Substrate processing apparatus and substrate processing method

Abstract

Provided is a substrate processing device for processing a substrate, the substrate processing device comprising: a substrate holding portion having a holding surface for the substrate; a rotating mechanism for rotating the substrate on the holding surface centered on the axis of rotation of the substrate holding portion; and a laser irradiation portion for irradiating the substrate on the holding surface with a laser beam. The holding surface of the substrate holding portion has a diameter smaller than that of the substrate.

Description

Technical Field

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

Background Art

[0002] Patent Document 1 discloses a substrate processing method in which a laser beam is pulsed onto a laser absorption layer of a polymerized substrate. In such a substrate processing method, the laser beam is irradiated from the outer peripheral portion to the central portion of the laser absorption layer.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The technology according to the present disclosure suppresses damage to the substrate support surface by the laser beam when irradiating and processing the substrate on the substrate holding surface with the laser beam.

Means for Solving the Problems

[0005] One aspect of the present disclosure is a substrate processing apparatus for processing a substrate, including a substrate holding portion having a holding surface of the substrate, a rotation mechanism for rotating the substrate on the holding surface about a rotation axis of the substrate holding portion, and a laser irradiation portion for irradiating the substrate on the holding surface with a laser beam. A light-shielding portion that receives the laser light from the laser irradiation portion is located at a position surrounding a part of the periphery of the substrate holding portion or the entire periphery of the periphery. and.

Effects of the Invention

[0006] According to the present disclosure, it is possible to suppress damage to the substrate support surface by the laser beam when irradiating and processing the substrate on the substrate holding surface with the laser beam.

Brief Description of the Drawings

[0007] [Figure 1] This is a side view showing a schematic configuration of the polymerized wafer to be processed. [Figure 2] This is a schematic plan view illustrating the general configuration of the wafer processing system. [Figure 3] This is a side view showing a schematic configuration of a wafer processing apparatus according to the first embodiment. [Figure 4] This is a plan view showing a schematic configuration of a wafer processing apparatus according to the first embodiment. [Figure 5] This is an explanatory diagram showing the state of a polymerized wafer held by adsorption on a chuck. [Figure 6] This is a side view showing another example of the configuration of a chuck in a wafer processing device. [Figure 7] This is a side view showing another example of the configuration of a chuck in a wafer processing device. [Figure 8] This is a side view showing another example of the configuration of a chuck in a wafer processing device. [Figure 9] This is a side view showing another example of a wafer fall prevention pin configuration. [Figure 10] This is a side view showing another example of a wafer fall prevention pin configuration. [Figure 11] This is an explanatory diagram showing how laser light is irradiated onto a laser absorption layer. [Figure 12] This is an explanatory diagram showing the process of peeling the first wafer from the laser absorption layer. [Figure 13] This is an explanatory diagram showing an example of laser light irradiation on a laser absorption layer. [Figure 14] This is an explanatory diagram showing a conventional method for determining the irradiation position of laser light. [Figure 15] This is an explanatory diagram showing a method for determining the irradiation position of laser light according to an embodiment. [Figure 16] This is an explanatory diagram showing a method for determining the irradiation position of laser light according to an embodiment. [Figure 17] This is an explanatory diagram showing other examples of laser light irradiation of the laser absorption layer. [Figure 18] This is a plan view showing a schematic configuration of a wafer processing apparatus according to the second embodiment. [Figure 19] It is a front view showing an outline of the configuration of a wafer processing apparatus according to a second embodiment. [Figure 20] It is an explanatory diagram showing the state of reflection of laser light by a beam damper. [Figure 21] It is an explanatory diagram showing the state of exhaust by a dust collection unit.

Mode for Carrying Out the Invention

[0008] In the manufacturing process of semiconductor devices, in a polymerized wafer in which two semiconductor substrates (hereinafter referred to as "wafers") are bonded, a device layer formed on the surface of the first wafer is transferred to the second wafer. This transfer of the device layer is performed, for example, using laser lift-off. That is, laser light is irradiated onto a laser absorption layer formed between the first wafer and the device layer, and the first wafer and the laser absorption layer are peeled off to transfer the device layer to the second wafer.

[0009] In laser lift-off, the polymerized wafer held on the substrate holding portion is rotated, and while the laser light is relatively moved in the radial direction with respect to the polymerized wafer, the laser light is irradiated in a pulsed manner.

[0010] At this time, if the polymerized wafer is held eccentrically with respect to the substrate holding portion, that is, if there is a deviation between the rotation center of the substrate holding portion and the center of the polymerized wafer, the distance between the rotation center of the substrate holding portion and the outer end portion of the polymerized wafer changes in the circumferential direction. Therefore, when the irradiation position of the laser beam is set at the outer end portion position of the polymerized wafer, when irradiating the laser beam while rotating the polymerized wafer, there is a risk that the laser beam will be irradiated radially outside the outer end portion of the polymerized wafer in the circumferential direction. Also at this time, when the size of the substrate holding surface of the substrate holding portion is equal to or larger than the size of the polymerized wafer, the laser beam is irradiated to the substrate holding surface of the substrate holding portion, which may damage the substrate holding surface. And when damage occurs on the substrate holding surface in this way, there is a risk of damaging the polymerized wafer held by the substrate holding portion next, a risk of affecting the holding of the polymerized wafer by the substrate holding portion, or a risk of causing a processing defect due to a change in the upper surface height position of the polymerized wafer on the substrate holding portion.

[0011] The technology according to the present disclosure has been made in view of the above circumstances, and suppresses damage to the substrate support surface by the laser beam when irradiating and processing the substrate on the substrate holding surface with the laser beam. Hereinafter, a wafer processing system including a wafer processing apparatus as the substrate processing apparatus according to the present embodiment and a wafer processing method as the substrate processing method will be described with reference to the drawings. In the present specification and drawings, elements having substantially the same functional configuration are denoted by the same reference numerals, and redundant description is omitted.

[0012] In the wafer processing system 1 according to the present embodiment described later, as shown in FIG. 1, processing is performed on a polymerized wafer T as a substrate in which a first wafer W and a second wafer S are joined. Hereinafter, in the first wafer W, the surface on the side joined to the second wafer S is referred to as a front surface Wa, and the surface on the opposite side of the front surface Wa is referred to as a back surface Wb. Similarly, in the second wafer S, the surface on the side joined to the first wafer W is referred to as a front surface Sa, and the surface on the opposite side of the front surface Sa is referred to as a back surface Sb.

[0013] The first wafer W is a semiconductor wafer, such as a silicon substrate. In this embodiment, the first wafer W has a substantially disc shape. A laser absorption layer P, a device layer Dw, and a surface film Fw are stacked on the surface Wa of the first wafer W in this order from the surface Wa side. The laser absorption layer P absorbs laser light irradiated from the laser irradiation unit 110, as will be described later. For example, an oxide film (SiO2 film) is used for the laser absorption layer P, but it is not particularly limited as long as it absorbs laser light. The device layer Dw includes a plurality of devices. Examples of surface film Fw include an oxide film (THOX film, SiO2 film, TEOS film), a SiC film, a SiCN film, or an adhesive. The position of the laser absorption layer P is not limited to the above embodiment, and may be formed, for example, between the device layer Dw and the surface film Fw. Also, there are cases where the device layer Dw and the surface film Fw are not formed on the surface Wa. In this case, the laser absorption layer P is formed on the second wafer S side, and the device layer Ds on the second wafer S side, as described later, is transferred to the first wafer W side.

[0014] The second wafer S is a semiconductor wafer, such as a silicon substrate. In this embodiment, the second wafer S has a substantially disc shape. On the surface Sa of the second wafer S, a device layer Ds and a surface film Fs are stacked in this order from the surface Sa side. The device layer Ds and the surface film Fs are the same as the device layer Dw and surface film Fw of the first wafer W, respectively. The surface film Fw of the first wafer W and the surface film Fs of the second wafer S are then bonded together. Note that the device layer Ds and surface film Fs may not be formed on the surface Sa.

