Substrate processing system, substrate processing method, and computer storage medium

Abstract

Provided is a substrate processing system for processing a substrate, the substrate processing system comprising: a laser irradiation unit for irradiating the substrate with laser light from above the substrate; an image acquisition unit for acquiring a projection image of the substrate from a side of the substrate; and a control unit. The control unit executes: the control for acquiring the projection image by the image acquisition unit before the irradiation of the substrate with the laser light at the laser irradiation unit; and the control for determining at least one of the irradiation position of the laser light and the output of the laser light on the substrate on the basis of the projection image obtained before the irradiation with the laser light.

Description

SUBSTRATE PROCESSING SYSTEM, SUBSTRATE PROCESSING METHOD, AND COMPUTER STORAGE MEDIUM

[0001] The present disclosure relates to a substrate processing system, a substrate processing method, and a computer storage medium.

[0002] Each of Patent Documents 1 to 3 discloses a substrate processing system for processing a laminated substrate formed by bonding a first substrate and a second substrate. The substrate processing system includes a modified layer forming device that forms a modified layer inside the first substrate, and a peripheral edge removing device that removes the peripheral edge of the first substrate.

[0003] International Publication No. 2019 / 176589 International Publication No. 2019 / 208298 International Publication No. 2019 / 208359 International Publication No. 2020 / 105483 International Publication No. 2023 / 079956 International Publication No. 2023 / 157566

[0004] The technology according to the present disclosure appropriately performs laser processing on a substrate.

[0005] One aspect of the present disclosure is a substrate processing system for processing a substrate, comprising: a laser irradiation unit that irradiates the substrate with laser light from above the substrate; an image acquisition unit that acquires a projected image of the substrate from the side of the substrate; and a control unit, wherein the control unit performs control to acquire the projected image with the image acquisition unit before the laser irradiation unit irradiates the substrate with the laser light, and control to determine at least one of the irradiation position of the laser light on the substrate or the output of the laser light based on the projected image before the laser light is irradiated.

[0006] According to the present disclosure, laser processing of a substrate can be performed appropriately.

[0007] 1 is an explanatory diagram of overlapping wafers to be processed; FIG. 2 is a plan view showing the outline of the configuration of a wafer processing system; FIG. 3 is a side view showing the outline of the configuration of a peripheral edge removal device; FIG. 4 is a plan view showing the outline of the configuration of a peripheral edge removal device; FIG. 5 is an explanatory diagram showing an example of a projected image; FIG. 6 is a side view showing the outline of the configuration of a first laser irradiation device (second laser irradiation device, third laser irradiation device); FIG. 7 is a plan view showing the outline of the configuration of a first laser irradiation device (second laser irradiation device, third laser irradiation device); FIG. 8 is a side view showing the outline of the configuration of a peripheral edge removal device; FIG. 9 is a plan view showing the outline of the configuration of a peripheral edge removal device; FIG. 10 is a flow diagram showing main steps of wafer processing; FIG. 11 is an explanatory diagram showing main steps of wafer processing; FIG. 12 is an explanatory diagram showing how the height position and insertion amount of an insertion blade are determined; FIG. 13 is an explanatory diagram showing a removal portion where the peripheral edge portion has been removed on the first wafer; FIG. 14 is an explanatory diagram showing how the height position and insertion amount of a cutting blade according to another embodiment are determined; FIG. 15 is an explanatory diagram showing how a back surface film on the back surface of a first wafer is removed according to another embodiment; FIG. 16 is an explanatory diagram showing main steps of wafer processing according to another embodiment; and FIG. 17 is a flow diagram showing main steps of wafer processing according to another embodiment.

[0008] In the manufacturing process of semiconductor devices, a first wafer, which is a semiconductor substrate (hereinafter referred to as a "wafer") having a plurality of devices such as electronic circuits formed on its surface, is bonded to a second wafer to form a laminated wafer, and the first wafer is thinned. Before the thinning process of the first wafer, a process called edge trimming is performed to remove the peripheral portion of the first wafer.

[0009] Edge trimming of the first wafer is performed, for example, in a substrate processing system disclosed in Patent Documents 1 to 3. In the substrate processing system, a modified layer forming device irradiates the first wafer with laser light along the boundary between the peripheral portion and central portion of the first wafer to be removed, thereby forming a modified layer inside the first wafer. At this time, the irradiation position of the laser light on the first wafer and the output power of the laser light are determined by measuring the position of the first wafer from above or to the side using a laser displacement meter, as disclosed in Patent Documents 4 to 6, for example. Then, a peripheral edge removal device removes the peripheral portion of the first wafer, starting from the modified layer.

[0010] Here, the peripheral edge of the first wafer is chamfered, and the cross-section of the peripheral edge becomes thinner toward its tip. Furthermore, in three-dimensional integration technology for stacking semiconductor devices in three dimensions, the first wafer undergoes repeated desired processing, causing the surface shape of the chamfered peripheral edge to change over time. Specifically, for example, irregularities may occur on the surface of the peripheral edge, or the slope of the surface of the peripheral edge may change. If the surface of the peripheral edge is uneven or sloped, there is a concern that accurate measurement may not be possible when measuring the position of the first wafer from above, as in the conventional method, and there is room for improvement.

[0011] If the surface shape of the first wafer changes over time in this way, when the first wafer is irradiated with laser light under the conditions determined as described above, the irradiation energy of the laser light may not be properly transmitted to the first wafer, resulting in processing defects. Therefore, there is room for improvement in conventional laser processing.

[0012] The technology disclosed herein appropriately performs laser processing on a substrate. Hereinafter, a wafer processing system as a substrate processing system and a wafer processing method as a substrate processing method according to an embodiment of the present invention will be described with reference to the drawings. Note that in this specification and the drawings, elements having substantially the same functional configurations are designated by the same reference numerals, and redundant description will be omitted.

[0013] 1 , a wafer processing system 1 according to this embodiment, which will be described later, processes an overlapped wafer T as an overlapped substrate in which a first wafer W as a first substrate and a second wafer S as a second substrate are bonded together. 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.

[0014] The first wafer W is a semiconductor wafer such as a silicon substrate, and at least one film is laminated on the front surface Wa side. Hereinafter, the film formed on the front surface Wa side will be referred to as a "laminated film." In this embodiment, the laminated film includes a device layer Dw and a bonding film Fw. The device layer Dw includes a plurality of devices. The bonding film Fw may include, for example, an oxide film (THOX film, SiO ２ The first wafer W is bonded to the second wafer S via a bonding film Fw. The peripheral edge We of the first wafer W is chamfered, and the thickness of the cross section of the peripheral edge We decreases toward its tip. In the following description, the region of the first wafer W radially inward from the peripheral edge We to be removed may be referred to as the central region Wc.

[0015] The second wafer S has, for example, the same configuration as the first wafer W. That is, a device layer Ds and a bonding film Fs are formed as laminated films on the surface Sa side, and the peripheral portion 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.

[0016] 1 illustrates an example in which a device layer and a bonding film are formed as laminated films on the surfaces of the first wafer W and the second wafer S. However, the type and number of laminated films are not limited to this.

[0017] 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 FOUP F 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.

[0018] The carry-in / out station 2 is provided with a FOUP mounting table 10 on which a plurality of FOUPs F are placed. A wafer transfer device 20 is provided adjacent to the FOUP mounting table 10 on the positive X-axis side of the FOUP 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 overlapped wafers T between the FOUPs F on the FOUP mounting table 10 and a transition device 30, which will be described later.

[0019] In the loading / unloading station 2 , a transition device 30 for transferring the overlapped wafer T between the processing station 3 and the wafer transfer device 20 is provided adjacent to the wafer transfer device 20 on the positive side of the X axis of the wafer transfer device 20 .

[0020] In the processing station 3, a wafer transfer device 40, an edge removal device 50, a cleaning device 60, a first laser irradiation device 70, a second laser irradiation device 80, a third laser irradiation device 90, and an inspection device 100 are arranged. The wafer transfer device 40 is arranged on the X-axis positive side of the transition device 30. The edge removal device 50, the first laser irradiation device 70, and the third laser irradiation device 90 are arranged on the Y-axis positive side of the wafer transfer device 40, and the cleaning device 60, the second laser irradiation device 80, and the inspection device 100 are arranged on the Y-axis negative side of the wafer transfer device 40. Note that the number and arrangement of the edge removal device 50, the cleaning device 60, the first laser irradiation device 70, the second laser irradiation device 80, the third laser irradiation device 90, and the inspection device 100 are not limited to those in this embodiment and can be determined arbitrarily.

