Substrate processing apparatus, program and storage medium

Abstract

To form a peripheral modification layer in an appropriate position in a polymerized substrate.SOLUTION: A modification apparatus includes: a substrate holding part 100 for holding a second substrate of a polymerized substrate obtained by bonding a first substrate and a second substrate together; a modification device 60 that irradiates laser light for forming, inside the first substrate in the held polymerized substrate, a modification layer along a boundary between a peripheral edge and a center section; a program storage unit that stores a program; and a control device that has a computer that operates the program. The polymerized substrate has a bonded area where the surface of the first substrate and the surface of the second substrate are bonded and an unbonded area that is the area radially outside the bonded area. The program is operated on the computer that controls a substrate processing apparatus so as to cause the substrate processing apparatus to execute a substrate processing method. The substrate processing method irradiates the laser light to the inner side in the radial direction relative to the outer edge of the bonded area such that the distance between the peripheral modification layer and the outer edge of the bonded area is within 500 μm.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to a substrate processing apparatus, a program, and a storage medium. [Background technology]

[0002] Patent Document 1 discloses a method for manufacturing a stacked semiconductor device. In this manufacturing method, two or more semiconductor wafers are stacked to manufacture a stacked semiconductor device. At this time, each semiconductor wafer is stacked on another semiconductor wafer, and then the backside of the semiconductor wafer is ground to a desired thickness.

[0003] Patent Document 2 discloses a method for grinding the peripheral edge of a semiconductor wafer in a substantially L-shape by rotating a disk-shaped grinding tool with abrasive grains on its outer periphery and bringing at least the outer periphery of the grinding tool into linear contact with the semiconductor wafer. The semiconductor wafer is made by bonding two silicon wafers together. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-69736 [Patent Document 2] Japanese Patent Application Publication No. 9-216152 Summary of the Invention [Problem to be solved by the invention]

[0005] The technology according to the present disclosure forms a peripheral modified layer at an appropriate position in a laminated substrate in which substrates are bonded together. [Means for solving the problem]

[0006] One aspect of the present disclosure is a substrate processing apparatus for processing substrates, comprising: a substrate holding unit for holding the second substrate in a laminated substrate formed by bonding a first substrate and a second substrate; a modification device having a lens for irradiating laser light inside the first substrate in the laminated substrate held by the substrate holding unit, the laser light forming a peripheral modified layer along the boundary between the peripheral portion and the central portion to be removed; a program storage unit for storing a program; and a control device having a computer for reading the program from the program storage unit and operating the program, wherein the laminated substrate has a bonded region where the surfaces of the first substrate and the second substrate are bonded, and an unbonded region which is a region radially outside the bonded region, and the program is a program running on the computer of the control device that controls the substrate processing apparatus to perform a substrate processing method, and the substrate processing method includes irradiating the laser light radially inward of the outer end of the bonded region so that the distance between the peripheral modified layer and the outer end of the bonded region is within 500 μm. [Effects of the Invention]

[0007] According to the present disclosure, a peripheral modified layer can be formed at an appropriate position in a laminated substrate in which substrates are bonded together. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a plan view schematically showing an outline of the configuration of a wafer processing system according to an embodiment of the present invention; [Figure 2] FIG. 2 is a side view showing an outline of the configuration of an overlapping wafer. [Figure 3] FIG. 2 is a side view showing an outline of a configuration of a part of the overlapping wafer. [Figure 4] FIG. 2 is a plan view showing the outline of the configuration of the reformer; [Figure 5] FIG. 2 is a side view showing the outline of the configuration of the reformer. [Figure 6] FIG. 2 is a plan view showing the outline of the configuration of the peripheral edge removing device. [Figure 7]FIG. 2 is a side view showing an outline of the configuration of the peripheral edge removing device. [Figure 8] FIG. 2 is a longitudinal cross-sectional view showing the outline of the configuration of a transfer arm. [Figure 9] FIG. 2 is a flowchart showing main steps of wafer processing according to the first embodiment. [Figure 10] 1A to 1C are explanatory views of main steps of wafer processing according to a first embodiment. [Figure 11] FIG. 2 is an explanatory diagram of main steps of the modification treatment. [Figure 12] 10A and 10B are explanatory views showing a state in which a peripheral modified layer is formed on a processing wafer. [Figure 13] 10A and 10B are explanatory views showing a state in which a peripheral modified layer is formed on a processing wafer. [Figure 14] 10A and 10B are explanatory views showing how divided modified layers are formed on a processing wafer. [Figure 15] 10 is an explanatory diagram showing a state in which divided modified layers are formed on a processing wafer. FIG. [Figure 16] 10A and 10B are explanatory views showing a state in which an internal surface modification layer is formed on a processing wafer. [Figure 17] 10A and 10B are explanatory views showing a state in which an internal surface modification layer is formed on a processing wafer. [Figure 18] FIG. 10 is an explanatory diagram showing the removal of the peripheral edge portion. [Figure 19] FIG. 10 is an explanatory view showing a state in which the back surface wafer is separated from the processing wafer. [Figure 20] FIG. 10 is a side view showing an outline of the configuration of a peripheral edge removing device according to another embodiment. [Figure 21] FIG. 10 is a plan view showing the outline of the configuration of a reformer according to another embodiment. [Figure 22] FIG. 10 is a plan view showing the outline of the configuration of a reformer according to another embodiment. [Figure 23] 10A to 10C are explanatory views of main steps of wafer processing according to a modified example of the first embodiment. [Figure 24] FIG. 10 is a flowchart showing main steps of wafer processing according to a second embodiment. [Figure 25] 10A to 10C are explanatory views of main steps of wafer processing according to a second embodiment. [Figure 26] FIG. 10 is an explanatory view showing a state in which the back surface wafer is separated from the processing wafer in the second embodiment. [Figure 27] FIG. 2 is a side view showing the outline of the configuration of the removal and separation device. [Figure 28] FIG. 10 is a flowchart showing main steps of wafer processing according to a third embodiment. [Figure 29] 10A to 10C are explanatory views of main steps of wafer processing according to a third embodiment. [Figure 30] FIG. 10 is a longitudinal sectional view showing an outline of the configuration of a transfer arm according to another embodiment. [Figure 31] FIG. 10 is a longitudinal cross-sectional view showing the outline of the configuration of the peripheral edge portion of an attraction plate according to another embodiment. [Figure 32] 10A and 10B are explanatory views showing a state in which a peripheral portion is removed in a transfer arm according to another embodiment. [Figure 33] FIG. 10 is a plan view showing the outline of the configuration of a reformer according to another embodiment. [Figure 34] 10A and 10B are explanatory views showing a state in which a peripheral modified layer is formed on a processing wafer in another embodiment. [Figure 35] 10A and 10B are explanatory views showing a state in which an internal surface modification layer is formed on a processing wafer in another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] In the manufacturing process of semiconductor devices, for example, as in the method disclosed in Patent Document 1, a semiconductor wafer (hereinafter referred to as "wafer") having a plurality of devices such as electronic circuits formed on its surface is subjected to a grinding process on the back surface of the wafer to thin the wafer.

[0010] Grinding the backside of a wafer is performed, for example, by rotating the wafer and grinding wheel while the grinding wheel is in contact with the backside and then lowering the grinding wheel. In this case, the grinding wheel wears out and needs to be replaced periodically. In addition, grinding water is used in the grinding process, and waste water treatment is also required. Therefore, conventional wafer thinning processes are expensive to run.

[0011] In addition, although the peripheral edge of a wafer is usually chamfered, when the backside of the wafer is ground as described above, the peripheral edge of the wafer becomes sharp (so-called knife-edge shape). This can cause chipping at the peripheral edge of the wafer, which can damage the wafer. Therefore, so-called edge trimming is performed to remove the peripheral edge of the wafer before grinding.

[0012] The edge grinding device described in Patent Document 2 mentioned above is a device that performs this edge trimming. However, since this edge grinding device performs edge trimming by grinding, the grinding wheel wears out and needs to be replaced periodically. In addition, a large amount of grinding water is used, and waste water treatment is also required. For this reason, conventional edge trimming has high running costs.

[0013] The technology disclosed herein efficiently performs pre-processing for wafer thinning and edge trimming. Hereinafter, a wafer processing system as a substrate processing apparatus and a wafer processing method as a substrate processing method according to this embodiment will be described with reference to the drawings. Note that in this specification and the drawings, elements having substantially the same functional configurations are designated by the same reference numerals, and redundant description will be omitted.

[0014] First, the configuration of the wafer processing system according to this embodiment will be described. Fig. 1 is a plan view showing a schematic outline of the configuration of the wafer processing system 1.

[0015] 2 and 3, the wafer processing system 1 performs a predetermined process on an overlapped wafer T, which is an overlapped substrate formed by bonding a process wafer W as a first substrate and a support wafer S as a second substrate. The wafer processing system 1 then removes a peripheral edge We of the process wafer W and further thins the process wafer W. Hereinafter, the surface of the process wafer W bonded to the support 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 support wafer S bonded to the process 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.

