Substrate processing system and substrate processing method

Abstract

This substrate processing system that processes a substrate comprises: a substrate-holding unit that has a holding surface that holds the substrate; a driving mechanism that moves the substrate-holding unit in a horizontal direction; a rotating mechanism that rotates the substrate-holding unit; a laser irradiation unit that irradiates a laser beam onto the substrate that is being held by the holding surface, and forms a separation surface that constitutes a starting point for separation of the substrate; and a detection mechanism that detects separation starting from the separation surface in the substrate that is being held by the substrate-holding unit.

Description

Substrate processing system and substrate processing method

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

[0002] Patent Document 1 discloses a method for transferring a semiconductor element formed on a surface of a semiconductor substrate having a separation oxide film and a semiconductor element to a destination substrate. The method described in Patent Document 1 includes a step of irradiating the back surface of the semiconductor substrate with light to locally heat the separation oxide film, and a step of causing separation in the separation oxide film and / or at the interface between the separation oxide film and the semiconductor substrate, thereby transferring the semiconductor element to the destination substrate.

[0003] Japan Patent Publication No. 2007-220749

[0004] The technology disclosed herein appropriately detects whether a substrate has been separated after irradiation with laser light and before separation of the substrate, when the substrate is separated using a separation surface formed by irradiation with laser light as a base point.

[0005] One aspect of the present disclosure is a substrate processing system for processing a substrate, comprising: a substrate holding unit having a holding surface for holding the substrate; a drive mechanism for moving the substrate holding unit horizontally; a rotation mechanism for rotating the substrate holding unit; a laser irradiation unit for irradiating the substrate held on the holding surface with laser light to form a separation surface that serves as a base point for separation of the substrate; and a detection mechanism for detecting separation of the substrate held by the substrate holding unit, with the separation surface as the base point.

[0006] According to the present disclosure, when separating a substrate using a separation surface formed by irradiation with laser light as a base point, it is possible to appropriately detect whether the substrate has been separated after irradiation with laser light and before separation of the substrate.

[0007] 1 is a side view showing an outline of the configuration of an overlapped wafer to be processed; FIG. 2 is a plan view showing a schematic outline of the configuration of a wafer processing system; FIG. 3 is a perspective view showing a schematic outline of the configuration of a wafer transport device; FIG. 4 is a side view showing a schematic outline of the configuration of a laser irradiation device; FIG. 5 is a plan view showing a schematic outline of the configuration of a laser irradiation device; FIG. 6 is an explanatory diagram showing eccentricity of a first wafer and a second wafer; FIG. 7 is a side view showing operation of a separation device; FIG. 8 is an explanatory diagram showing irradiation of a laser absorbing layer with laser light; FIG. 9 is a flow diagram showing main steps of wafer processing; FIG. 10 is an explanatory diagram showing an example of irradiation of a laser absorbing layer with laser light; FIG. 11 is an explanatory diagram of an unirradiated region generated in the laser absorbing layer; FIG. 12 is an explanatory diagram showing an example of irradiation of an unirradiated region with laser light; FIG. 13 is an explanatory diagram showing another example of irradiation of an unirradiated region with laser light; FIG. 14 is an explanatory diagram showing the flow of operation of irradiating a laser absorbing layer with laser light; FIG. 15 is an explanatory diagram showing transfer of an overlapped wafer between a chuck and a transport arm; FIG. 16 is an explanatory diagram showing removal of an overlapped wafer from a separation device; FIG. 17 is a side view showing another example of the configuration of a laser irradiation device. 1 is a plan view showing an example of a configuration of a laser irradiation device according to another embodiment; FIG. 2 is a diagram showing an example of an area to be irradiated with laser light set on a laminated wafer; FIG. 3 is a diagram showing an example of a configuration of a laser irradiation device according to another embodiment; FIG. 4 is a diagram showing an example of an operation principle of a spectroscopic interferometer; and FIG. 5 is a diagram showing an example of an inspection of an unbonded surface according to another embodiment.

[0008] In the manufacturing process of semiconductor devices, a device layer formed on the surface of a second semiconductor substrate (hereinafter referred to as "wafer") is transferred to a first wafer in an overlapped wafer formed by bonding two semiconductor substrates (hereinafter referred to as "wafers"). This device layer transfer is performed, for example, using laser lift-off. That is, a laser beam is irradiated into the inside of the overlapped wafer to reduce the bonding strength between the first and second wafers, and then the second wafer is separated from the first wafer, thereby transferring the device layer to the first wafer.

[0009] In some wafer processing systems for performing this laser lift-off, a laser irradiation device that irradiates the overlapping wafer with laser light and a separation device that separates the first wafer and the second wafer are configured independently. Here, after the laser irradiation by the laser irradiation device, the first wafer and the second wafer may be unintentionally separated. In this case, unless horizontal misalignment between the first wafer and the second wafer is detected and suppressed, the second wafer may fall off the first wafer due to inertial forces, etc., associated with the transport operation of the overlapping wafer.

[0010] The technology disclosed herein has been made in consideration of the above circumstances, and when separating substrates using a separation plane formed by irradiation with laser light as a base point, it appropriately detects whether the substrates have been separated after irradiation with laser light but before separation. In the following description, "separation" of the substrate to be detected refers to a state in which a second wafer is moving horizontally relative to a first wafer. More specifically, this includes a state in which the bonding strength of the second wafer to the first wafer is zero and the second wafer can move independently of the first wafer, and a state in which the first wafer and the second wafer are still bonded but the bonding strength has decreased and the second wafer is shifted horizontally relative to the first wafer.

[0011] Hereinafter, a wafer processing system as a substrate processing system and a wafer processing method as a substrate processing method according to the present embodiment will be described with reference to the drawings. Note that in this specification and the drawings, elements having substantially the same functional configurations are designated by the same reference numerals, and redundant description will be omitted.

[0012] In a wafer processing system 1 according to this embodiment, which will be described later, processing is performed on an overlapped wafer T, which is a substrate formed by bonding a first wafer W1 and a second wafer W2 together, as shown in FIG. Hereinafter, the surface of the first wafer W1 that is bonded to the second wafer W2 will be referred to as the front surface W1a, and the surface opposite the front surface W1a will be referred to as the back surface W1b. Similarly, the surface of the second wafer W2 that is bonded to the first wafer W1 will be referred to as the front surface W2a, and the surface opposite the front surface W2a will be referred to as the back surface W2b.

[0013] The first wafer W1 serving as the lower substrate is a semiconductor wafer such as a silicon substrate. In the embodiment, the first wafer W1 has a substantially circular disk shape. A device layer D1 and a surface film F1 are stacked in this order on the surface W1a of the first wafer W1 from the surface W1a side. The device layer D1 includes a plurality of devices. The surface film F1 may be, for example, an oxide film (THOX film, SiO ２ film, TEOS film), SiC film, SiCN film, adhesive, etc.

[0014] The second wafer W2 serving as the upper substrate is also a semiconductor wafer such as a silicon substrate. In the embodiment, the second wafer W2 has a substantially circular disk shape. A laser absorbing layer P, a device layer D2, and a surface film F2 are laminated on the surface W2a of the second wafer W2 in this order from the surface W2a side. The laser absorbing layer P absorbs the laser light irradiated from the laser irradiation unit 110, as will be described later. The laser absorbing layer P may be formed of, for example, an oxide film (SiO ２ A laser absorption layer (film) is used, but is not particularly limited as long as it absorbs laser light. The device layer D2 and the surface film F2 are the same as the device layer D1 and the surface film F1 of the first wafer W1, respectively. The surface film F1 of the first wafer W1 and the surface film F2 of the second wafer W2 are then bonded together. The position of the laser absorption layer P is not limited to that in the above embodiment, and may be formed, for example, between the device layer D2 and the surface film F2.

[0015] 2, the wafer processing system 1 has a configuration in which a carry-in / out block 10, a transfer block 20, and a processing block 30 are integrally connected. The carry-in / out block 10 and the processing block 30 are provided around the transfer block 20. Specifically, the carry-in / out block 10 is disposed on the negative Y-axis side of the transfer block 20. A laser irradiation device 31 (described later) and a separation device 32 (described later) of the processing block 30 are disposed on the negative X-axis side of the transfer block 20, a first cleaning device 33 (described later) and a second cleaning device 34 (described later) are disposed on the positive X-axis side of the transfer block 20, and an inversion device 35 (described later) is disposed on the positive Y-axis side of the transfer block 20.

[0016] The carry-in / out block 10 carries in and out cassettes Ct, Cw1, and Cw2, each capable of accommodating a plurality of overlapping wafers T, a plurality of first wafers W1, and a plurality of second wafers W2, for example, between the outside and the block 10. A cassette mounting table 11 is provided in the carry-in / out block 10. In the illustrated example, the cassette mounting table 11 can mount a plurality of cassettes Ct, Cw1, and Cw2, for example, three cassettes Ct, Cw1, and Cw2, in a line in the X-axis direction. The number of cassettes Ct, Cw1, and Cw2 mounted on the cassette mounting table 11 is not limited to that in this embodiment and can be determined arbitrarily.

[0017] The transfer block 20 is provided with a wafer transfer device 22 serving as a substrate transfer mechanism that is movable on a transfer path 21 extending in the Y-axis direction. The wafer transfer device 22 has multiple, for example, three transfer arms 23a-23c (hereinafter, these may be collectively referred to as "transfer arms 23") that hold and transfer the overlapped wafer T, the first wafer W1, or the second wafer W2. Each transfer arm 23 has an adsorption portion 24 (see FIG. 3) on its holding surface that adsorbs and holds the overlapped wafer T, the first wafer W1, or the second wafer W2. Each transfer arm 23 is movable horizontally, vertically, around a horizontal axis, and around a vertical axis. The wafer transport device 22 is configured to transport the overlapped wafer T, the first wafer W1, and the second wafer W2 to the cassettes Ct, Cw1, and Cw2 on the cassette mounting table 11, the laser irradiation device 31, the separation device 32, the first cleaning device 33, the second cleaning device 34, and the inversion device 35.

