Program and board processing apparatus

Abstract

The present invention provides a program and a substrate processing apparatus for appropriately performing peeling in a polymerized substrate. [Solution] A polymerized substrate is formed by laminating a first substrate W, an interface layer including a laser absorption layer P, and a second substrate S. The substrate processing method involves rotating the polymerized substrate, which has an outer peripheral region Z0 including an unbonded region between the first substrate and the second substrate, and a first inner peripheral region Z1 to a third inner peripheral region located in the bonding region between the first substrate and the second substrate, and irradiating the polymerized substrate with laser light moving radially from a laser irradiation unit, causing delamination E1 and E3 at the interface between the first substrate and the laser absorption layer or the interface layer and the laser absorption layer, and after irradiating the inner peripheral region with laser light, irradiating the outer peripheral region with laser light moving radially from the inside to the outside.

Description

Technical Field

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

Background Art

[0002] Patent Document 1 discloses transferring a semiconductor element to a transfer destination substrate in a semiconductor substrate on which a peeling oxide film and a semiconductor element are formed on the surface. The method described in Patent Document 1 includes a step of locally heating the peeling oxide film by irradiating light from the back surface of the semiconductor substrate, and a step of causing peeling in the peeling oxide film and / or at the interface between the peeling oxide film and the semiconductor substrate to transfer the semiconductor element to the transfer destination substrate.

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 appropriately peels the first substrate and the laser absorption layer in a polymerized substrate in which a laser absorption layer is formed at the interface between the first substrate and the second substrate.

Means for Solving the Problems

[0005] One aspect of the present disclosure is a program that operates on a computer of a control device that controls a substrate processing apparatus to cause the substrate processing apparatus to execute a substrate processing method for processing a polymerized substrate formed by laminating a first substrate, an interface layer including at least a laser absorption layer, and a second substrate, wherein the substrate processing apparatus comprises a substrate holding unit for holding the polymerized substrate, a laser irradiation unit for irradiating the polymerized substrate held by the substrate holding unit with laser light, a moving mechanism for moving the substrate holding unit and the laser irradiation unit in a relative horizontal direction, a rotating mechanism for rotating the substrate holding unit, and the control device for storing the program, wherein the substrate processing method includes an outer peripheral region in the polymerized substrate that includes an unbonded region between the first substrate and the second substrate, and the outer peripheral region The process includes: holding a polymer substrate in the substrate holding section, wherein the polymer substrate has an inner peripheral region located radially inside the region and in the bonding region of the first substrate and the second substrate; rotating the polymer substrate held in the substrate holding section and irradiating the polymer substrate with laser light from the laser irradiation section while moving it radially, thereby causing delamination at the interface between the first substrate and the laser absorption layer, or at the interface between the interface layer and the laser absorption layer; irradiating the inner peripheral region with the laser light; and irradiating the outer peripheral region with the laser light while moving it radially from the inside to the outside, wherein irradiating the outer peripheral region with the laser light while moving it radially from the inside to the outside is performed after irradiating the inner peripheral region with the laser light. [Effects of the Invention]

[0006] According to this disclosure, in a polymerized substrate in which a laser absorption layer is formed at the interface between a first substrate and a second substrate, the first substrate and the laser absorption layer can be appropriately separated. [Brief explanation of the drawing]

[0007] [Figure 1] This is a side view showing an example of the configuration of a polymerized wafer according to an embodiment. [Figure 2] This is a plan view showing the schematic configuration of the wafer processing system. [Figure 3] This is a plan view showing the schematic configuration of the laser irradiation device. [Figure 4] This is a side view showing a schematic configuration of the laser irradiation device. [Figure 5] This is a side view showing the operation of the separation device. [Figure 6] This is an explanatory diagram showing the state of a polymerized wafer when irradiated with laser light. [Figure 7] This is a flowchart showing the main steps in wafer processing in a wafer processing system. [Figure 8] This is an explanatory diagram showing how heat diffuses in a polymerized wafer. [Figure 9] This is an explanatory diagram showing the state of a polymerized wafer when irradiated with laser light. [Figure 10] This is an explanatory diagram showing the delamination process between the first wafer and the laser absorption layer. [Figure 11] This is an explanatory diagram showing the delamination process between the first wafer and the laser absorption layer. [Figure 12] This is a flowchart showing the main steps in wafer processing in a wafer processing system. [Figure 13] This is an explanatory diagram showing the regions of the polymerization wafer, the rotation speed of the chuck in each region, and the frequency of the laser light in each region. [Figure 14] This is a side view showing the outer periphery region and the first inner periphery region. [Figure 15] This is an explanatory diagram showing the state of a polymerized wafer when laser light is irradiated onto its outer region. [Figure 16] This is an explanatory diagram showing the state of a polymerized wafer when laser light is irradiated onto its outer region. [Figure 17] This is an explanatory diagram showing the state of a polymerized wafer when laser light is irradiated onto its outer region. [Figure 18] This is an explanatory diagram showing the state of a polymerized wafer when laser light is irradiated onto the second inner region and the first inner region. [Figure 19] This is an explanatory diagram showing the state of a polymerized wafer when laser light is irradiated into the first inner region. [Figure 20]It is an explanatory diagram showing a state of a polymerized wafer irradiated with laser light in a central region. [Figure 21] It is an explanatory diagram showing a state of a polymerized wafer irradiated with laser light in another embodiment. [Figure 22] It is an explanatory diagram showing a state of a polymerized wafer irradiated with laser light in another embodiment. [Figure 23] It is an explanatory diagram showing a state of a polymerized wafer irradiated with laser light in another embodiment. [Figure 24] It is an explanatory diagram showing a state of peeling between a peeling promotion layer and a laser absorption layer. [Figure 25] It is a flowchart showing main steps of wafer processing according to another embodiment.

Mode for Carrying Out the Invention

[0008] In a manufacturing process of a semiconductor device, in a polymerized wafer in which two semiconductor substrates (hereinafter referred to as "wafers") are bonded, a device layer formed on the surface of a first wafer is transferred to a second wafer. Transfer of this device layer to the second wafer is performed by irradiating laser light to a laser absorption layer formed between the first wafer and the device layer and peeling the first wafer and the laser absorption layer. Specifically, for example, while rotating the polymerized wafer and moving the laser light from the radially outer side to the inner side, the laser light is pulsed onto the laser absorption layer.

[0009] Here, the peripheral portion of the polymerized wafer has a chamfered portion (bevel portion), and such a peripheral portion is not bonded. That is, the outer peripheral region of the polymerized wafer includes an unbonded region, and at the boundary between the unbonded region and the bonded region, the bonding strength of the interface between the first wafer (including the device layer) and the second wafer is low. In such a case, when laser light is irradiated to the outer peripheral region, peeling occurs at the interface between the first wafer and the second wafer where the bonding strength is low in the outer peripheral region.

[0010] In this state, if laser light is irradiated from the radially outside to the inside in the outer region, delamination tends to progress in the bonding region adjacent to the radially inside of the unbonded region, with the interface between the delaminated first wafer and the second wafer as the leading edge. In other words, in the bonding region of the outer region, delamination does not occur at the desired interface, which is the interface between the first wafer and the laser absorption layer. As a result, it may not be possible to transfer the device layer of the first wafer to the second wafer.

[0011] The technology described herein provides a method for appropriately separating a laser absorption layer from a first substrate in a polymerized substrate in which a laser absorption layer is formed at the interface between a first substrate and a second substrate. Hereinafter, a wafer processing system equipped with a laser irradiation device as a substrate processing apparatus according to this embodiment, and a wafer processing method as a substrate processing method, will be described with reference to the drawings. In this specification and the drawings, elements having substantially the same functional configuration are denoted by the same reference numerals to avoid redundant explanations.

