Substrate processing system and substrate processing method

Abstract

A substrate processing system for processing a substrate is provided with: a substrate holding unit having a holding surface for holding the substrate; a drive mechanism that moves the substrate holding unit in the horizontal direction; a rotation mechanism that rotates the substrate holding unit; a laser irradiation unit that irradiates the substrate held on the holding surface with a laser beam to form a separation surface that is a base point for separation of the substrate; and a detection mechanism for detecting the separation of the substrate held by the substrate holding unit with the separation surface as a base point.

Description

Technical Field

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

[0002] Patent document 1 discloses that, in a semiconductor substrate having a peeling oxide film and a semiconductor element formed on the surface, a semiconductor element is transferred to a transfer target substrate. The method described in Patent document 1 includes the following steps: locally heating the peeling oxide film by irradiating light from the back side of the semiconductor substrate; and transferring the semiconductor element to the transfer target substrate by causing peeling in the peeling oxide film and / or at the interface between the peeling oxide film and the semiconductor substrate.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2007-220749 Summary of the invention

[0006] Problem that the invention aims to solve

[0007] The technology according to the present disclosure appropriately detects whether the substrate has been separated after irradiation with the laser beam and before separation of the substrate when the substrate is separated with the separation plane formed by irradiation with the laser beam as a base point.

[0008] Solutions for solving problems

[0009] One embodiment of the present disclosure is a substrate processing system for processing a substrate, the substrate processing system comprising: a substrate holding portion having a holding surface for holding the substrate; a driving mechanism for moving the substrate holding portion in a horizontal direction; a rotating mechanism for rotating the substrate holding portion; a laser irradiation portion for irradiating a laser beam to the substrate held on the holding surface to form a separation surface as a base point for separation of the substrate; and a detection mechanism for detecting separation of the substrate held on the substrate holding portion with the separation surface as a base point.

[0010] Effects of the Invention

[0011] According to the present disclosure, when a substrate is separated with a separation plane formed by laser beam irradiation as a base point, it is possible to appropriately detect whether the substrate has been separated after the laser beam irradiation and before the substrate is separated. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a side view schematically showing the structure of a superimposed wafer to be processed.

[0013] Figure 2 FIG. 1 is a plan view schematically showing an outline of the structure of a wafer processing system.

[0014] Figure 3 It is a perspective view schematically showing the outline of the structure of the wafer transfer device.

[0015] Figure 4 It is a side view showing an outline of the structure of the laser irradiation device.

[0016] Figure 5 It is a plan view schematically showing the structure of the laser irradiation device.

[0017] Figure 6 It is an explanatory diagram showing a state of eccentricity between a first wafer and a second wafer.

[0018] Figure 7 It is a side view showing the operation of the separation device.

[0019] Figure 8 It is an explanatory diagram showing a state where a laser beam is irradiated onto a laser absorption layer.

[0020] Fig. 9 : is a flowchart showing the main steps of wafer processing.

[0021] Fig.10 It is an explanatory diagram showing an irradiation example of irradiating the laser absorption layer with a laser beam.

[0022] Fig.11 This is an explanatory diagram of the non-irradiated region generated in the laser absorption layer.

[0023] Fig.12 It is an explanatory diagram showing an irradiation example of irradiating a non-irradiated area with a laser beam.

[0024] Fig.13 It is an explanatory diagram showing another irradiation example of irradiating a non-irradiated area with a laser beam.

[0025] Fig.14 It is an explanatory diagram showing another irradiation example of irradiating a non-irradiated area with a laser beam.

[0026] Fig.15 It is an explanatory diagram showing the flow of the irradiation operation of irradiating the laser absorption layer with a laser beam.

[0027] Fig.16 It is an explanatory diagram showing a state in which wafers are transferred and overlapped between a holding plate and a transfer arm.

[0028] Fig.17 It is an explanatory diagram showing a state where overlapped wafers are carried out from a separation device.

[0029] Fig.18It is a side view showing another structural example of the laser irradiation device.

[0030] Fig.19 This is an explanatory diagram showing an example of a non-irradiated area of ​​a laser beam set on overlapping wafers.

[0031] Fig. 20 It is a plan view showing a configuration example of a laser irradiation device according to another embodiment.

[0032] Fig.21 This is an explanatory diagram that simply shows the operating principle of the spectroscopic interferometer.

[0033] Fig. 22 It is an explanatory diagram showing a state of inspecting a non-joined surface according to another embodiment. DETAILED DESCRIPTION

[0034] In the manufacturing process of semiconductor devices, in a superimposed wafer formed by bonding two semiconductor substrates (hereinafter referred to as "wafers"), a device layer formed on the surface of the second wafer is transferred to the first wafer. For example, the transfer of the device layer is performed using laser lift-off. That is, by irradiating a laser beam into the inside of the superimposed wafer to reduce the bonding force between the first wafer and the second wafer, the device layer is then transferred to the first wafer by separating the second wafer from the first wafer.

[0035] In a wafer processing system for performing the laser stripping, a laser irradiation device for irradiating the overlapping wafer with a laser beam and a separation device for separating the first wafer from the second wafer are sometimes independently configured. Here, the following situation can be imagined: after irradiating the laser beam with the laser irradiation device, the first wafer and the second wafer are accidentally separated. In this case, if the horizontal positional deviation of the first wafer and the second wafer is not detected and suppressed, the second wafer may fall from the first wafer due to the inertial force generated by the conveying action of the overlapping wafers.

[0036] The technology involved in the present disclosure is completed in view of the above situation. When the substrate is separated with the separation surface formed by irradiating the laser beam as the base point, it is appropriately detected whether the substrate has been separated after the laser beam is irradiated and before the substrate is separated. In addition, in the following description, the "separation" of the substrate as the detection object refers to the state in which the second wafer is moved in the horizontal direction relative to the first wafer. More specifically, it includes the state in which the bonding strength of the second wafer relative to the first wafer becomes zero and the second wafer can move independently relative to the first wafer, and the state in which the first wafer and the second wafer are still bonded together but the bonding strength decreases and the second wafer is offset in the horizontal direction relative to the first wafer.

[0037] 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 accompanying drawings. In addition, in this specification and the accompanying drawings, elements having substantially the same functional structure are marked with the same reference numerals to omit repeated descriptions.

[0038] In the wafer processing system 1 described later according to this embodiment, Figure 1 As shown, the overlapped wafer T as a substrate formed by bonding the first wafer W1 and the second wafer W2 is processed. Hereinafter, the surface of the first wafer W1 on the side bonded to the second wafer W2 is referred to as the surface W1a, and the surface on the side opposite to the surface W1a is referred to as the back surface W1b. Similarly, the surface of the second wafer W2 on the side bonded to the first wafer W1 is referred to as the surface W2a, and the surface on the side opposite to the surface W2a is referred to as the back surface W2b.

[0039] The first wafer W1 as the lower substrate is, for example, a semiconductor wafer such as a silicon substrate. In an embodiment, the first wafer W1 has a substantially circular plate shape. On the surface W1a of the first wafer W1, a device layer D1 and a surface film F1 are stacked in sequence from the surface W1a side. The device layer D1 includes a plurality of devices. As the surface film F1, for example, an oxide film (THOX film, SiO2 film, TEOS film), a SiC film, a SiCN film or an adhesive can be cited.

[0040] The second wafer W2 as the upper substrate is, for example, also a semiconductor wafer such as a silicon substrate. In an embodiment, the second wafer W2 has a substantially circular plate shape. On the surface W2a of the second wafer W2, a laser absorption layer P, a device layer D2, and a surface film F2 are stacked in sequence from the surface W2a side. As described later, the laser absorption layer P absorbs the laser beam irradiated from the laser irradiation unit 110. As the laser absorption layer P, for example, an oxide film (SiO2 film) is used, but as long as it is a film that absorbs the laser beam, there is no particular limitation. The device layer D2 and the surface film F2 are respectively the same as the device layer D1 and the surface film F1 of the first wafer W1. Moreover, the surface film F1 of the first wafer W1 is bonded to the surface film F2 of the second wafer W2. In addition, the position of the laser absorption layer P is not limited to the above-mentioned embodiment, and for example, it can also be formed between the device layer D2 and the surface film F2.

[0041] like Figure 2As shown, the wafer processing system 1 has a structure in which a loading and unloading block 10, a conveying block 20, and a processing block 30 are connected as one body. The loading and unloading block 10 and the processing block 30 are arranged around the conveying block 20. Specifically, the loading and unloading block 10 is arranged on the negative Y-axis direction side of the conveying block 20. The laser irradiation device 31 and the separation device 32 described later of the processing block 30 are arranged on the negative X-axis direction side of the conveying block 20, the first cleaning device 33 and the second cleaning device 34 described later are arranged on the positive X-axis direction side of the conveying block 20, and the flipping device 35 described later is arranged on the positive Y-axis direction side of the conveying block 20.

[0042] The loading and unloading block 10 can, for example, load and unload each box Ct, Cw1, Cw2 that accommodates a plurality of overlapping wafers T, a plurality of first wafers W1, and a plurality of second wafers W2 to and from the outside. A box loading table 11 is provided in the loading and unloading block 10. In the example shown in the figure, a plurality of, for example, three boxes Ct, Cw1, Cw2 can be placed in a row along the X-axis direction on the box loading table 11. In addition, the number of boxes Ct, Cw1, Cw2 placed on the box loading table 11 is not limited to the present embodiment and can be determined arbitrarily.

[0043] The conveying block 20 is provided with a wafer conveying device 22 as a substrate conveying mechanism that is configured to be movable on a conveying path 21 extending in the Y-axis direction. The wafer conveying device 22 has a plurality of, for example, three conveying arms 23a to 23c (sometimes collectively referred to as "conveying arms 23" in the following description) for holding and conveying the overlapping wafer T, the first wafer W1, or the second wafer W2. The holding surface of each conveying arm 23 has an adsorption portion 24 (see FIG. 2 ) for adsorbing and holding the overlapping wafer T, the first wafer W1, or the second wafer W2. Figure 3 ). Each transfer arm 23 is configured to be able to move freely in the horizontal direction and the vertical direction and to move freely around the horizontal axis and the vertical axis. In addition, the wafer transfer device 22 is configured to be able to transfer the overlapping wafer T, the first wafer W1, and the second wafer W2 to the boxes Ct, Cw1, and Cw2 of the box mounting table 11, the laser irradiation device 31, the separation device 32, the first cleaning device 33, the second cleaning device 34, and the flip device 35.