[0018] As shown in FIG. 3 , the three transfer arms 23a to 23c are stacked in this order from top to bottom. Each of the transfer arms 23a to 23c is configured to be independently rotatable about a vertical axis. At least one of the three transfer arms 23a to 23c (the middle transfer arm 23b in the illustrated example) has a wafer holding surface provided with a plurality of, for example, three, guide pins 25. The guide pins 25 are arranged to surround the periphery of the overlapped wafer T when the overlapped wafer T is held by the transfer arm 23b. The guide pins 25 prevent the second wafer W2 from falling off the first wafer W1 due to inertial forces and the like associated with the transfer of the overlapped wafer T by the wafer transfer device 22, as described below. 3, at least one of the plurality of transfer arms 23a-23c (the uppermost transfer arm 23a in the illustrated example) has an adsorption portion 24, i.e., a holding surface, on its lower surface for adsorbing and holding the laminated wafer T, the first wafer W1, or the second wafer W2. The transfer arm 23a having the adsorption portion 24 on its lower surface adsorbs and holds the second wafer W2 (upper substrate) from above when the second wafer W2 is carried out from the separation device 32 described below. The configuration of the transfer arm 23 is not limited to that of this embodiment, and any configuration may be used.

[0019] The processing block 30 has a laser irradiation device 31, a separation device 32, a first cleaning device 33, a second cleaning device 34, and an inversion device 35. Note that the number and arrangement of the laser irradiation device 31, the separation device 32, the first cleaning device 33, the second cleaning device 34, and the inversion device 35 are not limited to those shown above.

[0020] The laser irradiation device 31 irradiates the inside of the overlapped wafer T, more specifically, the laser absorbing layer P of the second wafer W2 with laser light to reduce the bonding strength at the interface between the second wafer W2 and the laser absorbing layer P. In the technology of the present disclosure, the interface where the bonding strength has been reduced inside the overlapped wafer T (in this embodiment, the interface between the second wafer W2 and the laser absorbing layer P) may be referred to as a "separation surface."

[0021] 4 and 5, a transfer position A1 and a processing position A2 are set inside the laser irradiation device 31. The transfer position A1 is a position where a wafer can be transferred between the transfer arm 23 and a chuck 100 (described later), and where an image of the outer edge of the overlapped wafer T can be captured by an imaging mechanism 120 (described later). The processing position A2 is a position where laser light can be irradiated onto the overlapped wafer T (laser absorption layer P) from a laser irradiation unit 110 (described later).

[0022] The laser irradiation device 31 has a chuck 100 as a substrate holder that holds the overlapped wafer T on its upper surface. The chuck 100 has a wafer holding surface on its upper surface, and adsorbs and holds the entire back surface W1b of the first wafer W1 or a part of the radially inner side of the back surface W1b. Examples of the chuck 100 include an electrostatic chuck (ESC) and a vacuum chuck.

[0023] The chuck 100 is also provided with lifting pins 100a (see FIG. 16) for supporting and lifting the laminated wafer T from below. The lifting pins 100a are inserted into through-holes (see FIG. 16) formed through the chuck 100 and are configured to be freely raised and lowered.

[0024] Furthermore, the chuck 100 is provided with a plurality of, for example, three, wafer drop prevention pins 101 as pins for preventing the substrate from dropping, so as to surround the periphery of the overlapped wafer T on the holding surface along the radial direction. The wafer drop prevention pins 101 prevent the second wafer W2 from dropping from the first wafer W1 when the second wafer W2 is unintentionally separated from the first wafer W1 during or after irradiation with laser light due to, for example, centrifugal force accompanying rotation of the chuck 100 or inertial force accompanying movement.

[0025] There is no particular limitation on the arrangement of the wafer fall prevention pins 101. As an example, in this embodiment, the wafer fall prevention pins 101 are configured to be rotatable integrally with the chuck 100 by a rotation mechanism 104 described later, and are configured to be movable integrally with the chuck 100 in the Y-axis direction by a drive mechanism 105 described later, and further configured to be movable up and down integrally with the lift pins 100a described above in the Z-axis direction.

[0026] The chuck 100 is supported by a slider table 103 via an air bearing 102. A rotation mechanism 104 is provided on the underside of the slider table 103. The rotation mechanism 104 has a built-in motor, for example, as a drive source. The chuck 100 is configured to be rotatable about the θ-axis (vertical axis) via the air bearing 102 by the rotation mechanism 104. The slider table 103 is configured to be movable between the transfer position A1 and the processing position A2 by a drive mechanism 105 provided on the underside thereof along rails 107 that are provided on a base 106 and extend in the Y-axis direction. The drive source of the drive mechanism 105 is not particularly limited, but a linear motor, for example, is used.

[0027] A laser irradiation unit 110 is provided above the chuck 100 at the processing position A2. The laser irradiation unit 110 includes a laser head 111, an optical system 112, and a lens 113.

[0028] The laser head 111 has a laser oscillator (not shown) that oscillates a laser beam in pulses. This laser beam is a so-called pulse laser. In this embodiment, the laser beam is a CO ２ Laser light, CO ２ The wavelength of the laser light is, for example, 8.9 μm to 11 μm. The laser head 111 may also include other devices in addition to the laser oscillator, such as an amplifier.

[0029] The optical system 112 has an optical element (not shown) that controls the intensity and position of the laser light, and an attenuator (not shown) that attenuates the laser light to adjust the output. The optical system 112 may also be configured to be able to control the branching of the laser light.

[0030] The lens 113 irradiates the laser light onto the overlapped wafer T held by the chuck 100. The laser light emitted from the laser irradiation unit 110 passes through the second wafer W2 and is irradiated onto the laser absorption layer P. The lens 113 may be configured to be freely movable up and down by an elevation mechanism (not shown).

[0031] Moreover, an imaging mechanism 120 serving as a detection mechanism is provided above the chuck 100 at the delivery position A1. The imaging mechanism 120 includes, for example, one or more cameras 121 selected from a macro camera, a micro camera, or the like, and a calculation unit 122. The imaging mechanism 120 may be configured to be movable in the Y-axis direction and the Z-axis direction by an elevator mechanism (not shown) or a moving mechanism (not shown).

[0032] The camera 121 serving as an acquisition unit captures an image of the outer edge of the overlapped wafer T held on the chuck 100. The camera 121 is equipped with, for example, a coaxial lens, irradiates infrared light (IR), and receives reflected light from an object. By capturing an image of the outer edge of the overlapped wafer T in this manner, the camera 121 acquires positional information of the overlapped wafer T (at least the second wafer W2) on the chuck 100. The calculation unit 122 serving as a determination unit detects the amount of eccentricity of the second wafer W2 relative to the first wafer W1 (the amount of misalignment in the horizontal direction (the direction along the separation plane): see FIG. 6 ) based on the positional information of at least the second wafer W2 acquired from the image data captured by the camera 121. Details of a method for detecting the eccentricity of the first wafer W1 and the second wafer W2 using the imaging mechanism 120 will be described later. In FIG. 6, in order to clearly show the eccentricity of the first wafer W1 and the second wafer W2, the chuck 100 does not have the wafer drop prevention pins 101 described above, and the eccentricity occurring in the first wafer W1 and the second wafer W2 is shown to be larger than it actually is.

[0033] The calculation unit 122 may be provided independently of the imaging mechanism 120 as described above, or may be included in the control device 40 described later. The imaging results obtained by the camera 121 and the eccentricity calculated by the calculation unit 122 may be output to the control device 40. In other words, the control device 40 may have the functions of an acquisition unit and a determination unit according to the technology of the present disclosure.

[0034] In this embodiment, the "acquisition unit" of the detection mechanism according to the technology of the present disclosure will be described as an example in which the "acquisition unit" is the "camera 121" that captures an image of at least the outer edge of the second wafer W2, but the configuration of the acquisition unit is not limited to this as long as it can at least acquire the position of the second wafer W2 on the chuck 100. Specifically, for example, the "acquisition unit" of the detection mechanism according to the technology of the present disclosure may be a length measurement sensor (displacement meter) that acquires position information of the second wafer W2 by measuring at least the distance to the second wafer W2.

[0035] In addition, in this embodiment, an example is given in which the acquisition unit (camera 121 or length measurement sensor) relating to the technology disclosed herein is positioned above the chuck 100 at the transfer position A1, but the acquisition unit may also be positioned to the side of the chuck 100 as long as it can acquire the position of at least the second wafer W2 on the chuck 100.

[0036] A transfer pad 130 is further provided above the chuck 100 at the transfer position A1. The transfer pad 130 is configured to be freely raised and lowered by an elevation mechanism (not shown). The transfer pad 130 has an adsorption surface on its underside for adsorbing and holding the first wafer W1. The transfer pad 130 transfers the second wafer W2 between the chuck 100 and the transfer arm 23 when the imaging mechanism 120 detects that eccentricity has occurred between the first wafer W1 and the second wafer W2 in the overlapped wafer T after the laser absorption layer P has been irradiated with laser light. The operation of the transfer pad 130 will be described in detail below.

[0037] The separating device 32 separates the second wafer W2 from the first wafer W1 using the interface between the second wafer W2 and the laser absorption layer P, which serves as a separation surface and whose bonding strength has been reduced by the laser irradiation device 31, as a base point.

[0038] 7, the separation device 32 includes a suction chuck 200 that suction-holds the backside W1b of the first wafer W1 from below, and a suction pad 210 that suction-holds the backside W2b of the second wafer W2 from above. The suction chuck 200 is provided with lift pins 200a for supporting the first wafer W1 from below and lifting and lowering it. The lift pins 200a are inserted through through-holes formed through the suction chuck 200 and are configured to be freely movable up and down. In the separation device 32, while the suction pad 210 suction-holds the second wafer W2, as shown in FIG. 7, the suction pad 210 is lifted to separate the second wafer W2 from the laser absorption layer P.

[0039] The configuration of the separating device 32 is not limited to this, and any configuration may be used as long as it can separate the second wafer W2 from the first wafer W1.

[0040] The first cleaning device 33 cleans the front surface W1a side of the first wafer W1 separated by the separating device 32. For example, a brush is brought into contact with the laser absorbing layer P on the front surface W1a side of the first wafer W1 to clean the laser absorbing layer P. Note that a pressurized cleaning liquid may be used to clean the first wafer W1. The first cleaning device 33 may also be configured to clean the back surface W1b of the first wafer W1 as well as the front surface W1a side.

[0041] The second cleaning device 34 cleans the front surface W2a of the second wafer W2 separated by the separating device 32. For example, a brush is brought into contact with the front surface W2a of the second wafer W2 to clean the front surface W2a. Note that a pressurized cleaning liquid may be used to clean the second wafer W2. The second cleaning device 34 may also be configured to clean the back surface W2b of the second wafer W2 as well as the front surface W2a.

