Processing method and processing system

Abstract

This processing method is for a combined substrate obtained by bonding a first substrate and a second substrate together, the method including: irradiating the interface between the first substrate and the second substrate with an interface laser light to form an unbonded region that has a reduced bonding strength at the interface; inspecting the state of formation of the unbonded region; forming a peripheral modified layer along the boundary between a peripheral part of the first substrate and a middle part of the first substrate; and removing the peripheral part by using the peripheral modified layer as an origin. Inspecting the state of formation of the unbonded region includes: using a camera to image the unbonded region; acquiring a distribution of gray values in plan view of the unbonded region from a captured image of the unbonded region; and comparing the acquired gray values against a preset threshold value, to thereby inspect the state of formation of the unbonded region.

Description

[Technical Field]

[0001] The present disclosure relates to a processing method and a processing system. [Background technology]

[0002] Patent document 1 discloses a substrate processing system having a modified layer forming device that forms a modified layer inside a first substrate to be removed along the boundary between the peripheral and central portions of the first substrate in a laminated substrate formed by bonding a first substrate and a second substrate, and an edge removal device that removes the peripheral portion of the first substrate using the modified layer as a base point. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2019 / 176589 Summary of the Invention [Problem to be solved by the invention]

[0004] The technique according to the present disclosure appropriately removes the peripheral edge portion of the first substrate in a laminated substrate in which a first substrate and a second substrate are bonded together. [Means for solving the problem]

[0005] One aspect of the present disclosure is a method for processing a laminated substrate in which a first substrate and a second substrate are bonded together, the method including: irradiating an interface between the first substrate and the second substrate with an interface laser light to form an unbonded region at the interface where bonding strength is reduced; inspecting the formation state of the unbonded region; forming a peripheral modified layer along a boundary between a peripheral portion of the first substrate and a central portion of the first substrate; and removing the peripheral portion using the peripheral modified layer as a base point; the inspection of the formation state of the unbonded region includes imaging the unbonded region using a camera; and calculating a distribution of gray values ​​in a planar view of the unbonded region from the image of the unbonded region. For each of a plurality of divided regions arranged in at least one of the circumferential direction and the radial direction of the first substrate,and comparing the acquired gray value with a preset threshold value to inspect the formation state of the unbonded region. [Effects of the Invention]

[0006] According to the present disclosure, in a laminated substrate in which a first substrate and a second substrate are bonded together, the peripheral edge portion of the first substrate can be appropriately removed. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 2 is a side view showing an example of the configuration of an overlapping wafer to be processed. [Figure 2] 1 is a plan view showing an outline of the configuration of a wafer processing system according to an embodiment of the present invention. [Figure 3] 1 is a cross-sectional view showing an unbonded region, a peripheral modified layer, and a divided modified layer formed on a laminated wafer. [Figure 4] FIG. 2 is a plan view showing the outline of the configuration of an interface reforming device and an internal reforming device. [Figure 5] FIG. 2 is a side view showing the outline of the configuration of an interface reformer and an internal reformer. [Figure 6] 1 is an explanatory diagram showing main steps of wafer processing in a wafer processing system. [Figure 7] FIG. 2 is a flow chart showing the main steps of wafer processing in the wafer processing system. [Figure 8] FIG. 2 is an explanatory diagram showing the main steps of an inspection in the interface modification device. [Figure 9] FIG. 2 is an explanatory diagram showing the main steps of an inspection in the interface modification device. [Figure 10] FIG. 1 is a flow chart showing the main steps of an inspection in an interface modification device. [Figure 11] FIG. 10 is an explanatory diagram showing an inspection state in the internal reformer. [Figure 12] FIG. 10 is an explanatory diagram showing an inspection state in the internal reformer. [Figure 13] FIG. 10 is an explanatory diagram showing an inspection state in the internal reformer. [Figure 14] FIG. 10 is an explanatory diagram showing an inspection state in the internal reformer. [Figure 15] FIG. 10 is an explanatory diagram showing an inspection state in the internal reformer. [Figure 16] FIG. 2 is a flow chart showing the main steps of an inspection in an internal reformer. [Figure 17] 10A and 10B are explanatory views showing another example of forming a peripheral modified layer inside the first wafer. [Figure 18] FIG. 10 is an explanatory diagram showing an inspection process in the edge removing device. [Figure 19] FIG. 10 is an explanatory diagram showing an inspection process in the edge removing device. [Figure 20] FIG. 10 is an explanatory diagram showing an inspection process in the edge removing device. [Figure 21] FIG. 10 is an explanatory diagram showing an inspection process in the edge removing device. [Figure 22] FIG. 10 is an explanatory diagram showing an inspection process in the edge removing device. [Figure 23] FIG. 1 is a flow chart showing main steps of inspection in the edge removing device. DETAILED DESCRIPTION OF THE INVENTION

[0008] In the manufacturing process of semiconductor devices, a first substrate (a silicon substrate such as a semiconductor) on the surface of which a plurality of devices such as electronic circuits are formed is bonded to a second substrate, and the first substrate In some cases, the peripheral portion of the substrate is removed, which is called edge trimming.

[0009] The edge trimming of the first substrate is performed using, for example, the substrate processing system disclosed in Patent Document 1. That is, a modified layer is formed by irradiating the inside of the first substrate with laser light, and the peripheral portion of the first substrate is removed using the modified layer as a base point. Furthermore, according to the substrate processing system described in Patent Document 1, a modified surface is formed by irradiating the interface where the first substrate and the second substrate are bonded with laser light, thereby reducing the bonding strength between the first substrate and the second substrate at the peripheral portion and appropriately removing the peripheral portion.

[0010] However, when forming a modified surface to reduce the bonding strength at the interface where the first substrate and the second substrate are bonded, there is a risk that the modified surface may not be properly formed on the entire peripheral portion of the substrate to be removed due to various factors, such as misalignment of the axis of the laser beam. If the modified surface cannot be formed on the entire peripheral portion, for example, if the modified surface is not formed in a portion of the circumferential direction or if the width of the modified surface formed is not uniform over the entire periphery, a portion of the peripheral portion of the first substrate to be removed may remain near the center of the first substrate, which may cause particles to be generated in subsequent processes.

[0011] The technology disclosed herein has been made in consideration of the above circumstances, and in a laminated substrate in which a first substrate and a second substrate are bonded, the peripheral portion of the first substrate is appropriately removed. Hereinafter, a wafer processing system as a processing system and a wafer processing method as a processing method according to this embodiment will be described with reference to the drawings. Note that in this specification and the drawings, elements having substantially the same functional configuration are designated by the same reference numerals, and redundant description will be omitted.

[0012] In a wafer processing system 1 according to this embodiment, which will be described later, processing is performed on a laminated wafer T, which is a laminated substrate formed by bonding a first wafer W as a first substrate and a second wafer S as a second substrate, as shown in Fig. 1. Hereinafter, the surface of the first wafer W that is bonded to the second wafer S will be referred to as the front surface Wa, and the surface opposite the front surface Wa will be referred to as the back surface Wb. Similarly, the surface of the second wafer S that is bonded to the first wafer W will be referred to as the front surface Sa, and the surface opposite the front surface Sa will be referred to as the back surface Sb.

[0013] The first wafer W is a semiconductor wafer such as a silicon substrate, and has a device layer Dw including a plurality of devices formed on its surface Wa. A bonding film Fw is further formed on the device layer Dw, and the first wafer W is bonded to the second wafer S via the bonding film Fw. The bonding film Fw may be, for example, an oxide film (THOX film, SiO2 film, TEOS film), a SiC film, a SiCN film, or an adhesive. The peripheral edge We of the first wafer W is chamfered, and the cross section of the peripheral edge We becomes thinner toward its tip. The peripheral edge We is a portion to be removed in the edge trimming process described below, and is, for example, a region radially inward from the outer edge of the first wafer W, extending 0.5 mm to 3 mm. In the following description, the region of the first wafer W radially inward of the peripheral edge We to be removed may be referred to as the central region We.