[0044] like Figure 3 As shown in FIG. 1 , the three transfer arms 23a to 23c are stacked in the order of the transfer arms 23a to 23c from the top. The transfer arms 23a to 23c are configured to be independently rotatable around a vertical axis.

[0045] A plurality of, for example, three, guide pins 25 are provided on the wafer holding surface of at least one of the three transport arms 23a to 23c (in the illustrated example, the transport arm 23b of the middle layer). The guide pins 25 are arranged so as to surround the overlapping wafer T when the overlapping wafer T is held by the transport arm 23b. The guide pins 25 are used to prevent the second wafer W2 from falling from the first wafer W1 as described later due to the inertial force generated by the wafer transport device 22 transporting the overlapping wafer T.

[0046] In addition, if Figure 3 As shown, at least any one of the plurality of transfer arms 23a to 23c (in the example shown in the figure, the uppermost transfer arm 23a) has a suction portion 24, i.e., a holding surface, on the lower surface side thereof for suction holding the overlapping wafer T, the first wafer W1, or the second wafer W2. Furthermore, when the second wafer W2 (upper substrate) is carried out from the separation device 32 described later, the transfer arm 23a having the suction portion 24 on the lower surface side suction holds the second wafer W2 from the upper side.

[0047] In addition, the structure of the transfer arm 23 is not limited to this embodiment, and an arbitrary structure can be adopted.

[0048] The processing block 30 includes a laser irradiation device 31, a separation device 32, a first cleaning device 33, a second cleaning device 34, and a reversing device 35. 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 reversing device 35 are not limited thereto.

[0049] The laser irradiation device 31 irradiates the interior of the overlapped wafer T, more specifically, the laser absorption layer P of the second wafer W2, with a laser beam to reduce the bonding strength at the interface between the second wafer W2 and the laser absorption layer P. In the technology disclosed in the present invention, the interface with reduced bonding strength inside the overlapped wafer T (in the present embodiment, the interface between the second wafer W2 and the laser absorption layer P) is sometimes referred to as a "separation surface".

[0050] like Figure 4 and Figure 5 As shown, 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 the wafer can be transferred between the transfer arm 23 and the holding plate 100 described later and the outer end of the overlapped wafer T can be photographed by the camera mechanism 120 described later. The processing position A2 is a position where a laser beam can be irradiated from the laser irradiation unit 110 described later to the overlapped wafer T (laser absorption layer P).

[0051] The laser irradiation device 31 has a holding plate 100 as a substrate holding portion for holding the superimposed wafer T through its upper surface. The upper surface of the holding plate 100 is provided with a wafer holding surface, and the holding plate 100 is used to adsorb and hold the entire surface of the back side W1b of the first wafer W1 or a portion of the radial inner side of the back side W1b. As an example, the holding plate 100 is an electrostatic holding plate (ESC: Electrostatic Chuck) or a vacuum holding plate (Vacuum Chuck).

[0052] In addition, the holding plate 100 is provided with lift pins 100a (see Fig.16 The lifting pin 100a is configured to penetrate a through hole formed so as to penetrate the holding plate 100 (see Fig.16 ) and can be raised and lowered freely.

[0053] The holding plate 100 is further provided with a plurality of, for example, three, wafer drop prevention pins 101 as substrate drop prevention pins so as to radially surround the overlapped wafers T on the holding surface.

[0054] When the second wafer W2 is accidentally separated from the first wafer W1 during or after the irradiation of the laser beam due to, for example, the centrifugal force generated by the rotation of the retaining plate 100 or the inertial force generated by the movement, the wafer drop prevention pin 101 suppresses the second wafer W2 from falling from the first wafer W1.

[0055] There is no particular limitation on the configuration of the wafer drop prevention pins 101. As an example, in the present embodiment, the wafer drop prevention pins 101 are configured to be rotatable together with the holding disk 100 by a rotating mechanism 104 described later, and are configured to be movable together with the holding disk 100 in the Y-axis direction by a driving mechanism 105 described later, and are configured to be able to be lifted and lowered together with the above-mentioned lifting pins 100a in the Z-axis direction.

[0056] The holding plate 100 is supported on the slider stage 103 by the air bearing 102. A rotating mechanism 104 is provided on the lower surface side of the slider stage 103. The rotating mechanism 104 has a built-in motor as a driving source. The holding plate 100 is configured to be freely rotatable around the θ axis (vertical axis) by the rotating mechanism 104 with the aid of the air bearing 102. The slider stage 103 is configured to be movable between the above-mentioned handover position A1 and the processing position A2 along a guide rail 107 provided on a base 106 and extending in the Y-axis direction by a driving mechanism 105 provided on the lower surface side thereof. In addition, there is no particular limitation on the driving source of the driving mechanism 105, and for example, a linear motor is used.

[0057] A laser irradiation unit 110 is provided above the holding disk 100 at the processing position A2. The laser irradiation unit 110 includes a laser head 111, an optical system 112, and a lens 113.

[0058] The laser head 111 has a laser oscillator (not shown) that oscillates a pulsed laser beam. The laser beam is a so-called pulsed laser. In the present embodiment, the laser beam is a CO2 laser beam, and the wavelength of the CO2 laser beam is, for example, 8.9 μm to 11 μm. In addition, the laser head 111 may also have equipment other than the laser oscillator, such as an amplifier.

[0059] The optical system 112 includes an optical element (not shown) for controlling the intensity and position of the laser beam, and an attenuator (not shown) for attenuating the laser beam to adjust the output. In addition, the optical system 112 may be configured to control the branching of the laser beam.

[0060] The lens 113 irradiates the superimposed wafer T held on the holding plate 100 with a laser beam. The laser beam emitted from the laser irradiation unit 110 passes through the second wafer W2 and irradiates the laser absorption layer P. The lens 113 may be configured to be freely movable up and down by a lifting mechanism (not shown).

[0061] In addition, a camera mechanism 120 as a detection mechanism is provided above the holding disk 100 at the handover position A1. As an example, the camera mechanism 120 includes a calculation unit 122 and one or more cameras 121 selected from a macro camera, a micro camera, etc. In addition, the camera mechanism 120 can be configured to be movable in the Y-axis direction and the Z-axis direction by a lifting mechanism (not shown) and a moving mechanism (not shown).

[0062] The camera 121 as an acquisition unit is used to photograph the outer end of the overlapped wafer T held on the holding plate 100. The camera 121 has, for example, a coaxial lens, irradiates infrared light (IR), and receives reflected light from an object. Moreover, the camera 121 acquires the position information of the overlapped wafer T (at least the second wafer W2) on the holding plate 100 by photographing the outer end of the overlapped wafer T in this way.

[0063] The calculation unit 122 as the determination unit detects the eccentricity (the offset in the horizontal direction (along the separation plane): refer to Figure 6 The details of the method for detecting the eccentricity between the first wafer W1 and the second wafer W2 using the imaging mechanism 120 will be described later.

[0064] In addition, Figure 6In order to clearly show the eccentricity between the first wafer W1 and the second wafer W2 , the holding tray 100 is illustrated without the wafer drop prevention pins 101 and the eccentricity between the first wafer W1 and the second wafer W2 is larger than the actual eccentricity.

[0065] In addition, the calculation unit 122 may be provided independently of the imaging mechanism 120 as described above, but may also be included in the control device 40 described later. In addition, the imaging result of 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 the acquisition unit and the determination unit involved in the technology of the present disclosure.

[0066] Furthermore, in the present embodiment, the "acquisition unit" of the detection mechanism involved in the technology disclosed in the present invention is a "camera 121" that at least photographs the outer end of the second wafer W2. However, as long as the position of the second wafer W2 on the holding disk 100 can be at least acquired, there is no limitation on the structure of the acquisition unit. Specifically, for example, the "acquisition unit" of the detection mechanism involved in the technology disclosed in the present invention may also be a length measuring sensor (displacement meter) that acquires the position information of the second wafer W2 by at least measuring the distance to the second wafer W2.

[0067] In addition, in the present embodiment, the case where the acquisition unit (camera 121 or length measuring sensor) involved in the technology disclosed herein is configured above the holding disk 100 at the handover position A1 is used as an example for explanation, but as long as the position of at least the second wafer W2 on the holding disk 100 can be acquired, the acquisition unit may also be configured on the side of the holding disk 100.

[0068] A transfer pad 130 is further provided above the holding plate 100 at the transfer position A1. The transfer pad 130 is configured to be freely movable up and down by a lifting mechanism (not shown). The transfer pad 130 has a suction surface on its lower surface for suction-holding the first wafer W1.

[0069] Furthermore, when the imaging mechanism 120 detects that the first wafer W1 and the second wafer W2 are eccentric in the overlapped wafer T after the laser absorption layer P is irradiated with the laser beam, the transfer pad 130 transfers the second wafer W2 between the holding plate 100 and the transfer arm 23. The details of the operation of the transfer pad 130 will be described later.

[0070] The separation device 32 separates the second wafer W2 from the first wafer W1 with the interface between the second wafer W2 and the laser absorption layer P, whose bonding strength has been reduced by the laser irradiation device 31 , as a base point, serving as a separation plane.

[0071] In one example, Figure 7As shown, the separation device 32 has an adsorption holding disk 200 for adsorbing and holding the back side W1b of the first wafer W1 from below, and an adsorption pad 210 for adsorbing and holding the back side W2b of the second wafer W2 from above. In addition, the adsorption holding disk 200 is provided with a lifting pin 200a for supporting the first wafer W1 from below so that it can be raised and lowered. The lifting pin 200a is configured to penetrate a through hole formed in a manner penetrating the adsorption holding disk 200 and can be raised and lowered freely. In the separation device 32, as shown in FIG. Figure 7 As shown, in a state where the suction pad 210 suction-holds the second wafer W2 , the suction pad 210 is lifted to separate the second wafer W2 from the laser absorption layer P.

[0072] In addition, the structure of the separation device 32 is not limited to this, and any structure can be adopted as long as it can separate the second wafer W2 from the first wafer W1.

[0073] The first cleaning device 33 cleans the surface W1a side of the first wafer W1 separated by the separation device 32. For example, a brush is brought into contact with the laser absorption layer P on the surface W1a side of the first wafer W1 to clean the laser absorption layer P. In addition, a pressurized cleaning liquid may be used to clean the first wafer W1. In addition, the first cleaning device 33 may have a structure that cleans the back side W1b of the first wafer W1 together with the surface W1a side of the first wafer W1.