[0042] In this embodiment, as described above, the first cleaning apparatus 33 for cleaning the first wafer W1 and the second cleaning apparatus 34 for cleaning the second wafer W2 are arranged independently, but the cleaning of the first wafer W1 and the cleaning of the second wafer W2 may be performed using the same cleaning apparatus.

[0043] The reversing device 35 reverses the top and bottom surfaces of the second wafer W2 after separation by the separating device 32. That is, the top and bottom surfaces of the second wafer W2 are reversed so that the top surface W2a, which is the surface of the second wafer W2 separated from the first wafer W1, faces upward after separation. The configuration of the reversing device 35 is not particularly limited.

[0044] The wafer processing system 1 described above is provided with a control device 40 as a control mechanism. 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 laminated wafer T in the wafer processing system 1. The program storage unit also stores a program for controlling the operation of the drive systems of the various processing devices and transport devices described above to realize the wafer processing described below in the wafer processing system 1. The program may be recorded on a computer-readable storage medium H and installed into the control device 40 from the storage medium H. The storage medium H may be temporary or non-temporary.

[0045] Next, a description will be given of wafer processing performed using the thus configured wafer processing system 1. In this embodiment, the first wafer W1 and the second wafer W2 are bonded together in a bonding device (not shown) external to the wafer processing system 1 to form an overlapped wafer T in advance.

[0046] First, a cassette Ct containing a plurality of overlapping wafers T is placed on the cassette placement table 11 of the carry-in / out block 10 .

[0047] Next, the transfer arm 23c of the wafer transfer device 22 takes out the overlapped wafer T from the cassette Ct and transfers it to the laser irradiation device 31. In the laser irradiation device 31, as shown in FIG. 8, the laser irradiation unit 110 irradiates the laser light L(CO ２ The laser absorption layer P is irradiated with pulsed laser light to reduce the bonding strength between the laser absorption layer P and the second wafer W2.

[0048] A specific wafer processing method in the laser irradiation device 31 will now be described.

[0049] In the laser irradiation device 31, the overlapped wafer T is transferred from the transfer arm 23c to the chuck 100 disposed at the transfer position A1, and is held by suction on the chuck 100 (step St1 in FIG. 9).

[0050] Next, the outer edge of the overlapped wafer T (first wafer W1 and second wafer W2) on the chuck 100, which is suction-held on the chuck 100, is imaged by the imaging mechanism 120 (step St2 in FIG. 9 ). Specifically, while the chuck 100 is being rotated, the camera 121 captures images of the outer edge of the overlapped wafer T in a 360-degree circumferential direction, thereby obtaining positional information of the overlapped wafer T (first wafer W1 and second wafer W2) on the chuck 100. The image capturing results by the camera 121 are output to the calculation unit 122.

[0051] The calculation unit 122 calculates the amount of eccentricity (see FIG. 6 ) of the first wafer W1 and the second wafer W2 before irradiation with the laser light L, based on position information of the first wafer W1 and the second wafer W2 on the chuck 100 obtained from the image capturing results by the camera 121. The calculated amount of eccentricity of the first wafer W1 and the second wafer W2 before irradiation with the laser light L is used to determine whether a misalignment occurs between the first wafer W1 and the second wafer W2 after irradiation with the laser light L, i.e., whether the second wafer W2 has been separated from the first wafer W1, by comparing the calculated amount of eccentricity of the first wafer W1 and the second wafer W2 before irradiation with the laser light L with the amount of eccentricity of the first wafer W1 and the second wafer W2 after irradiation with the laser light L, as described below. The calculated amount of eccentricity of the first wafer W1 and the second wafer W2 before irradiation with the laser light L may be output to the control device 40.

[0052] Furthermore, the calculation unit 122 may calculate the amount of eccentricity (amount of horizontal deviation) between the center of rotation of the chuck 100 and the center of the overlapped wafer T (first wafer W1 and / or second wafer W2) based on the image capture result by the camera 121. When eccentricity is found between the center of rotation of the chuck 100 and the center of the overlapped wafer T, it is desirable to perform eccentricity correction control in consideration of the amount of eccentricity calculated when irradiating the laser absorbent layer P with laser light L, which will be described later. The calculated amount of eccentricity between the center of rotation of the chuck 100 and the center of the overlapped wafer T (second wafer W2) may be output to the control device 40.

[0053] The control device 40 also acquires preset positions of a central region R1 and an outer peripheral region R2 (see FIG. 10 ) of the chuck 100, which will be described later, and sets the central region R1 and the outer peripheral region R2 on the overlapped wafer T, which is the target of irradiation with the laser light L, based on the image captured by the camera 121. More specifically, regions corresponding to the central region R1 and the outer peripheral region R2 (regions overlapping with the central region R1 and the outer peripheral region R2 in a plan view) are set within the surface of the overlapped wafer T held by the chuck 100. The positions of the central region R1 and the outer peripheral region R2 of the chuck 100 are set based on the center of rotation of the chuck 100, and may be acquired from positions previously output to the control device 40.

[0054] Next, the chuck 100 is moved to the processing position A2 by the driving mechanism 105. Subsequently, the laser irradiation unit 110 irradiates the laser light L(CO ２ The irradiation of the laser beam is started.

[0055] In the laser irradiation apparatus 31 according to this embodiment, the overlapped wafer T held by the chuck 100 is rotated by the rotation mechanism 104, and the overlapped wafer T is moved in the Y-axis direction by the drive mechanism 105 while being irradiated with pulsed laser light L. This causes the irradiation position of the laser light L to move from the outer side toward the inner side in the radial direction relative to the laser absorbing layer P, resulting in the laser light L being irradiated in a spiral pattern in a plan view, as shown in FIG. 10 . In this case, if the intervals at which the laser light L is irradiated are to be kept constant in order to uniformly separate the second wafer W2 from the laser absorbing layer P within the wafer surface, the peripheral speed of the overlapped wafer T at the irradiation position of the laser light L decreases as the irradiation position of the laser light L moves from the outer side toward the inner side in the radial direction, more specifically, as it approaches the rotation center of the chuck 100, and therefore it is necessary to increase the rotation speed of the overlapped wafer T. However, if the rotation speed of the overlapped wafer T is increased in this manner, there is a risk that the second wafer W2 may unexpectedly separate from the first wafer W1 due to centrifugal force caused by the rotation of the overlapped wafer T, even during irradiation with the laser light L. Therefore, in this embodiment, the overlapped wafer T is rotated when irradiating the outer peripheral region R2 of the chuck 100 (see FIG. 10 ), where the peripheral speed of the overlapped wafer T is relatively fast, with the laser light L, and the laser light L is scanned while the rotation of the overlapped wafer T is stopped when irradiating the central region R1 of the chuck 100 (see FIG. 10 ), where the peripheral speed of the overlapped wafer T is slow.

[0056] The central region R1 of the chuck 100, through which the laser beam L is scanned, is set in advance prior to wafer processing in the laser irradiation device 31 as a circular region having a desired diameter based on the center of rotation of the chuck 100, as described above. The diameter of the central region R1 is, for example, the radial position at which the relative rotation speed of the chuck 100 with respect to the lens 113 of the laser irradiation unit 110 reaches an upper limit; in other words, the limit position at which the laser beams L do not overlap. The diameter of the central region R1 is, for example, approximately 10 mm. The outer peripheral region R2, through which the chuck 100 rotates when irradiated with the laser beam L, is set to a region radially outward of the central region R1.

[0057] When irradiating the laser absorbing layer P with the laser light L, first, the laser light L is irradiated onto the overlapped wafer T (laser absorbing layer P) in a region corresponding to the outer peripheral region R2 (step St3 in FIG. 9 ). At this time, in the laser irradiation device 31, while irradiating the laser light L in pulses from the laser irradiation unit 110 as described above, the chuck 100 (overlapped wafer T) is rotated and the chuck 100 (overlapped wafer T) is moved in the Y-axis direction, so that the laser light L is irradiated spirally from the outer side to the inner side in the radial direction, as shown in FIG. 10 . At this time, the laser light L is irradiated from the back surface W2b side (the side opposite to the holding surface) of the second wafer W2 as shown in FIG. 8 , passes through the second wafer W2, and is absorbed by the laser absorbing layer P. This reduces the bonding strength at the interface between the laser absorbing layer P and the second wafer W2. In the embodiments, the phrase "reduced bonding strength" refers to a state in which the bonding strength is reduced at least compared to before the irradiation of the laser light L. More specifically, this refers to a bonding strength that prevents the second wafer W2 from shifting (separating) horizontally due to the centrifugal force associated with the rotation of the chuck 100 or the inertial force associated with the movement, and that allows the second wafer W2 to be properly separated from the first wafer W1 in the separation device 32 described below.

[0058] After the irradiation of the region corresponding to the outer peripheral region R2 with the laser light L (reducing the bonding strength between the second wafer W2 and the laser absorbing layer P), the region corresponding to the central region R1 of the overlapped wafer T (laser absorbing layer P) is irradiated with the laser light L (step St4 in FIG. 9 ). When the region corresponding to the central region R1 is irradiated with the laser light L, the rotation of the chuck 100 is stopped. Then, while the laser irradiation unit 110 irradiates the laser light L in pulses, scanning of the irradiation position of the laser light L in the X-axis direction and movement of the chuck 100 (overlapping wafer T) in the Y-axis direction by the drive mechanism 105 are alternately and repeatedly performed (see FIG. 10 ).

[0059] In order to improve the throughput of wafer processing, the laser light L may be branched by the optical system 112 described above, and the laser light L may be simultaneously irradiated onto a plurality of points on the laser absorbing layer P. In the example shown in Fig. 10, when the region corresponding to the central region R1 is irradiated with the laser light L, scanning of the irradiation position in the X-axis direction and movement in the Y-axis direction are alternately repeated, but the laser light L may be irradiated in a spiral manner, as with the region corresponding to the outer circumferential region R2. Alternatively, although not shown, the laser light L may be irradiated in an annular manner concentrically with the overlapped wafer T (laser absorbing layer P).