[0015] As shown in Figure 2, the wafer processing system 1 has a configuration in which the loading / unloading block 10, the transport block 20, and the processing block 30 are connected as a single unit. The loading / unloading block 10 and the processing block 30 are provided around the transport block 20. Specifically, the loading / unloading block 10 is located on the negative Y-axis side of the transport block 20. The wafer processing apparatus 31, which will be described later, is located on the negative X-axis side of the transport block 20, while the cleaning apparatus 32 and the reversing apparatus 33, which will be described later, are located on the positive X-axis side of the transport block 20.

[0016] The loading / unloading block 10 loads cassettes Ct, Cw, and Cs, each capable of accommodating multiple polymerized wafers T, multiple first wafers W, and multiple second wafers S, respectively, into and out of the loading / unloading block 10. The loading / unloading block 10 is provided with a cassette mounting table 11. In the illustrated example, multiple cassettes, for example, three cassettes Ct, Cw, and Cs, can be freely mounted on the cassette mounting table 11 in a line along the X-axis. Note that the number of cassettes Ct, Cw, and Cs mounted on the cassette mounting table 11 is not limited to this embodiment and can be determined arbitrarily.

[0017] The transport block 20 is provided with a wafer transport device 22 that is configured to move along a transport path 21 extending in the X-axis direction. The wafer transport device 22 has, for example, two transport arms 23, 23 that hold and transport the polymerized wafer T, the first wafer W, or the second wafer S. Each transport arm 23 is configured to move horizontally, vertically, around the horizontal axis, and around the vertical axis. Note that the configuration of the transport arms 23 is not limited to this embodiment and can be any configuration. The wafer transport device 22 is configured to transport the polymerized wafer T, the first wafer W, and the second wafer S to the cassettes Ct, Cw, and Cs of the cassette mounting table 11, the wafer processing device 31 (described later), the cleaning device 32 (described later), and the inversion device 33 (described later).

[0018] The processing block 30 includes a wafer processing apparatus 31, a cleaning apparatus 32, and a reversing apparatus 33. In one example, the cleaning apparatus 32 and the reversing apparatus 33 are stacked on the positive X-axis side of the transport block 20.

[0019] The wafer processing apparatus 31 irradiates the laser absorption layer P of the first wafer W with laser light to reduce the bonding strength at the interface between the first wafer W and the laser absorption layer P, and then peels the first wafer W from the second wafer S using this interface as a starting point. The configuration of the wafer processing apparatus 31 will be described later.

[0020] The cleaning apparatus 32 cleans the surface of the laser absorption layer P formed on the surface Sa side of the second wafer S separated by peeling in the wafer processing apparatus 31. For example, a brush is brought into contact with the surface of the laser absorption layer P to scrub the surface. Pressurized cleaning solution may also be used for surface cleaning. The cleaning apparatus 32 may also be configured to clean the back surface Sb of the second wafer S along with the surface Sa side.

[0021] The inversion device 33 inverts the front and back surfaces of the first wafer W that has been peeled off from the second wafer S by the wafer processing device 31. The configuration of the inversion device 33 is not particularly limited.

[0022] The wafer processing system 1 described above is provided with a control device 40 as a control unit. The control device 40 is, for example, a computer and has a program storage unit (not shown). The program storage unit stores a program that controls the processing of the polymerized wafer T in the wafer processing system 1. The program storage unit also stores a program that controls the operation of the various processing devices and transport devices and other drive systems to realize the wafer processing described later in the wafer processing system 1. The above program may have been recorded on a storage medium H that is readable by the computer and installed from the storage medium H to the control device 40. The storage medium H may be temporary or permanent.

[0023] In this embodiment, as described above, the wafer processing apparatus 31 is used to separate the first wafer W from the second wafer S. However, the wafer processing system 1 may also have a separate peeling apparatus (not shown) for separating the first wafer W from the second wafer S.

[0024] Next, the wafer processing apparatus 31 described above will be explained.

[0025] As shown in Figures 3 and 4, the wafer processing apparatus 31 has a chuck 100 that holds the polymerized wafer T on its upper surface. The chuck 100 has a substrate holding portion 100a and a light-shielding portion 100b. The upper surface height of the light-shielding portion 100b is lower than the upper surface height of the substrate holding portion 100a, meaning that the chuck 100 has an upward convex shape in cross-sectional view.

[0026] The substrate holding portion 100a has a substrate holding surface on its upper surface. The substrate holding surface of the substrate holding portion 100a is configured such that it has a smaller diameter than at least the polymerized wafer T held by the substrate holding portion 100a, and preferably is sized to take into account the transport accuracy of the polymerized wafer T. More specifically, the substrate holding portion 100a is configured to hold the polymerized wafer T with its entire surface even if the polymerized wafer T is placed eccentrically due to factors such as transport accuracy. The substrate holding portion 100a then adsorbs and holds a portion of the radially inner side of the back surface Sb of the second wafer S. In other words, on the substrate holding portion 100a, the outer peripheral edge portion of the polymerized wafer T is floating above the light-shielding portion 100b. The substrate holding portion 100a is, for example, an electrostatic chuck (ESC) or a vacuum chuck.

[0027] The light-shielding portion 100b is positioned to surround the substrate holding portion 100a in a plan view. The light-shielding portion 100b is made of a material that does not transmit laser light emitted from the laser irradiation portion 110 (described later), such as ceramics or metal materials, and receives the laser light emitted from the laser irradiation portion 110 that passes radially outside the polymerized wafer T on the substrate holding portion 100a, thereby suppressing the laser light L from reaching below the chuck 100.

[0028] Furthermore, the chuck 100 is provided with a plurality of wafer fall prevention pins 101, for example three, that surround the substrate holding portion 100a along the radial direction, and more specifically, surround the polymerized wafer T on the substrate holding portion 100a. The wafer fall prevention pins 101 suppress the first wafer W, after irradiation of the laser light L onto the laser absorption layer P, from falling from the chuck 100 due to, for example, centrifugal force accompanying the rotation of the chuck 100 or inertial force accompanying its movement, as will be described later. In one example, the wafer fall prevention pins 101 are fixed to the lower surface side of the light shielding portion 100b and are configured to rotate integrally with the chuck 100 by a rotation mechanism 104 described later, and to move integrally with the chuck 100 in the Y-axis direction by a movement mechanism 105.

[0029] The chuck 100 is supported by the slider table 103, which serves as a stage, via an air bearing 102. A rotation mechanism 104 is provided on the underside of the slider table 103. The rotation mechanism 104 incorporates, for example, a motor as its drive source. The chuck 100 is configured to rotate freely around the θ axis (vertical axis) via the air bearing 102 through the rotation mechanism 104. The slider table 103 is configured to move along a rail 107 that extends in the Y-axis direction and is provided on the base 106, via a moving mechanism 105 provided on its underside. The drive source for the moving mechanism 105 is not particularly limited, but for example, a linear motor can be used.

[0030] A laser irradiation unit 110 is provided above the chuck 100. The laser irradiation unit 110 includes a laser head 111, an optical system 112, and a lens 113.

[0031] The laser head 111 has a laser oscillator (not shown) that emits laser light L (see Figure 11) in a pulsed manner. This laser light L is a so-called pulsed laser. In this embodiment, the laser light L is CO2 laser light, and the wavelength of the CO2 laser light is, for example, 8.9 μm to 11 μm. The laser head 111 may also have other equipment besides the laser oscillator, such as an amplifier.

[0032] The optical system 112 includes optical elements (not shown) that control the intensity and position of the laser beam L, and an attenuator (not shown) that reduces the laser beam L to adjust the output. The optical system 112 can also control the branching of the laser beam L.

[0033] The lens 113 irradiates the polymerized wafer T held in the chuck 100 with laser light L. The laser light L emitted from the laser irradiation unit 110 passes through the first wafer W and irradiates the laser absorption layer P. The lens 113 may be configured to move up and down by a lifting mechanism (not shown).

