Substrate Processing Method and Substrate Processing Apparatus

Abstract

To form a peripheral modification layer in an appropriate position in a polymerized substrate where substrates are bonded together.SOLUTION: A substrate processing method for processing a substrate has a step for holding a second substrate in a polymerized substrate in which the first and second substrates are bonded, and a step for irradiating the boundary between the periphery and the center of a removal target inside the first substrate with a laser beam for the periphery to form a periphery modification layer, and the polymerized substrate has a bonded area where the surface of the first substrate and the surface of the second substrate are bonded and an unbonded area that is the area radially outside the outer edge of the bonded area, and in forming the peripheral modification layer, the laser beam for the periphery is irradiated so that the distance between the peripheral modification layer and the outer edge of the bonded area is within 500 μm.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present disclosure relates to a substrate processing method and a substrate processing apparatus.

Background Art

[0002] Patent Document 1 discloses a method for manufacturing a stacked semiconductor device. In this manufacturing method, two or more semiconductor wafers are stacked to manufacture a stacked semiconductor device. At this time, after each semiconductor wafer is stacked on another semiconductor wafer, the back surface is ground so as to have a desired thickness.

[0003] Patent Document 2 discloses rotating a disk-shaped grinding tool provided with abrasive grains on its outer peripheral portion, and linearly contacting at least the outer peripheral surface of the grinding tool with a semiconductor wafer to grind the peripheral end portion of the semiconductor wafer into a substantially L shape. The semiconductor wafer is manufactured by bonding two silicon wafers together.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] The technology according to the present disclosure forms a peripheral modification layer at an appropriate position in a polymerized substrate in which substrates are joined together.

Means for Solving the Problems

[0006] One aspect of the present disclosure is a substrate processing method for processing a substrate, comprising holding the second substrate in a polymerized substrate in which a first substrate and a second substrate are joined, and irradiating a peripheral laser beam inside the first substrate along the boundary between a peripheral portion and a central portion to be removed to form a peripheral modified layer. The polymerized substrate has a joined region where the surface of the first substrate and the surface of the second substrate are joined, and an unjoined region which is a region radially outside the outer end of the joined region. When forming the peripheral modified layer, radially inward of the outer end of the joining region, the peripheral laser beam is irradiated so that the distance between the peripheral modified layer and the outer end of the joined region is within 500 μm.

Advantages of the Invention

[0007] According to the present disclosure, in a polymerized substrate in which substrates are joined, a peripheral modified layer can be formed at an appropriate position.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Figure 16

Figure 17

Figure 18

Figure 19

Figure 20

Figure 21

Figure 22

Figure 23

Figure 24

Figure 25

Figure 26

Figure 27

Figure 28

Figure 29

Figure 30

Figure 31

Figure 32

Figure 33

Figure 34

Figure 35

Embodiments for Carrying Out the Invention

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

[0010] The grinding process of the back surface of the wafer is performed, for example, by rotating the wafer and the grinding wheel while bringing the grinding wheel into contact with the back surface, and further lowering the grinding wheel. In such a case, the grinding wheel wears out and needs to be replaced regularly. Also, in the grinding process, grinding water is used and its waste liquid treatment is also required. For this reason, the conventional wafer thinning process incurs running costs.

[0011] Also, usually, the peripheral portion of the wafer is chamfered. However, when the back surface of the wafer is ground as described above, the peripheral portion of the wafer becomes a sharp and pointed shape (so-called knife edge shape). Then, chipping occurs at the peripheral portion of the wafer, and the wafer may be damaged. Therefore, so-called edge trim is performed to remove the peripheral portion of the wafer in advance before the grinding process.

[0012] The end face grinding device described in Patent Document 2 above is a device that performs this edge trim. However, in this end face grinding device, since the edge trim is performed by grinding, the grinding wheel wears out and needs to be replaced regularly. Also, a large amount of grinding water is used, and waste liquid treatment is required. Therefore, the conventional edge trim incurs running costs.

[0013] The technology according to the present disclosure efficiently performs these pretreatment processes in order to efficiently perform the thinning process and edge trim of the wafer. Hereinafter, a wafer processing system as a substrate processing device according to the present embodiment and a wafer processing method as a substrate processing method will be described with reference to the drawings. In this specification and the drawings, elements having substantially the same functional configuration are denoted by the same reference numerals, and redundant description is omitted.

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

[0015] In the wafer processing system 1, as shown in FIGS. 2 and 3, a predetermined process is performed on a polymerized wafer T as a polymerized substrate in which a processing wafer W as a first substrate and a support wafer S as a second substrate are joined. Then, in the wafer processing system 1, the peripheral portion We of the processing wafer W is removed, and the processing wafer W is further thinned. Hereinafter, in the processing wafer W, the surface joined to the support wafer S is referred to as the front surface Wa, and the surface on the side opposite to the front surface Wa is referred to as the back surface Wb. Similarly, in the support wafer S, the surface joined to the processing wafer W is referred to as the front surface Sa, and the surface on the side opposite to the front surface Sa is referred to as the back surface Sb.

[0016] The processed wafer W is a semiconductor wafer such as a silicon wafer, and a device layer (not shown) including a plurality of devices is formed on the surface Wa. Further, an oxide film F, for example, SiO 2 film (TEOS film) is formed. The peripheral edge We of the processed wafer W is chamfered, and the cross section of the peripheral edge We becomes thinner toward the tip. Further, the peripheral edge We is a portion to be removed in edge trimming, for example, in the range of 1 mm to 5 mm in the radial direction from the outer end of the processed wafer W.

[0017] In FIG. 2, for the sake of avoiding complication of illustration, the illustration of the oxide film F is omitted. Similarly, in other drawings used in the following description, the illustration of the oxide film F may be omitted.

[0018] The support wafer S is a wafer that supports the processed wafer W, for example, a silicon wafer. An oxide film (not shown) is formed on the surface Sa of the support wafer S. Further, the support wafer S functions as a protective material for protecting the devices on the surface Wa of the processed wafer W. When a plurality of devices are formed on the surface Sa of the support wafer S, a device layer (not shown) is formed on the surface Sa in the same manner as the processed wafer W.

[0019] Here, if the processed wafer W and the support wafer S are joined at the peripheral edge We of the processed wafer W, there is a risk that the peripheral edge We cannot be appropriately removed. Therefore, at the interface between the processed wafer W and the support wafer S, a joined region Aa where the oxide film F and the surface Sa of the support wafer S are joined and an unjoined region Ab which is a region radially outside the joined region Aa are formed. The existence of the unjoined region Ab in this way enables the peripheral edge We to be appropriately removed. Although details will be described later, it is preferable that the outer end of the joined region Aa is positioned slightly radially outside the inner end of the peripheral edge We to be removed.

[0020] As shown in FIG. 1, the wafer processing system 1 has a configuration in which a loading / unloading station 2 and a processing station 3 are integrally connected. The loading / unloading station 2 receives and delivers, for example, a cassette Ct capable of accommodating a plurality of polymerized wafers T to and from the outside. The processing station 3 is provided with various processing apparatuses for performing predetermined processing on the polymerized wafers T.