[0016] The processing wafer W is a semiconductor wafer such as a silicon wafer, and has a device layer (not shown) including multiple devices formed on its surface Wa. An oxide film F, such as an SiO2 film (TEOS film), is further formed on the device layer. The peripheral edge We of the processing wafer W is chamfered, and the cross section of the peripheral edge We becomes thinner toward its tip. The peripheral edge We is the portion removed during edge trimming, and is, for example, a range of 1 mm to 5 mm in the radial direction from the outer edge of the processing wafer W.

[0017] 2, in order to avoid complexity of the illustration, the oxide film F is omitted. Similarly, in other drawings used in the following description, the oxide film F may also be omitted.

[0018] The support wafer S is a wafer, such as a silicon wafer, that supports the process wafer W. An oxide film (not shown) is formed on the surface Sa of the support wafer S. The support wafer S also functions as a protective material that protects devices on the surface Wa of the process wafer W. If multiple devices are formed on the surface Sa of the support wafer S, a device layer (not shown) is formed on the surface Sa, similar to the surface of the process wafer W.

[0019] Here, if the processing wafer W and the support wafer S are bonded at the peripheral edge We of the processing wafer W, there is a risk that the peripheral edge We may not be properly removed. Therefore, at the interface between the processing wafer W and the support wafer S, a bonded region Aa where the oxide film F and the surface Sa of the support wafer S are bonded, and an unbonded region Ab, which is an area radially outward of the bonded region Aa, are formed. The presence of this unbonded region Ab allows the peripheral edge We to be properly removed. Note that, as will be described in detail later, it is preferable that the outer edge of the bonded region Aa be positioned slightly radially outward from the inner edge of the peripheral edge We to be removed.

[0020] 1, wafer processing system 1 has a configuration in which a load / unload station 2 and a processing station 3 are integrally connected. For example, a cassette Ct capable of accommodating a plurality of overlapped wafers T is loaded into and unloaded from the load / unload station 2 to the outside. Processing station 3 is equipped with various processing devices that perform predetermined processing on the overlapped wafers T.

[0021] The loading / unloading station 2 is provided with a cassette mounting table 10. In the illustrated example, a plurality of cassettes Ct, for example, three cassettes Ct, can be freely mounted on the cassette mounting table 10 in a line in the Y-axis direction. Note that the number of cassettes Ct mounted on the cassette mounting table 10 is not limited to that in this embodiment and can be determined arbitrarily.

[0022] In the carry-in / out station 2, a wafer transfer device 20 is provided adjacent to the cassette mounting table 10 on the negative side of the X-axis of the cassette mounting table 10. The wafer transfer device 20 is configured to be movable on a transfer path 21 extending in the Y-axis direction. The wafer transfer device 20 also has, for example, two transfer arms 22, 22 that hold and transfer the overlapped wafer T. Each transfer arm 22 is configured to be movable horizontally, vertically, around a horizontal axis, and around a vertical axis. The configuration of the transfer arm 22 is not limited to this embodiment and may have any configuration. The wafer transfer device 20 is also configured to be able to transfer the overlapped wafer T to the cassette Ct on the cassette mounting table 10 and to a transition device 30, which will be described later.

[0023] In the carry-in / out station 2, a transition device 30 for transferring the overlapped wafer T is provided adjacent to the wafer transfer device 20 on the negative side of the X axis of the wafer transfer device 20.

[0024] For example, three processing blocks G1 to G3 are provided in the processing station 3. The first processing block G1, the second processing block G2, and the third processing block G3 are arranged in this order from the positive side of the X-axis (the loading / unloading station 2 side) to the negative side.

[0025] The first processing block G1 is provided with an etching apparatus 40, a cleaning apparatus 41, and a wafer transfer apparatus 50. The etching apparatus 40 and the cleaning apparatus 41 are arranged in a stacked configuration. However, the number and arrangement of the etching apparatus 40 and the cleaning apparatus 41 are not limited to this. For example, the etching apparatus 40 and the cleaning apparatus 41 may each extend in the X-axis direction and be placed side by side in a plan view. Furthermore, the etching apparatus 40 and the cleaning apparatus 41 may each be stacked.

[0026] The etching apparatus 40 etches the back surface Wb of the processing wafer W ground by the processing apparatus 80 (described later). For example, a chemical solution (etchant) is supplied to the back surface Wb to wet-etch the back surface Wb. Examples of the chemical solution include HF, HNO, HPO, TMAH, choline, and KOH.

[0027] The cleaning device 41 cleans the back surface Wb of the processing wafer W ground by the processing device 80 described below. For example, a brush is brought into contact with the back surface Wb to scrub the back surface Wb. A pressurized cleaning liquid may be used to clean the back surface Wb. The cleaning device 41 may also be configured to clean the back surface Sb of the support wafer S as well as the back surface Wb of the processing wafer W.

[0028] The wafer transfer device 50 is disposed, for example, on the negative side of the Y axis relative to the etching device 40 and the cleaning device 41. The wafer transfer device 50 has, for example, two transfer arms 51, 51 that hold and transfer the overlapped wafer T. Each transfer arm 51 is configured to be movable horizontally, vertically, around a horizontal axis, and around a vertical axis. Note that the configuration of the transfer arm 51 is not limited to this embodiment and may have any configuration. The wafer transfer device 50 is configured to be able to transfer the overlapped wafer T to the transition device 30, the etching device 40, the cleaning device 41, and the modification device 60 described below.

[0029] The second processing block G2 is provided with a modifying device 60, an edge removing device 61, and a wafer transfer device 70. The modifying device 60 and the edge removing device 61 are arranged in a stacked configuration. Note that the number and arrangement of the modifying devices 60 and the edge removing devices 61 are not limited to this.

[0030] The modifying device 60 irradiates the inside of the processing wafer W with laser light to form a peripheral modified layer, divided modified layers, and an inner surface modified layer. The specific configuration of the modifying device 60 will be described later.

[0031] The peripheral edge removing device 61 removes the peripheral edge We of the processing wafer W, starting from the peripheral modified layer formed in the modifying device 60. The specific configuration of the peripheral edge removing device 61 will be described later.

[0032] The wafer transfer device 70 is disposed, for example, on the positive side of the Y axis relative to the modifying device 60 and the edge removing device 61. The wafer transfer device 70 has, for example, two transfer arms 71, 71 that hold and transfer the overlapped wafer T. Each transfer arm 71 is supported by an articulated arm member 72 and is configured to be movable horizontally, vertically, around a horizontal axis, and around a vertical axis. The specific configuration of the transfer arm 71 will be described later. The wafer transfer device 70 is configured to be able to transfer the overlapped wafer T to the cleaning device 41, the modifying device 60, the edge removing device 61, and a processing device 80, which will be described later.

[0033] The third processing block G3 is provided with a processing device 80. The number and arrangement of the processing devices 80 are not limited to those in this embodiment, and a plurality of processing devices 80 may be arranged arbitrarily.

[0034] The processing device 80 grinds the back surface Wb of the processing wafer W. Then, on the back surface Wb on which the internal surface modification layer is formed, the internal surface modification layer is removed, and further, the peripheral modification layer is removed. Specifically, the processing device 80 grinds the back surface Wb by rotating the processing wafer W and the grinding wheel (not shown) while the back surface Wb of the processing wafer W held by the chuck 81 is in contact with the grinding wheel. In this embodiment, the chuck 81 and the grinding wheel (not shown) constitute a processing unit. The processing device 80 uses a known grinding device (polishing device), such as the device described in JP 2010-69601 A.

[0035] The wafer processing system 1 described above is provided with a control device 90. The control device 90 is, for example, a computer, and has a program storage unit (not shown). The program storage unit stores a program for controlling the processing of the overlapped wafer T in the wafer processing system 1. The program storage unit also stores a program for controlling the operation of drive systems such as the various processing devices and transport devices described above to realize substrate processing, which will be described later, in the wafer processing system 1. The program may be recorded on a computer-readable storage medium H and installed into the control device 90 from the storage medium H.

[0036] Next, the above-mentioned reformer 60 will be described. Fig. 4 is a plan view showing the outline of the configuration of the reformer 60. Fig. 5 is a side view showing the outline of the configuration of the reformer 60.

[0037] The modification device 60 has a chuck 100 as a substrate holder that holds the overlapped wafer T on its upper surface. The chuck 100 suction-holds the support wafer S with the process wafer W on top and the support wafer S on the bottom. The chuck 100 is supported by a slider table 102 via an air bearing 101. A rotating unit 103 is provided on the underside of the slider table 102. The rotating unit 103 incorporates, for example, a motor as a drive source. The chuck 100 is configured to be rotatable about a vertical axis by the rotating unit 103 via the air bearing 101. The slider table 102 is configured to be movable along a rail 105 that is provided on a base 106 and extends in the Y-axis direction by a horizontal moving unit 104 provided on its underside. The drive source of the horizontal moving unit 104 is not particularly limited, but a linear motor, for example, is used.

[0038] A laser head 110 is provided above the chuck 100. The laser head 110 has a lens 111. The lens 111 is a cylindrical member provided on the lower surface of the laser head 110, and irradiates the processing wafer W held by the chuck 100 with laser light. In this embodiment, the peripheral modification unit and the internal surface modification unit have a common laser head 110.