[0060] Here, when the laser absorbing layer P is irradiated with the laser light L in a spiral manner in the outer peripheral region R2 as described above, a region that is not irradiated with the laser light L for up to about one revolution in the circumferential direction is generated near the boundary between the outer peripheral region R2 and the central region R1, as shown in Fig. 11. When a region that is not irradiated with the laser light L is generated in the surface of the laser absorbing layer P in this way, there is a risk that the separation device 32 will not be able to properly separate the laser absorbing layer P from the second wafer W2 at a portion corresponding to the unirradiated region.

[0061] Therefore, in the laser irradiation apparatus 31 according to this embodiment, before switching the irradiation of the laser light L from the outer peripheral region R2 to the central region R1, in other words, before stopping the rotation of the chuck 100 to irradiate the central region R1 with the laser light L, the laser absorbing layer P is irradiated with the laser light L concentrically so as to surround the periphery of the central region R1, as shown in Fig. 12. More specifically, when irradiating the outer peripheral region R2 with the laser light L, the chuck 100 (superimposed wafer T) is rotated and moved in the Y-axis direction as described above to irradiate the laser light L in a spiral manner, but in the vicinity of the boundary between the outer peripheral region R2 and the central region R1, the rotation of the chuck 100 (superimposed wafer T) is continued while the movement in the Y-axis direction is stopped, so that the laser absorbing layer P is irradiated with the laser light L concentrically.

[0062] Note that the concentric irradiation of the laser light L onto the laser absorbing layer P may be performed only once around the central region R1 as shown in Fig. 12. Alternatively, as shown in Fig. 13, while the laser irradiation unit 110 is irradiating the laser light L in pulses, the rotation of the chuck 100 (superimposed wafer T) by the rotation mechanism 104 and the movement of the chuck 100 (superimposed wafer T) in the Y-axis direction by the drive mechanism 105 may be alternately repeated, thereby performing concentric irradiation of the laser light L multiple times in the radial direction. Furthermore, if the laser absorbing layer P and the second wafer W2 can be appropriately separated, the concentric irradiation of the laser light L may be stopped after one revolution or less in the circumferential direction (270 degrees in the circumferential direction in the example of Fig. 14) in order to prevent the device layer from being affected by overlapping irradiation positions of the laser light L, as shown in Fig. 14.

[0063] Furthermore, by irradiating the laser light L concentrically in this manner near the boundary between the peripheral region R2 and the central region R1, the size of the unirradiated region that occurs in the laser absorption layer P can be reduced, and therefore, separation of the laser absorption layer P and the second wafer W2 can be more appropriately performed.

[0064] 12, 13, and 14, for clarity of illustration, the spirally machined portion in the outer peripheral region R2 is shown by a broken line and the concentrically machined portion is shown by a dotted line, but in reality, the irradiation interval of the laser light L in the spirally machined portion and the concentrically machined portion is constant.

[0065] 10 shows the laser beam L irradiated from the radially outer side (near the outer end of the laser absorption layer P) to the radially inner side (the boundary of the central region R1) of the outer peripheral region R2 all at once. However, in reality, even during irradiation of the outer peripheral region R2 with the laser beam L, conditions related to the irradiation of the laser beam L, such as the frequency of the laser beam L, the rotation speed of the chuck 100, and the horizontal movement speed of the chuck 100, may be changed to maintain a constant interval between irradiations of the laser beam L. Alternatively, multiple regions with different conditions related to the irradiation of the laser beam L may be generated within the outer peripheral region R2. In this case, as shown in the comparative example of FIG. 15 , if the rotation of the chuck 100 is stopped and restarted each time the irradiation conditions of the laser beam L are changed, in other words, if the irradiation conditions of the laser beam L are changed while the chuck 100 is stopped, the time required for the laser processing increases because of the time required for acceleration and deceleration associated with the stopping and restarting of the rotation.

[0066] Therefore, in the laser irradiation apparatus 31 according to this embodiment, when the irradiation conditions of the laser light L are changed during irradiation of the outer peripheral region R2 with the laser light L, it is desirable to stop only the irradiation of the laser light L onto the laminated wafer T and the horizontal movement of the chuck 100, while continuing the rotation of the chuck 100. By continuing the rotation of the chuck 100 in this way when the irradiation conditions of the laser light L are changed, the time required for accelerating and decelerating the rotational speed of the chuck 100 can be reduced, as in the example of the present application shown in FIG.

[0067] Furthermore, when the chuck 100 is continuously rotated to change the irradiation conditions of the laser light L, the irradiation restart position of the laser light L after the change of the irradiation conditions may be the same as the irradiation end position of the laser light L before the change of the irradiation conditions, or may be a different position as long as the irradiation positions of the laser light L do not overlap. When the irradiation restart position and the irradiation end position of the laser light L are the same, after the change of the irradiation conditions of the laser light L, the irradiation of the laser light L is not resumed until the rotation of the chuck 100 brings the irradiation end position directly below the irradiation of the laser light L. In this case, the interval between the irradiation of the laser light L can be controlled to be constant over the entire surface of the laser absorbing layer P, and the separation of the second wafer W2 and the laser absorbing layer P can be controlled uniformly within the wafer surface. On the other hand, when the irradiation restart position and the irradiation end position of the laser light L are different, after the change of the irradiation conditions of the laser light L, the irradiation of the laser light L is resumed promptly at a position where the irradiation positions of the laser light L do not overlap. In this case, the waiting time until the start of irradiation of the laser light L is reduced, thereby further shortening the time required for laser processing.

[0068] After the laser light L is irradiated onto the central region R1 and the peripheral region R2 and the bonding strength between the second wafer W2 and the laser absorption layer P is reduced over the entire surface, the driving mechanism 105 then moves the chuck 100 (superimposed wafer T) to the transfer position A1.

[0069] Next, at the transfer position A1, the outer edge of the overlapped wafer T held by suction on the chuck 100 is imaged using the imaging mechanism 120 (step St5 in FIG. 9 ). Specifically, while the chuck 100 is rotating, the camera 121 captures images of the outer edge of the overlapped wafer T in a 360-degree circumferential direction, thereby acquiring position information of the overlapped wafer T (the first wafer W1 and the second wafer W2) on the chuck 100. The image capturing results by the camera 121 are output to the calculation unit 122. The calculation unit 122 calculates the amount of eccentricity (see FIG. 6 ) of the first wafer W1 and the second wafer W2 after irradiation with the laser light L based on the position information obtained from the image capturing results by the camera 121. The calculated amount of eccentricity of the first wafer W1 and the second wafer W2 after irradiation with the laser light L may be output to the control device 40.

[0070] The control device 40 calculates the difference between the amount of eccentricity of the first wafer W1 and the second wafer W2 before irradiation with the output laser light L and the amount of eccentricity of the first wafer W1 and the second wafer W2 after irradiation with the laser light L, and determines whether the second wafer W2 has been separated from the first wafer W1 based on the difference value (step St6 in FIG. 9).

[0071] In the wafer processing system 1 according to this embodiment, the overlapped wafer T, in which the bonding strength between the second wafer W2 and the laser absorbing layer P has decreased, is separated into the first wafer W1 and the second wafer W2 in a separation device 32 provided outside the laser irradiation device 31. However, as described above, if the bonding strength between the second wafer W2 and the laser absorbing layer P is decreased by irradiation with laser light L, the second wafer W2 may be separated from the laser absorbing layer P (first wafer W1) before being transferred to the separation device 32 due to the inertial force generated when the second wafer W2 is moved to the transfer position A1 by the drive mechanism 105 and the centrifugal force generated by the rotation of the chuck 100. If the second wafer W2 is separated in this way before being transferred to the separation device 32, not only may the overlapped wafer T not be able to be properly transferred to the separation device 32, but also the second wafer W2 may fall, causing problems within the system.

[0072] In this regard, in the laser irradiation apparatus 31 according to this embodiment, in step St6, it is possible to determine whether the second wafer W2 has been separated from the first wafer W1 before transferring the overlapped wafer T to the separation device 32. This prevents the wafer transfer device 22 from attempting to transfer the overlapped wafer T in a state in which the second wafer W2 has been separated from the first wafer W1 to the separation device 32, thereby reducing the risk of the second wafer W2 falling within the system.

[0073] 4 and 5 , in this embodiment, a plurality of, at least three, wafer drop prevention pins 101 are provided so as to surround the periphery of the overlapped wafer T held by the chuck 100. This prevents the second wafer W2 from dropping within the laser irradiation device 31 even if the second wafer W2 is separated from the first wafer W1 after the laser absorption layer P is irradiated with the laser light L.

[0074] If it is determined in step St6 that the second wafer W2 has been separated from the first wafer W1, the transfer pad 130 is first raised while the back surface W2b of the second wafer W2 is held by suction to remove the second wafer W2 from the first wafer W1 (step St7 in FIG. 9 ). Next, the first wafer W1 on the chuck 100 is transferred to the transfer arm 23c of the wafer transfer device 22, and the first wafer W1 is unloaded from the laser irradiation device 31 (step St8 in FIG. 9 ). At this time, if eccentricity (misalignment) of the first wafer W1 relative to the chuck 100 is detected in step St2, the insertion position of the transfer arm 23c may be adjusted in accordance with the amount of eccentricity. Next, the second wafer W2 held by suction on the transfer pad 130 is transferred to the transfer arm 23a of the wafer transfer device 22, and the second wafer W2 is transferred out of the laser irradiation device 31 (step St9 in FIG. 9 ). At this time, in order to hold by suction the back surface W2b of the second wafer W2 (the surface opposite to the side separated from the first wafer W1), it is desirable to use the transfer arm 23a that holds the second wafer W2 by suction from above. Note that the second wafer W2 may be transferred to the transfer arm 23a via the chuck 100.

[0075] The first wafer W1 unloaded from the laser irradiation device 31 is then transferred by the wafer transfer device 22 to the cassette Cw1 on the cassette mounting table 11. The second wafer W2 unloaded from the laser irradiation device 31 is inverted in the inverting device 35, i.e., the surface separated from the first wafer W1 faces upward, and then transferred by the wafer transfer device 22 to the cassette Cw2 on the cassette mounting table 11. At this time, the first wafer W1 and the second wafer W2 may be transferred to the cassettes Cw1 and Cw2 on the cassette mounting table 11 after their surfaces, that is, the front surfaces W1a and W2a, which are the surfaces on the separated side, are cleaned in the first cleaning device 33 and the second cleaning device 34, respectively.