[0034] Furthermore, an imaging mechanism 120 is provided above the chuck 100. The imaging mechanism 120 includes, for example, one or more cameras 121 selected from macro cameras, micro cameras, etc., and a calculation unit 122. The imaging mechanism 120 may be configured to move freely in the Y-axis and Z-axis directions by means of a lifting mechanism (not shown) and a moving mechanism (not shown).

[0035] Camera 121 images the outer edge of the polymerized wafer T held in the chuck 100. Camera 121 is equipped with, for example, a coaxial lens, emits infrared light (IR), and also receives reflected light from the object. The calculation unit 122 detects the position of the polymerized wafer T on the chuck 100 from the image data captured by the camera 121, and calculates the eccentricity (horizontal displacement: see Figure 5) between the rotation center of the chuck 100 and the center of the polymerized wafer T based on this information. The calculation unit 122 may be provided independently of the imaging mechanism 120 as described above, or it may be included in the control device 40. The imaging results from the camera 121 and the position and eccentricity of the polymerized wafer T calculated by the calculation unit 122 may be output to the control device 40.

[0036] In Figure 5, the chuck 100 and the polymerized wafer T are shown at a different scale than their actual size in order to clearly show the eccentricity between the rotation center of the chuck 100 and the center of the polymerized wafer T. Similarly, in other diagrams used in the explanations, the chuck 100 and the polymerized wafer T may also be shown at a different scale than their actual size.

[0037] The positional relationship between the camera 121 of the imaging mechanism 120 and the lens 113 of the laser irradiation unit 110, as well as the positional relationship between the camera 121 of the imaging mechanism 120 and the rotation center of the chuck 100, are stored in the control device 40 in advance.

[0038] A transport pad 130 is further provided above the chuck 100. The transport pad 130 is configured to be able to move up and down by a lifting mechanism (not shown). The transport pad 130 also has a suction surface for adsorbing and holding the first wafer W. The transport pad 130 then transports the first wafer W between the chuck 100 and the transport arm 23. Specifically, after moving the chuck 100 to below the transport pad 130 (the handover position with the transport arm 23), the transport pad 130 adsorbs and holds the back surface Wb of the first wafer W and detaches it from the second wafer S. Subsequently, the detached first wafer W is transferred from the transport pad 130 to the transport arm 23 and removed from the wafer processing apparatus 31.

[0039] Although the wafer processing apparatus 31 according to the embodiment is configured as described above, the configuration of the wafer processing apparatus 31 is not limited thereto.

[0040] For example, Figure 3 illustrates a case where the substrate holding portion 100a and the light-shielding portion 100b constituting the chuck 100 are integrally constructed. However, these substrate holding portion 100a and light-shielding portion 100b may be constructed as separate parts. In this case, as shown in Figure 6, the chuck 200 may be constructed by stacking and arranging a substantially disc-shaped substrate holding portion 200a having a diameter smaller than that of the polymerized wafer T, and a substantially disc-shaped light-shielding portion 200b having a diameter larger than that of the polymerized wafer T. In this case, as shown in Figure 7, the chuck 300 may be configured with a substantially disc-shaped substrate holding portion 300a having a diameter smaller than that of the polymerized wafer T, and a substantially annular light-shielding portion 300b arranged to surround the substrate holding portion 300a.

[0041] Furthermore, the chuck 400 may be composed only of a substantially disc-shaped substrate holding portion having a diameter smaller than that of the polymerized wafer T, and a cover member 401 as a light-shielding portion having a light-shielding surface may be placed below the substrate holding surface of the chuck 400. As an example, the cover member 401 may be arranged to surround the chuck 400, as shown in Figure 8. Furthermore, the cover member 401 does not need to be positioned to surround the chuck 400 all the way around, as shown in Figure 8. It is sufficient that it is positioned at least on a part of the periphery of the chuck 400 directly below the lens 113 when the irradiation position of the laser beam L is radially outward from the outer edge of the polymerized wafer T.

[0042] Furthermore, although Figure 3 illustrates an example where the wafer fall prevention pin 101 is fixed to the lower surface of the light-shielding portion 100b, the method of fixing the wafer fall prevention pin 101 is not limited to this. Specifically, for example, as shown in Figure 9, the wafer fall prevention pin 201 may be positioned to protrude upward from the upper surface of the light-shielding portion 100b. Similarly, although not shown in the figures, the wafer fall prevention pin 201 may be positioned to protrude from the upper surface of the light-shielding portions 200b, 300b shown in Figures 6 and 7, or the cover member 401 shown in Figure 8. When the wafer fall prevention pin 201 protrudes from the upper surface of the cover member 401 in this manner, it is desirable that the cover member 401 be positioned to surround the entire circumference of the chuck 400. As shown in Figure 10, the wafer fall prevention pin 301 may be positioned to protrude upward from the upper surface of the slider table 103, instead of the light-shielding portion 100b. In this case, the wafer fall prevention pin 301 is configured to move integrally with the slider table 103 in the Y-axis direction by the moving mechanism 105.

[0043] Furthermore, in this embodiment, for example, the first wafer W is separated from the second wafer S using the transport pad 130 of the wafer processing apparatus 31. However, as described above, if a peeling device (not shown) is independently arranged in the wafer processing system 1, the peeling device may be used instead of the transport pad 130 to peel off the first wafer W. In this case, the transport pad 130 does not peel the first wafer W from the second wafer S, but instead transfers the polymerized wafer T to the transport arm 23.

[0044] Next, a wafer processing procedure performed using the wafer processing system 1 configured as described above will be explained. In this embodiment, the first wafer W and the second wafer S are bonded together in an external bonding device (not shown) to the wafer processing system 1 to form a polymerized wafer T in advance.

[0045] First, a cassette Ct containing multiple polymerized wafers T is placed on the cassette mounting table 11 of the loading / unloading block 10.

[0046] Next, the polymerized wafer T is removed from the cassette Ct by the wafer transport device 22 and transported to the wafer processing device 31. In the wafer processing device 31, the polymerized wafer T is transferred from the transport arm 23 to the chuck 100 and held by the chuck 100. Subsequently, the chuck 100 is moved to the processing position by the moving mechanism 105. This processing position is a position where laser light can be irradiated onto the polymerized wafer T (laser absorption layer P) from the laser irradiation unit 110.

[0047] Next, as shown in Figure 11, laser light L (CO2 laser light) is pulsed from the laser irradiation unit 110 onto the laser absorption layer P, and more specifically, onto the interface between the laser absorption layer P and the first wafer W. At this time, the laser light L is irradiated from the back surface Wb side of the first wafer W, passes through the first wafer W, 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 first wafer W is reduced by this laser light L. In this embodiment, "reduced bonding strength" means a state in which the bonding strength is reduced at least compared to before irradiation with laser light L, and includes modification of the laser absorption layer P and delamination of the laser absorption layer P and the first wafer W.

[0048] The specific wafer processing method in the wafer processing apparatus 31 will be described later.

[0049] Next, the chuck 100 is moved to the transfer position by the moving mechanism 105. Then, as shown in Figure 12(a), the back surface Wb of the first wafer W is held by the transport pad 130. After that, as shown in Figure 12(b), with the transport pad 130 holding the first wafer W by adsorption, the transport pad 130 is raised to detach the first wafer W from the laser absorption layer P. At this time, as described above, the bonding strength at the interface between the laser absorption layer P and the first wafer W is reduced by irradiation with laser light L, so the first wafer W can be detached from the laser absorption layer P without applying a large load.

[0050] The peeled first wafer W is transferred from the transport pad 130 to the transport arm 23 of the wafer transport device 22 and transported to the cassette Cw of the cassette mounting table 11. Alternatively, the first wafer W, after being removed from the wafer processing device 31, may be transported to the cleaning device 32 before being transported to the cassette Cw, where its peeled surface Wa is cleaned. In this case, the first wafer W, after being removed from the wafer processing device 31, may be inverted in the inversion device 33 so that the peeled surface Wa faces upwards, before being transported to the cleaning device 32.

