PCB processing system, program and storage medium

Abstract

To appropriately transfer a device layer formed on a second substrate to a first substrate in a laminated substrate in which the first substrate and the second substrate are bonded to each other.SOLUTION: A substrate processing system includes: a program storage part that stores a program; and a control device that includes a computer reading the program from the program storage part and operates the program. The program is a program that operates on a computer of the control device that controls the substrate processing system to cause the substrate processing system to execute a substrate processing method. The substrate processing method includes steps of: irradiating a laser absorbing layer with a laser beam in a pulsed manner from a back surface side of a second substrate; and peeling the second substrate from a first substrate at an interface between the laser absorbing layer and the second substrate, and transferring a second device layer and a second surface film to the first substrate.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a substrate processing system, a program, and a storage medium.

Background Art

[0002] Patent Document 1 discloses a method for manufacturing a semiconductor device. Such a method for manufacturing a semiconductor device includes a heating step of locally heating a peeling oxide film by irradiating a CO2 laser from the back surface of a semiconductor substrate, and a transfer step of causing peeling to occur in the peeling oxide film and / or at the interface between the peeling oxide film and the semiconductor substrate, and transferring a semiconductor element to a 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 transfers a device layer formed on a second substrate to a first substrate in a polymerized substrate in which the first substrate and the second substrate are joined.

Means for Solving the Problems

[0005] One aspect of the present disclosure is a substrate processing system for transferring a device layer formed on a second substrate to a first substrate in a polymer substrate in which a first substrate and a second substrate are joined, wherein the first substrate has a first device layer and a first surface film formed on it in that order from the surface side, and the second substrate has a laser absorption layer, a second device layer and a second surface film formed on it in that order from the surface side, and the first substrate and the second substrate are joined by the first surface film and the second surface film, and the system includes a holding part for holding the back surface of the first substrate, a laser irradiation part for irradiating laser light, a transport part for peeling the second substrate from the first substrate, a program storage part for storing a program, and the program storage part for storing the program The system includes a control device having a computer that reads from and operates the program, wherein the program is a program that operates on the computer of the control device which controls the substrate processing system to execute a substrate processing method, and the substrate processing method comprises: with the holding unit holding the first substrate, the laser irradiation unit irradiating the laser absorption layer with the laser light in a pulsed manner from the back side of the second substrate; and the transport unit peeling the second substrate from the first substrate at the interface between the laser absorption layer and the second substrate, thereby transferring the second device layer and the second surface film to the first substrate. [Effects of the Invention]

[0006] According to this disclosure, in a polymerized substrate in which a first substrate and a second substrate are joined, a device layer formed on the second substrate can be appropriately transferred to the first substrate. [Brief explanation of the drawing]

[0007] [Figure 1] This is an explanatory diagram comparing the power of laser light when using pulsed waves and continuous waves. [Figure 2] This is a side view illustrating the schematic configuration of a polymerized wafer processed in a wafer processing system. [Figure 3]This is a schematic plan view illustrating the general configuration of the wafer processing system. [Figure 4] This is a side view showing a schematic configuration of the laser irradiation device according to this embodiment. [Figure 5] This is a plan view showing a schematic configuration of the laser irradiation device according to this embodiment. [Figure 6] This diagram illustrates the process of irradiating the laser absorption layer with laser light in this embodiment. [Figure 7] This diagram illustrates the process of irradiating the laser absorption layer with laser light in this embodiment. [Figure 8] This is an explanatory diagram showing how laser light is irradiated onto the laser absorption layer in a modified example of this embodiment. [Figure 9] This is an explanatory diagram showing the process of peeling the second wafer from the laser absorption layer. [Figure 10] This is a schematic diagram illustrating the configuration of a laser irradiation unit according to another embodiment. [Figure 11] In another embodiment, this is an explanatory diagram showing how the frequency of laser light is changed using an acousto-optic modulator. [Figure 12] In another embodiment, this is an explanatory diagram showing how the frequency of laser light is changed using an acousto-optic modulator. [Figure 13] This is a schematic diagram illustrating the configuration of a laser irradiation unit according to another embodiment. [Figure 14] This is a schematic diagram illustrating the configuration of a laser irradiation unit according to another embodiment. [Figure 15] This is a side view illustrating the schematic configuration of a laser irradiation device according to another embodiment. [Figure 16] This is a plan view showing a schematic configuration of a laser irradiation device according to another embodiment. [Figure 17] This is an explanatory diagram showing how laser light is irradiated onto the laser absorption layer in another embodiment. [Figure 18] This is an explanatory diagram showing how laser light is irradiated onto the laser absorption layer in another embodiment. [Figure 19]It is an explanatory diagram showing a state where a laser absorption layer is irradiated with laser light in another embodiment. [Figure 20] It is a side view showing an outline of the configuration of a laser irradiation device according to another embodiment. [Figure 21] It is a side view showing an outline of the configuration of a guide portion. [Figure 22] It is a side view showing an outline of the configuration of a holding member. [Figure 23] It is a plan view showing an outline of the configuration of a guide portion and a holding member. [Figure 24] It is an explanatory diagram showing a state where a device layer formed on the surface of a second wafer is transferred to a first wafer in another embodiment. [Figure 25] It is an explanatory diagram showing a state where a device layer formed on the surface of a second wafer is transferred to a first wafer in another embodiment. [Figure 26] It is an explanatory diagram showing a state where a device layer formed on the surface of a second wafer is transferred to a first wafer in another embodiment. [Figure 27] It is an explanatory diagram showing a state where a device layer formed on the surface of a second wafer is transferred to a first wafer in another embodiment. [Figure 28] It is an explanatory diagram showing a state where a device layer formed on the surface of a second wafer is transferred to a first wafer in another embodiment. [Figure 29] It is a side view showing an outline of the configuration of a polymerized wafer in another embodiment.

Embodiments for Carrying Out the Invention

[0008] In recent years, in the manufacturing process of LEDs, so-called laser lift-off, in which a GaN (gallium nitride)-based compound crystal layer (material layer) is peeled off from a sapphire substrate using laser light, is being performed. The background for performing such laser lift-off is that since the sapphire substrate has transparency to short-wavelength laser light (for example, UV light), short-wavelength laser light with a high absorption rate for the absorption layer can be used, and the range of selection for the laser light is also wide.

[0009] On the other hand, in the semiconductor device manufacturing process, a device layer formed on the surface of one substrate (such as a silicon substrate) is transferred to another substrate. Silicon substrates are generally transparent to laser light in the NIR (near-infrared) region, but the absorption layer is also transparent to NIR laser light, so there is a risk of damage to the device layer. Therefore, in order to perform laser lift-off in the semiconductor device manufacturing process, laser light in the FIR (far-infrared) region is used.

[0010] Generally, laser light with a wavelength of FIR can be used, for example, by a CO2 laser. In the method described in Patent Document 1 above, delamination is caused at the interface between the delaminated oxide film and the substrate by irradiating the delaminated oxide film with a CO2 laser.

[0011] Upon diligent investigation by the inventors, it was found that simply irradiating with a CO2 laser may not always cause delamination. In other words, they discovered that the cause of delamination is not the energy amount of the CO2 laser, but the peak power (maximum intensity of the laser light). For example, as shown in Figure 1, when a CO2 laser is continuously oscillated (using a continuous wave), it is difficult to increase the peak power, and delamination may not occur. On the other hand, when a CO2 laser is oscillated in a pulsed manner (using a pulsed wave), the peak power can be increased, and delamination can occur. In this disclosure, the laser light produced by oscillating a CO2 laser in a pulsed manner is a so-called pulsed laser, and its power repeatedly fluctuates between 0 (zero) and its maximum value.

