Substrate processing device and substrate processing method

Abstract

To remove a peripheral portion of one substrate appropriately in a combined substrate having substrates bonded to each other.SOLUTION: There is provided a substrate processing device configured to process a combined substrate having a first substrate and a second substrate bonded to each other. The substrate processing device includes: a chuck which holds, in a state where the first substrate is disposed at an upper side and the second substrate is disposed at a lower side, the combined substrate that includes a modification layer formed within the first substrate along a boundary between a peripheral portion of the first substrate to be removed and a central portion thereof by irradiation with laser light from a processing surface side of the first substrate, and another modification layer formed to break the peripheral portion into small pieces when the peripheral portion is removed, radially outward from the boundary within the first substrate; and a driver moving a grinding wheel provided above the chuck in a vertical direction. The first substrate is brought into contact with the grinding wheel to remove the peripheral portion with the modification layer and the other modification layer as a base point.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] (CROSS REFERENCE TO RELATED APPLICATIONS) This application claims priority based on Japanese Patent Application No. 2018-47159, filed in Japan on March 14, 2018, and Japanese Patent Application No. 2018-87711, filed in Japan on April 27, 2018, the contents of which are incorporated herein by reference.

[0002] The present invention relates to a substrate processing apparatus and a substrate processing method. [Background technology]

[0003] In recent years, in the manufacturing process of semiconductor devices, a semiconductor wafer (hereinafter referred to as a wafer) having a plurality of electronic circuits and other devices formed on its surface is thinned by grinding the back surface of the wafer. If the thinned wafer is transported as is or subjected to subsequent processing, there is a risk that the wafer may warp or crack. Therefore, in order to reinforce the wafer, for example, the wafer is attached to a support substrate.

[0004] By the way, the peripheral edge of the wafer is usually chamfered, but as described above, when the wafer is ground, the peripheral edge of the wafer becomes sharp (so-called knife edge shape). This may cause chipping at the peripheral edge of the wafer, which may damage the wafer. Therefore, so-called edge trimming is performed to remove the peripheral edge of the wafer before the grinding process.

[0005] For example, Patent Document 1 discloses a vertical-axis type end face grinding device as a device for performing edge trimming. When using this end face grinding device to grind the peripheral portion of a wafer, first, a wafer with a support substrate attached thereto is fixed to a table, and the table is rotated around an axis parallel to the vertical axis. Then, the spindle is rotated to rotate a wheel, which is a grinding tool, and the spindle is moved vertically to bring the grinding surface of the wheel into contact with the wafer, thereby grinding the peripheral portion of the wafer. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 9-216152 Summary of the Invention [Problem to be solved by the invention]

[0007] However, in the end face grinding device described in Patent Document 1, the vertical movement of the spindle may not be constant due to various factors such as tolerances. In such cases, the vertical movement of the wheel may not be properly controlled, and the surface of the support substrate may be ground away. Therefore, there is room for improvement in the conventional edge trim.

[0008] The present invention has been made in view of the above circumstances, and has an object to appropriately remove the peripheral edge portion of one of substrates in a laminated substrate in which substrates are bonded together. [Means for solving the problem]

[0009] One aspect of the present invention that solves the above problem is a substrate processing device that processes a laminated substrate in which a first substrate and a second substrate are bonded, and includes a laser light irradiated from the processing surface side of the first substrate, and a modified layer formed inside the first substrate along the boundary between the peripheral portion and the central portion of the first substrate to be removed, and another modified layer formed inside the first substrate radially outward from the boundary for breaking the peripheral portion into small pieces when removing the peripheral portion. The substrate processing device has a chuck that holds the laminated substrate with the first substrate on the upper side and the second substrate on the lower side, and a drive unit that moves a grinding wheel provided above the chuck in a vertical direction, and the first substrate and the grinding wheel are brought into contact with each other to remove the peripheral portion based on the modified layer and the other modified layer.

[0010] Another aspect of the present invention is a substrate processing method for processing an overlapped substrate formed by bonding a first substrate and a second substrate, comprising: irradiating a laser beam from the processing surface side of the first substrate; holding the overlapped substrate including a modified layer formed inside the first substrate along the boundary between the peripheral portion and central portion to be removed in the first substrate, and another modified layer formed inside the first substrate radially outward from the boundary for breaking the peripheral portion into small pieces when removing the peripheral portion, on a chuck with the first substrate arranged on the upper side and the second substrate arranged on the lower side; and abutting the first substrate against a grinding wheel provided above the chuck to remove the peripheral portion based on the modified layer and the other modified layer. Effect of the Invention

[0011] According to one aspect of the present invention, in a laminated substrate in which substrates are bonded together, a peripheral portion of one substrate can be appropriately removed. [Brief description of the drawings]

[0012] [Figure 1] 1 is a plan view diagrammatically illustrating an outline of the configuration of a substrate processing system according to a first embodiment. [Diagram 2] FIG. 2 is a side view showing an outline of a configuration of an overlapping wafer. [Diagram 3] FIG. 2 is a side view showing an outline of the configuration of a modified layer forming device. [Figure 4] 4 is a vertical cross-sectional view showing a state in which a modified layer is formed on a processed wafer. FIG. [Diagram 5] 11 is a plan view showing a state in which a modified layer is formed on a processed wafer. FIG. [Figure 6] 2 is a side view showing an outline of the configuration of a grinding unit of the processing device. FIG. [Figure 7] 1A to 1C are explanatory views showing the state of a processed wafer in main steps of the wafer processing according to the first embodiment. [Figure 8] 5A to 5C are explanatory views showing the state of a processed wafer in main steps of a wafer processing according to a modified example of the first embodiment. [Figure 9]FIG. 11 is a plan view illustrating a schematic configuration of a substrate processing system according to a second embodiment. [Figure 10] FIG. 2 is a side view showing an outline of the configuration of the edge removing device. [Figure 11] 10A to 10C are explanatory views showing the state of a processed wafer in main steps of the wafer processing according to the second embodiment. [Figure 12] 10A to 10C are explanatory views showing the state of a processed wafer in main steps of a wafer processing according to another embodiment. [Figure 13] 10A to 10C are explanatory views showing the state of a processed wafer in main steps of a wafer processing according to another embodiment. [Figure 14] 11 is a vertical cross-sectional view showing a state in which a modified layer is formed on a processed wafer in another embodiment. FIG. [Figure 15] 10A to 10C are explanatory views showing a state in which a modified layer is formed on a processing target wafer in another embodiment. [Figure 16] 13 is a plan view showing a state in which a modified layer is formed on a processed wafer in another embodiment. FIG. [Figure 17] 13 is a plan view showing a state in which a modified layer is formed on a processed wafer in another embodiment. FIG. [Figure 18] 13 is a plan view showing a state in which a modified layer is formed on a processed wafer in another embodiment. FIG. [Figure 19] 11 is a vertical cross-sectional view showing a state in which a modified layer is formed on a processed wafer in another embodiment. FIG. [Figure 20] FIG. 2 is a side view showing the outline of the configuration of the interface treatment device; [Figure 21] 13 is a plan view showing a state in which modified grooves are formed in a processed wafer in another embodiment. FIG. [Figure 22] 13 is a plan view showing a state in which a modified surface is formed on a processed wafer in another embodiment. FIG. [Figure 23] 10A to 10C are explanatory views showing the state of a processed wafer in main steps of a wafer processing according to another embodiment. [Figure 24] FIG. 2 is a side view showing the outline of the configuration of the interface treatment device; [Diagram 25]FIG. 2 is a side view showing an outline of the configuration of the processing apparatus. [Figure 26] 11 is a vertical cross-sectional view showing a state in which a modified surface is formed inside a processed wafer in another embodiment. FIG. [Figure 27] 27 is an explanatory diagram of a vertical cross section showing how the modified surface shown in FIG. 26 is formed. [Figure 28] 11 is a vertical cross-sectional view showing a state in which a modified surface is formed on a device layer of a processed wafer in another embodiment. FIG. [Figure 29] 29 is an explanatory diagram of a vertical cross section showing how the modified surface shown in FIG. 28 is formed. [Diagram 30] 10A to 10C are explanatory views showing the state of a processed wafer in main steps of a wafer processing according to another embodiment. [Diagram 31] 1 is a plan view showing a state in which a wafer to be processed is decentered in an overlapping wafer; [Diagram 32] 13 is an explanatory diagram illustrating a case where the modified layer is located radially inward from the inner circumference of the modified surface. FIG. [Diagram 33] 13 is an explanatory diagram illustrating a case where the modified layer is located radially outward from the inner periphery of the modified surface. FIG. [Diagram 34] FIG. 2 is a side view showing an outline of the configuration of the processing apparatus. [Diagram 35] FIG. 11 is a plan view illustrating a schematic configuration of a substrate processing system according to a third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In this specification and the drawings, elements having substantially the same functional configurations are denoted by the same reference numerals, and duplicated description will be omitted.

[0014] First, a first embodiment of the present invention will be described. Fig. 1 is a plan view showing a schematic outline of the configuration of a substrate processing system 1 according to the first embodiment. In the following, in order to clarify the positional relationship, the mutually orthogonal X-axis, Y-axis, and Z-axis directions are defined, and the positive Z-axis direction is defined as the vertically upward direction.

[0015] 2, the substrate processing system 1 bonds a process target wafer W as a first substrate and a support wafer S as a second substrate to form an overlapped wafer T as an overlapped substrate, and then thins the process target wafer W. Hereinafter, the surface of the process target wafer W to be processed (the surface opposite to the surface bonded to the support wafer S) is referred to as the "processing surface Wg," and the surface opposite to the processing surface Wg is referred to as the "non-processing surface Wn." Additionally, the surface of the support wafer S to be bonded to the process target wafer W is referred to as the "bonding surface Sj," and the surface opposite to the bonding surface Sj is referred to as the "non-bonding surface Sn."

[0016] The processing target wafer W is a semiconductor wafer such as a silicon wafer, and a plurality of devices are formed on the non-processing surface Wn. The peripheral portion of the processing target wafer W is chamfered, and the cross section of the peripheral portion has a smaller thickness toward the tip.

[0017] The support wafer S is a wafer that supports the processed wafer W. The support wafer S also functions as a protective material that protects devices on the non-processing surface Wn of the processed wafer W. When multiple devices are formed on the bonding surface Sj of the support wafer S, a device layer (not shown) is formed on the bonding surface Sj in the same manner as the processed wafer W.

[0018] As shown in FIG. 1, the substrate processing system 1 has a configuration in which a loading / unloading station 2 through which cassettes Cw, Cs, and Ct capable of accommodating multiple wafers W to be processed, multiple support wafers S, and multiple overlapping wafers T, respectively, are loaded and unloaded from, for example, the outside, and a processing station 3 equipped with various processing devices that perform predetermined processing on the wafers W to be processed, the support wafer S, and the overlapping wafers T are integrally connected.

[0019] The loading / unloading station 2 is provided with a cassette mounting table 10. In the illustrated example, a plurality of cassettes, for example, four cassettes Cw, Cs, and Ct, can be freely mounted on the cassette mounting table 10 in a line in the X-axis direction. Note that the number of cassettes Cw, Cs, and Ct mounted on the cassette mounting table 10 is not limited to that in this embodiment, and can be determined arbitrarily.

[0020] The loading / unloading station 2 is provided with a wafer transport area 20 adjacent to the cassette placement table 10. The wafer transport area 20 is provided with a wafer transport device 22 that is movable on a transport path 21 extending in the X-axis direction. The wafer transport device 22 has, for example, two transport arms 23, 23 that hold and transport the overlapped wafer T. Each transport arm 23 is configured to be movable horizontally, vertically, around a horizontal axis, and around a vertical axis. The configuration of the transport arm 23 is not limited to this embodiment, and any configuration may be used.

[0021] In the processing station 3, a bonding device 30 for bonding the processing target wafer W and the support wafer S, a modified layer forming device 31 for forming a modified layer inside the processing target wafer W, and a processing device 32 for grinding and processing the processing surface Wg of the processing target wafer W are arranged side by side from the negative direction to the positive direction of the X axis on the Y-axis positive side of the wafer transfer area 20. Note that the number and arrangement of these bonding devices 30, modified layer forming devices 31, and processing devices 32 are not limited to this embodiment and can be determined arbitrarily. Also, in this embodiment, the processing device 32 functions as the peripheral edge removing device of the present invention.