[0076] On the other hand, if it is determined in step St6 that the second wafer W2 has not been separated from the first wafer W1, the overlapped wafer T is transferred from the chuck 100 to the transfer arm 23b of the wafer transfer device 22 and removed from the laser irradiation device 31 (step St10 in Figure 9).

[0077] Here, if the separation of the second wafer W2 cannot be properly detected even though the second wafer W2 has actually been separated from the first wafer W1 in the above-mentioned step St6, the second wafer W2 may fall within the system due to an impact applied to the overlapped wafer T when it is transferred from the chuck 100 to the transfer arm 23, or due to the inertial force when it is transferred by the transfer arm 23.

[0078] In this regard, in the laser irradiation apparatus 31 according to this embodiment, as described above, the wafer drop prevention pins 101 arranged to surround the periphery of the overlapped wafer T held by the chuck 100 are configured to be movable up and down in the Z-axis direction together with the lift pins 100a. The overlapped wafer T is transferred from the chuck 100 to the transfer arm 23b by supporting and lifting the overlapped wafer T from below with the lift pins 100a, inserting the transfer arm 23b between the holding surface of the chuck 100 and the lower surface of the overlapped wafer T (the back surface W1b of the first wafer W1), and then lowering the overlapped wafer T with the lift pins 100a. At this time, as shown in FIG. 16, by raising and lowering the wafer drop prevention pins 101 together with the lifting pins 100a, the overlapping wafer T can be surrounded by the wafer drop prevention pins 101 even when the wafer is being raised by the lifting pins 100a, thereby preventing the second wafer W2 from falling when being transferred from the chuck 100 to the transport arm 23b.

[0079] Furthermore, in the wafer processing system 1 according to this embodiment, when the overlapped wafer T after being irradiated with the laser light L is transported from the laser irradiation device 31 to the separation device 32, a transport arm 23b having guide pins 25 arranged on the holding surface so as to surround the periphery of the overlapped wafer T is used. This makes it possible to prevent the second wafer W2 from falling due to inertial force during transport of the overlapped wafer T from the laser irradiation device 31 to the separation device 32, even if the second wafer W2 has been separated from the first wafer W1.

[0080] The laminated wafer T unloaded from the laser irradiation device 31 is then transported to the separation device 32 by the wafer transport device 22. In the separation device 32, as shown in FIG. 7 , the back surface W1b of the first wafer W1 is suction-held by the suction chuck 200, and the back surface W2b of the second wafer W2 is suction-held by the suction pad 210. Thereafter, while the suction pad 210 is suction-holding the second wafer W2, the suction pad 210 is raised to separate the first wafer W1 and the second wafer W2. At this time, because the bonding strength at the interface between the laser absorption layer P and the second wafer W2 has been reduced by the irradiation of the laser light L as described above, the second wafer W2 can be separated without applying a large load.

[0081] As shown in FIG. 17 , the separated second wafer W2 is transferred from the suction pad 210 to the transfer arm 23a of the wafer transfer device 22 and transferred to the inverting device 35. Then, in the inverting device 35, the second wafer W2 is turned so that its front surface W2a faces upward, and then transferred to the second cleaning device 34. In the second cleaning device 34, the front surface W2a, which is the surface separated from the first wafer W1, is cleaned. The second cleaning device 34 may also clean the back surface W2b as well as the front surface W2a. Alternatively, separate cleaning units may be provided for cleaning the front surface W2a and the back surface W2b, respectively. The second wafer W2 cleaned by the second cleaning device 34 is then transferred to the cassette Cw2 on the cassette mounting table 11 by the wafer transfer device 22.

[0082] On the other hand, the first wafer W1 held by the suction chuck 200 is transferred to the transfer arm 23c as shown in FIG. 17 and transferred to the first cleaning device 33. This transfer by the transfer arm 23c may be performed simultaneously with or independently from the transfer of the second wafer W2 by the transfer arm 23a. In the first cleaning device 33, the front surface W1a of the first wafer W1, which is the surface separated from the second wafer W2, specifically the front surface of the laser absorbing layer P, is cleaned. Note that the first cleaning device 33 may also clean the back surface W1b of the first wafer W1 along with the front surface of the laser absorbing layer P. Alternatively, separate cleaning units may be provided for cleaning the front surface of the laser absorbing layer P and the back surface W1b of the first wafer W1. The first wafer W1 cleaned by the first cleaning device 33 is then transferred to the cassette Cw1 on the cassette mounting table 11 by the wafer transfer device 22.

[0083] Thus, a series of wafer processing steps in the wafer processing system 1 is completed.

[0084] In the laser irradiation apparatus 31 according to the above embodiment, as described above, separation of the second wafer W2 is detected based on the difference in the amount of eccentricity of the second wafer W2 relative to the first wafer W1 before and after irradiation of the overlapped wafer T (laser absorption layer P) with the laser light L. However, the configuration of the detection mechanism for the second wafer W2 and the detection method using the same are not limited, and at least one of the following configurations and methods may be used instead of or in addition to the above configurations and methods.

[0085] (1) As described above, if the second wafer W2 is actually separated from the first wafer W1 after irradiation of the laser light L onto the overlapped wafer T (laser absorption layer P) but no eccentricity (horizontal misalignment) occurs, separation of the second wafer W2 cannot be properly detected. Therefore, after irradiation of the overlapped wafer T with the laser light L in the laser irradiation device 31, a load may be applied to the overlapped wafer T when the chuck 100 moves from the processing position A2 to the transfer position A1, thereby shifting the second wafer W2 from the first wafer W1 (moving the second wafer W2 in the horizontal direction). More specifically, for example, the acceleration applied to the movement of the chuck 100 from the processing position A2 to the transfer position A1 after irradiation with the laser light L may be made larger than the acceleration applied to the movement of the chuck 100 from the transfer position A1 to the processing position A2 before irradiation with the laser light L, thereby applying an inertial force as a load to the overlapped wafer T. At this time, the magnitude of the load applied to the overlapped wafer T after irradiation with the laser light L is controlled to a magnitude that allows the separated second wafer W2 to be shifted on the first wafer W1, and that does not cause the second wafer W2 to shift on the first wafer W1 when the second wafer W2 is not separated (the second wafer W2 is not separated).

[0086] According to the above method (1), eccentricity (misalignment in the horizontal direction) is intentionally generated between the first wafer W1 and the second wafer W2 by deliberately applying a load to the overlapped wafer T after irradiation with the laser light L. This makes it possible to avoid the above-described state in which no eccentricity occurs even though the second wafer W2 is separated from the first wafer W1, and as a result, it is possible to more appropriately suppress the risk of the second wafer W2 falling off the first wafer W1 within the system.

[0087] Furthermore, according to the method (1), intentionally causing eccentricity in the first wafer W1 and the second wafer W2 can reduce the takt time associated with processing in the laser irradiation device 31. Specifically, according to the method (1), intentionally causing eccentricity in the first wafer W1 and the second wafer W2 makes it possible to detect eccentricity by capturing an area image of at least a portion of the outer edge, for example, only one location in the circumferential direction, instead of capturing an image of the outer edge in the 360-degree circumferential direction of the overlapped wafer T. This makes it possible to eliminate the time required to capture an image of the outer edge after irradiating at least the overlapped wafer T (laser absorption layer P) with laser light L, thereby reducing the takt time.

[0088] 4 and 5, in the laser irradiation device 31, a plurality of, for example, three, contact sensors 108 as detection units and a calculation unit 109 as a determination unit for determining separation of the second wafer W2 by the contact sensors 108 may be arranged so as to surround the periphery of the laminated wafer T on the holding surface of the chuck 100 as shown in FIG. 18. In this case, instead of or in addition to the imaging mechanism 120 according to the above embodiment, the contact sensors 108 and the calculation unit 109 constitute a detection mechanism according to the technology of the present disclosure. Note that the calculation unit 109 may be arranged independently in the laser irradiation device 31 or may be included in the control device 40.

[0089] According to the above configuration (2), separation of the second wafer W2 can be detected simply by determining whether or not there is contact between the contact sensor 108 and the second wafer W2, instead of capturing an image of the outer edge of the overlapped wafer T (laser absorbing layer P) after irradiation with the laser light L. This makes it possible to omit capturing an image of the outer edge by the imaging mechanism 120 after irradiation of the overlapped wafer T (laser absorbing layer P) with the laser light L, thereby reducing the tact time related to processing in the laser irradiation device 31.

[0090] In the wafer processing system 1 according to the technique of the present disclosure, both the imaging mechanism 120 as a detection mechanism and the contact sensor 108 may be disposed in the laser irradiation device 31. In this case, both the detection of separation between the first wafer W1 and the second wafer W2 by the imaging mechanism 120 and the detection by the contact sensor 108 may be performed. In this case, when contact between the contact sensor 108 and the second wafer W2 is detected, the detection of separation between the first wafer W1 and the second wafer W2 by the imaging mechanism 120 (taking an image of the outer edge of the overlapped wafer T) may be omitted.

[0091] (3) In the above embodiment, separation of the second wafer W2 is detected based on the difference in the amount of eccentricity between the first wafer W1 and the second wafer W2 before and after irradiation with the laser light L, which is obtained by imaging the outer edge portions of the overlapped wafer T (first wafer W1 and second wafer W2) using the imaging mechanism 120. However, the imaging mechanism 120 does not necessarily have to image the outer edge portions of the overlapped wafer T (first wafer W1 and second wafer W2) before and after irradiation with the laser light L, and may image the outer edge portions of the overlapped wafer T (first wafer W1 and second wafer W2) only after irradiation with the laser light L.

[0092] Even with the above method (3), if an image of the outer edge of the overlapped wafer T (first wafer W1 and second wafer W2) after irradiation with laser light L can be captured and the amount of eccentricity (amount of horizontal positional misalignment) between the first wafer W1 and the second wafer W2 can be obtained, separation of the second wafer W2 can be determined based on the amount of eccentricity.

[0093] (4) In the above embodiment, the separation of the second wafer W2 is detected based on the difference in the amount of eccentricity between the first wafer W1 and the second wafer W2 before and after irradiation with the laser light L, which is obtained by capturing images of the outer edges of the overlapped wafer T (the first wafer W1 and the second wafer W2) using the imaging mechanism 120. However, depending on factors such as the angle of view and imaging magnification of the imaging mechanism 120, the imaging mechanism 120 may not be able to capture an image of the outer edge of the first wafer W1 serving as the lower substrate on the chuck 100.