[0014] The second wafer S has, for example, the same configuration as the first wafer W, and has a device layer Ds and a bonding film Fs formed on its surface Sa, and its peripheral edge is chamfered. Note that the second wafer S does not necessarily have to be a device wafer on which the device layer Ds is formed, and may be, for example, a support wafer that supports the first wafer W. In such a case, the second wafer S functions as a protective material that protects the device layer Dw of the first wafer W.

[0015] 2, wafer processing system 1 has a configuration in which a load / unload station 2 and a processing station 3 are integrally connected. In load / unload station 2, for example, a cassette C capable of accommodating a plurality of overlapped wafers T is loaded and unloaded between the load / unload station 2 and the outside. Processing station 3 is equipped with various processing devices that perform desired processing on overlapped wafers T.

[0016] The loading / unloading station 2 is provided with a cassette mounting table 10 on which a cassette C capable of accommodating a plurality of overlapped wafers T is mounted. A wafer transfer device 20 is provided adjacent to the cassette mounting table 10 on the positive side of the X-axis of the cassette mounting table 10. The wafer transfer device 20 moves on a transfer path 21 extending in the Y-axis direction, and is configured to be able to transfer the overlapped wafers T between the cassette C on the cassette mounting table 10 and a transition device 30, which will be described later.

[0017] In the loading / unloading station 2, a transition device 30 for transferring the overlapped wafer T to and from the processing station 3 is provided adjacent to the wafer transfer device 20 on the positive side of the X axis of the wafer transfer device 20.

[0018] In the processing station 3, a wafer transfer device 40, an interface modification device 50, an internal modification device 60, a peripheral removal device 70, and a cleaning device 80 are arranged.

[0019] The wafer transfer device 40 is provided on the positive X-axis side of the transition device 30. The wafer transfer device 40 is configured to be movable on a transfer path 41 extending in the X-axis direction, and is configured to be able to transfer the overlapped wafer T to the transition device 30, interface modification device 50, internal modification device 60, edge removal device 70, and cleaning device 80 of the carry-in / out station 2.

[0020] The interface modification device 50 irradiates the interface between the first wafer W and the second wafer S with laser light (interface laser light, for example, a CO2 laser), and forms an unbonded area Ae (see Figure 3) in the peripheral portion We to be removed, where the bonding strength between the first wafer W and the second wafer S is reduced.

[0021] As shown in FIGS. 4 and 5 , the interface modification apparatus 50 includes a chuck 100 that holds the overlapped wafer T on its upper surface. The chuck 100 holds the back surface Sb of the second wafer S by suction, with the first wafer W on top and the second wafer S on the bottom. The chuck 100 is supported by a slider table 102 via an air bearing 101. A rotation mechanism 103 is provided on the underside of the slider table 102. The rotation mechanism 103 incorporates, for example, a motor as a drive source. The chuck 100 is configured to be rotatable about a vertical axis by the rotation mechanism 103 via the air bearing 101. The slider table 102 is configured to be movable on a rail 106 extending in the Y-axis direction on a base 105 via a movement mechanism 104 provided on the underside of the slider table 102. The drive source of the movement mechanism 104 is not particularly limited, but may be, for example, a linear motor.

[0022] A laser head 110 is provided above the chuck 100. The laser head 110 has a lens 111. The lens 111 is a cylindrical member provided on the underside of the laser head 110, and irradiates the interior of the overlapped wafer T held by the chuck 100, more specifically, the interface between the first wafer W and the second wafer S, with an interface laser beam. This modifies the portion of the overlapped wafer T irradiated with the interface laser beam, forming an unbonded region Ae in which the bonding strength between the first wafer W and the second wafer S is reduced. Note that, in the technology disclosed herein, the "interface between the first wafer W and the second wafer S" includes the respective interfaces and interiors of the first wafer W, device layers Dw, Ds, bonding films Fw, Fs, and second wafer S. In other words, the position where the unbonded region Ae is formed is not particularly limited as long as the bonding strength between the first wafer W and the second wafer S can be reduced.

[0023] The laser head 110 is supported by a support member 112. The laser head 110 is configured to be able to move up and down by an elevating mechanism 114 along rails 113 extending in the vertical direction. The laser head 110 is also configured to be able to move in the Y-axis direction by a moving mechanism 115. The elevating mechanism 114 and the moving mechanism 115 are each supported by a support column 116.

[0024] A macro camera 120 and a micro camera 121 are provided above the chuck 100, on the Y-axis positive side of the laser head 110. For example, the macro camera 120 and the micro camera 121 are configured as an integrated unit, with the macro camera 120 being disposed on the Y-axis positive side of the micro camera 121. The macro camera 120 and the micro camera 121 are configured to be able to move up and down freely by an elevating mechanism 122, and are further configured to be able to move freely in the Y-axis direction by a moving mechanism 123. The moving mechanism 123 is supported by a support column 116.

[0025] The macro camera 120 captures an image of the outer edge of the first wafer W (polymerized wafer T). The image captured by the macro camera 120 is used, for example, for alignment of the first wafer W, which will be described later. The macro camera 120 includes, for example, a coaxial lens, and irradiates light that is at least transparent to the first wafer W, for example, infrared light (IR), and further receives reflected light from an object. Note that the imaging magnification of the macro camera 120 is, for example, 2x.

[0026] The micro camera 121 captures an image of the unbonded region Ae formed at the interface between the first wafer W and the second wafer S. The image captured by the micro camera 121 is used, for example, to detect whether the unbonded region Ae has been properly formed. The micro camera 121 includes, for example, a coaxial lens, and irradiates light that is transparent to at least the first wafer W, such as infrared light (IR light), and further receives reflected light from an object. For example, the imaging magnification of the micro camera 121 is 10 times, the field of view is approximately 1 / 5 of that of the macro camera 120, and the pixel size is approximately 1 / 5 of that of the macro camera 120.

[0027] In this embodiment, a macro camera 120 and a micro camera 121 are arranged as shown in the figure, and an image of the unbonded area Ae formed at the interface between the first wafer W and the second wafer S is captured. By capturing an image of the unbonded area Ae using the micro camera 121 with such a high imaging magnification, the unbonded area Ae can be detected with higher accuracy than when capturing an image of the unbonded area Ae using the macro camera 120.

[0028] In this embodiment, the macro camera 120 and the micro camera 121 are arranged as shown in the figure, but the macro camera 120 may be omitted if, for example, the outer edge of the first wafer W can be properly imaged using the micro camera 121.

[0029] In the illustrated example, the chuck 100 is configured to be rotatable relative to the laser head 110 and movable in the horizontal direction by the rotation mechanism 103 and the movement mechanism 104, but the laser head 110 may be configured to be rotatable relative to the chuck 100 and movable in the horizontal direction. Also, both the chuck 100 and the laser head 110 may be configured to be rotatable relative to each other and movable in the horizontal direction.

[0030] The internal modification device 60 irradiates the inside of the first wafer W with laser light (internal laser light, e.g., YAG laser) to form a peripheral modified layer M1 that serves as the base point for peeling off the peripheral portion We and a divided modified layer M2 (see Figure 3) that serves as the base point for breaking the peripheral portion We into small pieces.

[0031] The configuration of the internal reforming device 60 is not particularly limited. In one example, the internal reforming device 60 has a configuration similar to that of the interface reforming device 50. That is, as shown in FIG. 4, the internal reforming device 60 includes a chuck 200 that holds the overlapped wafer T on its upper surface, a laser head 210 that irradiates the inside of the first wafer W held on the chuck 200 with an internal laser beam, and a macro camera 220 and a micro camera 221 that capture images of the overlapped wafer T held on the chuck 200. The laser head 210 includes a lens 211. The laser head 210 is configured to be freely movable by a support member 212, a rail 213, an elevating mechanism 214, and a moving mechanism 215. The elevating mechanism 214 and the moving mechanism 215 are each supported by a support column 216. The macro camera 220 and the micro camera 221 are configured to be freely movable by an elevator mechanism 222 and a moving mechanism 223. The moving mechanism 223 is supported by a support column 216.

