Method and apparatus for processing bonded wafers

Abstract

To provide a method and apparatus for processing bonded wafers that can improve productivity. [Solution] The present invention relates to a method for transferring a first device to a second wafer by peeling off the first substrate side from a bonded wafer (300) formed by bonding the first device layer of a first wafer (100), which has a first device layer (130) comprising a first device (131) and an insulating layer (135) formed on the surface (111) side of a first substrate (110) in that order from the surface. The method involves a deformation step in which the first substrate is deformed so that the position differs in a direction intersecting the plane direction on one outer circumference and the other central side of the first substrate, and a peeling step in which, after the deformation step, the first substrate is peeled off, leaving the first device on the second wafer.

Description

Technical Field

[0001] The present invention relates to a processing method and a processing apparatus for a bonded wafer, which transfers devices from one wafer to another wafer. Background Art

[0002] Patent Document 1 discloses a method in which two wafers are bonded via a bonding film to form a bonded wafer, one wafer of the bonded wafer is ground, and devices on the one wafer are transferred to the other wafer. In the grinding processing performed by this method, approximately 10 μm of the wafer may remain, resulting in an increased thickness of the stacked wafer after device transfer. In addition, grinding processing of the wafer often removes approximately 760 μm, which causes the problem of prolonged processing time.

[0003] Here, Patent Document 2 discloses a method of forming a release layer in a buffer layer by laser beam to separate one wafer. In Patent Document 2, the grinding processing performed in Patent Document 1 can be omitted, thereby shortening the processing time. Prior Art Documents Patent Documents

[0004] Patent Document 1 Japanese Unexamined Patent Publication No. 2024-062595 Patent Document 2 Japanese Unexamined Patent Publication No. 2021-006352 Summary of the Invention Problems to be Solved by the Invention

[0005] However, in Patent Document 2, after separating one wafer, a predetermined thickness of the one wafer remains on the device side of the other wafer to which the devices have been transferred. For this reason, it is necessary to perform polishing processing to flatten the separation-side surface of the other wafer, or etching to remove the remaining portion of the one wafer on the other wafer, which causes the problem of reduced productivity.

[0006] This invention has been made in view of the above, and one of its objectives is to provide a method and apparatus for processing bonded wafers that can improve productivity. [Means for solving the problem]

[0007] A method for processing a bonded wafer according to one aspect of the present invention is a method for processing a bonded wafer in which a first device layer having a first device and an insulating film formed in order from the surface on the surface side of a first substrate is bonded to a second wafer, and at least the first substrate is peeled off from the bonded wafer and the first device is transferred to the second wafer, comprising: a deformation step of deforming at least the first substrate such that the positions of one side of the first substrate in the planar direction and the other side are different in a direction intersecting the planar direction; and a peeling step of peeling off at least the first substrate after the deformation step, leaving the first device on the second wafer.

[0008] A processing apparatus according to one aspect of the present invention is a processing apparatus for peeling off a first substrate from a bonded wafer, which is formed by bonding a first wafer and a second wafer, a first device layer having a first device and an insulating film formed in order from the surface on the surface side of a first substrate, and transferring the first device to the second wafer, comprising: a chuck table for holding the second wafer of the bonded wafer; a deformation unit for deforming at least a portion of the first substrate of the first wafer of the bonded wafer; and a peeling unit for peeling off the deformed first substrate. [Effects of the Invention]

[0009] According to the present invention, the first substrate of the first wafer can be peeled off from the bonded wafer, eliminating the need for polishing to create a flat surface after peeling, thereby improving productivity. [Brief explanation of the drawing]

[0010] [Figure 1] Figures 1A to 1C are explanatory diagrams of the deformation process in the first embodiment. [Figure 2]Figures 2A and 2B are explanatory diagrams of the peeling process in the first embodiment. [Figure 3] Figures 3A to 3C are explanatory diagrams of the deformation process in the second embodiment. [Figure 4] Figures 4A and 4B are explanatory diagrams of the deformation process in the third embodiment. [Figure 5] Figures 5A and 5B are explanatory diagrams of the deformation process in the fourth embodiment. [Figure 6] Figures 6A and 6B are explanatory diagrams of the deformation process in the fifth embodiment. [Figure 7] Figures 7A to 7C are explanatory diagrams of the deformation process in the sixth embodiment. [Figure 8] Figure 8A is an explanatory diagram of the surface heating process in the seventh embodiment, and Figures 8B and 8C are explanatory diagrams of the cooling process in the seventh embodiment. [Figure 9] Figures 9A and 9B are explanatory diagrams of the deformation process in the eighth embodiment. [Figure 10] Figure 10A is an explanatory diagram of the lattice defect layer formation process in the ninth embodiment, and Figures 10B and 10C are explanatory diagrams of the deformation process in the ninth embodiment. [Figure 11] This is an explanatory diagram of the deformation process in the tenth embodiment. [Figure 12] Figures 12A to 12C are explanatory diagrams of the deformation process in the eleventh embodiment. [Figure 13] Figures 13A to 13C are explanatory diagrams of the deformation process in the twelfth embodiment. [Figure 14] Figures 14A and 14B are explanatory diagrams of the deformation process in the thirteenth embodiment. [Figure 15] Figure 15A is an explanatory diagram of the lattice defect layer formation process in the 14th embodiment, and Figures 15B and 15C are explanatory diagrams of the deformation process in the 14th embodiment. [Figure 16] Figures 16A and 16B are explanatory diagrams of the peeling process in a modified example. [Mode for Carrying Out the Invention]

[0011] [First Embodiment] Hereinafter, a method for processing a bonded wafer according to a first embodiment will be described with reference to the accompanying drawings. FIGS. 1A to 1C are explanatory diagrams of a deformation step, and FIGS. 2A and 2B are explanatory diagrams of a peeling step, respectively. It should be noted that the steps shown in each drawing of the first embodiment are merely an example, and the present invention is not limited to this configuration. Further, in each drawing including FIG. 1, hatching in a cross-section of a first substrate 110 described later is omitted.

[0012] First, before describing each step, a bonded wafer 300 to be processed will be described with reference to FIG. 1A. The bonded wafer 300 is formed by bonding a disk-shaped first wafer 100 and a disk-shaped second wafer 200 together.

[0013] The first wafer 100 includes a front surface 101 and a back surface 102 which are surfaces orthogonal to the thickness direction, and the front surface 101 is disposed facing downward in FIG. 1A, and the back surface 102 is disposed facing upward in FIG. 1A. Further, the second wafer 200 includes a front surface 201 and a back surface 202 which are surfaces orthogonal to the thickness direction, and the front surface 201 is disposed facing upward in FIG. 1A, and the back surface 202 is disposed facing downward in FIG. 1A.

[0014] The first wafer 100 includes a first substrate 110 made of silicon, and a first device layer 130 formed on a front surface 111 side which is one surface in the thickness direction of the first substrate 110. The back surface 102 of the first wafer 100 is formed by a back surface 112 of the first substrate 110.

[0015] The first device layer 130 comprises a plurality of first devices 131, a first surface film 132 formed on the surfaces of the plurality of first devices 131 as a bonding film, and an insulating film 135. The surface 101 of the first wafer 100 is formed by the surface 133 of the first surface film 132 in the first device layer 130. Furthermore, the first device layer 130 comprises, in order from the surface, the first surface film 132, the first device 131, and the insulating film 135. In other words, the first wafer 100 is composed of, in order from the surface 101, the first surface film 132, the first device 131, the insulating film 135, and the first substrate 110.

