Substrate 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] In the polymer substrate in which the first substrate and the second substrate are bonded, the technique according to the present disclosure appropriately transfers the device layer formed on the second substrate to the first substrate.

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 the first substrate and the second substrate are bonded. 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 with the first surface film and the second surface film. The substrate processing system includes a holding unit that holds the back surface of the first substrate, a laser irradiation unit that irradiates laser light, a transfer unit that peels the second substrate from the first substrate, a program storage unit that stores a program, and a control device having a computer that reads the program from the program storage unit and operates the program. The program is a program that operates on the computer of the control device that controls the substrate processing system so that the substrate processing system executes a substrate processing method. The substrate processing method includes irradiating the laser absorption layer with the laser light in a pulsed manner from the back surface side of the second substrate by the laser irradiation unit while the holding unit holds the first substrate, and peeling the second substrate from the first substrate at the interface between the laser absorption layer and the second substrate by the transfer unit to transfer the second device layer and the second surface film to the first substrate.

Effect of the Invention

[0006] According to the present disclosure, in a polymer substrate in which a first substrate and a second substrate are bonded, a device layer formed on the second substrate can be appropriately transferred to the first substrate.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Figure 16

Figure 17

Figure 18

Figure 19

Figure 20

Figure 21

Figure 22

Figure 23

Figure 24

Figure 25

Figure 26

Figure 27

Figure 28

Figure 29

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, has been 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 there is a wide range of choices for the laser light.

[0009] On the other hand, in the manufacturing process of semiconductor devices, a device layer formed on the surface of a substrate (such as a silicon substrate like a semiconductor) is transferred to another substrate. Silicon substrates generally have permeability to laser light in the NIR (near-infrared) region. However, since the absorption layer also has permeability to NIR laser light, the device layer may be damaged. Therefore, in order to perform laser lift-off in the manufacturing process of semiconductor devices, laser light in the FIR (far-infrared) region is used.

[0010] Generally, for example, a CO2 laser can be used to generate laser light with a wavelength in the FIR range. In the method described in Patent Document 1 mentioned above, by irradiating the peeling oxide film with a CO2 laser, peeling occurs at the interface between the peeling oxide film and the substrate.

[0011] Here, as a result of the inventors' intensive studies, it was found that peeling may not occur simply by irradiating with a CO2 laser. That is, it was found that the factor causing peeling is not the energy amount of the CO2 laser but the peak power (the maximum intensity of the laser light). For example, as shown in FIG. 1, when the CO2 laser is continuously oscillated (when a continuous wave is used), it is difficult to increase the peak power, and peeling may not occur. On the other hand, when the CO2 laser is pulsed (when a pulsed wave is used), the peak power can be increased, and peeling can be generated. In the present disclosure, the laser light obtained by oscillating the CO2 laser in a pulsed manner is a so-called pulsed laser, and its power repeats between 0 (zero) and the maximum value.

[0012] In addition, when the CO2 laser is continuously oscillated, the thermal effect is large, so stable laser lift-off cannot be performed, and there is also a risk that the device layer will be damaged by heat. Therefore, from this perspective as well, it is better to irradiate the CO2 laser in a pulsed manner.

[0013] As described above, in order to separate the substrate from the peeling oxide film (device layer), it is necessary to irradiate the peeling oxide film with a pulsed CO2 laser. However, in the method of Patent Document 1, no consideration is given to the pulsed laser, nor is there any suggestion thereof. Therefore, there is room for improvement in the conventional method for transferring a device layer.

[0014] 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. Hereinafter, a wafer processing system including a laser irradiation device as a substrate processing device according to the present embodiment and a wafer processing method as a substrate processing method will be described with reference to the drawings. In the present specification and drawings, elements having substantially the same functional configuration are denoted by the same reference numerals, and redundant description is omitted.

[0015] In the wafer processing system 1 according to the present embodiment described below, as shown in FIG. 2, processing is performed on a polymerized wafer T as a polymerized substrate in which a first wafer W1 as a first substrate and a second wafer W2 as a second substrate are joined. Hereinafter, in the first wafer W1, the surface on the side joined to the second wafer W2 is referred to as a front surface W1a, and the surface on the side opposite to the front surface W1a is referred to as a back surface W1b. Similarly, in the second wafer W2, the surface on the side joined to the first wafer W1 is referred to as a front surface W2a, and the surface on the side opposite to the front surface W2a is referred to as a back surface W2b.

[0016] The first wafer W1 is a semiconductor wafer such as a silicon substrate, for example. On the front surface W1a of the first wafer W1, a device layer D1 and a surface film F1 are laminated in this order from the front surface W1a side. The device layer D1 includes a plurality of 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 the surface film F1 may not be formed on the front 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 laminated 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 described later. For the laser absorption layer P, for example, an oxide film (SiO2 film) is used, but it is not particularly limited as long as it can absorb laser light. The device layer D2 and the surface film F2 are the same as the device layer D1 and the surface film F1 of the first wafer W1, respectively. Then, the surface film F1 of the first wafer W1 and the surface film F2 of the second wafer W2 are joined. 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 the 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 FIG. 3, the wafer processing system 1 has a configuration in which a loading / unloading block 10, a transfer block 20, and a processing block 30 are integrally connected. The loading / unloading block 10 and the processing block 30 are provided around the transfer block 20. Specifically, the loading / unloading block 10 is arranged on the negative Y-axis side of the transfer block 20. The laser irradiation device 31, which will be described later, of the processing block 30 is arranged on the negative X-axis side of the transfer block 20, and the cleaning device 32, which will be described later, is arranged on the positive X-axis side of the transfer block 20.

[0019] The loading / unloading block 10 is, for example, capable of loading and unloading a cassette Ct, Cw1, Cw2 that can each accommodate a plurality of polymer wafers T, a plurality of first wafers W1, and a plurality of second wafers W2 with the outside. The loading / unloading block 10 is provided with a cassette mounting table 11. In the illustrated example, the cassette mounting table 11 can mount a plurality of, for example, three cassettes Ct, Cw1, Cw2 in a row in the X-axis direction. Note that the number of cassettes Ct, Cw1, Cw2 mounted on the cassette mounting table 11 is not limited to this embodiment and can be arbitrarily determined.

