Laser processing apparatus, laser lift-off method, and method for manufacturing semiconductor device

Abstract

A laser processing apparatus according to one embodiment includes: a stage that holds a plurality of substrates on a concentric circle and rotates about a center of the concentric circle; and a laser irradiation device which is provided with a control unit that controls the output of the infrared pulse laser light such that a plurality of adjacent laser spots are spaced apart, and which is movable in the radial direction of the concentric circle. When the diameter of the plurality of laser spots is x and the interval between the plurality of adjacent laser spots in the rotation direction of the stage is L1, the control unit may satisfy xlt; l1 is used for controlling.

Description

[0001] Related applications

[0002] This application is based on and claims the priority interest of Japanese Patent Application No. 2021-152673, filed on September 17, 2021, the entire contents of which are incorporated herein by reference. Technical Field

[0003] Embodiments of this disclosure relate to a laser processing apparatus, a laser lift-off method, and a method for manufacturing a semiconductor device. Background Technology

[0004] NAND flash memory is known as a semiconductor memory device. This NAND flash memory has a memory cell array and its control circuitry. A known method for manufacturing a semiconductor memory device is to form the memory cell array chip and the control circuit chip separately on different substrates and then bond them together. In this case, the substrate on which the memory cell array chip is formed can be reused by laser lift-off. Summary of the Invention

[0005] The embodiments disclosed herein provide a laser processing apparatus, a laser lift-off method, and a method for manufacturing a semiconductor device that improves the manufacturing efficiency of semiconductor memory devices and the reusability efficiency of substrates.

[0006] The laser processing apparatus according to this embodiment includes: a stage that holds multiple substrates on a concentric circle and rotates about the center of the concentric circle; and a laser irradiation device that has a control unit and is movable in the radial direction of the concentric circle, the control unit controlling the output of an infrared pulsed laser in such a way that multiple adjacent laser spots are spaced apart.

[0007] Based on the above configuration, a laser processing apparatus, a laser lift-off method, and a semiconductor device manufacturing method can be provided that improve the manufacturing efficiency of semiconductor memory devices and the reuse efficiency of substrates. Attached Figure Description

[0008] Figure 1 This is a diagram showing the overall configuration of the semiconductor memory device (attached substrate) according to this embodiment.

[0009] Figure 2 This is a cross-sectional view showing the configuration of the semiconductor memory device (attached substrate) according to this embodiment.

[0010] Figure 3 This is a diagram showing the overall configuration of the semiconductor memory device according to this embodiment.

[0011] Figure 4This is a top view showing the basic configuration of the laser processing apparatus according to this embodiment.

[0012] Figure 5 This is a side view showing the basic configuration of the laser processing apparatus according to this embodiment.

[0013] Figure 6 This is an enlarged top view showing the laser irradiation area (laser spot) of the semiconductor memory device (adhesive substrate) 1 according to this embodiment.

[0014] Figure 7 This is a top view showing the basic configuration of the laser processing apparatus according to this embodiment.

[0015] Figure 8 This is a side view showing the basic configuration of the laser processing apparatus according to this embodiment.

[0016] Figure 9 This is an enlarged top view showing the laser irradiation area (laser spot) of the semiconductor memory device (adhesive substrate) 1 according to this embodiment. Detailed Implementation

[0017] Hereinafter, the laser processing apparatus and laser ablation method according to this embodiment will be described in detail with reference to the accompanying drawings. In the following description, elements having substantially the same function and structure are marked with the same symbols or symbols followed by letters, and will be described repeatedly only where necessary. The embodiments shown below illustrate apparatuses and methods for embodying the technical concept of this embodiment. The technical concept of the embodiments does not limit the materials, shapes, structures, and arrangements of the constituent parts to the following contents. The technical concept of the embodiments can also be obtained by making various modifications to the claims.