[0094] Therefore, in the wafer processing system 1 according to the technology of the present disclosure, only the outer edge of the second wafer W2 serving as the upper substrate may be imaged by the imaging mechanism 120. In this case, positional information of the second wafer W2 on the chuck 100 before and after irradiation with the laser light L is obtained from the imaging results obtained by the imaging mechanism 120, and the horizontal eccentricity (misalignment) of the center (more specifically, the center of rotation) of the second wafer W2 relative to the center of the chuck 100 before and after irradiation with the laser light L is detected. Then, a difference value is calculated between the eccentricity of the center of the second wafer W2 relative to the center of the chuck 100 before irradiation with the laser light and the eccentricity of the center of the second wafer W2 relative to the center of the chuck 100 after irradiation with the laser light, and separation of the second wafer W2 can be determined based on the difference value.

[0095] According to the above method (4), even if the imaging mechanism 120 cannot properly image the outer edge of the overlapped wafer T (first wafer W1 and second wafer W2), the separation of the second wafer W2 can be detected by acquiring positional information of at least the second wafer W2.

[0096] (5) In the above embodiment, the amount of eccentricity between the first wafer W1 and the second wafer W2 is calculated and separation of the second wafer W2 is detected by capturing images of the outer edges of the overlapped wafer T (the first wafer W1 and the second wafer W2) over 360 degrees in the circumferential direction using the imaging mechanism 120. However, the imaging of the outer edges of the overlapped wafer T (the first wafer W1 and the second wafer W2) by the imaging mechanism 120 does not necessarily have to be performed over 360 degrees in the circumferential direction. Separation of the second wafer W2 can also be detected by capturing images of at least two locations in the circumferential direction of the overlapped wafer T (for example, a point at a reference position of 0 degrees in the circumferential direction and a point at 90 degrees in the circumferential direction from the reference position).

[0097] According to the method (5), separation of the second wafer W2 can be detected by capturing area images of the outer edge of the overlapped wafer T at two locations in the circumferential direction, instead of capturing images of the outer edge of the overlapped wafer T in the 360-degree circumferential direction. This reduces the time it takes for the imaging mechanism 120 to capture images of the outer edge after irradiation with the laser light L, thereby reducing the takt time required for processing in the laser irradiation device 31.

[0098] (6) In the above embodiment, the laser irradiation unit 110 irradiates the central region R1 and the outer peripheral region R2 with the laser light L, thereby reducing the bonding strength over the entire surface between the second wafer W2 and the laser absorbing layer P. However, when the bonding strength over the entire surface between the second wafer W2 and the laser absorbing layer P is reduced in this manner, there is a risk that the second wafer W2 may fall due to the inertial force during transportation of the overlapped wafer T, as described above.

[0099] Therefore, in the wafer processing system 1 according to the technique of the present disclosure, the irradiation of the laser light L may be stopped in at least a part of the region at the interface between the second wafer W2 and the laser absorbing layer P, and the bonding strength between the second wafer W2 and the laser absorbing layer P may be maintained in the at least part of the region not irradiated with the laser light L. More specifically, in the wafer processing system 1, as shown in Fig. 19 , a region where the bonding strength between the second wafer W2 and the laser absorbing layer P is not reduced may be formed in a part of an outermost region R0 (see (a) of Fig. 19 ) set at the outermost position of the outer periphery region R2, or in a central region R3 (see (b) of Fig. 19 ) set near the center position of the central region R1, at the interface between the second wafer W2 and the laser absorbing layer P.

[0100] According to the method (6), by forming an area in which the bonding strength is not reduced (the laser light L is not irradiated) in at least a part of the interface between the second wafer W2 and the laser absorption layer P, the second wafer W2 is not separated from the first wafer W1 in the area, and therefore, it is possible to prevent the second wafer W2 from falling due to inertial forces acting on the overlapped wafer T, etc.

[0101] In the wafer processing system 1 according to the technology of the present disclosure, by using at least one of the above-described embodiments and methods (1) to (6), the separation of the second wafer W2 is detected prior to the removal of the overlapped wafer T from the laser irradiation device 31, thereby reducing the risk of the second wafer W2 falling from the first wafer W1 within the system.

[0102] Furthermore, even when at least one of the above methods (1) to (6) is performed in this manner, the “acquisition unit” of the detection mechanism can use a length measuring sensor (displacement meter) instead of the camera 121 as described above.

[0103] In the above embodiment, when separation of the second wafer W2 is detected in step St6 as shown in FIG. 9, the first wafer W1 and the second wafer W2 are sequentially carried out from the laser irradiation device 31 (steps St8 and St9). However, the operation when separation is detected is not limited to this.

[0104] For example, instead of independently unloading the first wafer W1 and the second wafer W2 from the laser irradiation device 31 as described above, the first wafer W1 and the second wafer W2 may be unloaded together from the laser irradiation device 31 using the transfer arm 23b equipped with the guide pins 25, as in step St10. In this case, in order to prevent the second wafer W2 from falling from the first wafer W1, it is desirable to control the lifting and lowering speed of the overlapped wafer T by the lift pins 100a and the transfer speed of the overlapped wafer T by the wafer transfer device 22 to be slower than the specified speed, which is the movement speed under normal circumstances (when separation of the second wafer W2 is not detected in step St6). Furthermore, for example, if separation of the first wafer W1 and the second wafer W2 is detected in step St6 and it is determined that it is difficult to transfer the overlapped wafer T by the wafer transfer device 22, the control device 40 may issue an alarm and stop subsequent processing. In this case, the overlapped wafer T may be manually removed from the laser irradiation device 31 by an operator.

[0105] In the above embodiment, the wafer processing method according to the present disclosure is applied when performing laser lift-off to separate the second wafer W2 from the laser absorption layer P. However, the technology according to the present disclosure can be applied to any case in which at least a part of the first wafer W1 and / or the second wafer W2 is separated from the overlapped wafer T in which the first wafer W1 and the second wafer W2 are bonded together.

[0106] For example, in a semiconductor device manufacturing process, a modified layer is formed inside a silicon substrate of a wafer having a plurality of electronic circuits or other devices formed on its surface by irradiating the silicon substrate with laser light along the surface direction, and the modified layer is used as a separation surface to separate the wafer, thereby thinning the wafer. YAG laser light is used as the laser light. The disclosed technology can also be applied to forming such a modified layer as a separation surface that serves as the starting point for wafer thinning. Furthermore, the technology disclosed herein can also be applied to a debonder technology for separating a first wafer W1 and a second wafer W2 from each other in a bonded wafer T.

[0107] In addition, when laser light is irradiated into the inside of a silicon substrate to form a modified layer as described above and the wafer is separated using the modified layer as a base point, the laser irradiation device 31 is only required to detect the positional misalignment between the lower wafer held and left on the chuck 100 and the upper wafer to be removed by separation, instead of the horizontal positional misalignment between the first wafer W1 and the second wafer W2 shown in the above embodiment.

[0108] Specifically, for example, instead of the imaging mechanism 120 or the length measurement sensor, a spectroscopic interferometer may be arranged in the laser irradiation device 31, and the space generated at the interface between the first wafer W1 and the second wafer W2 (more specifically, the interface between the second wafer W2 and the laser absorption layer P) may be detected in the thickness direction of the overlapping wafer T (position information in the height direction of the overlapping wafer T), thereby determining whether the second wafer W2 has been separated from the first wafer W1.

[0109] 20, a laser irradiation device 310 according to another embodiment is provided with a spectroscopic interferometer 320. The spectroscopic interferometer 320 has a head 321 and an analyzing unit 322.

[0110] The head 321 has an irradiation unit (not shown) that irradiates measurement light onto the overlapped wafer T on the chuck 100, and a spectroscopic unit (not shown) that receives measurement light (reflected light) reflected at different height positions (a first height position H1 and a second height position H2: see FIGS. 21 and 22) of the overlapped wafer T and detects interference between the reflected light. As the measurement light irradiated from the irradiation unit, light that is transparent to the second wafer W (silicon) is arbitrarily selected.

[0111] The analysis unit 322 calculates the distance between the first height position H1 and the second height position H2 by detecting interference between the reflected light from the first height position H1 and the second height position H2 detected by the head 321. The analysis unit 322 may be incorporated into the control device 40.

[0112] Next, a method for determining whether the second wafer W2 has been separated from the first wafer W1 using the spectroscopic interferometer 320 will be described.

[0113] The central region R1 and the outer peripheral region R2 are irradiated with laser light L in the same manner as in the above embodiment, and the overlapped wafer T, in which the bonding strength between the second wafer W2 and the laser absorption layer P is reduced over the entire surface, is moved by the drive mechanism 105 below the spectroscopic interferometer 320. Next, while the chuck 100 is rotated, as shown in Fig. 21 , measurement light L2 from the irradiation unit of the head 321 is irradiated toward the overlapped wafer T, and reflected light from the overlapped wafer T is made to enter the spectroscopic unit. When the spectroscopic unit detects interference of the reflected light over the entire surface of the overlapped wafer T (reflection spectrum), it determines that the second wafer W2 has been separated from the first wafer W1.

[0114] However, as shown in the above embodiment, if the chuck 100 holding the overlapped wafer T in which the bonding strength between the second wafer W2 and the laser absorbing layer P has been reduced over the entire surfaces thereof is moved or rotated, there is a risk that the second wafer W2 may fall off the first wafer W1. In view of this, it is desirable to reduce the moving speed and rotation speed when moving or rotating the chuck 100 holding the overlapped wafer T in which the bonding strength between the second wafer W2 and the laser absorbing layer P has been reduced over the entire surfaces thereof. Alternatively, instead of moving or rotating the chuck 100, the spectroscopic interferometer 320 may be moved or rotated relatively above the chuck 100 (overlapped wafer T). Furthermore, for example, the spectroscopic interferometer 320 may be arranged alongside or integrally configured with the laser irradiation device 310, so that the process of reducing the bonding strength by the laser irradiation device 310 and the determination of separation by the spectroscopic interferometer 320 may be performed simultaneously or consecutively.

[0115] A more specific method for determining separation of the second wafer W2 and the first wafer W1 using the spectroscopic interferometer 320 will be described below. When the bonding strength at the interface between the second wafer W2 and the laser absorption layer P is reduced by irradiation with the laser light L and the second wafer W2 is separated from the first wafer W1, it is considered that a space S, which is a gap between the second wafer W2 and the first wafer W1, is formed at the separation surface between the second wafer W2 and the first wafer W1 (the interface between the second wafer W2 and the laser absorption layer P in the illustrated example), as shown in FIGS.