[0021] The wafer transport device 40 is configured to be freely movable on a transport path 41 extending in the X-axis direction, and is configured to be able to transport the overlapped wafer T to the transition device 30, edge removal device 50, cleaning device 60, first laser irradiation device 70, second laser irradiation device 80, third laser irradiation device 90 and inspection device 100.

[0022] The edge removal device 50 removes the edge portion We of the first wafer W, i.e., performs edge trimming, using the edge modification region N, described below, formed by the first laser irradiation device 70 and the bonding strength reduction region R, described below, formed by the second laser irradiation device 80 as base points.

[0023] 3 and 4, the edge removal apparatus 50 has a chuck 110 as a substrate holder that holds the overlapped wafer T on its upper surface. The chuck 110 suction-holds the back surface Sb of the second wafer S in a state in which the first wafer W is placed on top and the second wafer S is placed on the bottom. The chuck 110 is supported by a rotation mechanism 111. The rotation mechanism 111 incorporates, for example, a motor as a drive source. The chuck 110 is configured to be rotatable about a vertical axis by the rotation mechanism 111.

[0024] An insertion blade 120 serving as an insertion member is provided on the side of the chuck 110 in the positive direction of the X-axis. The insertion blade 120 has, for example, a wedge shape. The insertion blade 120 is attached to a movement mechanism 121 that allows the insertion blade 120 to move freely in the horizontal and vertical directions. The insertion blade 120 is inserted between the first wafer W and the second wafer S. In this embodiment, the insertion blade 120 and the movement mechanism 121 constitute a peripheral edge removal unit.

[0025] An image acquisition unit 130 is provided on the side of the chuck 110, on the negative side of the Y axis. The image acquisition unit 130 has a light-projecting unit 131 and a light-receiving unit 132. The light-projecting unit 131 and the light-receiving unit 132 are arranged so that an optical axis A passes through the peripheral portion of the overlapped wafer T (the peripheral portion We of the first wafer W). The image acquisition unit 130 irradiates light from the light-projecting unit 131 toward the light-receiving unit 132, and acquires a projection image P including the peripheral portion of the overlapped wafer T, as shown in FIG. 5, for example. The projection image P acquired by the image acquisition unit 130 is output to a control device 200, which will be described later.

[0026] The cleaning device 60 cleans the first wafer W and the second wafer S after the edge trimming by the edge removal device 50, and removes particles from these wafers. Any cleaning method can be selected.

[0027] The first laser irradiation device 70 irradiates the inside of the first wafer W with a first laser beam (modifying laser beam, for example, a fiber laser or a YAG laser) to form a peripheral modified layer M (see FIG. 11 described later) and a peripheral modified region N (see FIG. 11 described later) that serves as a base point for peeling off the peripheral portion We. The first laser irradiation device 70 also has a control device 71 described later.

[0028] As shown in FIGS. 6 and 7 , the first laser irradiation device 70 includes a chuck 140 as a substrate holder that holds the overlapped wafer T on its upper surface. The chuck 140 suction-holds the back surface Sb of the second wafer S with the first wafer W on top and the second wafer S on the bottom. The chuck 140 is supported by a slider table 142 via an air bearing 141. A rotation mechanism 143 is provided on the underside of the slider table 142. The rotation mechanism 143 incorporates, for example, a motor as a drive source. The chuck 140 is configured to be rotatable about a vertical axis by the rotation mechanism 143 via the air bearing 141. The slider table 142 is configured to be movable along rails 146 extending in the Y-axis direction on a base 145 via a movement mechanism 144 provided on its underside. The drive source of the movement mechanism 144 is not particularly limited, but may be, for example, a linear motor.

[0029] A laser irradiation unit 150 is provided above the chuck 140. The laser irradiation unit 150 includes a laser head 151, an optical system 152, and a lens 153.

[0030] The laser head 151 has a laser oscillator (not shown) that oscillates a first laser beam in a pulsed manner. This first laser beam is a so-called pulse laser. As described above, the first laser beam is, for example, a fiber laser beam or a YAG laser beam. Note that the laser head 151 may also have other devices in addition to the laser oscillator, such as an amplifier.

[0031] The optical system 152 may include an optical element (not shown) that controls the intensity and position of the first laser beam, and an attenuator (not shown) that attenuates the first laser beam to adjust the output. The optical system 152 may also be configured to be able to control the number and shape of the branches of the first laser beam.

[0032] The lens 153 irradiates the first laser light onto the inside of the first wafer W held by the chuck 140. As a result, the portion inside the overlapped wafer T that has been irradiated with the first laser light is modified, and a peripheral modified layer M (see FIG. 11 described later) is formed.

[0033] An image acquisition unit 160 is provided to the side of the chuck 140, on the negative Y-axis direction side of the lens 153. The image acquisition unit 160 has a configuration similar to that of the image acquisition unit 130 described above, and includes a light-projecting unit 161 and a light-receiving unit 162. The light-projecting unit 161 and the light-receiving unit 162 are arranged so that an optical axis A passes through the peripheral portion of the overlapped wafer T (the peripheral portion We of the first wafer W). The image acquisition unit 160 irradiates light from the light-projecting unit 161 toward the light-receiving unit 162, and acquires a projection image P including the peripheral portion of the overlapped wafer T, as shown in FIG. 5, for example. The projection image P acquired by the image acquisition unit 160 is output to a control device 71 or a control device 200, which will be described later.

[0034] An imaging unit 170 is provided above the chuck 140 on the positive Y-axis side of the lens 153. The imaging unit 170 includes at least one camera. An image captured by the camera is output to a control device 71 or a control device 200, which will be described later. The first laser irradiation device 70 determines the position of the overlapped wafer T on the chuck 140 based on the image obtained by the imaging unit 170, and aligns the overlapped wafer T based on this.

[0035] The second laser irradiation device 80 applies a second laser beam (interface laser beam, for example, CO ２ 2, the second laser irradiation device 80 irradiates the first wafer W with a laser beam (laser) to form a bonding strength reduced region R (see FIG. 11 described later) in which the bonding strength between the first wafer W and the second wafer S is reduced in the peripheral edge portion We. As shown in FIG. 2, the second laser irradiation device 80 also has a control device 81 described later.

[0036] 6 and 7, the second laser irradiation device 80 has a configuration similar to that of the first laser irradiation device 70. In the second laser irradiation device 80, the projected image P acquired by the image acquisition unit 160 and the image captured by the image capturing unit 170 are output to a control device 81 or a control device 200, which will be described later. The lens 153 irradiates the inside of the overlapped wafer T held by the chuck 140, more specifically, the interface between the first wafer W and the second wafer S, with a second laser beam. The second laser beam is a pulsed laser, and may be, for example, a CO ２ The second laser beam is a laser. This modifies the portion inside the overlapped wafer T that is irradiated with the second laser beam, forming a bonding strength reduced region R (see FIG. 11 described later) in which the bonding strength between the first wafer W and the second wafer S is reduced. In the technology according to the present disclosure, the "interface between the first wafer W and the second wafer S" includes the respective interfaces and interiors of the first wafer W, the device layers Dw, Ds, the bonding films Fw, Fs, and the second wafer S. In other words, as long as the bonding strength between the first wafer W and the second wafer S can be reduced, the position where the bonding strength reduced region R is formed is not particularly limited.

[0037] The third laser irradiation device 90 irradiates an irradiation target with third laser light (removal laser light, for example, a UV femtosecond laser) and removes the irradiation target by laser ablation. As will be described later, the irradiation target is, for example, a surface film (bonding films Fw, Fs and device layers Dw, Ds) on the surface Sa of the second wafer S. As shown in FIG. 2 , the third laser irradiation device 90 also has a control device 91, which will be described later.

[0038] 6 and 7 , the third laser irradiation device 90 has a configuration similar to that of the first laser irradiation device 70. In the third laser irradiation device 90, the projected image P acquired by the image acquisition unit 160 and the image captured by the imaging unit 170 are output to a control device 91 or a control device 200, which will be described later. The lens 153 irradiates the third laser light onto the irradiation target, which is the laminated wafer T held by the chuck 140. The third laser light is a pulsed laser, such as a UV femtosecond laser.

[0039] 2, the inspection apparatus 100 inspects the state of the overlapped wafer T. The inspection apparatus 100 also includes a control apparatus 101, which will be described later.