[0039] The laser head 110 also includes an LCOS (Liquid Crystal on Silicon) (not shown). The LCOS is a spatial light modulator that modulates and outputs laser light. Specifically, the LCOS can control the focal position and phase of the laser light, and can adjust the shape and number (number of branches) of the laser light irradiated onto the processing wafer W.

[0040] The laser head 110 focuses and irradiates a high-frequency pulsed laser beam oscillated from a laser beam oscillator (not shown) at a predetermined position inside the processing wafer W, the laser beam having a wavelength that is transparent to the processing wafer W. As a result, the portion inside the processing wafer W where the laser beam is focused is modified, and a peripheral modified layer, a divided modified layer, and an internal surface modified layer are formed.

[0041] The laser head 110 is supported by a support member 120. The laser head 110 is configured to be able to move up and down by an elevating mechanism 130 along rails 121 extending in the vertical direction. The laser head 110 is also configured to be able to move in the Y-axis direction by a moving mechanism 131. The elevating mechanism 130 and the moving mechanism 131 are each supported by a support column 132.

[0042] Macro camera 140 and micro camera 150 are provided above chuck 100, on the Y-axis positive side of laser head 110. For example, macro camera 140 and micro camera 150 are configured as an integrated unit, with macro camera 140 being disposed on the Y-axis positive side of micro camera 150. Macro camera 140 and micro camera 150 are configured to be able to move up and down freely by elevator mechanism 160, and further configured to be able to move freely in the Y-axis direction by movement mechanism 161.

[0043] The macro camera 140 captures an image of the outer edge of the processing wafer W (polymerized wafer T). The macro camera 140 is equipped with, for example, a coaxial lens, irradiates visible light, for example, red light, and receives reflected light from an object. For example, the imaging magnification of the macro camera 140 is 2x.

[0044] The micro camera 150 captures an image of the peripheral portion of the processing wafer W, capturing an image of the boundary between the bonded region Aa and the unbonded region Ab. The micro camera 150 is equipped with, for example, a coaxial lens, irradiates infrared light (IR light), and receives reflected light from an object. For example, the imaging magnification of the micro camera 150 is 10 times, the field of view is approximately 1 / 5 of that of the macro camera 140, and the pixel size is approximately 1 / 5 of that of the macro camera 140.

[0045] Next, the above-mentioned peripheral edge removing device 61 will be described. Fig. 6 is a plan view showing an outline of the configuration of the peripheral edge removing device 61. Fig. 7 is a side view showing an outline of the configuration of the peripheral edge removing device 61.

[0046] The edge removal device 61 has a chuck 170 as another substrate holding unit that holds the overlapped wafer T on its upper surface. The chuck 170 suction-holds the support wafer S with the process wafer W on the upper side and the support wafer S on the lower side. The chuck 170 is configured to be rotatable around a vertical axis by a rotation mechanism 171.

[0047] A pad 180 serving as a peripheral edge removal unit that holds and transfers the peripheral edge We of the processing wafer W is provided above the chuck 170. A suction mechanism (not shown), such as a vacuum pump, is connected to the pad 180, and the pad 180 holds the peripheral edge We by suction on its underside. The pad 180 is provided with an elevating mechanism 181 that raises and lowers the pad 180 in the vertical direction, and a moving mechanism 182 that moves the pad 180 in the horizontal direction (X-axis direction and Y-axis direction).

[0048] A detection unit 190 is provided above the chuck 170 to check whether the peripheral edge We has been removed from the processing wafer W. The detection unit 190 detects the presence or absence of the peripheral edge We in the processing wafer W held by the chuck 170 and from which the peripheral edge We has been removed. The detection unit 190 may use, for example, a sensor. The sensor may be, for example, a line-type laser displacement meter, and detects the presence or absence of the peripheral edge We by irradiating the peripheral edge of the overlapped wafer T (processing wafer W) with a laser and measuring the thickness of the overlapped wafer T. Note that the method of detecting the presence or absence of the peripheral edge We by the detection unit 190 is not limited to this. For example, the detection unit 190 may use, for example, a line camera to capture an image of the overlapped wafer T (processing wafer W) to detect the presence or absence of the peripheral edge We.

[0049] A recovery unit (not shown) that recovers the peripheral edge We transferred by the pad 180 is provided below the chuck 170. The recovery unit receives and recovers the peripheral edge We that is sucked and held by the pad 180.

[0050] Next, a description will be given of the transfer arm 71 of the above-mentioned wafer transfer device 70. FIG.

[0051] The transfer arm 71, which serves as a substrate separating unit and a transfer unit, has a disk-shaped suction plate 200 having a diameter larger than the overlapped wafer T. A holder 210 for holding the central portion Wc of the processing wafer W is provided on the lower surface of the suction plate 200.

[0052] A suction pipe 211 that sucks the central portion Wc is connected to the holding portion 210, and the suction pipe 211 is in communication with a suction mechanism 212 such as a vacuum pump. A pressure sensor 213 that measures the suction pressure is provided on the suction pipe 211. The pressure sensor 213 may have any configuration, but may be, for example, a diaphragm-type pressure gauge.

[0053] A rotation mechanism 220 that rotates the attraction plate 200 around a vertical axis is provided on the upper surface of the attraction plate 200. The rotation mechanism 220 is supported by a support member 221. In addition, the support member 221 (rotation mechanism 220) is supported by an arm member 72.

[0054] Next, a description will be given of wafer processing according to a first embodiment, which is performed using the wafer processing system 1 configured as described above. Fig. 9 is a flow diagram showing the main steps of the wafer processing. Fig. 10 is an explanatory diagram of the main steps of the wafer processing. In this embodiment, the processing wafer W and the support wafer S are bonded together in a bonding device (not shown) external to the wafer processing system 1 to form an overlapping wafer T in advance.

[0055] First, a cassette Ct containing a plurality of overlapping wafers T shown in FIG. 10( a ) is placed on the cassette placement table 10 of the carry-in / out station 2 .

[0056] Next, the wafer transfer device 20 removes the overlapped wafer T from the cassette Ct and transfers it to the transition device 30. Subsequently, the wafer transfer device 50 removes the overlapped wafer T from the transition device 30 and transfers it to the modification device 60. In the modification device 60, a peripheral modified layer M1 and a divided modified layer M2 are sequentially formed inside the processing wafer W as shown in FIG. 10(b) (steps A1 and A2 in FIG. 9), and then an internal surface modified layer M3 is formed as shown in FIG. 10(c) (step A3 in FIG. 9). The peripheral modified layer M1 serves as a base point for removing the peripheral portion We during edge trimming. The divided modified layer M2 serves as a base point for dividing the peripheral portion We to be removed into small pieces. The internal surface modified layer M3 serves as a base point for thinning the processing wafer W.

[0057] 11A and 11B are explanatory diagrams of the main steps of the modification process in the modification device 60. First, as shown in FIG. 11A, the chuck 100 (slider table 102) is moved to the transfer position P1. Then, the overlapped wafer T is transferred from the wafer transfer device 50 and held by the chuck 100.

[0058] 11(b), the chuck 100 is moved to the macro alignment position P2, which is a position where the macro camera 140 can capture an image of the outer edge of the processing wafer W.

[0059] Next, the macro camera 140 captures images of the outer edge of the processing wafer W in the 360-degree circumferential direction. The captured images are output from the macro camera 140 to the control device 90.

[0060] The control device 90 calculates a first eccentricity between the center Cc of the chuck 100 and the center Cw of the processing wafer W from the image of the macro camera 140. Furthermore, the control device 90 calculates a movement amount of the chuck 100 based on the first eccentricity so as to correct the Y-axis component of the first eccentricity. The chuck 100 moves in the Y-axis direction based on this calculated movement amount, and moves the chuck 100 to the micro-alignment position P3 as shown in FIG. 11(c). The micro-alignment position P3 is a position where the micro-camera 150 can capture an image of the peripheral portion of the processing wafer W. Here, as described above, the field of view of the micro-camera 150 is approximately 1 / 5 that of the macro camera 140. Therefore, if the Y-axis component of the first eccentricity is not corrected, the peripheral portion of the processing wafer W may not fall within the field of view of the micro-camera 150, and may not be captured by the micro-camera 150. Therefore, it can be said that the correction of the Y-axis component based on the first eccentricity amount is for moving the chuck 100 to the micro-alignment position P3.

[0061] Next, the micro camera 150 captures an image of the boundary between the bonded region Aa and the unbonded region Ab in the 360-degree circumferential direction of the processing wafer W. The captured image is output from the micro camera 150 to the control device 90.

[0062] The control device 90 calculates a second eccentricity between the center Cc of the chuck 100 and the center Ca of the bonding region Aa from the image captured by the micro camera 150. Furthermore, the control device 90 determines the position of the chuck 100 relative to the peripheral modified layer M1 based on the second eccentricity so that the center of the bonding region Aa coincides with the center of the chuck 100. As described above, an unbonded region Ab is formed before bonding the process wafer W and the support wafer S. However, the center of this unbonded region Ab (the center Ca of the bonding region Aa) may be misaligned with the center of the process wafer W. In this regard, the misalignment of the unbonded region Ab is corrected by adjusting the position of the chuck 100 relative to the peripheral modified layer M1 based on the second eccentricity, as in the present embodiment.

