is held so that the central part of the second wafer S does not detach from the first wafer W. By performing control to raise the outer suction portion 111e, stress σ2 is applied to the peripheral edge of the second wafer S, and this peripheral edge first detaches from the first wafer W.

[0065] Next, as shown in Figure 12(b), control is performed to raise the inner adsorption portion 111c in the direction of the straight arrow. As a result, as shown in Figure 12(c), stress σ3 acts on the central part of the second wafer S, and the central part separates from the first wafer W. In other words, the second wafer S is separated from the first wafer W.

[0066] In one embodiment, if a plurality of inner adsorption portions 111c are provided, control may be performed to raise all of the plurality of inner adsorption portions 111c uniformly, thereby applying a uniform stress σ3 to the second wafer S.

[0067] In St120, peeling occurs gradually in the radial direction from the peeling point A, so that the stress acting on the first wafer W and the second wafer S is uniform in a direction of approximately rotational symmetry with respect to the center of either the first wafer W or the second wafer S. Therefore, separation can be achieved without placing an excessive load on the polymerized wafer T.

[0068] In St120 according to one embodiment, control may be performed to rotate the first holding portion 101 and the second holding portion 102 relative to each other, while simultaneously performing control to gradually raise the outer adsorption portion 111e and the inner adsorption portion 111c. This can be configured so that the stress σ4 that rotates the second wafer S and the first wafer W relative to each other acts on the first wafer W and the second wafer S, along with the stresses σ2 and σ3 that raise the second wafer S. In this case, the stresses σ2 and σ3 that raise the second holding portion 102 are distributed within the planes of the first wafer W and the second wafer S, and the stress acting on the first wafer W and the second wafer S becomes more uniform.

[0069] As described above, the first wafer W from which the second wafer S has been peeled off by the peeling device 60 is then transported to the cleaning device 70 by the wafer transport device 40. In the cleaning device 70, the surface Wa side of the first wafer W, which is the side peeled off from the second wafer S, specifically the surface of the laser absorption layer P, is cleaned (St4 in Figure 5). In addition, the back surface Wb of the first wafer W may also be cleaned in the cleaning device 70. Alternatively, separate cleaning units may be provided for cleaning the surface of the laser absorption layer P and the back surface Wb of the first wafer W, respectively.

[0070] Next, the first wafer W, which has been cleaned by the cleaning device 70, is removed from the cleaning device 70 by the wafer transfer device 40 and transported to the hoop F of the hoop mounting table 10 via the transition stage 30 and the wafer transfer device 20 (St5 in Figure 5).

[0071] Meanwhile, the second wafer S, which has been peeled off by the peeling device 60, is transported to the inversion device 31 by the wafer transport device 40. This transport of the second wafer S by the wafer transport device 40 may be performed simultaneously with the transport of the first wafer W, or it may be performed independently. In the inversion device 31, the front and back surfaces of the second wafer S are inverted so that the front surface Sa faces upward (St6 in Figure 5).

[0072] Next, the second wafer S, with its surface Sa facing upwards, is transported to the cleaning device 70 by the wafer transport device 40. In the cleaning device 70, the surface Sa of the second wafer S, which is the side that was peeled off from the first wafer W, is cleaned (St7 in Figure 5). In addition, the back surface Sb of the second wafer S may also be cleaned in the cleaning device 70. Alternatively, separate cleaning units may be provided for cleaning the surface Sa and the back surface Sb, respectively.

[0073] Next, the second wafer S, which has been cleaned by the cleaning device 70, is removed from the cleaning device 70 by the wafer transfer device 40 and transported to the hoop F of the hoop mounting table 10 via the transition stage 30 and the wafer transfer device 20 (St8 in Figure 5).

[0074] Subsequently, once processing is complete on all the polymerized wafers T housed in the hoop F, the series of wafer processing operations in the wafer processing system 1 is finished.

[0075] An example of the significance of each component of the peeling apparatus 60 and peeling process St3 configured as described above will be explained. In conventional peeling methods, for example, as described in Patent Document 1, stress is applied vertically to one edge of one wafer, and peeling is carried out from that edge to the other edge.

[0076] In contrast, in the peeling process of St3 according to this embodiment, stresses σ1 to σ4 that cause relative displacement of the first holding portion 101 and the second holding portion 102 act on the first wafer W or the second wafer S. These stresses σ1 to σ4 all act in a direction that is substantially rotationally symmetric with respect to the center of the first wafer W or the second wafer S. Therefore, it is possible to suppress localized stress concentration on the first wafer W and the second wafer S, and to suppress damage to the first wafer W and the second wafer S. Note that "relative displacement" includes separation due to relative rotation or movement of the first holding portion 101 and the second holding portion 102 as described above, or separation due to deformation as described later.