[0040] 8 and 9, the inspection device 100 has a chuck 180 as a substrate holder that holds the overlapped wafer T on its upper surface. The chuck 180 suction-holds the back surface Sb of the second wafer S in a state in which the first wafer W is placed on top and the second wafer S is placed on the bottom. The chuck 180 is supported by a rotation mechanism 181. The rotation mechanism 181 incorporates, for example, a motor as a drive source. The chuck 180 is configured to be rotatable about a vertical axis by the rotation mechanism 181.

[0041] An image acquisition unit 190 is provided on the side of the chuck 180, on the negative Y-axis side. The image acquisition unit 190 has a configuration similar to that of the image acquisition unit 130 described above, and includes a light-projecting unit 191 and a light-receiving unit 192. The light-projecting unit 191 and the light-receiving unit 192 are arranged so that an optical axis A passes through the peripheral portion of the overlapped wafer T (the peripheral portion We of the first wafer W). The image acquisition unit 190 irradiates light from the light-projecting unit 191 toward the light-receiving unit 192, and acquires a projection image P including the peripheral portion of the overlapped wafer T, for example, as shown in FIG. 5 . The projection image P acquired by the image acquisition unit 190 is output to the control device 101 or the control device 200, which will be described later.

[0042] 2 , the wafer processing system 1 described above is provided with control units including a control device 71, a control device 81, a control device 91, a control device 101, and at least one control device 200 as control sections. The control device 71 individually controls the operation of the first laser irradiation device 70. The control device 81 individually controls the operation of the second laser irradiation device 80. The control device 91 individually controls the operation of the third laser irradiation device 90. The control device 101 individually controls the operation of the inspection device 100. The control device 200 oversees the control of a series of wafer processes in the wafer processing system 1.

[0043] The control devices 71, 81, 91, 101, and 200 each process computer-executable instructions that cause the first laser irradiation device 70, the second laser irradiation device 80, the third laser irradiation device 90, the inspection device 100, and the wafer processing system 1 to perform various steps described in this disclosure. The control devices 71, 81, 91, 101, and 200 can each be configured to control each element of the first laser irradiation device 70, the second laser irradiation device 80, the third laser irradiation device 90, the inspection device 100, and the wafer processing system 1 to perform various steps described herein. In one embodiment, some or all of the control device 71 may be included in the first laser irradiation device 70, some or all of the control device 81 may be included in the second laser irradiation device 80, some or all of the control device 91 may be included in the third laser irradiation device 90, some or all of the control device 101 may be included in the inspection device 100, and some or all of the control device 200 may be included in the wafer processing system 1.

[0044] The control devices 71, 81, 91, 101, and 200 may each include a processing unit, a storage unit, and a communication interface. The control devices 71, 81, 91, 101, and 200 may each be realized by, for example, a computer. The processing unit may be configured to read a program providing logic or routines that enable various control operations from the storage unit and execute the read program to perform various control operations. This program may be stored in the storage unit in advance or may be acquired via a medium when needed. The acquired program is stored in the storage unit and read from the storage unit and executed by the processing unit. The medium may be various computer-readable storage media or a communication line connected to the communication interface. The storage medium may be temporary or non-temporary. The processing unit may be a CPU (Central Processing Unit) or one or more circuits. The storage unit may include a RAM (Random Access Memory), a ROM (Read Only Memory), a HDD (Hard Disk Drive), a SSD (Solid State Drive), or a combination thereof. The communication interface may communicate with the first laser irradiation device 70, the second laser irradiation device 80, the third laser irradiation device 90, the inspection device 100, and the wafer processing system 1 via a communication line such as a LAN (Local Area Network).

[0045] In this embodiment, the control devices 71, 81, 91, and 101 are individually installed for the first laser irradiation device 70, the second laser irradiation device 80, the third laser irradiation device 90, and the inspection device 100, respectively, but these control devices 71, 81, 91, and 101 may be configured integrally with the control device 200. In other words, the operations of the first laser irradiation device 70, the second laser irradiation device 80, the third laser irradiation device 90, and the inspection device 100 may be controlled by the control device 200.

[0046] Next, a description will be given of wafer processing performed using the wafer processing system 1 configured as described above. In this embodiment, the wafer processing involves edge trimming to remove the peripheral edge portion We of the first wafer W. In this embodiment, the first wafer W and the second wafer S are bonded together to form an overlapping wafer T in advance.

[0047] First, a FOUP F containing a plurality of overlapping wafers T is placed on the FOUP placement table 10 of the carry-in / out station 2 .

[0048] Next, the overlapped wafer T is removed from the FOUP F by the wafer transfer device 20 and transferred to the transition device 30. Subsequently, the overlapped wafer T is transferred to the inspection device 100 by the wafer transfer device 40.

[0049] In the inspection apparatus 100, the image acquisition unit 190 is used to acquire a projection image P1 including the peripheral portion of the laminated wafer T held on the chuck 180 (St11 in FIG. 10 ). At this time, the projection image P1 is acquired in the circumferential direction while the chuck 180 is rotated by the rotation mechanism 181. The projection image P1 also includes a projection image of at least the peripheral portion We of the first wafer W. The acquired projection image P1 is output from the inspection apparatus 100 to the control device 200.

[0050] The control device 200 determines processing conditions in St15 to St17, which will be described later, based on the projection image P1. Specifically, before St15, at least one of the irradiation position and output of the second laser light L2 is determined (St12 in FIG. 10). Before St16, at least one of the irradiation position and output of the first laser light L1 is determined (St13 in FIG. 10). Before St17, at least one of the height position and insertion amount of the insertion blade 120 is determined (St14 in FIG. 10). The method for determining these processing conditions in the control device 200 will be described later.

[0051] Next, the overlapped wafer T is transferred to the second laser irradiation device 80 by the wafer transfer device 40. In the second laser irradiation device 80, the overlapped wafer T held by the chuck 140 is irradiated with the second laser light L2 along the interface between the first wafer W and the second wafer S (the interface between the bonding film Fw and the bonding film Fs in the illustrated example) as shown in FIG. 11( a). The irradiation direction of the second laser light L2 is arbitrary, but for example, it is irradiated from the radially outer side toward the radially inner side. The radial width of the irradiation area of ​​the second laser light L2 is set to a width that allows the peripheral edge portion We of the first wafer W to be appropriately removed. This second laser light L2 forms a bonding strength reduced region R at the interface between the first wafer W and the second wafer S (St15 in FIG. 10). The irradiation of the second laser light L2 is performed while the chuck 140 is rotating, and the bonding strength reduced region R is formed in a ring shape in a plan view.

[0052] Here, the irradiation position and output of the second laser light L2 in St15 are determined by the control device 200 before St15 (St12 in FIG. 10).

[0053] 5, information about the boundary B between the bonded region Ac and the unbonded region Ae of the first wafer W and the second wafer S is obtained. As described above, the peripheral edge We of the first wafer W and the peripheral edge Ae of the second wafer S are each chamfered, and therefore, an unbonded region Ae where the first wafer W and the second wafer S are not bonded exists in the peripheral edge of the overlapped wafer T. Since the bonding strength reduced region R formed in St15 is formed in the bonding region Ac, the position of the radial outer end of the bonding strength reduced region R, i.e., the irradiation start position of the second laser light L2, is determined based on the information about the boundary B.

[0054] Furthermore, in St12, information on the position of the radial outer end of the first wafer W or the position of the radial outer end of the second wafer S is acquired from the projection image P1. For example, if the position of the radial outer end of the first wafer W or the position of the radial outer end of the second wafer S does not match, the radial irradiation position of the second laser light L2 changes. Therefore, the radial irradiation position of the second laser light L2 is determined depending on the position of the radial outer end of the first wafer W or the position of the radial outer end of the second wafer S.

[0055] Furthermore, in St12, information on the inclination of the back surface Wb of the peripheral portion We of the first wafer W is obtained from the projection image P1. The inclination of the back surface Wb is the inclination of the back surface Wb from horizontal. The inclination of the back surface Wb also includes the inclination of the back surface Wb due to warpage of the first wafer W. The irradiation position (focal position) of the second laser light L2 in the thickness direction is determined based on this inclination of the back surface Wb. Here, in a three-dimensional integration technology that stacks semiconductor devices three-dimensionally, desired processes are repeatedly performed on the first wafer W, and the surface shape of the chamfered peripheral portion We changes over time. Specifically, for example, unevenness occurs on the surface of the peripheral portion We, or the inclination of the surface of the peripheral portion We changes. If such unevenness or inclination exists on the surface of the peripheral portion We, there is a concern that accurate measurement cannot be performed when measuring the height position of the back surface Wb (top surface) of the first wafer W using a laser displacement meter from above the first wafer W as in the conventional method, and there is room for improvement. Therefore, in St12, the irradiation position of the second laser light L2 in the thickness direction is determined based on the inclination of the back surface Wb.