[0022] The substrate processing system 1 described above is provided with a control device 40. The control device 40 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 target wafer W, the support wafer S, and the overlapped wafer T in the substrate processing system 1. The program storage unit also stores a program for controlling the operation of the drive systems of the above-mentioned various processing devices and the transfer device, and for realizing wafer processing, which will be described later, in the substrate processing system 1. The program may be recorded in a computer-readable storage medium H, such as a computer-readable hard disk (HD), a flexible disk (FD), a compact disk (CD), a magnet optical disk (MO), or a memory card, and may be installed in the control device 40 from the storage medium H.

[0023] Next, the bonding device 30, the modified layer forming device 31, and the processing device 32 will be described.

[0024] The bonding device 30 bonds the non-processed surface Wn of the processing wafer W and the bonding surface Sj of the support wafer S by van der Waals forces and hydrogen bonds (intermolecular forces). During this bonding, it is preferable that the non-processed surface Wn and the bonding surface Sj are modified and hydrophilized. Specifically, when modifying the non-processed surface Wn and the bonding surface Sj, for example, oxygen gas or nitrogen gas, which is a processing gas, is excited to be plasmatized and ionized under a reduced pressure atmosphere. The oxygen ions or nitrogen ions are irradiated onto the non-processed surface Wn and the bonding surface Sj, and the non-processed surface Wn and the bonding surface Sj are plasma-treated and activated. In addition, pure water is supplied to the modified non-processed surface Wn and the bonding surface Sj to make the non-processed surface Wn and the bonding surface Sj hydrophilic. The configuration of the bonding device 30 is arbitrary, and a known bonding device can be used.

[0025] The modified layer forming apparatus 31 irradiates the inside of the processing target wafer W with laser light to form a modified layer. The modified layer forming apparatus 31 has a chuck 100 as a holding unit that holds the overlapped wafer T with the processing target wafer W placed on the upper side and the support wafer S placed on the lower side as shown in FIG. 3. The chuck 100 is configured to be movable in the X-axis direction and the Y-axis direction by a moving mechanism 101. The moving mechanism 101 is configured as a general precision XY stage. The chuck 100 is also configured to be rotatable around a vertical axis by a rotating mechanism 102.

[0026] Above the chuck 100, a laser head 103 is provided as a modification unit for irradiating the inside of the wafer W with laser light. The laser head 103 irradiates a high-frequency pulsed laser light oscillated from a laser light oscillator (not shown) with a wavelength that is transparent to the wafer W, by concentrating the laser light at a predetermined position inside the wafer W. As a result, as shown in FIG. 4, the part inside the wafer W where the laser light L is concentrated is modified to form a modified layer M. The modified layer M extends in the plate thickness direction and has a vertical aspect ratio. As shown in FIG. 3, the laser head 103 may be configured to be movable in the X-axis direction and the Y-axis direction by a moving mechanism 104. The moving mechanism 104 is configured with a general precision XY stage. The laser head 103 may also be configured to be movable in the Z-axis direction by a lifting mechanism 105.

[0027] In the modified layer forming apparatus 31, first, the overlapped wafer T is held by the chuck 100, and then the chuck 100 is moved horizontally by the moving mechanism 101 to center the overlapped wafer T, and the laser head 103 is adjusted by the moving mechanism 104 so that it is located directly above a predetermined position of the overlapped wafer T (processed wafer W). Thereafter, while rotating the chuck 100 by the rotating mechanism 102, the laser head 103 irradiates the inside of the processed wafer W with laser light L, thereby forming an annular modified layer M on the processed wafer W as shown in FIG. 5. In order to perform the above-mentioned position adjustment, the modified layer forming apparatus 31 may be provided with a camera (not shown) that captures an image of the position of the overlapped wafer T.

[0028] The position where the modified layer M is formed on the processing target wafer W will be described in detail. In the substrate processing system 1, the processing surface Wg of the processing target wafer W bonded to the support wafer S is ground, but in order to prevent a knife edge from being formed on the peripheral portion of the processing target wafer W after grinding, the peripheral portion is removed before grinding. The modified layer M serves as a base point when removing the peripheral portion, and is formed in a ring shape along the boundary between the peripheral portion We and the central portion Wc to be removed in the processing target wafer W, as shown in FIG. 5. The peripheral portion We is, for example, in the range of 0.5 mm to 2.0 mm in the radial direction from the end of the processing target wafer W, and includes the chamfered portion.

[0029] As shown in Fig. 4, the bottom end of the modified layer M is located above the target surface (dotted line in Fig. 4) of the processed wafer W after grinding. That is, the distance H1 between the bottom end of the modified layer M and the non-processed surface Wn of the processed wafer W is greater than the target thickness H2 of the processed wafer W after grinding. The distance H1 is arbitrary, but is, for example, 5 µm to 10 µm greater than the target thickness H2. In such a case, the modified layer M does not remain on the processed wafer W after grinding.

[0030] In the modified layer forming apparatus 31 of the present embodiment, the chuck 100 is moved horizontally, but the laser head 103 may be moved horizontally, or both the chuck 100 and the laser head 103 may be moved horizontally. Also, the chuck 100 is rotated, but the laser head 103 may be rotated.

[0031] The processing device 32 grinds and processes the processing surface Wg of the processing target wafer W. Specifically, the processing device 32 includes, for example, a grinding unit that grinds the processing surface Wg, a cleaning unit that cleans the processing surface Wg of the processing target wafer W and the non-bonding surface Sn of the support wafer S, and the like.

[0032] 6, the grinding unit 110 has a chuck 111 that holds the overlapped wafer T with the processing target wafer W on the upper side and the support wafer S on the lower side. The chuck 111 is configured to be rotatable about a vertical axis by a rotation mechanism (not shown).

[0033] An annular grinding wheel 112 is provided above the chuck 111. A drive unit 114 is provided to the grinding wheel 112 via a spindle 113. The drive unit 114 has, for example, a built-in motor (not shown) and rotates the grinding wheel 112 while moving it vertically and horizontally.

[0034] In the grinding unit 110, the processing surface Wg of the processing wafer W is ground by rotating the chuck 111 and the grinding wheel 112 while a portion of the arc of the processing wafer W held by the chuck 111 is in contact with the grinding wheel 112.

[0035] Next, a wafer processing performed using the substrate processing system 1 configured as above will be described.

[0036] First, a cassette Cw containing a plurality of wafers W to be processed and a cassette Cs containing a plurality of support wafers S are placed on the cassette placement table 10 of the carry-in / out station 2 .

[0037] Next, the wafer W to be processed is taken out of the cassette Cw by the wafer transport device 22 and transported to the bonding device 30. The support wafer S is also taken out of the cassette Cs by the wafer transport device 22 and transported to the bonding device 30. In the bonding device 30, the wafer W to be processed is arranged on the upper side and the support wafer S on the lower side, and the two wafers are bonded together by van der Waals forces and intermolecular forces to form a laminated wafer T. At this time, if the non-processed surface Wn of the wafer W to be processed and the bonding surface Sj of the support wafer S are activated by, for example, plasmatized oxygen ions or nitrogen ions, the van der Waals forces and intermolecular forces are appropriately generated.

[0038] Next, the overlapped wafer T is transported to the modified layer forming device 31 by the wafer transport device 22. The overlapped wafer T transported to the modified layer forming device 31 is handed over to and held by the chuck 100. Thereafter, the chuck 100 is moved horizontally by the moving mechanism 101 to center the overlapped wafer T, and the position of the laser head 103 is adjusted so that it is located directly above a predetermined position of the overlapped wafer T (processed wafer W). This predetermined position is the boundary between the peripheral portion We and the central portion Wc of the processed wafer W. Thereafter, while rotating the chuck 100 by the rotating mechanism 102, the laser head 103 irradiates the inside of the processed wafer W with laser light L to form an annular modified layer M inside the processed wafer W as shown in FIG. 7(a). The position where the modified layer M is formed is as described above with reference to FIGS. 4 and 5.

[0039] Next, the overlapped wafer T is transported to the processing device 32 by the wafer transport device 22. The overlapped wafer T transported to the processing device 32 is handed over to and held by the chuck 111. Thereafter, while the processing target wafer W and the grinding wheel 112 are in contact with each other at a portion of their arcs, as shown in FIG. 7(b), the grinding wheel 112 is lowered while the chuck 111 and the grinding wheel 112 are rotated, thereby grinding the processing surface Wg of the processing target wafer W.

[0040] During grinding of the processing surface Wg, cracks C propagate from the modified layer M in the thickness direction inside the processing wafer W, and reach the processing surface Wg and the non-processing surface Wn. The cracks C propagate in an almost linear manner because the processing wafer W has single crystal silicon. The cracks C are also formed in a ring shape in a plan view. The cracks C may also propagate when the modified layer M is formed in the modified layer forming device 31. In other words, the timing at which the cracks C are formed may be when the processing surface Wg is ground in the processing device 32, or when the modified layer M is formed in the modified layer forming device 31.

[0041] In addition, as the grinding of the processing surface Wg proceeds, the peripheral portion We of the processing wafer W is peeled off and removed from the modified layer M and the crack C as shown in FIG. 7(c). At this time, since the crack C advances in an almost linear manner as described above, the outer surface of the processing wafer W after the crack C is removed can be made flat with few irregularities. In addition, since the lower end of the modified layer M is located above the target surface of the processing wafer W after grinding as described above, the modified layer M is removed when the processing surface Wg is ground. The modified layer M is amorphous and has a weak strength. In this respect, in this embodiment, the modified layer M does not remain on the processing wafer W after grinding, so that a strong strength can be ensured.

[0042] In this manner, in the modified layer forming apparatus 31, the processing surface Wg of the processing target wafer W is ground to the target thickness while the peripheral edge portion We is removed.

[0043] Thereafter, the laminated wafer T on which all the processes have been performed is transferred by the wafer transfer device 22 to the cassette Ct on the cassette mounting table 10. In this manner, a series of wafer processing steps in the substrate processing system 1 is completed.

[0044] Next, a modified example of the first embodiment will be described. In the above, the processing target wafer W and the support wafer S are bonded by the bonding device 30, and then the modified layer M is formed inside the processing target wafer W by the modified layer forming device 31. However, in this modified example, this order is reversed.

[0045] That is, in the substrate processing system 1, first, the target wafer W is taken out of the cassette Cw by the wafer transfer device 22 and transferred to the modified layer forming device 31. In the modified layer forming device 31, a modified layer M is formed at a predetermined position inside the target wafer W, as shown in FIG.

[0046] In parallel with the formation of the modified layer M by the modified layer forming device 31 , the support wafer S in the cassette Cs is removed by the wafer transfer device 22 and transferred to the bonding device 30 .

[0047] Next, the processing target wafer W is transferred to the bonding apparatus 30 by the wafer transfer apparatus 22. In the bonding apparatus 30, the processing target wafer W and the support wafer S are bonded to each other to form an overlapped wafer T, as shown in FIG.

[0048] Next, the overlapped wafer T is transported by the wafer transport device 22 to the processing device 32. In the processing device 32, while the processing target wafer W and the grinding wheel 112 are in contact with each other at a portion of their arcs, as shown in Fig. 8(c), the grinding wheel 112 is lowered while the chuck 111 and the grinding wheel 112 are rotated, thereby grinding the processing surface Wg of the processing target wafer W. Then, as shown in Fig. 8(d), the peripheral portion We is removed and the processing surface Wg of the processing target wafer W is ground to a target thickness.

[0049] Thereafter, the laminated wafer T on which all the processes have been performed is transferred by the wafer transfer device 22 to the cassette Ct on the cassette mounting table 10. In this manner, a series of wafer processing steps in the substrate processing system 1 is completed.

[0050] According to the above first embodiment and the modified example, the following effects can be obtained. In the following explanation, the present invention will be compared with the conventional method of removing the peripheral portion of the wafer to be processed by grinding with a wheel (grinding tool). Note that, in the past, the peripheral portion of the wafer to be processed was sometimes removed using a blade (grinding tool), but this method also has the same problems as the method using a wheel.

[0051] When the peripheral portion of the wafer to be processed in the laminated wafer is ground off with a wheel after the wafer to be processed and the supporting wafer are bonded together as in the conventional method, i.e., as described in the above-mentioned Patent Document 1, the vertical movement of the wheel may not be properly controlled due to various factors such as tolerances, and the surface of the supporting wafer may be ground off. In contrast, in this embodiment, by forming a modified layer M inside the processing target wafer W, it is possible to remove the peripheral portion We using the modified layer M and the crack C as a base point. In this case, the bonding surface Sj of the supporting wafer S is not damaged by grinding or the like.