[0077] Furthermore, a stress σ1 is applied at St104, and the actual rotation angle θ of the first holding part 101 is determined at St105. Ｍ By monitoring this, the degree of decrease in bonding strength between the first wafer W and the second wafer S can be estimated.

[0078] The rotation angle θ is being monitored. Ｍ The threshold angle θ Ｔｈ If the wafer is rotated by only a certain amount, it can be determined that the degree of reduction in bonding strength between the first wafer W and the second wafer S is high. The degree of reduction in bonding strength refers to how easily the first wafer W and the second wafer S can be separated by a process that includes irradiation with laser light at St2 and formation of a delamination point A at St102.

[0079] If it is determined that the degree of reduction in bonding strength between the first wafer W and the second wafer S is high, it is understood that there is a low possibility of damage to the first wafer W and the second wafer S during delamination. Therefore, in St110, the inner adsorption part 111c and the outer adsorption part 111e are raised simultaneously, and the entire second wafer S is raised at the same time, thereby shortening the time required for delamination.

[0080] On the other hand, the rotation angle θ monitored by St105 Ｍ The threshold angle θ ＴｈIf the bond strength does not reach this level, it can be determined that the degree of reduction in bonding strength between the first wafer W and the second wafer S is low. Based on this determination, processing can be performed thereafter according to the degree of reduction in bonding strength between the first wafer W and the second wafer S, thereby enabling proper delamination.

[0081] Therefore, in St120, delamination is performed such that the stresses σ2 to σ4 acting on the first wafer W and the second wafer S are uniform in a substantially rotationally symmetric direction with respect to the center of either the first wafer W or the second wafer S. This suppresses localized concentration of stress acting on the first wafer W and the second wafer S. Consequently, even if the degree of reduction in bonding strength between the first wafer W and the second wafer S is low, it is expected that the possibility of damage to the first wafer W and the second wafer S will be reduced.

[0082] Furthermore, prior to applying stress σ2 to the outer adsorption portion 111e of the second holding portion 102 in St120, peeling base points A are formed in St102 at positions that are approximately rotationally symmetrical in the plan view of the polymerized wafer T (including the entire circumference). This suppresses stress imbalance in St120 due to the presence or absence or unevenness of peeling base points A.

[0083] In one embodiment, the rotation angle θ monitored by St105 Ｍ The threshold angle θ Ｔｈ If this is not achieved, the process may return to St102 and repeat the formation of the peeling base point A. This is expected to reduce the likelihood of damage to the first wafer W and the second wafer S during the subsequent peeling of St110 or St120.

[0084] In one embodiment, the peeling process of St3 may be configured to perform St120 after St103, without performing St104, St105, and St110. That is, after forming the peeling base point A with St102 and holding the second wafer S in the second holding part 102, the second holding part 102 may be raised in steps immediately with St120. In this case, damage to the first wafer W and the second wafer S by St120 can be suppressed regardless of the degree of reduction in bonding force between the first wafer W and the second wafer S.

[0085] In one embodiment, the execution order of St102 and St103 in the peeling process of St3 may be reversed.

[0086] In one embodiment, the formation of the peeling base point A of St102 may be omitted after St101, and the process from St103 onwards may be executed. In one embodiment, the formation of the peeling base point A of St102 may be omitted before executing St104 and St105, and the rotation angle θ monitored at St105 may be used. Ｍ The threshold angle θ Ｔｈ Only if this condition is not reached may the formation of the peeling base point A of St102 be performed.

[0087] The peeling apparatus 60 according to the above embodiment has an inner adsorption portion 111c and an outer adsorption portion 111e arranged symmetrically with respect to the center 102c in the second holding portion 102, and these can be raised in stages so that the peeling stress becomes uniform across the wafer surface. With respect to the first holding portion 101 and the second holding portion 102, the following modifications can be considered from the viewpoint of configuring them so that the stress acting on the first wafer W and the second wafer S is uniform in a symmetrical direction with respect to the center of the first wafer W or the second wafer S.

[0088] As shown in Figure 13, the modified peeling device 60 comprises a first holding portion 201 and a second holding portion 202.