[0051] Meanwhile, the second wafer S, held in the chuck 100, is transferred to the transport arm 23 and transported to the cleaning device 32. In the cleaning device 32, the surface of the laser absorption layer P, which is the delamination surface, is scrubbed clean. In addition, the back surface Sb of the second wafer S may be cleaned along with the surface of the laser absorption layer P in the cleaning device 32. Alternatively, separate cleaning units may be provided for cleaning the surface of the laser absorption layer P and the back surface Sb of the second wafer S, respectively.

[0052] Subsequently, the second wafer S, having undergone all processing, is transported by the wafer transport device 22 to the cassette Cs on the cassette tray 11. This completes the series of wafer processing steps in the wafer processing system 1.

[0053] Next, the method of irradiating the wafer processing apparatus 31 with laser light L, as described above, will be explained.

[0054] In this embodiment, the polymerized wafer T held in the chuck 100 is rotated, and the polymerized wafer T is moved radially, thereby irradiating the laser beam L in a pulsed manner while moving the irradiation position of the laser beam L from the radial outside to the inside. In this case, in order to uniformly separate the first wafer W and the laser absorption layer P across the wafer surface, if the interval between irradiations of the laser beam L is kept constant, as the irradiation position of the laser beam L moves from the radial outside to the inside, more specifically as it approaches the rotation center of the chuck 100, the peripheral speed of the polymerized wafer T at the irradiation position of the laser beam L decreases, so it is necessary to increase the rotation speed of the polymerized wafer T. However, if the rotation speed of the polymerized wafer T is increased in this way, there is a risk that the first wafer W may separate from the second wafer S due to the centrifugal force accompanying the rotation of the polymerized wafer T, even during the irradiation of the laser beam L. Therefore, in this embodiment, when irradiating the outer peripheral region R2 (see Figure 13) of the chuck 100 where the rotation speed of the polymerized wafer T is relatively slow with the laser beam L, the polymerized wafer T is rotated, and when irradiating the central region R1 (see Figure 13) of the chuck 100 where the rotation speed of the polymerized wafer T is faster with the laser beam L scanned while the rotation of the polymerized wafer T is stopped.

[0055] The central region R1 of the chuck 100, which scans the laser beam L, is set in advance of wafer processing in the wafer processing apparatus 31 as a circular region having a desired diameter length with respect to the rotation center of the chuck 100. The diameter length of the central region R1 is, for example, the radial position where the relative rotation speed of the chuck 100 with respect to the lens 113 of the laser irradiation unit 110 reaches its upper limit; in other words, it is the limit position where the laser beam L does not overlap. The diameter length of the central region R1 is approximately 10 mm as an example. Furthermore, the outer peripheral region R2, which rotates the chuck 100 when the laser beam L is irradiated, is set to be radially outward from the central region R1.

[0056] During wafer processing in the wafer processing apparatus 31, first, the outer edge of the polymerized wafer T on the chuck 100, which has been moved to the processing position, is imaged using the imaging mechanism 120. Specifically, while the chuck 100 is rotated, the camera 121 captures images of the outer edge of the polymerized wafer T (first wafer W) in a 360-degree circumferential direction.

[0057] Next, based on the imaging results from camera 121, the eccentricity between the rotation center of chuck 100 and the center of the polymerized wafer T (see Figure 5) is calculated. Specifically, the position of the outer edge of the polymerized wafer T (first wafer W) in the circumferential 360 degrees is detected from the image captured by camera 121, and the center position of the polymerized wafer T is calculated based on this. As mentioned above, the positional relationship between camera 121 and chuck 100 is stored in the control device 40 in advance. Therefore, by comparing this positional relationship between camera 121 and chuck 100 with the calculated center position of the polymerized wafer T, the eccentricity between the rotation center of chuck 100 and the center of the polymerized wafer T can be calculated.

[0058] If the calculated eccentricity is large and exceeds a predetermined threshold, the processing in the wafer processing apparatus 31 may not be started, and the polymerized wafer T to be processed may be removed from the wafer processing apparatus 31. In this case, the operator may be notified of the stoppage of processing, for example, by issuing an alarm. Alternatively, if the eccentricity exceeds the threshold in this way, the polymerized wafer T on the chuck 100 may be held by the transport pad 130, and the polymerized wafer T may be placed back on the chuck 100. The threshold used as the basis for stopping wafer processing may be set to, for example, the value at which the substrate holding surface is exposed when the chuck 100 holds the polymerized wafer T.

[0059] Next, the positions of the central region R1 and the outer peripheral region R2 of the chuck 100 are acquired, and these central region R1 and outer peripheral region R2 are set relative to the polymerized wafer T that is the target of laser light L irradiation. More specifically, within the plane of the polymerized wafer T held by the chuck 100, regions corresponding to the aforementioned central region R1 and outer peripheral region R2 (regions that overlap with these central region R1 and outer peripheral region R2 in a plan view) are set. The positions of the central region R1 and outer peripheral region R2 of the chuck 100 may be acquired from those that have been set based on the rotation center of the chuck 100 as described above and have been pre-output to the control device 40.

[0060] Next, the irradiation position of the laser beam L onto the polymerized wafer T (more specifically, the laser absorption layer P) is set. The irradiation position of the laser beam L onto the polymerized wafer T is set for each region corresponding to the central region R1 and the outer peripheral region R2 of the chuck 100 set on the polymerized wafer T. That is, the irradiation position is set by dividing it into two regions: one where the laser beam L is irradiated onto the polymerized wafer T while the chuck 100 is rotating, and another where the rotation of the chuck 100 is stopped and the laser beam L is irradiated onto the polymerized wafer T while scanning the lens 113. In the following explanation, the region radially outside the outer peripheral region R2, including the laser beam L irradiation start position, may be referred to as the "edge-side region R2e," and the region radially inside the outer peripheral region R2, including the laser beam L irradiation end position, may be referred to as the "center-side region R2c." The edge-side region R2e is located near the outer peripheral edge of the polymerized wafer T. The center-side region R2c is located near the center of the polymerized wafer T.

[0061] Here, if the irradiation position of the laser beam L to the region corresponding to the outer peripheral region R2 is determined based on the outer edge position of the polymerized wafer T, then due to various factors such as the beam diameter and index amount (the distance between irradiations of the laser beam L), the reduction in bonding strength due to irradiation with the laser beam L may extend to the central region R1, as shown in Figure 14(a). Furthermore, if the bonding strength in a part of the central region R1 is reduced by irradiation with laser light L, which is intended to reduce the bonding strength in the region corresponding to the outer peripheral region R2, then when laser light L is subsequently irradiated to the region corresponding to the central region R1, the irradiation position of the laser light L overlaps with the area where the bonding strength has decreased, as shown in Figure 14(b). As a result, there is a risk of damaging the device layer Dw formed below the laser absorption layer P.

[0062] Therefore, in the wafer processing apparatus 31 according to this embodiment, the irradiation position of the laser beam L onto the polymerized wafer T in the region corresponding to the outer peripheral region R2 is determined with reference to the rotation center position of the chuck 100.

[0063] Specifically, in this embodiment, the irradiation position of the laser beam L to the area corresponding to the center-side area R2c of the outer peripheral area R2 is set considering the size of the central area R1, which is set with respect to the rotation center of the chuck 100, and the beam diameter of the laser beam L to be irradiated. More specifically, as shown in Figure 15(a), the radial position obtained by adding the radius of the central area R1 (r1) and the beam radius of the laser beam L (r2), with respect to the rotation center of the chuck 100, is set as the irradiation position of the laser beam L. As a result, the portion of the bonding strength reduced by irradiation with the laser beam L is arranged circumferentially along the boundary between the central area R1 and the outer peripheral area R2 in the center-side area R2c.