[0018] To make the description clearer, the accompanying drawings may sometimes schematically show the width, thickness, shape, etc. of various parts compared to the actual embodiment, but this is merely an example and does not limit the interpretation of the invention. In this specification and the accompanying drawings, elements having the same function as those described with respect to the already shown drawings are sometimes labeled with the same symbols, and repeated descriptions are omitted.

[0019] In each embodiment, the direction from each substrate toward the memory cell or control circuit is referred to as "upward." Conversely, the direction from the memory cell or control circuit toward each substrate is referred to as "downward." Thus, for ease of explanation, terms like "upward" or "downward" are used, but for example, the vertical relationship between the substrate and the memory cell could be configured to be the opposite of the illustration. Furthermore, in the following description, for example, the description of the memory cell on the substrate is merely to illustrate the vertical relationship between the substrate and the memory cell as described above; other components could also be arranged between the substrate and the memory cell.

[0020] Unless otherwise specified, the statements in this specification such as "α includes A, B, or C", "α includes any one of A, B, and C", and "α includes one selected from the group consisting of A, B, and C" do not exclude the possibility that α includes a combination of multiple A through C. Furthermore, these statements do not exclude the possibility that α includes other elements.

[0021] The following implementation methods can be combined with each other without causing technical contradictions.

[0022] <First Embodiment> [Semiconductor Memory Device (Laminated Substrate)]

[0023] use Figures 1 to 3 The structure of the semiconductor memory device (adhesive substrate) 1 according to this embodiment will be explained. Figure 1 This is a diagram showing the overall configuration of the semiconductor memory device (attached substrate) 1. Figure 2 This is a cross-sectional view showing the basic structure of a semiconductor memory device (attached substrate) 1. Figure 3 This is a diagram showing the overall configuration of the semiconductor memory device 2. (As shown) Figure 1 As shown, the semiconductor memory device (adhesive substrate) 1 includes a memory cell array chip 100 as a first circuit layer and a control circuit (CMOS circuit) chip 200 as a second circuit layer. The memory cell array chip 100 and the control circuit chip 200 are connected at a connection surface C1. Furthermore, the first and second circuit layers are not particularly limited. Therefore, the semiconductor memory device of this embodiment is sometimes referred to as a "semiconductor device".

[0024] [Structure of a memory cell array chip]

[0025] like Figure 2As shown, the memory cell array chip 100 has a substrate 10, a laser absorption layer 14, multiple electrode layers 16, multiple semiconductor pillars 15, and a memory-side wiring layer 17. Multiple electrode layers 16 are alternately stacked with multiple insulating layers on the substrate 10, separated by the laser absorption layer 14. Each semiconductor pillar 15 is arranged to penetrate the stacked electrode layers 16 in a direction perpendicular to the substrate 10. Each semiconductor pillar 15 is combined with the multiple electrode layers 16 separated by insulating layers, thereby functioning as multiple transistors containing memory cells. That is, in the memory cell array region 11 ( Figure 2 In the upper left portion, multiple transistors containing memory cells are arranged in three dimensions. Semiconductor pillar 15 is electrically connected to the source line at one end (on the substrate 10 side) and electrically connected to the memory-side wiring layer 17 at the other end (on the side opposite to the substrate 10). On the connection surface C1 of the memory-side wiring layer 17 on the side opposite to the substrate 10, connection terminals for connection to the control circuit chip 200 are arranged.

[0026] On the substrate 10, an outgoing region 12 is arranged parallel to the memory cell array region 11. Figure 2 (The upper right portion). In the lead-out region 12, multiple electrode layers 16 lead out terminal portions in a stepped manner. Moreover, each terminal portion is connected to vertical wiring via contact holes that open in the insulating film. These vertical wirings are electrically connected to the memory-side wiring layer 17 and connected to the control circuit chip 200 via connection terminals.