[0032] The chuck 200 and the laser head 210 are configured to be relatively rotatable and horizontally movable by, for example, a rotation mechanism 203 and a movement mechanism 204. The laser head 210 has a lens 211 for irradiating the inside of the first wafer W held by the chuck 200 with internal laser light.

[0033] The macro camera 220 captures an image of the outer edge of the first wafer W (the overlapped wafer T). The image captured by the macro camera 220 is used, for example, for alignment of the first wafer W, which will be described later. The micro camera 221 captures an image of the vicinity of the peripheral portion We of the first wafer W, more specifically, an area including from the outer edge of the first wafer W to a position slightly radially inward from the planned formation position of the peripheral modified layer M1 (the outer edge of the central portion Wc of the first wafer W that remains on the overlapped wafer T due to the edge trimming). The image captured by the micro camera 221 is used, for example, to detect whether the peripheral modified layer M1 has been properly formed inside the first wafer W.

[0034] The edge removal device 70 removes the edge portion We of the first wafer W, i.e., performs edge trimming, using the edge modified layer M1 formed in the internal modification device 60 as a base point. Any method for edge trimming can be selected. In one example, the edge removal device 70 may insert, for example, a wedge-shaped blade. Alternatively, for example, an impact may be applied to the edge portion We by spraying air or a water jet toward the edge portion We.

[0035] Furthermore, the peripheral edge removing device 70 may use an imaging mechanism 71 (see FIG. 20) to capture an image of the peripheral edge of the overlapped wafer T after the peripheral edge We has been removed, and detect whether the peripheral edge We has been properly removed from the first wafer W. In this case, a CCD camera, for example, may be used as the imaging mechanism 71.

[0036] The cleaning device 80 performs a cleaning process on the first wafer W and the second wafer S after the edge trimming in the edge removal device 70, thereby removing particles from these wafers. Any cleaning method can be selected.

[0037] The wafer processing system 1 described above is provided with a control device 90. The control device 90 is, for example, a computer, and has a program storage unit (not shown). The program storage unit stores a program for controlling the processing of the overlapped wafer T in the wafer processing system 1. The program storage unit also stores a program for controlling the operation of drive systems such as the various processing devices and transport devices described above to realize wafer processing, which will be described later, in the wafer processing system 1. The program may be recorded on a computer-readable storage medium H and installed from the storage medium H into the control device 90. The storage medium H may be temporary or non-temporary.

[0038] Next, a description will be given of wafer processing performed using the wafer processing system 1 configured as above. In this embodiment, the first wafer W and the second wafer S are bonded together to form an overlapping wafer T in advance.

[0039] First, a cassette C containing a plurality of overlapping wafers T is placed on the cassette mounting table 10 of the carry-in / out station 2. Next, the overlapping wafers T are removed from the cassette C by the wafer transfer device 20 and transferred to the interface modification device 50 via the transition device 30 and the wafer transfer device 40.

[0040] In the interface modification device 50, first, the overlapped wafer T held by the chuck 100 is moved to a macro imaging position. The macro imaging position is a position where the macro camera 120 can capture an image of the outer edge of the first wafer W. At the macro imaging position, while the chuck 100 is being rotated, the macro camera 120 captures images of the outer edge of the first wafer W in a 360-degree circumferential direction. The captured images are output from the macro camera 120 to the control device 90.

[0041] The control device 90 calculates the amount of eccentricity between the center of rotation of the chuck 100 and the center of the first wafer W from the image captured by the macro camera 120. Furthermore, the control device 90 calculates the amount of movement of the chuck 100 based on the calculated amount of eccentricity so as to correct the Y-axis component of the amount of eccentricity. The control device 90 moves the chuck 100 horizontally along the Y-axis direction based on the calculated amount of movement.

[0042] Next, a predetermined irradiation area of ​​the interface laser light L1 is irradiated with pulsed interface laser light L1 from the laser head 110 to modify the interface between the first wafer W and the second wafer S (the interface between the first wafer W and the bonding film Fw in the illustrated example) as shown in FIGS. 3 and 6(a). Note that in the embodiment, "modification of the interface" includes, for example, amorphization of the device layer Dw or the bonding film Fw at the irradiation position of the interface laser light L1, and peeling of the first wafer W and the second wafer S. Furthermore, the interface between the first wafer W and the second wafer S where the unbonded area Ae is formed is not limited to the illustrated example; if the bonding strength between the first wafer W and the second wafer S can be reduced, the unbonded area Ae can be formed at any position inside the overlapped wafer T.

[0043] The irradiation area of ​​the interface laser light L1 is determined as an annular area having a desired radial width, for example, with the outer edge of the first wafer W as a reference. The radial width of the irradiation area is set to a width that allows appropriate removal of the peripheral edge We of the first wafer W to be removed. The position of the outer edge of the first wafer W that serves as the reference may be determined in advance based on the alignment position associated with the above-described movement of the chuck 100 in the Y-axis direction, or may be acquired based on the image capture result obtained by the above-described macro camera 120.

[0044] In the interface modification device 50, by modifying the irradiation position of the interface laser light L1 at the interface between the first wafer W and the second wafer S in this manner, an unbonded region Ae is formed in which the bonding strength between the first wafer W and the second wafer S is reduced (step St1 in FIG. 7). In the edge trimming described below, the peripheral edge We of the first wafer W, which is the removal target, is removed, and the presence of the unbonded region Ae in this manner makes it possible to appropriately remove the peripheral edge We.

[0045] When the unbonded region Ae is formed at the interface between the first wafer W and the second wafer S, an inspection is then performed to determine whether the unbonded region Ae has been properly formed at the interface (Step St2 in FIG. 7). The detailed inspection method in the interface modification apparatus 50 will be described later.

[0046] If it is determined in step St2 that the unbonded area Ae has not been formed properly, that is, for example, if it is determined that the formation width of the unbonded area Ae is larger than the radial width of the peripheral portion We to be removed and the unbonded area Ae has been formed radially inward from the planned position for forming the peripheral modified layer M1, then after the peripheral portion We is removed, the first wafer W will be floating relative to the second wafer S, which may cause particles, etc. to be generated in later processes. In such a case, the overlapped wafer T is carried out from the inside of the interface modification apparatus 50 by the wafer transfer device 40, and the next overlapped wafer T is carried into the inside of the interface modification apparatus 50. The overlapped wafer T carried out from the interface modification apparatus 50 is, for example, discarded or collected.

[0047] On the other hand, in step St2, if it is determined that the formation width of the unbonded area Ae is smaller than the radial width of the peripheral portion We to be removed and that the peripheral modified layer M1 has not been formed from the planned formation position to the set radial outer position, or if it is determined that there is a gap in part of the unbonded area Ae, the peripheral portion We cannot be properly peeled off in the unformed part of the unbonded area Ae, and part of the peripheral portion We may remain on the overlapped wafer T. 7, the interface laser light L1 is irradiated again to the unformed portion of the unbonded region Ae (step St1). In other words, the unbonded region Ae is reformed in the peripheral portion We to be removed. The conditions for reforming the unbonded region Ae may be fed back to the conditions for forming the unbonded region Ae (step St1) on the overlapped wafer T to be processed next in the wafer processing system 1.

[0048] The overlapped wafer T, which has been determined in step St2 to have an unbonded region Ae properly formed over the entire surface of the peripheral edge portion We to be removed, is then transferred by the wafer transfer device 40 to the internal reforming device 60.

[0049] In the internal reforming device 60, first, the overlapped wafer T held by the chuck 200 is moved to a macro imaging position. The macro imaging position is a position where the macro camera 220 can capture an image of the outer edge of the first wafer W. At the macro imaging position, while the chuck 200 is being rotated, the macro camera 220 captures images of the outer edge of the first wafer W in a 360-degree circumferential direction. The captured images are output from the macro camera 220 to the control device 90.