[0020] The transfer block 20 is provided with a wafer transfer device 22 configured to be movable on a transfer path 21 extending in the X-axis direction. The wafer transfer device 22 has, for example, two transfer arms 23, 23 that hold and transfer the polymerized wafer T, the first wafer W1, and the second wafer W2. Each transfer arm 23 is configured to be movable in the horizontal direction, the vertical direction, around the horizontal axis, and around the vertical axis. Note that the configuration of the transfer arm 23 is not limited to this embodiment and can take any configuration. And the wafer transfer device 22 is configured to be able to transfer 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 described later.

[0021] The processing block 30 has 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. Note that 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 and clean the surface. Note that for cleaning the surface, a pressurized cleaning liquid may be used. Also, the cleaning device 32 may be configured to clean the back surface W1b together with the surface W1a side of the first wafer W1.

[0023] The above wafer processing system 1 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 for controlling the processing of the polymerized wafer T in the wafer processing system 1. Further, the program storage unit also stores a program for controlling the operation of the drive systems of the above-described various processing devices and transfer devices, etc., to realize the wafer processing described later in the wafer processing system 1. Note that the above program may be recorded on a computer-readable storage medium H and installed from the storage medium H into the control device 40.

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

[0025] As shown in FIGS. 4 and 5, the laser irradiation device 31 has a chuck 100 as a holding unit that holds the polymerized wafer T on the upper surface. The chuck 100 adsorbs and holds the entire back surface W1b of the first wafer W1. Note that the chuck 100 may adsorb and hold a part of the back surface W1b. The chuck 100 is provided with lift pins (not shown) for supporting and lifting the polymerized wafer T from below. The lift pins are inserted through through-holes (not shown) formed through the chuck 100 and are configured to be liftable.

[0026] The chuck 100 is supported by a slider table 102 via an air bearing 101. A rotation mechanism 103 is provided on the lower surface side of the slider table 102. The rotation mechanism 103 incorporates, for example, a motor as a drive source. The chuck 100 is configured to be rotatable around the θ-axis (vertical axis) by the rotation mechanism 103 via the air bearing 101. The slider table 102 is configured to be movable along a rail 105 provided on the base 106 and extending in the Y-axis direction by a movement mechanism 104 provided on the lower surface side thereof. Note that the drive source of the movement mechanism 104 is not particularly limited, and for example, a linear motor is used.

[0027] Above the chuck 100, a laser irradiation unit 110 is provided. The laser irradiation unit 110 includes a laser head 111, an optical system 112, and a lens 113. The laser head 111 oscillates 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 polymerization 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 is irradiated onto the laser absorption layer P. Note that the wavelength of the CO2 laser light is, for example, 8.9 μm to 11 μm. Further, the lens 113 is configured to be movable up and down by an elevating mechanism (not shown).

[0028] Also, above the chuck 100, a transfer pad 120 as a transfer unit is provided. The transfer pad 120 is configured to be movable up and down by an elevating mechanism (not shown). Further, the transfer pad 120 has an adsorption surface for the second wafer W2. Then, the transfer pad 120 transfers the second wafer W2 between the chuck 100 and the transfer arm 23. Specifically, after moving the chuck 100 to below the transfer pad 120 (the handover position with the transfer arm 23), the transfer pad 120 adsorbs and holds the back surface W2b of the second wafer W2 and peels it off from the first wafer W1. Subsequently, the peeled second wafer W2 is handed over from the transfer pad 120 to the transfer arm 23 and carried out from the laser irradiation device 31. Note that the transfer pad 120 may 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 FIG. 5, the transfer arm 23 accesses the transfer pad 120 from the positive X-axis side. However, the laser irradiation device 31 shown in FIG. 5 may be rotated 90 degrees counterclockwise, and the transfer arm 23 may access the transfer pad 120 from the negative Y-axis side.

[0030] When the overlapped wafer T is carried into the laser irradiation device 31, the overlapped wafer T is transferred from the transfer arm 23 to the lift pins, and the lift pins are lowered to place the overlapped wafer T on the chuck 100. When the peeled first wafer W1 is carried out of the laser irradiation device 31, the overlapped wafer T placed on the chuck 100 is lifted by the lift pins, and then transferred from the lift pins to the transfer arm 23.

[0031] Next, a description will be given of wafer processing performed using the wafer processing system 1 configured as described above. In this embodiment, a first wafer W1 and a second wafer W2 are bonded together in a bonding device (not shown) external to the wafer processing system 1 to form an overlapped wafer T in advance.

[0032] First, a cassette Ct containing a plurality of overlapping wafers T is placed on the cassette placement table 11 of the carry-in / out block 10.

[0033] Next, the overlapped wafer T is removed from the cassette Ct by the wafer transfer device 22 and transferred to the laser irradiation device 31. In the laser irradiation device 31, the overlapped wafer T is transferred from the transfer arm 23 to the lifting pins and is held by suction on the chuck 100. Next, the moving mechanism 104 moves the chuck 100 to a processing position. This processing position is a position where the laser irradiation unit 110 can irradiate the overlapped wafer T (laser absorption layer P) with laser light.

[0034] Next, as shown in Figures 6 and 7, the laser irradiating unit 110 irradiates the laser absorbing layer P, more specifically, the interface between the laser absorbing layer P and the second wafer W2 with pulsed laser light L (CO2 laser light). 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 in the laser absorbing layer P. Then, this laser light L causes peeling at the interface between the laser absorbing layer P and the second wafer W2. Note that the laser light L is almost entirely absorbed by the laser absorbing layer P and does not reach the device layer D2. This makes it possible to prevent damage to the device layer D2.

[0035] When irradiating the laser absorption layer P with the laser beam L, the chuck 100 (the laminated wafer T) is rotated by the rotation mechanism 103, and the chuck 100 is moved in the Y-axis direction by the movement mechanism 104. Then, the laser beam L is irradiated from the outside in the radial direction toward the inside of the laser absorption layer P, and as a result, it is irradiated in a spiral shape from the outside to the inside. The black arrow shown in FIG. 7 indicates the rotation direction of the chuck 100.

[0036] The irradiation start position of the laser beam L is preferably between the outer peripheral end Ea of the second wafer W2 and the bonding end Eb between the first wafer W1 and the second wafer W2 in the laminated wafer T. In such a case, for example, even when the centers of the first wafer W1 and the second wafer W2 are displaced and eccentric in the laminated wafer T, the eccentricity can be absorbed and the laser absorption layer P can be appropriately irradiated with the laser beam L.

