Substrate processing method and substrate processing system

Abstract

In an overlapping substrate in which a first substrate and a second substrate are bonded, a peripheral edge portion of the first substrate is appropriately removed in consideration of an unbonded region formed in a notch portion of the first substrate. A substrate processing method for processing an overlapping substrate in which a first substrate and a second substrate are bonded, the first substrate having: a notch formed by cutting a portion of a peripheral edge portion of the first substrate to be removed; a bonding portion bonded to the second substrate; and an unbonded portion that is not bonded to the second substrate, the substrate processing method including: irradiating a laser beam along a boundary between the peripheral portion of the first substrate and a central portion of the first substrate to form a peripheral modification layer that serves as a base point at which the peripheral portion is peeled off; and peeling the peripheral portion from the overlapping substrate on the basis of the peripheral modified layer, in which, when the peripheral modified layer is formed, the formation position of the peripheral modified layer corresponding to the portion where the notch is formed is determined on the basis of the information of the unbonded portion.

Description

Technical Field

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

[0002] Patent document 1 discloses a substrate processing system for processing a superimposed substrate formed by bonding a first substrate and a second substrate. The substrate processing system disclosed in Patent document 1 includes: an interface processing device for processing a bonding interface between the first substrate and the second substrate at a peripheral portion of the first substrate to be removed; a modified layer forming device for forming a modified layer inside the first substrate along a boundary between the peripheral portion and the central portion; and a peripheral edge removal device for removing the peripheral portion based on the modified layer.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2022-97506 Summary of the invention

[0006] Problem that the invention aims to solve

[0007] The technology according to the present disclosure appropriately removes the peripheral edge portion of the first substrate in consideration of the unbonded region formed at the notch portion of the first substrate in a superimposed substrate formed by bonding the first substrate and the second substrate.

[0008] Solutions for solving problems

[0009] One embodiment of the present disclosure is a substrate processing method for processing an overlapping substrate formed by bonding a first substrate and a second substrate, wherein the first substrate has: a notch formed by cutting off a portion of a peripheral portion of the first substrate to be removed; a bonded portion bonded to the second substrate; and an unbonded portion not bonded to the second substrate, the substrate processing method comprising: irradiating a laser beam along a boundary between the peripheral portion of the first substrate and a central portion of the first substrate to form a peripheral modification layer that serves as a base point for peeling off the peripheral portion; and peeling off the peripheral portion from the overlapping substrate with the peripheral modification layer as a base point, wherein when forming the peripheral modification layer, a formation position of the peripheral modification layer corresponding to the formation portion of the notch is determined based on information of the unbonded portion.

[0010] Effects of the Invention

[0011] According to the present disclosure, in a superimposed substrate formed by bonding a first substrate and a second substrate, the peripheral edge portion of the first substrate can be appropriately removed in consideration of the unbonded region formed at the notch portion of the first substrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is an enlarged side view showing a structural example of the stacked wafers according to the embodiment.

[0013] Figure 2 This is an explanatory diagram showing a structural example of a stacked wafer according to an embodiment in a plan view.

[0014] Figure 3 This is an explanatory diagram showing a structural example of a stacked wafer according to an embodiment in a side view.

[0015] Figure 4 It is a plan view schematically showing a configuration example of a wafer processing system according to an embodiment.

[0016] Figure 5 It is a plan view showing a configuration example of an interface reforming device and an internal reforming device.

[0017] Figure 6 It is a side view showing a configuration example of an interface reforming device and an internal reforming device.

[0018] Figure 7 It is an explanatory diagram showing the main steps of wafer processing according to the embodiment.

[0019] Figure 8 1 is a flowchart showing the main steps of forming the peripheral edge modification layer according to the embodiment.

[0020] Fig. 9 : is a graph showing the relationship between the circumferential position of the overlapped wafers and the eccentricity.

[0021] Fig.10 It is an explanatory diagram showing a peripheral edge modification layer formed by a conventional method.

[0022] Fig.11 It is an explanatory diagram showing a peripheral edge modification layer formed by the first mode according to the embodiment.

[0023] Fig.12 It is an explanatory diagram showing a peripheral edge modification layer formed by the first mode according to the embodiment.

[0024] Fig.13 It is an explanatory diagram showing a peripheral edge modification layer formed by the second mode according to the embodiment.

[0025] Fig.14 It is an explanatory diagram showing a peripheral edge modification layer formed by the third mode according to the embodiment.

[0026] Fig.15It is an explanatory diagram showing another formation example of the peripheral edge reforming layer formed by the third mode according to the embodiment.

[0027] Fig.16 It is an explanatory diagram showing another formation example of the peripheral edge reforming layer formed by the third mode according to the embodiment.

[0028] Fig.17 It is an explanatory diagram showing another formation example of the peripheral edge reforming layer formed by the third mode according to the embodiment.

[0029] Fig.18 It is an explanatory diagram showing another formation example of the peripheral edge reforming layer formed by the third mode according to the embodiment.

[0030] Fig.19 It is an explanatory diagram showing another formation example of the peripheral edge reforming layer formed by the third mode according to the embodiment.

[0031] Fig. 20 It is an explanatory diagram showing another formation example of the peripheral edge reforming layer formed by the third mode according to the embodiment.

[0032] Fig.21 : is a graph showing the relationship between the circumferential position and the eccentricity used in the process of overlapping wafers in the third mode according to the embodiment.

[0033] Fig. 22 It is an explanatory diagram showing an example of a method for forming a peripheral edge modification layer by the third mode according to the embodiment.

[0034] Fig.23 It is an explanatory diagram showing an example of a method for forming a peripheral edge modification layer by the third mode according to the embodiment.

[0035] Fig.24 This is an explanatory diagram showing the result of averaging the relationship between the circumferential position and the eccentricity of the overlapped wafers.

[0036] Fig.25 It is an explanatory diagram regarding the crystal orientation of the first wafer. DETAILED DESCRIPTION

[0037] In the manufacturing process of semiconductor devices, the peripheral edge of the first wafer having a plurality of electronic circuits and other devices formed on the surface is sometimes removed from the overlapped wafer formed by bonding two semiconductor substrates (hereinafter referred to as "wafers"), i.e., edge trimming is performed.

[0038] The edge trimming of the first wafer is performed, for example, using a wafer processing system (substrate processing system) disclosed in Patent Document 1. A modified layer is formed by irradiating a laser beam into the interior of the first wafer (first substrate), and the peripheral portion is removed from the first wafer based on the modified layer. In addition, the bonding force at the interface between the first wafer and the second wafer is reduced by performing a desired treatment on the interface where the first wafer and the second wafer meet, thereby achieving appropriate removal of the peripheral portion.

[0039] In addition, the end of the first wafer W including the peripheral portion We to be removed by edge trimming is chamfered so that the thickness decreases toward the front end (see Figure 1 ). Therefore, in the overlapped wafer formed by bonding the first wafer W and the second wafer S, the first wafer W and the second wafer S do not contact each other in the chamfered portion where the thickness is reduced, and are not bonded. In addition, even in the area radially inward of the chamfered portion, an area where the first wafer W and the second wafer S are not bonded may occur due to various factors such as the result of wafer processing in the previous process, the conditions when bonding the first wafer W and the second wafer S, and the like.

[0040] In the following description, in the overlapped wafer T formed by bonding the first wafer W and the second wafer S, a portion where the first wafer W and the second wafer S are not bonded is sometimes referred to as an “unbonded portion”, and a portion where the first wafer W and the second wafer S are bonded is sometimes referred to as a “bonded portion”.

[0041] In addition, as described above, the unbonded portion may be generated at a position radially inward of the chamfered portion of the first wafer W. However, in order to avoid complicating the description, Figure 1 and Figure 2 As shown, the unjoined portion corresponding to the chamfered portion is sometimes expressed as "unjoined area Ae", the joined portion located radially inside the unjoined area Ae is expressed as "joined area Ac", and the boundary portion between the unjoined area Ae and the joined area Ac is expressed as "boundary Ad".

[0042] In the unbonded area Ae, the first wafer W and the second wafer S are not bonded. Therefore, when edge trimming is performed in the unbonded area Ae, the first wafer W may float from the second wafer S at the interface of the overlapping wafers T after the edge trimming, which may cause chipping in subsequent processes.