[0012] Furthermore, when a CO2 laser is continuously oscillated, the thermal effects are significant, making it difficult to achieve stable laser lift-off, and there is a risk that the device layer may be damaged by heat. Therefore, from this perspective as well, it is better to irradiate with a CO2 laser in a pulsed manner.

[0013] As described above, in order to separate the substrate from the exfoliated oxide film (device layer), it is necessary to irradiate the exfoliated oxide film with a CO2 laser in a pulsed manner. However, the method described in Patent Document 1 does not consider pulsed lasers at all, nor does it suggest their use. Therefore, there is room for improvement in conventional device layer transfer methods.

[0014] The technology described herein involves appropriately transferring a device layer formed on a second substrate to a first substrate in a polymerized substrate in which a first substrate and a second substrate are joined. 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.

[0015] 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 bonding a first wafer W1 as a first substrate and a second wafer W2 as a second substrate, as shown in Figure 2. Hereinafter, on the first wafer W1, the side that is bonded to the second wafer W2 is referred to as the front surface W1a, and the side opposite to the front surface W1a is referred to as the back surface W1b. Similarly, on the second wafer W2, the side that is bonded to the first wafer W1 is referred to as the front surface W2a, and the side opposite to the front surface W2a is referred to as the back surface W2b.

[0016] The first wafer W1 is a semiconductor wafer, such as a silicon substrate. A device layer D1 and a surface film F1 are stacked on the surface W1a of the first wafer W1 in this order from the surface W1a side. The device layer D1 contains multiple devices. Examples of the surface film F1 include an oxide film (SiO2 film, TEOS film), a SiC film, a SiCN film, or an adhesive. Note that the device layer D1 and surface film F1 may not be formed on the surface W1a.

[0017] The second wafer W2 is also a semiconductor wafer, such as a silicon substrate. On the surface W2a of the second wafer W2, a laser absorption layer P, a device layer D2, and a surface film F2 are stacked in this order from the surface W2a side. 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) is used for the laser absorption layer P, but it is not particularly limited as long as it absorbs laser light. The device layer D2 and the surface film F2 are the same as the device layer D1 and surface film F1 of the first wafer W1, respectively. The surface film F1 of the first wafer W1 and the surface film F2 of the second wafer W2 are then joined together. Note that 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 D2 and the surface film F2. Also, the device layer D2 and surface film F2 may not be formed on the surface W2a. In this case, the laser absorption layer P is formed on the first wafer W1 side, and the device layer D1 on the first wafer W1 side is transferred to the second wafer W2 side.

[0018] As shown in Figure 3, 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 of the processing block 30, which will be described later, is located on the negative X-axis side of the transport block 20, and the cleaning device 32, which will be described later, is located on the positive X-axis side of the transport block 20.

[0019] The loading / unloading block 10 loads cassettes Ct, Cw1, and Cw2, each capable of accommodating multiple polymerized wafers T, multiple first wafers W1, and multiple second wafers W2, 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, Cw1, and Cw2, can be freely mounted on the cassette mounting table 11 in a line along the X-axis. The number of cassettes Ct, Cw1, and Cw2 mounted on the cassette mounting table 11 is not limited to this embodiment and can be determined arbitrarily.

[0020] The transport block 20 is provided with a wafer transport device 22 that is configured to move freely on 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 W1, and the second wafer W2. Each transport arm 23 is configured to move freely in the horizontal direction, the vertical direction, 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 W1, and the second wafer W2 to the cassettes Ct, Cw1, Cw2 of the cassette mounting table 11, the laser irradiation device 31 and the cleaning device 32, which will be described later.

[0021] The processing block 30 includes a laser irradiation device 31 and a cleaning device 32. The laser irradiation device 31 irradiates the laser absorption layer P of the second wafer W2 with laser light. The configuration of the laser irradiation device 31 will be described later.

[0022] The cleaning device 32 cleans the surface of the laser absorption layer P formed on the surface W1a of the first wafer W1 separated by the laser irradiation device 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 device 32 may also be configured to clean the back surface W1b of the first wafer W1 in addition to the surface W1a.

[0023] 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 drive systems such as the various processing devices and transport devices described above to realize the wafer processing in the wafer processing system 1 described later. Note that 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.

[0024] Next, the laser irradiation device 31 described above will be explained.

[0025] As shown in Figures 4 and 5, the laser irradiation device 31 has a chuck 100 as a holding part that holds the polymerized wafer T on its upper surface. The chuck 100 adsorbs and holds the entire surface W1b of the back surface W1b of the first wafer W1. The chuck 100 may also adsorb and hold a portion of the back surface W1b. 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 move up and down.

[0026] 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 freely around the θ axis (vertical axis) via the air bearing 101 through the rotating mechanism 103. The slider table 102 is configured to move along a rail 105 that extends in the Y-axis direction and is provided on the base 106, 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.

[0027] 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. The laser head 111 emits laser light in a pulsed manner. The optical system 112 controls the intensity and position of the laser light, or adjusts the output by attenuating the laser light. The lens 113 is a cylindrical member that irradiates the polymerized wafer T held by the chuck 100 with laser light. In this embodiment, the laser light is CO2 laser light, and the laser light emitted from the laser irradiation unit 110 passes through the second wafer W2 and irradiates the laser absorption layer P. The wavelength of the CO2 laser light is, for example, 8.9 μm to 11 μm. The lens 113 is configured to be able to move up and down by a lifting mechanism (not shown).

[0028] Furthermore, a transport pad 120 is provided above the chuck 100 as a transport section. The transport pad 120 is configured to be able to move up and down by a lifting mechanism (not shown). The transport pad 120 also has a suction surface for the second wafer W2. The transport pad 120 then transports the second wafer W2 between the chuck 100 and the transport arm 23. Specifically, after moving the chuck 100 to below the transport pad 120 (the handover position with the transport arm 23), the transport pad 120 suctions and holds the back surface W2b of the second wafer W2 and detaches it from the first wafer W1. Subsequently, the detached second wafer W2 is transferred from the transport pad 120 to the transport arm 23 and discharged from the laser irradiation device 31. The transport pad 120 may also be configured to invert the front and back surfaces of the wafer by an inversion mechanism (not shown).

[0029] In the laser irradiation device 31 shown in Figure 5, the transport arm 23 accesses the transport pad 120 from the positive X-axis direction. However, the laser irradiation device 31 shown in Figure 5 may be rotated 90 degrees counterclockwise, and the transport arm 23 may access the transport pad 120 from the negative Y-axis direction.

[0030] When the polymerized wafer T is loaded into the laser irradiation device 31, the polymerized wafer T is transferred from the transport arm 23 to the lifting pin, and then lowered by the lifting pin to be placed on the chuck 100. When the peeled first wafer W1 is removed from the laser irradiation device 31, the polymerized wafer T placed on the chuck 100 is raised by the lifting pin and then transferred from the lifting pin to the transport arm 23.

[0031] 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 W1 and the second wafer W2 are bonded together in an external bonding device (not shown) to the wafer processing system 1 to form a polymerized wafer T in advance.

[0032] First, a cassette Ct containing multiple polymerized wafers T is placed on the cassette mounting table 11 of the loading / unloading block 10.

[0033] 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 lifting pin and held by the chuck 100. Subsequently, the moving mechanism 104 moves the chuck 100 to the processing position. 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.