[0037] In addition, as shown in FIG. 8, in the laser absorption layer P, the laser beam L may be irradiated in a concentric circular shape. However, in this case, since the rotation of the chuck 100 and the Y-direction movement of the chuck 100 are performed alternately, irradiating the laser beam L in a spiral shape as described above can shorten the irradiation time and improve the throughput.

[0038] Also, in the laser absorption layer P, the laser beam L may be irradiated from the inside to the outside in the radial direction. However, in this case, since the inside of the laser absorption layer P peels off first, the stress associated with the peeling is directed outward in the radial direction, and the portion where the laser beam L is not irradiated on the outside may also peel off. In this regard, when irradiating the laser beam L from the outside to the inside in the radial direction as described above, the stress associated with the peeling can be released to the outside, so that the control of the peeling becomes easier. Also, by appropriately controlling the peeling, it is possible to suppress the roughness of the peeling surface.

[0039] In addition, in this embodiment, when irradiating the laser absorption layer P with the laser beam L, the chuck 100 was rotated. However, the lens 113 may be moved to relatively rotate the lens 113 with respect to the chuck 100. Also, although the chuck 100 was moved in the Y-axis direction, the lens 113 may be moved in the Y-axis direction.

[0040] In this way, in the laser irradiation device 31, the laser absorption layer P is irradiated with the laser beam L. And since the laser beam L is irradiated in a pulsed manner, the peak power of the laser beam L can be increased. Therefore, as described with reference to FIG. 1 above, peeling can occur at the interface between the laser absorption layer P and the second wafer W2, and the second wafer W2 can be appropriately peeled from the laser absorption layer P.

[0041] Next, the moving mechanism 104 moves the chuck 100 to the delivery position. Then, as shown in FIG. 9(a), the back surface W2b of the second wafer W2 is adsorbed and held by the transfer pad 120. After that, with the transfer pad 120 adsorbing and holding the second wafer W2 as shown in FIG. 9(b), the transfer pad 120 is lifted to peel the second wafer W2 from the laser absorption layer P. At this time, as described above, peeling has occurred at the interface between the laser absorption layer P and the second wafer W2 due to the irradiation of the laser beam L, so the second wafer W2 can be peeled from the laser absorption layer P without applying a large load.

[0042] The peeled second wafer W2 is delivered from the transfer pad 120 to the transfer arm 23 of the wafer transfer device 22 and then conveyed to the cassette Cw2 on the cassette mounting table 11. Note that the second wafer W2 taken out from the laser irradiation device 31 may be conveyed to the cleaning device 32 before being conveyed to the cassette Cw2, and the surface W2a, which is the peeled surface, may be cleaned. In this case, the transfer pad 120 may invert the front and back surfaces of the second wafer W2 and deliver it to the transfer arm 23.

[0043] For the first wafer W1 held by the chuck 100, it is lifted from the chuck 100 by the lifting pins, transferred to the transfer arm 23, and then transferred to the cleaning device 32. In the cleaning device 32, the surface of the laser absorption layer P, which is the peeling surface, is scrubbed and cleaned. Note that in the cleaning device 32, the back surface W1b of the first wafer W1 may also be cleaned together with the surface of the laser absorption layer P. Alternatively, separate cleaning units for cleaning the surface of the laser absorption layer P and the back surface W1b of the first wafer W1 may be provided respectively.

[0044] After that, the first wafer W1 that has undergone all the processes is transferred by the wafer transfer device 22 to the cassette Cw1 on the cassette mounting table 11. Thus, a series of wafer processes in the wafer processing system 1 is completed.

[0045] According to the above embodiment, in the laser irradiation device 31, since the laser absorption layer P is irradiated with the laser light L in a pulsed manner, the peak power of the laser light L can be increased. As a result, peeling can occur at the interface between the laser absorption layer P and the second wafer W2. In addition, when the laser light L is irradiated in a pulsed manner, the thermal influence is smaller compared to the case of using a continuous wave, and stable laser lift-off can be performed. Therefore, the second wafer W2 can be appropriately peeled from the laser absorption layer P, and the device layer D2 can be transferred to the first wafer W1.

[0046] Here, in order to make the peeling between the first wafer W1 and the second wafer W2 uniform within the wafer surface, it is preferable to keep the interval at which the laser light L is irradiated, that is, the pulse interval, constant. However, when rotating the chuck 100 (the bonded wafer T) to keep the pulse interval constant, as the laser light L moves from the outer side to the inner side in the radial direction, the rotation speed of the chuck 100 increases. In such a case, when the rotation speed of the chuck 100 reaches the upper limit, as the irradiation position of the laser light L moves to the inner side in the radial direction, the interval between the laser lights L becomes smaller, and the laser lights L may overlap at the center. Therefore, it is necessary to adjust the irradiation interval of the laser light L. For example, there are the following two methods.

[0047] The first method is a method of controlling the rotation speed of the chuck 100. That is, when the irradiation position of the laser beam L is outside the radial direction of the laser absorption layer P, the rotation speed is slowed down, and when the irradiation position of the laser beam L is inside, the rotation speed is increased. Note that the specific adjustment of this rotation speed is arbitrarily set according to the frequency of the laser beam L. In such a case, the rotation speed of the chuck 100 can be made constant, and the interval for irradiating the laser beam L can be made constant.

[0048] The second method is a method of controlling the frequency of the laser beam L. That is, when the irradiation position of the laser beam L is outside the radial direction of the laser absorption layer P, the frequency is increased, and when the irradiation position of the laser beam L is inside, the frequency is decreased. Note that the specific adjustment of this frequency is arbitrarily set according to the rotation speed of the chuck 100. Even in such a case, the rotation speed of the chuck 100 can be made constant, and the interval for irradiating the laser beam L can be made constant.

[0049] In order to shorten the processing time (tact) of laser irradiation and improve the throughput, in the first method, it is preferable to use a laser beam L with a high frequency and maintain the rotation speed of the chuck 100.

[0050] Also, the first method and the second method described above may be used in combination. In such a case, on the outer side in the radial direction, while slowing down the rotation speed of the chuck 100, the frequency of the laser beam L is increased. On the other hand, on the inner side in the radial direction, while increasing the rotation speed of the chuck 100, the frequency of the laser beam L is decreased.