[0052] When the peripheral portion of the wafer to be processed is ground off with a wheel as in the conventional method before bonding the wafer to be processed and the support wafer, particles are generated by the grinding, and there is a risk that the particles will adhere to devices on the wafer to be processed. In contrast, in this embodiment, the peripheral portion We is peeled off and removed using the modified layer M and cracks C formed inside the processing target wafer W as starting points, so no particles are generated. Therefore, even when processing is performed on the processing target wafer W before bonding as in the modified example shown in FIG. 8, devices on the non-processing surface Wn are not contaminated.

[0053] When using a wheel as in the past, there is a limit to the horizontal position adjustment of the wheel, resulting in a variation of about several μm. This results in variation in the width of the peripheral part ground off by the wheel (trim width), resulting in poor processing accuracy. In contrast, in this embodiment, a laser is used to form the modified layer M inside the processing target wafer W, so that high accuracy of, for example, less than 1 μm can be ensured. As a result, the accuracy of the width (trim width) of the peripheral portion We that is removed with the modified layer M as a base point is also improved.

[0054] When a wheel is used as in the conventional method, the peripheral portion is ground by lowering the wheel, so there is a limit to the rotation speed of the chuck that holds the wafer to be processed, and it takes a long time to remove the peripheral portion. In contrast, in the present embodiment, a high-frequency laser is used to form the modified layer M inside the processing target wafer W, so that the rotation speed of the chuck 100 can be increased, and processing can be completed in an extremely short time. Therefore, the throughput of the wafer processing can be improved.

[0055] When wheels are used as in the past, the wheels wear out and need to be replaced periodically. In addition, grinding using wheels requires the use of grinding water, which must be treated for wastewater. This increases running costs. In contrast, in this embodiment, the laser head 103 itself does not deteriorate over time, and the frequency of maintenance can be reduced. In addition, since it is a dry process using a laser, grinding water and wastewater treatment are not required. This makes it possible to reduce running costs.

[0056] In addition, the processed wafer W, which is a semiconductor wafer, has a notch formed therein to indicate the direction of the crystal orientation, but when removing the peripheral portion We using only a conventional blade, it was difficult to leave the shape of this notch intact. In contrast, in this embodiment, for example, in the modified layer forming apparatus 31, the modified layer M can be formed to match the shape of the notch by controlling the relative movement of the processed wafer W and the laser light, and the peripheral portion We can also be easily removed while leaving the shape of the notch intact.

[0057] In the above embodiment, a method for efficiently removing the peripheral portion We during grinding of the processing surface Wg includes rotating the grinding wheel 112 from the outside to the inside of the processing target wafer W relative to the rotating processing target wafer W, or rotating the grinding wheel 112 from the inside to the outside of the processing target wafer W relative to the rotating processing target wafer W. In this way, the rotation direction of the grinding wheel 112 can be changed depending on the type of processing target wafer W and the processing step.

[0058] Furthermore, when grinding the processing surface Wg, high-pressure water may be applied to the peripheral portion We from the inside to the outside of the processing target wafer W to efficiently remove (fly away) the peripheral portion We.

[0059] In the above modification of the first embodiment, the modified layer M is formed in the modified layer forming apparatus 31, the processing target wafer W and the support wafer S are bonded in the bonding apparatus 30, and the peripheral portion We is removed in the processing apparatus 32, but the order of wafer bonding and removal of peripheral portion We may be reversed. That is, the modified layer M is formed in the modified layer forming apparatus 31, the peripheral portion We is removed in the processing apparatus 32, and the processing target wafer W and the support wafer S are bonded in the bonding apparatus 30, and the order may be reversed.

[0060] Next, a second embodiment of the present invention will be described. Fig. 9 is a plan view showing a schematic outline of the configuration of a substrate processing system 200 according to the second embodiment. The substrate processing system 200 further includes a peripheral edge removing device 210 for removing a peripheral portion We of a processing target wafer W in the processing station 3 in the configuration of the substrate processing system 1 of the first embodiment. The peripheral edge removing device 210 is disposed, for example, between the modified layer forming device 31 and the processing device 32.

[0061] After the modified layer M is formed on the processing target wafer W by the modified layer forming device 31, the peripheral edge removing device 210 removes the peripheral edge We by applying a force outward from the modified layer M. That is, in the first embodiment, the peripheral edge We is removed while the processing device 32 is grinding the processing surface Wg of the processing target wafer W, but in the second embodiment, the peripheral edge removing device 210 removes the peripheral edge We.

[0062] 10, the edge removing device 210 has a chuck 211 that holds the overlapped wafer T with the processing target wafer W placed on the upper side and the support wafer S placed on the lower side. The chuck 211 is configured to be rotatable about a vertical axis by a rotation mechanism (not shown).

[0063] An annular grinding wheel 212 is provided above the chuck 211. A drive unit 214 is provided to the grinding wheel 212 via a spindle 213. The drive unit 214 has, for example, a built-in motor (not shown), and rotates the grinding wheel 212 while moving it vertically and horizontally. Note that, although the grinding wheel 212 is used in this embodiment, the present invention is not limited to this, and for example, a blade may be used.

[0064] In the edge removal device 210, the edge We of the processing target wafer W held by the chuck 211 is in contact with a part of the arc of the grindstone wheel 212, and the chuck 211 and the grindstone wheel 212 are rotated to apply an impact to the edge We. The edge We is removed by this impact. In this case, the formation of the modified layer M can provide precision in the removal surface of the processing target wafer W.

[0065] Next, a description will be given of wafer processing performed using the substrate processing system 200 configured as above. Note that in this embodiment, detailed descriptions of processes similar to those in the first embodiment will be omitted.

[0066] First, the target wafer W is taken out of the cassette Cw by the wafer transfer device 22 and transferred to the modified layer forming device 31. In the modified layer forming device 31, a modified layer M is formed at a predetermined position inside the target wafer W, as shown in FIG.

[0067] In parallel with the formation of the modified layer M by the modified layer forming device 31 , the support wafer S in the cassette Cs is removed by the wafer transfer device 22 and transferred to the bonding device 30 .

[0068] Next, the processing target wafer W is transferred to the bonding apparatus 30 by the wafer transfer apparatus 22. In the bonding apparatus 30, the processing target wafer W and the support wafer S are bonded to each other to form an overlapped wafer T, as shown in FIG.

[0069] Next, the overlapped wafer T is transported by the wafer transport device 22 to the edge removing device 210. In the edge removing device 210, a part of the arc of the grindstone wheel 212 is brought into contact with the outside of the modified layer M of the processing target wafer W, as shown in Fig. 11(c). In this state, when the grindstone wheel 212 is lowered while the chuck 211 and the grindstone wheel 212 are rotated, an impact is applied to the edge portion We of the processing target wafer W. Due to this impact, the edge portion We is peeled off and removed from the modified layer M and the crack C as base points, as shown in Fig. 11(d).

[0070] Next, the overlapped wafer T is transferred to the processing device 32 by the wafer transfer device 22. In the processing device 32, the processing surface Wg of the processing target wafer W is ground to a target thickness as shown in FIG.

[0071] Thereafter, the overlapped wafer T on which all the processes have been performed is transferred by the wafer transfer device 22 to the cassette Ct on the cassette mounting table 10. In this manner, a series of wafer processing steps in the substrate processing system 200 is completed.

[0072] In the second embodiment described above, the same effects as in the first embodiment can be obtained.

[0073] 11 in the second embodiment, the formation of the modified layer M, bonding of the processing target wafer W and the support wafer S, removal of the peripheral portion We, and grinding of the processing surface Wg of the processing target wafer W are performed in this order, but the order of the formation of the modified layer M and the bonding of the processing target wafer W and the support wafer S may be reversed. In other words, the bonding of the processing target wafer W and the support wafer S, the formation of the modified layer M, removal of the peripheral portion We, and grinding of the processing surface Wg of the processing target wafer W may be performed in this order.

[0074] In the above embodiment, a case has been described in which one processing target wafer W is bonded to a support wafer S, but semiconductor wafers on which devices are formed may be bonded to each other, or multiple processing target wafers W on which devices are formed may be stacked. In the following description, a case will be described in which multiple processing target wafers W on which devices are formed are stacked using the substrate processing system 1 of the first embodiment.

[0075] In the overlapped wafer T that has been subjected to the wafer processing in the first embodiment, as shown in Fig. 12(a), the peripheral portion We of the processing target wafer W is removed, and the processing surface Wg is ground to a target thickness. In the following description, this first processing target wafer W is referred to as the first processing target wafer W1.

[0076] This overlapped wafer T is transported to the bonding apparatus 30 by the wafer transport apparatus 22. A wafer W to be processed as a third substrate to be stacked next is also transported to the bonding apparatus 30 by the wafer transport apparatus 22. In the following description, this second wafer W to be processed is referred to as a second wafer W2 to be processed. Then, in the bonding apparatus 30, the processing surface Wg of the first wafer W1 to be processed and the non-processing surface Wn of the second wafer W2 to be processed are bonded together as shown in FIG. 12(a) to form the overlapped wafer T.

[0077] Next, the overlapped wafer T is transferred by the wafer transfer device 22 to the modified layer forming device 31. In the modified layer forming device 31, a modified layer M is formed at a predetermined position inside the second processed wafer W2, as shown in FIG.

[0078] Next, the overlapped wafer T is transported to the processing device 32 by the wafer transport device 22. In the processing device 32, while the second processed wafer W2 is in contact with a part of the arc of the grinding wheel 112 as shown in Fig. 12(c), the grinding wheel 112 is lowered while the chuck 111 and the grinding wheel 112 are rotated, thereby grinding the processing surface Wg of the second processed wafer W2. Then, as shown in Fig. 12(d), the peripheral portion We is removed and the processing surface Wg of the second processed wafer W2 is ground to a target thickness.

[0079] Thereafter, the laminated wafer T on which all the processes have been performed is transferred by the wafer transfer device 22 to the cassette Ct on the cassette mounting table 10. In this manner, a series of wafer processing steps in the substrate processing system 1 is completed.

[0080] Here, when removing the peripheral portion We of the second processed wafer W2 from the overlapped wafer T shown in FIG. 12(a) using a wheel as in the conventional method, it is difficult to grind the peripheral portion We because the lower part of the non-processed surface Wn of the second processed wafer W2 is hollow. In contrast, in this embodiment, by forming a modified layer M inside the second processed wafer W2, the peripheral portion We can be easily removed using the modified layer M and the crack C as base points.

[0081] In addition, when using a wheel or blade as in the past, there is a limit to the horizontal position adjustment of the wheel or blade, resulting in a variation of about several μm. This results in variation in the width of the peripheral portion (trim width) ground off by the wheel or blade, and this variation accumulates especially when the wafers to be processed are stacked. This may result in, for example, the wafers to be processed in the upper layer protruding from the wafers to be processed in the lower layer. In contrast, in the present embodiment, the modified layer M is formed inside the second processed wafer W2 using a laser, so that high precision can be ensured and the processed wafers W can be stacked appropriately.

[0082] In addition, when a plurality of processing target wafers W are stacked as in this embodiment, the peripheral portion We to be removed of the upper second processing target wafer W2 may be located inside the peripheral portion We to be removed of the lower first processing target wafer W1. That is, as shown in FIG. 13(a), the modified layer M inside the second processing target wafer W2 may be formed radially inward from the end of the first processing target wafer W1. In such a case, as shown in FIG. 13(b), the diameter of the second processing target wafer W2 to be finally stacked is smaller than the diameter of the first processing target wafer W1. In this way, it is possible to reliably prevent the second processing target wafer W2 from protruding from the first processing target wafer W1.

[0083] In the modified layer forming apparatus 31 of the above embodiment, as shown in FIG. 4, the modified layer M is formed in one location so that its lower end is positioned above the target surface of the processed wafer W after grinding, but the method of forming the modified layer M is not limited to this.

[0084] As shown in Fig. 14(a) to (d), a plurality of modified layers M may be formed in the thickness direction of the processing target wafer W. Note that Fig. 14 illustrates a device layer and an oxide film formed at the interface between the processing target wafer W and the support wafer S of the overlapped wafer T. That is, a device layer D having a plurality of devices formed thereon is formed on the non-processing surface Wn of the processing target wafer W, and an oxide film Fw (e.g., a SiO2 film) is further formed on the device layer D. In addition, an oxide film Fs is also formed on the bonding surface Sj of the support wafer S. Note that, when a plurality of devices are formed on the bonding surface Sj of the support wafer S, a device layer (not shown) is formed on the bonding surface Sj in the same manner as the processing target wafer W.