[0034] Next, as shown in Figures 6 and 7, 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 second wafer W2. At this time, the laser light L passes through the second wafer W2 from the back surface W2b side and is absorbed by the laser absorption layer P. This laser light L causes delamination at the interface between the laser absorption layer P and the second wafer W2. Almost all of the laser light L is absorbed by the laser absorption layer P and does not reach the device layer D2. Therefore, damage to the device layer D2 can be suppressed.

[0035] When irradiating the laser absorption layer P with laser light L, the rotation mechanism 103 rotates the chuck 100 (polymerized wafer T), and the movement mechanism 104 moves the chuck 100 in the Y-axis direction. As a result, the laser light L is irradiated onto the laser absorption layer P from the radial outside to the inside, resulting in a spiral irradiation from the outside to the inside. The black arrows shown in Figure 7 indicate the rotation direction of the chuck 100.

[0036] The irradiation start position of the laser beam L is preferably between the outer edge Ea of the second wafer W2 and the bonding edge Eb of the first wafer W1 and the second wafer W2 in the polymerized wafer T. In this case, for example, even if the centers of the first wafer W1 and the second wafer W2 are misaligned and eccentric in the polymerized wafer T, the eccentricity can be absorbed and the laser beam L can be appropriately irradiated onto the laser absorption layer P.

[0037] As shown in Figure 8, the laser beam L may be irradiated in a concentric, ring-like pattern in the laser absorption layer P. However, in this case, since the rotation of the chuck 100 and the Y-direction of the chuck 100 alternate, irradiating the laser beam L in a spiral pattern as described above allows for a shorter irradiation time and improved throughput.

[0038] Furthermore, in the laser absorption layer P, the laser beam L may be irradiated from the radially inner side to the radially outer side. However, in this case, since the inner side of the laser absorption layer P delaminates first, the stress associated with delamination is directed radially outward, and areas outside that are not irradiated with the laser beam L may also delaminate. In this regard, as described above, when the laser beam L is irradiated from the radially outer side to the inner side, the stress associated with delamination can be released outward, making it easier to control the delamination. In addition, by appropriately controlling the delamination, it is possible to suppress roughness of the delamination surface.

[0039] Furthermore, in this embodiment, when irradiating the laser absorption layer P with laser light L, the chuck 100 was rotated, but the lens 113 may be moved and rotated relative to the chuck 100. Also, in this embodiment, the chuck 100 was moved in the Y-axis direction, but the lens 113 may be moved in the Y-axis direction.

[0040] In this way, the laser irradiation device 31 irradiates the laser absorption layer P with laser light L. Since the laser light L is irradiated in a pulsed manner, the peak power of the laser light L can be increased. Therefore, as explained using Figure 1 above, delamination can be caused at the interface between the laser absorption layer P and the second wafer W2, and the second wafer W2 can be properly separated from the laser absorption layer P.

[0041] Next, the chuck 100 is moved to the transfer position by the moving mechanism 104. Then, as shown in Figure 9(a), the transport pad 120 holds the back surface W2b of the second wafer W2 by suction. After that, as shown in Figure 9(b), with the transport pad 120 holding the second wafer W2 by suction, the transport pad 120 is raised to detach the second wafer W2 from the laser absorption layer P. At this time, as described above, delamination occurs at the interface between the laser absorption layer P and the second wafer W2 due to irradiation with laser light L, so the second wafer W2 can be detached from the laser absorption layer P without applying a large load.

[0042] The peeled second wafer W2 is transferred from the transport pad 120 to the transport arm 23 of the wafer transport device 22 and then transported to the cassette Cw2 on the cassette mounting table 11. Alternatively, the second wafer W2, after being removed from the laser irradiation device 31, may be transported to the cleaning device 32 before being transported to the cassette Cw2, and its peeled surface W2a may be cleaned. In this case, the transport pad 120 may be used to invert the front and back surfaces of the second wafer W2 before it is transferred to the transport arm 23.

[0043] Meanwhile, the first wafer W1 held in the chuck 100 is lifted from the chuck 100 by a lifting pin, handed over 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 W1b of the first wafer W1 may also be cleaned in the cleaning device 32 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 W1b of the first wafer W1, respectively.

[0044] Subsequently, the first wafer W1, after all processing has been performed, is transported by the wafer transport device 22 to the cassette Cw1 on the cassette tray 11. This completes the series of wafer processing steps in the wafer processing system 1.

[0045] According to the above embodiment, in the laser irradiation device 31, the laser light L is irradiated onto the laser absorption layer P in a pulsed manner, so the peak power of the laser light L can be increased, and as a result, delamination can be caused at the interface between the laser absorption layer P and the second wafer W2. Furthermore, when the laser light L is irradiated in a pulsed manner, the thermal effect is smaller and stable laser lift-off can be performed compared to when a continuous wave is used. Therefore, the second wafer W2 can be properly peeled off from the laser absorption layer P and the device layer D2 can be transferred to the first wafer W1.

[0046] Here, in order to ensure uniform separation of the first wafer W1 and the second wafer W2 across the wafer surface, it is preferable to keep the interval between irradiations of the laser beam L, i.e., the pulse interval, constant. However, when rotating the chuck 100 (polymerized wafer T) to keep the pulse interval constant, the rotation speed of the chuck 100 increases as the laser beam L moves from the radial outside to the inside. In such a case, when the rotation speed of the chuck 100 reaches its upper limit, as the irradiation position of the laser beam L moves radially inward, the interval between the laser beams L decreases, and in the center, the laser beams L may overlap. Therefore, it is necessary to adjust the irradiation interval of the laser beam L, and there are two methods, for example, as described below.

[0047] The first method involves controlling the rotation speed of the chuck 100. Specifically, the rotation speed is slowed down when the laser beam L is irradiated radially outside the laser absorption layer P, and increased when the laser beam L is irradiated inward. The specific adjustment of this rotation speed can be arbitrarily set according to the frequency of the laser beam L. In this case, the rotation speed of the chuck 100 can be kept constant, and the interval between irradiations of the laser beam L can be kept constant.

[0048] The second method involves controlling the frequency of the laser beam L. Specifically, the frequency is increased when the laser beam L is irradiated radially outside the laser absorption layer P, and decreased when the irradiation position is inside the laser beam L. The specific adjustment of this frequency can be arbitrarily set according to the rotation speed of the chuck 100. Even in this case, the rotation speed of the chuck 100 can be kept constant, and the interval between irradiations of the laser beam L can be kept constant.

[0049] Furthermore, in order to shorten the processing time (cycle time) for laser irradiation and improve throughput, it is preferable in the first method to maintain the rotational speed of the chuck 100 using a high-frequency laser beam L.

[0050] Alternatively, the first and second methods described above may be used in combination. In this case, the rotational speed of the chuck 100 is slowed down on the radially outward side while increasing the frequency of the laser beam L. On the other hand, the rotational speed of the chuck 100 is increased on the radially inward side while decreasing the frequency of the laser beam L.

[0051] In the second method, when controlling the frequency of the laser beam L, for example, when controlling the frequency of the laser beam L in the laser oscillator of the laser head 111, it is necessary to adjust the parameters considering the output and pulse waveform of the laser beam L. For example, if the energy of the laser beam L required to peel off the outer and inner sides of the laser absorption layer P is the same, increasing the frequency of the laser beam L on the outer side requires increasing the output, and decreasing the frequency of the laser beam L on the inner side requires decreasing the output. Furthermore, changing the frequency of the laser beam L in the laser oscillator also changes the pulse waveform of the laser beam L. Therefore, complex adjustments considering the output and pulse waveform of the laser beam L are necessary, making process control of the laser processing difficult.

[0052] Therefore, in this embodiment, the frequency of the laser light L is controlled using an acousto-optic modulator as an optical element. As described above, the laser irradiation unit 110 has a laser head 111, an optical system 112, and a lens 113.