[0074] The second cleaning device 34 cleans the surface W2a side of the second wafer W2 separated by the separation device 32. For example, a brush is brought into contact with the surface W2a of the second wafer W2 to clean the surface W2a. In addition, a pressurized cleaning liquid may be used to clean the second wafer W2. In addition, the second cleaning device 34 may have a structure that cleans the back side W2b of the second wafer W2 together with the surface W2a side of the second wafer W2.

[0075] In the present embodiment, the first cleaning device 33 for cleaning the first wafer W1 and the second cleaning device 34 for cleaning the second wafer W2 are independently arranged as described above. However, the first wafer W1 and the second wafer W2 may be cleaned using the same cleaning device.

[0076] The flipping device 35 flips the upper and lower surfaces of the second wafer W2 separated by the separation device 32. That is, the front and back surfaces of the separated second wafer W2 are flipped so that the surface of the second wafer W2 separated from the first wafer W1, that is, the surface W2a, faces upward. There is no particular limitation on the structure of the flipping device 35.

[0077] A control device 40 as a control mechanism is provided for the above wafer processing system 1. 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 overlapping wafers T in the wafer processing system 1. In addition, the program storage unit also stores a program for controlling the actions of the above-mentioned various processing devices, conveying devices and other drive systems to realize the wafer processing described later in the wafer processing system 1. In addition, the above-mentioned program can be recorded in a computer-readable storage medium H and installed from the storage medium H to the control device 40. In addition, the above-mentioned storage medium H can be transient or non-transient.

[0078] Next, wafer processing using the wafer processing system 1 configured as above will be described. In the present embodiment, the first wafer W1 and the second wafer W2 are bonded in advance to form a superimposed wafer T in a bonding device (not shown) outside the wafer processing system 1 .

[0079] First, the cassette Ct storing a plurality of superimposed wafers T is placed on the cassette mounting table 11 of the loading / unloading block 10 .

[0080] Next, the transfer arm 23c of the wafer transfer device 22 takes out the overlapped wafer T in the cassette Ct and transfers it to the laser irradiation device 31. In the laser irradiation device 31, as shown in FIG. Figure 8 As shown, the laser absorption layer P, more specifically, the interface between the laser absorption layer P and the second wafer W2 is irradiated with a pulsed laser beam L (CO2 laser beam) from the laser irradiation unit 110 to reduce the bonding strength between the laser absorption layer P and the second wafer W2.

[0081] A specific wafer processing method in the laser irradiation device 31 will be described.

[0082] In the laser irradiation device 31, the superimposed wafer T is transferred from the transfer arm 23c to the holding plate 100 disposed at the transfer position A1, and is sucked and held on the holding plate 100 ( Fig. 9 Step St1).

[0083] Next, the outer end portions ( ) of the overlapped wafers T (the first wafer W1 and the second wafer W2 ) held by suction on the holding plate 100 are photographed by the imaging device 120 . Fig. 9 Specifically, while rotating the holding disk 100, the camera 121 captures an image of the outer end of the overlapping wafer T in the circumferential direction of 360 degrees, thereby acquiring position information of the overlapping wafers T (the first wafer W1 and the second wafer W2) on the holding disk 100. The image pickup result of the camera 121 is output to the calculation unit 122.

[0084] In the calculation unit 122, based on the position information of the first wafer W1 and the second wafer W2 on the holding plate 100 obtained from the imaging result of the camera 121, the eccentricity of the first wafer W1 and the second wafer W2 before irradiation with the laser beam L is calculated (refer to Figure 6 ). The calculated eccentricity of the first wafer W1 and the second wafer W2 before irradiation with the laser beam L is compared with the eccentricity of the first wafer W1 and the second wafer W2 after irradiation with the laser beam L described later, thereby determining whether the first wafer W1 and the second wafer W2 are offset after irradiation with the laser beam L, that is, whether the second wafer W2 has been separated from the first wafer W1.

[0085] The calculated eccentricity amounts of the first wafer W1 and the second wafer W2 before being irradiated with the laser beam L may be output to the control device 40 .

[0086] In addition, the calculation unit 122 can calculate the eccentricity (horizontal offset) between the rotation center of the holding plate 100 and the center of the overlapping wafer T (the first wafer W1 and / or the second wafer W2) based on the imaging result of the camera 121. When it is found that the rotation center of the holding plate 100 is eccentric to the center of the overlapping wafer T, it is desirable to perform eccentricity correction control in a manner that takes into account the eccentricity calculated when the laser absorption layer P is irradiated with the laser beam L.

[0087] The calculated eccentricity between the rotation center of the holding plate 100 and the center of the overlapping wafer T (second wafer W2 ) may be output to the control device 40 .

[0088] In addition, the control device 40 acquires the central region R1 and the outer peripheral region R2 (see Fig.10 ), the central region R1 and the peripheral region R2 are set for the overlapped wafer T as the irradiation target of the laser beam L based on the imaging result of the camera 121. More specifically, regions corresponding to the central region R1 and the peripheral region R2 are set in the surface of the overlapped wafer T held on the holding plate 100 (regions overlapping the central region R1 and the peripheral region R2, respectively, when viewed from above). Regarding the positions of the central region R1 and the peripheral region R2 of the holding plate 100, the positions set based on the rotation center of the holding plate 100 and output in advance to the control device 40 can be obtained.

[0089] Next, the holding disk 100 is moved to the processing position A2 by the driving mechanism 105 .

[0090] Next, the laser irradiation unit 110 starts irradiating the laser absorption layer P, more specifically, the interface between the laser absorption layer P and the second wafer W2 with the laser beam L (CO2 laser beam).

[0091] Here, in the laser irradiation device 31 according to the present embodiment, the overlapped wafer T held on the holding plate 100 is rotated by the rotation mechanism 104, and the overlapped wafer T is moved in the Y-axis direction by the driving mechanism 105 while being irradiated with the laser beam L in a pulsed state. Then, the irradiation position of the laser beam L moves from the radial outer side to the radial inner side relative to the laser absorption layer P, and as a result, as shown in FIG. Fig.10 As shown, the laser beam L is irradiated in a spiral shape when viewed from above.

[0092] At this time, when it is desired to make the interval of the irradiation laser beam L constant so that the second wafer W2 and the laser absorption layer P are evenly separated within the wafer surface, the circumferential speed of the overlapped wafer T at the irradiation position of the laser beam L slows down as the irradiation position of the laser beam L moves from the radial outside to the radial inside, more specifically, as it approaches the rotation center of the holding plate 100, and therefore it is necessary to increase the rotation speed of the overlapped wafer T. However, when the rotation speed of the overlapped wafer T is increased in this way, the second wafer W2 may be accidentally separated from the first wafer W1 during the irradiation of the laser beam L due to the centrifugal force generated by the rotation of the overlapped wafer T.

[0093] Therefore, in the present embodiment, in the outer peripheral region R2 (see FIG. 1 ) of the holding plate 100 where the circumferential speed of the stacked wafers T is relatively fast, Fig.10 ) During the irradiation of the laser beam L, the overlapped wafer T is rotated, and the central area R1 (refer to Fig.10 ) During the process of irradiating the laser beam L, the laser beam L is scanned while the overlapping wafer T is stopped from rotating.

[0094] In addition, the central region R1 of the holding disk 100 where the laser beam L is scanned is assumed to be a circular region having a desired diameter length based on the rotation center of the holding disk 100, and is set in advance before wafer processing is performed using the laser irradiation device 31 as described above. The diameter length of the central region R1 is, for example, a radial position where the relative speed of the holding disk 100 with respect to the lens 113 of the laser irradiation unit 110 reaches an upper limit, in other words, a limit position where the laser beam L does not overlap. As an example, the diameter length of the central region R1 is approximately 10 mm.

[0095] In addition, the outer peripheral region R2 for rotating the holding disk 100 when irradiating the laser beam L is set in a region radially outward of the central region R1.

[0096] When irradiating the laser absorption layer P with the laser beam L, first, the overlapped wafer T (laser absorption layer P) in the region corresponding to the outer peripheral region R2 is irradiated with the laser beam L ( Fig. 9At this time, in the laser irradiation device 31, the laser beam L is irradiated in a pulsed manner from the laser irradiation unit 110 as described above, while the holding disk 100 (overlapped wafer T) is rotated and the holding disk 100 (overlapped wafer T) is moved in the Y-axis direction, thereby Fig.10 As shown in FIG. 1 , the laser beam L is irradiated in a spiral shape from the radially outer side toward the radially inner side. Figure 8 As shown, the laser beam L is irradiated from the back surface W2b side (the side opposite to the holding surface) of the second wafer W2, and the laser beam L passes through the second wafer W2 and is absorbed by the laser absorption layer P. As a result, the bonding strength at the interface between the laser absorption layer P and the second wafer W2 decreases.

[0097] In addition, in the embodiment, "reduction in bonding strength" refers to a state in which the bonding strength is at least reduced compared to before irradiation with the laser beam L. More specifically, it refers to a bonding strength in which the second wafer W2 is not offset (separated) in the horizontal direction due to the centrifugal force generated by the rotation of the holding plate 100 and the inertial force generated by the movement, and the second wafer W2 can be properly separated from the first wafer W1 in the separation device 32 described later.

[0098] When the irradiation of the laser beam L to the area corresponding to the outer peripheral area R2 (reduction of the bonding strength between the second wafer W2 and the laser absorption layer P) is completed, the overlapping wafer T (laser absorption layer P) in the area corresponding to the central area R1 is then irradiated with the laser beam L ( Fig. 9 When the laser beam L is irradiated to the area corresponding to the central area R1, the rotation of the holding disk 100 is stopped. Then, while the laser beam L is irradiated in a pulsed manner from the laser irradiation unit 110, the scanning of the irradiation position of the laser beam L in the X-axis direction and the movement of the holding disk 100 (overlapping wafer T) in the Y-axis direction by the driving mechanism 105 are repeatedly performed alternately (refer to Fig.10 ).

[0099] Furthermore, in order to improve the productivity of wafer processing, the laser beam L may be branched by the optical system 112 so that a plurality of points of the laser absorption layer P are irradiated with the laser beam L simultaneously.

[0100] In addition, Fig.10 In the example shown, when the region corresponding to the central region R1 is irradiated with the laser beam L, scanning of the irradiation position in the X-axis direction and movement in the Y-axis direction are repeatedly performed alternately, but the region corresponding to the peripheral region R2 may be irradiated with the laser beam L in a spiral shape as well. Alternatively, the laser beam L may be irradiated in a ring shape concentric with the overlapped wafer T (light absorbing layer P), but this is omitted in the figure.