[0043] Here, a notch Wn for indicating the direction of crystal orientation is formed in the peripheral edge portion We of the first wafer W as the semiconductor substrate from the outer end of the first wafer W toward the radial inner side. Figure 2As shown in FIG. 1 , when viewed from above, an unbonded portion is formed along the notch Wn, and therefore, the unbonded region Ae is formed to a position radially inward compared to the portion where the notch Wn is not formed. Therefore, when a certain trimming width is set from the outer end of the wafer without the notch Wn, edge trimming may be performed in the unbonded portion at the portion where the notch Wn is formed, resulting in a state where the first wafer W floats from the second wafer S, which may cause edge collapse in the subsequent process.

[0044] The technology disclosed herein is completed in view of the above situation. In the overlapping substrate formed by bonding the first substrate and the second substrate, the peripheral portion of the first substrate is appropriately removed by considering the unbonded area formed at the notch portion of the first substrate. Below, a wafer processing system as a substrate processing system involved in this embodiment and a wafer processing method as a substrate processing method are described with reference to the accompanying drawings. In addition, in this specification and the accompanying drawings, the same reference numerals are marked for elements having substantially the same functional structure, thereby omitting repeated descriptions.

[0045] In the wafer processing system 1 described later according to this embodiment, Figure 1 and Figure 3 As shown, a stacked wafer T as a stacked substrate formed by bonding a first wafer W as a first substrate and a second wafer S as a second substrate is processed. In the following, in the first wafer W, the surface on the side bonded to the second wafer S is referred to as the front surface Wa, and the surface on the side opposite to the surface Wa is referred to as the back surface Wb. Similarly, in the second wafer S, the surface on the side bonded to the first wafer W is referred to as the front surface Sa, and the surface on the side opposite to the surface Sa is referred to as the back surface Sb.

[0046] The first wafer W is a semiconductor substrate such as a silicon substrate, and a device layer Dw including a plurality of devices is formed on the surface Wa side. In addition, a bonding film Fw is formed on the device layer Dw, and the device layer Dw is bonded to the second wafer S by the bonding film Fw. As the bonding film Fw, for example, an oxide film (THOX film, SiO2 film, TEOS film), SiC film, SiCN film or adhesive is used. In addition, as Figure 1 As shown, the peripheral edge We of the first wafer W is chamfered, and the thickness of the cross section of the peripheral edge We decreases as it goes toward the front end. In addition, the peripheral edge We is a portion removed in the edge trimming described later, for example, a range of 0.5 mm to 3 mm in the radial direction from the outer end of the first wafer W.

[0047] In addition, if Figure 2As shown, a notch Wn indicating the crystal orientation is formed at the peripheral edge We of the first wafer W. In one example, the notch Wn is a notch formed by cutting off a portion of the outer end of the first wafer W. In addition, the shape of the notch Wn is not limited to Figure 2 The substantially triangular shape shown may be formed into, for example, a substantially elliptical shape or a substantially circular shape.

[0048] The second wafer S has, for example, the same structure as the first wafer W, with a device layer Ds and a bonding film Fs formed on the surface Sa, and a chamfering process and a notch formed on the peripheral edge. In addition, the second wafer S does not need to be a device wafer with a device layer Ds formed thereon, and may be, for example, a supporting wafer that supports the first wafer W.

[0049] like Figure 4 As shown, the wafer processing system 1 has a structure in which a loading and unloading station 2 and a processing station 3 are connected as one body. A front-opening wafer pod F capable of accommodating a plurality of stacked wafers T is loaded and unloaded, for example, from the outside through the loading and unloading station 2. The processing station 3 has various processing devices for performing desired processing on the stacked wafers T.

[0050] A FOUP stage 10 for placing a FOUP F that can accommodate a plurality of stacked wafers T is provided at the loading / unloading station 2. In addition, a wafer transfer device 20 is provided adjacent to the FOUP stage 10 on the positive X-axis side of the FOUP stage 10. The wafer transfer device 20 is configured to be movable on a transfer path 21 extending in the Y-axis direction and to transfer stacked wafers T between the FOUP F on the FOUP stage 10 and a transfer device 30 described later.

[0051] A transfer device 30 for transferring the overlapped wafers T to and from the processing station 3 is provided adjacent to the wafer transfer device 20 at the loading / unloading station 2 on the positive X-axis direction side of the wafer transfer device 20 .

[0052] The processing station 3 is provided with a wafer transfer device 40 , an interface modification device 50 , an internal modification device 60 , a peripheral edge removal device 70 , and a cleaning device 80 .

[0053] The wafer transfer device 40 is provided on the positive X-axis direction side of the conveyor device 30. The wafer transfer device 40 is configured to be freely movable on a transfer path 41 extending along the X-axis direction, and is configured to be able to transfer the overlapping wafers T to the conveyor device 30, the interface modification device 50, the internal modification device 60, the peripheral edge removal device 70, and the cleaning device 80 that are loaded and unloaded from the station 2.

[0054] The interface modification device 50 irradiates a laser beam (interface laser beam, such as a CO2 laser) to the interface between the first wafer W and the second wafer S to form a bonding force reduction region R where the bonding force between the first wafer W and the second wafer S is reduced (see below). Figure 7 ).

[0055] like Figure 5 and Figure 6 As shown, the interface modification device 50 has a holding disk 100 as a substrate holding portion for holding the overlapping wafers T through the upper surface. The holding disk 100 holds the overlapping wafers T by suction. The holding disk 100 can hold the back side Wb of the first wafer W by suction, and can also hold the back side Sb of the second wafer S by suction. The holding disk 100 is supported on the slide table 102 by the air bearing 101. A rotating mechanism 103 is provided on the lower surface side of the slide table 102. The rotating mechanism 103, for example, has a built-in motor as a driving source. The holding disk 100 is configured to rotate freely around the vertical axis through the rotating mechanism 103 through the air bearing 101. The slide table 102 is configured to move freely on a guide rail 106 provided on a base 105 and extending in the Y-axis direction by means of a moving mechanism 104 provided on the lower surface side thereof. In addition, there is no particular limitation on the driving source of the moving mechanism 104, for example, a linear motor is used.

[0056] A laser head 110 is provided above the holding disk 100. The laser head 110 has a lens 111. The lens 111 is a cylindrical member provided on the lower surface of the laser head 110, and irradiates the interface laser beam as the second laser beam to the inside of the overlapping wafers T held on the holding disk 100, more specifically, to the interface between the first wafer W and the second wafer S. As a result, the portion of the overlapping wafer T irradiated with the interface laser beam is modified to form a bonding force reduction region R where the bonding force between the first wafer W and the second wafer S is reduced. In addition, in the technology involved in the present disclosure, these laser heads 110 and lenses 111 are sometimes collectively referred to as a "laser irradiation unit".

[0057] The laser head 110 is supported by a support member 112. The laser head 110 is configured to be freely raised and lowered along a guide rail 113 extending in the vertical direction by a lifting mechanism 114. In addition, the laser head 110 is configured to be freely movable in the Y-axis direction by a moving mechanism 115. In addition, the lifting mechanism 114 and the moving mechanism 115 are respectively supported by a support column 116.

[0058] A macro camera 120 and a micro camera 121 are provided above the holding disk 100 and on the positive Y-axis side of the laser head 110. For example, the macro camera 120 and the micro camera 121 are integrally formed, and the macro camera 120 is arranged on the positive Y-axis side of the micro camera 121. The macro camera 120 and the micro camera 121 are configured to be freely raised and lowered by a lifting mechanism 122, and are configured to be freely moved in the Y-axis direction by a moving mechanism 123. In addition, in the technology involved in the present disclosure, the macro camera 120 and the micro camera 121 are sometimes collectively referred to as a "camera".

[0059] The macro camera 120 captures the outer end of the first wafer W (overlapping wafer T). As an example, the image captured by the macro camera 120 is used for the alignment of the first wafer W described later. The macro camera 120, for example, has a coaxial lens, irradiates infrared light (IR) and receives reflected light from an object. In one example, the imaging magnification of the macro camera 120 is 2 times.

[0060] The micro camera 121 photographs the peripheral portion We of the first wafer W and the boundary Ad between the bonding area Ac and the unbonded area Ae. As an example, the image captured by the micro camera 121 is used to determine the irradiation position of the interface laser beam. The micro camera 121, for example, has a coaxial lens, irradiates infrared light (IR light) and receives reflected light from the object. In one example, the imaging magnification of the micro camera 121 is 10 times, the field of view is about 1 / 5 of the field of view of the macro camera 120, and the pixel size is about 1 / 5 of the pixel size of the macro camera 120.