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

[0013] The first wafer W, which serves as the first substrate, is a semiconductor wafer such as a silicon substrate. In one embodiment, the first wafer W has a substantially disc shape. A laminated film is formed on the surface Wa of the first wafer W, which consists of multiple films stacked on top of each other. The laminated film includes, in order from the surface Wa side, a laser absorption layer P, a device layer Dw, and a surface film Fw. The device layer Dw includes multiple devices. Examples of the surface film Fw include an oxide film (THOX film, SiO2 film, TEOS film), a SiC film, a SiCN film, or an adhesive. The first wafer W is joined to the second wafer S via this surface film Fw. Note that the device layer Dw and surface film Fw may not be 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, which will be described later, is transferred to the first wafer W side.

[0014] The laser absorption layer P absorbs the laser light irradiated from the laser irradiation unit 110, as will be described later. For example, an oxide film (SiO2 film, TEOS film) can be used for the laser absorption layer P, but it is not particularly limited as long as it absorbs laser light. The laser absorption layer P is formed, for example, outside the wafer processing system 1, by a CVD (Chemical Vapor Deposition) process. The composition of the oxide film (SiO2 film, TEOS film) as the laser absorption layer P can be arbitrarily changed depending on the type and mixing ratio of the processing gas used in the CVD process.

[0015] The second wafer S, which serves as the second substrate, is a semiconductor wafer such as a silicon substrate. A multilayer film is formed on the surface Sa of the second wafer S. The multilayer film has a device layer Ds and a surface film Fs in that order from the surface Sa side. The device layer Ds and 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 there are cases where the device layer Ds and surface film Fs are not formed on the surface Sa.

[0016] In the technology of this disclosure, the laminated film formed at the interface between the first wafer W and the second wafer S, specifically the laser absorption layer P, device layers Dw and Ds, and surface films Fw and Fs, may be collectively referred to as the "interface layer." In the technology of this disclosure, the interface layer includes at least the laser absorption layer P. The type of laminated film formed at the interface between the first wafer W and the second wafer S is not limited to the example shown in Figure 1. For example, the laminated film may include a "peeling-promoting film," described later, for properly separating the first wafer W from the laser absorption layer P. In this case, the interface layer described above includes the peeling-promoting film.

[0017] 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 laser irradiation device 31 and the separation device 32, which will be described later, of the processing block 30 are located on the negative X-axis side of the transport block 20, while the first cleaning device 33 and the second cleaning device 34, which will be described later, are located on the positive X-axis side of the transport block 20.

[0018] 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, the cassette mounting table 11 can accommodate multiple cassettes, for example, three cassettes Ct, Cw, and Cs, in a single row along the X-axis. The number of cassettes Ct, Cw, and Cs placed on the cassette mounting table 11 is not limited to this embodiment and can be determined arbitrarily.

[0019] The transport block 20 is provided with a wafer transport device 22 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 on the cassette mounting table 11, the laser irradiation device 31, the separation device 32, the first cleaning device 33, and the second cleaning device 34.

[0020] The processing block 30 includes a laser irradiation device 31, a separation device 32, a first cleaning device 33, and a second cleaning device 34. In one example, the laser irradiation device 31 and the separation device 32 are stacked on the negative X-axis side of the transport block 20. The first cleaning device 33 and the second cleaning device 34 are stacked on the positive X-axis side of the transport block 20. The number and arrangement of the laser irradiation device 31, the separation device 32, the first cleaning device 33, and the second cleaning device 34 are not limited to these examples.

[0021] The laser irradiation device 31 irradiates laser light onto the inside of the polymerized wafer T, more specifically onto the laser absorption layer P formed on the surface Wa of the first wafer W, thereby reducing the bonding strength at the interface between the first wafer W and the laser absorption layer P.

[0022] As shown in Figure 3, a transfer position A1 and a processing position A2 are set inside the laser irradiation device 31. Transfer position A1 is a position from which the polymerized wafer T can be transferred from the transport arm 23 to the chuck 100 (described later), and is also a position from which the polymerized wafer T (laser absorption layer P) can be imaged by the camera 120 (described later). Processing position A2 is a position from which laser light can be irradiated onto the polymerized wafer T (laser absorption layer P) from the laser irradiation unit 110 (described later).

[0023] As shown in Figures 3 and 4, the laser irradiation device 31 has a chuck 100 as a substrate holder that holds the polymerized wafer T on its upper surface. The chuck 100 has a holding surface for the polymerized wafer T on its upper surface and holds the entire surface Sb of the back surface of the second wafer S, or a part of the radially inner surface Sb, by suction. The chuck 100 is, for example, an electrostatic chuck (ESC) or a vacuum chuck. The chuck 100 is provided with a lifting pin (not shown) for supporting and raising / lowering the polymerized wafer T from below. The lifting pin is inserted through a through hole (not shown) formed through the chuck 100 and is configured to be able to move up and down.

[0024] The chuck 100 is supported by the slider table 102 via an air bearing 101. A rotating mechanism 103 is provided on the underside of the slider table 102. The rotating mechanism 103 incorporates, for example, a motor as a drive source. The chuck 100 is configured to rotate around the θ axis (vertical axis) via the air bearing 101 through the rotating mechanism 103. The slider table 102 is configured to move between the above-mentioned transfer position A1 and processing position A2 along a rail 106 that extends in the Y-axis direction and is provided on the base 105, by a moving mechanism 104 provided on its underside. The drive source for the moving mechanism 104 is not particularly limited, but for example, a linear motor can be used.

[0025] A laser irradiation unit 110 is provided above the chuck 100 at processing position A2. The laser irradiation unit 110 includes a laser head 111, an optical system 112, and a lens 113. The laser irradiation unit 110 can scan the laser beam. In the following description, scanning the laser beam means moving the laser beam emitted from the lens 113 of the laser irradiation unit 110 relative to the laser absorption layer P.

[0026] The laser head 111 has a laser oscillator (not shown) that emits laser light in a pulsed manner. This laser light is a so-called pulsed laser. In this embodiment, the laser light 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.

[0027] The optical system 112 includes an optical element (not shown) that controls the intensity and position of the laser beam, an attenuator (not shown) that attenuates the laser beam to adjust the output, and a laser scanning unit (not shown) that scans the laser beam. For example, a rotary wedge scanner or a galvanometer scanner can be used as the laser scanning unit. The optical system 112 may also be configured to control the branching of the laser beam.

[0028] The lens 113 irradiates the polymerized wafer T held in the chuck 100 with laser light. The laser light 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 horizontally by a moving mechanism (not shown) or to move vertically by a lifting mechanism (not shown).

[0029] Furthermore, a camera 120 is provided above the chuck 100 at the transfer position A1. The camera 120 has one or more cameras selected from macro cameras, micro cameras, etc. The camera 120 may be configured to move horizontally by a moving mechanism (not shown) or to move vertically up and down by a lifting mechanism (not shown).

[0030] Camera 120 images the polymerized wafer T held in the chuck 100. Camera 120 is equipped with, for example, a coaxial lens, emits infrared light (IR), and also receives reflected light from the object. The image data captured by camera 120 is output to the control device 40, which will be described later.

[0031] As will be described later, the wafer processing system 1 has a control device 40, and this control device 40 is provided in the laser irradiation device 31 and also functions as a control unit that controls the laser irradiation device 31.

[0032] The separation device 32, acting as a separation unit, peels the first wafer W from the second wafer S (polymerized wafer T) using the interface between the first wafer W and the laser absorption layer P, which is a delamination portion whose bonding strength has been reduced by the laser irradiation device 31, as a starting point.