[0056] Furthermore, in St12, information on the shape of the back surface Wb at the peripheral portion We of the first wafer W is obtained from the projection image P1. The shape of the back surface Wb is the roughness of the back surface Wb, that is, the state of the unevenness. For example, if the unevenness of the back surface Wb is large, the second laser light L2 is scattered by the back surface Wb, and the reflectance of the second laser light L2 varies depending on the shape of the back surface Wb. Therefore, the output of the second laser light L2 is determined depending on the shape of the back surface Wb.

[0057] Furthermore, in St12, as described above, information on the inclination of the back surface Wb of the peripheral portion We of the first wafer W is obtained from the projection image P1. For example, if the inclination of the back surface Wb is large, the second laser light L2 is largely reflected by the back surface Wb, and the reflectance of the second laser light L2 varies depending on the projection of the back surface Wb. Therefore, the output of the second laser light L2 is determined depending on the inclination of the back surface Wb.

[0058] In addition, in St12, the output of the second laser light L2 may be determined using information on either the shape or the inclination of the back surface Wb of the peripheral portion We, or the output of the second laser light L2 may be determined using information on both the shape and the inclination of the back surface Wb.

[0059] In this embodiment, the irradiation position and output of the second laser light L2 are determined based on the projection image P1 acquired by the image acquisition unit 190 of the inspection device 100, but the projection image P1 may be acquired by the image acquisition unit 160 of the second laser irradiation device 80, and the irradiation position and output of the second laser light L2 may be determined based on the projection image P1.

[0060] Next, the overlapped wafer T with the bond strength reduced region R formed therein is transferred to the first laser irradiation device 70 by the wafer transfer device 40. In the first laser irradiation device 70, the overlapped wafer T held by the chuck 140 is irradiated with a first laser beam L1 along the boundary between the peripheral edge portion We and the central portion We of the first wafer W, as shown in FIG. 11B. The boundary between the peripheral edge portion We and the central portion We is, for example, a boundary extending in the thickness direction of the first wafer W. When the peripheral modified layer M is formed by this laser beam L1, a crack C extends from the peripheral modified layer M along the boundary between the peripheral edge portion We and the central portion We. A peripheral modified region N including the peripheral modified layer M and the crack C is then formed (St16 in FIG. 10). The crack C connects to the bond strength reduced region R, and the peripheral modified region N extends between the back surface Wb of the first wafer W and the bond strength reduced region R. The first laser beam L1 is irradiated while the chuck 140 is rotated, and the peripheral modified region N is formed in a ring shape in a plan view.

[0061] In this embodiment, the peripheral modified region N extends in the thickness direction, but the shape of the peripheral modified region N is not limited to this. For example, the lower portion of the peripheral modified region N may be curved, or the entire peripheral modified region N may have a curved shape that is convex downward. Furthermore, for example, the peripheral modified region N may have a linear shape that slopes from the inner side to the outer side in the radial direction of the first wafer W from the back surface Wb to the front surface Wa of the first wafer W.

[0062] Here, the irradiation position and output power of the first laser beam L1 in St16 are determined by the control device 200 before St16 (St13 in FIG. 10 ). The method for determining the irradiation position and output power of the first laser beam L1 in St13 is the same as the method for determining the irradiation position and output power of the second laser beam L2 in St12. That is, in St13, information on the position of the radial outer end of the first wafer W or the position of the radial outer end of the second wafer S is obtained, for example, from the projection image P1 shown in FIG. 5 , and the radial irradiation position of the first laser beam L1 is determined based on the information. Also, in St13, information on the inclination of the back surface Wb of the peripheral portion We of the first wafer W is obtained, for example, from the projection image P1 shown in FIG. 5 , and the irradiation position of the first laser beam L1 in the thickness direction is determined based on the information. In addition, in St13, back surface information of at least one of the shape of the back surface Wb at the peripheral portion We of the first wafer W or the inclination of the back surface Wb is obtained, for example, from the projection image P1 shown in Figure 5, and the output of the first laser light L1 is determined based on the back surface information.

[0063] Conventionally, information about the back surface (top surface) of the first wafer has been obtained by measuring the position of the first wafer from above using a laser displacement meter. In such cases, accurate measurement is not possible if the peripheral surface is uneven or inclined. In this regard, according to the present embodiment, back surface information of the first wafer W can be appropriately obtained from the projection image P1, and the output of the first laser light L1 can be accurately determined.

[0064] In this embodiment, the irradiation position and output of the first laser light L1 are determined based on the projection image P1 acquired by the image acquisition unit 190 of the inspection device 100, but the projection image P1 may be acquired by the image acquisition unit 160 of the first laser irradiation device 70, and the irradiation position and output of the first laser light L1 may be determined based on the projection image P1.

[0065] In this embodiment, the position of the notch of the first wafer W may be determined from the circumferential projection image P1, and the profile (energy density distribution) of the first laser light L1 may be determined according to the position of the notch.

[0066] Next, the overlapped wafer T with the peripheral modified region N formed thereon is transferred by the wafer transfer device 40 to the peripheral removal device 50. In the peripheral removal device 50, the insertion blade 120 is inserted between the first wafer W and the second wafer S of the overlapped wafer T held by the chuck 110, as shown in FIG. 11(c), and the peripheral portion We is removed from the first wafer W (St17 in FIG. 10). At this time, the peripheral portion We is peeled and removed from the central portion We of the first wafer W, using the peripheral modified region N and the bonding strength reduced region R as base points.

[0067] Here, the height position and insertion amount of the insertion blade 120 in St17 are determined by the control device 200 before St17 (St14 in FIG. 10).

[0068] In St14, information on the shape of the peripheral edge We of the first wafer W and the position of the radially outer edge of the first wafer W is acquired, for example, from the projection image P1 shown in FIG. 5 . Based on this information, the height position H at which the insertion blade 120 contacts the first wafer W is determined, as shown in FIG. 12( a). The position at which the insertion blade 120 contacts the first wafer W is preferably the boundary D between the apex and the bevel at the peripheral edge We. This boundary D varies depending on the shape of the peripheral edge We of the first wafer W and the position of the radially outer edge of the first wafer W, so the height position H of the insertion blade 120 is determined based on this information. When the projection image P1 is used in this manner, the boundary D between the apex and the bevel at the peripheral edge We can be set to a more accurate position than, for example, conventionally when measuring the lateral distance of the first wafer using a laser displacement meter from the side of the first wafer. Therefore, the height position H of the insertion blade 120 can be accurately determined to a desired position. In this embodiment, the height position H is the height position of the insertion blade 120 from the interface between the first wafer W and the second wafer S, but the reference height position is arbitrary and may be, for example, the height from the wafer holding surface of the chuck 110.

[0069] Furthermore, in St14, the insertion amount E of the insertion blade 120 is determined as shown in FIG. 12( b) based on information about the shape of the peripheral edge We of the first wafer W and the position of the radially outer end of the first wafer W. The insertion amount E of the insertion blade 120 is the position from the position where the insertion blade 120 abuts the first wafer W shown in FIG. 12( a) to the position where the insertion of the insertion blade 120 ends. When the projection image P1 is used in this manner, the insertion end position of the insertion blade 120 can be set to a desired position, compared to, for example, a conventional method of measuring the lateral distance of the first wafer using a laser displacement meter from the side of the first wafer. Therefore, the insertion amount E of the insertion blade 120 can be accurately determined to be the desired insertion amount.

[0070] In this embodiment, the height position H and the insertion amount E of the insertion blade 120 are determined based on the projection image P1 acquired by the image acquisition unit 190 of the inspection device 100, but the projection image P1 may be acquired by the image acquisition unit 130 of the edge removal device 50, and the height position H and the insertion amount E of the insertion blade 120 may be determined based on the projection image P1. Furthermore, after St16, the overlapped wafer T may be transported to the inspection device 100, and the projection image P1 may be acquired again in the inspection device 100, and the height position H and the insertion amount E of the insertion blade 120 may be determined based on the projection image P1.

[0071] Furthermore, during removal of the peripheral edge portion We from the first wafer W in St17, the image acquisition unit 130 may acquire a projection image P. This projection image P is output to the control device 200, and the removal status of the peripheral edge portion We is monitored in the control device 200. In this case, the peripheral edge portion We can be reliably removed from the first wafer W.