[0050] The control device 90 calculates the amount of eccentricity between the center of rotation of the chuck 200 and the center of the first wafer W from the image of the macro camera 220. The control device 90 also calculates the amount of movement of the chuck 200 based on the calculated amount of eccentricity so as to correct the Y-axis component of the amount of eccentricity. The control device 90 moves the chuck 200 horizontally along the Y-axis direction based on the calculated amount of movement. The control device 90 also identifies the position of the radially inner end (hereinafter simply referred to as the "inner end") of the unbonded region Ae formed by the interface modification device 50 from the image of the macro camera 220. The irradiation position of the internal laser light L2 is determined to be slightly radially inward from the inner end of the unbonded region Ae detected by the macro camera 220, for example.

[0051] Next, the laser head 210 irradiates the internal laser light L2 onto a predetermined irradiation position of the internal laser light L2, and as shown in FIGS. 3 and 6(b), a peripheral modified layer M1 and divided modified layers M2 are sequentially formed inside the first wafer W (step St3 in FIG. 7). The peripheral modified layer M1 serves as a base point for removing the peripheral portion We in the edge trimming described below. The divided modified layers M2 serve as base points for dividing the peripheral portion We into small pieces to be removed. In the drawings used in the following explanation, the divided modified layers M2 may be omitted to avoid complicating the illustrations.

[0052] When the peripheral modified layer M1 is formed, a crack C1 extends from the peripheral modified layer M1 inside the first wafer W in the thickness direction of the first wafer W. The upper end of the crack C1 reaches, for example, the surface Wa, as shown in FIG. 6(b). In this embodiment, the peripheral modified layer M1 is formed slightly radially inward from the inner edge of the unbonded region Ae, so that the bottom end of the crack C1 extends from the bottom end of the peripheral modified layer M1 formed at the bottom, for example, toward the inner edge of the unbonded region Ae, as shown in FIG.

[0053] After the peripheral modified layer M1 and the divided modified layers M2 are formed inside the first wafer W, an inspection is then performed to determine whether the peripheral modified layer M1 has been properly formed inside the first wafer W and whether the crack C1 has extended (step St4 in FIG. 7). The detailed inspection method in the internal modifying device 60 will be described later.

[0054] If it is determined in step St4 that the peripheral modification layer M1 (crack C1) is not properly formed, the peripheral portion We may not be properly peeled off in the unextended portion of the crack C1, and part of the peripheral portion We may remain on the overlapped wafer T. In this case, the unextended portion of the crack C1 is irradiated with the internal laser light L2. This forms a new peripheral modified layer M1 inside the first wafer W, and the crack C1 is extended between the inner edge of the unbonded region Ae and the lower end of the peripheral modified layer M1 via the new peripheral modified layer M1. The conditions for forming the new peripheral modified layer M1 may be fed back to the conditions for forming the peripheral modified layer M1 (step St3) on the next overlapped wafer T processed in the wafer processing system 1. Alternatively, in such a case, the overlapped wafer T is carried out from the interior of the internal reforming device 60 by the wafer transfer device 40, and the next overlapped wafer T is carried into the interior of the internal reforming device 60. The overlapped wafer T carried out from the internal reforming device 60 is, for example, discarded or collected.

[0055] The overlapped wafer T, for which it has been determined in step St4 that a peripheral modified layer M1 (crack C1) has been properly formed inside the first wafer W, is then transferred by the wafer transfer device 40 to the peripheral removal device 70. In the peripheral removal device 70, as shown in FIG. 6(c), removal of the peripheral portion We of the first wafer W, i.e., edge trimming, is performed (step St5 in FIG. 7). At this time, the peripheral portion We is peeled from the center portion Wc of the first wafer W using the peripheral modified layer M1 and the crack C1 as base points, and is also completely peeled from the second wafer S using the unbonded region Ae as base points. At this time, the removed peripheral portion We is also broken into small pieces using the divided modified layer M2 as base points.

[0056] In removing the peripheral edge portion We, for example, a wedge-shaped blade B (see FIG. 6(c)) may be inserted into the interface between the first wafer W and the second wafer S that form the overlapped wafer T.

[0057] Once the peripheral edge We of the first wafer W has been removed, an inspection is then performed to determine whether the peripheral edge We has been properly removed from the first wafer W (step St6 in FIG. 7). The detailed inspection method in the peripheral edge removing apparatus 70 will be described later.

[0058] In step St6, the peripheral area We is properly Removal If it is determined that the peripheral edge portion We has not been removed, that is, if a part of the peripheral edge portion We remains on the overlapped wafer T, this may cause the generation of particles or the like in subsequent processes. In this case, as shown in FIG. 7, the blade B may be inserted again into the unpeeled portion of the peripheral edge We (step St5). Alternatively, in this case, the overlapped wafer T may be carried out from the inside of the edge removing device 70 by the wafer transfer device 40, and the overlapped wafer T may be discarded or collected.

[0059] The overlapped wafer T, for which it has been determined in step St6 that the peripheral edge portion We of the first wafer W has been properly removed, is then transferred by the wafer transfer device 40 to the cleaning device 80. In the cleaning device 80, the first wafer W and / or the second wafer S after the peripheral edge portion We has been removed are cleaned (step St7 in FIG. 7).

[0060] Thereafter, the overlapped wafer T that has undergone all the processing is transferred by the wafer transfer device 20 to the cassette C on the cassette mounting table 10 via the transition device 30. In this way, a series of wafer processing steps in the wafer processing system 1 is completed.

[0061] In the above embodiment, the unbonded region Ae that reduces the bonding strength between the first wafer W and the second wafer S and the peripheral modified layer M1 that serves as a base point for peeling of the peripheral portion We are formed in this order, but the order in which they are formed is not particularly limited. That is, after the peripheral modified layer M1 is formed inside the first wafer W in the internal modification device 60, the unbonded region Ae may be formed at the interface between the first wafer W and the second wafer S in the interface modification device 50.

[0062] Next, a method for inspecting the unbonded region Ae in the interface modification apparatus 50 (step St2 in FIG. 7) will be described.

[0063] 8, when inspecting the unbonded area Ae, first, the chuck 100 is rotated and the micro camera 121 captures an image of the unbonded area Ae formed in step St1 in the circumferential direction of 360 degrees (step St2-1 in FIG. 10). The captured image is output from the micro camera 121 to the control device 90. The imaging width d1 of the unbonded area Ae in the radial direction by the micro camera 121 is determined by the width including at least the outer end (edge) of the first wafer W to the inner end of the unbonded area Ae.

[0064] 9, for example, the captured image shows that the area outside the outer edge of the first wafer W (outer area: left side in FIG. 9) is darker, and the area inside the inner edge of the unbonded area Ae (inner area: right side in FIG. 9) is brighter. Also, the area between the outer area and the inner area (intermediate area: center in FIG. 9), where the unbonded area Ae is formed, has a brightness that is approximately halfway between the outer area and the inner area.

[0065] The control device 90, which has received the output of the captured image, divides the intermediate region, which is the portion where the unbonded region Ae is formed, into a plurality of divided regions R (see FIG. 9) in at least one of the radial direction and the circumferential direction (in the illustrated example, both the radial direction and the circumferential direction) of the image of the unbonded region Ae in the 360-degree circumferential direction captured by the micro camera 121 (see FIG. 10 Step St2-2).

[0066] Next, for each of the plurality of divided regions R divided in step St2-2, statistical values ​​of the gray values, for example, the mean value (Mean) and standard deviation (Sigma), are calculated (step St2-3 in FIG. 10).

[0067] Next, based on the average value and standard deviation of the gray values ​​calculated in step St2-3, it is determined whether the unbonded region Ae has been properly formed in step St1 of FIG. 7, i.e., whether the unbonded region Ae has been properly formed around the entire circumference of the first wafer W, and whether the width of the unbonded region Ae is uniform around the entire circumference (step St2-4 of FIG. 10).