[0033] In one example, as shown in Figure 5, the separation device 32 includes a suction chuck 200 that adsorbs and holds the back surface Sb of the second wafer S from below, and a suction pad 210 that adsorbs and holds the back surface Wb of the first wafer W from above. In the separation device 32, as shown in Figure 5, with the suction chuck 200 adsorbing and holding the second wafer S and the suction pad 210 adsorbing and holding the first wafer W, the suction pad 210 is raised to peel the first wafer W from the laser absorption layer P.

[0034] The configuration of the separation device 32 is not limited to this; any configuration is possible as long as the first wafer W can be separated from the second wafer S.

[0035] The first cleaning apparatus 33 cleans the surface Sa side of the second wafer S that has been separated by peeling in the separation apparatus 32. For example, a brush is brought into contact with the laser absorption layer P on the surface Sa side of the second wafer S to clean the laser absorption layer P. A pressurized cleaning solution may be used to clean the second wafer S. The first cleaning apparatus 33 may also have a configuration to clean the back surface Sb of the second wafer S along with the surface Sa side.

[0036] The second cleaning apparatus 34 cleans the surface Wa side of the first wafer W that has been separated by peeling in the separation apparatus 32. For example, a brush is brought into contact with the surface Wa of the first wafer W to clean the surface Wa. A pressurized cleaning solution may be used to clean the first wafer W. The second cleaning apparatus 34 may also be configured to clean the back surface Wb of the first wafer W along with the surface Wa side.

[0037] In this embodiment, as described above, the first cleaning apparatus 33 for cleaning the second wafer S and the second cleaning apparatus 34 for cleaning the first wafer W are arranged independently. However, the cleaning of the first wafer W and the cleaning of the second wafer S may be performed using the same cleaning apparatus. In this case, the cleaning of the first wafer W and the second wafer S may be performed simultaneously or independently.

[0038] In this embodiment, the first wafer W was separated from the second wafer S using the separation device 32, but this separation may also be performed inside the laser irradiation device 31. For example, a liftable transport pad (not shown) is provided at the transfer position A1 of the laser irradiation device 31. Then, with the chuck 100 adsorbing and holding the second wafer S, the first wafer W is adsorbed and held by the transport pad, and the transport pad is further raised to separate the first wafer W from the second wafer S.

[0039] 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.

[0040] Next, a wafer processing procedure performed using the wafer processing system 1 configured as described above will be explained. In this embodiment, a first wafer W and a 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.

[0041] First, a cassette Ct containing multiple polymerized wafers T is placed on the cassette mounting table 11 of the loading / unloading block 10.

[0042] Next, the polymerized wafer T is removed from the cassette Ct by the wafer transport device 22 and transported to the laser irradiation device 31. In the laser irradiation device 31, the polymerized wafer T is transferred from the transport arm 23 to the chuck 100 located at the transfer position A1, and the back surface Sb of the second wafer S is held by the chuck 100. Subsequently, the chuck 100 is moved to the processing position A2 by the moving mechanism 104.

[0043] Next, as shown in Figure 6, the laser irradiation unit 110 focuses on the laser absorption layer P, more specifically the interface between the first wafer W and the laser absorption layer P, and pulses laser light L (CO2 laser light) is irradiated onto this interface. At this time, the laser light L passes through the first wafer W from the back surface Wb side and is absorbed by the laser absorption layer P. This laser light L reduces the bonding strength between the first wafer W and the laser absorption layer P. In this embodiment, "reduced bonding strength" means a state in which the bonding strength is reduced at least compared to before irradiation with the laser light L, and includes delamination between the first wafer W and the laser absorption layer P. Further details regarding the mechanism by which the bonding strength between the first wafer W and the laser absorption layer P decreases due to irradiation with laser light L will be described later.

[0044] When irradiating the laser absorption layer P with laser light L at processing position A2, first, the polymerized wafer T (first wafer W) is imaged by the camera 120. The image data captured by the camera 120 is output to the control device 40. Based on the image data, the control device 40 determines the starting position for irradiating the laser light L onto the laser absorption layer P.

[0045] Next, at processing position A2, laser light L is irradiated from the laser irradiation unit 110 onto the entire surface of the laser absorption layer P in a plan view at desired intervals, thereby reducing the bonding strength across the entire interface between the first wafer W and the laser absorption layer P. Details of this method of irradiating the laser absorption layer P with laser light L will be described later.

[0046] When the entire surface of the laser absorption layer P is irradiated with laser light L and the bonding strength between the first wafer W and the entire surface of the laser absorption layer P is reduced, the chuck 100 (polymerized wafer T) is then moved to the transfer position A1 by the moving mechanism 104.

[0047] Next, the polymerized wafer T on the chuck 100 is transferred to the transfer arm 23 of the wafer transfer device 22 and transported to the separation device 32. In the separation device 32, as shown in Figure 5(a), the back surface Sb of the second wafer S is adsorbed and held by the suction chuck 200, and the back surface Wb of the first wafer W is further adsorbed and held by the suction pad 210. Then, as shown in Figure 5(b), with the suction pad 210 adsorbing and holding the first wafer W, the suction pad 210 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 first wafer W and the laser absorption layer P is reduced by irradiation with laser light L, so the first wafer W can be separated from the laser absorption layer P without applying a large load.

[0048] The separated first wafer W is transferred from the suction pad 210 to the transport arm 23 of the wafer transport device 22 and then transported to the second cleaning device 34. At this time, the first wafer W discharged from the separation device 32 may be inverted, for example, by an inversion device (not shown) or the operation of the suction pad 210, so that the front surface Wa faces upward, before being transported to the second cleaning device 34.

[0049] In the second cleaning device 34, the surface Wa of the first wafer W, which is the side separated by the separation device 32, is cleaned. The second cleaning device 34 may also clean the back surface Wb along with the surface Wa. Alternatively, separate cleaning units may be provided for cleaning the surface Wa and the back surface Wb, respectively. Afterward, the first wafer W, having been cleaned by the second cleaning device 34, is transported by the wafer transport device 22 to the cassette Cw on the cassette tray 11.

[0050] Meanwhile, the second wafer S, held by the suction chuck 200, is transferred to the transport arm 23 and transported to the first cleaning device 33. In the first cleaning device 33, the surface Sa side of the second wafer S, specifically the surface of the laser absorption layer P, which is the side separated by the separation device 32, is cleaned. In addition, the back surface Sb of the second wafer S may also be cleaned in the first cleaning device 33 along with the surface of the laser absorption layer P. 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. After cleaning by the first cleaning device 33, the second wafer S is transported by the wafer transport device 22 to the cassette Cs on the cassette mounting table 11.

[0051] Thus, the series of wafer processing operations in wafer processing system 1 is completed.

[0052] Next, we will explain in detail the mechanism by which the bonding strength between the first wafer W and the laser absorption layer P decreases due to irradiation with laser light L at processing position A2 of the laser irradiation device 31 described above.

[0053] As described above, at processing position A2 of the laser irradiation device 31, laser light L is irradiated onto the polymerized wafer T held in the chuck 100 from the back surface Wb side of the first wafer W (step St11 in Figure 7). The laser light L output from the lens 113 of the laser irradiation unit 110 is absorbed by the laser absorption layer P after passing through the silicon (first wafer W) as shown in Figure 6 (step St12 in Figure 7).