[0101] Here, when the laser beam L is irradiated spirally to the laser absorption layer P in the outer peripheral region R2 as described above, Fig.11 As shown, near the boundary between the outer peripheral region R2 and the central region R1, a non-irradiated region of the laser beam L is generated for at most one circle in the circumferential direction. Moreover, when the non-irradiated region of the laser beam L is generated in the surface of the laser absorption layer P as described above, the laser absorption layer P may not be properly separated from the second wafer W2 in the separation device 32 at the portion corresponding to the non-irradiated region.

[0102] Therefore, in the laser irradiation device 31 according to the present embodiment, before switching the irradiation of the laser beam L from the outer peripheral area R2 to the central area R1, in other words, before stopping the rotation of the holding disk 100 in order to irradiate the central area R1 with the laser beam L, Fig.12 As shown, the laser absorption layer P is irradiated with the laser beam L concentrically so as to surround the periphery of the central region R1.

[0103] More specifically, when the peripheral region R2 is irradiated with the laser beam L, the laser beam L is irradiated spirally by rotating the holding disk 100 (overlapping wafer T) and moving it in the Y-axis direction as described above, but near the boundary between the peripheral region R2 and the central region R1, the laser absorption layer P is irradiated concentrically with the laser beam L by continuing to rotate the holding disk 100 (overlapping wafer T) and stopping moving in the Y-axis direction.

[0104] In addition, the concentric irradiation of the laser beam L to the laser absorption layer P can be performed as follows: Fig.12 As shown, only one cycle is performed around the central region R1.

[0105] Alternatively, you can Fig.13 As shown, while the laser irradiation unit 110 irradiates the laser beam L in a pulsed manner, the rotation of the holding disk 100 (overlapping wafer T) by the rotating mechanism 104 and the movement of the holding disk 100 (overlapping wafer T) in the Y-axis direction by the driving mechanism 105 are repeatedly performed alternately, thereby performing concentric circle irradiation of the laser beam L in the radial direction multiple times.

[0106] Furthermore, as long as the laser absorption layer P and the second wafer W2 can be separated appropriately, in order to suppress the influence on the device layer caused by the overlap of the irradiation position of the laser beam L, the laser absorption layer P can also be separated appropriately. Fig.14 As shown in the figure, less than one week in the circumferential direction (in Fig.14 In the example, the concentric circular irradiation of the laser beam L is stopped at 270 degrees in the circumferential direction.

[0107] Furthermore, by irradiating the laser beam L concentrically near the boundary between the outer peripheral region R2 and the central region R1 in this way, the size of the unirradiated region generated in the laser absorption layer P can be reduced, so that the laser absorption layer P and the second wafer W2 can be separated more appropriately.

[0108] In addition, Fig.12 , Fig.13 as well as Fig.14 In order to make the diagram clear, the spiral processing part in the peripheral area R2 is shown by a dotted line, and the concentric circle processing part is shown by a single-point chain line, but in fact, the irradiation interval of the laser beam L at the spiral processing part and the concentric circle processing part is fixed.

[0109] In addition, Fig.10 In the example shown, the irradiation of the laser beam L 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) in the outer peripheral region R2 is performed once. However, in practice, in order to control the interval of irradiation with the laser beam L to be constant, the conditions related to the irradiation with the laser beam L, such as the frequency of the laser beam L, the rotation speed of the holding disk 100, and the horizontal movement speed of the holding disk 100, may be changed during the irradiation with the laser beam L to the outer peripheral region R2.

[0110] Alternatively, a plurality of regions having different conditions regarding irradiation with the laser beam L may be generated in the outer peripheral region R2.

[0111] At this time, in Fig.15 As shown in the comparative example, whenever the irradiation conditions of the laser beam L are changed, the rotation of the retaining disk 100 is stopped / restarted. In other words, when the irradiation conditions of the laser beam L are changed while the retaining disk 100 is stopped, the acceleration and deceleration involved in the rotation stop / restart requires time, and thus the time involved in the laser processing increases.

[0112] Therefore, in the laser irradiation device 31 involved in the present embodiment, it is desired to continue rotating the retaining disk 100 when changing the irradiation conditions of the laser beam L in the middle of irradiating the peripheral area R2 with the laser beam L, and only stop the irradiation of the laser beam L to the overlapping wafer T and the horizontal movement of the retaining disk 100.

[0113] By continuously rotating the holding disk 100 while changing the irradiation conditions of the laser beam L, Fig.15 As in the example of the present application shown, the time involved in the acceleration and deceleration of the rotation speed of the holding disk 100 can be reduced, thereby shortening the time involved in the laser processing.

[0114] In addition, in the case where the holding disk 100 continues to rotate and the irradiation conditions of the laser beam L are changed as described above, the irradiation restart position at which the irradiation of the laser beam L is restarted after the irradiation conditions are changed can be the same position as the irradiation end position at which the irradiation of the laser beam L was ended before the irradiation conditions were changed, or can be different positions if at least the irradiation positions of the laser beam L do not overlap.

[0115] When the irradiation restart position of the laser beam L is made the same as the irradiation end position, after the irradiation condition of the laser beam L is changed, the irradiation of the laser beam L is restarted until the irradiation end position is brought to the position directly below the irradiation of the laser beam L by the rotation of the holding plate 100. In this case, the interval of the irradiation laser beam L can be controlled to be constant over the entire surface of the laser absorption layer P, and the separation between the second wafer W2 and the laser absorption layer P can be controlled to be uniform within the wafer surface.

[0116] On the other hand, when the irradiation restart position of the laser beam L is made different from the irradiation end position, after the irradiation condition of the laser beam L is changed, the irradiation of the laser beam L is quickly restarted at a position where at least the irradiation position of the laser beam L does not overlap. In this case, the waiting time until the irradiation of the laser beam L is started can be reduced, so that the time involved in the laser processing can be further shortened.

[0117] The central region R1 and the peripheral region R2 are irradiated with the laser beam L. When the bonding strength between the second wafer W2 and the laser absorption layer P decreases over the entire surface, the holding plate 100 (overlapping wafer T) is then moved to the transfer position A1 by the driving mechanism 105 .

[0118] Next, at the transfer position A1, the imaging mechanism 120 is used to capture the outer end portion ( Fig. 9 Specifically, while rotating the holding disk 100, the camera 121 captures an image of the outer end of the overlapping wafer T at a 360-degree circumferential direction, thereby acquiring position information of the overlapping wafers T (the first wafer W1 and the second wafer W2) on the holding disk 100. The image pickup result of the camera 121 is output to the calculation unit 122.

[0119] In the calculation unit 122, based on the position information obtained from the imaging result of the camera 121, the eccentricity of the first wafer W1 and the second wafer W2 after being irradiated with the laser beam L is calculated (refer to Figure 6 The calculated eccentricity of the first wafer W1 and the second wafer W2 after being irradiated with the laser beam L may be output to the control device 40 .

[0120] In the control device 40, the difference between the eccentricity of the first wafer W1 and the second wafer W2 before being irradiated with the output laser beam L and the eccentricity of the first wafer W1 and the second wafer W2 after being irradiated with the laser beam L is calculated, and based on the difference, it is determined whether the second wafer W2 has been separated from the first wafer W1 ( Fig. 9 Step St6).

[0121] In the wafer processing system 1 according to the present embodiment, the separation device 32 provided outside the laser irradiation device 31 separates the first wafer W1 and the second wafer W2 from the overlapped wafer T in which the bonding strength between the second wafer W2 and the laser absorption layer P is reduced.

[0122] However, as described above, when the bonding strength between the second wafer W2 and the laser absorption layer P is reduced by irradiating the laser beam L, the second wafer W2 may sometimes be separated from the laser absorption layer P (first wafer W1) before being transported to the separation device 32 due to the inertial force when moving to the handover position A1 through the driving mechanism 105 and the centrifugal force generated by the rotation of the retaining disk 100.

[0123] Furthermore, if the second wafer W2 is separated before being transferred to the separation device 32 , not only may the overlapped wafer T not be properly transferred to the separation device 32 , but the second wafer W2 may also fall in the system, causing a malfunction.

[0124] In this regard, in the laser irradiation device 31 according to the present embodiment, in step St6, it is possible to determine whether the second wafer W2 has been separated from the first wafer W1 before the overlapped wafer T is transported to the separation device 32. Thus, it is suppressed that the overlapped wafer T is transported to the separation device 32 by the wafer transport device 22 in a state where the second wafer W2 is separated from the first wafer W1, thereby reducing the risk of the second wafer W2 falling within the system.

[0125] In addition, in this embodiment, if Figure 4 and Figure 5 As shown, a plurality of, at least three, wafer drop prevention pins 101 are provided to surround the overlapping wafers T held on the holding plate 100. Thus, even if the second wafer W2 is separated from the first wafer W1 after the laser absorption layer P is irradiated with the laser beam L, the second wafer W2 can be prevented from falling in the laser irradiation device 31.

[0126] For the overlapped wafer T determined to be the second wafer W2 separated from the first wafer W1 in step St6, first, the transfer pad 130 is raised while the back side W2b of the second wafer W2 is held by the transfer pad 130, so that the second wafer W2 is withdrawn from the first wafer W1 ( Fig. 9Step St7).

[0127] Next, the first wafer W1 on the holding plate 100 is transferred to the transfer arm 23c of the wafer transfer device 22, and the first wafer W1 is removed from the laser irradiation device 31 ( Fig. 9 At this time, when the eccentricity (positional deviation) of the first wafer W1 relative to the holding plate 100 is detected in step St2, the insertion position of the transfer arm 23c can be adjusted according to the eccentricity.

[0128] Next, the second wafer W2 held by the transfer pad 130 is transferred to the transfer arm 23a of the wafer transfer device 22, and the second wafer W2 is removed from the laser irradiation device 31 ( Fig. 9 Step St9). At this time, in order to suck and hold the back side W2b of the second wafer W2 (the side opposite to the side separated from the first wafer W1), it is desirable to use the transfer arm 23a that sucks and holds the second wafer W2 from above. In addition, the second wafer W2 can also be delivered to the transfer arm 23a via the holding plate 100.