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

[0022] On the negative X-axis side of the cassette mounting table 10 in the loading / unloading station 2, a wafer transfer device 20 is provided adjacent to the cassette mounting table 10. The wafer transfer device 20 is configured to be movable on a transfer path 21 extending in the Y-axis direction. The wafer transfer device 20 has, for example, two transfer arms 22, 22 for holding and transferring the polymerized wafers T. Each transfer arm 22 is configured to be movable in the horizontal direction, the vertical direction, around the horizontal axis, and around the vertical axis. Note that the configuration of the transfer arm 22 is not limited to the present embodiment and can take any configuration. The wafer transfer device 20 is configured to be able to transfer the polymerized wafers T to the cassette Ct on the cassette mounting table 10 and a transition device 30 described later.

[0023] On the negative X-axis side of the wafer transfer device 20 in the loading / unloading station 2, a transition device 30 for delivering the polymerized wafers T is provided adjacent to the wafer transfer device 20.

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

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

[0026] The etching apparatus 40 etches the back surface Wb of the processed wafer W ground by a processing apparatus 80 described later. For example, a chemical solution (etching solution) is supplied to the back surface Wb, and the back surface Wb is wet-etched. Examples of the chemical solution include HF, HNO 3 , H 3 PO 4 , TMAH, Choline, KOH, etc. are used.

[0027] The cleaning apparatus 41 cleans the back surface Wb of the processed wafer W ground by a processing apparatus 80 described later. For example, a brush is brought into contact with the back surface Wb, and the back surface Wb is scrubbed and cleaned. Note that for cleaning the back surface Wb, a pressurized cleaning liquid may be used. Further, the cleaning apparatus 41 may be configured to clean the back surface Sb of the support wafer S together with the back surface Wb of the processed wafer W.

[0028] The wafer transfer apparatus 50 is arranged, for example, on the negative Y-axis side with respect to the etching apparatus 40 and the cleaning apparatus 41. The wafer transfer apparatus 50 has, for example, two transfer arms 51, 51 that hold and transfer the polymerized wafer T. Each transfer arm 51 is configured to be movable in the horizontal direction, the vertical direction, around the horizontal axis, and around the vertical axis. Note that the configuration of the transfer arm 51 is not limited to this embodiment and can take any configuration. And the wafer transfer apparatus 50 is configured to be able to transfer the polymerized wafer T to the transition apparatus 30, the etching apparatus 40, the cleaning apparatus 41, and a modification apparatus 60 described later.

[0029] The second processing block G2 is provided with a reforming device 60, a peripheral removal device 61, and a wafer transfer device 70. The reforming device 60 and the peripheral removal device 61 are arranged in a stacked manner. Note that the number and arrangement of the reforming device 60 and the peripheral removal device 61 are not limited to this.

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

[0031] The peripheral removal device 61 removes the peripheral portion We of the processing wafer W based on the peripheral reforming layer formed by the reforming device 60. The specific configuration of the peripheral removal device 61 will be described later.

[0032] The wafer transfer device 70 is arranged, for example, on the positive Y-axis side with respect to the reforming device 60 and the peripheral removal device 61. The wafer transfer device 70 has, for example, two transfer arms 71, 71 that hold and transfer the polymerized wafer T. Each transfer arm 71 is supported by an articulated arm member 72 and is configured to be movable in the horizontal direction, vertical direction, around the horizontal axis, and around the vertical axis. The specific configuration of the transfer arm 71 will be described later. Then, the wafer transfer device 70 is configured to be able to transfer the polymerized wafer T to the cleaning device 41, the reforming device 60, the peripheral removal device 61, and a processing device 80 described later.

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

[0034] The processing device 80 grinds the back surface Wb of the processing wafer W. Then, on the back surface Wb where the internal surface modified layer is formed, the internal surface modified layer is removed, and further the peripheral modified layer is removed. Specifically, the processing device 80 rotates the processing wafer W and the grinding wheel (not shown) while bringing the back surface Wb of the processing wafer W held by the chuck 81 into contact with the grinding wheel (not shown), and grinds the back surface Wb. In this embodiment, the chuck 81 and the grinding wheel (not shown) constitute the processing unit. Further, a known grinding device (polishing device) is used for the processing device 80, and for example, the device described in Japanese Patent Application Laid-Open No. 2010-69601 is used.

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

[0036] Next, the above-described modification device 60 will be described. FIG. 4 is a plan view showing an outline of the configuration of the modification device 60. FIG. 5 is a side view showing an outline of the configuration of the modification device 60.

[0037] The modification device 60 has a chuck 100 as a substrate holding unit that holds the polymerized wafer T on its upper surface. The chuck 100 adsorbs and holds the support wafer S in a state where the processing wafer W is on the upper side and the support wafer S is on the lower side. The chuck 100 is supported by a slider table 102 via an air bearing 101. A rotating unit 103 is provided on the lower surface side of the slider table 102. The rotating unit 103 incorporates, for example, a motor as a drive source. The chuck 100 is configured to be rotatable about a vertical axis by the rotating unit 103 via the air bearing 101. The slider table 102 is configured to be movable along a rail 105 provided on a base 106 and extending in the Y-axis direction by a horizontal movement unit 104 provided on the lower surface side thereof. Note that the drive source of the horizontal movement unit 104 is not particularly limited, and for example, a linear motor is used.

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

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

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

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

[0042] Above the chuck 100 and on the positive Y-axis side of the laser head 110, a macro camera 140 and a micro camera 150 are provided. For example, the macro camera 140 and the micro camera 150 are integrally configured, and the macro camera 140 is disposed on the positive Y-axis side of the micro camera 150. The macro camera 140 and the micro camera 150 are configured to be movable up and down by an elevating mechanism 160 and further configured to be movable in the Y-axis direction by a moving mechanism 161.

[0043] The macro camera 140 images the outer edge of the processed wafer W (bonded wafer T). The macro camera 140 includes, for example, a coaxial lens, irradiates visible light, for example, red light, and further receives reflected light from the object. For example, the imaging magnification of the macro camera 140 is 2 times.

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

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

[0046] The peripheral removal device 61 has a chuck 170 as another substrate holding part that holds the polymerized wafer T on its upper surface. The chuck 170 adsorbs and holds the support wafer S in a state where the processing wafer W is on the upper side and the support wafer S is on the lower side. Further, the chuck 170 is configured to be rotatable about a vertical axis by a rotation mechanism 171.

[0047] Above the chuck 170, a pad 180 as a peripheral removal part for holding and transferring the peripheral part We of the processing wafer W is provided. A suction mechanism (not shown) such as a vacuum pump is connected to the pad 180, and the pad 180 adsorbs and holds the peripheral part We on its lower surface. The pad 180 is provided with a lifting mechanism 181 for lifting and lowering the pad 180 in the vertical direction and a moving mechanism 182 for moving the pad 180 in the horizontal direction (X-axis direction and Y-axis direction).