[0054] The laser light L absorbed by the laser absorption layer P is converted into heat according to its energy distribution (step St13 in Figure 7). In other words, the absorption of laser light L causes the temperature of the laser absorption layer P to rise. The temperature of the laser absorption layer P is highest in the region directly beneath the irradiation of the laser light L. As shown in Figure 8, most of the heat (Ht in the figure) generated in the laser absorption layer P due to the absorption of laser light L diffuses to the first wafer W side (step St14 in Figure 7). In other words, the temperature of the interface between the laser absorption layer P and the first wafer W (silicon) rises due to the thermal diffusion from the laser absorption layer P.

[0055] When the heat generated in the laser absorption layer P diffuses to the first wafer W, the effect of this heat, i.e., the rise in the interface temperature between the laser absorption layer P and the first wafer W, causes the first wafer W in the area irradiated by the laser light L to expand locally according to its temperature distribution (plastic deformation into a downward convex shape relative to the laser absorption layer P side) as shown in Figure 9 (step St15 in Figure 7). Hereafter, the region affected by the heat generated by the irradiation of laser light L may be referred to as the "irradiation region R" of laser light L. In other words, the first wafer W expands locally in the irradiation region R of laser light L.

[0056] Here, as the first wafer W expands, the laser absorption layer P is pressed from above (on the first wafer W side) as a result of the expansion of the first wafer W, and as a result, compressive stress σ1 is generated in the laser absorption layer P at the irradiation position of the laser beam L, as shown in Figure 9. The generated compressive stress σ1 acts in a direction that separates the first wafer W and the laser absorption layer P (downward in the figure, on the laser absorption layer P side), as shown in Figure 9, and generates delamination stress σ2. In other words, in the irradiation region R of the laser beam L, silicon (the first wafer W) expands in the region directly beneath the irradiation of the laser beam L (the central part of the irradiation region R), generating a compressive stress σ1. Simultaneously, at the edge Re of the irradiation region R (see Figure 9), a peeling stress σ2, which is a stress in the peeling direction caused by the compressive stress σ1, is generated. This peeling stress σ2 is a tensile stress that occurs at the edge Re of the irradiation region R.

[0057] The generated compressive stress σ1 and peeling stress σ2 are accumulated inside the laser absorption layer P. At this time, at the edge Re of the irradiation region R, the peeling stress σ2 generated in multiple irradiation regions R act synergistically (overlappingly).

[0058] Then, when the total accumulated amount (synergistic amount) of peeling stress σ2 at the edge Re of the irradiation region R exceeds the adhesion force Σ between the first wafer W and the laser absorption layer P per unit area at the edge Re (n × σ2 > Σ (where n is a natural number and the number of laser beam L irradiations)), peeling occurs at the interface between the first wafer W and the laser absorption layer P at the edge Re of the irradiation region R, as shown in Figure 10. As a result, the bonding strength between the laser absorption layer P and the first wafer W decreases (step St16 in Figure 7).

[0059] Furthermore, the stress σ (compressive stress σ1 and peeling stress σ2) accumulated inside the laser absorption layer P is released by the delamination of the first wafer W and the laser absorption layer P.

[0060] Then, at processing position A2 of the laser irradiation device 31, as shown in Figure 11, delamination is caused across the entire interface between the first wafer W and the laser absorption layer P in a plan view. In other words, the delamination that occurred at the edge Re of the irradiation region R is connected across the entire interface between the first wafer W and the laser absorption layer P, thereby reducing the bonding strength across the entire surface of the first wafer W and the laser absorption layer P. This allows the separation device 32 to properly separate the first wafer W and the laser absorption layer P (step St17 in Figure 7). Ideally, in the polymerized wafer T after irradiation with laser light L at processing position A2, delamination from the laser absorption layer P should occur across the entire surface of the first wafer W. In other words, after delamination occurs at the edge Re of the irradiation region R, the first wafer W and the laser absorption layer P should also be separated in the central part of the irradiation region R, including the region directly below the irradiation, due to the delamination stress σ2. However, as shown in Figure 10, in the central part of the irradiation region R (the region directly below the irradiation of laser light L), the first wafer W and the laser absorption layer P may remain connected (not delaminated) even after delamination occurs at the edge Re of the irradiation region R. Therefore, in the wafer processing system 1 according to the technology of this disclosure, it is preferable to provide a separation device 32 in the polymerized wafer T after irradiation with laser light L to reliably separate the first wafer W from the polymerized wafer T (laser absorption layer P), and to include a step in which the separation device 32 separates the first wafer W from the polymerized wafer T.

[0061] Here, when the separation of the first wafer W from the polymerized wafer T is performed by the separation device 32, if the polymerized wafer T is transported to the separation device 32 in the ideal state described above, that is, when delamination from the laser absorption layer P has occurred across the entire surface of the first wafer W, there is a risk that the first wafer W may fall from the second wafer S due to the inertial force etc. associated with this transport. Furthermore, if delamination from the laser absorption layer P occurs across the entire surface of the first wafer W in this manner, even if it is not necessary to transport the polymerized wafer T to the separation device 32 after irradiation with laser light L, there is a risk that the first wafer W may fly off the second wafer S due to centrifugal force caused by the rotation of the chuck 100 while the laser light L is irradiated onto the laser absorption layer P at processing position A2.

[0062] In view of these points, in order to suppress the scattering and falling of the first wafer W during irradiation of the laser light L to the laser absorption layer P and during transport of the polymerized wafer T, it is preferable to control the irradiation conditions of the laser light L (irradiation position, output, etc.) at the processing position A2 so as to maintain a state in which at least a part of the interface between the first wafer W and the laser absorption layer P remains connected (not peeled off). As a result, the first wafer W is completely separated from the laser absorption layer P during irradiation with laser light L or during transport to the separation device 32, and scattering and falling from the second wafer S is suppressed.

[0063] The reduction in bonding strength between the first wafer W and the laser absorption layer P at processing position A2 of the laser irradiation device 31 is achieved as described above. In other words, in this embodiment, the laser irradiation device 31 expands the first wafer W due to the heat generated by irradiation with laser light L, generating compressive stress σ1 in the laser absorption layer P. This generates peeling stress σ2 in the peeling direction at the interface between the first wafer W and the laser absorption layer P, causing delamination at the interface between the first wafer W and the laser absorption layer P, thereby reducing the bonding strength.

[0064] In the above embodiment, as shown in Figure 9, the laser absorption layer P was irradiated with laser light L multiple times, and when the total amount of accumulated peeling stress σ2 caused by this irradiation exceeded the adhesion force Σ between the first wafer W and the laser absorption layer P, peeling occurred at the edge Re of the irradiated area R. However, the number of times laser light L is irradiated before such peeling occurs is not limited to multiple times. For example, if the delamination stress σ2 generated by a single laser beam L irradiation exceeds the adhesion force Σ at the edge Re, then delamination may occur at the interface between the first wafer W and the laser absorption layer P at the edge Re of the irradiated region R due to the irradiation of the single laser beam L.

[0065] Next, we will explain in detail the method of irradiating the laser absorption layer P with laser light L at processing position A2 of the laser irradiation device 31 described above.

[0066] First, as shown in Figure 13, the regions of the polymerized wafer T (laser absorption layer P) in a plan view are set to the outer peripheral region Z0, the first inner peripheral region Z1, the second inner peripheral region Z2, and the central region Z3 (step St20 in Figure 12). Specifically, for example, an operator sets the outer peripheral region Z0, the first inner peripheral region Z1, the second inner peripheral region Z2, and the central region Z3, and these regions are stored in the control device 40. The outer peripheral region Z0, the first inner peripheral region Z1, the second inner peripheral region Z2, and the central region Z3 are arranged in this order from the radial outside to the inside. Furthermore, the outer peripheral region Z0, the first inner peripheral region Z1, and the second inner peripheral region Z2 are arranged concentrically around the polymerized wafer T, and the central region Z3 is arranged concentrically around the polymerized wafer T.