[0085] 14(a), modified layers M1 to M4 are formed in multiple stages, for example, four stages, in the thickness direction of the processing target wafer W. The bottom end of the bottom modified layer M4 is located above the target surface (dotted line in FIG. 14(a)) of the processing target wafer W after grinding. Moreover, a crack C propagating through these modified layers M1 to M4 reaches the processing surface Wg and the non-processing surface Wn of the processing target wafer W.

[0086] In the example shown in FIG. 14(b), the modified layers M1-M2 are formed in multiple stages, for example, two stages, in the thickness direction of the wafer W to be processed. The lower end of the modified layer M2 of the lower layer is located above the target surface (dotted line in FIG. 14(b)) of the wafer W to be processed after grinding. The crack C propagating through these modified layers M1-M2 reaches the non-processed surface Wn of the wafer W to be processed, but does not reach the processed surface Wg. In such a case, for example, in the processing device 32, when the grinding wheel 112 is lowered to grind the processed surface Wg, the processed surface Wg is ground including the peripheral portion We of the wafer W to be processed until the grinding surface of the grinding wheel 112 reaches the crack C. Then, when the grinding surface of the grinding wheel 112 reaches the crack C, the peripheral portion We is peeled off and removed below the crack C. In this manner, by controlling the height of the top end of the crack C extending from the modified layers M1 to M2 to a predetermined position, the size (height) of the small piece of the peripheral portion We to be removed can be controlled.

[0087] In the example shown in FIG. 14(c), the modified layers M1 to M4 are formed in a plurality of stages, for example, four stages, in the thickness direction of the processing wafer W. The lower end of the modified layer M4 of the lowest layer is located below the target surface (dotted line in FIG. 14(c)) of the processing wafer W after grinding. In addition, the cracks C propagating through these modified layers M1 to M4 reach the processing surface Wg and the non-processing surface Wn of the processing wafer W. In this case, since the modified layer M4 is formed at the boundary between the peripheral portion We and the central portion Wc of the processing wafer W after grinding, the peripheral portion We can be peeled off and removed more reliably. In addition, when the modified layer M4 is formed below the target surface in this way, the laser beam is focused to be controlled so that the cracks C extending from the modified layer M4 are unlikely to occur. In this way, it is possible to suppress the cracks C from occurring even in the support wafer S bonded to the processing wafer W. Although the position of the crack C varies in the circumferential direction, the lower end of the modified layer M4 can be controlled in this manner, and therefore the layer can be removed with high precision.

[0088] In the example shown in FIG. 14(d), modified layers M1 to M4 are formed in multiple stages, for example, four stages, in the thickness direction of the processing target wafer W. The lower end of the bottommost modified layer M4 is located inside the device layer D. Furthermore, a crack C propagating through these modified layers M1 to M4 reaches the processing surface Wg of the processing target wafer W. Even in such a case, since the modified layer M4 is formed at the boundary between the peripheral portion We and the central portion Wc of the processing target wafer W after grinding, the peripheral portion We can be peeled off and removed more reliably.

[0089] As shown in Fig. 14, the method of forming the modified layers M in the thickness direction of the processing target wafer W is arbitrary, but for example, three processing methods are listed as shown in Fig. 15. Fig. 15 is a planar development of the portion of the processing target wafer W where the modified layers M are formed (the boundary between the peripheral portion We and the central portion Wc). That is, the horizontal direction in Fig. 15 indicates the circumferential direction of the boundary between the peripheral portion We and the central portion Wc, and the vertical direction indicates the thickness direction of the processing target wafer W. Also, in Fig. 15, dotted lines indicate modified layers M1 to M4, showing the state in which multiple modified layers M1 to M4 are formed in the thickness direction of the processing target wafer W.

[0090] In the processing method shown in FIG. 15(a), in the modified layer forming device 31, while rotating the chuck 100 by the rotating mechanism 102, laser light is irradiated from the laser head 103 fixed in the vertical direction to the inside of the processing target wafer W to form an annular modified layer M4. Next, the rotation of the chuck 100 is stopped, and the irradiation of the laser light from the laser head 103 is stopped, and then the laser head 103 is raised by the lifting mechanism 105 to a predetermined position, that is, a position where the modified layer M3 is to be formed. Thereafter, while rotating the chuck 100, laser light is irradiated from the laser head 103 to form the annular modified layer M3. The modified layers M2 and M1 are formed in the same manner to form the modified layers M1 to M4 on the processing target wafer W.

[0091] In addition, when forming the modified layers M1 to M4, the irradiation of the laser light from the laser head 103 may be controlled on and off while the rotation of the chuck 100 is continued. For example, while the chuck 100 is rotating, the laser head 103 irradiates the inside of the wafer W to be processed with laser light to form the modified layer M4. Thereafter, while the rotation of the chuck 100 is continuing, the irradiation of the laser light from the laser head 103 is temporarily stopped. Next, the laser head 103 is raised, and the inside of the wafer W to be processed is irradiated with laser light from the laser head 103 again to form the modified layer M3. At this time, by storing the irradiation start position and irradiation end position of the laser light when forming the modified layer M4, it is possible to match the irradiation start position and irradiation end position of the laser light when forming the next modified layer M3. And, by not stopping the rotation of the chuck 100 as described above, the waiting time for the irradiation of the laser light during the rotation acceleration and deceleration of the chuck 100 can be shortened, and the overall processing time can be shortened. Furthermore, by maintaining the rotation speed of the chuck 100 constant, the laser processing can be performed uniformly, and it is also possible to make the horizontal pitch of the modified layer M uniform.

[0092] In the processing method shown in FIG. 15(b), while rotating the chuck 100 by the rotating mechanism 102, the inside of the processing target wafer W is irradiated with laser light from the laser head 103 fixed in the vertical direction to form an annular modified layer M4. Before the formation of the modified layer M4 is completed, while continuing the rotation of the chuck 100 and the irradiation of the laser light from the laser head 103, the lifting mechanism 105 raises the laser head 103 to a predetermined position, that is, a position where the modified layer M3 is to be formed. Thereafter, while fixing the vertical position of the laser head 103, while rotating the chuck 100, the laser head 103 irradiates with laser light to form an annular modified layer M3. The modified layers M2 and M1 are formed in the same manner to form modified layers M1 to M4 on the processing target wafer W. In this case, since the modified layers M1 to M4 can be formed continuously, the time required for processing can be shortened compared to the processing method shown in FIG. 15(a).

[0093] In the processing method shown in FIG. 15(c), while rotating the chuck 100 by the rotating mechanism 102 and raising the laser head 103 by the lifting mechanism 105, the laser head 103 irradiates the inside of the processing target wafer W with laser light, thereby continuously forming annular modified layers M1-M4. That is, in this processing method, the modified layers M1-M4 are continuously formed in a spiral shape. Even in this case, since the modified layers M1-M4 can be continuously formed, the time required for processing can be shortened compared to the processing method shown in FIG. 15(a). Moreover, the modified layers M1-M4 are not formed with a steep gradient in side view, and can be formed uniformly in the vertical direction (thickness direction of the processing target wafer W) compared to the processing method shown in FIG. 15(b).

[0094] In the above embodiment, the modified layer forming apparatus 31 forms an annular modified layer M inside the processing target wafer W, but as shown in Fig. 16, a plurality of radial modified layers M' may be further formed extending radially outward from the annular modified layer M. In such a case, for example, when removing the peripheral edge portion We by the processing apparatus 32, the peripheral edge portion We is peeled off from the annular modified layer M as a base point and divided into a plurality of portions by the radial modified layers M'. In this way, the peripheral edge portion We to be removed becomes smaller, and can be removed more easily.

[0095] In addition, as a method of dividing the peripheral portion We (edge ​​piece) to be removed during grinding of the processing surface Wg into smaller pieces, multiple annular divided modified layers M" may be formed at any intervals concentrically with the modified layer M, as shown in Figure 16. In such a case, the peripheral portion We to be removed can be made smaller. Furthermore, by controlling the radial intervals of the divided modified layers M", the size of the small pieces of the peripheral portion We to be removed can be controlled.

[0096] Furthermore, when forming multiple annular divided modified layers M" in this manner, the divided modified layers M" may be formed in a spiral shape when viewed in a plane, as shown in FIG. 17. In such a case, in the modified layer forming device 31, the chuck 100 or the laser head 103 is moved horizontally while the chuck 100 is rotated and laser light is irradiated from the laser head 103 to the processed wafer W, thereby continuously forming spiral divided modified layers M". As a result, the time required for processing can be shortened.

[0097] Also, as shown in FIG. 18, the divided modified layer M" may be formed in a spiral and meandering shape in plan view. In such a case, in the modified layer forming device 31, the chuck 100 or the laser head 103 is moved in the horizontal direction while the chuck 100 is rotated and the laser head 103 irradiates the processed wafer W with laser light. At this time, by controlling the phase, period and amplitude of the movement of the chuck 100 or the laser head 103, such a meandering wave-shaped divided modified layer M" can be formed. Moreover, this divided modified layer M" is formed two or more times. Then, by controlling the shift in the meandering phase and the number of revolutions of the divided modified layer M", the size of the small pieces of the peripheral portion We to be removed can be controlled. In this embodiment, the radial modified layer M' shown in FIG. 16 and FIG. 17 is not necessary.

[0098] Also, as shown in FIG. 19(a), the divided modified layer M″ may be formed so that the crack C developing from the divided modified layer M″ extends to a predetermined position inside the wafer W to be processed. That is, the crack C reaches the non-processed surface Wn of the wafer W to be processed, but does not reach the processed surface Wg. In such a case, for example, when the grinding wheel 112 is lowered in the processing device 32 to grind the processed surface Wg, the processed surface Wg is ground including the peripheral portion We of the wafer W to be processed, as shown in FIG. 19(b), until the grinding surface of the grinding wheel 112 reaches the crack C. Then, when the grinding surface of the grinding wheel 112 reaches the crack C, the peripheral portion We is peeled off and removed below the crack C. By controlling the upper end height of the crack C to a predetermined position in this manner, the size (height) of the small piece of the peripheral portion We to be removed can be controlled. In the example of Figure 19, the divided modified layer M" is formed in two stages, but by adjusting the focal point from the laser head 103 to two, it is also possible to simultaneously form two stages of divided modified layer M" while rotating the chuck 100.

[0099] In the above embodiment, the following method may be used as a method for efficiently removing the peripheral edge We. That is, for example, before bonding the processing target wafer W and the support wafer S in the bonding apparatus 30, the peripheral edge We can be efficiently removed by reducing the bonding force at the interface between the processing target wafer W and the support wafer S in a portion corresponding to the peripheral edge We to be removed. The following method is a specific example of the method for reducing the bonding force.

[0100] The first bonding strength reducing method is to roughen the non-processed surface Wn of the processing target wafer W, which corresponds to the peripheral edge We to be removed, by irradiating it with a laser beam or the like. Specifically, an interface processing device 300 shown in Fig. 20 is used. The interface processing device 300 is provided at an arbitrary position in the processing station 3 of the substrate processing system 1, for example.

[0101] The interface processing apparatus 300 has a chuck 301 that holds the processing target wafer W with the non-processing surface Wn facing upward. The chuck 301 is configured to be movable in the X-axis direction and the Y-axis direction by a moving mechanism 302. The moving mechanism 302 is configured as a general precision XY stage. In addition, the chuck 301 is configured to be rotatable about a vertical axis by a rotating mechanism 303.

[0102] A laser head 304 is provided above the chuck 301, which irradiates a non-processing surface Wn in the peripheral portion We of the processing target wafer W with laser light K. Any type of laser light K may be irradiated from the laser head 304, and may be, for example, an excimer laser or a fiber laser. As described above, the device layer D and the oxide film Fw are formed on the non-processing surface Wn, and the laser light may have a wavelength that is absorbed by the oxide film Fw, for example, 266 nm. The laser head 304 may be configured to be movable in the X-axis, Y-axis, and Z-axis directions by a moving mechanism (not shown).

[0103] The irradiation port of the laser head 304 for the laser light K is configured to be movable in the horizontal direction by a moving mechanism (not shown). The moving mechanism may, for example, mechanically move the irradiation port of the laser head 304, or may move the irradiation port by an acoustic element. Since the laser light is absorbed by the oxide film Fw, it is not necessary to strictly control the focal point. For this reason, as in this embodiment, the irradiation port of the laser head 304 is moved by the moving mechanism to modify and roughen the non-processed surface Wn (oxide film Fw) in the peripheral portion We.