[0027] The substrate 10 can be a semiconductor wafer such as a silicon substrate or a glass substrate. A laser absorption layer 14 is disposed between the substrate 10 and the plurality of electrode layers 16. Figure 3 As shown, in this embodiment, the substrate 10 and laser absorption layer 14 of the semiconductor memory device (attached substrate) 1 are ultimately removed from the semiconductor memory device 2 during the semiconductor memory device manufacturing process by irradiating the laser absorption layer 14 with a laser. The laser absorption layer 14 is preferably, for example, a silicon oxide film. The semiconductor memory device 2 can also be monolithically fabricated into a semiconductor chip after removing the substrate 10 and laser absorption layer 14. The substrate 10, which is peeled off by laser processing, can also be reused.

[0028] [Structure of the control circuit chip]

[0029] like Figure 2 As shown, the control circuit chip 200 includes a substrate 20, a plurality of transistors 26 constituting the control circuit, and a circuit-side wiring layer 27. The plurality of transistors 26 are formed on the substrate 20 and electrically connected to the circuit-side wiring layer 27 on the side opposite to the substrate 20. Connection terminals for connecting to the memory cell array chip 100 are disposed on the connection surface C1 of the circuit-side wiring layer 27 on the side opposite to the substrate 20. The substrate 20 may also be a semiconductor wafer such as a silicon substrate.

[0030] [Laser processing equipment]

[0031] use Figure 4 and Figure 5 This embodiment describes the laser processing apparatus 300.

[0032] Figure 4 This is a top view showing the basic structure of a laser processing device. Figure 5 This is a side view showing the basic structure of a laser processing device. (For example...) Figure 4 and Figure 5 As shown, the laser processing apparatus 300 has a stage 32 and a laser irradiation device 35.

[0033] The stage 32 is circular, holding multiple semiconductor memory devices (attached substrates) 1 on concentric circles. Figure 4 In this configuration, the stage 32 holds eight semiconductor memory devices (attachment substrates) 1 on one circumference. However, the number of semiconductor memory devices (attachment substrates) 1 is not particularly limited, and they can also be arranged on the circumferences of different concentric circles. Preferably, the semiconductor memory devices (attachment substrates) 1 are arranged away from the center C of the concentric circles. The multiple semiconductor memory devices (attachment substrates) 1 are arranged with substrate 20 as the lower side (stage 32 side) and substrate 10 as the upper side (side opposite to substrate 32).

[0034] The stage 32 includes a rotating mechanism 33 and a control unit 39. The stage 32 rotates about a vertical axis containing a center C of concentric circles via the rotating mechanism 33. Figure 4 The arrow shows the direction of clockwise rotation of the stage 32, but it can also rotate counterclockwise. As the stage 32 rotates, the semiconductor memory device (attached substrate) 1 held by the stage 32 rotates about the center C in a circular orbit. The rotation of the stage 32, driven by the rotation mechanism 33, and its rotation speed are controlled by the control unit 39.

[0035] The stage 32 may also include a holding mechanism 34. The holding mechanism 34 is capable of holding the substrate 10, which has been peeled from the semiconductor memory device (attached substrate) 1 by laser processing, on the stage 32. Figure 4 In this embodiment, two holding mechanisms 34 are provided for each semiconductor memory device (attachment substrate) 1. The holding mechanisms 34 are located at the ends of the semiconductor memory device (attachment substrate) 1. However, the number and position of the holding mechanisms 34 provided for each semiconductor memory device (attachment substrate) 1 are not particularly limited. The holding mechanisms 34 are only required to be able to recover the peeled substrate 10 as long as they do not obstruct laser processing. The substrate 10, which is recovered without damage, can be reused through the holding mechanisms 34.