[0072] Next, the overlapped wafer T from which the peripheral edge portion We has been removed is transferred to the inspection device 100 by the wafer transfer device 40. In the inspection device 100, the image acquisition unit 190 is used to acquire a projection image P2 including the peripheral edge portion of the overlapped wafer T held on the chuck 180 (St18 in FIG. 10 ). At this time, the rotation mechanism 181 rotates the chuck 180, while acquiring the projection image P2 in the circumferential direction. The projection image P2 also includes a projection image of at least the peripheral edge portion We of the first wafer W. The acquired projection image P2 is output from the inspection device 100 to the control device 200.

[0073] The control device 200 inspects whether the peripheral edge We has been properly removed from the first wafer W based on the projection image P2 (St19 in FIG. 10 ). The control device 200 acquires, from the projection image P2, the shape of the removed portion Wr of the first wafer W from which the peripheral edge We has been removed (hereinafter referred to as the “post-measurement shape”), as shown in FIG. 13 . The control device 200 also pre-stores a reference shape of the removed portion of the first wafer W after the peripheral edge We has been properly removed from the first wafer W. Then, in St19, the control device 200 compares the post-measurement shape of the removed portion Wr of the first wafer W with the reference shape to determine whether the peripheral edge We has been removed. Using the projection image P2 in this manner is effective in improving, for example, the cross-sectional shape of the removed peripheral edge We and the detection of incompletely removed portions, compared to, for example, conventional detection from above the first wafer.

[0074] The criteria for St19 include at least one of the inclination angle in the thickness direction of the removed portion Wr, the position of the bottom end of the removed portion Wr, or the surface shape of the removed portion Wr. The inclination angle in the thickness direction of the removed portion Wr is the inclination angle θ of the side surface Wra from the vertical direction. The position of the bottom end of the removed portion Wr is the position of the bottom end of the bottom surface Wrb. The surface shape of the removed portion Wr is the surface roughness (uneven shape) of the side surface Wra and the bottom surface Wrb, and the linearity of these side surface Wra and the bottom surface Wrb. Furthermore, according to the above criteria, if the measured shape of the removed portion Wr and the reference shape match with a certain tendency, it is determined that the peripheral portion We has been properly removed.

[0075] Furthermore, when a circumferential projection image P2 is acquired in St18, the judgment criteria in St19 include at least one of the circumferential variation in the inclination angle in the thickness direction of the removed portion Wr or the circumferential variation in the lower end position of the removed portion Wr.

[0076] In this embodiment, the possibility of removing the peripheral portion We is inspected based on the projection image P2 acquired by the image acquisition unit 190 of the inspection device 100, but the possibility of removing the peripheral portion We may also be inspected by acquiring the projection image P2 by the image acquisition unit 130 of the peripheral removal device 50.

[0077] Next, the overlapped wafer T from which the peripheral portion We has been removed is transferred by the wafer transfer device 40 to the third laser irradiation device 90. In the third laser irradiation device 90, the overlapped wafer T held by the chuck 140 is irradiated with third laser light L3 onto the surface films (bonding films Fw, Fs and device layers Dw, Ds) on the peripheral portion of the surface Sa of the second wafer S, as shown in FIG. 11( d ). The third laser light L3 removes the surface film on the peripheral portion of the surface Sa of the second wafer S by laser ablation (St20 in FIG. 10 ).

[0078] Next, the overlapped wafer T from which the surface film on the surface Sa of the second wafer S has been removed is transferred to the inspection device 100 by the wafer transfer device 40. In the inspection device 100, the image acquisition unit 190 is used to acquire a projection image P3 including the peripheral portion of the overlapped wafer T held on the chuck 180 (St21 in FIG. 10 ). At this time, the rotation mechanism 181 rotates the chuck 180, while acquiring the projection image P3 in the circumferential direction. The projection image P3 also includes a projection image of at least the peripheral portion We of the first wafer W. The acquired projection image P3 is output from the inspection device 100 to the control device 200.

[0079] The control device 200 inspects whether the surface film has been properly removed from the surface Sa of the second wafer S based on the projection image P3 (St22 in FIG. 10). The control device 200 acquires the shape of the surface Sa of the second wafer S from which the surface film has been removed (hereinafter referred to as the "post-measurement shape") from the projection image P3. The control device 200 also stores in advance a reference shape of the surface Sa of the second wafer S from which the surface film has been properly removed. Then, in St22, the post-measurement shape of the surface Sa of the second wafer S is compared with the reference shape to determine whether the surface film has been removed.

[0080] In this embodiment, whether or not the surface film of the second wafer can be removed is inspected based on the projection image P3 acquired by the image acquisition unit 190 of the inspection device 100, but whether or not the surface film of the second wafer S can be removed may also be inspected by acquiring the projection image P3 by the image acquisition unit 160 of the third laser irradiation device 90.

[0081] Next, the laminated wafer T from which the surface film of the second wafer S has been removed is transferred by the wafer transfer device 40 to the cleaning device 60. In the cleaning device 60, the first wafer W and the second wafer S are cleaned (St23 in FIG. 10).

[0082] Thereafter, the laminated wafer T that has been subjected to all the processes is transferred by the wafer transfer device 40 to the transition device 30, and further transferred by the wafer transfer device 20 to the FOUP F on the FOUP mounting table 10. In this way, the series of wafer processes in the wafer processing system 1 is completed.

[0083] According to the above embodiment, in St12, the irradiation position and output of the second laser light L2 can be determined based on the projection image P1. That is, information on the position of the radial outer end of the first wafer W or the position of the radial outer end of the second wafer S is obtained from the projection image P1, and the radial irradiation position of the second laser light L2 is determined based on this information. Also, information on the inclination of the back surface Wb of the peripheral portion We of the first wafer W is obtained from the projection image P1, and the irradiation position of the second laser light L2 in the thickness direction is determined based on this information. Also, back surface information on at least one of the shape of the back surface Wb of the peripheral portion We of the first wafer W or the inclination of the back surface Wb is obtained from the projection image P1, and the output of the second laser light L2 is determined based on this back surface information. Therefore, for example, even if the surface of the peripheral portion We of the first wafer W is uneven or the inclination of the surface of the peripheral portion We changes, the irradiation position and output of the second laser light L2 can be appropriately set in St15. As a result, in St15, the irradiation energy of the second laser light L2 can be transmitted to the interface between the first wafer W and the second wafer S, and the bonding strength reduced region R can be appropriately formed.

[0084] Furthermore, since the inspection device 100 acquires the circumferential projection image P1 in St11, the irradiation position and output of the second laser light L2 can be determined according to the circumferential position in St12. Therefore, the bonding strength reduction region R can be appropriately formed in the circumferential direction in St15.

[0085] Furthermore, in St12, information on the boundary B between the bonded region Ac and the unbonded region Ae of the first wafer W and the second wafer S is obtained from the projection image P1, and the position of the radial outer end of the bonding strength reduced region R, i.e., the irradiation start position of the second laser light L2, can be appropriately determined. As a result, in St15, irradiation of the unbonded region Ae with the second laser light L2 can be suppressed, and unnecessary consumption of irradiation energy can be suppressed. Furthermore, the irradiation time of the second laser light L2 can be shortened, and the throughput of wafer processing can also be improved.

[0086] Also in St 13, the irradiation position and output of the first laser beam L1 can be determined in the same manner as the method for determining the irradiation position and output of the second laser beam L2 in St 12. As a result, in St 6, the irradiation energy of the first laser beam L1 can be transmitted to the inside of the first wafer W, and the peripheral modified region N can be appropriately formed.

[0087] Furthermore, since the inspection device 100 acquires the circumferential projection image P1 in St11, the irradiation position and output of the first laser beam L1 can be determined according to the circumferential position in St13. Therefore, the peripheral modified region N can be appropriately formed in the circumferential direction in St16.

[0088] Furthermore, in St14, the height position H and insertion amount E of the insertion blade 120 can be determined based on the projection image P1. That is, information on the shape of the peripheral portion We of the first wafer W and the position of the radial outer end of the first wafer W is acquired from the projection image P1, and the height position H of the insertion blade 120 abutting the first wafer W and the insertion amount E of the insertion blade 120 are determined based on this information. When the projection image P1 is used in this manner, the boundary D between the apex and bevel of the peripheral portion We can be set to a more accurate position than in the conventional case where the distance to the side of the first wafer is measured using a laser displacement meter from the side of the first wafer, and the height position H and insertion amount E of the insertion blade 120 can be accurately determined. Therefore, even if, for example, unevenness occurs on the surface of the peripheral portion We of the first wafer W or the slope of the surface of the peripheral portion We changes, the height position H and insertion amount E of the insertion blade 120 can be appropriately set in St17, and as a result, the peripheral portion We can be appropriately removed.