[0048] Above the chuck 170, a detection unit 190 for confirming whether the peripheral part We has been removed from the processing wafer W is provided. The detection unit 190 detects the presence or absence of the peripheral part We in the processing wafer W held by the chuck 170 and from which the peripheral part We has been removed. For example, a sensor is used for the detection unit 190. The sensor is, for example, a line type laser displacement meter, and detects the presence or absence of the peripheral part We by irradiating the laser to the peripheral part of the polymerized wafer T (processing wafer W) and measuring the thickness of the polymerized wafer T. Note that the method for detecting the presence or absence of the peripheral part We by the detection unit 190 is not limited to this. For example, a line camera may be used for the detection unit 190, and the presence or absence of the peripheral part We may be detected by imaging the polymerized wafer T (processing wafer W).

[0049] Note that a recovery unit (not shown) for recovering the peripheral part We transferred by the pad 180 is provided below the chuck 170. The recovery unit accommodates and recovers the peripheral part We adsorbed and held by the pad 180.

[0050] Next, the transfer arm 71 of the wafer transfer device 70 described above will be described. FIG. 8 is a longitudinal sectional view showing an outline of the configuration of the transfer arm 71.

[0051] The transfer arm 71 as the substrate separation part and the transfer part has a disk-shaped suction plate 200 having a diameter larger than that of the polymerization wafer T. A holding part 210 for holding the central part Wc of the processing wafer W is provided on the lower surface of the suction plate 200.

[0052] A suction pipe 211 for sucking the central part Wc is connected to the holding part 210, and the suction pipe 211 communicates with a suction mechanism 212 such as a vacuum pump. A pressure sensor 213 for measuring the suction pressure is provided in the suction pipe 211. The configuration of the pressure sensor 213 is arbitrary, but for example, a diaphragm type pressure gauge is used.

[0053] A rotation mechanism 220 for rotating the suction plate 200 around the vertical axis is provided on the upper surface of the suction plate 200. The rotation mechanism 220 is supported by a support member 221. Further, the support member 221 (rotation mechanism 220) is supported by an arm member 72.

[0054] Next, the wafer processing according to the first embodiment performed using the wafer processing system 1 configured as described above will be described. FIG. 9 is a flowchart showing the main steps of the wafer processing. FIG. 10 is an explanatory diagram of the main steps of the wafer processing. In the present embodiment, the processing wafer W and the support wafer S are joined by a joining device (not shown) outside the wafer processing system 1, and the polymerization wafer T is formed in advance.

[0055] First, a cassette Ct containing a plurality of polymerization wafers T shown in FIG. 10(a) is placed on the cassette mounting table 10 of the loading / unloading station 2.

[0056] Next, the polymerized wafer T in the cassette Ct is taken out by the wafer transfer device 20 and transferred to the transition device 30. Subsequently, the polymerized wafer T of the transition device 30 is taken out by the wafer transfer device 50 and transferred to the modification device 60. In the modification device 60, as shown in FIG. 10(b), the peripheral modification layer M1 and the divided modification layer M2 are sequentially formed inside the processing wafer W (steps A1 and A2 in FIG. 9), and further, as shown in FIG. 10(c), the inner surface modification layer M3 is formed (step A3 in FIG. 9). The peripheral modification layer M1 serves as a reference point when removing the peripheral portion We during edge trimming. The divided modification layer M2 serves as a reference point for fragmenting the removed peripheral portion We into small pieces. The inner surface modification layer M3 serves as a reference point for thinning the processing wafer W.

[0057] FIG. 11 is an explanatory diagram of the main steps of the modification process in the modification device 60. First, as shown in FIG. 11(a), the chuck 100 (slider table 102) is moved to the loading / unloading position P1. Then, the polymerized wafer T is carried in from the wafer transfer device 50 and held by the chuck 100.

[0058] Next, as shown in FIG. 11(b), the chuck 100 is moved to the macro alignment position P2. The macro alignment position P2 is a position where the macro camera 140 can image the outer edge of the processing wafer W.

[0059] Next, an image of the outer edge of the processing wafer W in the circumferential direction of 360 degrees is captured by the macro camera 140. The captured image is output from the macro camera 140 to the control device 90.

[0060] In the control device 90, a first eccentricity between the center Cc of the chuck 100 and the center Cw of the processed wafer W is calculated from the image of the macro camera 140. Further, in the control device 90, based on the first eccentricity, the movement amount of the chuck 100 is calculated so as to correct the Y-axis component of the first eccentricity. The chuck 100 moves in the Y-axis direction based on the calculated movement amount, and moves the chuck 100 to the micro-alignment position P3 as shown in FIG. 11(c). The micro-alignment position P3 is a position where the micro camera 150 can image the peripheral portion of the processed wafer W. Here, as described above, since the field of view of the micro camera 150 is about 1 / 5 smaller than that of the macro camera 140, if the Y-axis component of the first eccentricity is not corrected, the peripheral portion of the processed wafer W may not enter the angular field of the micro camera 150 and may not be imaged by the micro camera 150. Therefore, the correction of the Y-axis component based on the first eccentricity can be said to be for moving the chuck 100 to the micro-alignment position P3.

[0061] Next, the micro camera 150 images the boundary between the bonding region Aa and the non-bonding region Ab in the circumferential direction of 360 degrees of the processed wafer W. The captured image is output from the micro camera 150 to the control device 90.

[0062] In the control device 90, a second eccentricity between the center Cc of the chuck 100 and the center Ca of the bonding region Aa is calculated from the image of the micro camera 150. Further, in the control device 90, based on the second eccentricity, the position of the chuck 100 with respect to the peripheral modification layer M1 is determined so that the center of the bonding region Aa coincides with the center of the chuck 100. Here, as described above, the non-bonding region Ab is formed before bonding the processed wafer W and the support wafer S, and the center of the non-bonding region Ab (the center Ca of the bonding region Aa) may be displaced from the center of the processed wafer W. In this regard, by adjusting the position of the chuck 100 with respect to the peripheral modification layer M1 based on the second eccentricity as in the present embodiment, the displacement of the non-bonding region Ab is corrected.

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

[0064] Next, as shown in FIGS. 12 and 13, laser light L1 (peripheral laser light L1) is irradiated from the laser head 110 to form a peripheral modification layer M1 at the boundary between the peripheral portion We and the central portion Wc of the processing wafer W (step A1 in FIG. 9). The shape and number of the laser light L1 are adjusted by LCOS. Specifically, the focus position and phase of the laser light L1 are controlled so that the peripheral modification layer M1 described later is formed, and the shape is adjusted. In the present embodiment, the number of the laser light L1 is one.

[0065] The peripheral modification layer M1 formed by the laser light L1 extends in the thickness direction and has an aspect ratio with a vertical length. The lower end of the peripheral modification layer M1 is located above the target surface (dotted line in FIG. 12) of the processed wafer W after thinning. That is, the distance H1 between the lower end of the peripheral modification layer M1 and the surface Wa of the processed wafer W is larger than the target thickness H2 of the processed wafer W after thinning. In such a case, the peripheral modification layer M1 does not remain on the processed wafer W after thinning. Note that a crack C1 has propagated from the peripheral modification layer M1 inside the processed wafer W and reached the front surface Wa and the back surface Wb.