[0063] 11(d), the chuck 100 is moved to the modification position P4. The modification position P4 is a position where the laser head 110 irradiates the processing wafer W with laser light to form a peripheral modified layer M1. In this embodiment, the modification position P4 is the same as the micro-alignment position P3.

[0064] Next, as shown in FIGS. 12 and 13, a laser beam L1 (periphery laser beam L1) is emitted from the laser head 110 to form a peripheral modified layer M1 at the boundary between the peripheral portion We and the central portion Wc of the processing wafer W (step A1 in FIG. 9). The shape and number of the laser beam L1 are adjusted by the LCOS. Specifically, the focal position and phase of the laser beam L1 are controlled to adjust the shape so as to form the peripheral modified layer M1, which will be described later. In this embodiment, the number of laser beams L1 is one.

[0065] The peripheral modified layer M1 formed by the laser beam L1 extends in the thickness direction and has a vertically elongated aspect ratio. The lower end of the peripheral modified layer M1 is located above the target surface (dotted line in FIG. 12) of the processed wafer W after thinning. That is, the distance H1 between the lower end of the peripheral modified layer M1 and the front surface Wa of the processed wafer W is greater than the target thickness H2 of the processed wafer W after thinning. In this case, the peripheral modified layer M1 does not remain on the processed wafer W after thinning. Note that, inside the processed wafer W, cracks C1 propagate from the peripheral modified layer M1 and reach the front surface Wa and back surface Wb.

[0066] The peripheral modified layer M1 is formed radially inward from the outer edge of the bonding region Aa. When forming the peripheral modified layer M1 with the laser light L1 from the laser head 110, even if the peripheral modified layer M1 is formed offset from the outer edge of the bonding region Aa due to, for example, a processing error, the peripheral modified layer M1 can be prevented from being formed radially outward from the outer edge of the bonding region Aa. If the peripheral modified layer M1 is formed radially outward from the outer edge of the bonding region Aa, the processing wafer W will be floating relative to the support wafer S after the peripheral portion We is removed. In this regard, the present embodiment can reliably prevent such a state of the processing wafer W.

[0067] Furthermore, through careful investigation, the inventors have confirmed that the peripheral portion We can be appropriately removed if the distance D between the peripheral modification layer M1 and the outer edge of the bonding region Aa is sufficiently small. This distance D is preferably within 500 μm, and more preferably within 50 μm.

[0068] Here, as described above, the control device 90 determines the position of the chuck 100 based on the second eccentricity amount. In step A1, in accordance with the determined position of the chuck 100, the rotation unit 103 rotates the chuck 100 and the horizontal movement unit 104 moves the chuck 100 in the Y-axis direction so that the center of the joining area Aa coincides with the center of the chuck 100. At this time, the rotation of the chuck 100 and the movement in the Y-axis direction are synchronized. By performing this complete synchronization control, the movement of the chuck 100 can be made to properly follow the determined position with little error.

[0069] Then, while rotating and moving the chuck 100 (processing wafer W) in this manner, the laser head 110 irradiates the inside of the processing wafer W with laser light L1. That is, the peripheral modified layer M1 is formed while correcting the second eccentricity. In this way, the peripheral modified layer M1 is formed in an annular shape concentric with the bonding area Aa. That is, the distance D between the peripheral modified layer M1 and the outer edge of the bonding area Aa shown in FIG. 12 can be made constant. Therefore, in the subsequent peripheral removal device 61, the peripheral portion We can be appropriately removed using the peripheral modified layer M1 as a base point.

[0070] In this example, when the second eccentricity amount has an X-axis component, the X-axis component is corrected by rotating the chuck 100 while moving the chuck 100 in the Y-axis direction. On the other hand, when the second eccentricity amount does not have an X-axis component, it is sufficient to simply move the chuck 100 in the Y-axis direction without rotating it.

[0071] Next, the laser head 110 is moved in the Y-axis direction, and as shown in FIGS. 14 and 15, laser light L2 (division laser light L2) is irradiated from the laser head 110 to form divided modified layers M2 radially outside the peripheral modified layer M1 (step A2 in FIG. 9). At this time, the laser light irradiated from the laser head 110 is switched from laser light L1 to laser light L2 by the LCOS, and the shape and number of the laser light L2 are adjusted. Specifically, the focal position and phase of the laser light L2 are controlled to adjust the shape so as to form divided modified layers M2, which will be described later. In this embodiment, the number of laser light L2 is one.

[0072] Like the peripheral modified layer M1, the divided modified layer M2 also extends in the thickness direction and has a vertically elongated aspect ratio. In this embodiment, the divided modified layer M2 is formed to the same height as the peripheral modified layer M1. In addition, cracks C2 propagate from the divided modified layer M2 and reach the front surface Wa and back surface Wb.

[0073] Furthermore, by forming multiple divided modified layers M2 and cracks C2 at a pitch of several μm in the radial direction, a single line of divided modified layers M2 is formed extending radially outward from the peripheral modified layer M1, as shown in FIG. 15. In the illustrated example, the divided modified layers M2 extending radially in a line are formed in eight locations, but the number of divided modified layers M2 is arbitrary. If the divided modified layers M2 are formed in at least two locations, the peripheral portion We can be removed. In this case, when removing the peripheral portion We during edge trimming, the peripheral portion We is divided into multiple pieces by the divided modified layers M2, while being separated using the annular peripheral modified layer M1 as a base point. This breaks down the peripheral portion We to be removed into small pieces, making it easier to remove.

[0074] In this embodiment, the laser head 110 is moved in the Y-axis direction when forming the divided modified layers M2, but the chuck 100 may be moved in the Y-axis direction.

[0075] Next, as shown in FIGS. 16 and 17, laser light L3 (laser light L3 for the internal surface) is irradiated from the laser head 110 to form an internal surface modified layer M3 along the surface direction (step A3 in FIG. 9). At this time, the laser light irradiated from the laser head 110 is switched from laser light L2 to laser light L3 by the LCOS, and the shape and number of laser light L3 are adjusted. Specifically, the focal position and phase of laser light L3 are controlled to adjust the shape so as to form the internal surface modified layer M3 described below. In this embodiment, the number of laser light L3 is one. Note that the black arrow in FIG. 17 indicates the rotation direction of the chuck 100, and this also applies to the following explanation.

[0076] The lower end of the internal surface modification layer M3 is located slightly above the target surface (dotted line in FIG. 16) of the processed wafer W after thinning. That is, the distance H3 between the lower end of the internal surface modification layer M3 and the surface Wa of the processed wafer W is slightly larger than the target thickness H2 of the processed wafer W after thinning. Note that, inside the processed wafer W, cracks C3 propagate from the internal surface modification layer M3 in the surface direction.

[0077] In step A3, the chuck 100 (processing wafer W) is rotated, and the laser head 110 is moved in the Y-axis direction from the outer periphery to the center of the processing wafer W, while irradiating the interior of the processing wafer W with laser light L3 from the laser head 110. As a result, an internal surface modification layer M3 is formed in a spiral shape from the outside to the inside within the surface of the processing wafer W.

[0078] In this embodiment, the laser head 110 is moved in the Y-axis direction when forming the inner surface modified layer M3, but the chuck 100 may be moved in the Y-axis direction.

[0079] 11(e), the chuck 100 is moved to the transfer position P1, and the overlapped wafer T is then transferred by the wafer transfer device .

[0080] As described above, in the modification apparatus 60, the peripheral modified layer M1 in step A1 and the internal surface modified layer M3 in step A3 are formed in this order. If the internal surface modified layer M3 were formed before the peripheral modified layer M1, the processing wafer W might expand or warp. For example, when the internal surface modified layer M3 is formed, cracks C3 are formed in the surface direction of the processing wafer W. Stress is then applied to the cracks C3, causing the processing wafer W to expand in the surface direction. Furthermore, if the magnitude of this expansion varies depending on the surface direction of the processing wafer W, localized separation of the processing wafer W may occur. In such a case, the height of the processing wafer W becomes non-uniform within the surface, causing warpage. If the processing wafer W expands or warps in this way, the peripheral modified layer M1 cannot be formed in the appropriate position. As a result, the peripheral portion We cannot be properly removed, and quality cannot be ensured. In this regard, in this embodiment, the peripheral modified layer M1 and the internal surface modified layer M3 are formed in this order, thereby suppressing expansion and warpage of the processing wafer W.

[0081] Next, the overlapped wafer T is transported by the wafer transport device 70 to the edge removal device 61. In the edge removal device 61, the edge We of the processing wafer W is removed using the edge modified layer M1 as a base point, as shown in FIG. 10(d) (step A4 in FIG. 9). In step A4, as shown in FIG. 18, the lifting mechanism 181 lowers the pad 180 to suction-hold the edge We, and then the pad 180 is further raised. As a result, the edge We held by the pad 180 is separated from the processing wafer W using the edge modified layer M1 as a base point. At this time, the edge We is separated into small pieces using the divided modified layer M2 as a base point. The removed edge We is then recovered from the pad 180 to a recovery unit (not shown).