[0089] Furthermore, in St19, whether or not the peripheral edge We has been properly removed from the first wafer W is inspected based on the projected image P2, which is effective in improving the detection of the cross-sectional shape of the removed peripheral edge We and the detection of parts that were not completely removed, compared to, for example, conventional detection using a laser displacement meter from above the first wafer. Furthermore, the inspection can be performed efficiently in a short time, compared to, for example, visual confirmation by an operator.

[0090] In addition, in St18, the inspection device 100 acquires the circumferential projection image P2, so in St19, it is possible to inspect in the circumferential direction whether the peripheral edge portion We can be removed.

[0091] Note that, in St19, when it is determined that the peripheral edge We has not been properly removed from the first wafer W, a response method is arbitrarily determined depending on the removal status of the peripheral edge We. For example, an alarm may be output as an error of the wafer processing system 1. Alternatively, for example, the abnormal overlapped wafer T determined to have the peripheral edge We not properly removed may be temporarily stored, and when the peripheral edge We of the subsequent overlapped wafer T is successfully removed, the abnormal overlapped wafer T may be transported again to the peripheral edge removal device 50 for reprocessing (rework). Alternatively, for example, when the peripheral edge We of the subsequent overlapped wafer T after the abnormal overlapped wafer T is not properly removed either, the processing conditions of the first laser irradiation device 70, the second laser irradiation device 80, the peripheral edge removal device 50, etc. may be feedback-controlled.

[0092] Furthermore, in St22, whether or not the surface film has been properly removed from the surface Sa of the second wafer S is inspected based on the projection image P3, which is effective in improving the detection of the surface shape of the second wafer S after the surface film has been removed and the detection of parts that were not completely removed, compared to the conventional method of detecting using a laser displacement meter from above the first wafer. Furthermore, the inspection can be performed efficiently in a short time, compared to the case where the inspection is performed by visual confirmation by an operator, for example.

[0093] Furthermore, in St21, the inspection device 100 acquires the circumferential projection image P3, so that in St22, it is possible to inspect in the circumferential direction whether or not the surface film of the second wafer S can be removed.

[0094] In the above embodiment, so-called eccentricity correction may be performed in each of the irradiation process of the second laser light L2 in St15, the irradiation process of the first laser light L1 in St16, and the irradiation process of the third laser light L3 in St20.

[0095] For example, in St11, the control device 200 determines the radial outer end portions of the first wafer W and the second wafer S based on the projection image P1 acquired by the image acquisition unit 190 of the inspection device 100. Here, if the positions of the outer end portions of the first wafer W and the second wafer S are misaligned in a plan view, that is, if there is a horizontal misalignment between the first wafer W and the second wafer S, there is a risk that the laser beams L1 to L3 may not be irradiated at the desired radial positions. Therefore, the radial irradiation positions of the laser beams L1 to L3 are determined so as to correct the eccentricity of the first wafer W and the second wafer S.

[0096] In this case, the second laser beam L2 can be irradiated to a desired radial position in St15, thereby forming the bonding strength reduced region R at an appropriate position. Furthermore, the first laser beam L1 can be irradiated to a desired radial position in St16, thereby forming the peripheral modified region N at an appropriate position. The third laser beam L3 can be irradiated to a desired radial position in St20, thereby appropriately removing the surface film of the second wafer S.

[0097] In the above-described embodiment of the peripheral edge removal device 50, the configuration of the peripheral edge removal unit is not limited to the insertion blade 120. For example, as shown in FIG. 14 , the peripheral edge removal device 50 may have a cutting blade 300 as a cutting member. The cutting blade 300 is configured to be movable horizontally and vertically by a movement mechanism (not shown) and is also configured to be rotatable. The cutting blade 300 is rotated while being in contact with the back surface Wb (top surface) of the peripheral edge portion We of the first wafer, and the cutting blade 300 is lowered to remove the peripheral edge portion We. In this embodiment, the cutting blade 300 and the movement mechanism constitute the peripheral edge removal unit.

[0098] The control device 200 determines at least one of the cutting start position H1 and the cutting end position H2 of the cutting blade 300 based on the projection image P1. Specifically, for example, information on the shape of the peripheral edge We of the first wafer W and the position of the radial outer edge of the first wafer W is acquired from the projection image P1 shown in FIG. 5 . Based on this information, the control device 200 determines the cutting start position H1 of the cutting blade 300, where the cutting blade 300 comes into contact and starts cutting the peripheral edge We, as shown in FIG. 14( a). Also, based on this information, the control device 200 determines the cutting end position H2 of the cutting blade 300, where removal of the peripheral edge We is completed, as shown in FIG. 14( b). Note that in this embodiment, the cutting start position H1 and the cutting end position H2 are height positions of the cutting blade 300 from the interface between the first wafer W and the second wafer S, but the reference height positions are arbitrary.

[0099] In such a case, even if, for example, unevenness occurs on the surface of the peripheral portion We of the first wafer W or the slope of the surface of the peripheral portion We changes, the cutting start position H1 and cutting end position H2 of the cutting blade 300 can be appropriately set, and as a result, the peripheral portion We can be appropriately removed.

[0100] Furthermore, since the cutting start position H1 of the cutting blade 300 can be appropriately set, the cutting blade 300 can be lowered to the cutting start position H1 at a high speed, and the peripheral edge portion We can be removed in a short time, thereby improving the throughput of wafer processing.

[0101] Furthermore, the image acquisition unit 130 may acquire a projection image P while the peripheral edge portion We is being removed from the first wafer W. This projection image P is output to the control device 200, and the removal status of the peripheral edge portion We is monitored in the control device 200. In this case, the peripheral edge portion We can be reliably removed from the first wafer W.

[0102] In the above embodiment, the overlapped wafer T may have a back surface film (e.g., an oxide film) formed on the back surface Wb (upper surface) of the first wafer W before the wafer processing steps St11 to St23 are performed in the wafer processing system 1. If such a back surface film is formed, the second laser beam L2, the first laser beam L1, and the third laser beam L3 may be obstructed by the back surface film and may not be irradiated to appropriate positions in St15, St16, and St20. Therefore, the back surface film is removed before the irradiation process of the second laser beam L2 in St15, the irradiation process of the first laser beam L1 in St16, and the irradiation process of the third laser beam L3 in St20 are performed.

[0103] For example, at least before the irradiation process of the second laser light L2 is performed in St15, the overlapped wafer T is transferred by the wafer transfer device 40 to the third laser irradiation device 90. In the third laser irradiation device 90, the overlapped wafer T held by the chuck 140 is irradiated with the third laser light L3 onto a back surface film (not shown) on the back surface Wb of the first wafer W, as shown in FIG. 15 , the back surface film of the first wafer W is removed by laser ablation with the third laser light L3.

[0104] In such a case, information on the shape of the back surface film (back surface Wb of the first wafer W) may be obtained, for example, from the projection image P1, and based on this information, the back surface film may be removed and flattened using a processing liquid, or the back surface film may be removed and flattened by grinding or laser light irradiation.

[0105] Here, the irradiation position and output of the third laser light L3 when removing the backside film of the first wafer W are determined by the control device 200. The method for determining the irradiation position and output of the third laser light L3 is similar to the method for determining the irradiation position and output of the second laser light L2 in St12, for example. That is, for example, information on the position of the radial outer end of the first wafer W or the position of the radial outer end of the second wafer S is obtained from the projection image P1 shown in FIG. 5, and the radial irradiation position of the third laser light L3 is determined based on this information. Also, for example, information on the inclination of the backside Wb at the peripheral portion We of the first wafer W is obtained from the projection image P1 shown in FIG. 5, and the irradiation position in the thickness direction of the third laser light L3 is determined based on this information. Also, for example, backside information on at least one of the shape of the backside Wb at the peripheral portion We of the first wafer W or the inclination of the backside Wb is obtained from the projection image P1 shown in FIG. 5, and the output of the third laser light L3 is determined based on this backside information.

[0106] The thickness of the rear surface film is acquired in advance. Then, the above information is acquired from the projection image P1, and the irradiation position and output of the third laser light L3 are determined.