[0016] Each of the multiple first devices 131 includes, for example, elements for constituting an IC, semiconductor memory, or image sensor. The multiple first devices 131 are formed in multiple regions demarcated by multiple streets 134 formed in a grid pattern.

[0017] The first surface film 132 may be one of the following: silicon oxide film (SiO2 film), silicon carbide film (SiC film), silicon nitride film (SiN film), silicon carbonitride film (SiCN film), SiOC film, SiON film, or TEOS film.

[0018] The insulating film 135 is laminated between the first substrate 110 and the first device 131, and in areas where the first device 131 is not present, it is laminated between the first substrate 110 and the first surface film 132, and is deposited on the surface 111 side of the first substrate 110 to form the first device 131. Therefore, the first device 131 is formed on the surface of the insulating film 135 (bottom surface in Figure 1). The insulating film 135 can be exemplified by being one of the following: silicon oxide film (SiO2 film), silicon carbide film (SiC film), silicon nitride film (SiN film), silicon carbonitride film (SiCN film), SiOC film, SiON film, or TEOS film. The insulating film 135 absorbs the laser beam LB1 irradiated during the deformation process. Note that the insulating film 135 does not need to be newly deposited, as long as it is a film that absorbs the laser beam LB1. In other words, if the film formed when creating the first device layer 130 is a silicon oxide film (SiO2 film), silicon nitride film (SiN film), or silicon carbonitride film (SiCN film), then the laser beam LB1 can be absorbed by that film in the same way as the insulating film 135.

[0019] The second wafer 200 comprises a second substrate 210 made of silicon, similar to the first substrate 110 described above, and a second device layer 230 formed on a surface 211 of the second substrate 210, which is one side in the thickness direction. The back surface 202 of the second wafer 200 is formed by the back surface 212 of the second substrate 210.

[0020] The second device layer 230 is formed in the same manner as the first device layer 130 and comprises a plurality of second devices 231 and a second surface film 232 formed on the surfaces of the plurality of second devices 231 as a bonding film. The surface 201 of the second wafer 200 is formed by the surface 233 of the second surface film 232 in the second device layer 230. Therefore, the second wafer 200 has second devices 231 on its surface 201. In addition, in the second wafer 200, similar to the first wafer 100, an insulating film (not shown) is formed on the surface 211 of the second substrate 210, and the second devices 231 are formed on the surface of the insulating film.

[0021] Each of the multiple second devices 231 also contains elements similar to those in the first device 131, and is arranged to correspond to the first device 131 by being formed in multiple regions demarcated by multiple streets 234 formed in a grid. The second surface film 232 is made of a material that can be bonded to the first surface film 132.

[0022] Before bonding the wafers 100 and 200, for example, the surface 133 of the first surface film 132 of the first wafer 100 and the surface 233 of the second surface film 232 of the second wafer 200 are irradiated with a plasma of a rare gas generated using a rare gas and high-frequency power. This activates the surfaces 133 and 233 of the first and second surface films 132 and 232, respectively, and then the wafers 100 and 200 are bonded by plasma activation bonding of the surfaces 133 and 233. This bonding forms a bonded wafer 300, and the first device 131 and the second device 231 are bonded on the bonded wafer 300. The second wafer 200 may have a configuration in which only the second surface film 232 is provided on the surface 211 of the second substrate 210.

[0023] [Transformation process] A deformation process is performed on the bonded wafer 300 as shown in Figures 1A to 1C. The deformation process is carried out using a chuck table 11 and a laser irradiation unit 12, which constitute the processing apparatus 1. In the deformation process, the second wafer 200 side of the bonded wafer 300 is transported to and held on the chuck table 11 via a transport mechanism (not shown). Then, as shown in Figure 1A, a laser beam LB1 with a penetrating wavelength is pulsed from the laser irradiation unit 12 toward the bonded wafer 300, from the back surface 102 of the first wafer 100 toward the first substrate 110. In other words, the laser beam LB1 irradiated from the laser irradiation unit 12 is irradiated from the first substrate 110 side (back surface 102 side) of the first wafer 100.

[0024] The laser beam LB1 used in the deformation process is set to a wavelength λ within the range of 1000 nm to 3000 nm, or 8000 nm to 11000 nm. By setting the wavelength λ to this range, the energy of the laser beam LB1 can be efficiently absorbed by the insulating film 135 at the focal point while allowing the laser beam LB1 to pass through the first substrate 110 of the first wafer 100.

[0025] The laser beam LB1 emitted from the laser irradiation unit 12 is adjusted by the focusing lens of the laser irradiation unit 12 to focus onto the insulating film 135 in the first wafer 100. After this adjustment, the laser beam LB1 is irradiated onto the insulating film 135 in a spiral trajectory centered on the center of the first wafer 100, for example. At this time, as shown in Figure 1B, the chuck table 11 holding the bonded wafer 300 is rotated around an axis extending in the vertical direction, while the chuck table 11 and the laser irradiation unit 12 are moved relative to each other in the horizontal direction.

[0026] This relative movement causes the irradiation position of the laser beam LB1 onto the insulating film 135 to shift from the outer periphery, which is one direction in the planar direction of the first wafer 100, toward the center, which is the other direction. After irradiating the first wafer 100 with the laser beam LB1 in a range extending from the outer periphery to the midpoint of the radial position (shown as a halftone dot in Figure 1B), the irradiation of the laser beam LB1 is stopped. As a result, the laser beam LB1 is not irradiated in a circular region approximately half the radius from the center of the first wafer 100, while the laser beam LB1 is irradiated onto the insulating film 135 in the ring-shaped (annular) region outside of that.

[0027] In the region of the insulating film 135 irradiated with the laser beam LB1, heating increases lattice defects in the insulating film 135 while it remains a single crystal. Furthermore, increasing the output of the laser beam LB1 modifies it from a single crystal to a polycrystalline material. When it is modified to a polycrystalline material by such heating, the volume of the insulating film 135 expands due to thermal expansion, and this thermal expansion of the insulating film 135 deforms the first substrate 110 as shown in Figure 1C. As a result, in the ring-shaped region along the outer edge of the first substrate 110, the insulating film 135 peels off from the first device 131 and the first surface film 132 in the first device layer 130, and the first substrate 110 lifts up and warps together with the insulating film 135. In other words, the outer edge and the central side of the first substrate 110 deform in a direction that intersects the planar direction of the first substrate 110, i.e., in the vertical direction of Figure 1C, with different positions on the outer edge and the central side in the planar direction (horizontal direction). In other words, strain occurs at the interface between the first device 131 and the first surface film 132 and the insulating film 135 in the first device layer 130, making the first substrate 110 more prone to peeling.

[0028] Here, the laser irradiation unit 12 may be a laser unit that irradiates the first wafer 100 with a laser beam LB1 to heat the first substrate 110. It is a temperature difference forming unit that heats the first wafer 100 by irradiation with the laser beam LB1 to create a temperature difference between the first wafer 100 and the second wafer 200. The laser beam of the laser irradiation unit 12 that irradiates the first wafer 100 can be changed as described later. The laser irradiation unit 12 is also a deformation unit that deforms at least a part of the first substrate 110 in the first wafer 100 of the bonded wafer 300. The temperature difference forming unit that creates a temperature difference between the first wafer 100 and the second wafer 200 may be a cooling unit that cools the first wafer 100 or the second wafer 200, as described later.