[0066] Note that the peripheral modification layer M1 is formed radially inward of the outer end of the bonding region Aa. When the peripheral modification layer M1 is formed by the laser light L1 from the laser head 110, even if the peripheral modification layer M1 is formed deviated from the outer end of the bonding region Aa due to, for example, a processing error, it is possible to suppress the peripheral modification layer M1 from being formed radially outward from the outer end of the bonding region Aa. Here, if the peripheral modification layer M1 is formed radially outward from the outer end of the bonding region Aa, the processed wafer W will float with respect to the support wafer S after the peripheral portion We is removed. In this regard, in the present embodiment, such a state of the processed wafer W can be surely suppressed.

[0067] In addition, as a result of intensive studies by the present inventors, it has been confirmed that when the distance D between the peripheral modified layer M1 and the outer end of the bonding region Aa is sufficiently small, the peripheral portion We can be appropriately removed. And this distance D is preferably within 500 μm, more preferably within 50 μm.

[0068] Here, as described above, in the control device 90, the position of the chuck 100 is determined based on the second eccentricity. In step A1, in accordance with the determined position of the chuck 100, the chuck 100 is rotated by the rotating unit 103 and the chuck 100 is moved in the Y-axis direction by the horizontal moving unit 104 so that the center of the bonding region Aa coincides with the center of the chuck 100. At this time, the rotation of the chuck 100 and the movement in the Y-axis direction are synchronized. By performing such perfect synchronization control, the movement of the chuck 100 can be appropriately followed with little error to the determined position.

[0069] Then, while rotating and moving the chuck 100 (processed wafer W) in this way, the processed wafer W is irradiated with the laser beam L1 from the laser head 110 into the inside. That is, while correcting the second eccentricity, the peripheral modified layer M1 is formed. Then, the peripheral modified layer M1 is formed in an annular shape concentric with the bonding region Aa. That is, the distance D between the peripheral modified layer M1 and the outer end of the bonding region Aa shown in FIG. 12 can be made constant. For this reason, thereafter, in the peripheral removing device 61, the peripheral portion We can be appropriately removed with the peripheral modified layer M1 as a base point.

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

[0071] Next, the laser head 110 is moved in the Y-axis direction, and as shown in FIGS. 14 and 15, laser light L2 (laser light L2 for splitting) is irradiated from the laser head 110 to form a split modification layer M2 on the radially outer side of the peripheral modification layer M1 (step A2 in FIG. 9). At this time, by means of LCOS, the laser light irradiated from the laser head 110 is switched from laser light L1 to laser light L2, and the shape and number of the laser light L2 are adjusted. Specifically, the laser light L2 is adjusted in shape by controlling its focal position and phase so as to form the split modification layer M2 described later. Also, in the present embodiment, the number of the laser light L2 is one.

[0072] The split modification layer M2 also extends in the thickness direction in the same manner as the peripheral modification layer M1 and has a vertically long aspect ratio. In the present embodiment, the split modification layer M2 is formed at the same height as the peripheral modification layer M1. Also, cracks C2 have propagated from the split modification layer M2 and reached the front surface Wa and the back surface Wb.

[0073] Also, by forming a plurality of split modification layers M2 and cracks C2 at a pitch of several μm in the radial direction, as shown in FIG. 15, one line of split modification layer M2 extending radially outward from the peripheral modification layer M1 is formed. In the example shown in the figure, the split modification layer M2 of the line extending in the radial direction is formed at eight locations, but the number of the split modification layer M2 is arbitrary. At least if the split modification layer M2 is formed at two locations, the peripheral portion We can be removed. In such a case, when removing the peripheral portion We in edge trimming, the peripheral portion We is separated based on the annular peripheral modification layer M1 and is divided into a plurality by the split modification layer M2. Then, the removed peripheral portion We is fragmented and can be removed more easily.

[0074] In the present embodiment, when forming the split modification layer M2, the laser head 110 is moved in the Y-axis direction, but the chuck 100 may be moved in the Y-axis direction.

[0075] Next, as shown in FIGS. 16 and 17, laser light L3 (laser light L3 for the inner surface) is irradiated from the laser head 110 to form an inner surface modification layer M3 along the surface direction (step A3 in FIG. 9). At this time, by means of LCOS, the laser light irradiated from the laser head 110 is switched from laser light L2 to laser light L3, and the shape and number of the laser light L3 are adjusted. Specifically, the laser light L3 is adjusted in shape by controlling its focal position and phase so as to form the inner surface modification layer M3 described later. Also, in this embodiment, the number of the laser light L3 is one. The black arrows shown in FIG. 17 indicate the rotation direction of the chuck 100, and the same applies to the following description.

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

[0077] In step A3, while rotating the chuck 100 (processed wafer W), the laser head 110 is moved in the Y-axis direction from the outer peripheral portion to the central portion of the processed wafer W, and the processed wafer W is irradiated with the laser light L3 from the laser head 110. Then, the inner surface modification layer M3 is formed in a spiral shape from the outside to the inside within the plane of the processed wafer W.

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

[0079] Next, as shown in FIG. 11(e), the chuck 100 is moved to the loading / unloading position P1. Then, the polymerized wafer T is unloaded by the wafer transfer device 70.

[0080] As described above, in the reforming apparatus 60, the peripheral reforming layer M1 in step A1 and the inner surface reforming layer M3 in step A3 are performed in this order. Here, if the inner surface reforming layer M3 is formed before the peripheral reforming layer M1, the processing wafer W may expand or warp. For example, when the inner surface reforming layer M3 is formed, cracks C3 are formed in the plane direction of the processing wafer W. Then, stress is applied to the cracks C3, and the processing wafer W expands in the plane direction. Further, if the magnitude of this expansion varies depending on the in-plane position of the processing wafer W, local separation of the processing wafer W may progress. In such a case, the height of the processing wafer W becomes non-uniform in the plane, and warping occurs. When the processing wafer W expands or warps in this way, the peripheral reforming layer M1 cannot be formed at an appropriate position. As a result, the peripheral portion We cannot be appropriately removed, and the quality cannot be ensured. In this regard, in the present embodiment, the peripheral reforming layer M1 and the inner surface reforming layer M3 are formed in this order, and expansion and warping of the processing wafer W can be suppressed.

[0081] Next, the polymerization wafer T is transported to the peripheral removal device 61 by the wafer transport device 70. In the peripheral removal device 61, as shown in FIG. 10(d), the peripheral portion We of the processing wafer W is removed based on the peripheral reforming layer M1 (step A4 in FIG. 9). In step A4, as shown in FIG. 18, the pad 180 is lowered by the elevating mechanism 181 to adsorb and hold the peripheral portion We, and then the pad 180 is further raised. Then, the peripheral portion We held by the pad 180 is separated from the processing wafer W with the peripheral reforming layer M1 as a base point. At this time, with the split reforming layer M2 as a base point, the peripheral portion We is fragmented and separated. The removed peripheral portion We is recovered from the pad 180 to a recovery section (not shown).