[0068] Specifically, when the unbonded area Ae is formed appropriately and with a uniform width around the entire circumference of the first wafer W, the average value and standard deviation of the gray values ​​obtained in each of the multiple divided areas R are considered to show approximately the same values.

[0069] Therefore, in this embodiment, if the average value and standard deviation of the gray values ​​calculated for each of the multiple divided regions R fall within a preset threshold, it is determined that the unbonded region Ae is properly formed around the entire periphery of the first wafer W. Note that the "threshold" according to this embodiment is a value determined to enable proper peeling of the peripheral edge portion We, and in one example, can be empirically determined based on the results of a previous process of the overlapped wafer T. On the other hand, if a divided area R is detected as a singular point where either the average value or standard deviation of the gray value exceeds the threshold, it is determined that the unbonded area Ae is not properly formed in the divided area R as the singular point.

[0070] Specifically, when a division region R is detected as a singular point where the average value or standard deviation of the gray values ​​exceeds the threshold value, it is determined that the interface laser light L1 was not focused at the interface between the first wafer W and the second wafer S in the division region R as the singular point due to factors such as the occurrence of light leakage, and that the unbonded region Ae was not properly formed. This is because, when an unbonded region Ae is formed at the same height inside the overlapped wafer T, the infrared light from the micro-camera 121 is reflected and received in the unbonded region Ae, that is, at the same height inside the overlapped wafer T. In other words, when the infrared light is reflected at the same height, the calculated gray value becomes approximately constant. Therefore, if the unbonded area Ae is not properly formed in part of the circumferential or radial direction of the first wafer W, for example, due to the influence of light leakage, specifically, if at least the unbonded area Ae is not formed at the same height, the reflection height of the infrared light from the micro camera 121 will change, which will change the average value or standard deviation calculated from the gray value, making it possible to detect that the unbonded area Ae is not properly formed.

[0071] If it is determined in step St2-4 that the unbonded region Ae is not properly formed, the overlapped wafer T is discarded or recovered, or the unbonded region Ae is reformed, as described above. On the other hand, if it is determined that the unbonded region Ae is properly formed, the series of inspections of the unbonded region Ae is terminated, and the overlapped wafer T is unloaded from the interface modification device 50.

[0072] According to this embodiment, the unbonded region Ae (modified state inside the overlapped wafer T) formed at the interface between the first wafer W and the second wafer S can be nondestructively inspected based on the gray values ​​of the image captured by the near-infrared camera. In other words, the state of the unbonded region Ae can be inspected in advance before removing (edge ​​trimming) the peripheral edge We of the first wafer W. As a result, if the unbonded region Ae that reduces the bonding strength between the first wafer W and the second wafer S is not properly formed, it is possible to determine whether to re-form the unbonded region Ae or discard or collect the overlapped wafer T in which the unbonded region Ae is formed, without peeling the peripheral edge We. As a result, the proportion of discarded wafers generated in the wafer processing system 1 can be reduced and throughput can be improved.

[0073] Furthermore, according to this embodiment, the micro camera 121 captures an image of the peripheral portion We of the first wafer W, on which the unbonded region Ae is formed, and then the state of formation of the unbonded region Ae can be easily inspected by simply comparing at least one of the average value and the standard deviation of the gray values ​​calculated by the control device 90 with a predetermined threshold. Since the inspection can be performed simply by comparing the calculated values ​​in this way, it is also easy to automatically control the inspection of the state of formation of the unbonded region Ae by the control device 90.

[0074] In the above embodiment, the formation state of the unbonded area Ae was inspected by comparing at least one of the average value and standard deviation of the calculated gray values ​​with a predetermined threshold value, but the comparison targets for these parameters are not limited to the predetermined threshold value. For example, instead of setting a threshold value for comparison in advance, parameters obtained when the unbonded area Ae was properly formed and the peripheral portion We was properly peeled off from another overlapped wafer T whose peripheral portion We was imaged (parameters calculated) before the inspection target overlapped wafer T may be used as the comparison target. In other words, the processing result of the other overlapped wafer T may be set as a threshold value and fed back to the processing conditions of the processing target overlapped wafer T. Also, for example, instead of comparing parameters of other overlapping wafers T or predetermined threshold values, gray values ​​obtained within the same surface of the overlapping wafer T to be inspected, i.e., in multiple divided regions R, may be compared with each other.

[0075] However, when gray values ​​are compared in this manner within the same plane of the overlapped wafer T, if the unbonded region Ae is not properly formed all over the entire periphery of the peripheral portion We, that is, if the unbonded region Ae is not properly formed in all divided regions R, there will be no difference in the comparison results, and it may not be possible to properly inspect the state of formation of the unbonded region Ae. In view of this, it is desirable to set a threshold value to be compared in advance, as shown in the above embodiment.

[0076] In the above embodiment, the inspection was performed by capturing an image of the unbonded region Ae using the micro camera 121 provided inside the interface modification device 50, but the imaging mechanism for capturing an image of the unbonded region Ae may be any camera that can properly view the unbonded region Ae. For example, if the macro camera 120 used for capturing an image of the outer edge of the first wafer W can be used, the micro camera 121 may be omitted from the configuration of the interface modification device 50. Alternatively, instead of performing the inspection inside the interface modification device 50, the inspection of the unbonded area Ae (step St2) may be performed using an inspection device (not shown) that is independently provided outside the interface modification device 50.

[0077] Next, a method for inspecting the formation state of the peripheral modified layer M1 and the extension state of the crack C1 (step St4 in FIG. 7 described above) will be described.

[0078] 11, during the inspection of the internal reforming device 60, the chuck 200 is rotated and the peripheral modified layer M1 and the crack C1 formed in step St3 are imaged in the circumferential direction 360 degrees by the micro camera 221 (step St4-1 in FIG. 16). The captured images are output from the micro camera 221 to the control device 90. The radial imaging width d2 of the micro camera 221 is determined by the width including at least the outer end (edge) of the first wafer W and the peripheral modified layer M1 and crack C1 formed inside the first wafer W.

[0079] 12, for example, the captured image shows that the area outside the outer edge of the first wafer W (outer area: left side in FIG. 12) is darker, and the area inside the position where the peripheral modified layer M1 is formed (inner area: right side in FIG. 12) is brighter. The area where the unbonded area Ae is formed (middle area: next to the outer area in FIG. 12) has a brightness approximately halfway between the outer and inner areas. Furthermore, the area where the peripheral modified layer M1 is formed (next to the inner area in FIG. 12) has a brightness approximately between the middle and inner areas because infrared light is reflected by the peripheral modified layer M1 formed at the top of the first wafer W. Furthermore, the area where the crack C1 extending between the bottom end of the peripheral modified layer M1 and the inner end of the unbonded area Ae is formed (between the area where the peripheral modified layer M1 is formed and the middle area in FIG. 12) does not receive infrared light irradiated by the coaxial incident-light method and is therefore darker than the outer area. In other words, due to the formation of the peripheral modified layer M1 and the crack C1, the image captured by the micro camera 221 has a dark area (crack C1) between the intermediate region and the inner region and a region of brightness approximately between the intermediate region and the inner region (peripheral modified layer M1) formed therein, compared to the image captured by the micro camera 121 in the above-mentioned step St2-1.

[0080] As shown in Figure 12, the control device 90 acquires a profile of the gray value distribution in a rectangular area Q1 extending radially of the first wafer W, which is part of the 360-degree circumferential image of the peripheral modification layer M1 and crack C1 captured by the micro camera 221 (step St4-2 in Figure 16). In the gray value distribution, the gray value changes in the boundary between the outer region and the middle region, and the middle region. and The gray value changes sharply at the boundary portion of the crack C1 formation area, the boundary portion between the crack C1 formation area and the peripheral modified layer M1 formation area, and the boundary portion between the peripheral modified layer M1 formation area and the inner region.

[0081] Next, the gray value distribution (vertical axis in FIG. 12) of one rectangular region Q1 acquired in step St4-2 is differentiated with respect to the radial position of the first wafer W (horizontal axis in FIG. 12) (step St4-3 in FIG. 16). This calculates the radial displacement of the gray value in one rectangular region Q1 shown in Figure 12, and as shown in Figure 13, a profile of the gray value displacement distribution is obtained, with peaks at the boundaries of each of the regions.