[0029] [Peeling process] After the deformation process, a peeling process is performed to separate the first substrate 110 of the first wafer 100 from the second wafer 200, as shown in Figures 2A and 2B. The peeling process is performed using a peeling device 20 (peeling unit) that constitutes the processing apparatus 1. In the peeling process, the bonded wafer 300 is transported and held on the chuck table 21 of the peeling device 20 via a transport mechanism (not shown) (see Figure 2A). Next, the back surface 102 of the first wafer 100 on the bonded wafer 300 is held by a suction pad 23 connected to a suction source 22, which generates negative pressure at its lower end. In this embodiment, the parts of the back surface 102 of the first wafer 100 that are held by the suction pad 23 are multiple locations near the outer periphery of the back surface 102.

[0030] Subsequently, as shown in Figure 2B, the suction pad 23 is raised via the lifting mechanism 24, applying a force that separates the first wafer 100 from the second wafer 200. As a result, the lower surface (front surface) of the insulating film 135 is separated from the upper surface (back surface) of the first device layer 130 and the first surface film 132, and the insulating film 135 of the device layer 130 is peeled off from the bonded wafer 300. In this way, the first wafer 100, on which the insulating film 135 is formed by heat treatment such as a thermal oxide film or thermal nitride film on the first substrate 110, has a strong bond between the first substrate 110 and the insulating film 135, so the insulating film 135 is peeled off together with the first substrate 110. After this peeling, the first device 131 remains bonded to the second wafer 200. Therefore, by performing the peeling process, the first device 131 is transferred (remains) on the second wafer 200, and a bonded wafer 300 is formed with the transfer completed.

[0031] According to the first embodiment described above, the first substrate 110 can be peeled off together with the insulating film 135 at the interface between the first device 131 and the first surface film 132 in the first device layer 130 and the insulating film 135. Furthermore, in the case of the insulating film 135 deposited using plasma CVD, since the bonding force between the insulating film 135 and the first substrate 110 is not strong, only the first substrate 110 can be peeled off at the interface between the insulating film 135 and the first substrate 110. As a result, polishing is not required to flatten the upper surface of the bonded wafer 300 exposed in Figure 1C after the peeling off of the first substrate 110, thereby improving productivity.

[0032] Next, embodiments of the present invention other than those described above will be described. In the following description, the same reference numerals may be used for components that are the same as or equivalent to those described in embodiments described before the embodiment being described, and the description may be omitted or simplified.

[0033] [Second Embodiment] Next, a second embodiment of the present invention will be described with reference to Figure 3. Figures 3A to 3C are explanatory diagrams of the deformation process of the bonding wafer processing method according to the second embodiment. In the second embodiment, the deformation process is modified compared to the first embodiment.

[0034] [Transformation process] In the deformation step of the second embodiment, as shown in Figure 3A, a laser beam LB2 with a wavelength that penetrates the insulating film 135 is pulsed and irradiated from the back surface 102 of the first wafer 100 from the laser irradiation unit 12. The wavelength λ of this laser beam LB2 is within the range of 1000 nm to 3000 nm, or 8000 nm to 11000 nm, and is lower in power than the laser beam LB1 irradiated in the deformation step of the first embodiment. The laser beam LB2 in the second embodiment may have the same wavelength as the laser beam LB1 in the first embodiment.

[0035] In the second embodiment, the laser beam LB2 is irradiated onto the insulating film 135 in the same manner as the laser beam LB1 in the first embodiment, following a spiral trajectory centered on the center of the first wafer 100. The laser beam LB2 is irradiated onto the insulating film 135 in a range extending from the outer circumference of the first wafer 100 to the midpoint of the radial position, and as shown in Figure 3A, a lattice defect layer 136 is formed in a ring shape within the insulating film 135. When viewed from above, the lattice defect layer 136 is formed in an annular region along the outer circumference of the first wafer 100 (insulating film 135).

[0036] The modification step of the second embodiment further involves pulsed irradiation of the lattice defect layer 136 with a laser beam LB3 having a wavelength that is transparent to the insulating film 135 from the laser irradiation unit 12. In this laser beam LB3 as well, the wavelength λ is within the range of 1000 nm to 3000 nm, or 8000 nm to 11000 nm, and the output is lower than that of the laser beam LB2 described above. This laser beam LB3 may have the same wavelength as the laser beam LB2, or it may have the same wavelength as the laser beam LB1 of the first embodiment. When irradiating with the laser beam LB3, similar to when irradiating with the laser beam LB2, the laser beam is irradiated to a ring-shaped (annular) region along the outer circumference of the insulating film 135, that is, to the region where the lattice defect layer 136 is formed.

[0037] As a result, the lattice defect layer 136 is heated, and this heating causes the first substrate 110 to deform as shown in Figure 3C. This deformation is the same as in the first embodiment, where the insulating film 135 peels off from the first device 131 and the first surface film 132 at the first device layer 130, and the first substrate 110 lifts up and warps together with the insulating film 135.

[0038] In the second embodiment, as in the first embodiment, the first substrate 110 can be deformed, and the first substrate 110 can be peeled off by performing the peeling process, using the lattice defect layer 136 formed on the insulating film 135 as a starting point for separation.

[0039] [Third Embodiment] Next, a third embodiment of the present invention will be described with reference to Figure 4. Figures 4A and 4B are explanatory diagrams of the deformation process of the bonding wafer processing method according to the third embodiment, and the third embodiment modifies the deformation process compared to the first embodiment.

[0040] [Transformation process] In the deformation step of the third embodiment, as shown in Figure 4A, a laser beam LB4 with an absorbing wavelength, for example, λ of 455 nm, is irradiated from the laser irradiation unit 12 onto the back surface 112 of the first substrate 110 on the first wafer 100. In the irradiation of the laser beam LB4 in the third embodiment, similar to the laser beam LB1 in the first embodiment, the irradiation is performed in a spiral trajectory centered on the center of the first wafer 100. As a result, as shown by the dashed diagonal pattern in Figure 4A, the laser beam LB4 is irradiated onto the first substrate 110 in a range extending from the outer circumference of the first wafer 100 to the midpoint of the radial position, and the first substrate 110 is heated in a ring shape. When viewed from above, this range is an annular region along the outer circumference of the first wafer 100.

[0041] As a result of this heating, the first substrate 110 undergoes thermal deformation as shown in Figure 4B. This thermal deformation is the same as in the first embodiment, where the insulating film 135 peels off from the first device 131 and the first surface film 132 at the first device layer 130, and the first substrate 110 lifts up and warps together with the insulating film 135.

[0042] In the third embodiment, the first substrate 110 can be deformed in the same way as in the first embodiment. This allows the first substrate 110 to be peeled off together with the insulating film 135 at the interface between the first device 131 and the insulating film 135 or between the first surface film 132 and the insulating film 135 in the first device layer 130, or to be peeled off only the first substrate 110 at the interface between the insulating film 135 and the first substrate 110. In addition to the above, heating of the first wafer 100 may be performed, for example, by a heater unit that blows hot air or warm air onto the first wafer 100.

[0043] [Fourth Embodiment] Next, a fourth embodiment of the present invention will be described with reference to Figure 5. Figures 5A and 5B are explanatory diagrams of the deformation process of the bonding wafer processing method according to the fourth embodiment. In the fourth embodiment, the deformation process is modified compared to the first embodiment.