[0129] After the first wafer W1 is unloaded from the laser irradiation device 31, the first wafer W1 is transported to the box Cw1 of the box mounting table 11 by the wafer transport device 22. In addition, after the upper and lower surfaces of the second wafer W2 unloaded from the laser irradiation device 31 are turned over by the turning device 35, that is, after the second wafer W2 is in a state where the surface of the side separated from the first wafer W1 faces upward, the second wafer W2 is transported to the box Cw2 of the box mounting table 11 by the wafer transport device 22. At this time, the surface W1a and the surface W2a of the first wafer W1 and the second wafer W2, which are the surfaces on the separation side, can be cleaned by the first cleaning device 33 and the second cleaning device 34, respectively, and then the first wafer W1 and the second wafer W2 are transported to the boxes Cw1 and Cw2 of the box mounting table 11, respectively.

[0130] On the other hand, the overlapped wafer T determined as the second wafer W2 not separated from the first wafer W1 in step St6 is transferred from the holding plate 100 to the transfer arm 23b of the wafer transfer device 22 and is carried out from the laser irradiation device 31 ( Fig. 9 Step St10).

[0131] Here, when the separation of the second wafer W2 is not properly detected in the above-mentioned step St6 although the second wafer W2 has actually been separated from the first wafer W1, the second wafer W2 may have fallen within the system due to the impact applied to the overlapping wafer T when it was handed over from the holding plate 100 to the conveying arm 23, the inertial force generated when it was conveyed by the conveying arm 23, etc.

[0132] In this regard, the laser irradiation device 31 according to the present embodiment is configured to be able to move up and down in the Z-axis direction integrally with the lift pins 100 a , the wafer drop prevention pins 101 arranged to surround the overlapped wafers T held on the holding plate 100 , as described above.

[0133] The overlapping wafer T is transferred from the holding disk 100 to the conveying arm 23b in the following manner: after the overlapping wafer T is supported from below and raised by the lifting pins 100a, the conveying arm 23b is inserted between the holding surface of the holding disk 100 and the lower surface of the overlapping wafer T (the back side W1b of the first wafer W1), and then the overlapping wafer T is lowered by the lifting pins 100a.

[0134] At this time, if Fig.16 As shown, by lifting and lowering the wafer drop prevention pins 101 and the lifting pins 100a integrally, even when the overlapping wafer T is raised by the lifting pins 100a, the overlapping wafer T can be surrounded by the wafer drop prevention pins 101, thereby preventing the second wafer W2 from falling when it is handed over from the holding plate 100 to the transfer arm 23b.

[0135] In the wafer processing system 1 according to the present embodiment, when transferring the overlapped wafer T irradiated with the laser beam L from the laser irradiation device 31 to the separation device 32 , the transfer arm 23 b having guide pins 25 arranged on the holding surface so as to surround the overlapped wafer T is used.

[0136] Thus, even when the second wafer W2 is separated from the first wafer W1 , it is possible to suppress the second wafer W2 from falling due to the inertial force when the superimposed wafer T is transported from the laser irradiation device 31 to the separation device 32 .

[0137] The overlapped wafer T carried out from the laser irradiation device 31 is transported to the separation device 32 by the wafer transport device 22. Figure 7 As shown, in the separation device 32, the back side W1b of the first wafer W1 is held by the adsorption holding disk 200, and the back side W2b of the second wafer W2 is held by the adsorption pad 210. Afterwards, while the adsorption pad 210 is holding the second wafer W2 by adsorption, the adsorption pad 210 is raised to separate the first wafer W1 from the second wafer W2. At this time, since the bonding strength at the interface between the laser absorption layer P and the second wafer W2 is reduced by irradiating the laser beam L as described above, the second wafer W2 can be separated without applying a large load.

[0138] like Fig.17As shown, 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 reversing device 35. Then, after being turned into a state with the surface W2a facing upward by the reversing device 35, it is transferred to the second cleaning device 34.

[0139] The second cleaning device 34 cleans the surface W2a, which is the surface separated from the first wafer W1. In addition, the back surface W2b may be cleaned together with the surface W2a in the second cleaning device 34. In addition, cleaning units for cleaning the surface W2a and the back surface W2b may be separately provided.

[0140] Thereafter, the second wafer W2 cleaned by the second cleaning device 34 is transferred to the cassette Cw2 on the cassette mounting table 11 by the wafer transfer device 22 .

[0141] On the other hand, Fig.17 As shown, the first wafer W1 held on the adsorption holding plate 200 is handed over to the transfer arm 23c and transferred to the first cleaning device 33. The transfer by the transfer arm 23c and the transfer of the second wafer W2 by the transfer arm 23a can be performed simultaneously or independently. In the first cleaning device 33, the surface on the side separated from the second wafer W2, that is, the surface W1a side, specifically, the surface of the laser absorption layer P is cleaned. In addition, in the first cleaning device 33, the back side W1b of the first wafer W1 can also be cleaned together with the surface of the laser absorption layer P. In addition, cleaning parts for cleaning the surface of the laser absorption layer P and the back side W1b of the first wafer W1 can also be separately provided. Thereafter, the first wafer W1 cleaned by the first cleaning device 33 is transferred to the box Cw1 of the box mounting table 11 by the wafer transfer device 22.

[0142] In this way, a series of wafer processing in the wafer processing system 1 is completed.

[0143] In addition, in the laser irradiation device 31 involved in the above embodiment, as described above, the separation of the second wafer W2 is detected based on the difference in the eccentricity of the second wafer W2 relative to the first wafer W1 before and after the overlapping wafer T (laser absorption layer P) is irradiated with the laser beam L. However, there is no limitation on the structure of the detection mechanism of the second wafer W2 and the detection method using the structure of the detection mechanism, and at least any one of the following structures and methods may be replaced with the above structure and method or additionally have the above structure and method.

[0144] (1) As described above, when the second wafer W2 is actually separated from the first wafer W1 but no decentering (horizontal deviation) occurs after the overlapping wafer T (laser absorption layer P) is irradiated with the laser beam L, the separation of the second wafer W2 cannot be properly detected.

[0145] Therefore, a load may be applied to the overlapped wafer T during the period when the holding plate 100 is moved from the processing position A2 to the delivery position A1 after the overlapped wafer T is irradiated with the laser beam L by the laser irradiation device 31, thereby displacing the second wafer W2 relative to the first wafer W1 (moving the second wafer W2 in the horizontal direction). More specifically, for example, the acceleration during the period when the holding plate 100 is moved from the processing position A2 to the delivery position A1 after the laser beam L is irradiated may be greater than the acceleration during the period when the holding plate 100 is moved from the delivery position A1 to the processing position A2 before the laser beam L is irradiated, so that the inertial force as a load may be applied to the overlapped wafer T.

[0146] At this time, the magnitude of the load applied to the overlapping wafer T after irradiation with the laser beam L is controlled to a magnitude that can cause the separated second wafer W2 to shift on the first wafer W1, and to a magnitude that does not cause the second wafer W2 to shift on the first wafer W1 (the second wafer W2 is not separated) when the second wafer W2 is not separated.

[0147] According to the above method (1), the first wafer W1 and the second wafer W2 are intentionally eccentric (shifted in the horizontal direction) by intentionally applying a load to the overlapping wafers T after being irradiated with the laser beam L. This can avoid the state in which the second wafer W2 is separated from the first wafer W1 but is not eccentric, as described above, and as a result, the risk of the second wafer W2 falling from the first wafer W1 in the system can be more appropriately suppressed.

[0148] Furthermore, according to the above method (1), by intentionally eccentricating the first wafer W1 and the second wafer W2 in this way, the tact time associated with the processing in the laser irradiation device 31 can be reduced.

[0149] Specifically, according to the above method (1), by intentionally eccentricating the first wafer W1 and the second wafer W2, the eccentricity can be detected by only performing regional imaging of at least a portion of the outer end, for example, only one portion in the circumferential direction, without imaging the outer end of the overlapping wafer T in the circumferential direction of 360 degrees. Therefore, at least the time required for imaging the outer end after irradiating the overlapping wafer T (laser absorption layer P) with the laser beam L can be omitted, thereby reducing the production cycle.

[0150] (2) In the laser irradiation device 31, as Fig.18 As shown, it is also possible to replace 4 and Figure 5The wafer drop prevention pin 101 shown, or a plurality of, for example, three, contact sensors 108 as a detection unit and a calculation unit 109 as a determination unit are additionally configured on the basis of the wafer drop prevention pin 101, wherein the plurality of, for example, three, contact sensors 108 as a detection unit are configured in a manner surrounding the overlapping wafers T on the holding surface of the holding plate 100, and the calculation unit 109 as a determination unit is used to determine the separation of the second wafer W2 through the contact sensors 108. In this case, these contact sensors 108 and the calculation unit 109 constitute the detection mechanism involved in the technology of the present disclosure as a substitute for or in addition to the imaging mechanism 120 involved in the above-mentioned embodiment.

[0151] In addition, the calculation unit 109 may be included in the control device 40 or may be independently provided in the laser irradiation device 31 .

[0152] According to the above configuration (2), the separation of the second wafer W2 can be detected only by determining whether the contact sensor 108 is in contact with the second wafer W2, without photographing the outer end of the overlapped wafer T (laser absorption layer P) after irradiating the overlapped wafer T (laser absorption layer P) with the laser beam L. Therefore, the photographing of the outer end by the imaging mechanism 120 after irradiating the overlapped wafer T (laser absorption layer P) with the laser beam L can be omitted, thereby reducing the production tact associated with the processing in the laser irradiation device 31.

[0153] In addition, in the wafer processing system 1 involved in the technology disclosed in the present invention, both the imaging mechanism 120 and the contact sensor 108 as detection mechanisms can be configured in the laser irradiation device 31. In this case, the following two processes can be performed: the imaging mechanism 120 detects the separation of the first wafer W1 and the second wafer W2; and the contact sensor 108 detects the separation of the first wafer W1 and the second wafer W2.

[0154] In this case, when the contact between the touch sensor 108 and the second wafer W2 is detected, the detection of separation of the first wafer W1 and the second wafer W2 by the imaging mechanism 120 (imaging the outer end of the overlapping wafer T) can be omitted.

[0155] (3) In the above embodiment, the separation of the second wafer W2 is detected based on the difference in the eccentricity of the first wafer W1 and the second wafer W2 before and after irradiation with the laser beam L, which is obtained by photographing the outer ends of the overlapping wafers T (the first wafer W1 and the second wafer W2) by the imaging mechanism 120.

[0156] However, it is not necessary to image the outer edge of the overlapped wafer T (the first wafer W1 and the second wafer W2 ) by the imaging mechanism 120 before and after the irradiation of the laser beam L. The imaging mechanism 120 may be performed only after the irradiation of the laser beam L.