[0064] Then, the irradiation position of the laser beam L to the region corresponding to the edge-side region R2e of the outer peripheral region R2 is set based on the irradiation position of the innermost laser beam L in the center-side region R2c (P1 in Figure 15(b)), which has been determined in this way. Specifically, as shown in Figure 15(b), the distance from the center-side region R2c to the polymerized wafer T in the radial direction is calculated from "beam diameter of laser beam L (r)" × "natural number (N) which is the number of laser beam L irradiations in the radial direction". The position (PN in Figure 15(b)) where this distance is closest to the distance (r3) from the outer edge of the polymerized wafer T to the irradiation position of the innermost laser beam L in the center-side region R2c (P1 in Figure 15(b)), as detected from the imaging results by camera 121, is set as the irradiation start position of the laser beam L in the edge-side region R2e.

[0065] Furthermore, when setting the irradiation start position of the laser beam L, the eccentricity between the rotation center of the chuck 100 and the center of the polymerized wafer T, calculated from the imaging results by the camera 121, is taken into consideration. That is, taking into account the calculated eccentricity, as shown in Figure 16, the outer edge position of the polymerized wafer T furthest from the rotation center position of the chuck 100, which is the reference for the irradiation position of the laser beam L to the outer peripheral region R2 and the corresponding region, is determined as the irradiation start position of the laser beam L in the edge-side region R2e. This allows the entire surface of the polymerized wafer T (laser absorption layer P) to be properly irradiated with laser light L, even when the polymerized wafer T is held eccentrically with respect to the chuck 100.

[0066] Once the irradiation position of the laser beam L to the region corresponding to the outer peripheral region R2 is determined, the irradiation of the polymerized wafer T (laser absorption layer P) in the region corresponding to the outer peripheral region R2 is then started. At this time, the wafer processing apparatus 31 repeatedly alternately rotates the chuck 100 (polymerized wafer T) by the rotation mechanism 104 and moves the chuck 100 (polymerized wafer T) in the Y-axis direction by the movement mechanism 105 while irradiating the laser beam L in a pulsed manner from the laser irradiation unit 110. As a result, as shown in Figure 13, the laser beam L is irradiated in the outer peripheral region R2 from the radially outer side toward the inside, concentrically with the chuck 100. When the polymerized wafer T (laser absorption layer P) is irradiated with laser beam L, the bonding strength at the interface between the laser absorption layer P and the first wafer W decreases.

[0067] Furthermore, in order to improve the throughput of wafer processing, the laser beam L may be split by the optical system 112 described above, and the laser beam L may be irradiated simultaneously at multiple points on the laser absorption layer P.

[0068] According to this embodiment, the substrate holding portion 100a of the chuck 100 is configured to have a diameter smaller than the polymerized wafer T held by the substrate holding portion 100a, as described above, and preferably to be sized to take into account the transport accuracy of the polymerized wafer T. Therefore, as described above, even if the position of the outer edge of the polymerized wafer T changes with the rotation of the chuck 100 and the polymerized wafer T is not positioned directly under the irradiation of the laser light L by the laser irradiation portion 110, the substrate holding portion 100a that substantially holds the polymerized wafer T is not irradiated with the laser light L, that is, damage to the substrate holding portion 100a can be appropriately suppressed. In this case, instead of the substrate holding portion 100a, the light-shielding portion 100b is exposed directly beneath the laser beam L irradiated by the laser irradiation portion 110. As a result, even if the polymerized wafer T is not placed directly beneath the irradiation, the laser beam L irradiates the light-shielding portion 100b, thereby preventing damage to components placed below the chuck 100 and suppressing the generation of particles caused by the irradiation of the laser beam L.

[0069] Furthermore, according to this embodiment, the light-shielding part 100b The upper surface height is configured to be lower than at least the upper surface height of the substrate holding portion 100a. As a result, even when the laser beam L is irradiated onto the light-shielding portion 100b as described above, the laser beam L is directed to the substrate holding portion 100a Because the laser beam is focused and irradiated onto the polymerized wafer T above, the distance from the focal point to the upper surface of the light-shielding portion 100b irradiated by the laser beam L increases. As a result, damage to the light-shielding portion 100b and the generation of particles can be suppressed (focus shifting). Also, the light-shielding part 100b The upper surface height of the light-shielding part is configured to be lower than at least the upper surface height of the substrate holding part 100a. 100b The substrate holding part 100a Interference with the upper polymerized wafer T is suppressed.

[0070] Furthermore, since the light-shielding portion 100b is positioned around the substrate holding portion 100a in this manner, even if the polymerized wafer T is not placed directly beneath the irradiation point, the laser beam L is prevented from escaping below the chuck 100. However, even when the light-shielding portion 100b is positioned in this manner, the laser beam L may be irradiated only when the polymerized wafer T is placed directly beneath the irradiation point of the laser beam L, and the irradiation of the laser beam L may be stopped when the light-shielding portion 100b is exposed directly beneath the irradiation point of the laser beam L. In other words, so-called on / off control may be implemented depending on whether the polymerized wafer T is placed directly beneath the irradiation point of the laser beam L or whether the light-shielding portion 100b is exposed. On / off control related to the irradiation of the laser beam L is controlled, for example, by the control device 40. By controlling the irradiation of the laser beam L on and off in this manner, the number of times the laser beam L is irradiated onto the light-shielding portion 100b is reduced, and as a result, the lifespan of the light-shielding portion 100b can be extended.

[0071] When controlling the irradiation of the laser light L in this manner, the determination of whether or not a polymerized wafer T exists directly beneath the irradiation of the laser light L, that is, whether or not the light-shielding portion 100b is exposed directly beneath the irradiation of the laser light L, may be made based on the imaging results obtained by the imaging mechanism 120 described above.

[0072] Furthermore, the on / off control of the laser beam L irradiation described above may be performed not only when the light-shielding portion 100b is exposed directly beneath the irradiation of the laser beam L, but also when the light-shielding portion 100b is not directly beneath the irradiation of the laser beam L, or when, as described above, the eccentricity exceeds a threshold and there is a possibility that the substrate holding surface will be exposed directly beneath the irradiation of the laser beam L.

[0073] Once the irradiation of the outer peripheral region R2 and the corresponding region with laser light L (reduction of the bonding strength between the first wafer W and the laser absorption layer P) is complete, the irradiation of the polymerized wafer T (laser absorption layer P) in the central region R1 and the corresponding region with laser light L is started. When irradiating the central region R1 and the corresponding region with laser light L, the rotation of the chuck 100 is stopped. Then, while irradiating the laser light L in a pulsed manner from the laser irradiation unit 110, the scanning of the irradiation position of the laser light L in the X-axis direction and the movement of the chuck 100 (polymerized wafer T) in the Y-axis direction by the moving mechanism 105 are repeatedly performed alternately (see Figure 13).

[0074] The method of irradiating the central region R1 and the corresponding region with laser light L is not limited to the example shown in Figure 13. For example, when irradiating the central region R1 and the corresponding region with laser light L, the rotation of the chuck 100 is stopped. Then, while irradiating the laser light L from the laser irradiation unit 110 in a pulsed manner, the irradiation position of the laser light L may be moved in an annular or spiral manner, gradually becoming a smaller circle from the outer periphery of the central region R1 towards the center.

[0075] According to this embodiment, as shown in Figure 15, when the laser beam L is irradiated onto the outer peripheral region R2, the reduction in bonding strength is suppressed in the central region R1. Therefore, when the laser beam L is irradiated onto the central region R1 and the corresponding region, the overlap of the laser beam L irradiation areas as shown in Figure 14 is appropriately suppressed. As a result, the entire surface of the first wafer W can be appropriately peeled off from the laser absorption layer P, and damage to the device layer Dw is suppressed.

[0076] Laser light L is irradiated onto the central region R1 and the outer region R2, and the polymerized wafer T, whose bonding strength is reduced across the entire surface of the first wafer W and the laser absorption layer P, is then moved to the transfer position by the moving mechanism 105 as described above, and further, as shown in Figure 12, the first wafer W is peeled off from the laser absorption layer P by the transport pad 130.