[0107] Next, the laminated wafer T from which the back surface film of the first wafer W has been removed is transported to the inspection device 100 by the wafer transport device 40. In the inspection device 100, the image acquisition unit 190 is used to acquire a projection image P including the peripheral portion of the laminated wafer T held on the chuck 180. At this time, the projection image P is acquired in the circumferential direction while the chuck 180 is rotated by the rotation mechanism 181. The projection image P also includes a projection image of the entire back surface Wb of the first wafer W. The acquired projection image P is output from the inspection device 100 to the control device 200.

[0108] The control device 200 inspects whether the back surface film has been properly removed from the back surface Wb of the first wafer W based on the projection image P. The control device 200 acquires the shape of the back surface Wb of the first wafer W from which the back surface film has been removed (hereinafter referred to as the "post-measurement shape") from the projection image P. The control device 200 also stores in advance a reference shape of the back surface Wb of the first wafer W from which the back surface film has been properly removed. The control device 200 then compares the post-measurement shape of the back surface Wb of the first wafer W with the reference shape to determine whether the back surface film can be removed.

[0109] In this case, whether or not the back surface film has been appropriately removed from the back surface Wb of the first wafer W is inspected based on the projection image P, so the inspection can be performed more efficiently in a shorter time than when, for example, the inspection is performed using a plurality of sensors or measuring instruments or when the inspection is performed by visual confirmation by an operator. Furthermore, because the inspection apparatus 100 acquires the projection image P in the circumferential direction, it is possible to inspect whether or not the back surface film of the first wafer W has been appropriately removed in the circumferential direction in St22.

[0110] In the above embodiment, the peripheral portion We is removed from the first wafer W using the peripheral modified region N and the bonding strength reduced region R as base points, but the base points for removing the peripheral portion We are not limited to this. For example, as shown in FIG. 16 , the peripheral portion We may be removed using the first peripheral modified region N1 and the second peripheral modified region N2 as base points.

[0111] In such a case, in the wafer processing system 1, first, the image acquisition unit 190 in the inspection device 100 acquires a projection image P1 including the peripheral portion of the overlapped wafer T held on the chuck 180 (Step 101 in FIG. 17). This Step 101 is the same as Step 11 in the above embodiment.

[0112] Next, the control device 200 determines processing conditions in St105 to St107 (described later) based on the projection image P1. Specifically, in St105, at least one of the irradiation position and output of the first laser beam L1 is determined (St102 in FIG. 17). In St106, at least one of the irradiation position and output of the first laser beam L1 is determined (St103 in FIG. 17). In St107, at least one of the height position and insertion amount of the insertion blade 120 is determined (St104 in FIG. 17). Note that St102 and St103 are the same as St13 in the above embodiment. Also, St104 is the same as St14 in the above embodiment.

[0113] Next, in the first laser irradiation device 70, a first peripheral modified region N1 and a second peripheral modified region N2 are formed inside the first wafer W. In this embodiment, the first peripheral modified region N1 and the second peripheral modified region N2 are formed in this order (St105 and St106 in FIG. 17 ).

[0114] 16( a), when forming the first peripheral modified region N1, a first laser beam L1 is irradiated into the interior of the first wafer W along the radially inner side surface of the upper peripheral edge Wea to be removed by the peripheral edge removal device 50. At this time, the first laser beam L1 is irradiated based on the irradiation position and output determined in St102. When the first peripheral modified layer M1 is formed by the first laser beam L1, a first crack C1 extends from the first peripheral modified layer M1 along the side surface of the upper peripheral edge Wea. Then, a first peripheral modified region N1 including the first peripheral modified layer M1 and the first crack C1 is formed.

[0115] The first peripheral modified region N1 is formed from bottom to top along the side surface of the upper peripheral edge Wea. The first peripheral modified region N1 extends from the back surface Wb (top) of the first wafer W to the front surface Wa (bottom) of the first wafer W, inclining from the inside to the outside in the radial direction of the first wafer W, or the lower part of the first peripheral modified region N1 curves downward in a convex curved shape in side view. As will be described later, the second peripheral modified region N2 is formed horizontally from the lower end of the first peripheral modified region N1 radially outward.

[0116] 16(b), when forming the second peripheral modified layer M2, the first laser beam L1 is irradiated into the interior of the first wafer W along the bottom surface of the upper peripheral portion Wea. At this time, the first laser beam L1 is irradiated based on the irradiation position and output determined in St103. When the second peripheral modified layer M2 is formed by the first laser beam L1, a second crack C2 extends from the second peripheral modified layer M2 along the bottom surface of the upper peripheral portion Wea. A second peripheral modified region N2 including the second peripheral modified layer M2 and the second crack C2 is then formed.

[0117] The second peripheral modified layer M2 may be formed from the outside to the inside in the radial direction, or from the inside to the outside in the radial direction. In other words, the radial irradiation direction of the laser light is arbitrary.

[0118] The second peripheral modified layer M2 is formed by extending horizontally in a straight line radially outward from the lower end of the first peripheral modified region N1. In this embodiment, the first peripheral modified layer M1 at the lower end of the first peripheral modified region N1 is located at the intersection of the first peripheral modified region N1 and the second peripheral modified region N2, and a crack that occurs between the second peripheral modified region N2 and the lower first peripheral modified layer M1 connects the second crack C2 in the second peripheral modified region N2 to the lower first peripheral modified layer M1.

[0119] These first peripheral modified region N1 and second peripheral modified region N2 serve as base points when removing the upper peripheral edge Wea. The order in which the first peripheral modified region N1 and the second peripheral modified region N2 are formed is arbitrary.

[0120] Next, in the edge removal device 50, the insertion blade 120 is inserted between the first wafer W and the second wafer S as shown in FIG. 16(c), and the upper edge Wea is removed from the first wafer W (St107 in FIG. 17). At this time, the insertion blade 120 is irradiated based on the height position and insertion amount determined in St104. Then, the upper edge Wea is peeled and removed from the central portion Wc of the first wafer W, using the first peripheral modified region N1 and the second peripheral modified region N2 as base points. In addition, the lower edge Web remains on the peripheral portion We of the first wafer W.

[0121] Next, the inspection device 100 acquires a projection image P2 (St108 in FIG. 17 ), and the control device 200 inspects whether the peripheral edge We can be removed from the first wafer W based on the projection image P2 (St109 in FIG. 17 ). St108 and St109 are similar to St18 and St19 in the above embodiment, respectively.

[0122] 16(d), in the third laser irradiation device 90, the third laser light L3 is irradiated onto the lower peripheral edge Web and the surface film (bonding films Fw, Fs and device layers Dw, Ds) on the peripheral portion of the surface Sa of the second wafer S. This third laser light L3 removes the lower peripheral edge Web and the surface film on the peripheral portion of the surface Sa of the second wafer S by laser ablation (St110 in FIG. 17).

[0123] Next, the inspection device 100 acquires a projection image P3 (St111 in FIG. 17), and the control device 200 inspects whether the lower peripheral edge Web and the surface film of the second wafer S can be removed based on the projection image P3 (St112 in FIG. 17). St111 and St112 are similar to St21 and St22 in the above embodiment, respectively.

[0124] Next, the first wafer W and the second wafer S are cleaned in the cleaning device 60 (St113 in FIG. 17). This St113 is similar to St23 in the above embodiment.

[0125] This embodiment also provides the same advantages as the above-described embodiment. That is, in St102, the irradiation position and output of the first laser beam L1 are determined based on the projection image P1, so that the first peripheral modified region N1 can be appropriately formed. Furthermore, in St103, the irradiation position and output of the first laser beam L1 are determined based on the projection image P1, so that the second peripheral modified region N2 can be appropriately formed.

[0126] In this embodiment, the peripheral portion We may be removed from the first peripheral modified region N1 and the second peripheral modified region N2 as starting points while grinding the entire back surface Wb of the first wafer W using a grinding device (not shown). In such a case, the grinding device also serves as the peripheral removal unit.

[0127] The technology disclosed herein can also be applied to a case where a modified region is formed in the surface direction by irradiating the entire surface of the interface between the first wafer W and the second wafer S with laser light in the surface direction. In this case, the first wafer W is separated from the second wafer S using the modified region as a base point, thereby performing so-called laser lift-off.

[0128] For example, in the inspection device 100, at least one of the chuck 180 and the image acquisition unit 190 is moved in the radial direction to acquire a projection image of the entire radial direction of the overlapped wafer T. Then, as in the above embodiment, the irradiation position and output of the laser light are determined based on the projection image, and the entire interface between the first wafer W and the second wafer S is irradiated with the laser light in the surface direction.