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

[0083] In step A5, as shown in Fig. 19(a), while the processing wafer W is sucked and held by the suction plate 200 of the transfer arm 71, the support wafer S is sucked and held by the chuck 81. Then, the suction plate 200 is rotated so that the back wafer Wb1 is trimmed with the inner surface modification layer M3 as the boundary. After that, as shown in Fig. 19(b), with the suction plate 200 sucking and holding the back wafer Wb1, the suction plate 200 is lifted to separate the back wafer Wb1 from the processing wafer W. At this time, by measuring the pressure for sucking the back wafer Wb1 with the pressure sensor 213, the presence or absence of the back wafer Wb1 can be detected, and it can be confirmed whether the back wafer Wb1 has been separated from the processing wafer W. Note that if the back wafer Wb1 can be separated only by lifting the suction plate 200 as shown in Fig. 19(b), the rotation of the suction plate 200 shown in Fig. 19(a) may be omitted. Also, the separated back wafer Wb1 is recovered outside the wafer processing system 1.

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

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

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

[0087] Thereafter, the polymerized wafer T that has undergone all the processes is transported to the transition apparatus 30 by the wafer transfer apparatus 50, and further transported to the cassette Ct of the cassette mounting table 10 by the wafer transfer apparatus 20. Thus, a series of wafer processes in the wafer processing system 1 are completed.

[0088] According to the above embodiment, edge trimming is performed by removing the peripheral portion We with the peripheral modification layer M1 as a reference point, and further, the thinning process of the processed wafer W is performed by separating the back surface wafer Wb1 with the inner surface modification layer M3 as a reference point. And the laser head 110 used for forming these peripheral modification layer M1 and inner surface modification layer M3 is less likely to deteriorate over time and the number of consumables is reduced, so the maintenance frequency can be reduced. In addition, since it is a dry process using a laser, grinding water and wastewater treatment are not required. For this reason, the running cost can be reduced. Therefore, the running cost can be suppressed as compared with the conventional edge trimming by grinding and the thinning process by grinding.

[0089] In this embodiment, the back surface Wb is ground in step A6. This grinding only needs to remove the inner surface modification layer M3 and the peripheral modification layer M1, and the grinding amount is as small as about several tens of μm. On the other hand, when the back surface Wb is ground to thin the processed wafer W as in the prior art, the grinding amount is large, for example, 700 μm or more, and the wear degree of the grinding wheel is large. For this reason, in this embodiment, the maintenance frequency can still be reduced.

[0090] Also, according to the present embodiment, the peripheral modification layer M1 and the inner surface modification layer M3 are formed inside the processing wafer W in this order. As described above, if the inner surface modification layer M3 is formed first, the processing wafer W may expand or warp. However, in the present embodiment, the expansion and warping of the processing wafer W can be suppressed. As a result, the peripheral portion We can be appropriately removed, and the quality can be ensured.

[0091] Also, according to the present embodiment, by adjusting the shapes of the laser beams L1 to L3 using one laser head 110, the peripheral modification layer M1, the dicing modification layer M2, and the inner surface modification layer M3 can be formed. That is, even when the direction in which the modification layer extends and the required processing quality are different, an appropriate shape of the laser beam can be selected using one laser head 110. And since the modification layer of an arbitrary shape can be formed in this way, the degree of freedom in forming the modification layer is improved. In addition, the occupied area (footprint) of the apparatus can be reduced, and space saving can be realized. Furthermore, since the apparatus configuration becomes simple, the apparatus cost can be reduced. In this way, in the present embodiment, the thinning process of the processing wafer W and the pretreatment of the edge trim can be efficiently performed.

[0092] In the above embodiment, the laser beams L1 to L3 of different shapes are irradiated by one laser head 110. However, the laser head 110 is preferably calibrated before the polymerization wafer T to be processed is carried into the modification apparatus 60. More specifically, it is preferable to calibrate the laser head 110 before the polymerization wafer T is held by the chuck 100. In such a case, it is not necessary to calibrate the laser head 110 during the modification process for one processing wafer W, and the time required for switching the laser beams L1 to L3 can be shortened. As a result, the throughput of the wafer processing can be improved.

[0093] In the above-described embodiments, when forming the peripheral modification layer M1, one laser beam L1 was irradiated from the laser head 110 into the interior of the processing wafer W. However, a plurality of laser beams L1 may be irradiated. In such a case, the time required to form the peripheral modification layer M1 can be shortened, and the throughput of wafer processing can be further improved. Similarly, when forming the inner surface modification layer M3, one laser beam L3 was irradiated from the laser head 110 into the interior of the processing wafer W. However, a plurality of laser beams L3 may be irradiated. Also in such a case, the time required to form the inner surface modification layer M3 can be shortened, and the throughput of wafer processing can be further improved.

[0094] In the above-described embodiments, in the peripheral removal device 61, the peripheral portion We was removed using the pad 180, and in the processing device 80, the processing wafer W was separated using the transfer arm 71. However, the removal of these peripheral portions We and the transfer arm 71 may be performed within the same device. For example, as shown in FIG. 20, above the chuck 170 in the peripheral removal device 61, a suction plate 230 as a substrate separation unit is further provided. The suction plate 230 has the same configuration as the suction plate 200 of the transfer arm 71 and has a disc shape with a diameter larger than that of the polymerized wafer T. A suction mechanism (not shown), such as a vacuum pump, is connected to the suction plate 230, and the suction plate 230 sucks and holds the back surface Wb of the processing wafer W on its lower surface. The suction plate 230 is provided with a lifting mechanism 231 for lifting and lowering the suction plate 230 in the vertical direction and a rotation mechanism 232 for rotating the suction plate 230 around the vertical axis.

[0095] In such a case, after removing the peripheral portion We with the pad 180 in step A4, the processing wafer W is separated by the suction plate 230 in step A5. In step A5, the back surface Wb of the processing wafer W is sucked and held by the suction plate 230. Then, the suction plate 230 is rotated so that the back surface wafer Wb1 is cut off at the boundary of the inner surface modification layer M3. Thereafter, with the suction plate 230 sucking and holding the back surface wafer Wb1, the suction plate 230 is lifted to separate the back surface wafer Wb1 from the processing wafer W. Note that if the back surface wafer Wb1 can be separated simply by lifting the suction plate 230, the rotation of the suction plate 230 may be omitted.

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

[0097] Also in this embodiment, the removal of the peripheral portion We of the processing wafer W and the separation of the processing wafer W can be appropriately performed. Moreover, since these can be performed within the same apparatus, the throughput of wafer processing can be improved.