[0053] As shown in Figure 10, the laser head 111 has a laser oscillator 130 that emits laser light in a pulsed manner. The frequency of the laser light emitted from the laser oscillator 130 is the highest frequency that can be controlled by the acousto-optic modulator 131, which will be described later. The laser head 111 may also have other components besides the laser oscillator 130, such as an amplifier.

[0054] The optical system 112 includes an acousto-optic modulator (AOM) 131 that redirects the laser light from the laser oscillator 130 in different directions, and an attenuator 132 that attenuates the laser light from the laser oscillator 130 and adjusts the output of the laser light. The acousto-optic modulator 131 and the attenuator 132 are installed in this order from the laser oscillator 130 side.

[0055] The acousto-optic modulator 131 is an optical modulator that electrically controls the intensity and position of laser light at high speed. As shown in Figure 11, when laser light L1 from the laser oscillator 130 is incident on the acousto-optic modulator 131, it applies a voltage to change the refractive index of the laser light L1, thereby deflecting the laser light L1 in different directions. Specifically, the angle of deflection of the laser light L1 can be controlled by adjusting the voltage. In this embodiment, for example, the laser light L1 is deflected in two different directions, with the laser light L2 from one direction irradiating the laser absorption layer P, and the laser light L3 from the other direction not irradiating the laser absorption layer P. By controlling the deflection of these laser lights L2 and L3, the frequency of the laser light L2 irradiating the laser absorption layer P can be adjusted.

[0056] In such cases, the frequency of the laser beam L2 irradiated onto the laser absorption layer P can be adjusted by using the acousto-optic modulator 131 to thin out the pulses of the laser beam L1. For example, if the deflection ratio of laser beams L2 and L3 relative to laser beam L1 is set to 100:0 at a certain timing, the laser beam L1 will remain as laser beam L2 and irradiate the laser absorption layer P. On the other hand, if the deflection ratio of laser beams L2 and L3 relative to laser beam L1 is set to 0:100 at another timing, the laser beam L2 will be 0 (zero), and the laser beam L2 will not irradiate the laser absorption layer P. In such cases, the frequency of the laser beam L2 deflected by the acousto-optic modulator 131 shown in Figure 12(b) can be adjusted with respect to the frequency of the laser beam L1 from the laser oscillator 130 shown in Figure 12(a). Furthermore, as described above, since the frequency of laser beam L1 is the highest frequency that the acousto-optic modulator 131 can control, the frequency of laser beam L2 can be adjusted arbitrarily. In Figure 12, the horizontal axis represents time, and the vertical axis represents the intensity of the laser light L2. In other words, the density in the graph of Figure 12 represents the frequency of the laser light L2.

[0057] Moreover, in this case, since the frequency of the laser light L1 emitted from the laser oscillator 130 is not changed, the pulse waveform of the laser light L1 remains unchanged, and the pulse waveform of the laser light L2 can be made the same as the pulse waveform of the laser light L1. Therefore, the frequency of the laser light L2 can be easily adjusted, eliminating the need for the complex adjustments described above, and simplifying the process control of the laser processing.

[0058] In this embodiment, an acousto-optic modulator 131 was used as the optical element, but the embodiment is not limited to this. For example, an electro-optic modulator (EOM) may be used as the optical element. Alternatively, optical deflectors such as acousto-optic deflectors (AODs) or electro-optic deflectors (EODs) may be used.

[0059] Next, a method for controlling the laser beam L2 when irradiating the laser absorption layer P from the laser irradiation unit 110 will be described. As described above, the frequency is increased when the irradiation position of the laser beam L2 is radially outside the laser absorption layer P, and the frequency is decreased when the irradiation position of the laser beam L2 is inside.

[0060] The following explanation uses a specific example. Note that the numerical values ​​in this example are just examples, and this disclosure is not limited to these values. For example, let's assume that the energy required for delamination is 400 μJ on both the radially outer and inner sides of the laser absorption layer P. Let's assume that the required frequency of the laser beam L2 on the radially outer side of the laser absorption layer P is 100 kHz, and the required frequency of the laser beam on the inner side is 50 kHz. Let's assume that the frequency of the laser beam L1 from the laser oscillator 130 is 100 kHz and the output is 40 W.

[0061] In this case, the acousto-optic modulator 131 does not thin out the pulses of laser light L1 from the laser oscillator 130 with respect to the radially outer side of the laser absorption layer P. This allows the frequency of the laser light L2 irradiated onto the laser absorption layer P to be the same as the frequency of laser light L1, which is 100 kHz. Furthermore, the output power of laser light L2 becomes the same as the output power of laser light L1, which is 40 W. The energy of laser light L2 becomes 400 μJ (= 40 W / 100 kHz), enabling proper delamination.

[0062] On the other hand, for the radially inner side of the laser absorption layer P, the acousto-optic modulator 131 reduces the pulses of laser light L1 from the laser oscillator 130 by half. As a result, the frequency of the laser light L2 irradiated onto the laser absorption layer P can be reduced to 50 kHz, which is half the frequency of laser light L1. Furthermore, this reduction in laser light L1 also reduces the output of laser light L2 to 20 W, which is half the output of laser light L1. The energy of laser light L2 becomes 400 μJ (= 20 W / 50 kHz), allowing for proper delamination.

[0063] In this way, the rotation speed of the chuck 100 is controlled so that the pulse interval remains constant according to the frequency and irradiation position of the laser beam L2. Then, at the center of the laser absorption layer P, the maximum rotation speed of the chuck 100 is maintained, and the acousto-optic modulator 131 adjusts the frequency of the laser beam L2 in accordance with this maximum rotation speed. As a result, laser processing can be performed while maintaining the high rotation speed of the chuck 100 and the high frequency of the laser beam L2 to the maximum extent, thereby achieving high-throughput laser processing.

[0064] Furthermore, in this case, since the frequency of the laser light L1 from the laser oscillator 130 is not changed, the pulse waveform of the laser light L1 remains unchanged, and the pulse waveform of the laser light L2 can be made the same as the pulse waveform of the laser light L1. Therefore, the frequency of the laser light L2 can be easily adjusted, enabling continuous and seamless processing. As a result, process control of the laser processing becomes easier, and a stable process can be achieved.

[0065] In this embodiment, since the output of the laser beam L1 from the laser oscillator 130 was 40W, no adjustment of the output was necessary to obtain the 400μJ energy required for peeling. However, if the output of the laser beam L1 were, for example, 50W, the output could be adjusted by attenuating the laser beam L1 output by 20% in the attenuator 132.

[0066] In the laser irradiation unit 110 of the above embodiment, the acousto-optic modulator 131 was provided inside the optical system 112 upstream of the attenuator 132, but its installation location is not limited to this. For example, as shown in Figure 13, the acousto-optic modulator 131 may be provided inside the optical system 112 downstream of the attenuator 132. Alternatively, as shown in Figure 14, the acousto-optic modulator 131 may be provided inside the laser head 111 downstream of the laser oscillator 130. Furthermore, the acousto-optic modulator 131 may be provided in two or more locations at the above installation positions.

[0067] In the laser irradiation unit 110, the frequency and output of the laser beam L2 can be adjusted with the acousto-optic modulator 131, and then the output can be finely adjusted with the attenuator 132. Here, the output of the laser beam L1 emitted from the laser oscillator 130 may vary due to individual differences in the laser oscillator 130. The attenuator 132 can adjust for such output variations. Also, when monitoring the output of the laser beam L1 from the laser oscillator 130 over time, the output can be adjusted by feedback control of the attenuator 132. From the viewpoint of finely adjusting the output of the laser beam L2 with the attenuator 132 in this way, it is preferable that the acousto-optic modulator 131 be provided upstream of the attenuator 132, as shown in Figure 10.