[0044] In the deformation process of the fourth embodiment, as shown in Figure 5A, a chuck table 11 on which a Peltier element 14 is arranged is used, and the second substrate 210 (second wafer 200) of the bonded wafer 300 held on the chuck table 11 is cooled by the Peltier element 14. Due to this cooling, the first substrate 110 undergoes thermal deformation as shown in Figure 5B. This thermal deformation is the same as in the first embodiment, and the insulating film 135 peels off from the first device 131 and the first surface film 132 at the first device layer 130, causing the first substrate 110 to lift up and warp together with the insulating film 135.

[0045] Here, the Peltier element 14 is a cooling unit that cools the second wafer 200, and is a temperature difference forming unit that cools the second wafer 200 to create a temperature difference between the first wafer 100 and the second wafer 200. The Peltier element 14 is also a deformation unit that deforms at least a portion of the first substrate 110 in the first wafer 100 of the bonded wafer 300.

[0046] In the fourth embodiment, as in the first embodiment, the first substrate 110 can be deformed, and the first substrate 110 can be peeled off at the interface between the first device 131 and the first surface film 132 and the insulating film 135 in the first device layer 130 by performing a peeling process. The bonded wafer 300 may be heated before being cooled with the cooling unit.

[0047] In addition to the above, the second substrate 210 may be cooled by circulating a coolant through the chuck table 11 to cool the chuck table 11, or by edge clamping the bonded wafer 300 and blowing cold air onto the second substrate 210. Furthermore, the second substrate 210 may be cooled by bringing a cooled component other than the chuck table 11 into contact with the second substrate 210, or by irradiating the second substrate 210 with a laser. It may also be cooled by spraying cold air (liquid nitrogen) from a nozzle.

[0048] [Fifth Embodiment] Next, a fifth embodiment of the present invention will be described with reference to Figure 6. Figures 6A and 6B are explanatory diagrams of the deformation process of the bonding wafer processing method according to the fifth embodiment. In the fifth embodiment, the deformation process is modified compared to the first embodiment.

[0049] In the deformation step of the fifth embodiment, as shown in Figure 6, a transport mechanism 26 equipped with a transport pad 28 on which a Peltier element 27 is disposed is used, and the first substrate 110 (first wafer 100) of the bonded wafer 300 held on the transport pad 28 is cooled by the Peltier element 27. Due to this cooling, the first substrate 110 undergoes thermal deformation as shown in Figure 6B. This thermal deformation is the same as in the first embodiment, and the insulating film 135 peels off from the first device 131 and the first surface film 132 at the first device layer 130, and the first substrate 110 lifts up and becomes warped together with the insulating film 135.

[0050] Here, the Peltier element 27 is a cooling unit that cools the first wafer 100, and is a temperature difference forming unit that cools the first wafer 100 to create a temperature difference between the first wafer 100 and the second wafer 200. The Peltier element 27 is also a deformation unit that deforms at least a portion of the first substrate 110 in the first wafer 100 of the bonded wafer 300.

[0051] In the fifth embodiment, as in the first embodiment, the first substrate 110 can be deformed, and the first substrate 110 can be peeled off at the interface between the first device 131 and the first surface film 132 and the insulating film 135 in the first device layer 130 by performing the peeling process. The bonded wafer 300 may be heated before being cooled with the cooling unit.

[0052] In addition to the above, the first substrate 110 may be cooled by spraying cold air (liquid nitrogen) from a nozzle, or by laser cooling.

[0053] [Sixth Embodiment] Next, a sixth embodiment of the present invention will be described with reference to Figure 7. Figures 7A to 7C are explanatory diagrams of the deformation process of the bonding wafer processing method according to the sixth embodiment. In the sixth embodiment, the focusing position of the laser beam LB1 in the deformation process is changed compared to the first embodiment. The laser beam LB1 irradiated in this deformation process has a wavelength that transmits to the first substrate 110, similar to the first embodiment.

[0054] As shown in Figure 7A, in the deformation step of the sixth embodiment, the irradiated laser beam LB1 is adjusted by the focusing lens of the laser irradiation unit 12 so that it is focused into the interior of the first substrate 110 on the first wafer 100. More specifically, the focusing position of the laser beam LB1 on the bonded wafer 300 is set to a position near the surface 111 of the first substrate 110, while being displaced from the surface 111 toward the back surface 112.

[0055] After adjusting the focusing position of the laser beam LB1, for example, when viewed from the vertical direction in Figure 7A (the thickness direction of the first wafer 100), the laser beam LB1 is irradiated onto the first substrate 110 in such a way that it forms a spiral trajectory centered on the center of the first wafer 100. At this time, as shown in Figure 7B, the chuck table 11 that holds the bonded wafer 300 is rotated around an axis extending in the vertical direction, while the chuck table 11 and the laser irradiation unit 12 are moved relative to each other in the horizontal direction.

[0056] This relative movement causes the irradiation position of the laser beam LB1 onto the first substrate 110 to be displaced in a spiral trajectory from the outer circumference to the center of the first substrate 110, and numerous processing marks 114 are formed at predetermined intervals along this trajectory. The processing marks 114 are formed in such a way that the interior of the first substrate 110 is modified from a single crystal to a polycrystalline structure. After irradiating the first substrate 110 from the outer circumference to the midpoint of the radial position with the laser beam LB1, the irradiation of the laser beam LB1 is stopped.

[0057] As a result, a modified layer 115 is formed within the first substrate 110 by numerous processing marks 114 in an annular region along the outer periphery (one side in the surface direction) of the first substrate 110. Due to the formation of the modified layer 115, the volume of the portion of the first substrate 110 close to the bonding surface with the first device layer 130 expands, as shown by the dashed line in Figure 7B. Due to this expansion, as shown in Figure 7C, the insulating film 135 peels off from the first device 131 and the first surface film 132 in the ring-shaped (annular) region along the outer edge of the first substrate 110, similar to the first embodiment, and the first substrate 110 lifts up and deforms into a warped state together with the insulating film 135.

[0058] In the sixth embodiment, as in the first embodiment, the first substrate 110 can be deformed, and the first substrate 110 can be peeled off at the interface between the first device 131 and the first surface film 132 and the insulating film 135 in the first device layer 130 by performing a peeling process.

[0059] As shown in Figures 7A to 7C, the spacing of the processing marks 114 in the modified layer 115 is set to gradually widen from the outer edge towards the center in the radial direction of the first substrate 110. By setting the spacing in this manner, the warp of the first substrate 110 can be stably formed. However, this does not prevent setting the spacing of the processing marks 114 to be the same throughout the radial direction of the first substrate 110.

[0060] [Seventh Embodiment] Next, a seventh embodiment of the present invention will be described with reference to Figure 8. Figure 8 is an explanatory diagram of the deformation process of the bonding wafer processing method according to the seventh embodiment, where Figure 8A shows the surface heating process and Figures 8B and 8C show the cooling process, respectively. In the seventh embodiment, the deformation process is modified compared to the first embodiment. In the deformation process of the seventh embodiment, laser forming is performed by sequentially carrying out the surface heating process and the cooling process.

[0061] [Surface heating process] In the surface heating process, the back surface 202 of the second wafer 200 of the bonded wafer 300 is held facing downwards on the chuck table 11 of the processing apparatus 1, and then the laser irradiation unit 12 is brought facing the back surface 102 of the first wafer 100. Then, the laser irradiation unit 12 and the chuck table 11 are moved relative to each other to position the laser irradiation unit 12 above the midpoint of the radial position on the first wafer 100. After that, a laser beam LB5 with an absorbing wavelength (for example, 455 nm) is pulsed onto the first substrate 110 of the first wafer 100.