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

[0099] The first measure to prevent the peeling of the peripheral portion We is a method of physically pressing the peripheral portion We. For example, as shown in FIG. 21, a plurality of cylindrical peripheral holding portions 240 that abut against the outer end portion of the processing wafer W may be provided. Alternatively, for example, as shown in FIG. 22, a plurality of rectangular parallelepiped peripheral holding portions 241 that abut against the outer end portion of the processing wafer W may be provided. These peripheral holding portions 240 and 241 are each configured to be movable in the vertical and horizontal directions by a moving mechanism (not shown). And although there is a difference in that the peripheral holding portions 240 and 241 are in point contact or line contact with the processing wafer W, in any case, the peeling of the peripheral portion We can be prevented. Note that the peripheral holding portions 240 and 241 only need to abut against the outer end portion of the processing wafer W when forming the inner surface modification layer M3, and may be retracted from the processing wafer W otherwise.

[0100] The second measure to prevent the peeling of the peripheral portion We is a method of advancing the crack C1 formed in the thickness direction of the processing wafer W from the peripheral modification layer M1 only to the surface Wa. By adjusting the shape of the laser beam L1 irradiated from the laser head 110, as shown in FIG. 23(a), the crack C1 advances only to the surface Wa and does not reach the back surface Wb. Similarly, when forming the divided modification layer M2, the crack C2 also advances only to the surface Wa and does not reach the back surface Wb. In such a case, then, as shown in FIG. 23(b), even if the inner surface modification layer M3 is formed, the peripheral portion We does not peel off from the processing wafer W.

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

[0102] In the first embodiment, the removal of the peripheral portion We and the separation of the processed wafer W were performed separately, but in the second embodiment, these are performed simultaneously. The removal of these peripheral portions We and the separation of the processed wafer W are performed, for example, in the processing apparatus 80 using the transfer arm 71 as a removal and separation unit. Note that the transfer arm 71 of the present embodiment holds the entire processed wafer W, that is, the central portion Wc and the peripheral portion We. Further, since the removal of the peripheral portion We is performed using the transfer arm 71 in this manner, the wafer processing system 1 of the present embodiment may omit the peripheral removal device 61.

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

[0104] Here, the method of forming the peripheral reforming layer M10 in step B1 is the same as that in step A1. However, in the peripheral reforming layer M1 shown in FIG. 10(b), the crack C1 has advanced to the front surface Wa and the back surface Wb, whereas the crack C10 from the peripheral reforming layer M10 advances only to the front surface Wa and does not reach the back surface Wb.

[0105] Also, the method of forming the inner surface reforming layer M30 in step B2 is the same as that in step A3. However, in the inner surface reforming layer M3 shown in FIG. 10(c), the crack C3 has advanced to the outer end of the processed wafer W in the plane direction, whereas the crack C30 from the inner surface reforming layer M30 advances only inside the peripheral reforming layer M10.

[0106] Next, the polymerized wafer T is transferred to the processing apparatus 80 by the wafer transfer apparatus 70. In the processing apparatus 80, first, when the polymerized wafer T is transferred from the transfer arm 71 to the chuck 81, as shown in FIG. 25(d), the back surface Wb side of the processed wafer W (hereinafter referred to as the back wafer Wb2) is separated based on the peripheral reforming layer M10 and the inner surface reforming layer M30 (step B3 in FIG. 24).

[0107] In step B3, as shown in FIG. 26(a), while the processing wafer W is sucked and held by the suction plate 200 of the transfer arm 71, the support wafer S is sucked and held by the chuck 81. Then, the suction plate 200 is rotated so that the back wafer Wb2 is cut off at the boundary between the peripheral modification layer M10 and the inner surface modification layer M30. Thereafter, with the suction plate 200 sucking and holding the back wafer Wb2 as shown in FIG. 26(b), the suction plate 200 is raised to separate the back wafer Wb2 from the processing wafer W. In this way, in step B3, the back wafer Wb2 is separated integrally with the peripheral portion We, that is, the removal of the peripheral portion We and the separation of the processing wafer W are performed simultaneously.

[0108] Subsequently, as shown in FIG. 25(e), the back surface Wb of the processing wafer W is ground (step B4 in FIG. 24), and further, cleaning of the back surface Wb in the cleaning device 41 (step B5 in FIG. 24) and wet etching of the back surface Wb in the etching device 40 (step B6 in FIG. 24) are sequentially performed. Thus, a series of wafer processing in the wafer processing system 1 is completed.

[0109] Also in this embodiment, the peripheral modification layer M10 and the inner surface modification layer M30 are formed in this order inside the processing wafer W, and the same effects as those of the first embodiment can be obtained. Moreover, since the crack from the peripheral modification layer M10 does not reach the back surface Wb, the peripheral portion We does not peel off due to the expansion of the processing wafer W during the formation of the inner surface modification layer M30. In order to more reliably prevent the peeling of the peripheral portion We, the peripheral holding portions 240 and 241 may be provided as shown in FIG. 21 or FIG. 22.

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

[0111] The removal and separation device 300 has a chuck 310 as another substrate holding part that holds the polymerized wafer T on its upper surface. The chuck 310 adsorbs and holds the support wafer S in a state where the processing wafer W is on the upper side and the support wafer S is arranged on the lower side. Further, the chuck 310 is configured to be rotatable about a vertical axis by a rotation mechanism 311.

[0112] Above the chuck 310, a suction plate 320 is provided as a removal and separation part. The suction plate 320 has the same configuration as the suction plate 200 of the transfer arm 71 and has a disc shape with a diameter larger than that of the polymerized wafer T. A suction mechanism (not shown) such as a vacuum pump is connected to the suction plate 320, and the suction plate 320 adsorbs and holds the back surface Wb of the processing wafer W on its lower surface. The suction plate 320 is provided with a lifting mechanism 321 for lifting and lowering the suction plate 320 in the vertical direction and a rotation mechanism 322 for rotating the suction plate 320 about a vertical axis.

[0113] In such a case, the back surface Wb of the processing wafer W is adsorbed and held by the suction plate 320. Then, the suction plate 320 is rotated so that the back surface wafer Wb2 is cut off at the boundary between the peripheral modification layer M10 and the inner surface modification layer M30. After that, with the suction plate 320 holding the back surface wafer Wb2 adsorbed, the suction plate 320 is lifted to separate the back surface wafer Wb2 from the processing wafer W. Also in the removal and separation device 300 of the present embodiment, the removal of the peripheral portion We of the processing wafer W and the separation of the processing wafer W can be appropriately performed.

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

[0115] In the first embodiment, the peripheral portion We was removed after forming the inner surface modification layer M3. However, in the third embodiment, the inner surface modification layer M31 is formed after removing the peripheral portion We. That is, in the third embodiment, the formation of the peripheral modification layer M11, the removal of the peripheral portion We, and the formation of the inner surface modification layer M31 are performed in this order. Although the peripheral modification layer M11 and the inner surface modification layer M31 are each performed by the modification device 60, if the removal of the peripheral portion We is performed outside the modification device 60, the throughput decreases. Therefore, in the present embodiment, the removal of the peripheral portion We is performed inside the modification device 60 using the transfer arm 71 as a peripheral removal unit. Since the removal of the peripheral portion We is thus performed using the transfer arm 71, the wafer processing system 1 of the present embodiment may omit the peripheral removal device 61. Note that the transfer arm 71 also functions as a substrate separation unit as will be described later.