[0082] Next, based on the displacement distribution of one rectangular area Q1 acquired in step St4-3, the displacement height (EdgeHeight) and displacement width (EdgeWidth) in the one rectangular area Q1 shown in Figure 13 are calculated (step St4-4 in Figure 16).

[0083] The profile of the gray value distribution based on the image captured by the micro camera 221 is acquired over 360 degrees in the circumferential direction of the first wafer W. In other words, for each of a plurality of rectangular regions Q1, Q2, . . . , Qn that are set and aligned in the circumferential direction of the first wafer W as shown in Fig. 14, the average value and standard deviation of the gray values ​​in the gray value distribution, and the displacement height and displacement width in the displacement distribution are acquired and calculated.

[0084] Next, the average value and standard deviation of the gray values ​​obtained in the multiple rectangular regions Q1, Q2, ..., Qn, as well as the height and width of the gray value displacement are graphed with the horizontal axis representing the 360-degree circumferential position of the first wafer W, as shown in Figure 15 (step St4-5 in Figure 16).

[0085] Next, based on the relationship between the height and width of the created gray value displacement and the circumferential position of the first wafer W, it is detected whether a peripheral modification layer M1 has been formed around the entire circumference of the first wafer W in step St3 of Figure 7, and whether the crack C1 has properly extended around the entire circumference (steps St4-6 of Figure 16).

[0086] Specifically, when the peripheral modified layer M1 (cracks C1) is properly formed around the entire circumference of the first wafer W, the height and width of the gray value displacements acquired in the rectangular regions Q1, Q2, ..., Qn are considered to show similar trends. In other words, the height and width of the gray value displacements are considered to remain constant regardless of the circumferential position of the first wafer W.

[0087] Therefore, in this embodiment, if the displacement height and displacement width of the gray value displacement amount fall within a predetermined threshold value (second threshold value) around the entire circumference of the first wafer W, it is determined that the peripheral modified layer M1 and crack C1 are properly formed around the entire circumference of the first wafer W. On the other hand, if there is a singular point where either the displacement height or displacement width of the gray value displacement exceeds the threshold, it is determined that the peripheral modification layer M1 or crack C1 is not properly formed at the circumferential position corresponding to the singular point.

[0088] Specifically, if a singular point that deviates from the threshold value is detected in the displacement height of the gray value displacement, it is determined that the peripheral modified layer M1 or the crack C1 is not properly formed. This is because, when the peripheral modified layer M1 is properly formed around the entire circumference of the first wafer W, the reflection position (reflection height) of the infrared light from the micro camera 121 becomes approximately constant. Also, when the crack C1 extends properly around the entire circumference of the first wafer W, the reflection of the infrared light from the micro camera 121 is not detected around the entire circumference of the first wafer W. Therefore, for example, if the peripheral modified layer M1 is not properly formed in a portion of the circumferential direction, the gray value measured with the infrared light changes, the displacement height in the displacement distribution shifts, and it can be detected that the peripheral modified layer M1 formed at least at the uppermost level in the thickness direction of the first wafer W is not properly formed. Alternatively, for example, if the crack C1 does not extend properly in a portion of the circumferential direction, reflection of the infrared light is detected in a portion of the circumferential direction, and it can be detected that the crack C1 has not extended properly.

[0089] More specifically, if a singular point that deviates from the threshold value in the range of the amount of change in the gray value is detected, it is determined that the crack C1 is not properly formed. This is because the unreflected width of the infrared light from the micro camera 121 becomes constant when the crack C1 extends appropriately around the entire circumference of the first wafer W. In other words, when the width where the reflected infrared light cannot be detected is constant, the calculated displacement width becomes approximately constant. Therefore, for example, if the displacement width of the gray value changes due to a change in the unreflected width of infrared light, the peak position of the displacement distribution will shift, and it can be detected that the extension width of crack C1 is not constant, i.e., that crack C1 is not extending properly.

[0090] If it is determined in step St4-6 that the peripheral modified layer M1 or the crack C1 has not been properly formed, the overlapped wafer T is discarded or recovered, or the peripheral modified layer M1 or the crack C1 is reformed, as described above. In such a case, the conditions for forming the peripheral modified layer M1 and the crack C1 may be feedback-controlled to the processing conditions for the overlapped wafer T to be processed next in the wafer processing system 1. On the other hand, if it is determined that the unbonded region Ae is properly formed, the series of inspections for the peripheral modified layer M1 and the cracks C1 is ended, and the overlapped wafer T is carried out from the internal modifying device 60.

[0091] According to this embodiment, the peripheral modified layer M1 and cracks C1 formed inside the first wafer W can be nondestructively inspected based on the gray values ​​of an image captured by a near-infrared camera. In other words, the formation states of the peripheral modified layer M1 and cracks C1 can be inspected in advance prior to removing (edge ​​trimming) the peripheral portion We of the first wafer W. As a result, if the peripheral modified layer M1 or cracks C1, which serve as the starting point for peeling of the peripheral portion We, are not properly formed, it is possible to determine whether to reform the peripheral modified layer M1 or cracks C1 or to discard or recover the overlapped wafer T without peeling the peripheral portion We. As a result, the proportion of discarded wafers generated in the wafer processing system 1 can be reduced and throughput can be improved.

[0092] In this embodiment, in step St4, it was inspected whether the peripheral modified layer M1 and crack C1 were properly formed. However, as described above, for the peripheral modified layers M1 formed in multiple locations in the thickness direction of the first wafer W, it is not possible to detect the peripheral modified layers M1 formed in any location other than the topmost layer in the thickness direction using infrared light. In view of this, the inspection of the peripheral modified layer M1 may be omitted in step St4, and only the propagation state of the crack C1 may be inspected.

[0093] Furthermore, in the above embodiment, the peripheral modification layer M1 was formed at a position slightly radially inward from the inner end of the unbonded area Ae, thereby forming a crack C1 extending diagonally upward from the inner end of the unbonded area Ae. However, the peripheral modification layer M1 may also be formed at a radial position corresponding to the inner end of the unbonded area Ae, as shown in Figure 17. In this case, the crack C1 does not extend obliquely upward into the first wafer W, and therefore the above-described step St4, ie, the inspection of the peripheral modified layer M1 and the crack C1, may be omitted.

[0094] In the above embodiment, the inspection was performed by capturing images of the peripheral modified layer M1 and the crack C1 with the micro camera 221 provided inside the internal reforming device 60, but the imaging mechanism for capturing images of the peripheral modified layer M1 and the crack C1 may be the macro camera 220. In such a case, the micro camera 221 may be omitted from the configuration of the internal reforming device 60. Alternatively, instead of performing the inspection inside the internal reforming device 60, the peripheral modified layer M1 and the cracks C1 may be inspected using an inspection device (not shown) provided independently outside the internal reforming device 60. In such a case, the inspection device that inspects the peripheral modified layer M1 and the cracks C1 may further inspect the unbonded region Ae described above.

[0095] Next, a method for inspecting the removal status of the peripheral edge portion We (step St6 in FIG. 7 described above) will be described.

[0096] 18, during inspection in the edge removal device 70, first, while a chuck (not shown) is being rotated, an image of the outer edge of the first wafer W before removal of the edge portion We is captured in the circumferential direction of 360 degrees by the imaging mechanism 71 (e.g., a CCD camera) (step St6-0 in FIG. 23). In other words, in the edge removal device 70, an image of the first wafer W is captured prior to step St5 (edge ​​trimming) shown in FIG. 7. The captured image is output to the control device 90. The radial imaging width d3 of the imaging mechanism 71 is determined as a width including at least the width from the outer end (edge) of the first wafer W to the inner end (position where the peripheral modified layer M1 is formed) of the peripheral portion We to be removed.