[0036] A laser irradiation device 35 is disposed above the stage 32. The laser irradiation device 35 irradiates the laser absorption layer 14 of the semiconductor memory device (attachment substrate) 1 with laser light. The laser irradiation device 35 irradiates a high-frequency pulsed laser light oscillated from a laser oscillator (not shown). The laser light is penetrable through the substrate 10. Therefore, by irradiating the substrate 10 side of the semiconductor memory device (attachment substrate) 1 with laser light, it is possible to concentrate the irradiation onto the laser absorption layer 14 located below the substrate 10. The laser light is preferably, for example, an infrared pulsed laser, and preferably a carbon dioxide gas laser (CO2 laser). The laser absorption layer 14 is ablated by the laser irradiation.

[0037] The laser irradiation device 35 includes a moving mechanism 36 and a control unit 38. The laser irradiation device 35 moves radially above the stage 32 via the moving mechanism 36. Figure 4 and Figure 5 The diagram shows the direction (arrow) in which the laser irradiation device 35 moves from the end of the stage 32 towards the center C, but it can also move from the center C of the stage 32 towards the end. The laser irradiation device 35 can move from at least one end of the semiconductor memory device (adhesive substrate) 1 to the other end (within a diameter range). By rotating the stage 32 while moving the laser irradiation device 35, the laser irradiation device 35 irradiates the semiconductor memory device (adhesive substrate) 1 arranged on the stage 32 with laser light. That is, the laser irradiation device 35 irradiates the semiconductor memory device (adhesive substrate) 1 arranged on the stage 32 with laser light along a striped track formed by concentric circular arcs. By making the semiconductor memory device (adhesive substrate) 1 far enough away from the center C of the stage 32, the track of the laser light irradiating the semiconductor memory device (adhesive substrate) 1 becomes a striped track arranged in a roughly straight line. The movement, speed, and laser output of the laser irradiation device 35 driven by the moving mechanism 36 are controlled by the control unit 38.

[0038] [Laser ablation method]

[0039] A laser lift-off method for removing the substrate 10 and the laser absorption layer 14 from a semiconductor memory device (bonding substrate) 1 using the laser processing apparatus 300 according to this embodiment will be described. The semiconductor memory device (semiconductor device) of the embodiment is manufactured using the laser lift-off method described below.

[0040] like Figure 4 and Figure 5As shown, multiple semiconductor memory devices (attachment substrates) 1 are arranged on the stage 32 with substrate 20 as the lower side (stage 32 side) and substrate 10 as the upper side (opposite to substrate 32). A laser irradiation device 35 is moved while the stage 32 is rotated, and the laser irradiation device 35 irradiates laser light along a vortex-shaped path relative to the stage 32. The laser light is focused onto the laser absorption layer 14 of the semiconductor memory device (attachment substrate) 1. The laser irradiation device 35 moves from at least one end of the semiconductor memory device (attachment substrate) 1 to the other end (within a diameter range).

[0041] Figure 6 This is an enlarged top view showing the laser irradiation area of ​​the semiconductor memory device (attached substrate) 1. Figure 6 yes Figure 2 The upper surface of the laser absorption layer 14 ( Figure 4 An enlarged top view of region a). As the stage 32 rotates, the continuously irradiated laser spots S move in the opposite direction (arrow) to the rotation direction of the stage 32. That is, the two continuously irradiated laser spots S are adjacent in the rotation direction of the stage 32. The interval L1 between the two continuously irradiated laser spots S is the linear velocity / frequency of the pulsed laser. Here, the interval L1 between the two laser spots S indicates the distance between the centers of the two laser spots S. The linear velocity of the pulsed laser refers to the moving speed (rotation speed) of the stage 32 at the position of the laser irradiation device 35, which is controlled by the control unit 39. The position of the laser irradiation device 35 and the frequency of the pulsed laser are controlled by the control unit 38.

[0042] In this embodiment, the interval L1 between two consecutively irradiated laser spots S is larger than the diameter x of the laser spot S (L1>x). That is, two adjacent laser spots S are spaced apart (L1-x) in the rotation direction of the stage 32. If the interval L1 between two laser spots S is smaller than the diameter x of the laser spot S, the laser spots S will become denser, which may sometimes damage the substrate 10. Here, the diameter x of the laser spot S represents the full width at half maximum (FWHM) of the laser spot S on the upper surface of the laser absorption layer 14. The diameter x of the laser spot is controlled by the control unit 38.