[0116] When a space S is generated at the interface between the second wafer W2 and the laser absorption layer P in this manner, the measurement light L2 is reflected at the upper and lower surfaces of this space, i.e., at a first height position H1 and a second height position H2, and reflected light L2a and L2b from these surfaces enter the spectroscopic unit, as shown in Fig. 21. When the spectroscopic unit detects interference (reflection spectrum) between the reflected light L2a and L2b, the analyzer 322 calculates the thickness t of the space S (the distance between the first height position H1 and the second height position H2) based on this. The calculated thickness t of the space S is output to the control device 40.

[0117] Based on this output thickness t, the control device 40 can determine whether or not a space S has been formed at the interface between the second wafer W2 and the laser absorbing layer P. If it is determined that a space S has been formed over the entire surface of the overlapped wafer T (laser absorbing layer P), it can be determined that the second wafer W2 and the laser absorbing layer P have been completely peeled off, and that the second wafer W2 has been separated from the first wafer W1.

[0118] In one example, whether or not a space S has formed at the interface (separation surface) between the second wafer W2 and the laser absorption layer P can be determined by comparing the measurement result (thickness t) obtained by the spectroscopic interferometer 320 after irradiating the overlapped wafer T with the laser light L with a preset first threshold. When the measurement result exceeds the preset first threshold, it is determined that the space S has been formed. The first threshold used for the comparison may be, for example, a value obtained by measuring the same overlapped wafer T before irradiating it with the laser light L by the laser irradiation device 31. That is, the first threshold may be used to compare the measurement result obtained when the laser light L is not irradiated (no space S has formed) with the measurement result obtained when the laser light L has been irradiated (space S has formed). Alternatively, the first threshold may be a value obtained in advance from a different wafer (e.g., a dummy wafer). That is, the first threshold may be used to compare the measurement result obtained from a different wafer whose bonding strength has been reduced by irradiating it with the laser light L with the measurement result obtained from an actual wafer whose bonding strength has been reduced by irradiating it with the laser light L.

[0119] The value used as the first threshold value may be the calculated thickness t of the space S. In this case, the first threshold value is a value at which it can be determined that the space S has been formed, and is a value greater than t>0, which is the thickness at which it is determined that the space S has been formed. The first threshold value used for comparison may be set to a value greater than 0.

[0120] When the region of the interface exceeding the first threshold satisfies a predetermined second threshold, the control device 40 determines that the second wafer W2 has not been separated from the first wafer W1 and that the second wafer W2 will not fall. The second threshold is set within a range in which the second wafer W2 is unlikely to fall from the first wafer W1 during subsequent transfer of the overlapped wafer T. The second threshold is set, for example, through a prior experiment or simulation. The value used as the second threshold can be the area ratio of the region in which the space S is formed to the total area of ​​the overlapped wafer T (laser absorption layer P) in a plan view.

[0121] It is desirable that the detection of reflected light from the overlapped wafer T using the spectroscopic interferometer 320 be performed on the entire surface of the overlapped wafer T (laser absorbing layer P) in order to properly detect separation of the second wafer W2 from the first wafer W1. However, for the purpose of shortening the time required for inspection and improving throughput, the detection may be performed on only a part of the irradiation pitch of the laser light L irradiated onto the laser absorbing layer P (for example, only a part in the radial or circumferential direction). Alternatively, for example, as shown in FIG. 19 , when a region that does not reduce the bonding strength is formed in a part of the interface between the second wafer W2 and the laser absorbing layer P, it is possible to inspect only this region that does not reduce the bonding strength, and if separation does not occur (if the thickness t = 0), it may be determined that the first wafer W1 and the second wafer W2 have not been separated.

[0122] In the above other embodiment, the case where the spectroscopic interferometer 320 for detecting separation between the first wafer W1 and the second wafer W2 is disposed inside the laser irradiation device 310 has been described as an example, but the spectroscopic interferometer 320 may be disposed outside the laser irradiation device 310. That is, in the technology according to the present disclosure, the laser irradiation device 31 and an inspection device (not shown) equipped with the spectroscopic interferometer 320 for detecting separation between the first wafer W1 and the second wafer W2 may be disposed independently in the wafer processing system 1.

[0123] In the above example, whether the second wafer W2 is separated from the first wafer W1 is determined by detecting the space S formed at the interface between the first wafer W1 and the second wafer W2 (by detecting that the thickness t is greater than 0), but the method of inspecting the separation state is not limited to this.

[0124] Specifically, in the overlapped wafer T in which a space S is formed at the interface between the first wafer W1 and the second wafer W2 in the laser irradiation device 310, it is considered that the height of the overlapped wafer T (more specifically, the height position of the back surface W2b of the second wafer W2) changes due to peeling between the second wafer W2 and the laser absorption layer P, as shown in Fig. 22. In Fig. 22, the position of the second wafer W2 before the formation of the space S is indicated by a dotted line, and the position of the second wafer W2 after the formation of the space S is indicated by a solid line.

[0125] Therefore, when determining whether or not the space S has been formed in order to grasp the separation state between the first wafer W1 and the second wafer W2, the height of the overlapped wafer T may be measured. Specifically, for example, an optical flat (reference horizontal plane) may be provided in the spectroscopic interferometer 320, and the interference (reflection spectrum) of light reflected from the optical flat and light reflected from the back surface W2b of the second wafer W2 may be detected. In this case, the difference in height between the reference horizontal plane and the overlapped wafer T before and after the formation of the space S is calculated, and if this difference has changed before and after the formation of the space S, it can be determined that the space S has been formed. Alternatively, if a region that does not reduce the bonding strength is formed in part of the interface between the second wafer W2 and the laser absorption layer P as shown in FIG. 19 , it is determined that the space S has not been formed if this region is at the same height as the optical flat.

[0126] Furthermore, when measuring the height of the overlapped wafer T (the height position of the back surface W2b of the second wafer W2) in this manner, instead of the thickness t of the space S, which is the measurement result used for comparison with the first threshold value in the above embodiment, the amount of change t2 in the height of the overlapped wafer T due to the formation of the space S (see FIG. 22) can be used as the measurement result used for comparison with the first threshold value.

[0127] Furthermore, for example, a displacement meter (not shown) may be provided above the chuck 100 instead of or in addition to the spectroscopic interferometer 320 to measure the distance from the displacement meter to the back surface W2b of the second wafer W2. In other words, the separation of the first wafer W1 and the second wafer W2 may be determined by detecting, for example, the amount of change in the distance to the back surface W2b of the second wafer W2 before and after the formation of the space S, or the difference between the distance to the back surface W2b in the region where the space S is formed and the distance to the back surface W2b in the region where the bonding strength is not reduced (see FIG. 19 ). In this case, the laser irradiation apparatus 310 shown in FIG. 20 can be configured simply by replacing the spectroscopic interferometer 320 with a displacement meter (length measuring sensor) not shown.

[0128] In the above-described laser irradiation device, the laser light L is sequentially irradiated onto a preset central region R1 and an outer peripheral region R2 (see FIG. 10 ) of the chuck 100. However, the determination of whether or not to irradiate the central region R1 with the laser light L may be made, for example, prior to irradiating the central region R1 with the laser light L.

[0129] Specifically, when irradiating the overlapped wafer T (laser absorption layer P) with the laser light L, first, position information of the outer peripheral region R2 is acquired prior to irradiating the outer peripheral region R2 with the laser light L. The acquired position information may be, for example, a displacement amount (the distance between an acquisition unit and the overlapped wafer T) obtained by a displacement meter such as a length measuring sensor. After the position information of the outer peripheral region R2 is acquired, irradiation of the outer peripheral region R2 with the laser light L is then started. The method of irradiating the outer peripheral region R2 with the laser light L is the same as the method of irradiating the laser light L described above. Next, prior to irradiating the central region R1 with the laser light L, the position information of the outer peripheral region R2 is reacquired. Note that this reacquisition of the position information may be performed by temporarily interrupting the laser processing (rotation of the overlapped wafer T and irradiation of the laser light L) prior to irradiating the central region R1 with the laser light L, or may be performed continuously during the laser processing of the outer peripheral region R2.

[0130] Here, if there is no change in the position information of the outer peripheral region R2 before and after irradiation of the laser light L to the outer peripheral region R2, or if there is no change equal to or greater than a predetermined threshold, it is considered that complete delamination has not occurred in the outer peripheral region R2 at the interface between the second wafer W2 and the laser absorption layer P, and that the bonding strength is still maintained. On the other hand, if there is a change equal to or greater than the threshold in the position information of the outer peripheral region R2 before and after irradiation of the laser light L, it is considered that delamination has occurred at the interface between the second wafer W2 and the laser absorption layer P for some reason during irradiation of the outer peripheral region R2 with the laser light L, and that the bonding strength has decreased.

[0131] Therefore, if the position information of the outer peripheral region R2 does not change by more than the threshold value before and after irradiation with the laser light L and it is considered that the bonding strength is maintained, the central region R1 is continuously irradiated with the laser light L. The overlapped wafer T, in which the bonding strength between the second wafer W2 and the laser absorption layer P has decreased, is then transferred to the separation device 32, where the first wafer W1 and the second wafer W2 are separated.

[0132] On the other hand, if the position information of the outer peripheral region R2 changes by a threshold value or more before and after irradiation with the laser light L and it is considered that the bonding strength has decreased, the central region R1 is not irradiated with the laser light L. Therefore, the bonding strength between the second wafer W2 and the laser absorption layer P in the central region R1 is maintained. In this case, the overlapped wafer T is recovered from the laser irradiation device without being transported to the separation device 32. At this time, the overlapped wafer T may be recovered into a cassette via the transport device, or may be manually removed from the laser irradiation device by an operator.

[0133] In this way, for example, by determining whether or not to irradiate laser light L onto the central region R1 depending on the peeling state of the peripheral region R2, complete peeling over the entire surface of the interface between the second wafer W2 and the laser absorption layer P, including the central region R1, can be suppressed, and the overlapped wafer T can be safely transported out without dropping the second wafer W2 within the laser irradiation device.