[0068] In the laser irradiation unit 110 of the above embodiment, the attenuator 132 may be omitted. For example, the output of the laser beam L2 can be adjusted by the acousto-optic modulator 131 instead of the attenuator 132. For example, if the output of the laser beam L1 is 50W and the output of the laser beam L2 required for peeling is 40W, the output of the laser beam L2 can be set to 40W by setting the deflection ratio of the laser beams L2 and L3 relative to the laser beam L1 in the acousto-optic modulator 131 to 80:20.

[0069] In the above embodiments, the laser beam L was irradiated onto the laser absorption layer P in a spiral or concentric pattern, but the irradiation pattern of the laser beam L is not limited to these. Furthermore, the configuration of the apparatus that can accommodate such various irradiation patterns is not limited to the laser irradiation apparatus 31 of the above embodiments. In the above laser irradiation apparatus 31, the chuck 100 was rotatable around the θ axis and movable in the direction of one axis (Y axis), but it may be moved in two axes (X axis and Y axis).

[0070] The laser irradiation device 200 shown in Figures 15 and 16 is a device that moves the chuck 100 along two axes (X axis and Y axis). The laser irradiation device 200 has a chuck 210 as a holding part that holds the polymerized wafer T on its upper surface. The chuck 210 holds the back surface W1b of the first wafer W1 by suction. The chuck 210 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 210 and is configured to be able to move up and down.

[0071] The chuck 210 is supported by the slider table 212 via an air bearing 211. A rotating mechanism 213 is provided on the underside of the slider table 212. The rotating mechanism 213 incorporates, for example, a motor as its drive source. The chuck 210 is configured to rotate freely around the θ axis (vertical axis) via the air bearing 211 through the rotating mechanism 213. The slider table 212 is configured to move along a rail 215 that extends in the Y axis direction and is provided on the moving stage 216, via a moving mechanism 214 provided on its underside. The drive source for the moving mechanism 214 is not particularly limited, but for example, a linear motor can be used.

[0072] The moving stage 216 is configured to move along a rail 217 that extends in the X-axis and is provided on the base 218, by a moving mechanism (not shown) provided on its underside. The drive source for the moving mechanism is not particularly limited, but a linear motor can be used, for example. With this configuration, the chuck 210 is rotatable about the θ-axis and movable in the X-axis and Y-axis.

[0073] A laser irradiation unit 220 is provided above the chuck 210. The laser irradiation unit 220 includes a laser head 221, an optical system 222, and a lens 223. The laser head 221 emits laser light L in a pulsed manner. The optical system 222 controls the intensity and position of the laser light L, or adjusts the output by attenuating the laser light L. The lens 223 is a cylindrical member that irradiates the polymerized wafer T held by the chuck 210 with laser light L, for example, CO2 laser light. The lens 223 is configured to be able to move up and down by a lifting mechanism (not shown).

[0074] A galvanometer, for example, is used for the laser head 221. Multiple galvanometer mirrors (not shown) are arranged inside the laser head 221. An f-θ lens is used for the lens 223. With this configuration, the laser light L input to the laser head 221 is reflected by the galvanometer mirrors, propagated to the lens 223 via the optical system 222, and passed through the second wafer W2 to irradiate the laser absorption layer P. By adjusting the angle of the galvanometer mirrors, the laser light L can be scanned with respect to the laser absorption layer P.

[0075] Furthermore, a transport pad 230 is provided above the chuck 210 as a transport section. The transport pad 230 is configured to be able to move up and down by a lifting mechanism (not shown). The configuration of the transport pad 230 is the same as that of the transport pad 120 in the above embodiment.

[0076] In the laser irradiation apparatus 200, the polymerized wafer T is transferred from the transport arm 23 to the lifting pin and held by the chuck 210. Subsequently, the chuck 210 is moved to a processing position by the moving mechanism 214 and the moving stage 216. This processing position is a position where laser light L can be irradiated onto the polymerized wafer T (laser absorption layer P) from the laser irradiation unit 220.

[0077] Next, as shown in Figure 17, laser light L is pulsed onto the laser absorption layer P from the laser irradiation unit 220. At this time, the laser light L passes through the second wafer W2 from the back surface W2b side of the second wafer W2 and is absorbed by the laser absorption layer P.

[0078] When irradiating the laser absorption layer P with laser light L, the laser light L is scanned within a predetermined scan range A (the rectangular area in Figure 17). Next, with the irradiation of laser light L stopped, the chuck 210 is moved in the X-axis direction. This process of irradiating and scanning with laser light L and moving the chuck 210 is repeated to irradiate the laser light L in a straight line in the X-axis direction. Next, the chuck 210 is moved to shift in the Y-axis direction, and the process of irradiating and scanning with laser light L and moving the chuck 210 is repeated as described above to irradiate the laser light L in a straight line in the X-axis direction. As a result, the laser light L is irradiated onto the laser absorption layer P.

[0079] In this embodiment, when irradiating the laser absorption layer P with laser light L, the chuck 210 was moved in the X-axis and Y-axis directions. However, the lens 223 may also be moved to move the lens 223 relative to the chuck 210.

[0080] Next, the chuck 210 is moved to the transfer position by the moving mechanism 214 and the moving stage 216. Then, the transport pad 230 adsorbs and holds the back surface W2b of the second wafer W2, and the transport pad 230 is raised to peel the second wafer W2 from the laser absorption layer P.

[0081] In this embodiment, the same effects as in the above embodiment can be enjoyed. That is, since the laser light L is irradiated onto the laser absorption layer P in a pulsed manner, the peak power of the laser light L can be increased, and as a result, delamination can be appropriately caused at the interface between the laser absorption layer P and the second wafer W2. Moreover, since the laser light L can be irradiated at the same density in the scan range A, the laser light L can be uniformly irradiated onto the laser absorption layer P.

[0082] In this embodiment, there may be multiple laser irradiation units 220. In this case, multiple laser beams L can be irradiated onto the laser absorption layer P, thereby shortening the processing time and further improving throughput.

[0083] In the above embodiment, the irradiation and scanning of the laser beam L and the movement of the chuck 210 were repeated. However, as shown in Figure 18, the irradiation and scanning of the laser beam L may be performed while moving the chuck 210 in a single line along the X-axis. After irradiating the laser beam L in a single line along the X-axis, the chuck 210 is moved to shift in the Y-axis direction, and the laser beam L is irradiated onto the laser absorption layer P.

[0084] In this embodiment, the same effects as in the above embodiment can be enjoyed. That is, since the laser light L is irradiated onto the laser absorption layer P in a pulsed manner, appropriate delamination can be caused at the interface between the laser absorption layer P and the second wafer W2. Moreover, since the irradiation and scanning of the laser light L are not stopped in a line along the X-axis, the processing time for laser irradiation can be shortened, and throughput can be further improved.

[0085] The above embodiments may be combined with the irradiation of a spiral (or concentric) laser beam L and the irradiation and scanning of the laser beam L.

[0086] As described above, when rotating the chuck 210 (polymerized wafer T), in order to keep the pulse interval constant, the rotation speed of the chuck 210 increases as the laser beam L moves from the radial outside to the inside. Therefore, in the above embodiment, the irradiation interval of the laser beam L was adjusted by controlling at least the rotation speed or frequency of the chuck 210.