[0061] In addition, in the example shown in the figure, two cameras, namely, the macro camera 120 and the micro camera 121, are configured, but the number of cameras provided in the interface modification device 50 is not limited thereto, and any number of cameras may be configured in the interface modification device 50. For example, when the boundary Ad between the bonding area Ac and the unbonded area Ae is known in advance and it is not necessary to capture the boundary Ad, the configuration of the micro camera 121 may be omitted.

[0062] In the example shown in the figure, the holding plate 100 is configured to be relatively rotatable and horizontally movable with respect to the laser head 110 by the rotating mechanism 103 and the moving mechanism 104, but the laser head 110 may be relatively rotatable and horizontally movable with respect to the holding plate 100. In addition, the holding plate 100 and the laser head 110 may be configured to be relatively rotatable and horizontally movable with respect to each other.

[0063] The internal modification device 60 irradiates the inside of the first wafer W with a laser beam (internal laser beam, such as a YAG laser) to form a peripheral modification layer M1 that becomes a base for peeling off the peripheral portion We, and a segmentation modification layer M2 that becomes a base for fragmenting the peripheral portion We. The structure of the internal modification device 60 is not particularly limited. In one example, Figure 5 and Figure 6 As shown, the internal modification device 60 has the same structure as the interface modification device 50, and comprises: a holding disk 100, on the upper surface of which the overlapping wafers T are held; a rotating mechanism 103, which causes the holding disk 100 and the overlapping wafers T (first wafer W) to rotate relative to each other; a moving mechanism 104, which causes the holding disk 100 and the overlapping wafers T (first wafer W) to move relative to each other in the horizontal direction; a laser irradiation unit (laser head and lens), which irradiates an internal laser beam to the inside of the first wafer W held on the holding disk 100; and a camera, which photographs the overlapping wafers T held on the holding disk 100, and the like.

[0064] In the example shown in the figure, the interface modification device 50 and the internal modification device 60 are independently arranged inside the wafer processing system 1, but these interface modification devices 50 and internal modification devices 60 may be integrally configured. In other words, it may be configured such that only one modification device (not shown) is arranged in the wafer processing system 1, and the laser irradiation unit of the one modification device can switchably output the interface laser beam and the internal laser beam and irradiate.

[0065] The peripheral edge removal device 70 removes the peripheral edge portion We of the first wafer W, i.e., trims the edge, based on the peripheral edge modification layer M1 formed by the internal modification device 60. The edge trimming method can be selected arbitrarily. In one example, in the peripheral edge removal device 70, for example, a blade configured in a wedge shape can also be inserted into the interface between the first wafer W and the second wafer S. In addition, for example, the peripheral edge portion We can also be impacted by spraying air or water toward the peripheral edge portion We.

[0066] The cleaning device 80 performs a cleaning process on the first wafer W and the second wafer S after edge trimming by the peripheral edge removal device 70 to remove particles on these wafers. The cleaning method can be arbitrarily selected.

[0067] A control device 90 is provided for the above wafer processing system 1. 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 overlapping wafers T in the wafer processing system 1. In addition, the program storage unit also stores a program for controlling the operation of the drive system of the various processing devices, conveying devices, etc. mentioned above to realize the wafer processing described later in the wafer processing system 1. In addition, the above program can be recorded in a computer-readable storage medium H and installed from the storage medium H to the control device 90. In addition, the above storage medium H can be transient or non-transient.

[0068] The wafer processing system 1 according to one embodiment is configured as described above, but the configuration of the wafer processing system 1 is not limited to the illustrated example.

[0069] Next, the following describes how to use Figure 4 Wafer processing performed by the wafer processing system 1 having such a configuration. In the present embodiment, the first wafer W and the second wafer S are bonded in advance to form a superimposed wafer T.

[0070] First, a front-loading FOUP F storing a plurality of stacked wafers T is placed on the front-loading FOUP placement table 10 of the loading / unloading station 2 .

[0071] Next, the stacked wafers T are taken out from the front-opening FOUP F by the wafer transfer device 20 and are transferred to the interface modification device 50 via the transfer device 30 .

[0072] In the interface modification device 50, while rotating the overlapped wafer T (first wafer W) and moving horizontally along the Y-axis direction, the interface laser beam L1 is irradiated in a pulsed manner at the inside of the overlapped wafer T, specifically at the interface between the first wafer W and the second wafer S, at a position corresponding to the set trimming width of the peripheral portion We from the outer end of the first wafer W. As a result, as Figure 7 As shown in (a), the interface between the first wafer W and the second wafer S (in the example shown in the figure, the interface of the bonding films Fw and Fs) is modified. The modification of the bonding interface in the embodiment includes amorphization of the bonding film Fw at the irradiation position of the interface laser beam L1, peeling of the interface between the first wafer W and the second wafer S, etc.

[0073] In the interface modification device 50, the interface remaining at the interface between the first wafer W and the second wafer S is modified at the irradiation position of the laser beam L1, more specifically, at the bonding portion of the peripheral portion We, thereby forming a bonding force reduction region R where the bonding strength between the first wafer W and the second wafer S is reduced. In the edge trimming described later, the peripheral portion We of the first wafer W to be removed is removed, and the presence of the bonding force reduction region R allows the peripheral portion We to be appropriately removed.

[0074] In addition, when the set trimming width is set to the boundary Ad of the outer peripheral portion of the first wafer W where the groove Wn is not formed, that is, when it is set to the same width as the unbonded area Ae corresponding to the chamfered portion of the first wafer W, the formation process of the bonding force reduction area R in the interface modification device 50 can be omitted.

[0075] In addition, Figure 7 In (a), the case where the back side Sb of the second wafer S is held by the holding disk 100 and the interface is irradiated with the laser beam L1 from the back side Wb of the first wafer W is illustrated as an example, but it can also be set that the back side Wb of the first wafer W is held by the holding disk 100 and the interface is irradiated with the laser beam L1 from the back side Sb of the second wafer S.

[0076] Next, the wafer transfer device 40 transfers the overlapped wafer T in which the bonding force reduction region R is formed at the interface between the first wafer W and the second wafer S to the internal reforming device 60 .

[0077] In the internal reforming device 60, as Figure 7 As shown in (b), the interior of the first wafer W is irradiated with an internal laser beam L2 to form a peripheral modified layer M1 and a split modified layer M2. The peripheral modified layer M1 becomes the base point when the peripheral portion We is removed in the edge trimming described later. The split modified layer M2 becomes the base point for fragmenting the removed peripheral portion We. In addition, from the peripheral modified layer M1 and the split modified layer M2 formed by irradiating the internal laser beam L2, a crack C extends along the thickness direction of the first wafer W. Similar to the peripheral modified layer M1 and the split modified layer M2, the crack C becomes the base point when the peripheral portion We is removed and when the peripheral portion We is fragmented. In addition, in the drawings used in the subsequent description, in order to avoid complicating the illustration, the illustration of the split modified layer M2 is sometimes omitted.

[0078] In addition, a detailed method of forming the peripheral modified layer M1 by the internal reforming device 60 will be described later.

[0079] Next, the wafer transfer device 40 transfers the superimposed wafer T in which the peripheral edge reforming layer M1 and the divided reforming layer M2 are formed inside the first wafer W to the peripheral edge removing device 70 .

[0080] In the peripheral edge removal device 70, as Figure 7 The peripheral portion We of the first wafer W is removed, i.e., the edge is trimmed, as shown in (c). At this time, the peripheral portion We is peeled off from the central portion (radially inner side of the peripheral portion We) of the first wafer W with the peripheral modified layer M1 as the base point, and is completely peeled off from the second wafer S with the bonding force reduction area R as the base point. In addition, at this time, the removed peripheral portion We is fragmented with the split modified layer M2 as the base point. When removing the peripheral portion We, a blade B (see, for example, a wedge-shaped blade) may be inserted into the interface between the first wafer W and the second wafer S forming the overlapping wafer T. Figure 7 (c)).

[0081] Next, the overlapped wafer T from which the peripheral edge portion We of the first wafer W has been removed is transported to the cleaning device 80 by the wafer transport device 40 .

[0082] In the cleaning device 80, the first wafer W and / or the second wafer S from which the peripheral edge portion We has been removed are cleaned. Figure 7 As shown in (d), for example, the first wafer W and the second wafer S may be irradiated with the cleaning laser beam L3 to modify and remove the irradiated portion of the cleaning laser beam L3, thereby removing (cleaning) the remaining particles and the like.