[0134] In this description, position information of the outer peripheral region R2 is acquired prior to irradiation of the laser light L onto the outer peripheral region R2, and the peeling state is determined by comparing the position information before irradiation with the laser light L with the position information after irradiation with the laser light L. However, if the peeling state in the outer peripheral region R2 can be determined without comparing the position information before and after irradiation with the laser light L, it is not necessary to acquire the position information before irradiation with the laser light L, and it is sufficient to acquire position information, etc., at least before irradiation of the central region R1 with the laser light L to confirm the peeling state.

[0135] In the above embodiment, the laser absorbing layer P, the device layer D2, and the surface film F2 are stacked in this order on the surface W2a of the second wafer W2, and the interface between the laser absorbing layer P and the second wafer W2 is set as the separation plane between the first wafer W1 and the second wafer W2. However, the position of the separation plane is not limited to this. Specifically, for example, a release-promoting film (not shown) for promoting separation between the first wafer W1 and the second wafer W2 may be formed between the second wafer W2 and the laser absorbing layer P on the surface W2a side of the second wafer W2, and the interface between the release-promoting film and the second wafer W2 may be set as the separation plane. In this case, it is desirable to select a material for the release-promoting film such that the adhesion strength between the release-promoting film and the second wafer W2 (silicon, etc.) is at least smaller than the adhesion strength between the release-promoting film and the laser absorbing layer P (oxide film).

[0136] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive, and the above-described embodiments may be omitted, substituted, or modified in various ways without departing from the scope and spirit of the appended claims.

[0137] REFERENCE SIGNS LIST 1 wafer processing system 31 laser irradiation device 40 control device 100 chuck 104 rotation mechanism 105 drive mechanism 108 contact sensor 110 laser irradiation unit 120 imaging mechanism L laser light T overlapped wafer W1 first wafer W2 second wafer

Claims

1. A substrate processing system for processing a substrate, comprising: a substrate holder having a holding surface for holding the substrate; a drive mechanism for moving the substrate holder in a horizontal direction; A rotation mechanism that rotates the substrate holder; a laser irradiation unit that irradiates the substrate held on the holding surface with a laser beam to form a separation surface that serves as a starting point for separation of the substrate; a detection mechanism for detecting separation of the substrate held by the substrate holder, the separation surface being used as a base point.

2. The detection mechanism includes: an acquisition unit that acquires position information of at least an upper substrate above the separation surface of the substrate; The substrate processing system according to claim 1 , further comprising: a determination unit that determines separation of the upper substrate based on the position information acquired by the acquisition unit.

3. The detection mechanism includes: acquiring position information of the upper substrate before and after the irradiation of the laser light, and detecting a horizontal deviation amount of a center of the upper substrate with respect to a center of the substrate holding part before and after the irradiation of the laser light; 3. The substrate processing system according to claim 2, wherein separation of the upper substrate is determined based on a difference value between the amount of deviation before the irradiation of the laser light and the amount of deviation after the irradiation of the laser light.

4. The detection mechanism includes: acquiring position information of the lower substrate and the upper substrate below the separation surface of the substrate before and after the irradiation with the laser light, and detecting a horizontal displacement amount of the upper substrate relative to the lower substrate before and after the irradiation with the laser light; 3. The substrate processing system according to claim 2, wherein separation of the upper substrate is determined based on a difference value between the amount of deviation before the irradiation of the laser light and the amount of deviation after the irradiation of the laser light.

5. The detection mechanism includes: acquiring position information of the lower substrate and the upper substrate below the separation surface of the substrate after the irradiation of the laser light, and detecting a horizontal displacement amount of the upper substrate relative to the lower substrate; The substrate processing system according to claim 2 , further comprising: determining whether or not to separate the upper substrate based on the amount of deviation.

6. 3. The substrate processing system of claim 2, wherein the detection mechanism acquires height-wise position information of the upper substrate and determines separation of the upper substrate based on an amount of change in the height position of the upper substrate before and after irradiation with the laser light, or a difference value between a preset reference horizontal plane and the acquired height-wise position information of the upper substrate.

7. The detection mechanism includes: A plurality of contact sensors arranged around the periphery of the substrate on the holding surface; a determination unit that determines separation of the substrate based on information detected by the contact sensor, The determination unit is 2. The substrate processing system according to claim 1, wherein separation of the upper substrate is determined by detecting contact between the contact sensor and an upper substrate above the separation surface of the substrate.

8. the detection mechanism has a spectroscopic interferometer that detects a first height position and a second height position that are different in a thickness direction of the substrate, The spectroscopic interferometer comprises: a head that irradiates a measurement light toward the substrate and detects interference between the reflected light from the first height position and the reflected light from the second height position; 2. The substrate processing system according to claim 1, further comprising: an analyzing unit that measures a distance between the first height position and the second height position based on interference of the reflected light.

9. The substrate holder includes: a plurality of lift pins that support the substrate held on the holding surface from below and lift and lower the substrate; 2. The substrate processing system according to claim 1, further comprising: a plurality of substrate drop prevention pins arranged around the periphery of the substrate held on the holding surface and configured to be liftable and lowerable integrally with the lift pins.

10. a substrate transport mechanism for transporting the substrate; the substrate transport mechanism includes a plurality of transport arms; At least one of the plurality of transport arms has a plurality of guide pins arranged around the periphery of the substrate, The substrate transport mechanism includes:

2. The substrate processing system according to claim 1, wherein the substrate after irradiation with the laser light is held and transported by the transport arm having the guide pin and transported from the laser irradiation unit to a separation unit that separates the substrate using the separation surface as a base point.

11. The drive mechanism includes: a transfer position for transferring the substrate to the substrate holder; a processing position where the separation surface is formed by irradiating the laser light, and the substrate holding part is configured to be movable between the processing position and the separation surface; A control mechanism that controls at least the operation of the drive mechanism includes: The acceleration during the movement of the substrate holder from the processing position to the transfer position after the irradiation of the laser light is The substrate processing system according to claim 1 , wherein control is executed to increase the acceleration when the substrate holder moves from the transfer position to the processing position compared to before the irradiation with the laser light.

12. a separation unit that separates the substrate using the separation surface as a base point; a substrate transport mechanism for transporting the substrate; a control mechanism; The control mechanism includes: When the detection mechanism detects separation of the substrate from the separation surface as a base point, the substrate is transported to the separation unit using the substrate transport mechanism; 12. The substrate processing system according to claim 1, further comprising a control for setting a transport speed of the substrate when transported to the separation section to a speed lower than a specified speed.

13. a substrate transport mechanism for transporting the substrate; a transfer pad that adsorbs and holds the substrate held by the substrate holder from above; a control mechanism; The control mechanism includes: When the separation of the substrate from the separation surface is detected by the detection mechanism, a control for adsorbing and holding an upper substrate above the separation surface of the substrate by the transport pad and retracting the upper substrate from a lower substrate below the separation surface of the substrate; Controlling the transport of the lower substrate held by the substrate holding unit by the substrate transport mechanism; The substrate processing system according to any one of claims 1 to 11, further comprising: a control for transferring the upper substrate held by suction by the transport pad to the substrate transport mechanism, and then transporting the upper substrate.

14. a separation unit that separates the substrate using the separation surface as a base point; a substrate transport mechanism for transporting the substrate; a control mechanism; The control mechanism includes: A substrate processing system according to any one of claims 1 to 11, wherein when separation of the substrate based on the separation surface is not detected by the detection mechanism, control is performed to transport the substrate after the formation of the separation surface to the separation section using the substrate transport mechanism.

15. A substrate processing method for processing a substrate, comprising the steps of: providing the substrate on a holding surface of a substrate holder; irradiating the substrate held on the holding surface with a laser beam to form a separation surface that serves as a starting point for separation of the substrate; detecting separation of the substrate held by the substrate holding section, the separation surface being used as a base point.

16. The detection of separation of the substrate includes: acquiring position information of at least an upper substrate above the separation surface of the substrate; The substrate processing method according to claim 15 , further comprising: determining separation of the upper substrate based on the acquired position information.

17. When detecting separation of the substrate, acquiring position information of the upper substrate before and after the irradiation of the laser light, and detecting a horizontal deviation amount of a center of the upper substrate with respect to a center of the substrate holding part before and after the irradiation of the laser light; 17. The substrate processing method according to claim 16, further comprising: determining separation of the upper substrate based on a difference value between the amount of deviation before the irradiation of the laser light and the amount of deviation after the irradiation of the laser light.

18. When detecting separation of the substrate, acquiring position information of the lower substrate and the upper substrate below the separation surface of the substrate before and after the irradiation with the laser light, and detecting a horizontal displacement amount of the upper substrate relative to the lower substrate before and after the irradiation with the laser light; 17. The substrate processing method according to claim 16, further comprising: determining separation of the upper substrate based on a difference value between the amount of deviation before the irradiation of the laser light and the amount of deviation after the irradiation of the laser light.

19. When detecting separation of the substrate, acquiring position information of the lower substrate and the upper substrate below the separation surface of the substrate after the irradiation of the laser light, and detecting a horizontal displacement amount of the upper substrate relative to the lower substrate; The substrate processing method according to claim 16 , further comprising: determining separation of the upper substrate based on the amount of misalignment.

20. When detecting separation of the substrate, 17. The substrate processing method of claim 16, further comprising acquiring height-direction position information of the upper substrate, and determining separation of the upper substrate based on an amount of change in the height position of the upper substrate before and after irradiation with the laser light, or a difference value between a preset reference horizontal plane and the acquired height-direction position information of the upper substrate.

21. Detecting the separation of the substrate; The substrate processing method according to claim 15 , wherein the determination is made by detecting contact between a plurality of contact sensors arranged around the periphery of the substrate on the holding surface and an upper substrate above the separation surface of the substrate.

22. Detecting the separation of the substrate; The substrate processing method according to claim 15 , wherein the determination is made by detecting a first height position and a second height position which are different in a thickness direction of the substrate.

23. a laser irradiation apparatus for irradiating the substrate with the laser light, The substrate holder includes: a transfer position for transferring the substrate to the substrate holder; a processing position where the separation surface is formed by irradiating the laser light, The acceleration during the movement of the substrate holder from the processing position to the transfer position after the irradiation of the laser light is The substrate processing method according to claim 15 , wherein the acceleration is set to be larger than the acceleration during movement of the substrate holder from the transfer position to the processing position before the irradiation with the laser light.