[0157] According to the above method (3), as long as the outer ends of the overlapping wafers T (the first wafer W1 and the second wafer W2) can be photographed at least after irradiating the laser beam L to obtain the eccentricity (position offset in the horizontal direction) of the first wafer W1 and the second wafer W2, the separation of the second wafer W2 can be determined based on the eccentricity.

[0158] (4) In the above embodiment, the separation of the second wafer W2 is detected based on the difference in the eccentricity of the first wafer W1 and the second wafer W2 before and after irradiation with the laser beam L, which is obtained by photographing the outer ends of the overlapping wafers T (the first wafer W1 and the second wafer W2) by the imaging mechanism 120.

[0159] However, due to reasons such as the viewing angle and imaging magnification of the imaging mechanism 120 , the imaging mechanism 120 may not be able to capture an image of the outer end of the first wafer W1 , which is the lower substrate, on the holding plate 100 .

[0160] Therefore, in the wafer processing system 1 according to the technology of the present disclosure, only the outer end portion of the second wafer W2 serving as the upper substrate can be imaged by the imaging mechanism 120 .

[0161] In this case, the position information of the second wafer W2 on the holding plate 100 before and after the irradiation of the laser beam L is acquired based on the imaging result of the imaging mechanism 120, and the eccentricity (offset) in the horizontal direction of the center (more specifically, the rotation center) of the second wafer W2 relative to the center of the holding plate 100 before and after the irradiation of the laser beam L is detected. Furthermore, by calculating the difference between the eccentricity of the center of the second wafer W2 relative to the center of the holding plate 100 before the irradiation of the laser beam and the eccentricity of the center of the second wafer W2 relative to the center of the holding plate 100 after the irradiation of the laser beam, the separation of the second wafer W2 can be determined based on the difference.

[0162] According to the above method (4), even when the outer ends of the overlapping wafers T (the first wafer W1 and the second wafer W2) cannot be properly photographed by the imaging mechanism 120, separation of the second wafer W2 can be detected by acquiring at least the position information of the second wafer W2.

[0163] (5) In the above embodiment, the imaging mechanism 120 images the outer ends of the overlapping wafers T (the first wafer W1 and the second wafer W2) at 360 degrees in the circumferential direction to calculate the eccentricity between the first wafer W1 and the second wafer W2 and detect the separation of the second wafer W2.

[0164] However, the shooting of the outer ends of the overlapping wafers T (the first wafer W1 and the second wafer W2) using the camera mechanism 120 does not necessarily have to be performed 360 degrees in the circumferential direction. The separation of the second wafer W2 can also be detected by shooting at least two circumferential positions of the overlapping wafer T (for example, a position of 0 degrees from the circumferential reference position and a position 90 degrees from the circumferential reference position).

[0165] According to the above method (5), the separation of the second wafer W2 can be detected by regionally photographing the outer end of the overlapped wafer T at two locations in the circumferential direction, without photographing the outer end of the overlapped wafer T at 360 degrees in the circumferential direction. Therefore, the photographing time of the outer end by the photographing mechanism 120 after irradiation with the laser beam L can be shortened, thereby reducing the production tact related to the processing in the laser irradiation device 31.

[0166] (6) In the above embodiment, the laser irradiation unit 110 irradiates the central region R1 and the outer peripheral region R2 with the laser beam L to reduce the bonding strength over the entire surface of the second wafer W2 and the laser absorption layer P.

[0167] However, when the bonding strength between the second wafer W2 and the laser absorption layer P is reduced over the entire surface, there is a risk that the second wafer W2 may fall due to the inertial force when the superimposed wafer T is transported as described above.

[0168] Therefore, in the wafer processing system 1 involved in the technology disclosed in the present invention, it can be set to stop irradiating the laser beam L in at least a portion of the interface between the second wafer W2 and the laser absorption layer P, and maintain the bonding strength between the second wafer W2 and the laser absorption layer P in the at least a portion of the interface not irradiated with the laser beam L.

[0169] More specifically, in the wafer processing system 1, as Fig.19 As shown, the outermost peripheral region R0 (see FIG. 1 ) which is set at the outermost peripheral position of the outer peripheral region R2 in the interface between the second wafer W2 and the laser absorption layer P can be Fig.19 (a)) of the central region R3 (see Fig.19 (b)) forms a region that does not reduce the bonding strength between the second wafer W2 and the laser absorption layer P.

[0170] According to the above method (6), by forming an area in which the bonding strength is not reduced (laser beam L is not irradiated) in at least a portion 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, thereby preventing the second wafer W2 from falling due to the inertial force acting on the overlapping wafer T.

[0171] In the wafer processing system 1 involved in the technology disclosed herein, by using the above-mentioned embodiment or at least any one of the above-mentioned methods (1) to (6), the risk of the second wafer W2 falling from the first wafer W1 in the system can be suppressed by detecting the separation of the second wafer W2 before the overlapping wafer T is moved out of the laser irradiation device 31.

[0172] In addition, when at least any one of the above methods (1) to (6) is executed in this way, regarding the "acquisition unit" of the detection mechanism, a length measuring sensor (displacement meter) can be used instead of the camera 121 as described above.

[0173] In addition, in the above embodiment, when Fig. 9 As shown, when the separation of the second wafer W2 is detected in step St6 , the first wafer W1 and the second wafer W2 are sequentially unloaded from the laser irradiation device 31 (steps St8 and St9 ), but the operation when the separation is detected is not limited to this.

[0174] For example, the first wafer W1 and the second wafer W2 may be moved out of the laser irradiation device 31 as a whole using the transfer arm 23b having the guide pins 25 as in step St10, instead of moving the first wafer W1 and the second wafer W2 out of the laser irradiation device 31 separately as described above. In this case, in order to suppress the second wafer W2 from falling off the first wafer W1, it is desirable to control the lifting speed of the overlapping wafer T by the lifting pins 100a and the conveying speed of the overlapping wafer T by the wafer conveying device 22 to be lower than the normal moving speed (when the separation of the second wafer W2 is not detected by step St6), that is, the specified speed.

[0175] In addition, for example, when the 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 transport the overlapping wafer T by the wafer transport device 22, an alarm can be issued by the control device 40 and subsequent processing can be stopped. In addition, in this case, the overlapping wafer T can be removed from the laser irradiation device 31 by manual recovery by the operator.

[0176] Furthermore, in the above-mentioned embodiment, the wafer processing method of the present disclosure is applied when performing laser stripping to separate the second wafer W2 from the laser absorption layer P. However, the technology involved in the present disclosure can be arbitrarily applied as long as at least a portion of the first wafer W1 and / or the second wafer W2 is separated from the overlapping wafer T in which the first wafer W1 and the second wafer W2 are bonded.

[0177] For example, in the manufacturing process of semiconductor devices, a laser beam is irradiated along the surface direction inside a silicon substrate of a wafer having a plurality of electronic circuits and other devices formed on the surface to form a modified layer, and the wafer is separated using the modified layer as a separation surface, thereby thinning the wafer. The laser beam uses a YAG laser beam. When forming a modified layer as a separation surface that serves as a base point for wafer thinning in this way, the disclosed technology can also be applied.

[0178] Furthermore, the technology according to the present disclosure can also be applied to a debonder technology for separating the first wafer W1 and the second wafer W2 in the superimposed wafer T in which the first wafer W1 and the second wafer W2 are bonded.

[0179] In addition, when a laser beam is irradiated into the interior of the silicon substrate to form a modified layer and the wafers are separated based on the modified layer as described above, in the laser irradiation device 31, the position offset between the lower wafer retained and held on the holding disk 100 and the upper wafer to be removed by separation can be detected instead of detecting the horizontal position offset of the first wafer W1 and the second wafer W2 shown in the above embodiment.

[0180] Specifically, for example, a spectroscopic interferometer can be configured in the laser irradiation device 31 to replace the camera mechanism 120 and the length measuring sensor, 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) can be detected in the thickness direction of the overlapping wafer T (position information in the height direction of the overlapping wafer T) to determine whether the second wafer W2 has been separated from the first wafer W1.

[0181] like Fig. 20 As shown in FIG. 1 , a laser irradiation device 310 according to another embodiment is provided with a spectroscopic interferometer 320 . The spectroscopic interferometer 320 includes a head 321 and an analysis unit 322 .

[0182] The head 321 includes: an irradiation unit (not shown) for irradiating the overlapping wafers T on the holding plate 100 with measuring light; and a spectroscopic unit (not shown) for receiving the overlapping wafers T at different height positions (a first height position H1 and a second height position H2: refer to Fig.21 and Fig. 22 ) and detects interference between the reflected lights. As the measurement light irradiated from the irradiation unit, light having transmissivity with respect to the second wafer W (silicon) can be arbitrarily selected.

[0183] The analysis unit 322 calculates the distance between the first height position H1 and the second height position H2 by detecting interference between reflected lights at each of the first height position H1 and the second height position H2 detected by the head 321. In addition, the analysis unit 322 may be incorporated into the control device 40.

[0184] Next, a method of determining whether the second wafer W2 has been separated from the first wafer W1 using the spectroscopic interferometer 320 will be described.

[0185] In the same manner as in the above embodiment, the laser beam L is irradiated to the central region R1 and the peripheral region R2 by the driving mechanism 105 to move the superimposed wafer T whose bonding strength is reduced over the entire surface of the second wafer W2 and the laser absorption layer P to the lower side of the spectroscopic interferometer 320. Next, while rotating the holding plate 100, Fig.21 As shown, the measurement light L2 from the irradiation unit of the head 321 is irradiated toward the overlapped wafer T, and the reflected light from the overlapped wafer T is caused to enter the spectroscopic unit. In the spectroscopic unit, when interference (reflection spectrum) of the reflected light is detected on the entire surface of the overlapped wafer T, it is determined that the second wafer W2 has been separated from the first wafer W1.

[0186] However, as in the above embodiment, when the holding tray 100 holding the superimposed wafer T with reduced bonding strength over the entire surface of the second wafer W2 and the laser absorption layer P is moved and rotated, the second wafer W2 may fall off the first wafer W1 .

[0187] In view of this point, when the holding disk 100 holding the overlapped wafer T whose bonding strength is reduced on the entire surface of the second wafer W2 and the laser absorption layer P is moved or rotated, it is desirable to reduce the moving speed and the rotating speed. Alternatively, the spectroscopic interferometer 320 may be relatively moved or rotated above the holding disk 100 (overlapped wafer T) instead of moving or rotating the holding disk 100. In addition, for example, by configuring the spectroscopic interferometer 320 and the laser irradiation device 310 side by side or integrally, the bonding strength reduction process using the laser irradiation device 310 and the determination of separation using the spectroscopic interferometer 320 may be performed simultaneously or continuously.