[0082] Next, the overlapped wafer T is transferred to the processing device 80 by the wafer transfer device 70. In the processing device 80, first, when the overlapped wafer T is transferred from the transfer arm 71 to the chuck 81, the back surface Wb side of the processing wafer W (hereinafter referred to as the back surface wafer Wb1) is separated from the inner surface modification layer M3 as a base point, as shown in FIG. 10(e) (step A5 in FIG. 9).

[0083] In step A5, as shown in FIG. 19(a), the suction plate 200 of the transfer arm 71 suction-holds the processing wafer W, while the chuck 81 suction-holds the support wafer S. Then, the suction plate 200 is rotated to separate the backside wafer Wb1 at the inner surface modification layer M3. Thereafter, as shown in FIG. 19(b), while the suction plate 200 suction-holds the backside wafer Wb1, the suction plate 200 is raised to separate the backside wafer Wb1 from the processing wafer W. At this time, the pressure sensor 213 measures the pressure applied to the backside wafer Wb1 to detect the presence or absence of the backside wafer Wb1, thereby confirming whether the backside wafer Wb1 has been separated from the processing wafer W. Note that if the backside wafer Wb1 can be separated simply by raising the suction plate 200 as shown in FIG. 19(b), the rotation of the suction plate 200 shown in FIG. 19(a) may be omitted. The separated backside wafer Wb1 is then collected outside the wafer processing system 1.

[0084] 10(f), the back surface Wb of the processing wafer W held by the chuck 81 is ground to remove the inner surface modified layer M3 and the peripheral modified layer M1 remaining on the back surface Wb (step A6 in FIG. 9). In step A6, the processing wafer W and the grinding wheel are rotated while the grinding wheel is in contact with the back surface Wb to grind the back surface Wb. Thereafter, the back surface Wb of the processing wafer W may be cleaned with a cleaning liquid using a cleaning liquid nozzle (not shown).

[0085] Next, the overlapped wafer T is transferred by the wafer transfer device 70 to the cleaning device 41. In the cleaning device 41, the back surface Wb, which is the ground surface of the processing wafer W, is scrubbed (step A7 in FIG. 9). Note that in the cleaning device 41, the back surface Sb of the support wafer S may also be cleaned together with the back surface Wb of the processing wafer W.

[0086] Next, the overlapped wafer T is transported by the wafer transport device 50 to the etching device 40. In the etching device 40, the back surface Wb of the processing wafer W is wet-etched with a chemical solution (step A8 in FIG. 9). Grinding marks may be formed on the back surface Wb that has been ground by the processing device 80 described above. In this step A8, the grinding marks can be removed by wet etching, and the back surface Wb can be smoothed.

[0087] Thereafter, the overlapped wafer T that has undergone all the processing is transferred by the wafer transfer device 50 to the transition device 30, and further transferred by the wafer transfer device 20 to the cassette Ct on the cassette mounting table 10. In this way, the series of wafer processing steps in the wafer processing system 1 is completed.

[0088] According to the above embodiment, edge trimming is performed by removing the peripheral portion We starting from the peripheral modified layer M1, and then the backside wafer Wb1 is separated starting from the inner surface modified layer M3 to thin the processing wafer W. The laser head 110 used to form the peripheral modified layer M1 and the inner surface modified layer M3 is less likely to deteriorate over time, and fewer consumables are required, reducing the frequency of maintenance. Furthermore, because this is a dry process using a laser, grinding water and wastewater treatment are not required. This reduces running costs. Therefore, running costs can be reduced compared to conventional edge trimming by grinding or thinning by grinding.

[0089] In this embodiment, the back surface Wb is ground in step A6. This grinding only removes the inner surface modified layer M3 and the peripheral modified layer M1, and the amount of grinding is small, on the order of several tens of μm. In contrast, when the back surface Wb is ground to thin the processing wafer W as in the past, the amount of grinding is large, for example, 700 μm or more, and the degree of wear of the grinding stone is large. Therefore, in this embodiment, the maintenance frequency can also be reduced.

[0090] Furthermore, according to this embodiment, the peripheral modified layer M1 and the inner surface modified layer M3 are formed in this order inside the processing wafer W. As described above, if the inner surface modified layer M3 is formed first, the processing wafer W may expand or warp, but this embodiment can suppress this expansion and warp of the processing wafer W. As a result, the peripheral portion We can be appropriately removed, ensuring quality.

[0091] Furthermore, according to this embodiment, by adjusting the shapes of the laser beams L1 to L3 using a single laser head 110, it is possible to form the peripheral modified layer M1, the divided modified layer M2, and the internal surface modified layer M3. That is, even when the extension direction of the modified layer or the required processing quality differs, it is possible to select an appropriate shape of the laser beam using a single laser head 110. Since modified layers of any shape can be formed in this way, the degree of freedom in forming the modified layer is improved. Furthermore, the occupied area (footprint) of the apparatus can be reduced, thereby realizing space saving. Furthermore, since the apparatus configuration is simplified, it is also possible to reduce the apparatus cost. As described above, in this embodiment, the thinning process and edge trim preprocessing of the processing wafer W can be efficiently performed.

[0092] In the above embodiment, one laser head 110 irradiates laser beams L1 to L3 of different shapes. However, it is preferable that the laser head 110 be calibrated before the overlapped wafer T to be processed is loaded into the modifying apparatus 60. More specifically, it is preferable that the laser head 110 be calibrated before the overlapped wafer T is held by the chuck 100. In this case, it is not necessary to calibrate the laser head 110 during the modification process for one processing wafer W, and the time required to switch between the laser beams L1 to L3 can be shortened. As a result, the throughput of wafer processing can be improved.

[0093] Furthermore, in the above embodiment, when forming the peripheral modified layer M1, one laser beam L1 is irradiated from the laser head 110 onto the inside of the processing wafer W, but multiple laser beams L1 may be irradiated. In such a case, the time required to form the peripheral modified layer M1 can be shortened, and the throughput of wafer processing can be further improved. Similarly, when forming the inner surface modified layer M3, one laser beam L3 is irradiated from the laser head 110 onto the inside of the processing wafer W, but multiple laser beams L3 may be irradiated. In such a case, the time required to form the inner surface modified layer M3 can also be shortened, and the throughput of wafer processing can be further improved.

[0094] In the above embodiment, the peripheral edge We is removed using the pad 180 in the peripheral edge removal device 61, and the processing wafer W is separated using the transfer arm 71 in the processing device 80. However, the removal of the peripheral edge We and the transfer arm 71 may be performed within the same device. For example, as shown in FIG. 20 , the peripheral edge removal device 61 further includes an adsorption plate 230 as a substrate separation unit above the chuck 170. The adsorption plate 230 has a configuration similar to that of the adsorption plate 200 of the transfer arm 71 and has a circular plate shape with a diameter larger than that of the overlapped wafer T. A suction mechanism (not shown), such as a vacuum pump, is connected to the adsorption plate 230, and the adsorption plate 230 adsorbs and holds the back surface Wb of the processing wafer W on its lower surface. The adsorption plate 230 is provided with an elevation mechanism 231 that raises and lowers the adsorption plate 230 in the vertical direction, and a rotation mechanism 232 that rotates the adsorption plate 230 about a vertical axis.

[0095] In this case, after removing the peripheral edge portion We with the pad 180 in step A4, the processing wafer W is separated with the suction plate 230 in step A5. In step A5, the back surface Wb of the processing wafer W is suction-held by the suction plate 230. Then, the suction plate 230 is rotated to separate the back surface wafer Wb1 at the inner surface modification layer M3. Thereafter, with the suction plate 230 suction-holding the back surface wafer Wb1, the suction plate 230 is raised to separate the back surface wafer Wb1 from the processing wafer W. Note that if the back surface wafer Wb1 can be separated simply by raising the suction plate 230, the rotation of the suction plate 230 may be omitted.

[0096] The suction plate 230 may separately suction-hold the central portion Wc and the peripheral portion We of the processing wafer W. Specifically, for example, a central holding portion (not shown) for holding the central portion Wc and a peripheral holding portion (not shown) for holding the peripheral portion We may be provided on the lower surface of the suction plate 230. Separate suction mechanisms (not shown) are connected to the central holding portion and the peripheral holding portion, respectively, and the central holding portion and the peripheral holding portion can be switched to suction-hold the central portion Wc and the peripheral portion We separately. In such a case, the removal of the peripheral portion We in step A4 and the separation of the processing wafer W in step A5 are each performed by the suction plate 230. In this example, the pad 180, the lifting mechanism 181, and the moving mechanism 182 are omitted.

[0097] In this embodiment, too, it is possible to appropriately remove the peripheral edge We of the processing wafer W and separate the processing wafer W. Moreover, since these operations can be performed in the same apparatus, it is possible to improve the throughput of wafer processing.