[0062] In the surface heating process, the laser beam LB5 emitted from the laser irradiation unit 12 is adjusted by the focusing lens of the laser irradiation unit 12 to focus onto the back surface 112 of the first substrate 110. After this adjustment, the laser beam LB5 is emitted from the laser irradiation unit 12 while the chuck table 11 holding the bonded wafer 300 is rotated around an axis extending in the vertical direction. As a result, the laser beam LB5 is emitted onto the back surface 112 of the first substrate 110 in a circular trajectory centered on the center of the back surface 112 of the first substrate 110, and the first substrate 110 is heated at the irradiated position.

[0063] [Cooling process] After the surface heating process, a cooling process is performed to cool the heated portion 117, as shown in Figure 8B. In the cooling process, the chuck table 11 on which the bonded wafer 300 is held and the cooling fluid supply unit 13 are moved relative to each other, so that the cooling fluid supply unit 13 is positioned above the heated portion 117 of the first substrate 110. Then, while the chuck table 11 is rotated around an axis extending in the vertical direction, air is blown from the cooling fluid supply unit 13 as a cooling fluid. As a result, the heated portion 117 on the back surface 112 of the first substrate 110 is cooled, and the heated portion 117 shrinks locally. Due to this shrinkage, as shown in Figure 8C, the insulating film 135 peels off from the first device 131 and the first surface film 132 in the first device layer 130 on the outer periphery of the heated portion 117, and the first substrate 110 lifts up and deforms into a warped state together with the insulating film 135.

[0064] In the seventh embodiment, the first substrate 110 can be bent by laser forming through a surface heating step and a cooling step, thereby causing localized thermoplastic deformation. As a result, the first substrate 110 can be deformed in the seventh embodiment as in the first embodiment, and the first substrate 110 can be peeled off at the interface between the first device 131 and the first surface film 132 and the insulating film 135 in the first device layer 130 by performing a peeling step. In the cooling step, if the portion of the first substrate 110 heated in the surface heating step can be cooled, air may be blown over the entire back surface 112 of the first substrate 110 to cool it. Alternatively, the air blowing may be omitted, and only the rotation of the chuck table 11 may be performed.

[0065] [Eighth Embodiment] Next, an eighth embodiment of the present invention will be described with reference to Figure 9. Figures 9A and 9B are explanatory diagrams of the deformation process of the bonding wafer processing method according to the eighth embodiment. In the eighth embodiment, the configuration of the first wafer 100 is changed compared to the first embodiment. In addition, in the eighth embodiment, the irradiation position of the laser beam LB1 and the peeling position of the first substrate 110 in the deformation process are changed compared to the first embodiment.

[0066] In the eighth embodiment, the first wafer 100, as shown in Figure 9A, includes a metal film 142 between the surface 111 of the first substrate 110 and the insulating film 135 of the first device layer 130. The metal film 142 can be made of materials such as polysilicon, titanium, nickel, Si-Ge, or SiN, and can be formed by vapor deposition or sputtering. The bonding force between the metal film 142 and the insulating film 135 is weaker than the bonding force between the metal film 142 and the first substrate 110.

[0067] In the deformation step of the eighth embodiment, a laser beam LB1 with the same wavelength λ and output as in the first embodiment is irradiated onto the metal film 142 from the laser irradiation unit 12, heating the metal film 142. The irradiation of the laser beam LB1 is performed on the metal film 142 in a spiral trajectory centered on the center of the first wafer 100. Furthermore, the irradiation of the laser beam LB1 is performed on the metal film 142 in a range extending from the outer circumference of the first wafer 100 to the midpoint of the radial position, so that the laser beam LB1 is irradiated onto a ring-shaped (annular) region along the outer circumference of the metal film 142. Due to the heating of the metal film 142, as shown in Figure 9B, the metal film 142 and the insulating film 135, which have weaker bonding forces, peel off, and the first substrate 110 lifts up and becomes warped together with the metal film 142.

[0068] In the eighth embodiment, as in the first embodiment, the first substrate 110 can be deformed, and the first substrate 110 can be peeled off at the interface between the insulating film 135 and the metal film 142 by performing the peeling process. In this case, unlike the first embodiment, the first substrate 110 separates from the insulating film 135, and the insulating film 135 remains bonded to the first device 131 and the first surface film 132 at the first device layer 130 without peeling off.

[0069] [Ninth Embodiment] Next, a ninth embodiment of the present invention will be described with reference to Figure 10. Figure 10 is an explanatory diagram of each step of the bonding wafer processing method according to the ninth embodiment, where Figure 10A shows the lattice defect layer formation step, and Figures 10B and 10C show the deformation step, respectively. The main change in the ninth embodiment compared to the first embodiment is the implementation of the lattice defect layer formation step before the deformation step.

[0070] [Lattice Defect Layer Formation Process] In the lattice defect layer formation process, a lattice defect layer 137 is formed within the insulating film 135 of the first device layer 130, having a similar configuration to the lattice defect layer 136 of the second embodiment, but with a different formation range.

[0071] In the lattice defect layer formation process, a laser beam LB2 with the same wavelength λ and power output as in the second embodiment is irradiated onto the insulating film 135 from the laser irradiation unit 12. The irradiation of the insulating film 135 with the laser beam LB2 follows a spiral trajectory centered on the center of the first wafer 100. Furthermore, the irradiation of the laser beam LB2 is performed over almost the entire area of ​​the insulating film 135, from the outer periphery to the center of the first wafer 100. As a result, as shown in Figure 10A, a planar lattice defect layer 137 is formed within the insulating film 135. In other words, almost the entire upper surface (back surface) of the insulating film 135 in Figure 10A is made up of the lattice defect layer 137.

[0072] [Transformation process] In the deformation step of the ninth embodiment, as shown in Figure 10B, a laser beam LB3 with the same wavelength λ and output as in the second embodiment is irradiated onto the insulating film 135 from the laser irradiation unit 12. Even when irradiating with the laser beam LB3, the insulating film 135 is irradiated in a spiral trajectory centered on the center of the first wafer 100. Furthermore, the irradiation of the insulating film 135 with the laser beam LB3 is performed in a range extending from the outer circumference of the first wafer 100 to the midpoint of the radial position, and the laser beam LB3 is irradiated onto a ring-shaped (annular) region along the outer circumference of the insulating film 135. As a result, the insulating film 135 is heated, and this heating causes the first substrate 110 to deform as shown in Figure 10C. Due to this deformation, the first substrate 110 peels off from the lattice defect layer 137 of the insulating film 135, and the first substrate 110 lifts up and becomes warped.

[0073] In the ninth embodiment, as in the first embodiment, the first substrate 110 can be deformed, and by performing the peeling process, only the first substrate 110 can be peeled off at the interface between the lattice defect layer 137 of the insulating film 135 and the first substrate 110. At this time, the first substrate 110 separates from the insulating film 135, and the insulating film 135 remains bonded to the first device 131 and the first surface film 132 at the first device layer 130 without peeling off.

[0074] [Tenth Embodiment] Next, a tenth embodiment of the present invention will be described with reference to Figure 11. Figure 11 is an explanatory diagram of the deformation process of the bonding wafer processing method according to the tenth embodiment. In the tenth embodiment, the deformation process is modified compared to the ninth embodiment.