[0188] A more specific determination method of determining whether the second wafer W2 and the first wafer W1 are separated by the spectroscopic interferometer 320 will be described.

[0189] When the bonding strength is reduced at the interface between the second wafer W2 and the laser absorption layer P by the laser irradiation beam L and the second wafer W2 is separated from the first wafer W1, it is conceivable that Fig.21 and Fig. 22As shown, a gap or space S between the second wafer W2 and the first wafer W1 is formed on a separation surface between the second wafer W2 and the first wafer W1 (in the example shown in the figure, an interface between the second wafer W2 and the laser absorption layer P).

[0190] When the space S is generated at the interface between the second wafer W2 and the laser absorption layer P, the measurement light L2 is reflected at different first height positions H1 and second height positions H2, such as the upper surface and the lower surface of the space. Fig.21 As shown, the reflected lights L2a and L2b from each height position enter the spectroscopic unit.

[0191] In the spectroscopic unit, when the interference (reflection spectrum) of the reflected lights L2a and L2b is detected, the thickness t of the space S (the distance between the first height position H1 and the second height position H2) is calculated based on the detection result by the analysis unit 322. The calculated thickness t of the space S is output to the control device 40.

[0192] In the control device 40, it is possible to determine whether a space S is formed at the interface between the second wafer W2 and the laser absorption layer P based on the output thickness t. Furthermore, when it is determined that the space S is formed on the entire surface of the overlapping wafer T (laser absorption layer P), the second wafer W2 and the laser absorption layer P are completely peeled off, and thus it can be determined that the second wafer W2 has been separated from the first wafer W1.

[0193] In one example, it is possible to determine whether a space S is generated at the interface (separation surface) between the second wafer W2 and the laser absorption layer P by comparing the measurement result (thickness t) of the spectroscopic interferometer 320 after the overlapping wafer T is irradiated with the laser beam L with a pre-set first threshold. When the measurement result exceeds the pre-set first threshold, it is determined that the space S is formed. The first threshold used for comparison may be, for example, a value obtained by measuring the same overlapping wafer T before the laser beam L is irradiated by the laser irradiation device 31. That is, the first threshold may be obtained by comparing the measurement result in a state where the laser beam L is not irradiated (no space S is generated) with the measurement result in a state where the laser beam L is irradiated (space S is generated). Alternatively, the first threshold may be obtained in advance from different wafers (for example, dummy wafers, etc.). That is, for example, the measurement result of a different wafer whose bonding strength is reduced by irradiating the laser beam L may be compared with the measurement result of an actual wafer whose bonding strength is reduced by irradiating the laser beam L to obtain the first threshold.

[0194] In addition, as a value used as the first threshold, it is possible to use the calculated thickness t of the space S. In this case, the first threshold is a value determined to be formed as the space S, and is a value determined to be formed as the space S and the thickness t> 0. The first threshold for comparison may also be set to a value greater than 0.

[0195] Moreover, in the control device 40, when the area of ​​the interface exceeding the first threshold satisfies the predetermined second threshold, it is determined that the second wafer W2 is not separated from the first wafer W1 and the second wafer W2 will not fall. The second threshold is set within a range in which the second wafer W2 cannot fall from the first wafer W1 during the process of transporting the overlapping wafer T, etc. For example, the second threshold is set in advance through experiments or simulations. As a value used as the second threshold, the area ratio of the area where the space S is formed relative to the entire area of ​​the overlapping wafer T (laser absorption layer P) when viewed from above can be used.

[0196] Furthermore, in order to appropriately detect the separation of the second wafer W2 relative to the first wafer W1, it is desirable to detect the reflected light from the overlapping wafer T on the entire surface of the overlapping wafer T (laser absorption layer P) using the spectroscopic interferometer 320. However, in order to shorten the time required for inspection and improve productivity, only a portion of the irradiation interval of the laser beam L irradiated to the laser absorption layer P (for example, only a portion in the radial direction or circumferential direction) may be inspected. Alternatively, for example, in Fig.19 As shown, when a portion of the interface between the second wafer W2 and the laser absorption layer P forms an area that does not reduce the bonding strength, only the area that does not reduce the bonding strength can be inspected, and if there is no separation (if the thickness t=0), it can be determined that the first wafer W1 and the second wafer W2 are not separated.

[0197] In addition, in the above-mentioned other embodiments, the case where the spectroscopic interferometer 320 for detecting the separation between the first wafer W1 and the second wafer W2 is configured inside the laser irradiation device 310 is described as an example, but the spectroscopic interferometer 320 may also be configured outside the laser irradiation device 310. That is, in the technology involved in the present disclosure, the laser irradiation device 31 and the inspection device (not shown) having the spectroscopic interferometer 320 for detecting the separation between the first wafer W1 and the second wafer W2 may be configured independently in the wafer processing system 1.

[0198] 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 the thickness t>0), but the method of inspecting the separation state is not limited thereto.

[0199] Specifically, regarding the overlapped wafer T in which the space S is formed at the interface between the first wafer W1 and the second wafer W2 by the laser irradiation device 310, it can be considered that Fig. 22 As shown in FIG. 1 , 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 the peeling of the second wafer W2 and the laser absorption layer P. Fig. 22 In FIG. 1 , the position of the second wafer W2 before the space S is formed is indicated by a dotted line, and the position of the second wafer W2 after the space S is formed is indicated by a solid line.

[0200] Therefore, when determining whether the space S is formed in order to understand the separation state of the first wafer W1 and the second wafer W2 , the height of the overlapped wafer T can be measured.

[0201] Specifically, for example, an optical plane (reference horizontal plane) can be set in the spectroscopic interferometer 320 to detect the interference (reflection spectrum) between the reflected light from the optical plane and the reflected light from the back side W2b of the second wafer W2. In this case, the height difference between the reference horizontal plane and the overlapped wafer T before and after the space S is formed is calculated. If the difference changes before and after the space S is formed, it can be determined that the space S is formed.

[0202] Or, in Fig.19 As shown, when a portion of the interface between the second wafer W2 and the laser absorption layer P is formed so as not to reduce the bonding strength, if the region has the same height as the optical plane, it is determined that the space S is not formed.

[0203] In addition, when measuring the height of the overlapped wafer T (the height position of the back surface W2b of the second wafer W2) in this way, the change amount t2 of the height of the overlapped wafer T due to the formation of the space S (see Fig. 22 ) replaces the measurement result used for comparison with the first threshold value in the above-mentioned embodiment, that is, the thickness t of the space S, as the measurement result used for comparison with the first threshold value.

[0204] Furthermore, for example, a displacement meter (not shown) may be provided above the holding plate 100 in place of the spectroscopic interferometer 320 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, for example, the distance to the back surface W2b of the second wafer W2 before and after the space S is formed may be detected, and the distance to the back surface W2b in the area where the space S is formed may be detected compared with the distance to the back surface W2b in the area where the bonding strength is not reduced (see Fig.19 ) to the back side W2b, etc., to determine the separation of the first wafer W1 and the second wafer W2. Fig. 20In the structure of the laser irradiation device 310 shown, the device can be configured simply by replacing the spectroscopic interferometer 320 with a displacement meter (length measurement sensor) not shown.

[0205] In the above-mentioned laser irradiation device, the central region R1 and the outer peripheral region R2 (see Fig.10 ) are sequentially irradiated with the laser beam L. However, for example, it is also possible to determine whether to irradiate the central region R1 with the laser beam L before irradiating the central region R1 with the laser beam L.

[0206] Specifically, when the overlapped wafer T (laser absorption layer P) is irradiated with a laser beam, first, the position information of the peripheral region R2 is acquired before the peripheral region R2 is irradiated with the laser beam L. As an example, the acquired position information may be a displacement amount (the distance between the acquisition unit and the overlapped wafer T) obtained by a displacement meter such as a length measuring sensor.

[0207] When the position information of the outer peripheral region R2 is acquired, next, the outer peripheral region R2 is started to be irradiated with the laser beam L. The irradiation method of the outer peripheral region R2 with the laser beam L is the same as the irradiation method of the laser beam L described above.

[0208] Next, the position information of the peripheral region R2 is acquired again before the central region R1 is irradiated with the laser beam L. Alternatively, the position information may be acquired again by temporarily interrupting the laser processing (overlapping the rotation of the wafer T and the irradiation of the laser beam L) before the central region R1 is irradiated with the laser beam L, or the position information may be acquired again continuously during the laser processing of the peripheral region R2.

[0209] Here, when the position information of the peripheral region R2 does not change before and after the laser beam is irradiated to the peripheral region R2, or when there is no change above a predetermined threshold value, it is considered that the interface between the second wafer W2 and the laser absorption layer P in the peripheral region R2 is not completely peeled off, and the bonding strength is still maintained. On the other hand, when the position information of the peripheral region R2 changes above a threshold value before and after the laser beam L is irradiated, it can be considered that peeling occurs at the interface between the second wafer W2 and the laser absorption layer P for some reason during the process of irradiating the laser beam L to the peripheral region R2, thereby reducing the bonding strength.

[0210] Therefore, when the position information of the outer peripheral region R2 does not change by more than the threshold value before and after the irradiation with the laser beam L and it can be considered that the bonding strength is maintained, the irradiation of the laser beam L to the central region R1 is continued.

[0211] Thereafter, the overlapped wafer T in which the bonding strength between the second wafer W2 and the laser absorption layer P has been reduced is transported to the separation device 32 , and the first wafer W1 and the second wafer W2 are separated.

[0212] On the other hand, if the position information of the peripheral region R2 changes by a threshold value or more before and after irradiation with the laser beam L and it can be considered that the bonding strength has decreased, the central region R1 is not irradiated with the laser beam L. Thus, the bonding strength between the second wafer W2 and the laser absorption layer P is maintained in the central region R1.

[0213] 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 the overlapped wafer T may be removed from the laser irradiation device by manual recovery by an operator.

[0214] In this way, for example, by determining whether to irradiate the central area R1 with the laser beam L based on the peeling state of the peripheral area R2, complete peeling of the entire interface between the second wafer W2 and the laser absorption layer P, including the central area R1, can be suppressed, thereby enabling the overlapping wafer T to be safely moved out without causing the second wafer W2 to fall in the laser irradiation device.