[0083] Thereafter, the stacked wafers T that have been subjected to all the processing are transferred by the wafer transfer device 20 to the FOUP F on the FOUP stage 10 via the transfer device 30 . In this way, a series of substrate processing in the wafer processing system 1 is completed.

[0084] Next, a detailed method of forming the reduced bonding force region R and the peripheral modified layer M1 by the interface modifying device 50 and the internal modifying device 60 will be described with reference to the drawings.

[0085] First, in the interface modification device 50, the stacked wafers T held on the holding plate 100 are moved to the macro imaging position. The macro imaging position is a position where the macro camera 120 can capture the outer end of the first wafer W. At the macro imaging position, the image of the outer end of the first wafer W in the circumferential direction of 360 degrees is captured by the macro camera 120 while the holding plate 100 is rotated ( Figure 8 The captured image is output from the macro camera 120 to the control device 90 .

[0086] In the control device 90, the position of the notch Wn formed in the first wafer W held on the holding plate 100 is determined based on the image of the macro camera 120, and the eccentricity between the rotation center of the holding plate 100 and the center of the first wafer W is calculated. In one example, Fig. 9 As shown, the eccentricity between the rotation center of the holding disk 100 and the center of the first wafer W is output in the form of a waveform (sine curve) representing the relationship between the circumferential position of the first wafer W (horizontal axis in the figure) and the eccentricity (vertical axis in the figure).

[0087] Then, the control device 90 calculates the movement amount of the holding plate 100 based on the calculated eccentricity to correct the Y-axis component of the eccentricity. The control device 90 moves the holding plate 100 horizontally along the Y-axis direction based on the calculated movement amount to move the holding plate 100 to the microscopic imaging position ( Figure 8 Step St2: Alignment). The micro imaging position is a position where the micro camera 121 can capture the unbonded area Ae of the first wafer W.

[0088] Next, while rotating the holding plate 100, the micro camera 121 is used to photograph the unbonded region Ae of the first wafer W in the 360-degree circumferential direction, more specifically, the boundary Ad between the bonded region Ac and the unbonded region Ae of the first wafer W in the 360-degree circumferential direction ( Figure 8 Step St3: photographing the boundary Ad). The photographed image is output from the micro camera 121 to the control device 90.

[0089] In the control device 90, the irradiation position of the interface laser beam L1 for forming the bonding force reduction region R and the irradiation position of the internal laser beam L2 for forming the peripheral modified layer M1 are set based on the image of the macro camera 120 and the image of the micro camera 121 ( Figure 8 Step St4: setting the irradiation position). Specifically, in the control device 90, the irradiation position of the internal laser beam L2 is set with a predetermined trimming width (distance from the predetermined outer end) based on the position of the outer end of the first wafer W obtained from the image of the macro camera 120, and the bonding area Ac of the first wafer W and the second wafer S radially outward from the irradiation position of the internal laser beam L2 is set as the irradiation area of ​​the interface laser beam L1. In addition, in the control device 90 involved in the present embodiment, when setting the irradiation positions of the interface laser beam L1 and the internal laser beam L2, the unbonded area Ae formed corresponding to the notch Wn formed in the peripheral portion We of the first wafer W is considered. In other words, at the non-formed portion of the notch Wn, the irradiation position of the laser beam is set with a predetermined trimming width as described above, and on the other hand, at the formed portion of the notch Wn, the irradiation position of the laser beam is set in a manner that avoids the unbonded area Ae corresponding to the notch Wn as described later.

[0090] In addition, in the interface modification device 50, the irradiation position of the internal laser beam L2 (the formation position of the peripheral modified layer M1) is set with a predetermined trimming width based on the position of the outer end of the first wafer W obtained from the image of the macro camera 120. However, the method for determining the irradiation position of the internal laser beam L2 is not limited to this. For example, the irradiation position of the internal laser beam L2 (the formation position of the peripheral modified layer M1) may be set based on the boundary Ad obtained from the image of the micro camera 121 to coincide with the boundary Ad, or at least to a position radially inward of the boundary Ad.

[0091] Then, in the interface modification device 50, the interface laser beam L1 is irradiated to the set irradiation area to form a bonding force reduction area R ( Figure 8 Step St5: forming a peripheral modified layer M1).

[0092] The overlapped wafers T formed with the bonding force reduction region R are transported to the internal modification device 60. In the internal modification device 60, first, the overlapped wafers T held on the holding plate 100 are moved to the macro imaging position, and the image of the outer end of the first wafer W in the 360-degree circumferential direction is captured by the macro camera 120 ( Figure 8 The captured image is output from the macro camera 120 to the control device 90 .

[0093] The control device 90 determines the position of the notch Wn formed in the first wafer W held on the holding plate 100 based on the image of the macro camera 120 , and calculates the eccentricity between the rotation center of the holding plate 100 and the center of the first wafer W.

[0094] In the internal modification device 60, the holding plate 100 is moved in the horizontal direction based on the calculated eccentricity to correct the Y-axis component of the eccentricity, thereby correcting the eccentricity between the rotation center of the holding plate 100 and the center of the first wafer W, and irradiating the first wafer W with the internal laser beam L2 along the set irradiation position to form the peripheral modification layer M1 ( Figure 8 Step St7: forming a peripheral modified layer M1).

[0095] Here, in the conventional edge trimming, the irradiation positions of the interface laser beam L1 and the internal laser beam L2 are sometimes determined to be concentric circles separated from the outer end of the first wafer W by a desired distance on the entire circumference of the first wafer W. In other words, in the conventional edge trimming, the peripheral portion We is sometimes removed with a predetermined trimming width without considering the unbonded area Ae formed corresponding to the notch Wn formed on the first wafer W. However, in this case, as Fig.10As shown, the bonding force reduction region R and the peripheral reforming layer M1 are formed in the unbonded region Ae and in the portion corresponding to the notch Wn. However, the unbonded region Ae may remain in the overlapped wafers T after edge trimming, which may cause edge chipping in subsequent steps.

[0096] Therefore, in the wafer processing involved in the present embodiment, the bonding force reduction region R and the peripheral modified layer M1 that become the base point of peeling of the peripheral portion We in the edge trimming are formed in consideration of the unbonded region Ae corresponding to the notch Wn formed in the first wafer W. Next, the detailed setting method of the irradiation position of the interface laser beam L1 and the internal laser beam L2 is described based on the following first mode (A) to third mode (C).

[0097] <First Mode (A): Center Shift>

[0098] In the first mode (A), first, the outer end position of the first wafer W on the holding plate 100 is determined based on the image of the macro camera 120. Next, the position of the unbonded area Ae formed at a position corresponding to the notch Wn is determined, for example, over 360 degrees in the circumferential direction of the first wafer W based on information pre-acquired during the inspection of the bonding of the first wafer W and the second wafer S and stored in the storage unit of the control device 90 or based on the image of the micro camera 121, and the portion of the unbonded area Ae with the largest radial width (hereinafter referred to as "reference point P") is determined based on the outer end of the non-formed portion of the notch Wn. Refer to Fig.11 ). In other words, in the radial direction of the first wafer W, a reference point P is determined based on information acquired in advance or information captured by a camera, and the reference point P is located at the innermost unbonded portion (unbonded area Ae) corresponding to the notch Wn. In addition, the information acquired in advance during the inspection of the bonding of the first wafer W and the second wafer S can be input into the storage unit of the control device 90 by the operator, or can be input into the storage unit of the control device 90 from the inspection device via a main computer of a factory, etc.

[0099] Next, in the first mode (A), if Fig.11 As shown, the center position of the formation circle of the peripheral modified layer M1, which is predetermined to be formed concentrically with the first wafer W when viewed from above, is moved (offset) from the center position of the first wafer W, thereby preventing the peripheral modified layer M1 from being formed in the unbonded area Ae radially outside the boundary Ad.

[0100] More specifically, first, based on the trimming width d1, which is the removal width of the peripheral portion We determined in advance according to the purpose of wafer processing, the distance d2 from the trimming width d1 to the reference point P is calculated. For example, the distance d2 can be calculated by the difference between the distance dmax from the outer end of the first wafer W to the reference point P, which is obtained in advance or from the image of the micro camera 121, and the trimming width d1.