[0067] As shown in Figures 13 and 14, the outer peripheral region Z0 is the peripheral region of the polymerized wafer T, and includes an unbonded region Q where the first wafer W (surface film Fw) and the second wafer S (surface film Fs) are not bonded, and a bonded region B radially inward from the unbonded region Q. The unbonded region Q includes a beveled portion where the peripheral edge has been chamfered. The unbonded region Q also includes a region where the first wafer W and the second wafer S are not bonded due to, for example, misalignment of the bonding position or other factors.

[0068] The first inner region Z1, the second inner region Z2, and the central region Z3 are each regions located in the bonding region B of the first wafer W and the second wafer S.

[0069] In this embodiment, the polymerized wafer T is rotated, and the laser beam L is moved radially while the laser beam L is irradiated in a pulsed manner. In this case, in order to uniformly separate the first wafer W and the laser absorption layer P across the wafer surface, it is preferable to keep the interval between irradiations of the laser beam L, i.e., the pulse interval, constant. To keep the irradiation interval of the laser beam L constant, for example, the rotation speed of the polymerized wafer T is increased as the laser beam L moves from the radial outside to the inside. When the rotation speed of the polymerized wafer T reaches its upper limit, then, for example, the frequency of the pulsed irradiation of the laser beam L is decreased as the laser beam L moves from the radial outside to the inside. When the rotation speed of the polymerized wafer T reaches its upper limit and the frequency of the laser beam reaches its lower limit, for example, the irradiation interval of the laser beam decreases as the laser beam L moves from the radial outside to the inside, and the laser beam L may overlap in the central region of the polymerized wafer T.

[0070] Therefore, in this embodiment, the polymerized wafer T is rotated while the laser beam L is irradiated in the outer peripheral region Z0, the first inner peripheral region Z1, and the second inner peripheral region Z2. On the other hand, in the central region Z3, the rotation of the polymerized wafer T is stopped while the laser beam L is scanned.

[0071] In the outer peripheral region Z0 and the first inner peripheral region Z1, the frequency of the laser beam L is kept constant, while the rotation speed of the polymerized wafer T is varied in accordance with the radial movement of the laser beam L, thereby irradiating the wafer with the laser beam L in a pulsed manner. Specifically, when the laser beam L moves from the radial outside to the inside, the rotation speed of the polymerized wafer T is increased, and when the laser beam L moves from the radial inside to the outside, the rotation speed of the polymerized wafer T is decreased.

[0072] In the second inner region Z2, while keeping the rotation speed of the polymerized wafer T constant, the frequency of the laser beam L is varied as the laser beam L moves radially, thereby irradiating the wafer with pulsed laser beam L. Specifically, the frequency of the laser beam L is decreased when it moves radially from the outside to the inside, and increased when it moves radially from the inside to the outside.

[0073] The boundary between the first inner region Z1 and the second inner region Z2 is set to the position where the rotation speed of the polymerized wafer T reaches its upper limit. The boundary between the second inner region Z2 and the central region Z3 is set to the position where the frequency of the laser light L reaches its lower limit.

[0074] Next, the laser absorption layer P is irradiated with laser light L. At this time, the processing conditions for the laser treatment are changed for each region Z0 to Z3. In this embodiment, the irradiation of the laser light L to the outer peripheral region Z0 (step St21 in Figure 12), the irradiation of the laser light L to the second inner peripheral region Z2 (step St22 in Figure 12), the irradiation of the laser light L to the first inner peripheral region Z1 (step St23 in Figure 12), and the irradiation of the laser light L to the central region Z3 (step St24 in Figure 12) are performed in this order.

[0075] In step St21, in the outer peripheral region Z0, as shown in Figure 15, the chuck 100 (the polymerized wafer T held in the chuck 100) is rotated counterclockwise by the rotation mechanism 103, and the chuck 100 is moved in the positive Y-axis direction by the movement mechanism 104 while the laser beam L is irradiated in a pulsed manner. At this time, the laser beam L is fixed without scanning. As a result, in the outer peripheral region Z0, the laser beam L is irradiated in a spiral pattern from the radially inner to the outer side. Furthermore, due to the delamination mechanism between the first wafer W and the laser absorption layer P caused by the irradiation of the laser beam L as described above, delamination occurs at the interface between the first wafer W and the laser absorption layer P in the outer peripheral region Z0, as shown in Figure 16.

[0076] Furthermore, since the outer peripheral region Z0 includes the unbonded region Q, the bonding strength between the first wafer W and the second wafer S, i.e., the bonding strength between the surface film Fw and the surface film Fs, is low at the boundary between the unbonded region Q and the bonded region B. In such a case, when laser light L is irradiated onto the outer peripheral region Z0, as shown in Figure 17, if the delamination stress σ2 does not exceed the adhesion force Σ between the first wafer W and the laser absorption layer P in the outer peripheral region Z0, delamination will not occur between the first wafer W and the laser absorption layer P. Then, the convex shape of the interface between the first wafer W and the laser absorption layer P is transmitted to the surface film Fw, and stress acts on the interface between the surface film Fw and the surface film Fs. Due to this stress, delamination may occur at the interface between the surface film Fw and the surface film Fs, where the bonding strength is low, at the boundary between the unbonded region Q and the bonded region B. In this state, when the laser beam L is moved from the radial outside to the inside in the outer peripheral region Z0, delamination is more likely to proceed in the bonding region B adjacent to the radial inside of the unbonded region Q, with the interface between the delaminated surface film Fw and the surface film Fs as the leading edge. In other words, in the bonding region B of the outer peripheral region Z0, delamination may not occur at the desired interface between the first wafer W and the laser absorption layer P.

[0077] Therefore, in this embodiment, laser light L is irradiated from the radially inner to the outer region Z0. As a result, delamination E1 occurs at the interface between the first wafer W and the laser absorption layer P in the bonding region B, as shown in Figure 16. At this time, stress σ is generated in each irradiation region R so that delamination E1 occurs from the center to the edge Re. In order to generate such a large stress σ, for example, the frequency of the laser light L may be increased (the pitch of the laser light L may be shortened), or the irradiation intensity of the laser light L may be increased. In addition, at the boundary between the bonding region B and the unbonded region Q, delamination E2 occurs that extends from the interface between the first wafer W and the laser absorption layer P toward the interface between the surface film Fw and the surface film Fs because the bonding strength at the interface between the surface film Fw and the surface film Fs is low. Even if delamination E2 occurs, the device layer Dw radially outside the delamination E2 is not a device that will be commercialized, so it has no effect.

[0078] Next, in step St22, in the second inner circumference region Z2, as shown in Figure 18, the chuck 100 is rotated counterclockwise by the rotation mechanism 103, and the chuck 100 is moved in the positive Y-axis direction by the movement mechanism 104, while the laser beam L is irradiated in a pulsed manner. At this time, the laser beam L is fixed without scanning. As a result, in the second inner circumference region Z2, the laser beam L is irradiated in a spiral manner from the radially inner side to the outer side. Also, in the second inner circumference region Z2, delamination occurs at the interface between the first wafer W and the laser absorption layer P, as shown in Figure 11.

[0079] Next, in step St23, the laser beam L is irradiated onto the first inner circumference region Z1, as well as the second inner circumference region Z2 in step St22, as shown in Figure 18. That is, the chuck 100 is rotated counterclockwise by the rotation mechanism 103, and the chuck 100 is moved in the positive Y-axis direction by the movement mechanism 104, while the laser beam L is irradiated in a pulsed manner. At this time, the laser beam L is fixed without scanning.