[0075] [Transformation process] In the modification step of the tenth embodiment, as shown in Figure 11, a laser beam LB4 with the same wavelength λ and output as in the third embodiment is irradiated from the laser irradiation unit 12 onto the back surface 112 of the first substrate 110 on the first wafer 100. Even when irradiating with the laser beam LB4, similar to the laser beam LB4 in the third embodiment, the irradiation is performed in a spiral trajectory centered on the center of the first wafer 100. As a result, as shown by the dashed diagonal pattern in Figure 11, the laser beam LB4 irradiates the first substrate 110 in a ring-shaped area extending from the outer periphery to the midpoint of the radial position of the first wafer 100, and the first substrate 110 is heated.

[0076] This heating deforms the first substrate 110 in the same way as in the ninth embodiment, causing the first substrate 110 to peel off from the lattice defect layer 137 of the insulating film 135, and the first substrate 110 to lift up and become warped (see Figure 10C). As a result, in the tenth embodiment as well, the first substrate 110 can be peeled off at the interface between the lattice defect layer 137 of the insulating film 135 and the first substrate 110 by performing the peeling process.

[0077] Furthermore, if a planar lattice defect layer 137 is formed within the insulating film 135, the modification process is not limited to the 9th and 10th embodiments. A modified layer 115 may be formed within the first substrate 110, similar to the 6th embodiment, or laser forming may be performed, similar to the 7th embodiment.

[0078] [Embodiment 11] Next, an eleventh embodiment of the present invention will be described with reference to Figure 12. Figures 12A to 12C are explanatory diagrams of the deformation process of the bonding wafer processing method according to the eleventh embodiment. In the eleventh embodiment, the configuration of the first wafer 100 is changed compared to the first embodiment. In addition, in the eleventh embodiment, the irradiation position of the laser beam LB1 in the deformation process and the peeling position of the first substrate 110 are changed compared to the first embodiment.

[0079] In the eleventh embodiment, the first device layer 130 of the first wafer 100 includes a peel-accelerating film 138 laminated between the first substrate 110 and the insulating film 135, as shown in Figure 12A. Therefore, the first device layer 130 comprises, in order from the surface, the first device 131, the insulating film 135, and the peel-accelerating film 138. The peel-accelerating film 138 can be formed from the same material as the insulating film 135, and the bonding force between the peel-accelerating film 138 and the insulating film 135 is weaker than the bonding force between the peel-accelerating film 138 and the first substrate 110.

[0080] In the deformation step of the 11th embodiment, as shown in Figure 12B, a laser beam LB1 with the same wavelength λ and output as in the first embodiment is irradiated onto the peel-promoting film 138 from the laser irradiation unit 12, heating the peel-promoting film 138. The irradiation of the peel-promoting film 138 with the laser beam LB1 follows a spiral trajectory centered on the center of the first wafer 100. Furthermore, the irradiation of the peel-promoting film 138 with the laser beam LB1 is performed in a range extending from the outer circumference of the first wafer 100 to the midpoint of the radial position, so that the laser beam LB1 is irradiated onto a ring-shaped (annular) region along the outer circumference of the peel-promoting film 138. Due to the heating of the peel-promoting film 138, as shown in Figure 12C, the peel-promoting film 138 and the insulating film 135, which have weaker bonding forces, peel off, and the first substrate 110 lifts up and becomes warped together with the peel-promoting film 138.

[0081] In the eleventh embodiment, the first substrate 110 can be deformed in the same way as in the first embodiment, and the first substrate 110 can be peeled off together with the peeling accelerator film 138 at the interface between the insulating film 135 and the peeling accelerator film 138 by performing the peeling process. In this case, unlike the first embodiment, the peeling accelerator film 138 separates from the insulating film 135, and the insulating film 135 remains bonded to the first device 131 and the first surface film 132 in the first device layer 130 without peeling off.

[0082] In addition, in the second to seventh embodiments, the first wafer 100 may be configured to include a peel-promoting film 138, similar to the eleventh embodiment, and the deformation process and peel-off process may be performed.

[0083] [The 12th Embodiment] Next, a twelfth embodiment of the present invention will be described with reference to Figure 13. Figure 13 is an explanatory diagram of each step of the bonding wafer processing method according to the twelfth embodiment, and Figures 13A to 13C show the deformation step, respectively. The main changes in the twelfth embodiment compared to the first embodiment are the configuration of the first wafer 100, the formation of the lattice defect layer 1381 in the deformation step, and the peeling position of the first substrate 110.

[0084] As shown in Figure 13A, the first wafer 100 in the twelfth embodiment has the same configuration as in the eleventh embodiment, and the first device layer 130 includes a peel-promoting film 138 laminated between the first substrate 110 and the insulating film 135. Therefore, the first device layer 130 comprises, in order from the surface, the first device 131, the insulating film 135, and the peel-promoting film 138.

[0085] [Transformation process] In the modification step of the twelfth embodiment, a lattice defect layer 1381 is formed within the peel-promoting film 138 of the first device layer 130. This lattice defect layer 1381 has the same configuration as the lattice defect layer 136 of the second embodiment, except that the layer formed is changed from an insulating film 135 to a peel-promoting film 138.

[0086] In the deformation step of the twelfth embodiment, a laser beam LB2 with the same wavelength λ and output as in the second embodiment is irradiated from the laser irradiation unit 12 onto the peel-accelerating film 138. The irradiation of the peel-accelerating film 138 with the laser beam LB2 follows a spiral trajectory centered on the center of the first wafer 100. The irradiation of the laser beam LB2 is performed in a range from the outer periphery to the center of the peel-accelerating film 138 and from the outer periphery to the midpoint of the radial position, and as shown in Figure 13A, a lattice defect layer 1381 is formed within the peel-accelerating film 138. When viewed from above, the lattice defect layer 1381 is formed in a ring-shaped (annular) region along the outer periphery of the first wafer 100 (peeling-accelerating film 138).

[0087] In the deformation step of the twelfth embodiment, as shown in Figure 13B, a laser beam LB3 with the same wavelength λ and output as in the second embodiment is irradiated onto the peel-accelerating film 138 from the laser irradiation unit 12. Even with the irradiation of the laser beam LB3, similar to the irradiation of the laser beam LB2, the laser beam is irradiated to a ring-shaped (annular) region along the outer circumference of the peel-accelerating film 138, that is, the region where the lattice defect layer 1381 is formed. This heats the peel-accelerating film 138, and this heating causes the first substrate 110 to deform as shown in Figure 13C. This deformation causes the peel-accelerating film 138 and the insulating film 135 to peel off, and the first substrate 110 lifts up and becomes warped together with the peel-accelerating film 138.

[0088] In the twelfth embodiment, the first substrate 110 can be deformed in the same way as in the eleventh embodiment, and the first substrate 110 can be peeled off together with the peeling accelerator film 138 at the interface between the insulating film 135 and the peeling accelerator film 138 by performing the peeling process.

[0089] [13th Embodiment] Next, a thirteenth embodiment of the present invention will be described with reference to Figure 14. Figures 14A and 14B are explanatory diagrams of the deformation process of the bonding wafer processing method according to the thirteenth embodiment. In the thirteenth embodiment, the configuration of the first wafer 100 is changed compared to the first embodiment. In addition, in the thirteenth embodiment, the irradiation position of the laser beam LB1 and the peeling position of the first substrate 110 in the deformation process are changed compared to the first embodiment.