[0077] Here, the polymerized wafer T, whose bonding strength between the first wafer W and the laser absorption layer P has decreased due to irradiation with laser light L, is moved to the transfer position by the moving mechanism 105. However, as described above, if the bonding strength between the first wafer W and the laser absorption layer P has decreased across the entire surface, there is a risk that the first wafer W may fall off the second wafer S (laser absorption layer P) due to the inertial force associated with this movement. Similarly, even while the laser beam L is being irradiated, the centrifugal force generated by the rotation of the chuck 100 may cause the first wafer W to detach from the laser absorption layer P and fall from the second wafer S.

[0078] In this regard, the wafer processing apparatus 31 according to this embodiment is provided with a plurality of wafer fall prevention pins 101, at least three of which surround the polymerized wafer T held in the substrate holding section 100a, as shown in Figures 3 and 4. As a result, in this embodiment, even if the first wafer W peels off from the laser absorption layer P due to inertial force and centrifugal force associated with the movement and rotation of the chuck 100 after irradiation of the laser beam L to the laser absorption layer P, the first wafer W is prevented from falling from the second wafer S.

[0079] In the wafer processing apparatus 31 according to this embodiment, the substrate holding section 100a that substantially holds the polymerized wafer T is configured to have a diameter smaller than the polymerized wafer T held in the substrate holding section 100a, and preferably to be of a size that takes into account the transport accuracy of the polymerized wafer T. As a result, even if the center of the polymerized wafer T is eccentric from the rotation center of the chuck 100 due to, for example, a transport error, the irradiation of the laser beam L onto the substrate holding surface of the substrate holding part 100a is suppressed.

[0080] Furthermore, in the wafer processing apparatus 31 according to this embodiment, a light-shielding portion 100b made of a material that is not transparent to laser light L is arranged to surround the substrate holding portion 100a. As a result, even when the substrate holding portion 100a is configured to have a smaller diameter than the polymerized wafer T, as described above, it is possible to suppress the leakage and irradiation of laser light L below the chuck 100, thereby suppressing damage to internal components of the device and the generation of particles.

[0081] Furthermore, according to the wafer processing method using the wafer processing apparatus of this embodiment, the reference for the irradiation position of the laser beam L on the polymerized wafer T (laser absorption layer P) is set to the rotation center of the chuck 100, and the irradiation position of the laser beam L on the edge-side region R2e, including the irradiation start position of the laser beam L, is determined to be the radial position where the eccentricity between the center of the polymerized wafer T and the rotation center of the chuck 100 is greatest. As a result, even if the center of the polymerized wafer T is eccentric from the rotation center of the chuck 100 due to, for example, a transport error, the entire surface of the laser absorption layer P can be properly irradiated with laser light L, that is, the entire surface of the first wafer W can be properly peeled off from the laser absorption layer P.

[0082] Furthermore, in the wafer processing method according to this embodiment, the irradiation position of the laser beam L on the center-side region R2c, which includes the termination position of irradiation of the laser beam L to the outer peripheral region R2 and the region corresponding to it, is set to a radial position obtained by adding the radius of the central region R1 (r1) and the beam radius of the laser beam L (r2), with respect to the rotation center of the chuck 100. This suppresses the influence of the laser beam L irradiated onto the outer region R2 (the range of reduced bonding strength) from extending to the central region R1. Furthermore, when irradiating the central region R1 with the laser beam L, this prevents the irradiation range of the laser beam L from overlapping with the range of reduced bonding strength, thereby suppressing damage to the device layer Dw.

[0083] In the wafer processing method according to the above embodiment, for example, as shown in Figure 13, the irradiation positions of the laser beam L are arranged concentrically with respect to the outer peripheral region R2. However, as shown in Figure 17, the irradiation positions of the laser beam L may be arranged spirally in the outer peripheral region R2 with respect to the rotation center of the chuck 100. In this case, when irradiating the polymerized wafer T (laser absorption layer P) corresponding to the outer peripheral region R2 with laser light L, the chuck 100 (polymerized wafer T) is rotated by the rotation mechanism 104, and the chuck 100 is moved in the negative Y direction by the moving mechanism 105. When the irradiation positions of the laser beam L are arranged in a spiral pattern in this manner, the rotation and Y-axis movement of the chuck 100 can be controlled seamlessly, thereby improving the throughput related to the irradiation of the laser beam L.

[0084] Alternatively, the irradiation positions of the laser beam L to the region corresponding to the outer peripheral region R2 may be arranged in a combination of concentric and helical configurations. Specifically, if the irradiation positions of the laser beam L are arranged spirally across the entire outer region R2, the irradiation positions of the laser beam L in the center region R2c may not be aligned circumferentially along the boundary between the central region R1 and the outer region R2. In other words, the set shape of the central region R1 may not be a constant circular shape as shown in Figure 13. Therefore, in the wafer processing apparatus 31 according to the embodiment, the irradiation positions of the laser beam L may be arranged concentrically at least in the innermost circumference of the center-side region R2c adjacent to the boundary between the central region R1 and the outer peripheral region R2, and the irradiation positions of the laser beam L radially outward from the innermost circumference may be arranged spirally. This makes it possible to control the set shape of the central region R1 to a constant value while improving the throughput of irradiation of the laser beam L to the outer peripheral region R2 and the corresponding region.

[0085] Furthermore, when the irradiation positions of the laser beam L are combined in a concentric and helical configuration, the irradiation of the laser beam L to the concentric region and the irradiation of the laser beam L to the helical region may be performed independently or continuously.

[0086] Furthermore, in the wafer processing method according to the above embodiment, for example, as shown in Figure 13, the laser light L was sequentially irradiated onto the outer peripheral region R2 from the radially outside to the radially inside. However, the irradiation of the laser light L onto the outer peripheral region R2 may also be performed from the radially inside to the radially outside. In this case, the edge-side region R2e includes the end position of laser beam L irradiation, and the center-side region R2c includes the start position of laser beam L irradiation. Even in this case, the series of wafer processing in the wafer processing apparatus 31 can be carried out in the same manner as in the above embodiment.

[0087] Next, as a modified example of the wafer processing apparatus 31 described above, an outline of the configuration of the wafer processing apparatus 500 according to the second embodiment will be explained. In the wafer processing apparatus 500, elements that are substantially the same as those in the wafer processing apparatus 31 are given the same reference numerals and detailed explanations are omitted. Also, in Figure 19, in order to avoid making the illustration complicated, the imaging mechanism 120 and the transport pad 130 provided above the chuck are not shown.

[0088] As shown in Figures 18 to 19, the wafer processing apparatus 500 has a chuck 510 that holds the polymerized wafer T on its upper surface. The chuck 510 has a substrate holding portion 100a and a light-shielding portion 510b. As shown in Figure 19, the light-shielding portion 510b is provided on the slider table 103, for example, via a support member 513, thereby being configured to move integrally with the chuck 510 in the Y-axis direction. The light-shielding portion 510b has a cover member 511 and a beam damper 512.

[0089] The cover member 511 is positioned below the lens 521 (described later) when the laser beam L from the laser irradiation unit 520 (described later) is irradiated, at least when the irradiation position of the laser beam L is separated from the chuck 510. The upper surface height of the cover member 511 is set to be approximately the same as the upper surface height of the substrate holding unit 100a, or lower than the upper surface height of the substrate holding unit 100a. The cover member 511 is made of a material that does not transmit laser beam L from the laser irradiation unit 520, such as ceramics or metal materials. Furthermore, the cover member 511 has a through hole 511a that penetrates in the thickness direction. The through hole 511a is positioned to overlap with the outer edge of the polymerized wafer T (first wafer W) held by the chuck 510, and is exposed from the polymerized wafer T (first wafer W) in a plan view. Therefore, when the laser irradiation position is away from the polymerized wafer T (first wafer W), the through hole 511a is located directly beneath the irradiation of the laser light L from the laser irradiation unit 520. The through hole 511a communicates with the internal space of the beam damper 512, meaning that the laser light L from the laser irradiation unit 520 passes through the through hole 511a of the cover member 511 and is irradiated into the interior of the beam damper 512.