[0043] Preferably, the spacing L1 between all laser spot S is approximately the same. Therefore, it is preferable that the closer the position of the laser irradiation device 35 is to the center C, the greater the rotational speed of the stage 32. It is also preferable that the closer the position of the laser irradiation device 35 is to the center C, the smaller the frequency of the pulsed laser (the greater the period of the pulse).

[0044] During approximately one rotation of the stage 32, the laser irradiation device 35 moves towards the center C. That is, the laser spot S lagging behind by one rotation is adjacent to the laser spot S of the previous rotation in the radial direction of the stage 32. The interval L2 between two adjacent laser spots S in the direction of movement of the laser irradiation device 35 is the distance the laser irradiation device 35 moves during one rotation of the stage 32. Here, the interval L2 between the two laser spots S indicates the distance between the centers of the two laser spots S. The distance the laser irradiation device 35 moves during one rotation of the stage 32 is controlled by the control unit 38 according to the moving speed of the laser irradiation device 35.

[0045] In this embodiment, the distance L2 between two adjacent laser spots S in the moving direction of the laser irradiation device 35 is larger than the diameter x of the laser spot S (L2>x). That is, two adjacent laser spots S in the radial direction of the stage 32 are separated by (L2-x). If the distance L2 between two laser spots S is smaller than the diameter x of the laser spot S, the laser spots S will become denser, which may sometimes damage the substrate 10.

[0046] Preferably, the interval L2 between all laser spot S is approximately the same. Therefore, it is preferable that the moving speed of the laser irradiation device 35 is constant. However, it is not limited to this; the moving speed of the laser irradiation device 35 can also be increased while increasing the rotational speed of the stage 32 to keep the interval L1 between the laser spot S constant.

[0047] In this embodiment, it is more preferable that the interval L1 between two continuously irradiated laser spots S and the interval L2 between two adjacent laser spots S in the moving direction of the laser irradiation device 35 are approximately the same. That is, it is more preferable that the intervals L1 and L2 between the laser spots S are all equal.

[0048] In the laser lift-off method of this embodiment, by controlling the rotation speed of the stage 32 of the laser processing apparatus 300, the moving speed of the laser irradiation device 35, and the laser output (vibration frequency of the pulsed laser, diameter of the laser spot) of the laser irradiation device 35 by the control units 38 and 39, the interval L1, L2 of the laser spot S and the diameter x of the laser spot can be appropriately adjusted. By controlling the interval L1, L2 of the laser spot S and the diameter x of the laser spot within the above range, multiple semiconductor memory devices (bonding substrates) 1 can be irradiated with laser with high efficiency and uniformity, and the bonding force of the laser absorption layer 14 can be reduced to separate the substrate 10 from the semiconductor memory device (bonding substrate) 1. Therefore, the laser lift-off method of this embodiment can improve the manufacturing efficiency of the semiconductor memory device 2 and improve the reuse efficiency of the substrate 10.

[0049] Furthermore, in this embodiment, a configuration is shown in which two control units 38 and 39 respectively control the rotational speed of the stage 32 of the laser processing apparatus 300, the moving speed of the laser irradiation device 35, and the laser output (frequency of the pulsed laser and diameter of the laser spot) of the laser irradiation device 35. However, this is not a limitation; the rotational speed of the stage 32 of the laser processing apparatus 300, the moving speed of the laser irradiation device 35, and the laser output (frequency of the pulsed laser and diameter of the laser spot) of the laser irradiation device 35 can also be centrally controlled by a single control unit.