[0097] In step St6-0, the imaging mechanism 71 images the back surface Wb of the first wafer W before the peripheral portion We is removed, and in the captured image, the outside of the first wafer W is darker than the outer edge, and the inside of the first wafer W is brighter than the outer edge, as shown in FIG.

[0098] Next, a blade B having, for example, a wedge shape is inserted into the interface between the first wafer W and the second wafer S that form the overlapped wafer T (see FIG. 6(c)), and the peripheral edge portion We is removed, i.e., edge trimming is performed (step St5 in FIGS. 7 and 23).

[0099] 20, after the peripheral edge portion We of the first wafer W has been removed, the outer edge of the first wafer W after the peripheral edge portion We has been removed is imaged in the circumferential direction of 360 degrees by the imaging mechanism 71 (e.g., a CCD camera) while rotating a chuck (not shown) (step St6-1 in FIG. 23). The captured image is output to the control device 90. The imaging width in the radial direction by the imaging mechanism 71 in step St6-1 is preferably the same as the imaging width d3 before the peripheral edge portion We is removed in step St6-0.

[0100] 21, the captured image shows that the area outside the outer edge of the first wafer W (outer area: left side in FIG. 21) is darker, and the area radially inside the outer edge of the first wafer W after removal of the peripheral edge We, i.e., the peeled surface of the peripheral edge We, is brighter (inner area: right side in FIG. 21). Furthermore, the area (intermediate area) that becomes the exposed surface of the second wafer S (bonding film Fw in the illustrated example) exposed by removal of the peripheral edge We has a brightness that is approximately halfway between the outer and inner areas. Furthermore, the inclined area (between the inner and intermediate areas) corresponding to the formation position of the crack C1 is darker than the outer area.

[0101] Next, the control device 90 calculates statistical values ​​of gray values, such as the mean value (Mean) and standard deviation (Sigma), in the annular region (see annular regions Z1 and Z2 in FIG. 22) corresponding to the peripheral edge We from the images of the outer peripheral edge of the first wafer W in the 360-degree circumferential direction taken in steps St6-0 and St6-1 (step St6-2 in FIG. 23).

[0102] Next, based on the average value and standard deviation of the gray values ​​calculated in step St6-2, it is determined whether the peripheral edge We has been properly removed from the first wafer W in the edge trimming in step St5 (step St6-3 in FIG. 23). Specifically, the difference in gray value between the outer edge of the first wafer W (annular region Z1 and annular region Z2) before and after removing the peripheral edge We obtained in step St6-2 is calculated.

[0103] When the peripheral edge We is properly removed around the entire circumference of the first wafer W, it is believed that the gray value of the annular region Z2 obtained from the imaging results after the peripheral edge We has been removed will have changed from the gray value of the annular region Z1 obtained from the imaging results before the peripheral edge We has been removed.

[0104] Therefore, in this embodiment, if a change in gray value is detected in such annular region Z1 and annular region Z2 around the entire circumference of the first wafer W, it is determined that the peripheral portion We has been properly removed around the entire circumference of the first wafer W. On the other hand, if no change in gray value occurs in a portion of the circumferential direction of the first wafer W, it is determined that the peripheral edge We has not been properly removed in the portion where the gray value has not changed.

[0105] If it is determined in step St6-3 that the peripheral edge We has not been properly removed, the blade B is inserted again into the unpeeled portion of the peripheral edge We, as described above. Alternatively, the overlapped wafer T is carried out from the interior of the peripheral edge removal device 70, and the overlapped wafer T is discarded or collected. On the other hand, if it is determined that the peripheral edge We has been properly removed, the series of inspections of the removal status of the peripheral edge We is ended, and the overlapped wafer T is carried out from the peripheral edge removal device 70.

[0106] According to this embodiment, it is possible to automatically inspect whether the peripheral edge We has been appropriately removed from the first wafer W without the need for an operator's judgment, based on the gray value of the image captured by the imaging mechanism 71. As a result, it is possible to improve the throughput of the wafer processing system 1.

[0107] In the above embodiment, whether the peripheral edge We has been properly removed is inspected by comparing the gray values ​​obtained from images taken inside the peripheral edge removal device 70 before and after edge trimming, but the inspection method is not limited to this. Specifically, instead of comparing the gray values ​​obtained from the image after edge trimming with the gray values ​​obtained from the image before edge trimming, it is also possible to inspect whether the peripheral edge We has been properly removed by using a threshold value (third threshold value) that has been acquired and set in advance when the peripheral edge We has been properly removed, in other words, that has been set based on the edge trimming results of another overlapping wafer T. In such a case, imaging of the outer edge of the first wafer W before edge trimming in the peripheral edge removing device 70 (step St6-0 in FIG. 23) can be omitted as appropriate.

[0108] In the above embodiment, the inspection is performed inside the edge removal device 70, but the inspection may be performed using an inspection device (not shown) that is provided independently outside the edge removal device 70. In such a case, the inspection device that inspects the removal status of the edge portion We may further inspect the unbonded region Ae and / or the edge modified layer M1 and cracks C1.

[0109] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive, and the above-described embodiments may be omitted, substituted, or modified in various ways without departing from the scope and spirit of the appended claims. [Explanation of symbols]

[0110] 1. Wafer Processing System 50 Interface Modification Equipment 60 Internal reformer 70 Edge removal device 90 Control device 121 Micro Camera Ae Unbonded area L1 Interface laser light M1 Peripheral Modification Layer S Second wafer T Polymerized Wafer W First wafer We Periphery

Claims

1. A method for treating a laminated substrate in which a first substrate and a second substrate are bonded, comprising: irradiating an interface between the first substrate and the second substrate with an interface laser light to form an unbonded region at the interface where bonding strength is reduced; inspecting the formation state of the unbonded region; forming a peripheral modification layer along a boundary between a peripheral portion of the first substrate and a central portion of the first substrate; removing the peripheral portion starting from the peripheral modified layer, The inspection of the formation state of the unbonded region includes: imaging the unbonded region with a camera; acquiring a distribution of gray values ​​in a plan view of the unbonded region from the captured image of the unbonded region for each of a plurality of divided regions set and aligned in at least one of a circumferential direction and a radial direction of the first substrate; and comparing the acquired gray value with a preset threshold value to inspect the formation state of the unbonded region.

2. A method for treating a polymerized substrate in which a first substrate and a second substrate are bonded, comprising: irradiating an interface between the first substrate and the second substrate with an interface laser light to form an unbonded region at the interface where bonding strength is reduced; inspecting the formation state of the unbonded region; forming a peripheral modification layer along a boundary between a peripheral portion of the first substrate and a central portion of the first substrate; removing the peripheral portion starting from the peripheral modified layer, The inspection of the formation state of the unbonded region includes: imaging the unbonded region with a camera; obtaining a distribution of gray values ​​in a planar view of the unbonded region from the captured image of the unbonded region; and comparing the acquired gray value with a preset threshold value to inspect the formation state of the unbonded region; A processing method, wherein the gray value parameter to be compared with the threshold value includes at least one of the average value and the standard deviation of the gray values ​​obtained from the captured image.

3. A method for treating a polymerized substrate in which a first substrate and a second substrate are bonded, comprising: irradiating an interface between the first substrate and the second substrate with an interface laser light to form an unbonded region at the interface where bonding strength is reduced; inspecting the formation state of the unbonded region; forming a peripheral modification layer along a boundary between a peripheral portion of the first substrate and a central portion of the first substrate; removing the peripheral portion starting from the peripheral modified layer, The inspection of the formation state of the unbonded region includes: imaging the unbonded region with a camera; obtaining a distribution of gray values ​​in a planar view of the unbonded region from the captured image of the unbonded region; and comparing the acquired gray value with a preset threshold value to inspect the formation state of the unbonded region; When forming the peripheral modified layer inside the first substrate, A crack is formed extending between the peripheral modification layer and the unbonded region, inspecting the formation state of at least one of the peripheral modification layer and the crack; The inspection of the peripheral modification layer or the crack formation state includes: Taking an image of the peripheral modification layer and the crack using a camera; acquiring a distribution of gray values ​​in a plan view of the first substrate from captured images of the peripheral modified layer and the crack; comparing the acquired gray value with a second preset threshold value to inspect whether the peripheral modification layer or the crack is formed around the entire periphery of the first substrate; A processing method in which the gray value parameters to be compared with the second threshold value include at least one of the average value, standard deviation, or height and radial width of the gray value displacement distribution obtained from the captured image.