[0101] Next, the calculated distance d2 is set as the offset of the center position of the formation circle of the peripheral modification layer M1 relative to the center of the first wafer W, so that the internal irradiation position of the laser beam L2 (the formation position of the peripheral modification layer M1) is offset in the radial direction of the first wafer W from the formation position of the groove Wn by a distance d2 in the opposite direction.

[0102] In the present embodiment, by shifting the irradiation position of the internal laser beam L2 (the formation position of the peripheral edge reforming layer M1) by the distance d2, it is possible to suppress at least the formation of the peripheral edge reforming layer M1 in the unbonded region Ae.

[0103] However, in this case, on the side of the first wafer W facing the formation portion of the notch Wn in the circumferential direction after the formation circle of the peripheral edge modification layer M1 is shifted, as shown in FIG. Fig.11 As shown, the trimming width of the peripheral edge portion We becomes smaller than a predetermined value.

[0104] Therefore, in the present embodiment, it is desirable to shift the irradiation position of the internal laser beam L2 (the formation position of the peripheral edge modification layer M1) as described above and then further perform the above steps. Fig.12 As shown, the diameter r of the circle forming the peripheral edge reforming layer M1 is reduced so that the removal width of the peripheral edge portion We on the side facing the portion where the notch Wn is formed becomes a predetermined trimming width d1.

[0105] Then, in the control device 90 , the position where the center of the formed circle is shifted and the diameter r of the formed circle is reduced in this way is determined as the irradiation position of the inner laser beam L2 (the formation position of the peripheral edge reforming layer M1 ).

[0106] In addition, next, the bonding area Ac on the radially outer side of the determined irradiation position of the internal laser beam L2 is determined as the irradiation position of the interface laser beam L1 (the formation area of ​​the bonding force reduction area R) ( Figure 8 Step St4: Refer to Fig.12 ).

[0107] Then, in the interface modification device 50, the interface between the first wafer W and the second wafer S is irradiated with the interface laser beam L1 based on the irradiation area determined in this way, thereby forming a bonding force reduction area R ( Figure 8In step St5). In addition, in the internal reforming device 60, the internal laser beam L2 is irradiated along the irradiation position determined in this way to form the peripheral reforming layer M1 ( Figure 8 Step St7).

[0108] According to the first mode (A) of the present embodiment, the formation circle of the peripheral modified layer M1 (holding disk 100) is moved in the horizontal direction (center shift) so that the determined reference point P is at least consistent with the formation circle of the peripheral modified layer M1 or at least located radially outside the formation circle. Fig.11 As shown, it is possible to appropriately suppress the peripheral edge reforming layer M1 from being formed in the non-bonded region Ae.

[0109] Furthermore, since the diameter r of the circle forming the peripheral modified layer M1 is further reduced, the peripheral modified layer M1 can be prevented from being formed in the unbonded region Ae, and the peripheral portion We can be removed by at least the set trimming width, thereby suppressing quality degradation associated with edge trimming.

[0110] In addition, Fig.11 In the example shown, the irradiation position of the internal laser beam L2 is moved in the horizontal direction by an amount consistent with the distance d2 from the trimming width d1 to the reference point P, but as described above, sometimes an unbonded portion between the first wafer W and the second wafer S is generated at a position radially inward of the unbonded area Ae corresponding to the chamfered portion of the first wafer W.

[0111] In view of this, it is desirable to set the offset of the irradiation position of the internal laser beam L2 to be slightly larger than the distance d2 from the trimming width d1 to the reference point P. Furthermore, when the formation area of ​​the bonding strength reduction region R is predetermined, it is desirable that at least the bonding strength reduction region R is not irradiated with the internal laser beam L2.

[0112] In the above method, both the irradiation area of ​​the interface laser beam L1 (the area where the bonding force reduction area R is formed) and the irradiation position of the internal laser beam L2 (the formation position of the peripheral modified layer M1) are determined in step St4. However, the timing of determining the formation position of the peripheral modified layer M1 is not limited to this. For example, the formation position of the bonding force reduction area R may be determined by the micro camera 121 of the internal modification device 60, and the irradiation position of the internal laser beam L2 (the formation position of the peripheral modified layer M1) may be determined along the innermost periphery of the determined bonding force reduction area R.

[0113] <Second mode (B): forming an ellipse>

[0114] In the second mode (B), first, the outer end position of the first wafer W and the position of the reference point P are determined by the same method as in the first mode (A).

[0115] Next, in the second mode (B), in order to make the removal amount of the peripheral portion We of the first wafer W removed by edge trimming (the area of ​​the region radially outward than the peripheral modified layer M1) at least smaller than that of the first mode (A), the peripheral modified layer M1 is formed concentrically with the first wafer W in a manner such that at least a portion of the semicircular region on the non-formed side of the notch Wn (for example, a range of ±90 degrees in the circumferential direction based on the opposing portion with the formation position of the notch Wn) becomes a set trimming width, and the peripheral modified layer M1 is formed in an elliptical shape when viewed from above in the semicircular region on the formed side of the notch Wn in the circumferential direction of the first wafer W (for example, a range of ±90 degrees in the circumferential direction based on the notch Wn).

[0116] More specifically, first, in the circumferential direction of the first wafer W, in the half circumferential region on the non-formed side of the notch Wn (in Fig.13 In the example, the irradiation position (the formation position of the peripheral modified layer M1) of the internal laser beam L2 is set concentrically with the first wafer W at least in a part of the range from θ(90) to θ(270) in the clockwise direction with the notch Wn as the reference θ(0) ( Figure 8 At this time, considering the unbonded portion generated at the radially inner side of the unbonded area Ae, the diameter r1 of the peripheral modified layer M1 formed concentrically with the first wafer W is set to be slightly smaller than the distance r2 from the center of the first wafer W to the boundary Ad (refer to Fig.13 ).

[0117] Next, in the circumferential direction of the first wafer W, in the half circumferential region (at Fig.13 In the example, the irradiation position of the internal laser beam L2 (the formation position of the peripheral modified layer M1) is set to an elliptical shape having a short axis from the center of the first wafer W toward the formation position of the notch Wn ( Figure 8 At this time, in order to make the major axis r3 of the peripheral modified layer M1 formed into an elliptical shape coincide with the above-mentioned diameter r1, the minor axis r4 of the peripheral modified layer M1 is set to be smaller than the above-mentioned diameter r1 in consideration of the notch Wn (refer to Fig.13 ). More specifically, the irradiation position of the inner laser beam L2 is set so that the reference point P coincides with the formation position of the peripheral edge reforming layer M1 or is located radially outward of the formation position of the peripheral edge reforming layer M1.

[0118] In addition, next, the bonding area Ac on the radially outer side of the determined irradiation position of the internal laser beam L2 is determined as the irradiation position of the interface laser beam L1 (the formation area of ​​the bonding force reduction area R) ( Figure 8 Step St4: Refer to Fig.13 ).

[0119] In addition, the area for distinguishing the formation side and the non-formation side of the notch Wn is not limited to Fig.13 For example, the area on the non-forming side of the notch Wn irradiated with the internal laser beam L2 in a concentric manner with the first wafer W may be set as a fan-shaped area with a central angle greater than or less than 180 degrees, in which the internal laser beam L2 is irradiated in a concentric manner with the first wafer W.

[0120] At this time, the larger the center angle of the fan-shaped region irradiated with the inner laser beam L2 concentrically with the first wafer W, the smaller the amount of removal of the peripheral edge portion We of the first wafer W can be.

[0121] Then, in the interface modification device 50, the eccentricity between the rotation center of the holding plate 100 and the center of the first wafer W obtained based on the imaging result of the macro camera 120 in step St1 is corrected, more specifically, by eliminating Fig. 9 The holding plate 100 is moved in the horizontal direction in the manner of the sinusoidal component of the waveform shown in FIG. 1 , and while the holding plate 100 is rotated about the vertical axis, the interface between the first wafer W and the second wafer S is irradiated with the interface laser beam L1 based on the set irradiation area, thereby forming a bonding force reduction area R ( Figure 8 Step St5). In addition, in the internal reforming device 60, the Fig. 9 The holding disk 100 is moved in the horizontal direction in the manner of the sinusoidal component of the waveform shown, and the internal laser beam L2 is irradiated along the determined irradiation position, thereby forming the peripheral edge modification layer M1 ( Figure 8 Step St7).