[0087] In contrast, as shown in Figure 19, the chuck 210 is rotated and moved radially from the outside to the inside of the laser absorption layer P, irradiating it with laser light L in a spiral pattern. When the rotation speed of the chuck 210 reaches its upper limit, the rotation of the chuck 210 is stopped in the center of the laser absorption layer P, and scanning is performed while irradiating the scan range A with laser light L. Although the scan range A is shown as a rectangle, the shape of the scan range A is not limited to this. For example, the scan range A may be circular.

[0088] By changing the irradiation pattern of the laser beam L in the outer periphery and the center of the laser absorption layer P in this way, the laser beams L can be prevented from overlapping, and the interval between irradiations of the laser beam L, i.e., the pulse interval, can be kept constant. As a result, the separation of the first wafer W1 and the second wafer W2 can be performed uniformly across the wafer surface.

[0089] Furthermore, if the irradiation range of the laser beam L of the laser irradiation unit 220 is wide, for example, if the irradiation range is greater than or equal to the diameter of the laser absorption layer P, the laser beam L may be irradiated onto the entire surface of the laser absorption layer P at once.

[0090] In the laser irradiation device 31 of the above embodiment, a guide portion 240 and a holding member 250 may be provided on the upper surface of the chuck 100, as shown in Figure 20.

[0091] As shown in Figure 21, the guide portion 240 guides the polymerized wafer T to the chuck 100. The guide portion 240 has a vertical portion 241 that extends vertically upward from the chuck 100, and an inclined portion 242 that widens in diameter upward from the vertical portion 241. The inner diameter of the vertical portion 241 is slightly larger than the diameter of the polymerized wafer T. The polymerized wafer T, positioned above the chuck 100, is centered by the inclined portion 242, and then guided by the vertical portion 241 to be held in the chuck 100.

[0092] As shown in Figures 22 and 23, the holding members 250 extend vertically upward from the top surface of the chuck 100 and hold the side surface of the second wafer W2. Multiple holding members 250 are arranged on the concentric circles of the chuck 100, for example, at three locations. The holding members 250 are configured to move back and forth so as to contact or separate from the second wafer W2 by a moving mechanism 251. The holding members 250 are also configured to rotate integrally with the chuck 100. By holding the second wafer W2 with the holding members 250, displacement or slippage of the second wafer W2 can be prevented. Notches 233 are formed at the corresponding positions of the holding members 250 in the guide section 240, and the holding members 250 move through the notches 233 so as not to interfere with the guide section 240.

[0093] In this embodiment, both the guide portion 240 and the holding member 250 are provided, but either only the guide portion 240 or only the holding member 250 may be provided. If only the guide portion 240 is provided, the vertical portion 241 can suppress misalignment and sliding of the second wafer W2. In particular, the guide portion 240 is useful when the gap between the vertical portion 241 and the second wafer W2 is within the allowable range for misalignment. However, providing both the guide portion 240 and the holding member 250 enhances the effect of centering the polymerized wafer T and preventing misalignment and sliding of the second wafer W2.

[0094] In this case, at the transfer position, when the polymerized wafer T is held in the chuck 100, the three holding members 250 are retracted to a position where they do not come into contact with the second wafer W2. After that, the chuck 100 holding the polymerized wafer T is moved to the processing position, and then the three holding members 250 are moved to a position where they come into contact with the side surface of the second wafer W2, and the second wafer W2 is held by these holding members 250.

[0095] In this case, if there is no guide portion 240 or holding member 250, when the laser beam L is irradiated spirally from the radial outside to the inside of the laser absorption layer P, as peeling progresses, the chuck 100 rotates, causing centrifugal force to act on the second wafer W2, which can cause the second wafer W2 to shift away from the laser absorption layer P, and potentially resulting in the laser beam L being irradiated to a location other than the processing target during laser processing. There is also a possibility that the peeled second wafer W2 may slide off. In this embodiment, however, the holding member 250 holds the second wafer W2, so such shifting or sliding of the second wafer W2 can be prevented.

[0096] Next, after irradiating with laser light L, the holding member 250 holds the second wafer W2 when moving the chuck 100 to the transfer position. However, during the movement of the chuck 100, an inertial force acts on the second wafer W2, and there is a risk that the second wafer W2 may shift away from the laser absorption layer P. In such a case, when the transport pad 120 subsequently holds the back surface W2b of the second wafer W2 by suction, it will not be possible to hold it in the appropriate position. Therefore, in this embodiment, the holding member 250 holds the second wafer W2 even during the movement of the chuck 100 to prevent the second wafer W2 from shifting.

[0097] The configuration of the holding member for holding the second wafer W2 is not limited to the configuration of the holding member 250 described above. For example, the holding member may hold the second wafer W2 from the side, sandwiching the top and side surfaces of the second wafer W2. Alternatively, the holding member may start holding the second wafer W2 during the laser processing. Furthermore, if the holding member is made of a material that transmits laser light L, such as silicon, it may hold the top surface of the second wafer W2.

[0098] Although the wafer processing system 1 in the above embodiment had a cleaning device 32, the wafer processing system 1 may also have an etching device (not shown). The etching device etches the surface W1a of the first wafer W1 after delamination, specifically the surface of the laser absorption layer P. For example, after scrubbing the surface of the laser absorption layer P with the cleaning device 32, a chemical solution (etching solution) is supplied to the surface of the laser absorption layer P to wet etch the surface. Alternatively, the wafer processing system 1 may have either the cleaning device 32 or the etching device.

[0099] Furthermore, the wafer processing system 1 of the above embodiments may include a CMP apparatus (not shown). In the CMP apparatus, the surface W1a of the first wafer W1 after delamination, specifically the surface of the laser absorption layer P, is subjected to CMP (Chemical Mechanical Polishing). For example, after scrubbing the surface of the laser absorption layer P with the cleaning apparatus 32, the surface of the laser absorption layer P is subjected to CMP treatment to flatten the surface of the laser absorption layer P. The CMP apparatus may be provided outside the wafer processing system 1.

[0100] In the embodiments described above, laser light L was irradiated onto the interface between the laser absorption layer P and the second wafer W2 to peel off the second wafer W2 from the laser absorption layer P. However, as shown in Figure 24, for example, the peeling may be performed in such a way that the laser absorption layer P remains on the second wafer W2.

[0101] In such cases, the laser irradiation device 31 irradiates the interface between the laser absorption layer P and the device layer D2 with pulsed laser light L from the laser irradiation unit 110, as shown in Figure 24(a). This causes delamination at the interface between the laser absorption layer P and the device layer D2.

[0102] The absorption position of the laser beam L, that is, the peeling position of the laser absorption layer P, is adjusted by controlling the energy density of the laser beam L required to peel off the laser absorption layer P, depending on the type of film of the laser absorption layer P. For example, the energy density of the laser beam L can be adjusted by adjusting the numerical aperture (NA) of the laser irradiation unit 110, changing the focus position of the laser beam L, or changing the original output power of the laser beam L.

[0103] Next, with the transport pad 120 adsorbing and holding the back surface W2b of the second wafer W2, the transport pad 120 is raised as shown in Figure 24(b) to peel the laser absorption layer P from the device layer D2.

[0104] In this embodiment as well, the same effects as in the above embodiment can be enjoyed. That is, since the laser light L is irradiated onto the laser absorption layer P in a pulsed manner, the peak power of the laser light L can be increased, and as a result, delamination can be appropriately caused at the interface between the laser absorption layer P and the device layer D2. Moreover, the laser absorption layer P remaining on the second wafer W2 is an oxide film (SiO2 film), and this laser absorption layer P can be used, for example, as an oxide film (insulating film) when fabricating TSV (Through-Silicon Via) on the second wafer W2 in a subsequent semiconductor manufacturing process.