[0080] Then, in step St23, the laser beam L is irradiated in a spiral pattern from the radially inside to the radially outside in the first inner circumferential region Z1. This spiral pattern of the laser beam L in the first inner circumferential region Z1 is continuous with the spiral pattern of the laser beam L in the second inner circumferential region Z2 and the spiral pattern of the laser beam L in the outer circumferential region Z0. That is, in the outer circumferential region Z0, the first inner circumferential region Z1, and the second inner circumferential region Z2, the rotation direction of the chuck 100 is the same counterclockwise, and the irradiation direction (movement direction) of the laser beam L is the same from the radially inside to the radially outside, so the spiral pattern of the laser beam L is continuous.

[0081] Furthermore, in step St23, as shown in Figure 19, delamination occurs at the interface between the first wafer W and the laser absorption layer P in the first inner region Z1. This delamination at the interface between the first wafer W and the laser absorption layer P in the first inner region Z1 is continuous with the delamination at the interface between the first wafer W and the laser absorption layer P in the second inner region Z2 and the delamination at the interface in the outer region Z0.

[0082] In step St22, the second inner region Z2, and in step St23, the first inner region Z1, in each irradiation region R, the first wafer W and the laser absorption layer P are separated at the edges Re, or the bonding force is weak, while the first wafer W and the laser absorption layer P remain connected in the center. That is, compared to the outer region Z0, the stress σ accumulated inside the laser absorption layer P is smaller in the second inner region Z2 and the first inner region Z1. To generate such a small stress σ, for example, the frequency of the laser beam L may be reduced (the pitch of the laser beam L may be increased), or the irradiation intensity of the laser beam L may be reduced. If the pitch of the laser beam L is increased, the time required for laser processing can be shortened, and throughput can be improved. Also, if the irradiation intensity of the laser beam L is reduced, laser processing can be performed efficiently.

[0083] Here, in the second inner region Z2 and the first inner region Z1, a large stress σ is generated that causes the interface between the first wafer W and the laser absorption layer P to completely delaminate. If this stress σ accumulates, there is a risk that the first wafer W may crack. Therefore, as described above, in the second inner region Z2 and the first inner region Z1, delamination occurs while at least a portion of the interface between the first wafer W and the laser absorption layer P remains connected, thereby suppressing cracking of the first wafer W.

[0084] Then, as shown in Figure 19, when the delamination E3 at the interface between the first wafer W and the laser absorption layer P in the first inner region Z1 leads to delamination E1 in the outer region Z0, the entire interface between the first wafer W and the laser absorption layer P in both the first inner region Z1 and the second inner region Z2 delaminates. The aforementioned "state of weak bonding force between the first wafer W and the laser absorption layer P at the edge Re" refers to a bonding force such that the edge Re delaminates when the delamination E3 at the interface between the first wafer W and the laser absorption layer P in the first inner region Z1 leads to delamination E1 in the outer region Z0.

[0085] Next, in step St24, the rotation of the chuck 100 is stopped in the central region Z3. Then, laser light L is irradiated in a pulsed manner from the laser irradiation unit 110. The laser light L is also scanned in the central region Z3. At this time, as shown in Figure 20, the scanning irradiation 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 are repeated alternately. Alternatively, the scanning irradiation of the laser light L in the X-axis direction and the negative Y-axis movement of the chuck 100 may be synchronized. In order to improve the throughput of wafer processing, the laser light L may be branched by the optical system 112 described above and the laser light L may be irradiated simultaneously at multiple points on the laser absorption layer P. Furthermore, due to the delamination mechanism between the first wafer W and the laser absorption layer P caused by the irradiation of the laser light L described above, delamination occurs at the interface between the first wafer W and the laser absorption layer P in the central region Z3.

[0086] According to this embodiment, by performing steps St20 to St24, delamination can be caused at the interface between the first wafer W and the laser absorption layer P. As a result, the first wafer W and the laser absorption layer P can be separated, and the device layer Dw of the first wafer W can be transferred to the second wafer S.

[0087] Furthermore, in step St21, the laser beam L is irradiated in the outer peripheral region Z0 by moving it from the radially inner side to the outer side, which can cause delamination at the interface between the first wafer W and the laser absorption layer P. This reduces the bonding strength at the interface between the first wafer W and the laser absorption layer P, and allows the first wafer W and the laser absorption layer P to be separated.

[0088] Furthermore, in the second inner circumferential region Z2 of step St22 and the first inner circumferential region Z1 of step St23, the laser beam L is continuously irradiated from the radially inner side to the outer side, which allows for proper delamination at the interface between the first wafer W and the laser absorption layer P.

[0089] Furthermore, considering the proper transport of the polymerized wafer T after irradiation with laser light L in the laser irradiation device 31, as described above, it is preferable that at least a portion of the interface between the first wafer W and the laser absorption layer P remains connected. Therefore, it is preferable to maintain a connected state of at least a portion of the interface between the first wafer W and the laser absorption layer P in at least one of the first inner region Z1, the second inner region Z2, and the central region Z3.

[0090] Furthermore, in order to enjoy the effects of the above embodiment, that is, to delaminate at the interface between the first wafer W and the laser absorption layer P in at least the outer peripheral region Z0, it is sufficient to irradiate the outer peripheral region Z0 with laser light L from the radially inner side outward. Other processing conditions are not limited to the above embodiment.

[0091] Specifically, the processing conditions for laser treatment can be arbitrarily changed for each region Z0 to Z3. These processing conditions include, for example, the rotation speed of the chuck 100, the frequency of the laser beam L, the rotation direction of the chuck 100, and the processing order of regions Z0 to Z3 (the irradiation order of the laser beam L).

[0092] For example, as shown in Figure 21, the laser beam L may be irradiated onto the second inner region Z2, the first inner region Z1, the outer region Z0, and the central region Z3 in this order.

[0093] In such a case, as shown in Figure 21(a), in the second inner circumference region Z2 and the first inner circumference region Z1, the chuck 100 is rotated counterclockwise by the rotation mechanism 103, similar to steps St22 and St23, and the chuck 100 is moved in the positive Y-axis direction by the movement mechanism 104 while the laser beam L is irradiated in a pulsed manner.

[0094] In the second inner peripheral region Z2 and the first inner peripheral region Z1, in each irradiation region R, the first wafer W and the laser absorption layer P are separated at the edge Re, or the bonding force is weak, while the first wafer W and the laser absorption layer P remain connected in the central part. In other words, the stress σ accumulated inside the laser absorption layer P is reduced in the second inner peripheral region Z2 and the first inner peripheral region Z1. As mentioned above, if a large stress σ is generated and accumulated, there is a risk that the first wafer W will crack. In this respect, by reducing the stress σ as in this embodiment, cracking of the first wafer W can be suppressed. The aforementioned "state where the bonding force between the first wafer W and the laser absorption layer P is weak at the edge Re" refers to a bonding force such that the edge Re is separated when the delamination E3 at the interface between the first wafer W and the laser absorption layer P in the first inner peripheral region Z1 leads to delamination E1 in the outer peripheral region Z0.

[0095] Next, as shown in Figure 21(b), in the outer peripheral region Z0, similar to step St21, the chuck 100 is rotated counterclockwise by the rotation mechanism 103, and the chuck 100 is moved in the positive Y-axis direction by the movement mechanism 104 while the laser beam L is irradiated in a pulsed manner. In the outer peripheral region Z0, a large stress σ is generated in each irradiation region R such that delamination E1 occurs from the center to the edge Re.

[0096] Next, in the central region Z3, the laser beam L is scanned with the rotation of the chuck 100 stopped, similar to step St24. Then, in the central region Z3, delamination occurs at the interface between the first wafer W and the laser absorption layer P.