[0122] According to the second mode (B) involved in the present embodiment, on the circumferential direction of the first wafer W, on the non-forming side of the groove Wn, the trimming width is narrowed by forming the peripheral modified layer M1 concentrically with the first wafer W, thereby achieving an improvement in the yield, and on the forming side of the groove Wn, the peripheral modified layer M1 is formed into an elliptical shape, which can suppress the edge chipping in the subsequent process.

[0123] In addition, at this time, by moving the retaining disk 100 in the horizontal direction in a manner to correct the eccentricity of the center of the first wafer W relative to the rotation center of the retaining disk 100, while forming the bonding force reduction area R and the peripheral modification layer M1, the bonding force reduction area R and the peripheral modification layer M1 can be appropriately suppressed from being formed in the unbonded area Ae.

[0124] <Third Mode (C): Avoiding the Formation of Notch Wn>

[0125] In the third mode (C), first, the outer end position of the first wafer W and the position of the reference point P are determined by the same method as in the first mode (A) to the second mode (B).

[0126] Next, in the third mode (C), in order to make the removal amount of the peripheral portion We of the first wafer W removed by edge trimming (the area of ​​the region radially outward of the peripheral modified layer M1) smaller than that of the second mode (B), the bonding force reduction region R and the peripheral modified layer M1 are formed only at the formation portion of the notch Wn in a manner avoiding the unbonded region Ae, and the peripheral modified layer M1 is formed concentrically with the first wafer W in a manner to become a set trimming width at the non-formation portion of the notch Wn.

[0127] First, at the non-forming portion of the notch Wn in the circumferential direction of the first wafer W, the irradiation position of the inner laser beam L2 (the formation position of the peripheral edge modification layer M1) concentric with the first wafer W is set with a trimming width determined in advance according to the purpose of wafer processing ( Figure 8 At this time, considering the unbonded portion generated at the radially inner side of the unbonded area Ae, the diameter r5 of the peripheral modified layer M1 formed concentrically with the first wafer W is set to be slightly smaller than the distance r6 from the center of the first wafer W to the boundary Ad (refer to Fig.14 ).

[0128] Next, the irradiation shape of the internal laser beam L2 in the plan view at the formation portion of the notch Wn is set so that the reference point P determined at the formation portion of the notch Wn in the circumferential direction of the first wafer W at least coincides with the formation position of the peripheral edge modification layer M1 or is included in the area radially outside the formation position of the peripheral edge modification layer M1. Figure 8 Specifically, in step St4 Fig.14 In the example shown, the irradiation shape of the inner laser beam L2 in a plan view is set to a substantially triangular shape along the contour of the shape (substantially triangular shape) of the notch Wn formed in the first wafer W.

[0129] In addition, next, the bonding area Ac on the radially outer side of the determined irradiation position of the internal laser beam L2 is determined as the irradiation position of the interface laser beam L1 (the formation area of ​​the bonding force reduction area R) ( Figure 8 Step St4: Refer to Fig.14 ).

[0130] The irradiation shape of the internal laser beam L2 in a plan view is not limited to Fig.14The shape that matches the outline of the notch Wn shown can be arbitrarily set as long as the reference point P at least matches the formation position of the peripheral edge reforming layer M1 or is included in the radially outer region.

[0131] Specifically, for example, Fig.15 As shown in FIG. 1 , the irradiation shape of the internal laser beam L2 is set to a substantially elliptical shape at the portion where the notch Wn is formed. Alternatively, Fig.16 As shown in FIG. 1 , the first wafer W is set to be curved inwardly in the radial direction of the first wafer W, and can also be set as shown in FIG. Fig.17 As shown in FIG. 1 , the first wafer W is set to have an arc shape that curves outward in the radial direction of the first wafer W.

[0132] And, for example, Fig.18 As shown in FIG. 1 , the irradiation shape of the internal laser beam L2 is set to a straight line (so-called directional flat shape) at the portion where the notch Wn is formed. Alternatively, Fig.19 Alternatively, it can be set as a rectangular shape. Fig. 20 As shown in FIG. 1 , the irradiation shape of the internal laser beam L2 is set to a trapezoidal shape having an oblique side with respect to the irradiation direction from the center of the first wafer W. In addition, the irradiation direction from the center of the first wafer W is the same direction as the formation direction of the divided reformed layer M2 formed in the internal reforming device 60.

[0133] Then, in the interface modification device 50, the eccentricity between the rotation center of the holding plate 100 and the center of the first wafer W obtained based on the imaging result of the macro camera 120 in step St1 is corrected, more specifically, by eliminating Fig. 9 The holding plate 100 is moved in the horizontal direction in the manner of the sinusoidal component of the waveform shown, and the interface between the first wafer W and the second wafer S is irradiated with the interface laser beam L1 based on the set irradiation area, thereby forming a bonding force reduction area R ( Figure 8 Step St5). In addition, in the internal reforming device 60, the Fig. 9 The holding plate 100 is moved in the horizontal direction in the manner of the sinusoidal component of the waveform shown, and the first wafer W is irradiated with the internal laser beam L2 along the set irradiation shape, thereby forming a peripheral modified layer M1 ( Figure 8 Step St7). The method of correcting the eccentricity between the rotation center of the holding plate 100 and the center of the first wafer W is the same as that of the second mode (B).

[0134] Here, the formation of the peripheral modification layer M1 concentrically with the first wafer W on the non-forming portion of the notch Wn and the formation of the peripheral modification layer M1 of the above-mentioned shapes on the forming portion of the notch Wn can be performed continuously through the so-called one-time processing method or can be performed separately in two times.

[0135] (When the peripheral modified layer M1 is continuously formed)

[0136] In the case where the formation of the peripheral edge modification layer M1 for the non-formed portion of the notch Wn and the formation of the peripheral edge modification layer M1 for the formed portion are performed continuously, for example, Fig.21 As shown, for the waveform generated to correct the eccentricity between the rotation center of the holding plate 100 and the center of the first wafer W (see Fig. 9 ), the irradiation shape of the laser beam L2 is irradiated inside the formed portion of the set notch Wn (in Fig.21 The example shown is Fig.15 The corresponding elliptical shape) is overlapped with the circumferential position (angle) of the notch Wn to generate Fig.21 Then, the peripheral edge reforming layer M1 is formed inside the first wafer W using the synthesized waveform generated in this way.

[0137] Specifically, at the non-formed portion of the groove Wn, the retaining disk 100 is rotated around the vertical axis and the retaining disk 100 is moved in the horizontal direction (correcting the eccentricity) in a manner to offset the sinusoidal curve component of the synthetic waveform (the eccentricity between the rotation center of the retaining disk 100 and the center of the first wafer W), and the interior is irradiated with the laser beam L2 in a concentric circle with the first wafer W.

[0138] In addition, at the portion where the notch Wn is formed, the internal laser beam L2 is irradiated while the retaining plate 100 and the laser head 110 are relatively moved in the horizontal direction so as to avoid the unjoined area Ae at the portion where the notch Wn is formed, more specifically, so as to locate the determined reference point P at a position radially outward of the irradiation position of the internal laser beam L2. At this time, the retaining plate 100 may be rotated about the vertical axis in accordance with the irradiation shape of the internal laser beam L2, or the retaining plate 100 may be stopped.

[0139] The same also applies to the formation of the joining force reduction region R. That is, as described above, the joining force reduction region R may be continuously formed without interruption at the forming portion and the non-forming portion of the notch Wn.

[0140] (When the peripheral modified layer M1 is formed twice)

[0141] On the other hand, when the formation of the peripheral modified layer M1 on the non-formed portion of the notch Wn and the formation of the peripheral modified layer M1 on the formed portion are performed twice, first, a composite waveform obtained by overlapping the irradiation shapes of the internal laser beam L2 determined in the same manner as in the case of continuously forming the peripheral modified layer M1 is generated (see Fig.21 ).

[0142] Next, for the non-formed portion of the groove Wn, the retaining disk 100 is rotated around the vertical axis while being moved in the horizontal direction (correcting the eccentricity) in a manner to offset the sinusoidal component of the synthetic waveform (the eccentricity between the rotation center of the retaining disk 100 and the center of the first wafer W), and the inside is irradiated with the laser beam L2 in a concentric circle with the first wafer W.