[0105] Furthermore, in this embodiment, the surface of the laser absorption layer P on the second wafer W2 after peeling may be scrubbed clean, and then subjected to CMP treatment using the CMP apparatus described above. In this case, the surface of the laser absorption layer P can be planarized. Then, as described above, it can be appropriately used as an oxide film (insulating film) when manufacturing TSV.

[0106] In the embodiments described above, the case of processing the polymerized wafer T shown in Figure 2 was explained, but the objects to be processed are not limited to this. Below, Figures 25 to 28 will be used to explain the cases of processing different types of polymerized wafers T.

[0107] The processing of the polymerized wafer T shown in Figure 25 will be described. As shown in Figure 25(a), the laser absorption layer P1 formed between the second wafer W2 and the device layer D2 is formed inside the second wafer W2. The second wafer W2 is, for example, an SOI substrate, and the laser absorption layer P1 is, for example, an oxide film (SiO2 film). That is, the Si of the second wafer W2, the SiO2 film of the laser absorption layer P1, and the Si of the Si film S are stacked in order. Note that for the laser absorption layer P1, a film other than the oxide film (SiO2 film), such as silicon germanium (SiGe) or germanium (Ge), may be used, as long as it peels off at the interface with the Si film S.

[0108] Next, as shown in Figure 25(b), a device layer D2 and a surface film F2 are formed on the surface of the laser absorption layer P1. The device layer D2 and the surface film F2 are formed using normal substrate processes (FEOL) and wiring processes (BEOL).

[0109] Next, as shown in Figure 25(c), the first wafer W1 and the second wafer W2 are joined together. A surface film F1 is formed on the surface W1a of the first wafer W1, and this surface film F1 and surface film F2 are joined together.

[0110] Next, in the laser irradiation device 31 of the wafer processing system 1, as shown in Figure 25(d), laser light L is pulsed and irradiated from the laser irradiation unit 110 onto the interface between the laser absorption layer P1 and the Si film S. As a result, delamination occurs at the interface between the laser absorption layer P1 and the Si film S due to this laser light L.

[0111] Next, with the transport pad 120 adsorbing and holding the back surface W2b of the second wafer W2, the transport pad 120 is raised as shown in Figure 25(e) to peel off the laser absorption layer P1 from the Si film S.

[0112] In this embodiment as well, the peeling position of the laser absorption layer P1 may be adjusted, similar to the case shown in Figure 24, to cause peeling at the interface between the second wafer W2 and the laser absorption layer P1.

[0113] The process for processing the polymerized wafer T shown in Figure 26 will now be explained. As shown in Figures 26(a) and (b), a laser absorption layer P2 made of silicon germanium (SiGe) and a Si film S made of Si are stacked in order from the second wafer W2 side between the second wafer W2 and the device layer D2.

[0114] Next, as shown in Figure 26(b), a device layer D2 and a surface film F2 are formed on the surface of the Si film S.

[0115] Next, as shown in Figure 26(c), the first wafer W1 and the second wafer W2 are joined together. A device layer D1 and a surface film F1 are formed on the surface W1a of the first wafer W1, and this surface film F1 and surface film F2 are joined together.

[0116] Next, in the laser irradiation device 31 of the wafer processing system 1, as shown in Figure 26(d), laser light L is pulsed and irradiated from the laser irradiation unit 110 onto the interface between the laser absorption layer P2 and the Si film S. As a result, delamination occurs at the interface between the laser absorption layer P2 and the Si film S due to this laser light L.

[0117] Next, with the transport pad 120 adsorbing and holding the back surface W2b of the second wafer W2, the transport pad 120 is raised as shown in Figure 26(e) to peel off the laser absorption layer P2 from the Si film S. In this embodiment as well, the peeling position of the laser absorption layer P1 may be adjusted to cause peeling at the interface between the second wafer W2 and the laser absorption layer P1, similar to the case shown in Figure 24, by adjusting the absorption position of the laser light L, i.e., the peeling position of the laser absorption layer P1.

[0118] The process for processing the polymerized wafer T shown in Figure 27 will now be explained. As shown in Figures 27(a) and (b), a laser absorption layer P3 made of an oxide film (SiO2 film), a SiGe film S1 made of SiGe, and a Si film S2 made of Si are stacked in order from the second wafer W2 side between the second wafer W2 and the device layer D2.

[0119] Next, as shown in Figure 27(b), a device layer D2 and a surface film F2 are formed on the surface of the Si film S2, which is made of Si.

[0120] Next, as shown in Figure 27(e), the first wafer W1 and the second wafer W2 are joined together. A device layer D1 and a surface film F1 are formed on the surface W1a of the first wafer W1, and this surface film F1 and surface film F2 are joined together.

[0121] Next, in the laser irradiation device 31 of the wafer processing system 1, as shown in Figure 27(d), laser light L is pulsed and irradiated from the laser irradiation unit 110 to the interface between the laser absorption layer P3 and the second wafer W2. As a result, delamination occurs at the interface between the laser absorption layer P3 and the second wafer W2 due to this laser light L.

[0122] Next, with the transport pad 120 adsorbing and holding the back surface W2b of the second wafer W2, the transport pad 120 is raised as shown in Figure 27(e) to peel the second wafer W2 from the laser absorption layer P3.

[0123] The process for processing the polymerized wafer T shown in Figure 28 will be described. The polymerized wafer T has a structure in which Ge-pMOS is stacked on top of Si-nMOS. As shown in Figure 28(a), a device layer D1 and a surface film F1 are formed on the surface W1a of the first wafer W1. That is, the first wafer W1 is Si-nMOS.

[0124] Next, as shown in Figure 28(b), the first wafer W1 and the second wafer W2, which is a Ge-pMOS, are joined together. On the surface W2a of the second wafer W2, a laser absorption layer P4 made of an oxide film (SiO2 film), a device layer D2 made of Ge, and a surface film F2 are formed by stacking them in order from the second wafer W2 side.

[0125] Next, as shown in Figure 28(c), the first wafer W1 and the second wafer W2 are joined together. Specifically, the surface films F1 and F2 are joined together.

[0126] Next, in the laser irradiation device 31 of the wafer processing system 1, as shown in Figure 28(d), laser light L is pulsed and irradiated from the laser irradiation unit 110 onto the interface between the laser absorption layer P4 and the device layer D2. As a result, delamination occurs at the interface between the laser absorption layer P4 and the device layer D2 due to this laser light L.

[0127] Next, with the transport pad 120 adsorbing and holding the back surface W2b of the second wafer W2, the transport pad 120 is raised as shown in Figure 28(e) to peel the laser absorption layer P4 from the device layer D2. In this embodiment as well, the peeling position of the laser absorption layer P1 may be adjusted, similar to the case shown in Figure 24, to cause peeling at the interface between the second wafer W2 and the laser absorption layer P4.

[0128] Regardless of which processing target is shown in Figures 25 to 28 above, the same effects as those of the above embodiments can be enjoyed.

[0129] In the polymerized wafer T processed according to the above embodiments, a reflective film R may be provided between the laser absorption layer P and the device layer D2, as shown in Figure 29. That is, the reflective film R is formed on the side of the laser absorption layer P opposite to the incident surface of the laser light L. A material with high reflectivity to the laser light L and a high melting point, such as a metal film, is used for the reflective film R. Note that the device layer D2 is a functional layer and is different from the reflective film R.