[0089] The first holding portion 201 includes a holding surface 201a that contacts the back surface Wb of the first wafer W in the polymerized wafer T and holds the first wafer W. In the example state shown in Figure 13, the back surface Wb of the first wafer W in the polymerized wafer T is held by the holding surface 201a of the first holding portion 201. The means of holding in the first holding portion 201 is not particularly limited, and electrostatic adsorption or vacuum adsorption can be used.

[0090] The second holding portion 202 has a holding surface 202a that holds the first wafer W in contact with the back surface Sb of the second wafer S in the polymerized wafer T. The second holding portion 202 has the same configuration as the first holding portion 201.

[0091] The first holding portion 201 is configured to be able to deform the holding surface 201a to a desired position in the out-of-plane direction. Similarly, the second holding portion 202 is configured to be able to deform the holding surface 202a to a desired position in the out-of-plane direction.

[0092] The means for deforming the holding surface 201a of the first holding portion 201 and the holding surface 202a of the second holding portion 202 are not particularly limited.

[0093] In the example shown in Figure 14, a blade 150 is inserted into one end of the polymerized wafer T, forming a peeling point A. In this example, the end 201e of the first holding part 201, which holds the first wafer W at the end of the polymerized wafer T where the peeling point A is formed, is deformed downward. As a result, the first wafer W held by the first holding part 201 is similarly deformed downward. Also, the end 202e of the second holding part 202, which holds the second wafer S at the end of the polymerized wafer T where the peeling point A is formed, is deformed upward. As a result, the second wafer S held by the second holding part 202 is similarly deformed upward. Then, due to the deformation of the first holding part 201 and the second holding part 202, the peeling of the first wafer W and the second wafer S proceeds with the peeling point A as the starting point. Subsequently, the first holding part 201 and the second holding part 202 are moved to separate relatively, causing the second wafer S to be peeled from the first wafer W.

[0094] In the example shown in Figure 15, the blade 150 is inserted around the entire circumference of the polymerized wafer T, forming a delamination point A. In this example, the end portion 201e of the first holding portion 201 is deformed downwards around its entire circumference. As a result, the first wafer W held by the first holding portion 201 is similarly deformed downwards around its entire circumference. Similarly, the end portion 202e of the second holding portion 202 is deformed downwards around its entire circumference. As a result, the second wafer S held by the second holding portion 202 is similarly deformed upwards around its entire circumference. Due to the deformation of the first holding portion 201 and the second holding portion 202, delamination of the first wafer W and the second wafer S progresses with the delamination point A as the starting point. At this time, the stress acting on the first wafer W and the second wafer S is considered to act in a direction of approximately rotational symmetry with respect to the center of either the first wafer W or the second wafer S.

[0095] In the peeling process of St3 according to one embodiment using the peeling device 60 according to the modified example, at St120, as shown in Figure 15, at least one of the first holding portion 201 and the second holding portion 202 may be deformed so that peeling progresses around the entire circumference of the polymerized wafer T. In one embodiment, St102 may not be performed, that is, without forming a peeling base point A, and at least one of the first holding portion 201 and the second holding portion 202 may be deformed.

[0096] In one embodiment, the modified first retaining portion 201 may be combined with the second retaining portion 102 according to the above embodiment. Also, the modified second retaining portion 202 may be combined with the first retaining portion 101 according to the above embodiment.

[0097] In the embodiments described above, a laser light was irradiated onto a laser absorption layer P formed between a first wafer W and a second wafer S, and the second wafer S was peeled off using the interface between the laser absorption layer P and the second wafer S as the peeling surface. However, the wafer processing to which the technology of this disclosure is applied is not limited thereto.

[0098] For example, instead of delaminating the second wafer S at the interface between the second wafer S and the laser absorption layer P, the technology of this disclosure can be applied when delaminating the second wafer S using the interface between the laser absorption layer P and the device layer Ds, the interface between the bonding layer Fs and the bonding layer Fw, the inner surface of the bonding layer Fs or bonding layer Fw, or the inner surface of a desired temporary bonding layer or the interface between the temporary bonding layer and other layers as the delamination surface. Furthermore, for example, the technology of this disclosure can be applied when delaminating the second wafer S from the first wafer W by fracturing the laser absorption layer P. The technology of this disclosure can also be applied when forming the delamination surface by means other than irradiating the laser absorption layer P with laser light.