[0051] Here, when controlling the frequency of the laser beam L in the second method, 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 in consideration of the output and pulse waveform of the laser beam L. For example, when the energy of the laser beam L required to cause peeling on the outer and inner sides in the radial direction of the laser absorption layer P is the same, increasing the frequency of the laser beam L on the outer side increases the output, and decreasing the frequency of the laser beam L on the inner side decreases the output. Further, when changing the frequency of the laser beam L in the laser oscillator, the pulse waveform of the laser beam L also changes. Therefore, complex adjustment considering the output and pulse waveform of the laser beam L is required, and process control of the laser processing is difficult.

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

[0053] As shown in FIG. 10, the laser head 111 has a laser oscillator 130 that oscillates the laser beam in a pulsed manner. The frequency of the laser beam oscillated from the laser oscillator 130 is the maximum frequency that can be controlled by an acousto-optic modulator 131 described later. Note that the laser head 111 may have other devices of the laser oscillator 130, such as an amplifier.

[0054] The optical system 112 includes an acousto-optic modulator (AOM) 131 that deflects the laser beam from the laser oscillator 130 in different directions, and an attenuator 132 as an attenuator that attenuates the laser beam from the laser oscillator 130 and adjusts the output of the laser beam. The acousto-optic modulator 131 and the attenuator 132 are provided 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 a laser beam at high speed. As shown in FIG. 11 , when a laser beam L1 from a laser oscillator 130 is incident on the acousto-optic modulator 131, a voltage is applied to change the refractive index of the laser beam L1, thereby deflecting the laser beam L1 in different directions. Specifically, the deflection angle of the laser beam L1 can be controlled by adjusting the voltage. In this embodiment, for example, the laser beam L1 is deflected in two different directions, and the laser beam L2 in one direction is irradiated onto the laser absorption layer P, while the laser beam L3 in the other direction is not irradiated onto the laser absorption layer P. By controlling the deflection of the laser beams L2 and L3, the frequency of the laser beam L2 irradiated onto the laser absorption layer P can be adjusted.

[0056] In this case, the frequency of the laser light L2 irradiated onto the laser absorption layer P can be adjusted by thinning out pulses of the laser light L1 using the acousto-optic modulator 131. For example, if the redirection ratio of the laser light L2 and the laser light L3 relative to the laser light L1 is set to 100:0 at a certain timing, the laser light L1 becomes the laser light L2 as it is and is irradiated onto the laser absorption layer P. On the other hand, if the redirection ratio of the laser light L2 and the laser light L3 relative to the laser light L1 is set to 0:100 at another timing, the laser light L2 becomes 0 (zero), and the laser absorption layer P is not irradiated with the laser light L2. In this case, the frequency of the laser light L2 redirected by the acousto-optic modulator 131 shown in FIG. 12(b) can be adjusted relative to the frequency of the laser light L1 from the laser oscillator 130 shown in FIG. 12(a). Furthermore, since the frequency of the laser light L1 is the highest frequency that the acousto-optic modulator 131 can control as described above, the frequency of the laser light L2 can be adjusted arbitrarily. 12, the horizontal axis represents time, and the vertical axis represents the intensity of the laser light L2. That is, the density in the graph of FIG. 12 represents the frequency of the laser light L2.

[0057] Moreover, in this case, since the frequency of the laser beam L1 oscillated from the laser oscillator 130 is not changed, the pulse waveform of the laser beam L1 remains the same, and the pulse waveform of the laser beam L2 can also be made the same as that of the laser beam L1. Therefore, the frequency of the laser beam L2 can be easily adjusted, eliminating the need for the complicated conventional adjustments as described above, and facilitating the process control of the laser processing.

[0058] In the present embodiment, the acousto-optic modulator 131 is used as the optical element, but it is not limited thereto. For example, an electro-optic modulator (EOM) may be used as the optical element. Also, an optical deflector such as an acousto-optic deflector (AOD) or an electro-optic deflector (EOD) may be used.

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

[0060] Hereinafter, a specific example will be used for explanation. Note that the numerical values in this specific example are for illustration only, and the present disclosure is not limited to these numerical values. For example, in the outer and inner sides in the radial direction of the laser absorption layer P, the energy required for peeling is 400 μJ. The required frequency of the laser beam L2 on the outer side in the radial direction of the laser absorption layer P is 100 kHz, and the required frequency of the laser beam on the inner side is 50 kHz. The frequency of the laser beam L1 from the laser oscillator 130 is 100 kHz, and the output is 40 W.

[0061] In such a case, for the radially outer side of the laser absorption layer P, the acoustic-optic modulator 131 does not decimate the pulses of the laser light L1 from the laser oscillator 130. Then, the frequency of the laser light L2 irradiated on the laser absorption layer P can be set to the same 100 kHz as the frequency of the laser light L1. Also, the output of the laser light L2 also becomes the same 40 W as the output of the laser light L1. And the energy of the laser light L2 becomes 400 μJ (= 40 W / 100 kHz), and peeling can be appropriately performed.

[0062] On the other hand, for the radially inner side of the laser absorption layer P, the acoustic-optic modulator 131 decimates the pulses of the laser light L1 from the laser oscillator 130 by half. Then, the frequency of the laser light L2 irradiated on the laser absorption layer P can be set to 50 kHz, which is half of the frequency of the laser light L1. Also, due to this decimation of the laser light L1, the output of the laser light L2 also becomes 20 W, which is half of the output of the laser light L1. And the energy of the laser light L2 becomes 400 μJ (= 20 W / 50 kHz), and peeling can be appropriately performed.

[0063] In this way, according to the frequency and irradiation position of the laser light L2, the rotation speed of the chuck 100 is controlled so that the pulse interval becomes constant. And at the center of the laser absorption layer P, the maximum rotation speed of the chuck 100 is maintained, and instead of the acoustic-optic modulator 131 at the maximum rotation speed, the frequency of the laser light L2 is adjusted. Thereby, laser processing that maintains the high rotation speed of the chuck 100 and the high frequency of the laser light L2 to the maximum can be performed, and high-throughput laser processing can be realized.

[0064] Moreover, 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 does not change, and the pulse waveform of the laser light L2 can also 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, and continuous seamless processing becomes possible. As a result, the process control of the laser processing becomes easy, and a stable process can be realized.