[0090] In the 13th embodiment, the first device layer 130 of the first wafer 100 includes a peel-promoting film 138 and a metal film 139 laminated between the first substrate 110 and the insulating film 135, as shown in Figure 14A. The first device layer 130 comprises, in order from the surface, a first device 131, an insulating film 135, a metal film 139, and a peel-promoting film 138, with the metal film 139 laminated between the insulating film 135 and the peel-promoting film 138. The metal film 139 can be formed from the same material as the metal film 142 in the 8th embodiment, and the bonding force between the metal film 139 and the peel-promoting film 138 is weaker than the bonding force between the metal film 139 and the insulating film 135.

[0091] In the deformation step of the 13th embodiment, a laser beam LB1 with the same wavelength λ and output as in the first embodiment is irradiated onto the metal film 139 from the laser irradiation unit 12, heating the metal film 139. The irradiation of the laser beam LB1 is performed on the metal film 139 in a spiral trajectory centered on the center of the first wafer 100. Furthermore, the irradiation of the laser beam LB1 is performed on the metal film 139 in a range extending from the outer circumference of the first wafer 100 to the midpoint of the radial position, so that the laser beam LB1 is irradiated onto a ring-shaped (annular) region along the outer circumference of the metal film 139. Due to the heating of the metal film 139, as shown in Figure 14B, the metal film 139 and the peel-promoting film 138, which have weaker bonding forces, peel off, and the first substrate 110 lifts up and becomes warped together with the peel-promoting film 138.

[0092] In the 13th embodiment, the first substrate 110 can be deformed in the same way as in the first embodiment, and the first substrate 110 can be peeled off together with the peeling accelerating film 138 at the interface between the metal film 139 and the peeling accelerating film 138 by performing the peeling process.

[0093] Furthermore, as in the eighth and thirteenth embodiments, by changing the formation positions of the metal films 142 and 139 on the first wafer 100, or by changing whether or not the peel-accelerating film 138 is formed, it becomes possible to select between processing the first device layer 130 after the peeling process in which the metal film 139 remains, and processing in which the metal film 142 is removed. In addition, in the eighth and thirteenth embodiments, at least the first substrate 110 is peeled off from the second wafer 200. In other words, the metal film 139 formed between the insulating film 135 and the peel-accelerating film 138 in the thirteenth embodiment may be formed between the first substrate 110 and the peel-accelerating film 138.

[0094] [Embodiment 14] Next, a 14th embodiment of the present invention will be described with reference to Figure 15. Figure 15 is an explanatory diagram of each step of the bonding wafer processing method according to the 14th embodiment, where Figure 15A shows the lattice defect layer formation step, and Figures 15B and 15C show the deformation step, respectively. The main changes in the 14th embodiment compared to the first embodiment are the configuration of the first wafer 100, the implementation of the lattice defect layer formation step before the deformation step, and the peeling position of the first substrate 110 in the deformation step.

[0095] As shown in Figure 15A, the first wafer 100 in the 14th embodiment has the same configuration as in the 11th embodiment, and the first device layer 130 includes a peel-promoting film 138 laminated between the first substrate 110 and the insulating film 135. Therefore, the first device layer 130 comprises, in order from the surface, the first device 131, the insulating film 135, and the peel-promoting film 138.

[0096] [Lattice Defect Layer Formation Process] In the lattice defect layer formation process, a lattice defect layer 1382 is formed within the peel-promoting film 138 of the first device layer 130. This lattice defect layer 1382 has the same configuration as the lattice defect layer 137 of the ninth embodiment, except that the layer to be formed is changed from an insulating film 135 to a peel-promoting film 138.

[0097] In the lattice defect layer formation process, a laser beam LB2 with the same wavelength λ and output as in the second and ninth embodiments is irradiated onto the peel-promoting film 138 from the laser irradiation unit 12. The irradiation of the peel-promoting film 138 with the laser beam LB2 follows a spiral trajectory centered on the center of the first wafer 100. Furthermore, the irradiation of the laser beam LB2 is performed over almost the entire area of ​​the peel-promoting film 138, from the outer periphery to the center of the first wafer 100. As a result, as shown in Figure 15A, a planar lattice defect layer 1382 is formed within the peel-promoting film 138, or in other words, almost the entire upper side (back side) of the peel-promoting film 138 in Figure 15A becomes the lattice defect layer 1382.

[0098] [Transformation process] In the deformation step of the 14th embodiment, as shown in Figure 15B, a laser beam LB3 with the same wavelength λ and output as in the second and ninth embodiments is irradiated onto the peel-accelerating film 138 from the laser irradiation unit 12. Even when irradiating with the laser beam LB3, the peel-accelerating film 138 is irradiated in a spiral trajectory centered on the center of the first wafer 100. Furthermore, the irradiation of the laser beam LB3 is performed on the peel-accelerating film 138 in a range extending from the outer circumference of the first wafer 100 to the midpoint of the radial position, and the laser beam LB3 is irradiated onto a ring-shaped (annular) region along the outer circumference of the peel-accelerating film 138. As a result, the peel-accelerating film 138 is heated, and this heating causes the first substrate 110 to deform as shown in Figure 15C. Due to this deformation, the first substrate 110 peels off from the lattice defect layer 1381 of the peel-accelerating film 138, and only the first substrate 110 lifts up and becomes warped.

[0099] In the 14th embodiment, the first substrate 110 can be deformed in the same way as in the 9th embodiment, and by performing the peeling process, only the first substrate 110 can be peeled off at the interface between the lattice defect layer 1382 of the peeling-promoting film 138 and the first substrate 110. In this case, unlike the 11th embodiment, the first substrate 110 separates from the peeling-promoting film 138, and the state in which the peeling-promoting film 138 is bonded to the first device layer 130 without peeling off is maintained.

[0100] Furthermore, the present invention is not limited to the embodiments described above, and can be implemented with various modifications. In the embodiments described above, the size, shape, etc., shown in the accompanying drawings are not limited thereto, and can be appropriately modified within the scope that allows the present invention to exert its effects. In addition, the present invention can be implemented with appropriate modifications as long as it does not deviate from the scope of its objectives.

[0101] In the 13th embodiment, the deformation step may be performed by carrying out any of the deformation steps in the first to third, sixth, seventh, eleventh, and twelfth embodiments, instead of heating the metal film 139 by irradiation with the laser beam LB1, thereby deforming the first substrate 110.

[0102] Furthermore, in the eighth embodiment, the deformation step may be replaced with one of the deformation steps of the first, third, sixth, and seventh embodiments to deform the first substrate 110, instead of heating the metal film 142 by irradiation with the laser beam LB1.

[0103] Furthermore, in each of the above embodiments, the second wafer 200 may be configured in which the formation of the second device layer 230 having a plurality of second devices 231 and a second surface film 232 is omitted. Moreover, an insulating film similar to the insulating film 135 of the first device layer 130 may be formed in the second device layer 230 of the second wafer 200.

[0104] Furthermore, while the modification steps of the first to fourth and sixth to ninth embodiments described the case in which the laser beams LB1 to LB4 are irradiated in a spiral trajectory, the invention is not limited to this. For example, various modifications are possible, such as creating a trajectory along multiple concentric circles centered on the center of the first substrate 110, a trajectory arranged in multiple parallel straight lines, a trajectory with multiple wavy lines arranged side by side, or a zigzag trajectory.