[0143] When the peripheral edge modification layer M1 is formed in the non-forming portion of the notch Wn, the retaining plate 100 is then moved to a position for forming the peripheral edge modification layer M1 in the forming portion of the notch Wn. Fig. 22 , Fig.23 As shown, as an example, the irradiation shape of the internal laser beam L2 for generating the synthetic waveform can be generated by overlapping a circular shape or an elliptical shape having a rotation axis different from the rotation axis of the first wafer W. From this point of view, when the peripheral edge modification layer M1 is formed at the portion where the notch Wn is formed, the holding plate 100 (first wafer W) is moved so that the rotation center of the holding plate 100 coincides with the rotation axis of the circular shape or the elliptical shape overlapped to generate the synthetic waveform in this way, and the internal laser beam L2 is irradiated to the inside of the first wafer W while the holding plate 100 is rotated around the vertical axis at a position for forming the peripheral edge modification layer M1 at the portion where the notch Wn is formed.

[0144] In addition, when the notch Wn is formed at the portion such as Fig.18 , Fig.19 In the case where the peripheral modified layer M1 is formed in a rectangular shape, the irradiation shape of the internal laser beam L2 does not have the same Fig. 22 , Fig.23 The rotation axis as shown.

[0145] In this case, the interior of the first wafer W may be irradiated with the internal laser beam L2 only while the holding plate 100 and the laser head 110 are relatively moved in the horizontal direction. There is no need to move the holding plate 100 to a position for forming the peripheral modification layer M1 at the portion where the notch Wn is to be formed.

[0146] The same also applies to the formation of the joining force reduction region R. That is, the joining force reduction region R may be formed by performing processing twice on the forming portion and the non-forming portion of the notch Wn as described above.

[0147] According to the third mode (C) above, in the circumferential direction of the first wafer W, the bonding force reduction region R and the peripheral edge modification layer M1 are formed concentrically with the first wafer W at the non-formed portion of the notch Wn, and the bonding force reduction region R and the peripheral edge modification layer M1 are formed only at the formed portion of the notch Wn in a manner avoiding the non-bonded region Ae. Thus, compared with the second mode (B) above, the removal amount of the peripheral portion We can be further reduced, and the yield rate can be improved.

[0148] Furthermore, as described above, in the first mode (A) to the third mode (C), information about the unbonded portion (the formation position of the unbonded portion where the first wafer W and the second wafer S are not bonded) including the formation position of the unbonded region Ae in the peripheral portion We (more specifically, the position of the boundary Ad) can be obtained, for example, based on the image pickup result of the camera, or, for example, it can be set to output information obtained in advance outside the wafer processing system 1 to the control device 90 while the overlapped wafer T (front-opening FOUP F) is carried into the wafer processing system 1. The information about the unbonded portion can be obtained, for example, by a bonding device (not shown) that bonds the first wafer W and the second wafer S.

[0149] In addition, in the above embodiment, as described above, the information of the unbonded portion is obtained based on the image pickup result of the camera of the internal modification device 60, but the camera may be arranged in other devices arranged in the wafer processing system 1 to obtain the information by taking an image. As the arrangement of the camera for taking an image of the first wafer W, for example, the conveyor device 30 may be considered.

[0150] In addition, in the above-mentioned first mode (A) to third mode (C), the position of the boundary Ad between the unbonded area Ae and the bonded area Ac obtained based on the camera's imaging results is used as the above-mentioned "information on the unbonded portion", but as mentioned above, the unbonded portion of the first wafer W and the second wafer S may also be generated at a position radially inward of the boundary Ad.

[0151] In view of this point of view, it is desirable that the “information of the unbonded portion” acquired before forming the peripheral modified layer M1 includes the position of the unbonded portion located most radially inward in the interface between the first wafer W and the second wafer S at the formation portion of the notch Wn. In this case, the unbonded portion located most radially inward in the interface between the first wafer W and the second wafer S becomes the “reference point P”.

[0152] In addition, in the above-mentioned embodiment, the bonding force reduction region R and the peripheral modified layer M1 are formed at a position slightly radially inward of the boundary Ad acquired as the “information of the unbonded portion”, so that the unbonded portion generated at a position radially inward of the boundary Ad is included in the trimming width based on the edge trimming. However, by acquiring the position of the unbonded portion located at the most radially inward position in the interface between the first wafer W and the second wafer S at the formation portion of the notch Wn as the “information of the unbonded portion”, it is possible to more appropriately suppress the unbonded portion from remaining at the interface between the first wafer W and the second wafer S after the edge trimming.

[0153] In addition, when the peripheral modified layer M1 is formed in a manner avoiding the notch Wn as in the third mode (C) described above, a corner K is formed at the outer end of the first wafer W after removing the peripheral portion We (see Fig.24 In the case of (a), the corner portion K may be chipped in a subsequent step and may cause edge chipping.

[0154] Therefore, when the peripheral edge modification layer M1 is formed in a manner avoiding the notch Wn, it is desirable to correct the irradiation shape of the internal laser beam L2 so that the corner K is not formed at the outer end of the first wafer W after the peripheral edge We is removed. Fig.24 The synthetic waveform shown as an example in (a) is averaged, as shown in FIG. Fig.24 As shown in (b), the contour of the outer end of the first wafer W after the peripheral edge portion We is removed becomes smooth, and edge chipping in subsequent steps can be suppressed.

[0155] In addition, in the wafer processing system 1 involved in the technology disclosed in the present invention, Fig.25 As shown, the first wafer W having the peripheral modified layer M1 formed thereon has the first crystal orientation CO1 and the second crystal orientation CO2 alternately in the circumferential direction of the first wafer W. The notches Wn formed in the first wafer W are notches for indicating the crystal orientations.

[0156] Therefore, in order to properly extend the crack C along the crystal orientation from the peripheral modified layer M1 formed on the first wafer W through the internal modification device 60, it is necessary to consider the crystal orientation to determine the irradiation conditions such as the incident direction of the internal laser beam L2, the focal point shape of the internal laser beam L2 (the direction of the long side direction of the focal point), etc.

[0157] Specifically, when the peripheral modified layer M1 is formed concentrically with the first wafer W, according to Fig.25 The irradiation conditions of the internal laser beam L2 are changed according to the crystal orientation shown (the first crystal orientation CO1 or the second crystal orientation CO2).

[0158] On the other hand, when the peripheral modified layer M1 is formed in a manner avoiding the notch Wn as in the third mode (C) described above, the relative irradiation angle of the internal laser beam L2 with respect to the crystal orientation of the first wafer W changes according to the irradiation shape of the internal laser beam L2 when viewed from above (the irradiation position of the internal laser beam L2). Therefore, in addition to considering the formation portion of the notch Wn, Fig.25 In addition to the crystal orientation (first crystal orientation CO1 or second crystal orientation CO2) shown, the irradiation conditions of the internal laser beam L2 are changed in consideration of the trimmed shape of the peripheral portion We (the irradiation shape of the internal laser beam L2 in a plan view).

[0159] The information on the crystal orientation of the first wafer W may be acquired, for example, at the same time when the stacked wafers T (front-opening FOUP F) are loaded into the wafer processing system 1 or before that.

[0160] In addition, in the above description, Figure 7 As shown in the figure, after the bonding force reduction region R is formed by the interface modification device 50, the peripheral modification layer M1 and the split modification layer M2 are formed by the internal modification device 60, but the order of substrate processing in the wafer processing system 1 is not limited to this. That is, the bonding force reduction region R may be formed by the interface modification device 50 after the peripheral modification layer M1 and the split modification layer M2 are formed by the internal modification device 60.

[0161] In this case, as described above, the irradiation region of the interface laser beam L1 for forming the joining strength reduced region R (the formation region of the joining strength reduced region R) may be set based on the position of the peripheral reformed layer M1 formed by the internal reforming device 60 .

[0162] In addition, in the above-mentioned embodiment, the case where the unbonded area Ae is formed in the overlapping wafer T formed by bonding the first wafer W and the second wafer S is described, but the unbonded area Ae can also be formed in the first wafer W or the second wafer S before the first wafer W and the second wafer S are bonded, and then the first wafer W and the second wafer S are bonded to form an overlapping wafer.

[0163] In this case, as a method of forming the unbonded region Ae, a process using laser light or a process using etching such as wet etching may be used.

[0164] In addition, in the above embodiment, when an unbonded area Ae is formed in the first wafer W and is closer to the inner periphery of the wafer than the unbonded area at the notch Wn, the formation position of the peripheral modified layer M1 can also be determined based on the information of the above-mentioned unbonded portion corresponding to the innermost unbonded area Ae.