[0097] In this embodiment as well, the same effects as in the above embodiment can be enjoyed. That is, delamination can be caused at the interface between the first wafer W and the laser absorption layer P.

[0098] Alternatively, as shown in Figure 22, the laser beam L may be irradiated in the first inner circumferential region Z1 and the second inner circumferential region Z2 while moving from the radially outer side to the inner side. In this case, the laser beam L is irradiated to the outer circumferential region Z0, the laser beam L is irradiated to the first inner circumferential region Z1, the laser beam L is irradiated to the second inner circumferential region Z2, and the laser beam L is irradiated to the central region Z3 in this order.

[0099] First, as shown in Figure 22(a), in the outer peripheral region Z0, similar to step St21, the chuck 100 is rotated counterclockwise by the rotation mechanism 103, and the chuck 100 is moved in the positive Y-axis direction by the movement mechanism 104, while the laser beam L is irradiated in a pulsed manner. As a result, in the outer peripheral region Z0, the laser beam L is irradiated in a spiral pattern from the radially inner to the outer side. In the outer peripheral region Z0, a large stress σ is generated in each irradiated region R such that peeling E1 occurs from the center to the end Re.

[0100] Next, as shown in Figure 22(b), in the first inner circumference region Z1, the chuck 100 is rotated clockwise by the rotation mechanism 103, and the chuck 100 is moved in the negative Y-axis direction by the movement mechanism 104, while the laser beam L is irradiated in a pulsed manner. As a result, in the first inner circumference region Z1, the laser beam L is irradiated in a spiral pattern from the radially outer side to the inner side.

[0101] In this case, the rotation direction of the chuck 100 is opposite to that of the adjacent outer peripheral region Z0 and the first inner peripheral region Z1, and the irradiation direction of the laser beam L is also opposite. As a result, the spiral shape of the laser beam L can be made continuous in the outer peripheral region Z0 and the first inner peripheral region Z1. In other words, if the irradiation direction of the laser beam L is different in adjacent regions, the spiral shape of the laser beam L can be made continuous by reversing the rotation direction of the chuck 100 in those adjacent regions.

[0102] Next, in the second inner circumference region Z2, the chuck 100 is rotated clockwise by the rotation mechanism 103, and the chuck 100 is moved in the negative Y-axis direction by the movement mechanism 104, while the laser beam L is irradiated in a pulsed manner. As a result, in the second inner circumference region Z2, the laser beam L is irradiated in a spiral pattern from the radially outer side to the inner side.

[0103] Furthermore, the magnitude of the stress σ accumulated inside the laser absorption layer P in the first inner region Z1 and the second inner region Z2 is not limited. When the first inner region Z1 is irradiated with laser light L, the delamination at the interface between the first wafer W and the laser absorption layer P caused by the laser light L leads to delamination E1 in the outer region Z0. Therefore, in the first inner region Z1, delamination occurs appropriately at the interface between the first wafer W and the laser absorption layer P. This delamination is then transmitted to the second inner region Z2, and in the second inner region Z2, delamination also occurs appropriately at the interface between the first wafer W and the laser absorption layer P.

[0104] Next, in the central region Z3, the laser beam L is scanned with the rotation of the chuck 100 stopped, similar to step St24. Then, in the central region Z3, delamination occurs at the interface between the first wafer W and the laser absorption layer P.

[0105] In this embodiment as well, the same effects as in the above embodiment can be enjoyed. That is, delamination can be caused at the interface between the first wafer W and the laser absorption layer P.

[0106] In the above embodiment, the inner circumference region was set to two parts, a first inner circumference region Z1 and a second inner circumference region Z2, in step St20, but there may be only one inner circumference region. In this inner circumference region, the frequency of the laser beam L may be kept constant, and the rotation speed of the polymerized wafer T may be varied in accordance with the radial movement of the laser beam L, thereby irradiating the wafer with the laser beam L in a pulsed manner. Alternatively, in the inner circumference region, the rotation speed of the polymerized wafer T may be kept constant, and the frequency of the laser beam L may be varied in accordance with the radial movement of the laser beam L, thereby irradiating the wafer with the laser beam L in a pulsed manner. In any case, in the inner circumference region, the processing conditions are controlled so that the irradiation interval of the laser beam L is constant.

[0107] In the above embodiment, the chuck 100 was moved horizontally when performing laser processing, but the lens 113 of the laser irradiation unit 110 may be moved horizontally, or both the chuck 100 and the lens 113 may be moved horizontally. By moving the chuck 100 and the lens 113 relatively horizontally, laser processing with the laser beam L can be performed.

[0108] In the above embodiment, in step St24, the laser beam L was scanned and irradiated onto the central region Z3 with the rotation of the chuck 100 stopped. However, as shown in Figure 23, the laser beam L may be scanned and irradiated from the laser irradiation unit 110 while the chuck 100 is rotating. In this case, the rotation speed of the chuck 100 in the central region Z3 may be lower than that of the outer region Z0, the first inner region Z1, and the second inner region Z2.

[0109] In the embodiments described above, the laser beam L was irradiated in a spiral pattern in the outer peripheral region Z0, the first inner peripheral region Z1, and the second inner peripheral region Z2, but it may also be irradiated in a concentric, annular pattern. Furthermore, in the embodiment shown in Figure 23, the laser beam L was irradiated in a spiral pattern in the central region Z3, but it may also be irradiated in a concentric, annular pattern.

[0110] In the embodiments described above, delamination was caused at the interface between the first wafer W and the laser absorption layer P, as shown in Figures 8 to 11. However, as mentioned above, a delamination-promoting film may be formed on the surface Wa of the first wafer W to appropriately facilitate the delamination of the first wafer W and the laser absorption layer P, and in this case, delamination may be caused at the interface between the delamination-promoting film and the laser absorption layer P.

[0111] Specifically, as shown in Figure 24(a), the surface Wa of the first wafer W may be formed by laminating a delamination-promoting film Pe, a laser absorption layer P, a device layer Dw, and a surface film Fw in that order. The delamination-promoting film Pe is formed to facilitate the delamination of the first wafer W from the second wafer S, and is formed from a material that has lower adhesion to the first wafer W (silicon) than to the laser absorption layer P, and is transparent to laser light L, such as silicon nitride (SiN).

[0112] In separating the first wafer W from the second wafer S, first, the laser absorption layer P is irradiated with laser light L (step St31 in Figure 25). The laser light L passes through the first wafer W and the peel-promoting film Pe and is absorbed by the laser absorption layer P (step St32 in Figure 25).

[0113] The laser light L absorbed by the laser absorption layer P is converted into heat according to its energy distribution (step St33 in Figure 25), causing the temperature of the laser absorption layer P to rise. Most of the heat generated in the laser absorption layer P due to the absorption of the laser light L diffuses to the peel-promoting film Pe on the first wafer W side (step St34 in Figure 25), and this heat diffusion causes the temperature of the interface between the laser absorption layer P and the peel-promoting film Pe to rise.

[0114] When the heat generated in the laser absorption layer P diffuses to the first wafer W, the effect of this heat, i.e., the increase in the interface temperature between the laser absorption layer P and the peel-promoting film Pe, causes the peel-promoting film Pe to expand locally according to its temperature distribution, as shown in Figure 24(b) (step St35 in Figure 25). At this time, the thermal effect at the interface between the laser absorption layer P and the peel-promoting film Pe may also affect the first wafer W, and as shown in Figure 24(b), the first wafer W may also expand locally according to its temperature distribution.