[0105] Furthermore, in the deformation process in each embodiment, the locations that are contrasted by deformation that is positioned differently in a direction intersecting the planar direction of the first substrate 110 (thickness direction) are not limited to the outer circumference, which is one side of the planar direction of the first substrate 110, and the center side, which is the other side. For example, one side of the planar direction of the first substrate 110 may be one end of the diameter of the first substrate 110, while the other side of the planar direction of the first substrate 110 may be the other end of the diameter of the first substrate 110. In this case, during the deformation process, the position of the other end in the thickness direction of the first substrate 110 remains unchanged, while the position of the one end lifts up, thereby deforming it in a different position in the thickness direction.

[0106] Furthermore, before performing the deformation process, a delamination trigger may be created at the boundary between the first substrate 110 and the second wafer 200. The delamination trigger can be created by processing the outer periphery of the first substrate 110. For example, the tip of a needle may be pierced into the outer edge of the first substrate 110 to form the delamination trigger.

[0107] Furthermore, in the peeling process described above, the first substrate 110 of the first wafer 100 may be peeled from the second wafer 200 using the peeling apparatus 30 (peeling unit) shown in Figures 16A and 16B. After the bonded wafer 300 is transported and held on the chuck table 31 of the peeling apparatus 30, the outer periphery of the first substrate 110, which has warped upward from the insulating film 135 in the deformation process, is held by the gripping chucks 32 from the thickness direction (see Figure 16A). Multiple gripping chucks 32 are provided in the direction of the outer periphery of the first wafer 100; in other words, multiple locations on the outer periphery of the first substrate 110 are held by multiple gripping chucks 32.

[0108] Subsequently, as shown in Figure 16B, the gripping chuck 32 is raised via the lifting mechanism 34, applying a force that separates the first wafer 100 from the second wafer 200. As a result, in the delamination apparatus 30 of Figure 16, the surface 111 of the first substrate 110 is separated from the insulating film 135 and peeled off at the bonded wafer 300.

[0109] In the peeling process, the first substrate 110 may be peeled from the second wafer 200 using a holding table equipped with a suction surface that holds the back surface 112 of the first substrate 110 by suction. In addition, ultrasonic vibrations may be transmitted to the first substrate 110 in the peeling process. In addition, ultrasonic water with ultrasonic vibrations transmitted to it, or high-pressure air, may be introduced into the surface to be peeled in the peeling process. [Industrial applicability]

[0110] As described above, the present invention has the effect of improving productivity by making it possible to set the peeling position of the first substrate to the interface between the insulating film and the first device layer, thereby eliminating the need for polishing to flatten the surface of the bonded wafer exposed after peeling. [Explanation of symbols]

[0111] 1: Processing equipment 11: Chuck Table 12: Laser irradiation section (laser unit, temperature difference formation unit, deformation unit) 14: Peltier element (cooling unit, temperature difference formation unit, deformation unit) 20: Peeling device (peeling unit) 27: Peltier element (cooling unit, temperature difference formation unit, deformation unit) 100: First wafer 101: Surface 102: Surface 110: First board 111 :Surface 115: Modified layer 130: First device layer 131: First device 135: Insulating film 136: Lattice defect layer 137: Lattice defect layer 138: Peel-off promoting film 1381: Lattice Defect Layer 1382: Lattice defect layer 139: Metal film 142: Metal film 200: Second wafer 201 :Surface 231: Second device 300: Bonded wafer LB1: Laser beam LB2: Laser beam LB3: Laser beam LB4: Laser beam LB5: Laser beam

Claims

1. A method for processing a bonded wafer, comprising: a first wafer having a first device and an insulating film formed in order from the surface on the surface side of a first substrate; a first device layer and a second wafer being bonded together; and a method for processing a bonded wafer, wherein at least the first substrate is peeled off from the bonded wafer and the first device is transferred to the second wafer. A deformation step of deforming the first substrate such that at least one side of the first substrate in the planar direction is in a different position in a direction intersecting the planar direction, A method for processing a bonded wafer, comprising: a deformation step followed by a peeling step of peeling off at least the first substrate while leaving the first device on the second wafer.

2. A method for processing a bonded wafer according to claim 1, comprising a delamination promoting film between the insulating film and the first substrate.

3. A method for processing a bonded wafer according to claim 1, wherein a metal film is provided between the insulating film and the first substrate.

4. The method for processing a bonded wafer according to claim 2, wherein a metal film is provided between the insulating film and the delamination promoting film.

5. The method for processing a bonded wafer according to claim 2, further comprising a metal film between the peel-promoting film and the first substrate.

6. A method for processing a bonded wafer according to claim 1, comprising a step of forming a lattice defect layer by irradiating the insulating film with a laser beam to form a planar lattice defect layer within the insulating film.

7. A method for processing a bonded wafer according to claim 2, comprising a step of forming a lattice defect layer by irradiating the peel-promoting film with a laser beam to form a planar lattice defect layer within the peel-promoting film.

8. The deformation step is to irradiate the insulating film with a laser beam to heat and deform the insulating film, as described in claim 1.

9. The method for processing a bonded wafer according to claim 2, wherein the deformation step involves irradiating the peel-promoting film with a laser beam to heat and deform the peel-promoting film.

10. The deformation step is to irradiate the insulating film with a laser beam of a penetrating wavelength to form a ring-shaped lattice defect layer within the insulating film, and further irradiate the lattice defect layer with the laser beam to heat and deform the lattice defect layer, as described in claim 1.

11. The method for processing a bonded wafer according to claim 2, wherein the deformation step involves irradiating the delamination-promoting film with a laser beam of a transparent wavelength to form a ring-shaped lattice defect layer within the delamination-promoting film, and further irradiating the lattice defect layer with the laser beam to heat and deform the lattice defect layer.

12. The deformation step is to irradiate the first substrate with a laser beam of an absorbing wavelength to heat and thermally deform the first substrate, the method for processing a bonded wafer according to any one of claims 1 to 5.

13. The deformation step involves irradiating the first substrate with a laser beam of a transparent wavelength to form a modified layer within the first substrate and deform the first substrate, as described in any one of claims 1 to 5.

14. The deformation step comprises a surface heating step of irradiating the first substrate with a laser beam of an absorbing wavelength to heat a portion of the surface of the first substrate, and a cooling step of cooling the portion heated in the surface heating step to deform the first substrate, as described in any one of claims 1 to 5.

15. The deformation step is to partially cool the back surface of the first substrate to cause thermal deformation, the method for processing a bonded wafer according to any one of claims 1 to 5.

16. The deformation step is to irradiate the metal film with a laser beam to heat and deform it, a method for processing a bonded wafer according to any one of claims 3 to 5.

17. A processing apparatus for peeling off the first substrate from a bonded wafer, in which a first device layer comprising a first device and an insulating film is formed in order from the surface on the surface side of the first substrate, and a second wafer is bonded together, and transferring the first device to the second wafer, A processing apparatus comprising: a chuck table for holding the second wafer of the bonded wafer; a deformation unit for deforming at least a portion of the first substrate of the first wafer of the bonded wafer; and a peeling unit for peeling off the deformed first substrate.

18. The processing apparatus according to claim 17, wherein the deformation unit is a temperature difference forming unit that creates a temperature difference between the first wafer and the second wafer by performing at least one of heating and / or cooling on one of the first wafer and the second wafer.

19. The processing apparatus according to claim 18, wherein the temperature difference forming unit is a laser unit that heats the first substrate by irradiating the first wafer with a laser beam.

20. The processing apparatus according to claim 18, wherein the temperature difference forming unit is a heater unit for heating the first wafer.

21. The processing apparatus according to claim 18, wherein the temperature difference forming unit is a cooling unit for cooling the first wafer.

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