[0099] For example, the laminated film on the surface Sa of the second wafer S may include a delamination-promoting layer (not shown) formed between the laser absorption layer P and the second wafer S, and the second wafer S may be delaminated from the first wafer W using the interface between the delamination-promoting layer and the laser absorption layer P as the delamination surface. In this case, it is desirable that the delamination-promoting layer is one in which the adhesion force between the delamination-promoting layer and the laser absorption layer P is at least smaller than the adhesion force between the second wafer S and the delamination-promoting layer. Furthermore, for example, the laminated film on the surface Sa of the second wafer S may include a protective film for the surface Sa formed between the laser absorption layer P and the second wafer S, and the second wafer S may be delaminated from the first wafer W using the interface between the protective film and the laser absorption layer P as the delamination surface. Also, for example, the device layer Ds may include a laser light reflective film or a delamination-promoting film, and if a delamination-promoting layer is included, the second wafer S may be delaminated from the first wafer W using the interface between the delamination-promoting layer and the laser absorption layer P as the delamination surface.

[0100] Furthermore, the technology of this disclosure can also be applied, for example, when a modified surface is formed by irradiating the interior of the second wafer S with laser light along the planar direction, and the second wafer S is thinned by peeling off the back surface Sb side using the modified surface as a starting point.

[0101] The embodiments disclosed herein should be considered in all respects as illustrative and not restrictive. The embodiments described above may be omitted, replaced, or modified in various ways without departing from the scope and spirit of the appended claims. For example, the constituent elements of the embodiments described above can be combined in any way. Such any combination will naturally yield the functions and effects of each constituent element in the combination, as well as other functions and effects that will be apparent to those skilled in the art from the description herein.

[0102] Furthermore, the effects described herein are merely descriptive or illustrative and not limiting. In other words, the technology relating to this disclosure may produce other effects that are obvious to those skilled in the art from the description herein, in addition to or instead of the effects described herein.

[0103] 60 Peeling device 61 Control device 80 Control device 101 First holding unit 102 Second holding unit 110 Motor 120 Lifting mechanism S Second wafer T Polymerized wafer W First wafer σ1 Stress σ2 Stress σ3 Stress σ4 Stress

Claims

1. A substrate processing method for processing a polymerized substrate in which a first substrate and a second substrate are joined, comprising: holding the first substrate by adsorption with a first holding portion; holding the second substrate by adsorption with a second holding portion; and applying a stress to the first substrate and the second substrate in a direction substantially rotationally symmetric with respect to the centers of the first substrate and the second substrate by relatively displacing the first holding portion and the second holding portion.

2. A substrate processing method according to claim 1, comprising: applying a first rotational stress as the stress to the first substrate and the second substrate in order to displace the first and second holding portions relative to each other; and monitoring the relative rotation angle of the first and second holding portions while the first stress is being applied.

3. The substrate processing method according to claim 2, wherein when the monitored rotation angle reaches a predetermined threshold angle, the first holding portion and the second holding portion are displaced relative to each other, the method comprising separating the first holding portion and the second holding portion relative to each other.

4. The substrate processing method according to claim 2, wherein the second holding portion comprises a plurality of suction portions provided substantially rotationally symmetrically with respect to the center of the second holding portion in a plan view, the suction portions include at least one inner suction portion provided radially inward of the second holding portion and three or more outer suction portions provided radially outward, and when the monitored rotation angle does not reach a predetermined threshold angle, the method displaces the first holding portion and the second holding portion relatively, and the method includes applying the following stresses to the second substrate in this order: a second stress that raises the outer suction portions and a third stress that raises the inner suction portions.

5. The substrate processing method according to claim 1, wherein the second holding portion comprises a plurality of suction portions provided substantially rotationally symmetrically with respect to the center of the second holding portion in a plan view, the suction portions include at least one inner suction portion provided radially inward of the second holding portion and three or more outer suction portions provided radially outward, and the method for processing a substrate according to claim 1, wherein the stresses are applied to the second substrate in the order of: a second stress that raises the outer suction portions and a third stress that raises the inner suction portions, in order to displace the first holding portion and the second holding portion.

6. The substrate processing method according to claim 1, wherein the first holding portion has a first holding surface for adsorbing and holding the first substrate, and is configured to be deformable in the out-of-plane direction, and the substrate processing method includes, in displacing the first holding portion and the second holding portion relative to each other, applying a fifth stress, which is the stress, to the first substrate, causing the entire circumference of the peripheral edge of the first substrate to deform in the out-of-plane direction.