[0116] As shown in FIG. 30, the transfer arm 71 has a disk-shaped suction plate 400 having a diameter larger than that of the processing wafer W. On the lower surface of the suction plate 400, a central holding portion 410 for holding the central portion Wc of the processing wafer W and a peripheral holding portion 420 for holding the peripheral portion We of the processing wafer W are provided.

[0117] A suction pipe 411 for sucking the central portion Wc is connected to the central holding portion 410, and the suction pipe 411 communicates with a central suction mechanism 412 such as a vacuum pump, for example. A central pressure sensor 413 for measuring the suction pressure is provided in the suction pipe 411. The configuration of the central pressure sensor 413 is arbitrary, but for example, a diaphragm type pressure gauge is used.

[0118] A suction pipe 421 for sucking the peripheral portion We is connected to the peripheral holding portion 420, and the suction pipe 421 communicates with a peripheral suction mechanism 422 such as a vacuum pump, for example. A peripheral pressure sensor 423 for measuring the suction pressure is provided in the suction pipe 421. The configuration of the peripheral pressure sensor 423 is also arbitrary, but for example, a diaphragm type pressure gauge is used.

[0119] Note that, as shown in FIG. 31, a recessed portion 400a that is recessed upward from the central holding portion 410 is formed in a portion of the peripheral edge of the suction plate 400 where the peripheral edge holding portion 420 is provided. As will be described later, the peripheral edge portion We is pushed up and removed by the peripheral edge removing portion 440, and the recessed portion 400a secures a space for the peripheral edge portion We to be pushed up.

[0120] With such a configuration, the central holding portion 410 and the peripheral edge holding portion 420 can individually suck and hold the central portion Wc and the peripheral edge portion We. Further, the central pressure sensor 413 and the peripheral edge pressure sensor 423 can individually measure the pressure for sucking the central portion Wc and the pressure for sucking the peripheral edge portion We.

[0121] A rotation mechanism 430 for rotating the suction plate 400 about a vertical axis is provided on the upper surface of the suction plate 400. The rotation mechanism 430 is supported by a support member 431. Further, the support member 431 (rotation mechanism 430) is supported by the arm member 72.

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

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

[0124] The support roller 442 penetrates the center of the wedge roller 441 and supports the wedge roller 441. The support roller 442 is configured to be movable horizontally by a moving mechanism (not shown), and when the support roller 442 moves, the wedge roller 441 also moves. Further, the support roller 442 is configured to be rotatable about a vertical axis, and when the support roller 442 rotates, the wedge roller 441 also rotates. In the present embodiment, a so-called free roller that rotates by receiving the rotation of the chuck 100 as described later is used for the support roller 442. However, the support roller 442 may be positively rotated by a rotation mechanism (not shown).

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

[0126] In the wafer processing according to the third embodiment, first, the polymerized wafer T shown in FIG. 29(a) is conveyed to the reforming device 60. In the reforming device 60, as shown in FIG. 29(b), a peripheral reforming layer M11 and a dividing reforming layer M21 are sequentially formed on the processing wafer W (steps C1 and C2 in FIG. 28). The method of forming the peripheral reforming layer M11 in step C1 is the same as that in step A1, and the method of forming the dividing reforming layer M21 in step C2 is the same as that in step A2.

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

[0128] In step C3, first, the back surface Wb of the processing wafer W is sucked and held by the suction plate 400 of the transfer arm 71. Then, as shown in Fig. 32(a), the wedge roller 441 is moved toward the polymerization wafer T side, and the wedge roller 441 is brought into contact with the interface between the processing wafer W and the support wafer S. At this time, by rotating the suction plate 400, the wedge roller 441 also rotates in the reverse direction in plan view. Next, as shown in Fig. 32(b), while rotating the suction plate 400, the wedge roller 441 is further moved and inserted into the interface between the processing wafer W and the support wafer S. Then, the peripheral edge portion We is pushed up, separated from the processing wafer W, and sucked and held by the peripheral edge holding portion 420.

[0129] Thereafter, while the peripheral edge holding portion 420 sucks and holds the peripheral edge portion We, the transfer arm 71 exits from the modification device 60 in a state where the peripheral edge portion We is held by the plurality of wedge rollers 441. Then, in a recovery portion (not shown) provided outside the modification device 60, the peripheral edge portion We is recovered.

[0130] When removing this peripheral edge portion We, the central pressure sensor 413 and the peripheral edge pressure sensor 423 measure the pressure for sucking the central portion Wc and the pressure for sucking the peripheral edge portion We, respectively. When the peripheral edge portion We is properly removed, the pressure for sucking the central portion Wc is zero, and the pressure for sucking the peripheral edge portion We is a predetermined pressure. On the other hand, when the peripheral edge portion We is not properly removed, for example, the pressure for sucking the peripheral edge portion We becomes zero. By measuring the suction pressure with the central pressure sensor 413 and the peripheral edge pressure sensor 423 in this way, it is possible to detect the presence or absence of the peripheral edge portion We with respect to the processing wafer W and confirm whether the peripheral edge portion We has been removed from the processing wafer W.

[0131] Next, in the modification device 60, an inner surface modification layer M31 is formed as shown in Fig. 29(d) (step C4 in Fig. 28). The method for forming the inner surface modification layer M31 in step C4 is the same as that in step A3.

[0132] Next, the polymerized wafer T is transported to the processing apparatus 80 by the wafer transfer apparatus 70. In the processing apparatus 80, first, when transferring the polymerized wafer T from the transfer arm 71 to the chuck 81, as shown in FIG. 29(e), the back surface Wb side of the processing wafer W (hereinafter referred to as the back wafer Wb3) is separated with the inner surface modification layer M31 as a base point (step C5 in FIG. 28). Note that the separation method of the processing wafer W in step C5 is the same as that in step A5. Further, the separation of the processing wafer W is not limited to the method using the transfer arm 71, and for example, a device similar to the peripheral removal device 61 shown in FIG. 20 may be used.

[0133] Subsequently, as shown in FIG. 29(f), the back surface Wb of the processing wafer W is ground (step C6 in FIG. 28), and further, cleaning of the back surface Wb in the cleaning apparatus 41 (step C7 in FIG. 28) and wet etching of the back surface Wb in the etching apparatus 40 (step C8 in FIG. 28) are sequentially performed. Thus, a series of wafer processing in the wafer processing system 1 is completed.

[0134] Also in this embodiment, the peripheral modification layer M11 and the inner surface modification layer M31 are formed in this order inside the processing wafer W, and the same effects as those of the first embodiment can be obtained. Moreover, since the formation of the peripheral modification layer M11 in step C1, the removal of the peripheral portion We in step C3, and the formation of the inner surface modification layer M31 in step C4 are performed in one modification apparatus 60, the throughput of wafer processing can be maintained. In this embodiment, the removal of the peripheral portion We in step C3 is performed inside the modification apparatus 60, but of course, it may be performed by a separate apparatus.