[0098] In this embodiment, the peripheral modified layer M1 and the inner surface modified layer M3 are formed in this order inside the processing wafer W. However, when the inner surface modified layer M3 is formed, the processing wafer W may expand. In such a case, the peripheral portion We may peel off due to the expansion of the processing wafer W, and the peeled peripheral portion We may adversely affect the drive system, such as the rotating unit 103 and the horizontal moving unit 104, inside the modifying device 60. Therefore, it is preferable to take measures to prevent the peripheral portion We from peeling off. For example, the following two measures can be considered as countermeasures.

[0099] The first measure to prevent peeling of the peripheral edge portion We is to physically hold down the peripheral edge portion We. For example, as shown in FIG. 21, multiple cylindrical peripheral edge holders 240 that contact the outer edge of the processing wafer W may be provided. Alternatively, as shown in FIG. 22, multiple rectangular parallelepiped peripheral edge holders 241 that contact the outer edge of the processing wafer W may be provided. Each of these peripheral edge holders 240, 241 is configured to be movable vertically and horizontally by a movement mechanism (not shown). The peripheral edge holders 240, 241 may make point or line contact with the processing wafer W, but either method can prevent peeling of the peripheral edge portion We. Note that the peripheral edge holders 240, 241 only need to contact the outer edge of the processing wafer W when forming the inner surface modification layer M3, and may be retracted from the processing wafer W at other times.

[0100] The second measure to prevent peeling of the peripheral portion We is to propagate cracks C1 formed from the peripheral modified layer M1 in the thickness direction of the processing wafer W only to the front surface Wa. By adjusting the shape of the laser light L1 irradiated from the laser head 110, the cracks C1 are propagated only to the front surface Wa, as shown in FIG. 23(a), and do not reach the back surface Wb. Similarly, when forming the divided modified layer M2, the cracks C2 are propagated only to the front surface Wa, and do not reach the back surface Wb. In this case, even if an internal surface modified layer M3 is subsequently formed, as shown in FIG. 23(b), the peripheral portion We will not peel off from the processing wafer W.

[0101] Next, wafer processing according to the second embodiment will be described. Fig. 24 is a flow diagram showing the main steps of the wafer processing. Fig. 25 is an explanatory diagram of the main steps of the wafer processing.

[0102] In the first embodiment, removal of the peripheral edge We and separation of the processing wafer W are performed separately, but in the second embodiment, these are performed simultaneously. Removal of the peripheral edge We and separation of the processing wafer W are performed, for example, in the processing apparatus 80 using a transfer arm 71 as a removal / separation unit. Note that the transfer arm 71 in this embodiment holds the entire processing wafer W, i.e., the central portion Wc and the peripheral edge We. Furthermore, because removal of the peripheral edge We is performed using the transfer arm 71 in this manner, the peripheral edge removal device 61 may be omitted in the wafer processing system 1 of this embodiment.

[0103] In wafer processing according to the second embodiment, first, the overlapped wafer T shown in Fig. 25(a) is transferred to the modifying apparatus 60. In the modifying apparatus 60, a peripheral modified layer M10 (step B1 in Fig. 24) is formed on the processing wafer W as shown in Fig. 25(b), and further, an inner surface modified layer M30 (step B2 in Fig. 24) is formed as shown in Fig. 25(c).

[0104] Here, the method for forming the peripheral modified layer M10 in step B1 is the same as step A1, except that, whereas the crack C1 in the peripheral modified layer M1 shown in Figure 10(b) propagates to the front surface Wa and the back surface Wb, the crack C10 from the peripheral modified layer M10 propagates only to the front surface Wa and does not reach the back surface Wb.

[0105] The method for forming the inner surface modified layer M30 in step B2 is the same as that in step A3, except that, whereas the crack C3 in the inner surface modified layer M3 shown in Fig. 10(c) propagates in the surface direction to the outer edge of the processed wafer W, the crack C30 from the inner surface modified layer M30 propagates only inside the peripheral modified layer M10.

[0106] Next, the overlapped wafer T is transported to the processing device 80 by the wafer transport device 70. In the processing device 80, first, when the overlapped wafer T is transferred from the transport arm 71 to the chuck 81, the back surface Wb side of the processing wafer W (hereinafter referred to as the back surface wafer Wb2) is separated using the peripheral modified layer M10 and the inner surface modified layer M30 as base points, as shown in FIG. 25(d) (step B3 in FIG. 24).

[0107] In step B3, as shown in FIG. 26(a), the suction plate 200 of the transfer arm 71 suction-holds the processing wafer W, while the chuck 81 suction-holds the support wafer S. Then, the suction plate 200 is rotated to separate the back surface wafer Wb2 at the boundary between the peripheral modified layer M10 and the inner surface modified layer M30. Thereafter, as shown in FIG. 26(b), while the suction plate 200 suction-holds the back surface wafer Wb2, the suction plate 200 is raised to separate the back surface wafer Wb2 from the processing wafer W. In this way, in step B3, the back surface wafer Wb2 is separated together with the peripheral edge We; that is, removal of the peripheral edge We and separation of the processing wafer W are performed simultaneously.

[0108] 25(e), the back surface Wb of the processing wafer W is ground (step B4 in FIG. 24), followed by cleaning of the back surface Wb in the cleaning apparatus 41 (step B5 in FIG. 24) and wet etching of the back surface Wb in the etching apparatus 40 (step B6 in FIG. 24). In this way, a series of wafer processing steps in the wafer processing system 1 is completed.

[0109] In this embodiment, a peripheral modified layer M10 and an internal surface modified layer M30 are formed in this order inside the processing wafer W, and the same effects as those of the first embodiment can be obtained. Moreover, because cracks from the peripheral modified layer M10 do not reach the back surface Wb, the peripheral portion We is not peeled off due to expansion of the processing wafer W when the internal surface modified layer M30 is formed. Note that to more reliably prevent peeling of the peripheral portion We, peripheral holders 240 and 241 may be provided as shown in FIG. 21 or 22.

[0110] In the above embodiment, removal of the peripheral edge We and separation of the processing wafer W are performed using the transfer arm 71, but these may be performed using a separate device. For example, the wafer processing system 1 may be provided with a removal / separation device 300 shown in FIG. 27 instead of the peripheral edge removal device 61.

[0111] The removal / separation device 300 has a chuck 310 as another substrate holder that holds the overlapped wafer T on its upper surface. The chuck 310 suction-holds the support wafer S with the process wafer W on the upper side and the support wafer S on the lower side. The chuck 310 is configured to be rotatable around a vertical axis by a rotation mechanism 311.

[0112] Above the chuck 310, an adsorption plate 320 is provided as a removal / separation unit. The adsorption plate 320 has a configuration similar to that of the adsorption plate 200 of the transfer arm 71, and has a circular plate shape with a diameter larger than that of the overlapped wafer T. A suction mechanism (not shown), such as a vacuum pump, is connected to the adsorption plate 320, and the lower surface of the adsorption plate 320 adsorbs and holds the back surface Wb of the processing wafer W. The adsorption plate 320 is provided with an elevation mechanism 321 that raises and lowers the adsorption plate 320 in the vertical direction, and a rotation mechanism 322 that rotates the adsorption plate 320 around a vertical axis.

[0113] In this case, the back surface Wb of the processing wafer W is suction-held by the suction plate 320. Then, the suction plate 320 is rotated to separate the back surface wafer Wb2 at the boundary between the peripheral modified layer M10 and the inner surface modified layer M30. Thereafter, while the suction plate 320 suction-holds the back surface wafer Wb2, the suction plate 320 is raised to separate the back surface wafer Wb2 from the processing wafer W. The removal / separation apparatus 300 of this embodiment can also appropriately remove the peripheral portion We of the processing wafer W and separate the processing wafer W.

[0114] Next, wafer processing according to the third embodiment will be described. Fig. 28 is a flow chart showing the main steps of the wafer processing. Fig. 29 is an explanatory diagram of the main steps of the wafer processing.

[0115] In the first embodiment, the peripheral edge We is removed after the internal surface modification layer M3 is formed. However, in the third embodiment, the peripheral edge We is removed before the internal surface modification layer M31 is formed. That is, in the third embodiment, the peripheral edge We is removed, and then the internal surface modification layer M31 is formed. The peripheral edge modification layer M11 and the internal surface modification layer M31 are formed in the modification apparatus 60, respectively. However, if the peripheral edge We is removed outside the modification apparatus 60, throughput will decrease. Therefore, in this embodiment, the peripheral edge We is removed inside the modification apparatus 60 using a transfer arm 71 as a peripheral edge removal unit. Because the peripheral edge We is removed using the transfer arm 71 in this manner, the peripheral edge removal unit 61 may be omitted in the wafer processing system 1 of this embodiment. The transfer arm 71 also functions as a substrate separation unit, as described below.

[0116] 30 , the transfer arm 71 has a disk-shaped suction plate 400 having a diameter larger than the diameter of the processing wafer W. The lower surface of the suction plate 400 is provided with a center holding portion 410 that holds the center portion Wc of the processing wafer W, and a peripheral holding portion 420 that holds the peripheral portion We of the processing wafer W.