7. The substrate processing method according to claim 1, wherein the second holding portion has a second holding surface for adsorbing and holding the second substrate, and is configured to be deformable in the out-of-plane direction, and the substrate processing method includes, in displacing the first holding portion and the second holding portion relative to each other, applying a sixth stress to the second substrate, which is the stress, to deform the entire circumference of the peripheral edge of the first substrate in the out-of-plane direction.

8. A substrate processing method according to any one of claims 1 to 7, comprising forming a peeling point at a substantially rotationally symmetric position in a plan view of the bonding interface between the first substrate and the second substrate before relatively displacing the first holding portion and the second holding portion.

9. The substrate processing method according to claim 8, wherein the peeling base point is formed around the entire circumference of the bonding interface.

10. A substrate processing apparatus for processing a polymerized substrate in which a first substrate and a second substrate are joined, comprising: a first holding part for adsorbing and holding the first substrate; a second holding part for adsorbing and holding the second substrate; a displacement mechanism for displacing the first holding part and the second holding part relative to at least one of the first substrate and the second substrate; and a control unit, wherein the control unit controls the displacement mechanism to displace the first holding part and the second holding part relative to each other, thereby performing control that applies a stress to the first substrate and the second substrate in a direction substantially rotationally symmetric with respect to the centers of the first substrate and the second substrate.

11. The substrate processing apparatus according to claim 10, wherein at least one of the first holding portion and the second holding portion is provided with a rotation mechanism for relatively rotating the first holding portion and the second holding portion as a displacement mechanism, and the control unit performs control including controlling the rotation mechanism to apply a first rotational stress as the stress to the first substrate and the second substrate, and monitoring the relative rotation angle of the first holding portion and the second holding portion while the first stress is being applied.

12. The substrate processing apparatus according to claim 11, wherein the control unit, when the monitored rotation angle reaches a predetermined threshold angle, performs control that includes relatively separating the first holding portion and the second holding portion in order to displace them relative to each other.

13. The substrate processing apparatus according to claim 11, wherein the second holding portion comprises a plurality of suction portions provided substantially rotationally symmetrically with respect to the center of the second holding portion in a plan view, and a lifting mechanism as the displacement mechanism configured to move the suction portions, the suction portions include at least one inner suction portion provided radially inward of the second holding portion and three or more outer suction portions provided radially outward, and the control unit, when the monitored rotation angle does not reach a predetermined threshold angle, performs control including applying the following stresses to the second substrate in this order: a second stress to raise the outer suction portions and a third stress to raise the inner suction portions.

14. The substrate processing apparatus according to claim 10, wherein the second holding portion comprises a plurality of suction portions provided substantially rotationally symmetrically with respect to the center of the second holding portion in a plan view, and a lifting mechanism as the displacement mechanism configured to move the suction portions, the suction portions include at least one inner suction portion provided radially inward of the second holding portion, and three or more outer suction portions provided radially outward, and the control unit performs control that, in displacing the first holding portion and the second holding portion relative to each other, applies the following stresses to the second substrate in this order: a second stress that raises the outer suction portions, and a third stress that raises the inner suction portions.

15. The substrate processing apparatus according to claim 10, wherein the first holding portion has a first holding surface for adsorbing and holding the first substrate, and comprises a deformation mechanism as the displacement mechanism configured to deform the first holding surface in the out-of-plane direction, and the control unit controls the deformation mechanism to displace the first holding portion and the second holding portion relative to each other, and performs control including applying a fifth stress as the stress to the first substrate, which deforms the entire circumference of the peripheral edge of the first substrate in the out-of-plane direction.

16. The substrate processing apparatus according to claim 10, wherein the second holding portion has a second holding surface for adsorbing and holding the second substrate, and comprises a deformation mechanism as the displacement mechanism configured to deform the second holding surface in the out-of-plane direction, and the control unit controls the deformation mechanism to displace the first holding portion and the second holding portion relative to each other, and performs control including applying a sixth stress as the stress to the second substrate, which deforms the entire circumference of the peripheral edge of the first substrate in the out-of-plane direction.

17. A substrate processing apparatus according to any one of claims 10 to 16, comprising a base point forming unit, wherein the control unit controls the base point forming unit to form a peeling base point at a substantially rotationally symmetric position in a plan view of the bonding interface between the first substrate and the second substrate, before displacing the first holding unit and the second holding unit relative to each other.

18. The substrate processing apparatus according to claim 17, wherein the control unit controls the base point forming unit to perform control including forming the peeling base point around the entire circumference of the bonding interface.

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