[0050] Furthermore, a configuration in which the laser irradiation device 35 oscillates to generate a single laser beam is shown. However, it is not limited to this configuration; the laser irradiation device 35 may also oscillate to generate multiple laser beams. In this case, the multiple laser beams may be arranged at intervals L2 in the radial direction of the stage 32, and the multiple laser beams may also be arranged at intervals equal to the radius of the semiconductor memory device (attachment substrate) 1 in the radial direction of the stage 32. By controlling the intervals L1 and L2 of the laser spot S within the aforementioned range, laser irradiation can be performed more effectively.

[0051] <Second Implementation Method>

[0052] The laser processing apparatus 300A according to this embodiment is identical in configuration to the laser processing apparatus 300 according to the first embodiment, except that it includes two laser irradiation devices 35a and 35b. Descriptions identical to those in the first embodiment are omitted; instead, descriptions will focus on the differences in configuration between this and the laser processing apparatus according to the first embodiment.

[0053] [Laser processing equipment]

[0054] use Figure 7 and Figure 8 This embodiment describes the laser processing apparatus 300A.

[0055] Figure 7 This is a top view showing the basic structure of a laser processing device. Figure 8 This is a side view showing the basic structure of a laser processing device. (For example...) Figure 7 and Figure 8 As shown, the laser processing apparatus 300A includes a stage 32 and two laser irradiation devices 35a and 35b. Furthermore, in this embodiment, the configuration with two laser irradiation devices 35a and 35b is described, but there may be two or more laser irradiation devices 35a and 35b.

[0056] Laser irradiation devices 35a and 35b each include moving mechanisms 36a and 36b and control units 38a and 38b. Laser irradiation devices 35a and 35b move independently in the radial direction above the stage 32 via their respective moving mechanisms 36a and 36b. Figure 7 and Figure 8 In this configuration, laser irradiation device 35a moves radially within region A, and laser irradiation device 35b moves radially within region B. Although the direction of movement of laser irradiation devices 35a and 35b from the end side of stage 32 towards the center C is shown (arrows), they can also move from the center C side of stage 32 towards the end side. Both laser irradiation devices 35a and 35b can move from at least one end of the semiconductor memory device (attached substrate) 1 to the other end (within a diameter range). By rotating stage 32 while moving laser irradiation devices 35a and 35b within their respective regions, laser irradiation devices 35a and 35b irradiate lasers relative to stage 32 along two spiral-shaped tracks. That is, laser irradiation device 35a irradiates lasers along a spiral-shaped track within region A. Laser irradiation device 35b irradiates lasers along a spiral-shaped track within region B. Laser irradiation devices 35a and 35b irradiate the semiconductor memory device (attachment substrate) 1, which is disposed on the stage 32, with laser light along a striped track formed by concentric circular arcs. Here, the laser irradiation devices 35a and 35b are positioned opposite each other, separated by the center C of the stage 32, but their positions are not particularly limited. The laser irradiation devices 35a and 35b only need not be adjacent on the circumference of a concentric circle, nor adjacent in the radial direction of the stage 32.

[0057] [Laser ablation method]

[0058] A laser stripping method for removing substrate 10 and laser absorption layer 14 from semiconductor memory device (bonding substrate) 1 using the laser processing apparatus 300A according to this embodiment will be described.

[0059] like Figure 7 and Figure 8 As shown, multiple semiconductor memory devices (attachment substrates) 1 are arranged on the stage 32 with the substrate 20 as the lower side (side of the stage 32) and the substrate 10 as the upper side (the side opposite to the substrate 32). While rotating the stage 32, the laser irradiation devices 35a and 35b are moved, irradiating laser light along two spiral tracks relative to the stage 32. The laser light is focused onto the laser absorption layer 14 of the semiconductor memory device (attachment substrate) 1. The laser irradiation device 35a moves within region A of the semiconductor memory device (attachment substrate) 1 (the area outside the center of the semiconductor memory device (attachment substrate) 1). The laser irradiation device 35b moves within region B of the semiconductor memory device (attachment substrate) 1 (the area inside the center of the semiconductor memory device (attachment substrate) 1).