[0117] A suction pipe 411 that sucks the central portion Wc is connected to the central holding portion 410, and the suction pipe 411 is in communication with a central suction mechanism 412 such as a vacuum pump. A central pressure sensor 413 that measures the suction pressure is provided on the suction pipe 411. The central pressure sensor 413 may have any configuration, but may be, for example, a diaphragm-type pressure gauge.

[0118] A suction pipe 421 that sucks the peripheral edge We is connected to the peripheral edge holding part 420, and the suction pipe 421 is in communication with a peripheral edge suction mechanism 422 such as a vacuum pump. A peripheral edge pressure sensor 423 that measures the suction pressure is provided on the suction pipe 421. The configuration of the peripheral edge pressure sensor 423 is also arbitrary, but for example, a diaphragm-type pressure gauge is used.

[0119] 31, a recessed portion 400a is formed in the peripheral portion of the attraction plate 400, in the portion where the peripheral holding portion 420 is provided, and is recessed above the central holding portion 410. As will be described later, the peripheral portion We is pushed up and removed by the peripheral removing portion 440, and the recessed portion 400a ensures a space into which the peripheral portion We is pushed up.

[0120] With this configuration, the central holding portion 410 and the peripheral holding portion 420 can individually suck and hold the central portion Wc and the peripheral portion We. Furthermore, the central pressure sensor 413 and the peripheral pressure sensor 423 can individually measure the pressure sucking the central portion Wc and the pressure sucking the peripheral portion We.

[0121] A rotation mechanism 430 that rotates the attraction plate 400 around a vertical axis is provided on the upper surface of the attraction plate 400. The rotation mechanism 430 is supported by a support member 431. In addition, the support member 431 (rotation mechanism 430) is supported by an arm member 72.

[0122] A plurality of peripheral edge removing portions 440 are provided on the sides of the attraction plate 400 along the circumferential direction of the attraction plate 400. Each peripheral edge removing portion 440 has a wedge roller 441 and a support roller 442.

[0123] The wedge roller 441 has a wedge shape with a pointed tip in a side view. The wedge roller 441 is inserted into the interface between the processing wafer W and the support wafer S from the outer edges of the processing wafer W and the support wafer S. The inserted wedge roller 441 then pushes up the peripheral edge We, separating it from the processing wafer W and removing it.

[0124] The support roller 442 passes through the center of the wedge roller 441 and supports the wedge roller 441. The support roller 442 is configured to be movable horizontally by a movement mechanism (not shown), and the movement of the support roller 442 causes the wedge roller 441 to move as well. The support roller 442 is also configured to be rotatable about a vertical axis, and the rotation of the support roller 442 causes the wedge roller 441 to rotate as well. In this embodiment, a so-called free roller is used as the support roller 442, which rotates in response to the rotation of the chuck 100, as will be described later. However, the support roller 442 may also be actively rotated by a rotation mechanism (not shown).

[0125] A rotating shaft 443 is provided on the upper surface of the support roller 442, and the rotating shaft 443 is supported by a moving mechanism 444. The moving mechanism 444 is provided on the outer periphery of the upper surface of the support member 431. The moving mechanism 444 is, for example, an air cylinder, and can move the wedge roller 441 and the support roller 442 in the horizontal direction via the rotating shaft 443.

[0126] In wafer processing according to the third embodiment, first, the overlapped wafer T shown in Fig. 29(a) is transferred to the modifying apparatus 60. In the modifying apparatus 60, a peripheral modified layer M11 and divided modified layers M21 are sequentially formed on the processing wafer W as shown in Fig. 29(b) (steps C1 and C2 in Fig. 28). Note that the method for forming the peripheral modified layer M11 in step C1 is the same as that in step A1, and the method for forming the divided modified layers M21 in step C2 is the same as that in step A2.

[0127] Next, the transfer arm 71 of the wafer transfer device 70 enters the inside of the modifying device 60, and the peripheral edge We is removed as shown in FIG. 29(c) (Step C3 in FIG. 28).

[0128] In step C3, first, the back surface Wb of the processing wafer W is suction-held by the suction plate 400 of the transfer arm 71. Then, as shown in FIG. 32(a), the wedge roller 441 is moved toward the overlapping wafer T, and the wedge roller 441 is brought into contact with the interface between the processing wafer W and the support wafer S. At this time, by rotating the suction plate 400, the wedge roller 441 also rotates in the opposite direction in plan view. Next, as shown in FIG. 32(b), while rotating the suction plate 400, the wedge roller 441 is further moved and inserted into the interface between the processing wafer W and the support wafer S. This pushes up the peripheral edge We, separating it from the processing wafer W and holding it by suction on the peripheral edge holder 420.

[0129] Thereafter, the transport arm 71 withdraws from the reforming device 60 while the peripheral edge holding portion 420 suction-holds the peripheral edge We and the multiple wedge rollers 441 hold the peripheral edge We. Then, the peripheral edge We is collected in a collection portion (not shown) provided outside the reforming device 60.

[0130] When removing the peripheral portion We, the central pressure sensor 413 and the peripheral pressure sensor 423 measure the pressure for sucking the central portion Wc and the pressure for sucking the peripheral portion We, respectively. If the peripheral portion We is properly removed, the pressure for sucking the central portion Wc is zero, and the pressure for sucking the peripheral portion We is a predetermined pressure. On the other hand, if the peripheral portion We is not properly removed, for example, the pressure for sucking the peripheral portion We is zero. By measuring the suction pressure with the central pressure sensor 413 and the peripheral pressure sensor 423 in this way, the presence or absence of the peripheral portion We on the processing wafer W can be detected, and it can be confirmed whether the peripheral portion We has been removed from the processing wafer W.

[0131] Next, in the reforming device 60, an inner surface modified layer M31 is formed as shown in Figure 29(d) (Step C4 in Figure 28). The method for forming the inner surface modified layer M31 in Step C4 is the same as in Step A3.

[0132] Next, the overlapped wafer T is transferred to the processing device 80 by the wafer transfer device 70. In the processing device 80, first, when the overlapped wafer T is transferred from the transfer arm 71 to the chuck 81, the back surface Wb side of the processing wafer W (hereinafter referred to as the back surface wafer Wb3) is separated using the internal surface modification layer M31 as a base point, as shown in FIG. 29(e) (step C5 in FIG. 28). The method for separating the processing wafer W in step C5 is the same as that in step A5. Furthermore, the separation of the processing wafer W is not limited to the method using the transfer arm 71, and may be performed using, for example, an apparatus similar to the edge removal apparatus 61 shown in FIG. 20.

[0133] 29(f), the back surface Wb of the processing wafer W is ground (step C6 in FIG. 28), followed by cleaning of the back surface Wb in the cleaning apparatus 41 (step C7 in FIG. 28) and wet etching of the back surface Wb in the etching apparatus 40 (step C8 in FIG. 28). In this way, a series of wafer processing steps in the wafer processing system 1 is completed.

[0134] In this embodiment, a peripheral modified layer M11 and an internal surface modified layer M31 are formed in this order inside the processing wafer W, and the same effects as those of the first embodiment can be obtained. Moreover, the formation of the peripheral modified layer M11 in step C1, the removal of the peripheral portion We in step C3, and the formation of the internal surface modified layer M31 in step C4 are performed in a single modifying apparatus 60, so that the throughput of wafer processing can be maintained. Note that in this embodiment, the removal of the peripheral portion We in step C3 is performed inside the modifying apparatus 60, but of course it may be performed in a separate apparatus.

[0135] Next, another embodiment of the reforming device 60 will be described. In the above embodiment, the reforming device 60 is provided with one laser head 110. However, as shown in FIG. 33, a plurality of laser heads, for example, two laser heads 110 and 500, may be provided. For convenience of explanation, in this embodiment, the laser head 110 is referred to as the first laser head 110, and the laser head 500 is referred to as the second laser head 500. Note that the number of laser heads is not limited to this embodiment. In addition, in FIG. 33, the macro camera 140 and the micro camera 150 are omitted from illustration to avoid complication.

[0136] The second laser head 500 is provided on the positive Y-axis side of the first laser head 110. The configuration of the second laser head 500 is similar to the configuration of the first laser head 110. That is, the second laser head 500 has a lens 501 and an LCOS (not shown).

[0137] The support structure of the second laser head 500 is similar to that of the first laser head 110. That is, the second laser head 500 is supported by a support member 510, a rail 511, an elevating mechanism 520, and a moving mechanism 521. The second laser head 500 is configured to be able to move up and down freely and move in the Y-axis direction.

[0138] In this case, for example, when forming the peripheral modified layer M1 in the first embodiment, the first laser head 110 and the second laser head 500 are arranged concentrically around the outer periphery of the processing wafer W, as shown in FIG. 34 . Then, while rotating the processing wafer W, the first laser head 110 irradiates the processing wafer W with laser light L12, and the second laser head 500 irradiates the processing wafer W with laser light L13. The peripheral modified layer M12 is formed by the laser light L12, and the peripheral modified layer M13 is formed by the laser light L13. The peripheral modified layers M12 and M13 are each formed on half the circumference of the processing wafer W, and together these peripheral modified layers M12 and M13 form the annular peripheral modified layer M1. That is, in this embodiment, the processing wafer W only needs to be rotated 180 degrees to form the peripheral modified layer M1. This shortens the time required to form the peripheral modified layer M1, thereby further improving wafer processing throughput.