[0104] A gas supply unit 305 is provided above the chuck 301 to supply gas to the wafer W to be processed. The gas supplied from the gas supply unit 305 may be, for example, clean air or an inert gas such as nitrogen gas. The gas supply unit 305 has a nozzle 306 for supplying gas and a rectifying plate 307 for rectifying the gas supplied from the nozzle 306. The nozzle 306 is connected to a gas supply source (not shown) that stores and supplies gas. The gas supply port of the nozzle 306 is formed above the center of the wafer W to be processed. The rectifying plate 307 is provided approximately parallel to the wafer W to be processed held by the chuck 301, and controls the gas from the nozzle 306 to flow over the non-processing surface Wn of the wafer W to be processed.

[0105] A cup 308 for collecting and discharging gas from a gas supply unit 305 is provided around the chuck 301. An exhaust pipe 309 for discharging gas is connected to the bottom surface of the cup 308. The cup 308 may cover the entire circumference of the wafer W to be processed, or may cover only the periphery of the laser head 304 locally.

[0106] In the interface processing apparatus 300, first, the processing target wafer W is held by the chuck 301, and then the chuck 301 is moved in the horizontal direction by the moving mechanism 302 to center the processing target wafer W. Thereafter, while the chuck 301 is rotated by the rotating mechanism 303, the laser head 304 irradiates the non-processed surface Wn in the peripheral portion We of the processing target wafer W with laser light K to roughen the non-processed surface Wn.

[0107] When the non-processed surface Wn is roughened, gas is supplied from the gas supply unit 305 to the non-processed surface Wn of the wafer W to be processed. The supplied gas flows over the entire surface of the non-processed surface Wn and is exhausted from the exhaust pipe 309. When the non-processed surface Wn in the peripheral portion We is modified using a laser beam as in this embodiment, debris (dust) may be generated. If this debris adheres to the non-processed surface Wn in the central portion Wc, the device may be damaged. Therefore, by supplying gas from the gas supply unit 305 and purging, it is possible to suppress the debris from adhering to the non-processed surface Wn. Note that after the interface processing in the interface processing device 300, the non-processed surface Wn may be cleaned in another cleaning device (not shown). In this case, compared to a case where there is no configuration for supplying gas between the rectifying plate 307 and the wafer W to be processed as in the interface processing device 300, for example, cleaning in the interface processing device 300 in this embodiment can be suppressed to a lighter level.

[0108] At the position where the non-processed surface Wn is to be roughened, as shown in FIG. 21, for example, the boundary between the non-processed surface Wn of the processed wafer W corresponding to the peripheral portion We to be removed and the non-processed surface Wn of the processed wafer W corresponding to the central portion Wc not to be removed may be modified to form a modified groove R1 as a bonding strength reducing portion for reducing the bonding strength. Furthermore, a plurality of annular modified grooves R2 may be formed outside the modified groove R1. Alternatively, as shown in FIG. 22, the portion corresponding to the peripheral portion We may be modified in a planar manner to form a rough modified surface R3. In such a case, the modified surface R3 may be formed by a plurality of modified grooves R2, or the modified surface R3 may be formed by adjusting the irradiation range of the laser light.

[0109] Next, a description will be given of wafer processing performed using the substrate processing system 1 provided with the above-described interface processing apparatus 300. Note that in this embodiment, detailed descriptions of processes similar to those in the first embodiment will be omitted.

[0110] First, the wafer W to be processed is taken out of the cassette Cw by the wafer transfer device 22 and transferred to the interface processing device 300. In the interface processing device 300, the non-processed surface Wn (oxide film Fw) in the peripheral portion We of the wafer W to be processed is modified to form any one of the roughened modified grooves R1, R2, or modified surface R3, as shown in FIG. 23(a).

[0111] In parallel with the roughening of the non-processed surface Wn in the interface processing device 300 , the support wafer S in the cassette Cs is removed by the wafer transfer device 22 and transferred to the bonding device 30 .

[0112] Next, the processing target wafer W is transferred to the bonding device 30 by the wafer transfer device 22. At this time, the processing target wafer W is turned over by the wafer transfer device 22 or an inversion device (not shown). In the bonding device 30, the processing target wafer W and the support wafer S are bonded together to form an overlapped wafer T, as shown in FIG. 23(b).

[0113] Next, the overlapped wafer T is transported by the wafer transport device 22 to the modified layer forming device 31. In the modified layer forming device 31, a modified layer M is formed at a predetermined position inside the processing target wafer W, as shown in Fig. 23(c). That is, the modified layer M is formed corresponding to the modified grooves R1, R2 and the modified surface R3.

[0114] Next, the overlapped wafer T is transported by the wafer transport device 22 to the processing device 32. In the processing device 32, the processing surface Wg of the processing wafer W is ground to a target thickness as shown in Fig. 23(d). As the grinding of the processing surface Wg proceeds, the peripheral portion We of the processing wafer W is peeled off and removed from the modified layer M and the crack C as shown in Fig. 23(e). At this time, since the interface (non-processed surface Wn) between the processing wafer W and the support wafer S is roughened and the bonding force is reduced, the peripheral portion We can be appropriately removed.

[0115] Thereafter, the laminated wafer T on which all the processes have been performed is transferred by the wafer transfer device 22 to the cassette Ct on the cassette mounting table 10. In this manner, a series of wafer processing steps in the substrate processing system 1 is completed.

[0116] In this embodiment, after forming any one of the modified grooves R1, R2, or modified surface R3 on the processing wafer W as shown in FIG. 23(a), the processing wafer W and the support wafer S are bonded as shown in FIG. 23(b), and further, the modified layer M is formed on the processing wafer W as shown in FIG. 23(c), but the order of these steps is not limited. For example, the formation of the modified grooves R1, R2, and modified surface R3, the formation of the modified layer M, and the bonding of the wafers W and S may be performed in this order. Also, for example, the formation of the modified layer M, the formation of the modified grooves R1, R2, and modified surface R3, and the bonding of the wafers W and S may be performed in this order. Furthermore, for example, the formation of the modified layer M, the bonding of the wafers W and S, the formation of the modified grooves R1, R2, and modified surface R3 may be performed in this order.

[0117] In the present embodiment, the interface treatment device 300 is provided separately from the modified layer forming device 31, but the interface treatment device 300 and the modified layer forming device 31 may be the same device. In such a case, for example, the modified layer forming device 31 is provided with a laser head 304.

[0118] Alternatively, a protective film may be formed on the non-processing surface Wn prior to the laser processing in the interface processing device 300. In such a case, the processing station 3 of the substrate processing system 1 is provided with a coating device (not shown) for forming the protective film and a cleaning device (not shown) for cleaning the protective film. The coating device applies a protective material to the entire surface of the non-processing surface Wn by, for example, spin coating, to form the protective film. The cleaning device supplies a cleaning liquid to the entire surface of the non-processing surface Wn by, for example, spin cleaning, to clean and remove the protective film.

[0119] In the substrate processing system 1, first, a protective film is formed on the entire non-processing surface Wn in a coating device. Then, in an interface processing device 300, the non-processing surface Wn at the peripheral portion We is modified as shown in FIG. 23(a). At this time, since a protective film is formed on the central portion Wc of the processing target wafer W, even if debris is generated by the laser light, damage to the device can be suppressed. Then, if the protective film on the non-processing surface Wn is cleaned and removed in a cleaning device, the processing target wafer W and the support wafer S can be bonded thereto as shown in FIG. 23(b).

[0120] The second bonding strength reducing method is to form a release film by applying a release agent to the non-processed surface Wn of the processing target wafer W in a portion corresponding to the peripheral edge We to be removed. Specifically, for example, an interface processing device 310 shown in Fig. 24 is used. The interface processing device 310 is provided at an arbitrary position in the processing station 3 of the substrate processing system 1.

[0121] The interface processing apparatus 310 has a chuck 311 that holds the processing target wafer W with the non-processing surface Wn facing upward. The chuck 311 is configured to be rotatable about a vertical axis by a rotation mechanism 312.

[0122] A nozzle 313 is provided above the chuck 311 to apply a release agent A to a non-processing surface Wn in the peripheral portion We of the processing target wafer W. The nozzle 313 is connected to a release agent supply source (not shown) that stores and supplies the release agent A. The nozzle 313 may be configured to be movable in the X-axis direction, the Y-axis direction, and the Z-axis direction by a moving mechanism (not shown). The release agent A may be made of any material that reduces the bonding force at the interface between the processing target wafer W and the support wafer S.

[0123] The wafer processing method performed using the substrate processing system 1 provided with the above-described interface processing device 310 is the same as the method shown in Fig. 23 except that the laser processing in the interface processing device 300 is replaced with a release agent application process in the interface processing device 310. In the interface processing device 310, a release agent A is applied from a nozzle 313 to the non-processed surface Wn of the peripheral portion We while rotating a chuck 311, thereby forming a release film on the non-processed surface Wn. Then, since the bonding strength between the processed wafer W and the support wafer S is reduced by the release film at the peripheral portion We, the peripheral portion We can be appropriately removed in Fig. 23(e).

[0124] When the rotation speed of the chuck 311 in the interface processing device 310 is high, the applied release agent A is thrown off to the outside of the processing target wafer W by centrifugal force. On the other hand, when the rotation speed of the chuck 311 is medium, there is a risk that the release agent A will get around to the processing surface Wg of the processing target wafer W. Therefore, a rinse liquid of the release agent A may be supplied from the processing surface Wg side. When the rotation speed of the chuck 311 is low, the release agent A may be sucked and discharged from the outside of the processing target wafer W.

[0125] The third method for reducing the bonding strength is to thinly etch the non-processed surface Wn of the processed wafer W, which corresponds to the peripheral edge We to be removed, with a chemical solution or the like. For example, in the case of a TEOS film, etching is performed with hydrofluoric acid. The interface processing device for this etching may be configured as desired, and a known etching device may be used.

[0126] In this embodiment, instead of the laser processing of the interface processing apparatus 300 shown in Fig. 23(a), an etching process is performed on the peripheral portion We. The etched peripheral portion We is removed to form a step between the peripheral portion We and the central portion Wc, or the etched peripheral portion We is roughened. Then, when the processing target wafer W and the support wafer S are bonded by the bonding apparatus 30 as shown in Fig. 23(b), the processing target wafer W and the support wafer S are not bonded at the peripheral portion We. Therefore, the peripheral portion We can be appropriately removed in Fig. 23(e).

[0127] The fourth method for reducing the bonding strength is to irradiate the non-processed surface Wn of the processing target wafer W, which corresponds to the peripheral portion We to be removed, with plasma during bonding, for example when the bonding apparatus 30 is a bonding apparatus that utilizes plasma as described above. As described above, in the bonding apparatus 30, oxygen ions or nitrogen ions converted into plasma are irradiated onto the non-processed surface Wn, so that the non-processed surface Wn is plasma-processed and activated. Therefore, in this bonding apparatus 30, a shielding plate may be provided above the non-processed surface Wn in the peripheral portion We to prevent the non-processed surface Wn from being irradiated with oxygen ions or nitrogen ions.

[0128] In such a case, in the bonding apparatus 30, the non-processed surface Wn in the central portion Wc of the processing target wafer W is activated by oxygen ions or nitrogen ions, but the non-processed surface Wn in the peripheral portion We is not activated. Then, when the processing target wafer W and the support wafer S are bonded to each other in the bonding apparatus 30 as shown in Fig. 23(b), the processing target wafer W and the support wafer S are not bonded to each other at the peripheral portion We. For this reason, the peripheral portion We can be appropriately removed in Fig. 23(e).

[0129] In the above embodiment, the four processes described above were performed on the non-processing surface Wn of the processing target wafer W before bonding to reduce the bonding force, but similar processes may also be performed on the bonding surface Sj of the support wafer S.

[0130] In the above embodiment, as a method for efficiently removing the peripheral edge We, after bonding the processing target wafer W and the supporting wafer S by the bonding apparatus 30, the peripheral edge We can be efficiently removed by reducing the bonding force at the interface between the processing target wafer W and the supporting wafer S in a portion corresponding to the peripheral edge We to be removed. As a specific example of the method for reducing the bonding force, the following method can be considered.

[0131] For example, laser light is transmitted to the non-processing surface Wn of the processing target wafer W to cause ablation at each interface. Specifically, for example, a processing device 320 shown in Fig. 25 is used. The processing device 320 is provided in place of the modified layer forming device 31 in the processing station 3 of the substrate processing system 1, for example.