[0115] Subsequently, when the peel-promoting film Pe (and the first wafer W) expands locally, the stress generated by this expansion causes delamination at the interface between the laser absorption layer P and the peel-promoting film Pe, which has low adhesion, as shown in Figure 24(c). As a result, the bonding strength between the laser absorption layer P and the peel-promoting film Pe decreases (step St36 in Figure 25). Then, by connecting the delamination across the entire interface between the peel-promoting film Pe and the laser absorption layer P, the bonding strength is reduced across the entire surface of the peel-promoting film Pe and the laser absorption layer P, thereby allowing the separation device 32 to properly separate the peel-promoting film Pe and the laser absorption layer P (the first wafer W and the second wafer S) (step St37 in Figure 25).

[0116] Thus, by forming a peel-promoting film Pe on the surface Wa of the first wafer W, where the adhesion to the first wafer W (silicon) is lower than the adhesion to the laser absorption layer P, and by expanding the peel-promoting film Pe instead of the first wafer W, or together with the first wafer W, the transfer of the device layer Dw formed on the surface Wa of the first wafer W can be appropriately performed.

[0117] In the example shown in Figure 24, the peel-promoting film Pe was formed at the interface between the first wafer W and the laser absorption layer P. However, for example, the peel-promoting film Pe could be formed at the interface between the laser absorption layer P and the device layer Dw, and peeling could be caused at the interface between the laser absorption layer P and the peel-promoting film Pe, thereby leaving the peel-promoting film Pe on the second wafer S side, which is the transfer destination for the device layer Dw.

[0118] The embodiments disclosed herein should be considered in all respects as illustrative and not restrictive. The embodiments described above may be omitted, replaced, or modified in various ways without departing from the scope and spirit of the appended claims. For example, the constituent elements of the embodiments described above can be combined in any way. Such any combination will naturally yield the functions and effects of each constituent element in the combination, as well as other functions and effects that will be apparent to those skilled in the art from the description herein.

[0119] Furthermore, the effects described herein are merely descriptive or illustrative and not limiting. In other words, the technology relating to this disclosure may produce other effects that will be apparent to those skilled in the art from the description herein, in addition to or instead of the effects described herein. [Explanation of symbols]

[0120] 31 Laser irradiation device 40 Control device 100 Chuck 103 Rotation mechanism 104 Moving mechanism 110 Laser irradiation area L Laser light P laser absorption layer S Second wafer T Polymerized wafer W First wafer

Claims

1. A program that runs on a computer of a control device that controls a substrate processing apparatus, causing the substrate processing apparatus to execute a substrate processing method for processing a polymerized substrate formed by laminating a first substrate, an interface layer including at least a laser absorption layer, and a second substrate, The substrate processing apparatus is A substrate holding portion for holding the polymerized substrate, A laser irradiation unit that irradiates the polymerized substrate held in the substrate holding unit with laser light, A moving mechanism that moves the substrate holding portion and the laser irradiation portion relative to each other in the horizontal direction, A rotating mechanism for rotating the substrate holding portion, The control device comprises a program storage unit for storing the program, The substrate processing method is The polymerized substrate is defined as having an outer peripheral region including the unbonded region between the first substrate and the second substrate, and an inner peripheral region located radially inside the outer peripheral region and positioned in the bonded region between the first substrate and the second substrate, and is held by the substrate holding portion. The polymerized substrate held in the substrate holding section is rotated, and laser light is irradiated onto the polymerized substrate from the laser irradiation section while moving radially, thereby causing delamination at the interface between the first substrate and the laser absorption layer, or at the interface between the interface layer and the laser absorption layer. In the inner circumferential region, the laser light is irradiated, This includes irradiating the outer peripheral region with the laser light while moving it radially from the inside outwards, The program is executed after irradiating the inner region with the laser beam, moving the laser beam radially from the inside to the outside in the outer region.

2. The aforementioned interface layer includes a peel-promoting film, The program according to claim 1, wherein, in the substrate processing method, delamination of the interface between the interface layer and the laser absorption layer is caused at the interface between the delamination promoting film and the laser absorption layer.

3. The substrate processing method is In the aforementioned inner circumference region, a first inner circumference region is defined on the radially outer side, and a second inner circumference region is defined on the radially inner side. In the first inner circumference region, the frequency of the laser beam is kept constant, and the rotational speed of the polymerization substrate is varied in accordance with the movement of the laser beam, thereby irradiating the laser beam in a pulsed manner. The program according to claim 1, further comprising: keeping the rotation speed of the polymerization substrate constant in the second inner circumference region, and varying the frequency of the laser light in accordance with the movement of the laser light to irradiate the laser light in a pulsed manner.

4. The substrate processing method is In the polymerization substrate, a central region is set which is located radially inside the inner circumferential region and in the bonding region between the first substrate and the second substrate. The program according to claim 1, further comprising irradiating the central region with the laser beam while scanning, with the rotation of the polymerization substrate stopped.

5. The program according to claim 1, wherein the pitch of the laser beam in the inner region is made longer than the pitch of the laser beam in the outer region, in the substrate processing method.

6. A substrate processing apparatus for processing a polymerized substrate formed by laminating a first substrate, an interface layer including at least a laser absorption layer, and a second substrate, A substrate holding portion for holding the polymerized substrate, A laser irradiation unit that irradiates the polymerized substrate held in the substrate holding unit with laser light, A moving mechanism that moves the substrate holding portion and the laser irradiation portion relative to each other in the horizontal direction, A rotating mechanism for rotating the substrate holding portion, A program storage unit for storing programs, The control device includes a computer that reads the program from the program storage unit and operates the program, The program is a program that runs on the computer of the control device that controls the substrate processing device to cause the substrate processing device to execute a substrate processing method, The substrate processing method is The polymerized substrate is defined as having an outer peripheral region including the unbonded region between the first substrate and the second substrate, and an inner peripheral region located radially inside the outer peripheral region and positioned in the bonded region between the first substrate and the second substrate, and is held by the substrate holding portion. The polymerized substrate held in the substrate holding section is rotated, and laser light is irradiated onto the polymerized substrate from the laser irradiation section while moving radially, thereby causing delamination at the interface between the first substrate and the laser absorption layer, or at the interface between the interface layer and the laser absorption layer. In the inner circumferential region, the laser light is irradiated, This includes irradiating the outer peripheral region with the laser light while moving it radially from the inside outwards, A substrate processing apparatus in which the laser beam is irradiated in the outer peripheral region while moving it from the radially inner to the outer peripheral region is performed after the laser beam is irradiated in the inner peripheral region.

7. The aforementioned interface layer includes a peel-promoting film, The substrate processing apparatus according to claim 6, wherein the delamination of the interface between the interface layer and the laser absorption layer is caused at the interface between the delamination promoting film and the laser absorption layer.

8. The substrate processing method is In the aforementioned inner circumference region, a first inner circumference region is defined on the radially outer side, and a second inner circumference region is defined on the radially inner side. In the first inner circumference region, the frequency of the laser beam is kept constant, and the rotational speed of the polymerization substrate is varied in accordance with the movement of the laser beam, thereby irradiating the laser beam in a pulsed manner. The substrate processing apparatus according to claim 6, further comprising: keeping the rotation speed of the polymerization substrate constant in the second inner circumferential region, and irradiating the laser beam in a pulsed manner by varying the frequency of the laser beam as the laser beam moves.

9. The substrate processing method is In the polymerization substrate, a central region is set which is located radially inside the inner circumferential region and in the bonding region between the first substrate and the second substrate. The substrate processing apparatus according to claim 6, further comprising irradiating the central region with the laser light while scanning it, with the rotation of the polymerization substrate stopped.

10. The substrate processing apparatus according to claim 6, wherein the pitch of the laser beam in the inner region is made longer than the pitch of the laser beam in the outer region.

Images