[0090] The beam damper 512 has a substantially cylindrical box shape with its top surface open through a through hole 511a. As described above, the laser beam L from the laser irradiation unit 520 is irradiated into the inside of the beam damper 512. The beam damper 512 is made of a material that has beam resistance and absorbs or diffuses the laser beam L in other directions, such as a metallic material such as aluminum.

[0091] The bottom surface of the beam damper 512 has a substantially conical shape that protrudes upward, as shown as an example in Figure 20. It is desirable that the apex angle φ of this conical shape be less than 90°. As a result, in the beam damper 512, as shown in Figure 20, the laser light L that enters the interior through the through hole 511a is reflected downward or absorbed (converted into heat), thus preventing it from escaping upward again through the through hole 511a.

[0092] As described above, the beam damper 512's temperature rises due to its absorption of laser light L. Therefore, it is desirable that at least the outer surface of the beam damper 512 (e.g., the outer side or outer bottom) has a cooling surface, such as the surface area shown in Figure 20, which promotes heat dissipation (cooling of the beam damper 512). In addition, a cooling mechanism 514 (e.g., a water-cooled jacket or fan) may be provided outside the beam damper 512 to further promote heat dissipation (cooling of the beam damper 512). In one example, the cooling mechanism 514 forms a refrigerant flow path on the outside of the beam damper 512.

[0093] In the wafer processing apparatus 500, the laser light L from the laser irradiation unit 520 is received and absorbed by the beam damper 512, thereby suppressing the laser light L from reaching below the chuck 510. Furthermore, in the wafer processing apparatus 500, by receiving the laser beam L with the beam damper 512 in this manner, it is possible to suppress the upward reflection of the laser beam L which could damage internal components of the apparatus, and to suppress the generation of particles caused by the laser beam L irradiating the cover member 511.

[0094] The configuration and shape of the beam damper 512 are not limited to the examples described above. In the technology of this disclosure, a beam damper, as described above, refers to a device that receives laser light and has the function of suppressing damage to internal components of the device due to reflection of the laser light, and suppressing the generation of particles due to irradiation of the cover member with laser light.

[0095] A laser irradiation unit 520 is provided above the chuck 510. The laser irradiation unit 520 has a laser head 111 which incorporates a laser oscillator (not shown) that emits laser light, and an optical system 112. The laser irradiation unit 520 also has a lens 521 and an air supply unit 522. The lens 521 and the air supply unit 522 are configured to be able to move up and down relative to the dust collection unit 530, which will be described later.

[0096] The lens 521 focuses the laser light L emitted from the laser oscillator of the laser head 111 and irradiates the polymerized wafer T with it.

[0097] The air supply unit 522 includes an air supply passage 522a formed to surround the circumferential outer side of the lens 521. The air supply unit 522 protects the lens 521 from particles generated by laser processing by supplying dry air from the air supply source 523 to the space below the lens 521 through the air supply passage 522a.

[0098] Furthermore, as shown in Figure 20, for example, the wafer processing apparatus 500 has a dust collection unit 530 that collects particles generated by laser processing. The dust collection unit 530 is formed to surround the air supply unit 522 on the circumferential outer side. As shown in Figure 21, the dust collection unit 530 collects particles via a dust collection passage 531. The dust collection passage 531 is formed within the dust collection unit 530, and particles are collected via multiple suction ports 530b formed in the portion of the dust collection unit 530 facing the opening 530a, which will be described later. The collected particles are discharged into an exhaust port (not shown). to be sent .

[0099] Furthermore, the dust collection unit 530 has an opening 530a provided directly below the laser beam L from the laser irradiation unit 520 to allow the laser beam L to pass through. When the laser beam L from the laser irradiation unit 520 is irradiated, the opening 530a is positioned to coincide with the through hole 511a of the cover member 511 described above, that is, when the laser irradiation position is away from the superimposed wafer T (first wafer W), it is positioned to overlap with the through hole 511a in a plan view.

[0100] In the wafer processing apparatus 500 according to the second embodiment, if the beam damper 512 is placed at least directly below the lens 521 of the laser irradiation unit 520, damage to internal components of the apparatus and generation of particles caused by irradiation with laser light L can be suppressed. However, if only the beam damper 512 is placed directly below the lens 521 and the cover member 511 is not placed, the space formed on the outer side (radially outward) of the outer edge of the superimposed wafer T below the dust collection unit 530 becomes larger compared to the case where the cover member 511 is placed. In other words, the difference between the outer gap formed between the lower end of the dust collection unit 530 and the upper surface of the beam damper 512 directly below the dust collection unit 530 and the inner gap formed between the lower end of the dust collection unit 530 and the upper surface of the superimposed wafer T becomes larger compared to the difference between the outer gap and the inner gap formed between the lower end of the dust collection unit 530 and the upper surface of the cover member 511 when the cover member 511 is placed. Furthermore, when the difference between the outer gap and the inner gap becomes large in this way, the amount of suction from the inner gap side and the amount of suction from the outer gap side by the dust collection unit 530 become uneven, more specifically, the amount of suction from the outer gap side becomes larger, which may prevent proper particle collection.

[0101] In light of these points, it is desirable to provide a cover member 511 below the laser irradiation unit 520 in addition to the beam damper 512. That is, in light of the above, the cover member 511 can be said to have the role of reducing the outer gap (distance between the dust collection unit 530 and the upper surface of the cover member 511) formed between it and the dust collection unit 530, and reducing the difference between it and the inner gap (distance between the dust collection unit 530 and the upper surface of the polymerized wafer T). By reducing the difference between the outer gap and the inner gap in this way, and preferably making them approximately the same size, the amount of suction by the dust collection unit 530 becomes uniform, and particle collection can be performed efficiently. In this case, the light shielding unit 510b may be configured to be able to move up and down by, for example, a lifting mechanism (not shown). In this case, the size of the outer gap between the upper surface of the cover member 511 and the lower end of the dust collection unit 530 becomes adjustable.

[0102] The wafer processing apparatus 500 according to the second embodiment is configured as described above.

[0103] In the embodiments described above, the wafer processing method of this disclosure was applied when performing a laser lift-off to separate the first wafer W from the laser absorption layer P, but the wafer processing to which it can be applied is not limited to this.

[0104] In the semiconductor device manufacturing process, a modified layer is formed inside a silicon substrate wafer on which multiple electronic circuits and other devices are formed on the surface by irradiating it with laser light along the planar direction, and the wafer is thinned by separating it using the modified layer as a starting point. A YAG laser is used for this laser light. The laser light irradiation method of this disclosure can also be applied when forming the modified layer that serves as the starting point for wafer thinning. Furthermore, the laser light irradiation method of this disclosure can also be applied to wafer surface modification, wafer surface planarization, and wafer annealing techniques.

[0105] In the above embodiment, the explanation was given using the example of a case where the irradiation shape of the laser beam L is circular, as shown in Figure 15. However, the irradiation shape of the laser beam L is not limited to this and may be controlled to any shape (e.g., a rectangle). In one example, the irradiation shape of the laser beam L can be controlled by a diffractive optical element such as a DOE (Diffractive Optical Element).

[0106] Furthermore, in the above embodiment, the scanning of the irradiation position of the laser beam L on the polymerized wafer T was performed by moving the laser irradiation unit and the chuck in a relative horizontal direction. However, instead, the irradiated laser beam L may be configured to be scannable relative to the polymerized wafer T, for example, by using a galvanometer mirror.

[0107] In the above embodiment, the irradiation position of the laser beam L for the outer peripheral region R2 and the corresponding region was set with respect to the rotation center of the chuck 100, thereby suppressing the overlap of the irradiation range of the laser beam L in the central region R1. However, damage to the device layer Dw can be suppressed even if the irradiation range of the laser beam L overlaps, as long as it is within a range that does not damage the device layer Dw, for example, the small energy portion at the outer edge of the irradiation spot (beam diameter) of the laser beam L.