[0132] The processing device 320 further includes a laser head 321, a moving mechanism 322, and a lifting mechanism 323 in the configuration of the modified layer forming device 31. The laser head 321 irradiates the non-processed surface Wn with laser light to modify it. The laser head 321 irradiates the non-processed surface Wn with high-frequency pulsed laser light oscillated from a laser light oscillator (not shown), which has a wavelength that is transparent to the processed wafer W, at a predetermined position inside the processed wafer W. As a result, the portion inside the processed wafer W where the laser light is focused is modified. The moving mechanism 322 moves the laser head 321 in the X-axis direction and the Y-axis direction. The moving mechanism 322 is composed of a general precision XY stage. The lifting mechanism 323 moves the laser head 321 in the Z-axis direction. As described above, the processing device 320 serves both as a modified layer forming device and an interface processing device.

[0133] When the processing apparatus 320 processes the interface between the processing target wafer W and the support wafer S, the inside of the processing target wafer W or the inside of the device layer D is modified. That is, the interface in this embodiment includes the inside of the processing target wafer W and the inside of the device layer D.

[0134] When modifying the inside of the wafer W to be processed as shown in FIG. 26, a modified surface R4 is formed in the vicinity of the non-processed surface Wn in the peripheral portion We (outside the modified layer M). In this processing method, as shown in FIG. 27, a laser beam L is irradiated from a laser head 321 toward the inside of the wafer W to be processed. The laser beam L passes through the inside of the wafer W to be processed and is condensed, and the condensed portion is modified. Then, while rotating the chuck 100 by the rotating mechanism 102, the laser head 321 is moved radially outward by the moving mechanism 322, and the laser beam L is irradiated from the laser head 321 to the inside of the wafer W to be processed. In this way, the modified surface R4 is formed. When forming the modified surface R4, the chuck 100 may be moved radially by the moving mechanism 101, or both the laser head 321 and the chuck 100 may be moved.

[0135] In this manner, when forming the modified surface R4 inside the processing target wafer W, after removing the peripheral edge portion We, a part of the processing target wafer W remains on the supporting wafer S. For this reason, after removing the peripheral edge portion We, this remaining part of the processing target wafer W may be removed by etching.

[0136] 28, when the inside of the device layer D is modified, a modified surface R5 is formed in the peripheral portion We (outside the modified layer M) inside the device layer D. There are three processing methods for this, for example, as shown in FIG.

[0137] The first processing method is a method in which the focal point of the laser light L from the laser head 321 is positioned inside the wafer W and above the device layer D, as shown in FIG. 29(a). In this case, the energy of the laser light L is reduced to such an extent that the wafer W is not modified even if the laser light L is focused. Then, the laser light L is once focused inside the wafer W, but the laser light L that is further defocused and spreads passes through the wafer W and is irradiated to the device layer D. The laser light L is absorbed by the device layer D, and the device layer D causes ablation. Then, the laser head 321 is irradiated from the laser head 321 while the chuck 100 is rotated by the rotation mechanism 102 and the laser head 321 is moved radially outward by the movement mechanism 322. Then, a modified surface R5 is formed on the device layer D. When forming the modified surface R5, the chuck 100 may be moved in the radial direction by the moving mechanism 101, or both the laser head 321 and the chuck 100 may be moved.

[0138] The second processing method is a method in which the focal point of the laser light L from the laser head 321 is positioned inside the device layer D as shown in FIG. 29(b). In this case, the laser light L is transmitted through the processed wafer W and irradiated onto the device layer D, causing ablation of the device layer D. Then, the laser head 321 irradiates the laser light L while rotating the chuck 100 by the rotation mechanism 102 and moving the laser head 321 radially outward by the movement mechanism 322. Then, a modified surface R5 is formed on the device layer D. Note that when forming the modified surface R5, the chuck 100 may be moved radially by the movement mechanism 101, or both the laser head 321 and the chuck 100 may be moved.

[0139] The third processing method is a method in which the focal point of the laser light L from the laser head 321 is positioned below the device layer D as shown in FIG. 29(c). In this case, the laser light L passes through the processed wafer W and is irradiated to the device layer D, causing ablation of the device layer D. Since the laser light L is absorbed by the device layer D, it is not focused below the device layer D. Then, the laser head 321 irradiates the laser light L while rotating the chuck 100 by the rotation mechanism 102 and moving the laser head 321 radially outward by the movement mechanism 322. Then, a modified surface R5 is formed on the device layer D. When forming the modified surface R5, the chuck 100 may be moved radially by the movement mechanism 101, or both the laser head 321 and the chuck 100 may be moved.

[0140] When forming the modified surface R5 on the device layer D, the influence of ablation in the device layer D at the peripheral portion We may extend to the device layer D at the central portion Wc inside. Therefore, it is preferable to form the modified surface R5 after forming the modified layer M4 on the device layer D as shown in Fig. 14(d). In such a case, the modified layer M4 serves to block the influence of ablation, and the influence of the ablation can be reliably prevented from extending to the central portion Wc.

[0141] Next, a description will be given of wafer processing performed using the substrate processing system 1 provided with the above-described processing apparatus 320. Note that in this embodiment, detailed descriptions of processes similar to those in the first embodiment will be omitted.

[0142] First, the wafer W to be processed is taken out of the cassette Cw by the wafer transfer device 22 and transferred to the bonding device 30. Subsequently, the support wafer S is also taken out of the cassette Cs by the wafer transfer device 22 and transferred to the bonding device 30. In the bonding device 30, the wafer W to be processed and the support wafer S are bonded together to form an overlapped wafer T, as shown in Fig. 30(a).

[0143] Next, the overlapped wafer T is transferred to the processing device 320 by the wafer transfer device 22. In the processing device 320, the laser head 103 is moved to above the peripheral portion We. Then, while rotating the chuck 100, the laser head 103 irradiates the inside of the processing target wafer W with laser light, and a modified layer M is formed at a predetermined position inside the processing target wafer W as shown in FIG. 30(b).

[0144] Next, in the processing device 320, the laser head 103 is withdrawn and the laser head 321 is moved above the peripheral portion We. Then, while rotating the chuck 100, the laser head 321 is moved radially outward while irradiating the laser light from the laser head 321. Then, as shown in FIG. 30(c), a modified surface R4 or R5 is formed inside the processed wafer W or on the device layer D, respectively.

[0145] The order of forming the modified layer M shown in FIG. 30(b) and the forming of the modified surface R4 or R5 shown in FIG. 30(c) may be reversed.

[0146] Next, the overlapped wafer T is transported by the wafer transport device 22 to the processing device 32. In the processing device 32, the processing surface Wg of the processing wafer W is ground to a target thickness as shown in Fig. 30(d). As the grinding of the processing surface Wg proceeds, the peripheral portion We of the processing wafer W is peeled off and removed from the modified layer M and the crack C as shown in Fig. 30(e). At this time, since the modified surface R4 or R5 is formed at the interface between the processing wafer W and the support wafer S and the bonding force is reduced, the peripheral portion We can be appropriately removed.

[0147] Thereafter, the laminated wafer T on which all the processes have been performed is transferred by the wafer transfer device 22 to the cassette Ct on the cassette mounting table 10. In this manner, a series of wafer processing steps in the substrate processing system 1 is completed.

[0148] In this embodiment, the same effects as those of the first and second embodiments can be obtained. Moreover, in the processing apparatus 320, the modified layer M and the modified surface R4 or R5 are formed using the same chuck 100, so the processed wafer W is not decentered in the processing by the laser head 103 and the processing by the laser head 321. As a result, the position of the modified layer M can be aligned with the inner peripheral position of the modified surface R4 or R5, and the peripheral portion We can be more appropriately removed.

[0149] In the processing device 320, the laser head 103 and the laser head 321 do not need to be provided separately, and may be a common head. Also, the laser head 103 and the laser head 321 in the processing device 320 may be provided in different devices, or may be provided in the modified layer forming device 31 and the interface processing device, respectively.

[0150] 12, this embodiment can also be applied to the case where a second processed wafer W2 is further stacked on the overlapped wafer T. In this case, if the position of the peripheral portion We to be removed of the second processed wafer W2 coincides with the position of the overlapped wafer T, the formation of the modified surface R4 or R5 can be omitted.

[0151] This embodiment can also be applied to the case where the peripheral edge We to be removed of the upper second processed wafer W2 is located inside the peripheral edge We to be removed of the lower first processed wafer W1 as shown in Fig. 13. In this case, however, it is preferable that the modified surface R4 or R5 is formed on the peripheral edge We of the second processed wafer W2 to be removed from the first processed wafer W1.

[0152] In the above embodiments, it is preferable that the position of the modified groove R1 formed on the processed wafer W before bonding, the inner peripheral position of the modified surface R3, or the inner peripheral positions of the modified surfaces R4 and R5 formed on the processed wafer W after bonding, all coincide with the position of the modified layer M.

[0153] To explain the reason for this, as an example, Fig. 31 shows a case where the processed wafer W is eccentrically bonded to the overlapped wafer T, and the position of the modified layer M is misaligned with the inner peripheral position of the modified surface R4. In this case, as shown in Fig. 31, there are places where the modified layer M is located radially inward from the inner peripheral position of the modified surface R4, and places where the modified layer M is located radially outward from the inner peripheral position of the modified surface R4.

[0154] When the modified layer M is located radially inward from the inner circumference of the modified surface R4 as shown in Fig. 32(a), when the processing surface Wg of the processing target wafer W is ground to remove the peripheral portion We as shown in Fig. 32(b), the width D1 of the removed peripheral portion may be smaller than the target width D2 of the peripheral portion We to be removed. In addition, since the removed peripheral portion peels off without passing through the modified layer M and the crack C, the outer surface of the processing target wafer W after the peripheral portion is removed may become rough.

[0155] Furthermore, even if the modified layer M is located radially inward from the inner circumference of the modified surface R4, if the distance between the modified layer M and the inner circumference of the modified surface R4 is sufficiently small, the bonding force between the processed wafer W and the support wafer S becomes sufficiently small so that the peripheral portion We can be removed.

[0156] When the modified layer M is located radially outward from the inner circumference of the modified surface R4 as shown in Fig. 33(a), when the processing surface Wg of the processed wafer W is ground to remove the peripheral portion We as shown in Fig. 33(b), the modified surface R4 remains between the processed wafer W and the device layer D. In the area where this modified surface R4 is present, the processed wafer W and the device layer D may peel off from each other, which may cause chipping.

[0157] There are two possible methods for eliminating such a misalignment between the position of the modified layer M and the inner peripheral position of the modified surface R4. The first method for eliminating the misalignment is to detect the eccentricity of the processed wafer W in the overlapped wafer T, and adjust the position of the modified layer M or the inner peripheral position of the modified surface R4 based on the detection results. The second method for eliminating the misalignment is to detect the position of the modified layer M or the inner peripheral position of the modified surface R4, and adjust the position of the modified surface R4 or the modified layer M formed in the subsequent process based on the detection results.

[0158] When performing the above-mentioned two misalignment eliminating methods, for example, a processing device 330 shown in Fig. 34 is used. The processing device 330 is provided, for example, in the processing station 3 of the substrate processing system 1 in place of the processing device 320. The processing device 330 has the same configuration as the processing device 320, but has an eccentricity detection unit 331 for performing the first misalignment eliminating method and a position detection unit 332 for performing the second misalignment eliminating method.

[0159] The first method of eliminating the misalignment will be described. The eccentricity detection unit 331 is disposed above the center of the chuck 100. The eccentricity detection unit 331 is configured to be movable in the X-axis direction, the Y-axis direction, and the Z-axis direction by a moving mechanism (not shown). The eccentricity detection unit 331 has, for example, a CCD camera. The eccentricity detection unit 331 captures an image of the overlapped wafer T held by the chuck 100, specifically, at least three points on the outer periphery. The eccentricity detection unit 331 detects the misalignment of the center of the processed wafer W with respect to the rotation center of the chuck 100, that is, the eccentricity of the processed wafer W in the overlapped wafer T. The configuration of the eccentricity detection unit 331 is not limited to this embodiment, and may have, for example, an IR camera. In this case, the eccentricity detection unit 331 captures an image of an alignment mark formed on the processed wafer W, for example, to detect the eccentricity of the processed wafer W in the overlapped wafer T.

[0160] The first method for eliminating the misalignment is performed using the detection result from the eccentricity detection unit 331. Here, a description will be given of the case where the wafer processing shown in FIG.