[0215] In addition, in the present description, the position information of the peripheral region R2 is acquired before the peripheral region R2 is irradiated with the laser beam L, and the peeling state is determined by comparing the position information before the irradiation with the position information after the irradiation with the laser beam L. However, if the peeling state of the peripheral region R2 can be determined without comparing the position information before and after the irradiation with the laser beam L, it is not necessary to acquire the position information before the irradiation with the laser beam L, and it is sufficient to acquire the position information before the irradiation with the laser beam L at least to confirm the peeling state.

[0216] In addition, in the above embodiment, a laser absorption layer P, a device layer D2 and a surface film F2 are sequentially stacked on the surface W2a of the second wafer W2, and the interface between the laser absorption layer P and the second wafer W2 is set as a separation surface between the first wafer W1 and the second wafer W2, but the position of the separation surface is not limited thereto.

[0217] Specifically, for example, a peeling-promoting film (not shown) for promoting the peeling of the first wafer W1 and the second wafer W2 may be formed on the surface W2a side of the second wafer W2 and between the second wafer W2 and the laser absorption layer P, and the interface between the peeling-promoting film and the second wafer W2 is set as a separation surface. In this case, as a material constituting the peeling-promoting film, it is desirable to select a material whose adhesion between the peeling-promoting film and the second wafer W2 (silicon, etc.) is at least smaller than the adhesion between the peeling-promoting film and the laser absorption layer P (oxide film).

[0218] The embodiments disclosed herein are to be considered in all respects as illustrative and non-restrictive. The above embodiments may be omitted, replaced, or modified in various ways without departing from the appended claims and the gist thereof.

[0219] Description of Reference Numerals

[0220] 1: wafer processing system; 31: laser irradiation device; 40: control device; 100: holding disk; 104: rotation mechanism; 105: driving mechanism; 108: contact sensor; 110: laser irradiation unit; 120: camera mechanism; L: laser beam; T: overlapping wafers; W1: first wafer; W2: second wafer.

Claims

1. A substrate processing system for processing a substrate, the substrate processing system comprising: a substrate holding portion having a holding surface for holding the substrate; a driving mechanism that moves the substrate holding portion in a horizontal direction; a rotating mechanism that rotates the substrate holding portion; a laser irradiation unit that irradiates the substrate held on the holding surface with a laser beam to form a separation surface that is a base point for separation of the substrate; and A detection mechanism is used to detect separation of the substrate held on the substrate holding portion with the separation surface as a base point.

2. The substrate processing system according to claim 1, wherein: The detection mechanism comprises: an acquisition unit that acquires at least position information of an upper substrate above the separation surface among the substrates; and A determination unit determines the separation of the upper substrate based on the position information acquired by the acquisition unit.

3. The substrate processing system according to claim 2, wherein: The detection mechanism acquires position information of the upper substrate before and after irradiation of the laser beam to detect the horizontal displacement of the center of the upper substrate relative to the center of the substrate holding portion before and after irradiation of the laser beam, The detection mechanism determines the separation of the upper substrate based on a difference between the displacement amount before irradiation with the laser beam and the displacement amount after irradiation with the laser beam.

4. The substrate processing system according to claim 2, wherein: Before and after irradiation with the laser beam, the detection mechanism obtains position information of the upper substrate and the lower substrate below the separation surface in the substrate to detect the horizontal displacement of the upper substrate relative to the lower substrate before and after irradiation with the laser beam. The detection mechanism determines the separation of the upper substrate based on a difference between the displacement amount before irradiation with the laser beam and the displacement amount after irradiation with the laser beam.

5. The substrate processing system according to claim 2, wherein: After irradiating the laser beam, the detection mechanism obtains position information of the upper substrate and the lower substrate below the separation surface in the substrate to detect the horizontal displacement of the upper substrate relative to the lower substrate. The detection mechanism determines the separation of the upper substrate based on the displacement amount.

6. The substrate processing system according to claim 2, wherein: The detection mechanism obtains the position information of the upper substrate in the height direction, and determines the separation of the upper substrate based on the change in the height position of the upper substrate before and after irradiation with the laser beam, or the difference between a pre-set reference horizontal plane and the obtained position information of the upper substrate in the height direction.

7. The substrate processing system according to claim 1, wherein: The detection mechanism comprises: a plurality of touch sensors arranged so as to surround the substrate on the holding surface; and a determination unit that determines the separation of the substrate based on information detected by the contact sensor, The determination unit determines the separation of the upper substrate by detecting contact between an upper substrate above the separation surface among the substrates and the contact sensor.

8. The substrate processing system according to claim 1, wherein: The detection mechanism comprises a spectroscopic interferometer, and the spectroscopic interferometer is used to detect a first height position and a second height position in a thickness direction of the substrate, wherein the first height position is different from the second height position. The spectroscopic interferometer has: a head that irradiates a measuring 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; and An analysis unit measures a distance between the first height position and the second height position based on interference of the reflected light.

9. The substrate processing system according to claim 1, wherein: The substrate holding portion comprises: a plurality of lift pins for supporting the substrate held on the holding surface from below and lifting the substrate; as well as A plurality of substrate drop prevention pins are arranged so as to surround the substrate held on the holding surface and are configured to be able to be raised and lowered integrally with the lifting pins.

10. The substrate processing system according to claim 1, wherein: A substrate transport mechanism is also provided, and the substrate transport mechanism transports the substrate. The substrate transport mechanism includes a plurality of transport arms. At least one of the plurality of transfer arms has a plurality of guide pins arranged so as to surround the substrate. The substrate transport mechanism holds and transports the substrate irradiated with the laser beam to be transported from the laser irradiation section to a separation section that separates the substrate with the separation surface as a base point, using the transport arm having the guide pin.

11. The substrate processing system according to claim 1, wherein: The driving mechanism is configured to move the substrate holding portion between a handover position and a processing position, wherein the handover position is a position where the substrate is handed over to the substrate holding portion, and the processing position is a position where the separation surface is formed by irradiating the laser beam. The control mechanism for controlling at least the action of the driving mechanism performs the following control: the acceleration of the substrate holding portion when moving from the processing position to the handover position after irradiation with the laser beam is greater than the acceleration of the substrate holding portion when moving from the handover position to the processing position before irradiation with the laser beam.

12. The substrate processing system according to any one of claims 1 to 11, wherein: Also available: A separation unit, which separates the substrate based on the separation surface; a substrate transport mechanism that transports the substrate; and Controlling bodies, When the detection mechanism detects the separation of the substrate based on the separation surface, the control mechanism performs the following control: the substrate is transported to the separation portion using the substrate transport mechanism, and the transport speed of the substrate when transported to the separation portion is set to be lower than a specified speed.

13. The substrate processing system according to any one of claims 1 to 11, wherein: Also available: A substrate transporting mechanism, which transports the substrate; a transfer pad that sucks and holds the substrate held by the substrate holding portion from above the substrate; and Controlling bodies, When the detection mechanism detects the separation of the substrate with the separation surface as the base point, the control mechanism performs the following control: The upper substrate above the separation surface is adsorbed and held by the conveying pad, and the upper substrate is retracted from the lower substrate below the separation surface; transporting the lower substrate held by the substrate holding portion by the substrate transport mechanism; and The upper substrate held by suction by the transfer pad is delivered to the substrate transfer mechanism, and then the upper substrate is transferred.

14. The substrate processing system according to any one of claims 1 to 11, wherein: Also available: A separation part, which separates the substrate based on the separation surface; a substrate transport mechanism that transports the substrate; and Controlling bodies, When the detection mechanism does not detect the separation of the substrate with the separation surface as a base point, the control mechanism performs the following control: using the substrate conveying mechanism to convey the substrate after the separation surface is formed to the separation portion.

15. A substrate processing method for processing a substrate, the substrate processing method comprising: providing the substrate to a holding surface of a substrate holding portion; irradiating the substrate held on the holding surface with a laser beam to form a separation surface serving as a base point for separation of the substrate; and Separation of the substrate held on the substrate holding portion with the separation surface as a base point is detected.

16. The substrate processing method according to claim 15, wherein: Detecting the separation of the substrate comprises: acquiring at least position information of an upper substrate above the separation surface among the substrates; and Based on the acquired position information, the separation of the upper substrate is determined.

17. The substrate processing method according to claim 16, wherein: When detecting separation of the substrate, Before and after the laser beam is irradiated, position information of the upper substrate is acquired to detect the horizontal displacement of the center of the upper substrate relative to the center of the substrate holding portion before and after the laser beam is irradiated, The separation of the upper substrate is determined based on a difference between the displacement amount before the laser beam is irradiated and the displacement amount after the laser beam is irradiated.

18. The substrate processing method according to claim 16, wherein: When detecting separation of the substrate, Before and after irradiation with the laser beam, position information of the upper substrate and the lower substrate below the separation surface in the substrate is acquired to detect the horizontal displacement of the upper substrate relative to the lower substrate before and after irradiation with the laser beam, The separation of the upper substrate is determined based on a difference between the displacement amount before the laser beam is irradiated and the displacement amount after the laser beam is irradiated.

19. The substrate processing method according to claim 16, wherein: When detecting separation of the substrate, After irradiating the laser beam, position information of the upper substrate and the lower substrate below the separation surface in the substrate is acquired to detect the horizontal displacement of the upper substrate relative to the lower substrate, The separation of the upper substrate is determined based on the amount of displacement.

20. The substrate processing method according to claim 16, wherein: When detecting separation of the substrate, The position information of the upper substrate in the height direction is obtained, and the separation of the upper substrate is determined based on the change in the height position of the upper substrate before and after irradiation with the laser beam, or the difference between a pre-set reference horizontal plane and the obtained position information of the upper substrate in the height direction.

21. The substrate processing method according to claim 15, wherein: The detection of separation of the substrate is determined by detecting contact between a plurality of contact sensors arranged to surround the substrate on the holding surface and an upper substrate above the separation surface among the substrates.

22. The substrate processing method according to claim 15, wherein: The detection of the separation of the substrate is determined by detecting a first height position and a second height position in a thickness direction of the substrate, the first height position being different from the second height position.

23. The substrate processing method according to claim 15, wherein: In a laser irradiation device for irradiating the substrate with the laser beam, The substrate holding portion is configured to be movable between a handover position and a processing position, wherein the handover position is a position where the substrate is handed over to the substrate holding portion, and the processing position is a position where the separation surface is formed by irradiating the laser beam. The substrate holding portion moves from the processing position to the delivery position at a greater acceleration after irradiation with the laser beam than before irradiation with the laser beam.

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