[0065] In this embodiment, the output of the laser beam L1 from the laser oscillator 130 was 40 W, so there was no need to adjust the output to achieve the energy of 400 μJ required for delamination. In this regard, if the output of the laser beam L1 is 50 W, for example, the output of the laser beam L1 can be adjusted by attenuating the output of the laser beam L1 by 20% in the attenuator 132.

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

[0067] In the laser irradiation unit 110, after the frequency and output of the laser light L2 are adjusted by the acousto-optic modulator 131, the output can be finely adjusted by the attenuator 132. Here, the output of the laser light L1 oscillated from the laser oscillator 130 may vary due to individual differences in the laser oscillator 130. The attenuator 132 can adjust such output variations. Furthermore, when the output of the laser light L1 from the laser oscillator 130 is monitored over time, the output can be adjusted by feedback-controlling the attenuator 132. From the viewpoint of finely adjusting the output of the laser light L2 by 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 FIG. 10 .

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

[0069] In the above embodiment, the laser beam L is irradiated on the laser absorption layer P in a spiral or concentric shape, but the irradiation pattern of the laser beam L is not limited to this. Also, the configuration of the apparatus corresponding to such various irradiation patterns is not limited to the laser irradiation apparatus 31 of the above embodiment. In the laser irradiation apparatus 31, the chuck 100 is rotatable about the θ axis and movable in one axis (Y axis) direction, but it may be moved in two axes (X axis and Y axis).

[0070] The laser irradiation apparatus 200 shown in FIGS. 15 and 16 is an apparatus that moves the chuck 100 in two axes (X axis and Y axis). The laser irradiation apparatus 200 has a chuck 210 as a holding unit that holds the polymerized wafer T on the upper surface. The chuck 210 adsorbs and holds the back surface W1b of the first wafer W1. The chuck 210 is provided with lift pins (not shown) for supporting and lifting the polymerized wafer T from below. The lift pins are inserted through through holes (not shown) formed through the chuck 210 and are configured to be movable up and down.

[0071] The chuck 210 is supported by a slider table 212 via an air bearing 211. A rotation mechanism 213 is provided on the lower surface side of the slider table 212. The rotation mechanism 213 incorporates, for example, a motor as a drive source. The chuck 210 is configured to be rotatable about the θ-axis (vertical axis) via the air bearing 211 by the rotation mechanism 213. The slider table 212 is configured to be movable along a rail 215 provided on a moving stage 216 and extending in the Y-axis direction by a moving mechanism 214 provided on the lower surface side thereof. Note that the drive source of the moving mechanism 214 is not particularly limited, and for example, a linear motor is used.

[0072] The moving stage 216 is configured to be movable along a rail 217 provided on a base 218 and extending in the X-axis direction by a moving mechanism (not shown) provided on the lower surface side thereof. Note that the drive source of the moving mechanism is not particularly limited, and for example, a linear motor is used. With such a configuration, the chuck 210 is rotatable about the θ-axis and movable in the X-axis and Y-axis directions.

[0073] Above the chuck 210, a laser irradiation unit 220 is provided. The laser irradiation unit 220 includes a laser head 221, an optical system 222, and a lens 223. The laser head 221 oscillates 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 and irradiates the polymer wafer T held by the chuck 210 with the laser light L, which is, for example, CO2 laser light. Note that the lens 223 is configured to be movable up and down by a lifting mechanism (not shown).

[0074] For the laser head 221, for example, a galvano is used. Inside the laser head 221, a plurality of galvano mirrors (not shown) are arranged. Also, an f-θ lens is used for the lens 223. With such a configuration, the laser beam L input to the laser head 221 is reflected by the galvano mirror, propagated through the optical system 222 to the lens 223, transmitted through the second wafer W2, and irradiated onto the laser absorption layer P. Then, by adjusting the angle of the galvano mirror, the laser beam L can be scanned across the laser absorption layer P.

[0075] Also, above the chuck 210, a transfer pad 230 as a transfer unit is provided. The transfer pad 230 is configured to be movable up and down by a lifting mechanism (not shown). Note that the configuration of the transfer pad 230 is the same as that of the transfer pad 120 in the above embodiment.

[0076] In such a laser irradiation device 200, the polymerization wafer T is transferred from the transfer arm 23 to the lifting pins and adsorbed and held by the chuck 210. Subsequently, the chuck 210 is moved to the processing position by the movement mechanism 214 and the movement stage 216. This processing position is a position where the laser beam L can be irradiated from the laser irradiation unit 220 onto the polymerization wafer T (laser absorption layer P).

[0077] Next, as shown in FIG. 17, the laser absorption layer P is irradiated with the laser beam L in a pulsed manner from the laser irradiation unit 220. At this time, the laser beam L passes through the second wafer W2 from the back surface W2b side of the second wafer W2 and is absorbed in the laser absorption layer P.

[0078] When irradiating the laser absorption layer P with the laser beam L, the laser beam L is scanned within a predetermined scan range A (the rectangular area in FIG. 17). Next, the chuck 210 is moved in the X-axis direction with the irradiation of the laser beam L stopped. In this way, the irradiation and scanning of the laser beam L and the movement of the chuck 210 are repeated to irradiate the laser beam L in a row in the X-axis direction. Next, the chuck 210 is moved so as to be shifted in the Y-axis direction, and the irradiation and scanning of the laser beam L and the movement of the chuck 210 are repeated in the same manner as described above to irradiate the laser beam L in a row in the X-axis direction. Then, the laser beam L is irradiated onto the laser absorption layer P.

[0079] In this embodiment, when irradiating the laser absorption layer P with the laser beam L, the chuck 210 is moved in the X-axis direction and the Y-axis direction. However, the lens 223 may be moved to relatively move the lens 223 with respect to the chuck 210.

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

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

[0082] In this embodiment, there may be a plurality of laser irradiation units 220. In such a case, a plurality of laser beams L can be irradiated onto the laser absorption layer P, the processing time can be shortened, and the throughput can be further improved.

[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 FIG. 18, in a row in the X-axis direction, the irradiation and scanning of the laser beam L may be performed while moving the chuck 210. Then, after irradiating the laser beam L in a row in the X-axis direction, the chuck 210 is moved so as to be shifted in the Y-axis direction, and the laser beam L is irradiated onto the laser absorption layer P.