[0161] 30(a), the processing target wafer W and the support wafer S are bonded to form an overlapped wafer T. Next, the overlapped wafer T is transferred to the processing device 330. In the processing device 330, the overlapped wafer T is held by the chuck 100, and then an image of the overlapped wafer T is captured by the eccentricity detection unit 331, and the eccentricity of the processing target wafer W in the overlapped wafer T is detected. The detection result of the eccentricity detection unit 331 is output to the control device 40.

[0162] The control device 40 adjusts the central axis of the chuck 100, the irradiation axis of the laser light irradiated from the laser head 103, or the irradiation axis of the laser light irradiated from the laser head 321 based on the detection result of the eccentricity detection unit 331, i.e., the eccentricity of the processed wafer W. By adjusting the central axis of the chuck 100 or the irradiation axis of the laser head 103, it is possible to properly form a modified layer M on the processed wafer W as shown in Fig. 30(b). In addition, by adjusting the central axis of the chuck 100 or the irradiation axis of the laser head 321, it is possible to properly form a modified surface R4 on the processed wafer W as shown in Fig. 30(c).

[0163] As described above, by adjusting the central axis of the chuck 100, the irradiation axis of the laser head 103, or the irradiation axis of the laser head 321 based on the detection result of the eccentricity of the processed wafer W by the eccentricity detection unit 331, the position of the modified layer M can be aligned with the inner peripheral position of the modified surface R4.

[0164] The eccentricity detection unit 331 may be provided in an eccentricity detection device (not shown) outside the processing device 320. In this case, when the overlapped wafer T is transferred from the eccentricity detection device to the processing device 320 by the wafer transfer device 22, the overlapped wafer T is transferred so that the center of the processing target wafer W and the center of the chuck 100 coincide with each other based on the detection result of the eccentricity of the processing target wafer W by the eccentricity detection unit 331. In this way, the modified layer M can be appropriately formed on the processing target wafer W as shown in FIG. 30(b), and the modified surface R4 can be appropriately formed inside the processing target wafer W or in the device layer as shown in FIG. 30(c). Therefore, the position of the modified layer M can be aligned with the inner peripheral position of the modified surface R4.

[0165] Furthermore, the eccentricity detection unit 331 may detect the eccentricity of the second processed wafer W2 that is further stacked and bonded to the overlapped wafer T. Even in this case, the position of the modified layer M can be aligned with the inner peripheral position of the modified surface R4 based on the detection result of the eccentricity of the second processed wafer W2 with respect to the overlapped wafer T.

[0166] The second method of eliminating misalignment will be described. The position detection unit 332 is disposed above the outer periphery of the chuck 100. The position detection unit 332 is configured to be movable in the X-axis direction, the Y-axis direction, and the Z-axis direction by a moving mechanism (not shown). For example, an IR camera using infrared rays is used as the position detection unit 332. The position detection unit 332 detects the position of the modified layer M formed on the processing target wafer W or the inner peripheral position of the modified surface R4 for the overlapped wafer T held by the chuck 100.

[0167] The second method for eliminating the misalignment is performed using the detection result in the position detection unit 332. Here, a description will be given of the case where the wafer processing shown in FIG.

[0168] First, in the bonding apparatus 30, the processing target wafer W and the support wafer S are bonded as shown in Fig. 30(a) to form an overlapped wafer T. Next, the overlapped wafer T is transferred to the processing apparatus 330. In the processing apparatus 330, a modified layer M is formed on the processing target wafer W using the laser head 103 as shown in Fig. 30(b).

[0169] When a modified layer M is formed on the processing target wafer W, the position detection unit 332 uses infrared rays to image the modified layer M inside the processing target wafer W, and detects the position of the modified layer M. The detection result of the position detection unit 332 is output to the control device 40.

[0170] The control device 40 adjusts the central axis of the chuck 100 or the irradiation axis of the laser head 321 based on the detection result of the position detection unit 332, i.e., the position of the modified layer M. This makes it possible to properly form the modified surface R4 on the processing target wafer W, as shown in Fig. 30(c). As a result, it is possible to make the position of the modified layer M coincide with the inner peripheral position of the modified surface R4.

[0171] 30(b) and the formation of the modified layer M shown in FIG. 30(c) may be performed in the reverse order. In such a case, after the modified surface R4 is formed on the processing target wafer W, the position detection unit 332 captures an image of the modified surface R4 using infrared rays, and detects the inner peripheral position of the modified surface R4. The detection result of the position detection unit 332 is output to the control device 40.

[0172] The control device 40 adjusts the central axis of the chuck 100 or the irradiation axis of the laser head 103 based on the detection result of the position detection unit 332, i.e., the inner peripheral position of the modified surface R4. This makes it possible to appropriately form the modified layer M on the processing target wafer W. As a result, it is possible to make the position of the modified layer M coincide with the inner peripheral position of the modified surface R4.

[0173] Furthermore, in the above embodiment, the position detection unit 332 detects the position of the modified layer M or the inner peripheral position of the modified surface R4 formed on the processing target wafer W after bonding, but it may also detect the position of the modified layer M or the inner peripheral position of the modified surface R4 formed on the processing target wafer W before bonding. Even in such a case, the modified surface R4 or the modified layer M can be appropriately formed after detection by the position detection unit 332, so that the position of the modified layer M and the inner peripheral position of the modified surface R4 coincide with each other.

[0174] In short, regardless of whether the formation of the modified layer M or the formation of the modified surface R4 is performed first, the position of the modified layer M or the inner position of the modified surface R4 can be detected by the position detection unit 332, and the modified surface R4 or the modified layer M can then be appropriately formed, and the position of the modified layer M can be aligned with the inner position of the modified surface R4.

[0175] Next, a substrate processing system according to a third embodiment of the present invention will be described below. Fig. 35 is a plan view showing a schematic configuration of a substrate processing system 400 according to the third embodiment.

[0176] The substrate processing system 400 has a configuration in which, for example, a loading / unloading station 401 through which a cassette Ct capable of housing multiple overlapping wafers T is loaded and unloaded between the system and the outside, and a processing station 402 equipped with various processing devices that perform predetermined processing on the overlapping wafers T are integrally connected.

[0177] The loading / unloading station 401 is provided with a cassette placement stage 410. In the illustrated example, a plurality of cassettes Ct, for example, four cassettes Ct, can be placed in a line in the Y-axis direction on the cassette placement stage 410. The number of cassettes Ct placed on the cassette placement stage 410 is not limited to the present embodiment and can be determined arbitrarily.

[0178] The loading / unloading station 401 is provided with a wafer transfer area 420 adjacent to the cassette placement table 410. The wafer transfer area 420 is provided with a wafer transfer device 422 that is movable on a transfer path 421 extending in the Y-axis direction. The wafer transfer device 422 has, for example, two transfer arms 423, 423 that hold and transfer the overlapped wafer T. Each transfer arm 423 is configured to be movable in the horizontal direction, the vertical direction, around a horizontal axis, and around a vertical axis. The configuration of the transfer arm 423 is not limited to this embodiment, and any configuration may be used.

[0179] The processing station 402 is provided with a wafer transport area 430. The wafer transport area 430 is provided with a wafer transport device 432 that is movable on a transport path 431 extending in the X-axis direction. The wafer transport device 432 is configured to be capable of transporting the overlapped wafer T to a transition device 434, wet etching devices 440 and 441, and a processing device 450, which will be described later. The wafer transport device 432 also has, for example, two transport arms 433, 433 that hold and transport the overlapped wafer T. Each transport arm 433 is configured to be movable in the horizontal direction, the vertical direction, around a horizontal axis, and around a vertical axis. The configuration of the transport arm 433 is not limited to this embodiment, and may have any configuration.

[0180] Between the wafer transfer area 420 and the wafer transfer area 430, a transition device 434 for transferring the overlapped wafer T is provided.

[0181] On the Y-axis positive side of wafer transfer area 430, wet etching devices 440 and 441 are arranged in this order in the X-axis direction from the load / unload station 401 side. In the wet etching devices 440 and 441, wet etching is performed on the processing surface Wg of the processing target wafer W with a chemical solution such as hydrofluoric acid.

[0182] A processing device 450 is disposed on the X-axis positive side of the wafer transfer region 430. In the processing device 450, processing such as grinding and cleaning is performed on the target wafer W. The processing device 450 has a rotating table 460, a transfer unit 470, a processing unit 480, a first cleaning unit 490, a second cleaning unit 500, a rough grinding unit 510, a medium grinding unit 520, and a finish grinding unit 530.

[0183] The turntable 460 is configured to be freely rotatable by a rotation mechanism (not shown). Four chucks 461 that suction-hold the overlapped wafers T are provided on the turntable 460. The chucks 461 are evenly arranged on the same circumference as the turntable 460, that is, at 90 degree intervals. The four chucks 461 are movable to the delivery position A0 and the processing positions A1 to A3 by the rotation of the turntable 460. Furthermore, each of the four chucks 461 is configured to be rotatable around a vertical axis by a rotation mechanism (not shown).

[0184] In this embodiment, the transfer position A0 is a position on the X-axis negative direction side and the Y-axis negative direction side of the rotary table 460, and the second cleaning unit 500, the processing unit 480, and the first cleaning unit 490 are arranged side by side on the X-axis negative direction side of the transfer position A0. The processing unit 480 and the first cleaning unit 490 are arranged in this order from above. The first processing position A1 is a position on the X-axis positive direction side and the Y-axis negative direction side of the rotary table 460, and the rough grinding unit 510 is arranged there. The second processing position A2 is a position on the X-axis positive direction side and the Y-axis positive direction side of the rotary table 460, and the medium grinding unit 520 is arranged there. The third processing position A3 is a position on the X-axis negative direction side and the Y-axis positive direction side of the rotary table 460, and the finish grinding unit 530 is arranged there.

[0185] The transfer unit 470 is an articulated robot equipped with a plurality of, for example, three, arms 471. Each of the three arms 471 is configured to be freely rotatable. A transfer pad 472 that adsorbs and holds the overlapped wafer T is attached to the arm 471 at the tip end. The arm 471 at the base end is attached to a movement mechanism 473 that moves the arm 471 in the vertical direction. The transfer unit 470 having such a configuration can transfer the overlapped wafer T to the delivery position A0, the processing unit 480, the first cleaning unit 490, and the second cleaning unit 500.

[0186] In the processing unit 480, the horizontal orientation of the overlapped wafer T before the grinding process is adjusted. For example, while rotating the overlapped wafer T held by the chuck 100, a detection unit (not shown) detects the position of a notch portion of the processing target wafer W, and adjusts the position of the notch portion to adjust the horizontal orientation of the overlapped wafer T.

[0187] The processing unit 480 has the configuration of the processing device 320, that is, the chuck 100, the moving mechanism 101, the rotating mechanism 102, the laser head 103, the moving mechanism 104, the lifting mechanism 105, the laser head 321, the moving mechanism 322, and the lifting mechanism 323. In the processing unit 480, the laser head 103 forms a modified layer M on the processing target wafer W, and the laser head 321 forms a modified surface R4 or R5 on the processing target wafer W. When the modified layer M is formed on the processing target wafer W in advance, the processing unit 480 forms only the modified surface R4 or R5. Conversely, when the modified surface R4 or R5 is formed on the processing target wafer W in advance, the processing unit 480 forms only the modified layer M.

[0188] In the first cleaning unit 490, the processing surface Wg of the processing target wafer W after the grinding process is cleaned, more specifically, spin-cleaned. For example, while rotating the laminated wafer T held by a spin chuck (not shown), a cleaning liquid is supplied to the processing surface Wg from a cleaning liquid nozzle (not shown). Then, the supplied cleaning liquid spreads over the processing surface Wg, and the processing surface Wg is cleaned.

[0189] In the second cleaning unit 500, the non-bonding surface Sn of the supporting wafer S in a state in which the grinding-processed target wafer W is held on the transfer pad 472 is cleaned, and the transfer pad 472 is also cleaned.

[0190] The rough grinding unit 510 roughly grinds the processing surface Wg of the processing target wafer W. The rough grinding unit 510 has a rough grinding part 511. The rough grinding part 511 has the grinding wheel 112, the spindle 113, and the driving part 114 shown in FIG. 6. The rough grinding part 511 is configured to be movable in the vertical direction and the horizontal direction along the support 512.

[0191] In the medium grinding unit 520, the processing surface Wg of the wafer W to be processed is medium ground. The medium grinding unit 520 has a medium grinding section 521. The medium grinding section 521 has the grinding wheel 112, the spindle 113, and the drive section 114 shown in FIG. 6. The medium grinding section 521 is configured to be movable in the vertical and horizontal directions along the support 522. The grain size of the abrasive grains of the grinding wheel 112 of the medium grinding section 521 is smaller than the grain size of the abrasive grains of the grinding wheel 112 of the rough grinding section 511.