[0129] In this case, the same effects as those of the above embodiment can be obtained. That is, a modified region can be formed at a desired position inside the first wafer W, and the first wafer W can be appropriately separated from the second wafer S using the modified region as a base point. Note that projected images of the entire radial direction of the overlapped wafer T can also be acquired by the other image acquisition units 130 and 160 in a similar manner.

[0130] Furthermore, when the image acquisition units 130, 160, and 190 acquire projection images of the entire radial direction of the overlapped wafer T as described above, the warpage in the center of the overlapped wafer T (first wafer W) can also be grasped.

[0131] The technology disclosed herein is not limited to processing of overlapped wafers T, but can also be applied to laser processing of a single wafer. For example, a projection image of the wafer is acquired in the inspection device 100. Then, as in the above embodiment, the irradiation position and output of the laser light are determined based on the projection image, and the laser light is irradiated onto the wafer. In such a case, the same effects as in the above embodiment can be obtained. That is, the laser light can be appropriately irradiated onto the wafer.

[0132] The technology disclosed herein can also be applied to cases where a desired process is performed on the upper surface of the peripheral edge of a wafer. For example, when supplying a processing liquid onto the peripheral edge of a wafer to form a desired film, a projection image of the wafer is acquired, for example, using the inspection device 100. Then, as in the above embodiment, the supply position and supply amount of processing liquid are determined based on the projection image, and the processing liquid is supplied to the upper surface of the peripheral edge to form a film. In such a case, the same effects as those of the above embodiment can be achieved. That is, the processing liquid can be appropriately supplied to the upper surface of the peripheral edge of the wafer, and the desired film can be formed.

[0133] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The above-described embodiments may be omitted, substituted, or modified in various ways without departing from the scope and spirit of the appended claims. For example, the components of the above-described embodiments may be arbitrarily combined. Such an arbitrary combination naturally provides the functions and effects of each of the components involved in the combination, and also provides other functions and effects that are apparent to those skilled in the art from the description of this specification.

[0134] Furthermore, the effects described herein are merely descriptive or exemplary and are not limiting. In other words, the technology according to the present disclosure may achieve other effects that would be apparent to a person skilled in the art from the description of this specification, in addition to or in place of the above-described effects.

[0135] REFERENCE SIGNS LIST 1 wafer processing system 70 first laser irradiation device 80 second laser irradiation device 90 third laser irradiation device 150 laser irradiation section 160 image acquisition section 200 control device S second wafer T overlapped wafer W first wafer

Claims

1. A substrate processing system for processing a substrate, comprising: a laser irradiation unit that irradiates the substrate with laser light from above the substrate; an image acquisition unit that acquires a projected image of the substrate from the side of the substrate; and a control unit, wherein the control unit performs the following controls: control to acquire the projected image with the image acquisition unit before the laser irradiation unit irradiates the substrate with the laser light; and control to determine at least either the irradiation position of the laser light on the substrate or the output power of the laser light based on the projected image before the laser light is irradiated.

2. The substrate processing system of claim 1, wherein the control unit performs control to acquire top surface information including at least one of the shape of the top surface of the substrate and the inclination of the top surface from the projected image before the irradiation of the laser light, and control to determine the output of the laser light based on the top surface information.

3. The substrate processing system of claim 1 or 2, wherein the substrate is a laminated substrate formed by bonding a first substrate and a second substrate, and the control unit executes the following controls: determining the outer edge of the first substrate and the outer edge of the second substrate from the projected image before the irradiation of the laser light, and deriving the amount of eccentricity of the first substrate and the second substrate; and determining the irradiation position of the laser light on the laminated substrate based on the amount of eccentricity.

4. The substrate processing system of claim 1 or 2, wherein the substrate is a laminated substrate formed by bonding a first substrate and a second substrate together, and the control unit executes the following controls: control to irradiate the interface between the first substrate and the second substrate with the laser light, and acquire the projection image with the image acquisition unit before forming a region of reduced bonding strength at the interface where the bonding strength has been reduced; control to acquire interface information between the first substrate and the second substrate from the projection image before the region of reduced bonding strength is formed; and control to determine a start position for irradiation of the laser light when forming the region of reduced bonding strength based on the interface information.

5. A substrate processing system as described in claim 1 or 2, wherein a film is formed on the upper surface of the substrate, and the control unit executes the following controls: control for the laser irradiation unit to irradiate the film with the laser light and remove the film; control for the image acquisition unit to acquire the projected image after the film has been removed; and control for determining whether the film can be removed based on the projected image after the film has been removed.

6. A substrate processing system as described in claim 1 or 2, wherein the substrate is a laminated substrate formed by bonding a first substrate and a second substrate, and the system includes a peripheral edge removal unit that removes a peripheral portion from the first substrate, and the control unit performs the following controls: after the peripheral portion is removed from the first substrate by the peripheral edge removal unit, the laser irradiation unit irradiates the laser light onto a film remaining on the peripheral portion of the second substrate to remove the film; after the film is removed, the image acquisition unit acquires the projected image; and based on the projected image after the film has been removed, determines whether the film can be removed.

7. A substrate processing system as described in claim 1 or 2, comprising: a substrate holding unit that holds the substrate; and a rotation mechanism that rotates the substrate holding unit, wherein the control unit performs the following control: before the laser irradiation unit irradiates the substrate with the laser light, the image acquisition unit acquires the projection image in the circumferential direction of the substrate while rotating the substrate held by the substrate holding unit with the rotation mechanism; and based on the projection image in the circumferential direction of the substrate, determines at least one of the irradiation position of the laser light on the substrate or the output of the laser light.

8. A substrate processing method for processing a substrate, comprising: acquiring a projection image of the substrate from the side of the substrate by an image acquisition unit before irradiating the substrate with laser light from above by a laser irradiation unit; and determining at least one of the irradiation position of the laser light on the substrate or the output of the laser light based on the projection image before the irradiation with the laser light.

9. A substrate processing method as described in claim 8, comprising: acquiring top surface information including at least one of the shape of the top surface of the substrate and the inclination of the top surface from the projection image before irradiation with the laser light; and determining the output of the laser light based on the top surface information.

10. The substrate processing method according to claim 8 or 9, wherein the substrate is a laminated substrate formed by bonding a first substrate and a second substrate, and the substrate processing method includes: determining the outer edges of the first substrate and the outer edges of the second substrate from the projected image before irradiation with the laser light, and deriving the amount of eccentricity of the first substrate and the second substrate; and determining the irradiation position of the laser light on the laminated substrate based on the amount of eccentricity.

11. The substrate processing method according to claim 8 or 9, wherein the substrate is a laminated substrate formed by bonding a first substrate and a second substrate together, and the substrate processing method includes: irradiating the interface between the first substrate and the second substrate with the laser light, and acquiring the projection image with the image acquisition unit before forming a region of reduced bonding strength at the interface where the bonding strength has been reduced; acquiring interface information between the first substrate and the second substrate from the projection image before the region of reduced bonding strength is formed; and determining a start position for irradiation of the laser light when forming the region of reduced bonding strength based on the interface information.

12. A substrate processing method according to claim 8 or 9, wherein a film is formed on an upper surface of the substrate, and the substrate processing method includes: irradiating the film with the laser light in the laser irradiation unit to remove the film; acquiring the projected image in the image acquisition unit after removing the film; and determining whether or not the film can be removed based on the projected image after the film has been removed.

13. The substrate processing method according to claim 8 or 9, wherein the substrate is a laminated substrate formed by bonding a first substrate and a second substrate, and the substrate processing method includes: removing a peripheral portion from the first substrate in an edge removal section, and then irradiating a film remaining on the peripheral portion of the second substrate with the laser light in the laser irradiation section to remove the film; acquiring the projected image in the image acquisition section after the film has been removed; and determining whether the film can be removed based on the projected image after the film has been removed.

14. A substrate processing method as described in claim 8 or 9, comprising: acquiring the projection image in the circumferential direction of the substrate by the image acquisition unit while rotating the substrate held in a substrate holding unit by a rotation mechanism before irradiating the substrate with the laser light by the laser irradiation unit; and determining at least one of the irradiation position of the laser light on the substrate or the output power of the laser light based on the projection image in the circumferential direction of the substrate.

15. A readable computer storage medium storing a program that runs on a computer of a control unit that controls a substrate processing system so as to cause the substrate processing system to execute the substrate processing method according to claim 8 or 9.

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