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

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

[0137] The support configuration of the second laser head 500 is also the same as that of the first laser head 110. That is, the second laser head 500 is supported by a support member 510, a rail 511, a lifting mechanism 520, and a moving mechanism 521. And the second laser head 500 is configured to be movable up and down and movable in the Y-axis direction.

[0138] In such a case, for example, when forming the peripheral modification layer M1 in the first embodiment, as shown in FIG. 34, the first laser head 110 and the second laser head 500 are arranged concentrically on the outer periphery of the processing wafer W. Then, while rotating the processing wafer W, laser light L12 is irradiated from the first laser head 110 and laser light L13 is irradiated from the second laser head 500. As a result, the peripheral modification layer M12 is formed by the laser light L12, and the peripheral modification layer M13 is formed by the laser light L13. The peripheral modification layers M12 and M13 are each formed for half a circumference of the processing wafer W, and the peripheral modification layer M1 is formed in an annular shape by combining these peripheral modification layers M12 and M13. That is, in the present embodiment, when forming the peripheral modification layer M1, the processing wafer W only needs to be rotated by 180 degrees. Therefore, the time required to form the peripheral modification layer M1 can be shortened, and as a result, the throughput of wafer processing can be further improved.

[0139] In the above example, the laser light L12 from the first laser head 110 and the laser light L13 from the second laser head 500 are irradiated at the same depth inside the processing wafer W to form the peripheral modification layer M12 and the peripheral modification layer M13 at the same depth. In this regard, the laser light L12 and the laser light L13 may be irradiated at different depths to form the peripheral modification layer M12 and the peripheral modification layer M13 at different depths.

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

[0141] In the above embodiment, the divided modification layer M2 is formed using the laser head 110 that is used for forming the other peripheral modification layer M1 and the internal surface modification layer M3 in the modification apparatus 60, but a separate laser head (not shown) may be used. Further, in the modification apparatus 60, the peripheral modification layer M1, the divided modification layer M2, and the internal surface modification layer M3 may each be formed using a separate laser head (not shown).

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

[0143] The embodiments disclosed herein should be considered illustrative in all respects and not restrictive. The above embodiments may be omitted, replaced, or changed in various forms without departing from the scope and gist of the appended claims.

Explanation of Reference Numerals

[0144] 1 Wafer processing system 60 Modifying device 100 Chuck 110 Laser head S Support wafer T Polymerized wafer W Processed wafer

Claims

1. A substrate processing method for processing a substrate, comprising the steps of: Holding the second substrate in a laminated substrate in which the first substrate and the second substrate are bonded together; irradiating the inside of the first substrate with a peripheral laser light along a boundary between a peripheral portion and a central portion to be removed, thereby forming a peripheral modified layer; The laminated substrate has a bonding region where a surface of the first substrate and a surface of the second substrate are bonded to each other, and an unbonded region which is a region radially outward from an outer end of the bonding region, A substrate processing method in which, in forming the peripheral modification layer, the peripheral laser light is irradiated radially inward from the outer end of the bonding region so that the distance between the peripheral modification layer and the outer end of the bonding region is within 500 μm.

2. 2. The substrate processing method of claim 1, wherein in forming the peripheral modification layer, the peripheral laser light is irradiated radially inward from the outer end of the bonding region so that the distance between the peripheral modification layer and the outer end of the bonding region is within 50 μm.

3. The substrate processing method according to claim 1 , further comprising: acquiring an image by using an imaging section to image a boundary between the bonded region and the unbonded region of the laminated substrate.

4. The substrate processing method according to claim 3 , further comprising correcting, from the image, a deviation between a position where the peripheral modified layer is formed and the outer end of the bonding region.

5. holding the second substrate on the laminated substrate by a substrate holding part configured to be rotatable around an axis perpendicular to the laminated substrate; calculating an amount of eccentricity between a rotation center of the substrate holder and a center of the bonding area from the image; The substrate processing method according to claim 4 , further comprising: correcting the misalignment by adjusting a relative position between a position where the peripheral modified layer is formed and the outer end of the bonding region based on the amount of eccentricity.

6. The substrate processing method according to claim 5 , wherein the substrate holding unit has a movement mechanism, and the relative position between the position where the peripheral modified layer is formed and the outer end of the bonding region is adjusted by the movement mechanism.

7. The imaging unit includes a micro camera that captures an image of a boundary between the bonded region and the unbonded region in the laminated substrate to obtain the image, and a macro camera that captures an image of an outer edge of the laminated substrate; capturing an image of the outer edge of the laminated substrate with the macro camera to obtain a second image; calculating a second eccentricity amount between a center of the substrate holding part and a center of the laminated substrate from the second image; The substrate processing method according to claim 6 , further comprising: determining a position at which the micro camera can capture an image of the boundary between the bonded region and the unbonded region of the laminated substrate based on the second amount of eccentricity.

8. A substrate processing apparatus for processing a substrate, a substrate holder that holds the second substrate in a laminated substrate formed by bonding a first substrate and a second substrate; a modification device that irradiates a peripheral laser beam along a boundary between a peripheral portion and a central portion to be removed inside the first substrate of the laminated substrate held by the substrate holding part to form a peripheral modified layer; The laminated substrate has a bonding region where a surface of the first substrate and a surface of the second substrate are bonded to each other, and an unbonded region which is a region radially outside the bonding region, The modification device is configured to irradiate the peripheral laser light radially inward from the outer end of the bonding region so that the distance between the peripheral modification layer and the outer end of the bonding region is within 500 μm.

9. The substrate processing apparatus of claim 8, wherein the modification device is configured to irradiate the peripheral laser light radially inward from the outer end of the bonding region so that a distance between the peripheral modification layer and the outer end of the bonding region is within 50 μm.

10. The substrate processing apparatus according to claim 8 , further comprising an imaging unit configured to be able to obtain an image by imaging a boundary between the bonded region and the unbonded region in the laminated substrate.

11. The substrate processing apparatus according to claim 10 , further comprising a control unit that executes control including correcting, from the image, a deviation between a position where the peripheral modified layer is formed and the outer end of the bonding region.

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

13. The substrate holder has a moving mechanism, The control unit is The substrate processing apparatus according to claim 12 , further comprising a control unit configured to adjust, by the moving mechanism, the relative position between the position where the peripheral modified layer is formed and the outer end of the bonding region.

14. The imaging unit includes: A micro camera configured to be able to acquire the image by capturing an image of a boundary between the bonded region and the unbonded region in the laminated substrate, and a macro camera capturing an image of an outer edge of the laminated substrate, The control unit is capturing an image of the outer edge of the laminated substrate with the macro camera to obtain a second image; calculating a second eccentricity amount between a center of the substrate holding part and a center of the laminated substrate from the second image; The substrate processing apparatus according to claim 13 , further comprising: determining a position at which the micro camera can capture an image of the boundary between the bonded region and the unbonded region of the laminated substrate based on the second amount of eccentricity.

Images