[0192] The finish grinding unit 530 finish-grinds the processing surface Wg of the wafer W. The finish grinding unit 530 has a finish grinding section 531. The finish grinding section 531 has the grinding wheel 112, spindle 113, and drive section 114 shown in FIG. 6. The finish grinding section 531 is configured to be movable vertically and horizontally along the support 532. The grain size of the abrasive grains of the grinding wheel 112 of the finish grinding section 531 is smaller than the grain size of the abrasive grains of the grinding wheel 112 of the intermediate grinding section 521.

[0193] Next, a description will be given of wafer processing performed using the substrate processing system 400 configured as above. In this embodiment, the wafer processing shown in FIG.

[0194] First, a cassette Ct storing a plurality of overlapped wafers T is placed on a cassette placement table 410 of a carry-in / out station 401. In this embodiment, the processing target wafer W and the support wafer S are bonded in a bonding device (not shown) outside the substrate processing system 400 as shown in FIG.

[0195] Next, the overlapped wafer T is taken out of the cassette Ct by the wafer transfer device 422 and transferred to the transition device 434. Subsequently, the overlapped wafer T is taken out of the transition device 434 by the wafer transfer device 432 and transferred to the processing device 450.

[0196] The overlapped wafer T transported to the processing device 450 is delivered to the processing unit 480. In the processing unit 480, a detection unit (not shown) adjusts the horizontal orientation of the processing target wafer W. The processing unit 480 further uses the laser head 103 to form a modified layer M on the processing target wafer W as shown in Fig. 30(b), and then uses the laser head 321 to form a modified surface R4 or R5 on the processing target wafer W as shown in Fig. 30(c).

[0197] Next, the overlapped wafer T is transported by the transport unit 470 from the processing unit 480 to the delivery position A0 and delivered to the chuck 461 at the delivery position A0. After that, the chuck 461 is moved to the first processing position A1. Then, the rough grinding unit 510 roughly grinds the processing surface Wg of the processing target wafer W as shown in FIG. 30(d). Then, as shown in FIG. 30(e), the peripheral portion We of the processing target wafer W is peeled off and removed from the modified layer M and the crack C as base points. At this time, since the modified surface R4 or R5 is formed at the interface between the processing target wafer W and the support wafer S and the bonding force is reduced, the peripheral portion We can be appropriately removed.

[0198] Next, the chuck 461 is moved to the second processing position A2. Then, the processing surface Wg of the wafer W to be processed is medium ground by the medium grinding unit 520. If the peripheral portion We cannot be completely removed by the rough grinding unit 510 described above, the peripheral portion We is completely removed by the medium grinding unit 520. That is, the peripheral portion We may be removed in two stages, the rough grinding unit 510 and the medium grinding unit 520. In this case, the size of the peripheral portion We to be removed can be reduced in stages. That is, the peripheral portion We to be removed by each of the grinding units 510 and 520 becomes smaller.

[0199] Next, the chuck 461 is moved to the third processing position A3. Then, the finish grinding unit 530 finish-grinds the processing surface Wg of the processing target wafer W.

[0200] Next, the chuck 461 is moved to the delivery position A0. Here, the processing surface Wg of the processing target wafer W is roughly cleaned with a cleaning liquid using a cleaning liquid nozzle (not shown). At this time, cleaning is performed to remove dirt from the processing surface Wg to a certain extent.

[0201] Next, the overlapped wafer T is transferred by the transfer unit 470 from the delivery position A0 to the second cleaning unit 500. Then, in the second cleaning unit 500, with the target wafer W held on the transfer pad 472, the non-bonding surface Sn of the supporting wafer S is cleaned and dried.

[0202] Next, the overlapped wafer T is transferred by the transfer unit 470 from the second cleaning unit 500 to the first cleaning unit 490. Then, in the first cleaning unit 490, the processing surface Wg of the processing target wafer W is finish-cleaned with a cleaning liquid using a cleaning liquid nozzle (not shown). At this time, the processing surface Wg is cleaned and dried to a desired degree of cleanliness.

[0203] Next, the overlapped wafer T is transferred by the wafer transfer device 432 to wet etching devices 440 and 441 in this order, and the processing surface Wg is wet etched in two stages.

[0204] Thereafter, the laminated wafer T which has been subjected to all the processes is transferred by the wafer transfer device 432 to the transition device 434, and further transferred by the wafer transfer device 422 to the cassette Ct on the cassette mounting table 10. In this manner, a series of wafer processes in the substrate processing system 400 is completed.

[0205] In the above third embodiment as well, it is possible to enjoy the same effects as in the above first and second embodiments.

[0206] The substrate processing system 400 of this embodiment may further include an edge removing apparatus 210. The edge removing apparatus 210 is provided, for example, stacked on the processing unit 480 and the first cleaning unit 490.

[0207] In this case, after the modified layer M and the modified surface R4 or R5 are formed in the processing unit 480, the peripheral portion We is removed from the modified layer M in the peripheral removal device 210. Then, rough grinding in the rough grinding unit 510, medium grinding in the medium grinding unit 520, finish grinding in the finish grinding unit 530, cleaning of the non-bonding surface Sn in the second cleaning unit 500, cleaning of the processing surface Wg in the first cleaning unit 490, and wet etching of the processing surface Wg in the wet etching devices 440 and 441 are sequentially performed.

[0208] In this embodiment, the laser head 103 for forming the modified layer M and the laser head 321 for forming the modified surface R4 or R5 are provided in the processing unit 480 that aligns the overlapped wafer T, but the device configuration is not limited to this. The modified layer forming unit that includes the laser head 103, the moving mechanism 104, and the lifting mechanism 105 and forms the modified layer M, and the interface processing unit that includes the laser head 321, the moving mechanism 322, and the lifting mechanism 323 and forms the modified surface R4 or R5 may be provided separately from the processing unit 480. The modified layer forming unit and the interface processing unit can be disposed at any position within a range in which the transport unit 470 can transport the overlapped wafer T. For example, the modified layer forming unit and the interface processing unit may be stacked on the processing unit 480. Alternatively, they may be provided at a position adjacent to the processing unit 480 in the horizontal direction, for example, at a position opposite the processing unit 480 across the moving mechanism 473. Either the modified layer forming unit or the interface treatment unit may be disposed inside the processing apparatus 450. Alternatively, both the modified layer forming unit and the interface treatment unit may be disposed outside the processing apparatus 50.

[0209] The substrate processing system 400 of this embodiment may also be provided with a CMP (Chemical Mechanical Polishing) apparatus for polishing the processing surface Wg of the processing target wafer W, and in such a case, a cleaning apparatus for cleaning the processing surface Wg after polishing may also be provided. The CMP apparatus may be provided, for example, in the processing station 402, on the negative Y-axis side of the wafer transfer region 430. The cleaning apparatus may also be provided stacked on the wet etching apparatuses 440, 441, for example, on the positive X-axis side of the wafer transfer region 430.

[0210] In the substrate processing system 400 of the present embodiment, the bonding of the target wafer W and the support wafer S is performed by a bonding device external to the substrate processing system 400, but such a bonding device may be provided inside the substrate processing system 400. In such a case, cassettes Cw, Cs, and Ct capable of accommodating a plurality of target wafers W, a plurality of support wafers S, and a plurality of overlapped wafers T, respectively, are carried in and out of the carry-in / out station 401 of the substrate processing system 400. These cassettes Cw, Cs, and Ct can be freely placed in a row in the Y-axis direction on the cassette mounting table 410.

[0211] In the above embodiment, the case where the processing target wafer W and the support wafer S are directly bonded to each other has been described, but the processing target wafer W and the support wafer S may be bonded to each other via an adhesive.

[0212] Although the embodiment of the present invention has been described above, the present invention is not limited to such examples. It is clear that a person skilled in the art can come up with various modified or revised examples within the scope of the technical ideas described in the claims, and it is understood that these also naturally belong to the technical scope of the present invention. [Explanation of symbols]

[0213] 1. Substrate Processing System 2 Loading / unloading station 3 Processing Station 22 Wafer transport device 30 Bonding equipment 31 Modified layer forming device 32 Processing equipment 40 Control device 100 Chuck 101 Moving mechanism 102 Rotation mechanism 103 Laser Head 104 Moving mechanism 105 Lifting mechanism 200 Substrate Processing System 210 Edge removal device 300, 310 Interface treatment device 320, 330 Processing device 400 Substrate Processing System 401 Loading / unloading station 402 Processing Station 450 Processing equipment 480 Processing Units 510 Rough Grinding Unit 520 Medium grinding unit 530 Finish Grinding Unit C Crack D Device Layer Fw, Fs oxide film M Modification layer M' Radial modified layer M” Split modified layer R1, R2 modified groove R3, R4, R5 modified surface S Support Wafer T Polymer Wafer W (W1, W2) Wafer to be processed Wc central part We Periphery

Claims

1. A substrate processing apparatus for processing a laminated substrate in which a first substrate and a second substrate are bonded together, comprising: a modified layer formed inside the first substrate along a boundary between a peripheral portion and a central portion of the first substrate to be removed by irradiating the first substrate with a laser beam from a processing surface side of the first substrate; a second modified layer formed radially outward from the boundary inside the first substrate for dividing the peripheral portion into small pieces when removing the peripheral portion; and a chuck that holds the laminated substrate in a state in which the first substrate is disposed on an upper side and the second substrate is disposed on a lower side. A drive unit that moves a grinding wheel provided above the chuck in a vertical direction, The first substrate and the grinding wheel are brought into contact with each other, The substrate processing apparatus removes the peripheral portion based on the modified layer and the another modified layer.

2. With the first substrate and the grinding wheel in contact with each other, 2. The substrate processing apparatus according to claim 1, wherein the processing surface of the first substrate is ground by lowering the grinding wheel, and a crack is caused to develop from the modified layer to remove the peripheral portion.

3. The drive unit is configured to be able to rotate the grinding wheel, The chuck is configured to be able to rotate the laminated substrate, With the first substrate and the grinding wheel in contact with each other, 3. The substrate processing apparatus according to claim 2, wherein the grinding wheel is lowered while rotating the chuck and the grinding wheel, thereby grinding the processed surface and removing the peripheral portion.

4. In a state where the first substrate and a part of the arc of the grinding wheel are in contact with each other, The substrate processing apparatus according to claim 3 , wherein a rotation direction of the grinding wheel relative to the rotating first substrate is changed from an outer side to an inner side of the first substrate.

5. In a state where the first substrate and a part of the arc of the grinding wheel are in contact with each other, The substrate processing apparatus according to claim 3 , wherein a rotation direction of the grinding wheel relative to the rotating first substrate is changed from an inner side to an outer side of the first substrate.

6. at least, a rough grinding unit configured to roughly grind the first substrate; a finish grinding unit that finish-grinds the first substrate, The substrate processing apparatus according to any one of claims 3 to 5, wherein the peripheral portion is removed before the finish grinding.

7. The substrate processing apparatus according to any one of claims 1 to 6, wherein the modified layer is formed so that cracks extending from the modified layer do not reach a surface of the first substrate opposite to a bonding surface between the first substrate and the second substrate.

8. The substrate processing apparatus according to any one of claims 1 to 6, wherein the modified layer is formed so that cracks extending from the modified layer reach a surface of the first substrate opposite to a bonding surface between the first substrate and the second substrate.

9. 9. The substrate processing apparatus according to claim 1, wherein a bonding strength reduced portion is formed at an interface between the first substrate and the second substrate in the peripheral portion.

10. A substrate processing method for processing a laminated substrate in which a first substrate and a second substrate are bonded together, comprising the steps of: a modified layer formed inside the first substrate along a boundary between a peripheral portion and a central portion of the first substrate to be removed by irradiating the first substrate with a laser beam from a processing surface side of the first substrate; holding the laminated substrate including another modified layer formed radially outward from the boundary within the first substrate for breaking the peripheral portion into small pieces when removing the peripheral portion, on a chuck with the first substrate disposed on the upper side and the second substrate disposed on the lower side; abutting the first substrate against a grinding wheel provided above the chuck, and removing the peripheral portion based on the modified layer and the other modified layer.

11. With the first substrate and the grinding wheel in contact with each other, The substrate processing method according to claim 10 , further comprising the step of lowering the grinding wheel to grind the processing surface of the first substrate and remove the peripheral portion.

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