[0130] In this case, the laser light L emitted from the laser irradiation unit 110 passes through the second wafer W2 and is almost entirely absorbed by the laser absorption layer P. However, any remaining laser light L that is not absorbed is reflected by the reflective film R. As a result, the laser light L does not reach the device layer D2, and damage to the device layer D2 can be reliably suppressed.

[0131] Furthermore, the laser light L reflected by the reflective film R is absorbed by the laser absorption layer P. Therefore, the peeling efficiency of the second wafer W2 can be improved.

[0132] 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]

[0133] 31 Laser irradiation device 100 Chuck 110 Laser irradiation area D1, D2 device layer P laser absorption layer T Polymerized wafer W1 First wafer W2, second wafer

Claims

1. A substrate processing system for transferring a device layer formed on the second substrate to the first substrate in a polymerized substrate in which a first substrate and a second substrate are joined, On the first substrate, a first device layer and a first surface film are formed in this order from the surface side. On the second substrate, a laser absorption layer, a second device layer, and a second surface film are formed in this order from the surface side. The first substrate and the second substrate are bonded together by the first surface film and the second surface film. A holding portion for holding the back surface of the first substrate, A laser irradiation unit that emits laser light, A transport unit for separating the second substrate from the first substrate, 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 aforementioned program, A program that runs on the computer of the control device that controls the substrate processing system to cause the substrate processing system to execute a substrate processing method, The substrate processing method is With the holding portion holding the first substrate, the laser irradiation portion irradiates the laser absorption layer with the laser light in a pulsed manner from the back side of the second substrate. A substrate processing system comprising: using the transport unit to peel the second substrate from the first substrate at the interface between the laser absorption layer and the second substrate, thereby transferring the second device layer and the second surface film to the first substrate.

2. In the substrate processing method described above, the laser light is irradiated onto the laser absorption layer from the radially outer side toward the inner side, The substrate processing system according to claim 1, wherein irradiation of the laser light is started from between the outer peripheral edge of the second substrate and the outer peripheral edge of the laser absorption layer which is the bonding end between the first substrate and the second substrate in the polymerized substrate.

3. A rotating mechanism for rotating the holding part, It has a moving mechanism for moving the holding portion in the radial direction, The substrate processing method is The substrate processing system according to claim 1 or 2, comprising alternately rotating the polymerized substrate and moving the polymerized substrate radially, thereby irradiating the laser absorption layer with the laser light in an annular manner.

4. A substrate processing system according to any one of claims 1 to 3, comprising a cleaning device for cleaning the first substrate from which the second substrate has been peeled off.

5. A substrate processing system according to any one of claims 1 to 4, comprising an etching apparatus for etching the first substrate from which the second substrate has been peeled off.

6. A substrate processing system according to any one of claims 1 to 5, comprising a CMP apparatus for CMP processing the first substrate from which the second substrate has been peeled off.

7. It has a rotation mechanism for rotating the holding part, In the substrate processing method described above, the polymerized substrate is rotated while the laser light is irradiated, The substrate processing system according to any one of claims 1 to 6, wherein the rotation speed of the polymerization substrate is faster when the laser light is irradiated inward compared to when it is irradiated radially outward of the laser absorption layer, and the frequency of the laser light irradiated radially outward of the laser absorption layer is greater than the frequency of the laser light irradiated inward.

8. The first surface film is an oxide film, The substrate processing system according to any one of claims 1 to 7, wherein the second surface film is an oxide film.

9. A program that operates on a computer of a control device that controls a substrate processing system, causing the substrate processing system to execute a substrate processing method in which a device layer formed on the second substrate is transferred to the first substrate in a polymerized substrate in which a first substrate and a second substrate are joined together, On the first substrate, a first device layer and a first surface film are formed in this order from the surface side. On the second substrate, a laser absorption layer, a second device layer, and a second surface film are formed in this order from the surface side. The first substrate and the second substrate are bonded together by the first surface film and the second surface film. The substrate processing system is A holding portion for holding the back surface of the first substrate, A laser irradiation unit that emits laser light, A transport unit for separating the second substrate from the first substrate, The control device has a program storage unit for storing the program, The substrate processing method is With the holding portion holding the first substrate, the laser irradiation portion irradiates the laser absorption layer with the laser light in a pulsed manner from the back side of the second substrate. A program comprising: using the transport unit to peel the second substrate from the first substrate at the interface between the laser absorption layer and the second substrate, thereby transferring the second device layer and the second surface film to the first substrate.

10. In the substrate processing method described above, the laser light is irradiated onto the laser absorption layer from the radially outer side toward the inner side, The program according to claim 9, wherein irradiation of the laser light is started from between the outer peripheral edge of the second substrate and the outer peripheral edge of the laser absorption layer which is the bonding end between the first substrate and the second substrate in the polymerized substrate.

11. The substrate processing system is A rotating mechanism for rotating the holding part, It has a moving mechanism for moving the holding portion in the radial direction, The substrate processing method is The program according to claim 9 or 10, comprising alternately rotating the polymerization substrate and moving the polymerization substrate radially, thereby irradiating the laser absorption layer with the laser light in an annular manner.

12. The substrate processing system has a rotating mechanism for rotating the holding portion, In the substrate processing method described above, the polymerized substrate is rotated while the laser light is irradiated, The program according to any one of claims 9 to 11, wherein the rotation speed of the polymerization substrate is faster when the laser light is irradiated inward compared to when it is irradiated radially outward of the laser absorption layer, and the frequency of the laser light irradiated radially outward of the laser absorption layer is greater than the frequency of the laser light irradiated inward.

13. A storage medium readable by a computer, which stores a program that operates on the computer of a control device that controls the substrate processing system, to cause the substrate processing system to execute a substrate processing method for transferring a device layer formed on the second substrate to the first substrate in a polymerized substrate in which a first substrate is joined together, On the first substrate, a first device layer and a first surface film are formed in this order from the surface side. On the second substrate, a laser absorption layer, a second device layer, and a second surface film are formed in this order from the surface side. The first substrate and the second substrate are bonded together by the first surface film and the second surface film. The substrate processing system is A holding portion for holding the back surface of the first substrate, A laser irradiation unit that emits laser light, A transport unit for separating the second substrate from the first substrate, The control device has a program storage unit for storing the program, The substrate processing method is With the holding portion holding the first substrate, the laser irradiation portion irradiates the laser absorption layer with the laser light in a pulsed manner from the back side of the second substrate. A storage medium comprising the transport unit which, at the interface between the laser absorption layer and the second substrate, peels the second substrate from the first substrate and transfers the second device layer and the second surface film to the first substrate.

14. In the substrate processing method described above, the laser light is irradiated onto the laser absorption layer from the radially outer side toward the inner side, The storage medium according to claim 13, wherein the irradiation of the laser light is started between the outer peripheral edge of the second substrate and the outer peripheral edge of the laser absorption layer which is the bonding end between the first substrate and the second substrate in the polymerized substrate.

15. The substrate processing system is A rotating mechanism for rotating the holding part, It has a moving mechanism for moving the holding portion in the radial direction, The substrate processing method is The storage medium according to claim 13 or 14, comprising alternating between rotating the polymer substrate and moving the polymer substrate radially, thereby irradiating the laser absorption layer with the laser light in an annular manner.

16. The substrate processing system has a rotating mechanism for rotating the holding portion, In the substrate processing method described above, the polymerized substrate is rotated while the laser light is irradiated, The storage medium according to any one of claims 13 to 15, wherein the rotation speed of the polymerization substrate is faster when the laser light is irradiated inward compared to when it is irradiated radially outward of the laser absorption layer, and the frequency of the laser light irradiated radially outward of the laser absorption layer is greater than the frequency of the laser light irradiated inward.

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