[0084] Also in this embodiment, the same effects as those of the above embodiment can be obtained. That is, since the laser beam L is pulsed onto the laser absorption layer P, appropriate peeling can occur at the interface between the laser absorption layer P and the second wafer W2. Moreover, in a row in the X-axis direction, since the irradiation and scanning of the laser beam L are not stopped, the processing time of the laser irradiation can be shortened and the throughput can be further improved.

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

[0086] When rotating the chuck 210 (the laminated wafer T) as described above, in order to make the pulse interval constant, the rotation speed of the chuck 210 increases as the laser beam L moves from the outer diameter side to the inner diameter side. Therefore, in the above embodiment, at least the rotation speed or frequency of the chuck 210 was controlled to adjust the irradiation interval of the laser beam L.

[0087] On the other hand, as shown in FIG. 19, at the outer peripheral portion of the laser absorption layer P, while rotating the chuck 210, the chuck 210 is moved from the outer diameter side to the inner diameter side, and the laser beam L is irradiated in a spiral shape. Then, when the rotation speed of the chuck 210 reaches the upper limit, the rotation of the chuck 210 is stopped at the central portion of the laser absorption layer P, and scanning is performed while irradiating the laser beam L in the scan range A. Although the scan range A is illustrated as a rectangular shape, the shape of the scan range A is not limited to this. For example, the scan range A may be a circular shape.

[0088] By changing the irradiation pattern of the laser beam L between the outer peripheral portion and the central portion of the laser absorption layer P in this way, it is possible to prevent the laser beams L from overlapping and to make the interval at which the laser beam L is irradiated, that is, the pulse interval, constant. As a result, the separation of the first wafer W1 and the second wafer W2 can be uniformly performed within the wafer surface.

[0089] In addition, when the irradiation range of the laser beam L of the laser irradiation unit 220 is wide, for example, when the irradiation range is equal to or larger than the diameter of the laser absorption layer P, the laser beam L may be irradiated all at once to the entire surface of the laser absorption layer P.

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

[0091] As shown in FIG. 21, the guide portion 240 guides the superposed wafers T with respect to the chuck 100. The guide portion 240 has a vertical portion 241 provided so as to extend vertically upward from the chuck 100, and an inclined portion 242 provided so that the diameter expands upward from the vertical portion 241. The inner diameter of the vertical portion 241 is slightly larger than the diameter of the superposed wafer T. Then, the superposed wafer T disposed above the chuck 100 is centered by the inclined portion 242, further guided by the vertical portion 241, and held by the chuck 100.

[0092] As shown in FIGS. 22 and 23, the holding member 250 extends vertically upward from the upper surface of the chuck 100 and holds the side surface of the second wafer W2. The holding members 250 are arranged at a plurality of locations, for example, three locations, on the concentric circles of the chuck 100. The holding member 250 is configured to be able to move forward and backward so as to be in contact with or separated from the second wafer W2 by a moving mechanism 251. Further, the holding member 250 is configured to be rotatable integrally with the chuck 100. By holding the second wafer W2 with the holding member 250, displacement and slipping of the second wafer W2 can be prevented. Note that a notch portion 233 is formed at a corresponding position of the holding member 250 in the guide portion 240, and the holding member 250 moves through the notch portion 233 so as not to interfere with the guide portion 240.

[0093] In this embodiment, both the guide portion 240 and the holding member 250 are provided, but only the guide portion 240 may be provided, or only the holding member 250 may be provided. When only the guide portion 240 is provided, displacement and slipping of the second wafer W2 can be suppressed by the vertical portion 241. In particular, when the gap between the vertical portion 241 and the second wafer W2 is within the allowable range of displacement, the guide portion 240 is useful. However, providing both the guide portion 240 and the holding member 250 enhances the effect of centering the stacked wafer T and preventing displacement and slipping of the second wafer W2.

[0094] In such a case, when the stacked wafer T is held by the chuck 100 at the delivery position, the three holding members 250 are retracted to positions where they do not contact the second wafer W2. Then, after moving the chuck 100 holding the stacked wafer T to the processing position, the three holding members 250 are moved to positions where they contact the side surface of the second wafer W2, and the second wafer W2 is held by these holding members 250.

[0095] Here, if the guide section 240 or the holding member 250 were not present, when the laser light L was irradiated spirally from the outside to the inside in the radial direction of the laser absorbing layer P, as the peeling progressed, centrifugal force would act on the second wafer W2 because the chuck 100 was rotating, causing the second wafer W2 to shift from the laser absorbing layer P, and there was a risk that the laser light L would be irradiated to a location other than the processing target position during laser processing. There was also a possibility that the peeled second wafer W2 would slide off. In this regard, in this embodiment, the second wafer W2 is held by the holding member 250, so that such shifting or sliding off of the second wafer W2 can be prevented.

[0096] Next, after irradiation with the laser light L, the second wafer W2 is held by the holding member 250 when the chuck 100 is moved to the delivery position. Here, an inertial force acts on the second wafer W2 while the chuck 100 is moving, and the second wafer W2 may be displaced from the laser absorption layer P. In such a case, when the back surface W2b of the second wafer W2 is subsequently sucked and held by the transfer pad 120, the second wafer W2 cannot be held in an appropriate position. Therefore, in this embodiment, the second wafer W2 is held by the holding member 250 even while the chuck 100 is moving, preventing the second wafer W2 from being displaced.

[0097] The configuration of the holding member that holds the second wafer W2 is not limited to the configuration of the holding member 250. For example, the holding member may hold the second wafer W2 from the sides thereof so as to sandwich the top and side surfaces of the second wafer W2. The holding member may also hold the second wafer W2 from the middle of the laser processing. If the holding member is made of a material that transmits the laser light L, such as silicon, it may hold the top surface of the second wafer W2.

[0098] The wafer processing system 1 of the above embodiment had the cleaning device 32. However, the wafer processing system 1 may further have an etching device (not shown). The etching device etches the surface W1a of the first wafer W1 after separation, specifically, the surface of the laser absorption layer P. For example, after scrub cleaning 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, and the surface is wet-etched. Also, the wafer processing system 1 may have either the cleaning device 32 or the etching device.

[0099] Further, the wafer processing system 1 of the above embodiment may have a CMP device (not shown). In the CMP device, the surface W1a of the first wafer W1 after separation, specifically, the surface of the laser absorption layer P is subjected to CMP (Chemical Mechanical Polishing) processing. For example, after scrub cleaning the surface of the laser absorption layer P with the cleaning device 32, CMP processing is performed on the surface of the laser absorption layer P to planarize the surface of the laser absorption layer P. Note that the CMP device may be provided outside the wafer processing system 1.