4. The processing method according to claim 1 , further comprising comparing the gray values ​​obtained for each of the plurality of divided regions with each other.

5. The processing method according to claim 1 , wherein the gray value parameter to be compared with the threshold value includes at least one of an average value and a standard deviation of the gray values ​​obtained from the captured image.

6. When forming the peripheral modified layer inside the first substrate, A crack is formed extending between the peripheral modification layer and the unbonded region, The processing method according to claim 1 or 2, further comprising inspecting the state of formation of at least one of the peripheral modification layer and the crack.

7. The inspection of the peripheral modification layer or the crack formation state includes: Taking an image of the peripheral modification layer and the crack using a camera; acquiring a distribution of gray values ​​in a plan view of the first substrate from captured images of the peripheral modified layer and the crack; The processing method of claim 6, further comprising: inspecting whether the peripheral modification layer or the crack has formed around the entire periphery of the first substrate by comparing the acquired gray value with a second preset threshold value.

8. The processing method according to claim 7, wherein the gray value parameters to be compared with the second threshold value include at least one of the average value, standard deviation, height, and radial width of the gray value displacement distribution obtained from the captured image.

9. inspecting whether the peripheral portion to be removed has been removed from the laminated substrate; The inspection of the removal state of the peripheral portion includes: capturing an image of the edge of the first substrate after the peripheral edge portion is removed using a camera; acquiring a distribution of gray values ​​at a position corresponding to the peripheral edge portion in a plan view of the first substrate from a captured image of the edge portion of the first substrate after the peripheral edge portion has been removed; and comparing the distribution of gray values ​​after removal of the peripheral portion with a third threshold value set in advance to inspect whether the peripheral portion has been removed around the entire periphery of the first substrate.

10. capturing an image of the edge of the first substrate before removing the peripheral edge portion using a camera; acquiring a distribution of gray values ​​at a position corresponding to the peripheral edge portion in a plan view of the first substrate from a captured image of the edge portion of the first substrate before the peripheral edge portion is removed; The processing method according to claim 9 , wherein the third threshold is the distribution of gray values ​​obtained from an image of the edge of the first substrate before the peripheral edge portion is removed.

11. A processing system for processing a laminated substrate in which a first substrate and a second substrate are bonded together, comprising: an interface modification device that irradiates an interface between the first substrate and the second substrate with an interface laser light to form an unbonded region in which the bonding strength at the interface is reduced; an inspection device that inspects the formation state of the unbonded region; an internal modification device for forming a peripheral modification layer along a boundary between a peripheral portion of the first substrate and a central portion of the first substrate; a peripheral edge removing device that removes the peripheral portion starting from the peripheral modified layer; a control device; The control device, during the inspection by the inspection device, Control of capturing an image of the unbonded region using a camera; a control for acquiring a distribution of gray values ​​in a plan view of the unbonded region from the captured image of the unbonded region for each of a plurality of divided regions set and aligned in at least one of a circumferential direction or a radial direction of the first substrate; and a control for comparing the acquired gray value with a preset threshold.

12. A processing system for processing a polymerized substrate in which a first substrate and a second substrate are bonded together, comprising: an interface modification device that irradiates an interface between the first substrate and the second substrate with an interface laser light to form an unbonded region in which the bonding strength at the interface is reduced; an inspection device that inspects the formation state of the unbonded region; an internal modification device for forming a peripheral modification layer along a boundary between a peripheral portion of the first substrate and a central portion of the first substrate; a peripheral edge removing device that removes the peripheral portion starting from the peripheral modified layer; a control device; The control device, during the inspection by the inspection device, Control of capturing an image of the unbonded region using a camera; A control to acquire a distribution of gray values ​​in a planar view of the unbonded region from the captured image of the unbonded region; and comparing the obtained gray value with a preset threshold value. A processing system, wherein the gray value parameter to be compared with the threshold value includes at least one of the average value and the standard deviation of the gray values ​​obtained from the captured image.

13. A processing system for processing a polymerized substrate in which a first substrate and a second substrate are bonded together, comprising: an interface modification device that irradiates an interface between the first substrate and the second substrate with an interface laser light to form an unbonded region in which the bonding strength at the interface is reduced; an inspection device that inspects the formation state of the unbonded region; an internal modification device for forming a peripheral modification layer along a boundary between a peripheral portion of the first substrate and a central portion of the first substrate; a peripheral edge removing device that removes the peripheral portion starting from the peripheral modified layer; a control device; The control device, during the inspection by the inspection device, Control of capturing an image of the unbonded region using a camera; A control to acquire a distribution of gray values ​​in a planar view of the unbonded region from the captured image of the unbonded region; and comparing the obtained gray value with a preset threshold value. controlling the operation of the internal reforming device so that, when forming the peripheral modified layer, a crack propagates inside the first substrate between the peripheral modified layer and the unbonded region; and controlling the operation of the inspection device so as to inspect the formation state of at least one of the peripheral modified layer and the crack; When inspecting the peripheral modification layer or the crack, Control of capturing images of the peripheral modified layer and the crack using a camera; Control of acquiring a distribution of gray values ​​in a plan view of the first substrate from captured images of the peripheral modified layer and the crack; and comparing the acquired gray value with a second preset threshold value. The gray value parameters to be compared with the second threshold value include at least one of the average value, standard deviation, or height and radial width of the gray value displacement distribution obtained from the captured image.

14. The control device The processing system according to claim 11 , wherein control is executed to compare the gray values ​​acquired for each of the plurality of divided regions with each other.

15. The processing system according to claim 11 , wherein the gray value parameter to be compared with the threshold value includes at least one of an average value and a standard deviation of the gray values ​​acquired from the captured image.

16. The control device controlling the operation of the internal reforming device so that, when forming the peripheral modified layer, a crack propagates inside the first substrate between the peripheral modified layer and the unbonded region; The processing system according to claim 11 or 12, further comprising: a control for operating the inspection device so as to inspect the formation state of at least one of the peripheral modified layer and the crack.

17. When inspecting the peripheral modified layer or the crack, the control device Control of capturing images of the peripheral modified layer and the crack using a camera; Control of acquiring a distribution of gray values ​​in a plan view of the first substrate from captured images of the peripheral modified layer and the crack; and comparing the acquired gray value with a second preset threshold value.

18. 18. The processing system of claim 17, wherein the gray value parameters to be compared with the second threshold include at least one of the average value, standard deviation, or height and radial width of the gray value displacement distribution obtained from the captured image.

19. The control device executes control to operate the inspection device so as to inspect whether the peripheral portion to be removed has been removed from the laminated substrate; When inspecting the removal state of the peripheral portion, Control of capturing an image of the edge of the first substrate after the peripheral edge portion is removed using a camera; control of acquiring a distribution of gray values ​​at a position corresponding to the peripheral edge portion in a plan view of the first substrate from a captured image of the edge portion of the first substrate after the peripheral edge portion has been removed; The processing system according to any one of claims 11 to 15, further comprising a control for comparing the distribution of gray values ​​after the removal of the peripheral portion with a third preset threshold value.

20. The control device When inspecting the removal state of the peripheral portion, Control of capturing an image of the edge of the first substrate before removing the peripheral edge portion using a camera; and executing control to acquire a distribution of gray values ​​at a position corresponding to the peripheral edge portion in a plan view of the first substrate from a captured image of the edge portion of the first substrate before the peripheral edge portion is removed; The processing system of claim 19 , wherein the third threshold value is a distribution of gray values ​​obtained from an image of the edge of the first substrate before the peripheral edge is removed.

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