[0139] In the above example, the laser beam L12 from the first laser head 110 and the laser beam L13 from the second laser head 500 are irradiated to the same depth inside the processing wafer W, and the peripheral modified layer M12 and the peripheral modified layer M13 are formed to the same depth. However, the laser beam L12 and the laser beam L13 may be irradiated to different depths, and the peripheral modified layer M12 and the peripheral modified layer M13 may be formed to different depths.

[0140] Furthermore, when forming the internal surface modified layer M3, the first laser head 110 and the second laser head 500 are arranged concentrically around the outer periphery of the processing wafer W, as shown in FIG. 35. Then, the processing wafer W is rotated, and the first laser head 110 and the second laser head 500 are each moved in the Y-axis direction from the outer periphery toward the center of the processing wafer W. That is, the first laser head 110 is moved in the positive direction of the Y-axis, and the second laser head 500 is moved in the negative direction of the Y-axis. During this rotation of the processing wafer W and the movement of the laser heads 110 and 500, the first laser head 110 irradiates the interior of the processing wafer W with laser light L32, and the second laser head 500 irradiates the interior of the processing wafer W with laser light L33. As a result, the internal surface modified layer M32 is formed by the laser light L32, and the internal surface modified layer M33 is formed by the laser light L33. The internal surface modification layers M32 and M33 are each formed in a spiral shape, and the internal surface modification layer M3 is formed on the entire surface of the processing wafer W. By simultaneously forming the internal surface modification layers M32 and M33 in this manner, the time required to form the internal surface modification layer M3 can be shortened, and as a result, the throughput of wafer processing can be further improved.

[0141] In the above embodiment, the divided modified layer M2 is formed using the laser head 110 used in the reforming device 60 to form the other peripheral modified layer M1 and internal surface modified layer M3, but a separate laser head (not shown) may also be used. Furthermore, in the reforming device 60, the peripheral modified layer M1, the divided modified layer M2, and the internal surface modified layer M3 may each be formed using a separate laser head (not shown).

[0142] For example, in the above embodiment, the unbonded region Ab is formed at the interface between the processing wafer W and the support wafer S before bonding, but the unbonded region Ab may also be formed after bonding. For example, after bonding, the outer periphery of the oxide film F can be irradiated with laser light to reduce the bonding strength and form the unbonded region Ab.

[0143] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive, and the above-described embodiments may be omitted, substituted, or modified in various ways without departing from the scope and spirit of the appended claims. [Explanation of symbols]

[0144] 1. Wafer Processing System 60 Reformer 100 Chuck 110 Laser Head S Support wafer T Polymerized Wafer W processed wafer

Claims

1. A substrate processing apparatus for processing a substrate, a substrate holder that holds the second substrate in a laminated substrate formed by bonding a first substrate and a second substrate; a modification device having a lens that irradiates the inside of the first substrate of the laminated substrate held by the substrate holder with laser light to form a peripheral modified layer along the boundary between the peripheral portion and the central portion to be removed; a program storage unit for storing a program; a control device having a computer that reads the program from the program storage unit and runs the program, The laminated substrate has a bonded region where a surface of the first substrate and a surface of the second substrate are bonded, and an unbonded region that is a region radially outward of the bonded region, The program a program that runs on the computer of the control device and controls the substrate processing apparatus to cause the substrate processing apparatus to perform a substrate processing method, The substrate processing method includes: irradiating the laser light radially inward of the outer end of the bonding region so that the distance between the peripheral modified layer and the outer end of the bonding region is within 500 μm.

2. 2. The substrate processing apparatus according to claim 1, wherein the substrate processing method includes irradiating the peripheral laser light radially inward of the outer end of the bonding region so that a distance between the peripheral modified layer and the outer end of the bonding region is within 50 μm.

3. The substrate processing apparatus according to claim 1 , further comprising an imaging unit configured to be able to acquire an image by imaging a boundary between the bonded region and the unbonded region of the laminated substrate.

4. The substrate processing apparatus according to claim 3 , wherein the control device executes control including correcting, based on the image, a deviation between a position where the peripheral modified layer is formed and the outer edge of the bonding region.

5. the control device holds the second substrate on the laminated substrate by the substrate holder configured to be rotatable around an axis perpendicular to the laminated substrate; calculating an amount of eccentricity between a rotation center of the substrate holder and a center of the bonding area from the image; and correcting the misalignment by adjusting a relative position between a position where the peripheral modified layer is formed and the outer end of the bonding region based on the amount of eccentricity.

6. the substrate holder has a moving mechanism, The substrate processing apparatus according to claim 5 , wherein the control device executes control including adjusting, by the moving mechanism, the relative position between the position where the peripheral modified layer is formed and the outer end of the bonding region.

7. The imaging unit a micro camera configured to be able to acquire the image by capturing an image of a boundary between the bonded region and the unbonded region in the laminated substrate; and a macro camera configured to capture an image of an outer edge of the laminated substrate, the control device captures an image of the outer edge of the laminated substrate with the macro camera to obtain a second image; calculating a second eccentricity amount between the center of the substrate holder and the center of the laminated substrate from the second image; and determining a position at which the micro camera can capture an image of the boundary between the bonded region and the unbonded region in the laminated substrate based on the second amount of eccentricity.

8. A program that runs on a computer of a control device that controls a substrate processing apparatus so as to cause the substrate processing apparatus to perform a substrate processing method, the program comprising: The substrate processing apparatus includes: a substrate holder that holds the second substrate in a laminated substrate formed by bonding a first substrate and a second substrate; a modification device having a lens that irradiates the inside of the first substrate of the laminated substrate held by the substrate holder with laser light to form a peripheral modified layer along the boundary between the peripheral portion and the central portion to be removed; the control device having a program storage unit for storing the program, The laminated substrate has a bonded region where a surface of the first substrate and a surface of the second substrate are bonded, and an unbonded region that is a region radially outward of the bonded region, The substrate processing method includes a program that controls the modification device to irradiate the laser light radially inward of the outer end of the bonding area so that the distance between the peripheral modification layer and the outer end of the bonding area is within 500 μm.

9. The substrate processing method according to claim 8, wherein, in forming the peripheral modification layer, the peripheral laser light is irradiated radially inward of the outer end of the bonding region so that the distance between the peripheral modification layer and the outer end of the bonding region is within 50 μm.

10. The program according to claim 8 , wherein the substrate processing method comprises acquiring an image by using an imaging unit to capture an image of a boundary between the bonded region and the unbonded region in the laminated substrate.

11. The program according to claim 10 , wherein the substrate processing method comprises correcting, from the image, a deviation between a position where the peripheral modified layer is formed and the outer edge of the bonding region.

12. The substrate processing method includes holding the second substrate on the overlapped substrate by a substrate holding unit configured to be rotatable around an axis perpendicular to the overlapped substrate; calculating an amount of eccentricity between a rotation center of the substrate holder and a center of the bonding area from the image; and correcting the deviation by adjusting a relative position between a position where the peripheral modified layer is formed and the outer end of the bonding region based on the amount of eccentricity.

13. A computer-readable storage medium storing a program that runs on a computer of a control device that controls a substrate processing apparatus so as to cause the substrate processing apparatus to execute a substrate processing method, the computer-readable storage medium comprising: The substrate processing apparatus includes: a substrate holder that holds the second substrate in a laminated substrate formed by bonding a first substrate and a second substrate; a modification device having a lens that irradiates the inside of the first substrate of the laminated substrate held by the substrate holder with laser light to form a peripheral modified layer along the boundary between the peripheral portion and the central portion to be removed; the control device having a program storage unit for storing the program, The laminated substrate has a bonded region where a surface of the first substrate and a surface of the second substrate are bonded, and an unbonded region that is a region radially outward of the bonded region, The substrate processing method includes controlling the modification device to irradiate the laser light radially inward from the outer end of the bonding area so that the distance between the peripheral modification layer and the outer end of the bonding area is within 500 μm.

14. The storage medium of claim 8, wherein the substrate processing method, in forming the peripheral modification layer, irradiates the peripheral laser light radially inward from the outer end of the bonding region so that the distance between the peripheral modification layer and the outer end of the bonding region is within 50 μm.

15. The storage medium according to claim 8 , wherein the substrate processing method comprises acquiring an image by using an imaging unit to capture an image of a boundary between the bonded region and the unbonded region in the laminated substrate.

16. The storage medium according to claim 10 , wherein the substrate processing method comprises correcting, from the image, a deviation between a position where the peripheral modified layer is formed and the outer edge of the bonding region.

17. The substrate processing method includes holding the second substrate on the overlapped substrate by a substrate holding unit configured to be rotatable around an axis perpendicular to the overlapped substrate; calculating an amount of eccentricity between a rotation center of the substrate holder and a center of the bonding area from the image; The storage medium according to claim 11 , further comprising: correcting the misalignment by adjusting a relative position between a position where the peripheral modified layer is formed and the outer end of the bonding region based on the amount of eccentricity.

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