[0100] In the above embodiment, the laser beam L was irradiated on the interface between the laser absorption layer P and the second wafer W2 to separate the second wafer W2 from the laser absorption layer P. However, for example, as shown in FIG. 24, the separation may be performed so that the laser absorption layer P remains on the second wafer W2.

[0101] In such a case, in the laser irradiation device 31, as shown in FIG. 24(a), the laser beam L is pulsed and irradiated from the laser irradiation unit 110 onto the interface between the laser absorption layer P and the device layer D2. Then, due to this laser beam L, separation occurs at the interface between the laser absorption layer P and the device layer D2.

[0102] The adjustment of the absorption position of the laser light L, i.e., the adjustment of the peeling position of the laser absorbing layer P, is performed by controlling the energy density of the laser light L required to peel off the laser absorbing layer P according to the film type of the laser absorbing layer P. For example, the energy density of the laser light L can be adjusted by adjusting the focus numerical aperture (NA) of the laser irradiation unit 110, changing the focus position of the laser light L, changing the original output of the laser light L, etc.

[0103] Next, with the back surface W2b of the second wafer W2 being held by suction on the transfer pad 120, the transfer pad 120 is raised as shown in FIG. 24(b) to peel off the laser absorption layer P from the device layer D2.

[0104] This embodiment can also achieve the same effects as the above-described embodiment. That is, since the laser light L is irradiated to the laser absorbing layer P in pulses, the peak power of the laser light L can be increased, and as a result, appropriate delamination can be caused at the interface between the laser absorbing layer P and the device layer D2. Moreover, the laser absorbing layer P remaining on the second wafer W2 is an oxide film (SiO2 film), and this laser absorbing layer P can be used as an oxide film (insulating film) when fabricating TSVs (Through-Silicon Vias) on the second wafer W2 in a subsequent semiconductor manufacturing process, for example.

[0105] In this embodiment, the surface of the laser absorption layer P on the second wafer W2 after separation may be scrubbed and then subjected to CMP processing using the above-mentioned CMP device. In this case, the surface of the laser absorption layer P can be flattened. As described above, it can be appropriately used as an oxide film (insulating film) when fabricating TSVs.

[0106] In the above embodiment, the case where the overlapped wafer T shown in Fig. 2 is processed has been described, but the processing target is not limited to this. Hereinafter, the case where different types of overlapped wafer T are processed will be described with reference to Figs. 25 to 28.

[0107] A case of processing the polymerized wafer T shown in FIG. 25 will be described. As shown in FIG. 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, Si which is the second wafer W2, the SiO2 film which is the laser absorption layer P1, and Si which is the Si film S are laminated in this order. Note that, as long as it peels at the interface with the Si film S, a film other than the oxide film (SiO2 film), for example, silicon germanium (SiGe) or germanium (Ge) may be used for the laser absorption layer P1.

[0108] Next, as shown in FIG. 25(b), the device layer D2 and the 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 by a normal substrate process (FEOL) or a wiring process (BEOL).

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

[0110] Next, in the laser irradiation device 31 of the wafer processing system 1, as shown in FIG. 25(d), laser light L is pulsed and irradiated from the laser irradiation unit 110 to the interface between the laser absorption layer P1 and the Si film S. Then, peeling 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 back surface W2b of the second wafer W2 adsorbed and held by the transfer pad 120, as shown in FIG. 25(e), the transfer pad 120 is raised to peel the laser absorption layer P1 from the Si film S.

[0112] Note that also in this embodiment, similar to the case where the peeling position of the laser absorption layer P1 is shown in FIG. 24, the light absorption position of the laser light L, that is, 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.

[0113] The case of processing the polymerized wafer T shown in FIG. 26 will be described. As shown in FIGS. 26(a) and (b), between the second wafer W2 and the device layer D2, a laser absorption layer P2 made of silicon germanium (SiGe) and a Si film S made of Si are laminated in order from the second wafer W2 side.

[0114] Next, as shown in FIG. 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 FIG. 26(c), the first wafer W1 and the second wafer W2 are bonded. A device layer D1 and a surface film F1 are formed on the surface W1a of the first wafer W1, and the surface film F1 and the surface film F2 are bonded.

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

[0117] Next, with the back surface W2b of the second wafer W2 adsorbed and held by the transfer pad 120, as shown in FIG. 26(e), the transfer pad 120 is raised to peel the laser absorption layer P2 from the Si film S. In this embodiment as well, similar to the case where the peeling position of the laser absorption layer P1 is shown in FIG. 24, the light absorption position of the laser light L, that is, 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 P2.

[0118] The case of processing the polymerized wafer T shown in FIG. 27 will be described. As shown in FIGS. 27(a) and (b), between the second wafer W2 and the device layer D2, 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 laminated in order from the second wafer W2 side.

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

[0120] Next, as shown in FIG. 27(e), the first wafer W1 and the second wafer W2 are bonded. 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 the surface film F2 are bonded.

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

[0122] Next, with the back surface W2b of the second wafer W2 adsorbed and held by the transfer pad 120, as shown in FIG. 27(e), the transfer pad 120 is raised to peel the second wafer W2 from the laser absorption layer P3.

[0123] A case of processing the polymerized wafer T shown in FIG. 28 will be described. The polymerized wafer T has a structure in which Ge-pMOS is laminated on Si-nMOS. As shown in FIG. 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 FIG. 28(b), the first wafer W1 and the second wafer W2, which is Ge-pMOS, are bonded. 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 laminated in this order from the second wafer W2 side.

[0125] Next, as shown in FIG. 28(c), the first wafer W1 and the second wafer W2 are bonded. Specifically, this surface film F1 and the surface film F2 are bonded.

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

[0127] Next, with the back surface W2b of the second wafer W2 adsorbed and held by the transfer pad 120, the transfer pad 120 is raised as shown in FIG. 28(e) to peel the laser absorption layer P4 from the device layer D2. Also in this embodiment, similar to the case shown in FIG. 24 for the peeling position of the laser absorption layer P1, the light absorption position of the laser light L, that is, the peeling position of the laser absorption layer P1, may be adjusted to cause delamination at the interface between the second wafer W2 and the laser absorption layer P4.