[0165] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The above embodiments may be omitted, replaced, or changed in various ways without departing from the attached claims and their subject matter. For example, the constituent elements of the above embodiments may be combined arbitrarily. According to the arbitrary combination, the functions and effects of each constituent element related to the combination can be obtained, and other functions and effects that are obvious to those skilled in the art based on the description of this specification can be obtained.

[0166] In addition, the effects described in this specification are merely explanatory or illustrative effects and are not limited thereto. That is, the technology involved in the present disclosure can have other effects that are obvious to those skilled in the art based on the description of this specification in addition to or in place of the above effects.

[0167] Description of Reference Numerals

[0168] 1: wafer processing system; 60: internal modification device; 70: peripheral removal device; 90: control device; Ac: bonding area; Ae: unbonded area; L2: internal laser beam; M1: peripheral modification layer; S: second wafer; T: overlapping wafer; W: first wafer; Wc: central part; We: peripheral part; Wn: notch.

Claims

1. A substrate processing method for processing an overlapping substrate formed by bonding a first substrate and a second substrate, wherein: The first substrate has: a notch formed by cutting away a portion of a peripheral edge portion of the first substrate to be removed; a bonding portion bonded to the second substrate; as well as an unbonded portion not bonded to the second substrate, The substrate processing method comprises: irradiating a laser beam along a boundary between the peripheral portion of the first substrate and a central portion of the first substrate to form a peripheral reforming layer that becomes a base point for peeling of the peripheral portion; and The peripheral portion is peeled off from the stacked substrate with the peripheral modified layer as a starting point, When forming the peripheral edge modification layer, a formation position of the peripheral edge modification layer corresponding to the formation portion of the notch is determined based on information of the non-bonded portion.

2. The substrate processing method according to claim 1, wherein: The information of the unbonded portion includes the position of a reference point of the unbonded portion, which is located most inner in the radial direction of the first substrate at the portion where the notch is formed. The center position of the formation circle of the peripheral edge reforming layer formed in a circular shape in a plan view is shifted so that the reference point is located at least outside the formation circle.

3. The substrate processing method according to claim 2, wherein: The diameter of the formation circle is reduced based on a predetermined removal width of the peripheral edge portion at a counter position of the notch formation portion.

4. The substrate processing method according to claim 1, comprising: The peripheral edge modification layer is formed at least partially in a semicircular region of the first substrate on a side where the notch is not formed, so as to be concentric with the first substrate in a plan view; and The peripheral edge reforming layer is formed in at least a portion of a semicircumferential region on the notch forming side of the first substrate into an elliptical shape having a minor axis from the center of the first substrate toward the notch forming position in a plan view.

5. The substrate processing method according to claim 4, wherein: The information of the unbonded portion includes the position of a reference point of the unbonded portion, which is located most inner in the radial direction of the first substrate at the portion where the notch is formed. The major axis of the ellipse is set to the same length as the diameter of the concentric circle in the semicircular region on the non-forming side of the notch, The minor axis of the elliptical shape is set to be shorter than the distance from the center of the first substrate to the reference point.

6. The substrate processing method according to claim 1, wherein: The information of the unbonded portion includes the position of a reference point of the unbonded portion, which is located most inner in the radial direction of the first substrate at the portion where the notch is formed. The substrate processing method comprises: At a portion of the first substrate in the circumferential direction where the notch is not formed, the peripheral edge modification layer is formed to be concentric with the first substrate in a plan view; and At a portion of the first substrate where the notch is formed in the circumferential direction, the peripheral edge reforming layer is formed in a shape along the non-bonded portion formed corresponding to the notch in a plan view.

7. The substrate processing method according to claim 6, wherein: The peripheral edge modification layer at the notch non-formation portion is formed continuously with the peripheral edge modification layer at the notch formation portion.

8. The substrate processing method according to claim 6, wherein: The peripheral edge modification layer at the notch non-formation portion and the peripheral edge modification layer at the notch formation portion are formed separately and twice.

9. The substrate processing method according to any one of claims 6 to 8, comprising: Generate a composite waveform representing a formation position of the peripheral edge modification layer for the first substrate by overlapping a waveform representing a correlation of an eccentricity between a center of the first substrate and a rotation center of a substrate holding portion holding the superimposed substrate with respect to a circumferential direction of the first substrate with a formation shape of the peripheral edge modification layer when viewed from above with respect to a formation portion of the notch; and The determined synthesized waveform is subjected to averaging processing.

10. The substrate processing method according to any one of claims 6 to 8, wherein: The substrate processing method includes determining irradiation conditions for irradiating the first substrate with the laser beam in consideration of the crystal orientation of the first substrate and a formed shape of the peripheral edge reforming layer in a plan view of a portion where the notch is formed.

11. The substrate processing method according to any one of claims 1 to 8, wherein: The substrate processing method includes: irradiating a second laser beam to an interface between the first substrate and the second substrate to form a bonding force reduction region where a bonding force between the first substrate and the second substrate is reduced, In the substrate processing method, the formation position of the bonding force reduction region corresponding to the formation portion of the notch is determined based on the information of the non-bonded portion.

12. The substrate processing method according to any one of claims 1 to 8, wherein: The substrate processing method includes acquiring information on the non-bonded portion by imaging the overlapping substrates held by a substrate holding portion.

13. A substrate processing system for processing a stacked substrate formed by bonding a first substrate and a second substrate, wherein: The first substrate has: a notch formed by cutting away a portion of a peripheral edge portion of the first substrate to be removed; a bonding portion bonded to the second substrate; as well as an unbonded portion not bonded to the second substrate, The substrate processing system comprises: an internal reforming device for irradiating a laser beam along a boundary between the peripheral portion of the first substrate and a central portion of the first substrate to form a peripheral reforming layer that becomes a base point for peeling of the peripheral portion; a peripheral edge removal device for peeling the peripheral edge portion from the stacked substrates based on the peripheral edge modification layer; and Control device, When forming the peripheral edge modification layer, the control device performs the following control: based on the information of the non-bonded portion, a formation position of the peripheral edge modification layer corresponding to the formation portion of the notch is determined.

14. The substrate processing system according to claim 13, wherein: The internal reforming device comprises: a substrate holding portion that holds the stacked substrates; a laser irradiation section that irradiates the laser beam; and a camera that captures the stacked substrates held by the substrate holding portion, The control device controls the operation of the internal reforming device so as to acquire information on the unbonded portion by photographing the overlapping substrates held by the substrate holding portion.

15. The substrate processing system according to claim 13, wherein: The invention further comprises an interface modification device, wherein the interface modification device irradiates a second laser beam to the interface between the first substrate and the second substrate to form a bonding force reduction region where the bonding force between the first substrate and the second substrate is reduced. When forming the joining force reduction region, the control device performs control to determine a formation position of the joining force reduction region corresponding to a formation portion of the notch based on information on the non-joined portion.

16. The substrate processing system according to any one of claims 13 to 15, wherein: The information of the unbonded portion includes the position of a reference point of the unbonded portion, which is located most inner in the radial direction of the first substrate at the portion where the notch is formed. When forming the peripheral edge modification layer, the control device performs control to shift the center position of a formation circle of the peripheral edge modification layer formed in a circular shape in a plan view so that the reference point is located at least outside the formation circle.

17. The substrate processing system according to any one of claims 13 to 15, wherein: When forming the peripheral edge modification layer, the control device performs the following control: The peripheral edge modification layer is formed at least partially in a semicircular region of the first substrate on a side where the notch is not formed, so as to be concentric with the first substrate in a plan view; and The peripheral edge reforming layer is formed in at least a portion of a semicircumferential region on the notch forming side of the first substrate into an elliptical shape having a minor axis from the center of the first substrate toward the notch forming position in a plan view.

18. The substrate processing system according to any one of claims 13 to 15, wherein: The information of the unbonded portion includes the position of a reference point of the unbonded portion, which is located most inner in the radial direction of the first substrate at the portion where the notch is formed. When forming the peripheral edge modification layer, the control device performs the following control: At a portion of the first substrate in the circumferential direction where the notch is not formed, the peripheral edge modification layer is formed to be concentric with the first substrate in a plan view; and At a portion of the first substrate where the notch is formed in the circumferential direction, the peripheral edge reforming layer is formed in a shape along the non-bonded portion formed corresponding to the notch in a plan view.

Images