[0108] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The above embodiments may be omitted, replaced, or modified in various ways without departing from the scope and spirit of the appended claims. [Explanation of Symbols]

[0109] 31 Wafer Processing Equipment 100 Chuck 100a Substrate holding section 100b Light shielding part 104 Rotation mechanism 110 Laser irradiation area L Laser light T Polymerized wafer W First wafer S Second wafer

Claims

1. A substrate processing apparatus for processing substrates, A substrate holding portion having a substrate holding surface, A rotation mechanism that rotates the substrate on the holding surface around the rotation axis of the substrate holding part, A laser irradiation unit that irradiates the substrate on the holding surface with laser light, The substrate holding portion includes a light-shielding portion that receives the laser light from the laser irradiation portion at a position that surrounds a part of the periphery or the entire periphery, The light-shielding portion comprises a cover member having a through hole, A beam damper having an internal space formed in communication with the through hole, Circuit board processing equipment.

2. The beam damper is formed in a conical shape with its bottom surface protruding upwards. The substrate processing apparatus according to claim 1, wherein the apex angle of the conical shape is less than 90°.

3. The laser irradiation unit has an air supply unit that supplies gas, The substrate processing apparatus has a dust collection unit that collects particles, The dust collection unit is provided with an opening formed directly beneath the irradiation of the laser light, The substrate processing apparatus according to claim 1, wherein the through hole is arranged to overlap with the opening in a plan view.

4. The substrate holding portion is equipped with a plurality of pins for preventing substrates from falling, which are arranged to surround the substrate holding portion. The substrate processing apparatus according to claim 1, wherein the pin for preventing the substrate from falling is integrally formed with the light-shielding portion.

5. A substrate processing apparatus for processing substrates, A substrate holding portion having a substrate holding surface, A rotation mechanism that rotates the substrate on the holding surface around the rotation axis of the substrate holding part, A laser irradiation unit that irradiates the substrate on the holding surface with laser light, A light-shielding portion that receives the laser light from the laser irradiation portion is located at a position surrounding a part of the periphery of the substrate holding portion or the entire periphery of the periphery. A stage configured to allow the substrate holding portion to move horizontally, It comprises a plurality of pins for preventing the substrate from falling, which are arranged to surround the substrate holding portion, The pins for preventing the substrate from falling are configured to be integrated with the stage. Circuit board processing equipment.

6. A substrate processing apparatus for processing substrates, A substrate holding portion having a substrate holding surface, A rotation mechanism that rotates the substrate on the holding surface around the rotation axis of the substrate holding part, A laser irradiation unit that irradiates the substrate on the holding surface with laser light, A light-shielding portion that receives the laser light from the laser irradiation portion is located at a position surrounding a part of the periphery of the substrate holding portion or the entire periphery of the periphery. A camera for detecting the outer edge of the substrate, It comprises a control unit and, The control unit, Control to calculate the eccentricity between the center of the substrate and the rotation axis of the substrate holder based on the information detected by the camera, Control to set a central region on the substrate, where the laser beam is scanned and irradiated, and an outer peripheral region radially outside the central region, based on the rotation axis, Control to set a position considering the radius of the central region and the beam diameter of the laser light as the irradiation position of the laser light to the radially inward center region of the outer peripheral region, The control is performed to set the irradiation position of the laser beam on the radially outer edge region of the outer peripheral region, with reference to the irradiation position of the laser beam on the center region, so as to include at least the position with the largest eccentricity. Circuit board processing equipment.

7. The control unit, in setting the irradiation position of the laser beam to the edge region, A control system that calculates the distance from the center region to the substrate in the radial direction based on the beam diameter of the laser beam and the number of laser beam irradiations, The substrate processing apparatus according to claim 6, which performs control to set the position where the aforementioned distance is closest to the distance from the outer edge position of the substrate detected by the camera to the center-side region as the starting position for irradiation of the laser light to the edge-side region.

8. The control unit, The substrate processing apparatus according to claim 7, which performs control to set the irradiation position of the laser beam on the outer peripheral region with reference to the rotation axis.

9. The substrate processing apparatus according to claim 6, wherein the control unit determines that the eccentricity between the center of the substrate and the rotation axis of the substrate holder, calculated based on the information detected by the camera, exceeds a predetermined threshold, executes control to prevent the irradiation of the laser beam onto the substrate from starting.

10. The substrate processing apparatus according to claim 6, wherein the control unit determines that the eccentricity between the center of the substrate and the rotation axis of the substrate holder, calculated based on information detected by the camera, exceeds a predetermined threshold, executes control to reposition the substrate relative to the substrate holder.

11. The control unit, When the substrate is placed directly beneath the irradiation of the laser beam, control is provided to irradiate the laser beam from the laser irradiation unit, The substrate processing apparatus according to claim 6, wherein when the substrate holding portion is exposed directly beneath the irradiation of the laser light, control is performed to stop the irradiation of the laser light from the laser irradiation portion.

12. The light-shielding portion comprises a cover member having a through hole, A substrate processing apparatus according to any one of claims 5 to 11, comprising a beam damper having an internal space formed in communication with the through hole.

13. A stage configured to allow the substrate holding portion to move horizontally, The substrate holding portion is equipped with a plurality of pins for preventing substrates from falling, which are arranged to surround the substrate holding portion. The substrate processing apparatus according to any one of claims 6 to 11, wherein the pin for preventing the substrate from falling is integrated with the stage.

14. The light-shielding portion is configured to surround the substrate holding portion and be integrated with the substrate holding portion. The substrate processing apparatus according to any one of claims 1 to 11, wherein the upper surface of the light-shielding portion is positioned lower than the upper surface of the substrate holding portion.

15. The light-shielding portion is arranged around the substrate holding portion, independently of the substrate holding portion. The substrate processing apparatus according to any one of claims 1 to 11, wherein the upper surface of the light-shielding portion is positioned lower than the upper surface of the substrate holding portion.

16. A method for processing a substrate in a substrate processing apparatus, The substrate processing apparatus is The substrate holding part, A rotation mechanism that rotates the substrate on the holding surface around the rotation axis of the substrate holding part, A laser irradiation unit that irradiates the substrate on the holding surface with laser light, The substrate holding portion includes a light-shielding portion that receives the laser light from the laser irradiation portion at a position that surrounds a part of the periphery or the entire periphery, The processing method for the substrate is: To detect the eccentricity between the center of the substrate and the rotation axis of the substrate holder, A central region where the laser beam is scanned and irradiated, and an outer peripheral region radially outside the central region, are set on the substrate with respect to the rotation axis, The position, taking into account the radius of the central region and the beam diameter of the laser beam, is set as the irradiation position of the laser beam to the radially inward center region of the outer peripheral region. With reference to the irradiation position of the laser beam on the center region, the irradiation position of the laser beam on the radially outer edge region of the outer peripheral region is set to include at least the position with the largest eccentricity, A substrate processing method comprising receiving the laser light passing radially outside the substrate with the light-shielding portion.

17. The substrate processing method according to claim 16, wherein the light-shielding portion is positioned lower than the upper surface of the substrate holding portion.

18. In setting the irradiation position of the laser beam to the edge-side region, Based on the beam diameter of the laser beam and the number of laser beam irradiations, the distance from the center region to the substrate in the radial direction is calculated. The substrate processing method according to claim 16, wherein the position where the aforementioned distance is closest to the distance from the outer edge position of the substrate detected by the camera to the center-side region is set as the starting position for irradiation of the laser beam to the edge-side region.

19. A substrate processing method according to any one of claims 16 to 18, wherein if the detected eccentricity exceeds a predetermined threshold, the irradiation of the substrate with the laser light is not started.

20. When the substrate is placed directly beneath the irradiation of the laser beam, the laser beam is irradiated from the laser irradiation unit. The substrate processing method according to any one of claims 16 to 18, wherein the irradiation of the laser beam from the laser irradiation unit is stopped when the substrate holding unit is exposed directly beneath the irradiation of the laser beam.

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