[0128] Any of the processing targets shown in FIGS. 25 to 28 above can enjoy the same effects as those of the above embodiment.

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

[0130] In such a case, the laser light L emitted from the laser irradiation unit 110 passes through the second wafer W2 and is almost entirely absorbed in the laser absorption layer P. However, even if there is laser light L that could not be completely absorbed, it is reflected by the reflective film R. As a result, the laser light L does not reach the device layer D2, and it is possible to reliably prevent the device layer D2 from being damaged.

[0131] In addition, the laser beam L reflected by the reflection 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 this time should be considered as illustrative in all respects and not restrictive. The above embodiments may be omitted, replaced, or changed in various forms without departing from the scope and gist of the appended claims.

Description of Reference Numerals

[0133] 31 Laser irradiation device 100 Chuck 110 Laser irradiation unit 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 a second substrate to a first substrate in a polymerized substrate in which the first substrate and the second substrate are joined, comprising: 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 joined with the first surface film and the second surface film; A holding unit that holds the back surface of the first substrate; A laser irradiation unit that irradiates laser light; A transfer unit that peels the second substrate from the first substrate; A program storage unit that stores a program; A control device having a computer that reads the program from the program storage unit and operates the program; and The program is A program that operates on a computer of the control device that controls the substrate processing system so that the substrate processing system executes a substrate processing method, The substrate processing method is While the holding unit holds the first substrate, the laser irradiation unit irradiates the laser absorption layer with the laser light in a pulsed manner from the back surface side of the second substrate; The transfer unit peels the second substrate from the first substrate at the interface between the laser absorption layer and the second substrate, and transfers the second device layer and the second surface film to the first substrate. A substrate processing system.

2. In the substrate processing method, the laser light is irradiated onto the laser absorption layer from the outside in the radial direction toward the inside, The substrate processing system according to claim 1, wherein irradiation of the laser light is started from between an outer peripheral end of the second substrate and an outer peripheral end of the laser absorption layer that is a joining end of the first substrate and the second substrate in the polymerized substrate.

3. A rotation mechanism for rotating the holding unit; A moving mechanism for moving the holding unit in the radial direction; and 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 in the radial direction, and irradiating the laser absorption layer with the laser light in an annular shape.

4. The substrate processing system according to any one of claims 1 to 3, further comprising a cleaning device that cleans the first substrate from which the second substrate has been peeled.

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

7. Having a rotation mechanism for rotating the holding part, In the substrate processing method, irradiating the laser light while rotating the polymerized substrate, The rotation speed of the polymerized substrate is higher when the laser light is irradiated to the inner side than when it is irradiated to the outer side in the radial direction of the laser absorption layer, and the frequency of the laser light irradiated to the outer side in the radial direction of the laser absorption layer is higher than the frequency of the laser light irradiated to the inner side. The substrate processing system according to any one of claims 1 to 6.

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

9. A program that operates on a computer of a control device that controls the substrate processing system so that the substrate processing system executes a substrate processing method of transferring a device layer formed on the second substrate to the first substrate in a polymerized substrate in which the first substrate and the 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 joined at the first surface film and the second surface film, The substrate processing system is, A holding part for holding the back surface of the first substrate, A laser irradiation part for irradiating laser light, A transfer part for peeling the second substrate from the first substrate, The control device having a program storage part for storing the program, The substrate processing method is, While the holding part holds the first substrate, the laser irradiation part irradiates the laser absorption layer with the laser light in a pulsed manner from the back surface side of the second substrate, The transfer part peels the second substrate from the first substrate at the interface between the laser absorption layer and the second substrate, and transfers the second device layer and the second surface film to the first substrate. A program having.

10. In the substrate processing method, the laser light is irradiated onto the laser absorption layer from the outside in the radial direction, The program according to claim 9, wherein the irradiation of the laser light is started from between the outer peripheral end of the second substrate and the outer peripheral end of the laser absorption layer which is the bonding end of the first substrate and the second substrate in the polymerized substrate.

11. The substrate processing system, A rotation mechanism for rotating the holding part, And a moving mechanism for moving the holding part in the radial direction, The substrate processing method, The program according to claim 9 or 10, comprising alternately rotating the polymerized substrate and moving the polymerized substrate in the radial direction, and irradiating the laser light in an annular shape onto the laser absorption layer.

12. The substrate processing system has a rotation mechanism for rotating the holding part, In the substrate processing method, the laser light is irradiated while rotating the polymerized substrate, The rotation speed of the polymerized substrate is faster when the laser light is irradiated to the inner side than when it is irradiated to the outer side in the radial direction of the laser absorption layer, and the frequency of the laser light irradiated to the outer side in the radial direction of the laser absorption layer is higher than the frequency of the laser light irradiated to the inner side. The program according to any one of claims 9 to 11.

13. A computer-readable storage medium storing a program that operates on a computer of a control device that controls the substrate processing system so that the substrate processing system executes a substrate processing method of 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 joined at the first surface film and the second surface film, The substrate processing system, 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, And the control device having a program storage part for storing the program, The substrate processing method, With the holding part holding the first substrate, the laser irradiation part 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: peeling the second substrate from the first substrate at the interface between the laser absorption layer and the second substrate by the transfer part, and transferring the second device layer and the second surface film to the first substrate.

14. In the substrate processing method, the laser light is irradiated onto the laser absorption layer from the outside in the radial direction towards the inside. The storage medium according to claim 13, wherein the irradiation of the laser light is started from between the outer peripheral end of the second substrate and the outer peripheral end 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 includes a rotation mechanism for rotating the holding part, and a movement mechanism for moving the holding part in the radial direction. The substrate processing method includes alternately rotating the polymerized substrate and moving the polymerized substrate in the radial direction, and irradiating the laser absorption layer with the laser light in an annular shape. The storage medium according to claim 13 or 14.

16. The substrate processing system has a rotation mechanism for rotating the holding part. In the substrate processing method, the laser light is irradiated while rotating the polymerized substrate. The rotation speed of the polymerized substrate is faster when the laser light is irradiated to the inside than when it is irradiated to the outside in the radial direction of the laser absorption layer, and the frequency of the laser light irradiated to the outside in the radial direction of the laser absorption layer is higher than the frequency of the laser light irradiated to the inside. The storage medium according to any one of claims 13 to 15.

Images