[0060] Figure 9This is an enlarged top view showing the laser irradiation area of ​​the semiconductor memory device (attached substrate) 1. Figure 9 yes Figure 7 Enlarged top views of regions a and b. As the stage 32 rotates, the two continuously irradiated laser spots Sa and Sb move in the opposite direction (arrow) to the rotation direction of the stage 32.

[0061] In the laser ablation method of this embodiment, by controlling the rotation speed of the stage 32 of the laser processing apparatus 300A, the moving speed of the laser irradiation device 35a, and the laser output (frequency of the pulsed laser, diameter of the laser spot) of the laser irradiation device 35a, the control units 38a and 39 can appropriately adjust the diameter xa of the laser spot in region a, the interval La1 between two consecutively irradiated laser spots Sa, and the interval La2 between two adjacent laser spots Sa in the moving direction of the laser irradiation device 35a, in the same manner as in the first embodiment. By controlling the rotation speed of the stage 32 of the laser processing apparatus 300A, the moving speed of the laser irradiation device 35b, and the laser output (frequency of the pulsed laser, diameter of the laser spot) of the laser irradiation device 35b, the control units 38b and 39 can appropriately adjust the diameter xb of the laser spot in region b, the interval Lb1 between two consecutively irradiated laser spots Sb, and the interval Lb2 between two adjacent laser spots Sb in the moving direction of the laser irradiation device 35b, in the same manner as in the first embodiment. Therefore, repeated descriptions are omitted.

[0062] In this embodiment, it is preferable that the diameter xa of the laser spot in region a and the diameter xb of the laser spot in region b are approximately the same. The diameters xa and xb of the laser spots are controlled by control units 38a and 38b respectively.

[0063] Preferably, the interval La1 between two laser spots Sa continuously irradiated in region a is approximately the same as the interval Lb1 between two laser spots Sb continuously irradiated in region b. Therefore, it is preferable that the frequency of the pulsed laser (increasing the period of the pulse) is reduced compared to the laser irradiation device 35a, which is farther from the center C, and the laser irradiation device 35b is farther from the center C. The frequencies of the pulsed lasers of the laser irradiation devices 35a and 35b are controlled by control units 38a and 38b, respectively.

[0064] In preferred region a, the distance La2 between two adjacent laser spots Sa in the moving direction of the laser irradiation device 35a is approximately the same as the distance Lb2 between two adjacent laser spots Sb in the moving direction of the laser irradiation device 35b. Therefore, it is preferable that the moving speeds of the laser irradiation devices 35a and 35b are approximately the same.

[0065] In this embodiment, it is more preferable that the intervals La1 and Lb1 between two continuously irradiated laser spots Sa and Sb are approximately the same as the intervals La2 and Lb2 between two adjacent laser spots Sa and Sb in the moving direction of the laser irradiation devices 35a and 35b. That is, it is more preferable that the intervals La1, Lb1, La2, and Lb2 between the laser spots Sa and Sb are all equal.

[0066] By controlling the intervals La1, Lb1, La2, Lb2 of the laser spots Sa and Sb, and the diameters xa and xb of the laser spots within the aforementioned ranges, multiple semiconductor memory devices (attached substrates) 1 can be efficiently and uniformly irradiated with laser light. This reduces the bonding force of the laser absorption layer 14, allowing the substrate 10 to be separated from the semiconductor memory device (attached substrate) 1. Therefore, the laser lift-off method according to this embodiment can improve the manufacturing efficiency of the semiconductor memory device 2 and increase the reuse efficiency of the substrate 10.

[0067] Furthermore, in this embodiment, a configuration is shown in which three control units 38a, 38b, and 39 respectively control the rotational speed of the stage 32 of the laser processing apparatus 300A, the moving speed of the laser irradiation devices 35a and 35b, and the laser output (frequency of the pulsed laser and diameter of the laser spot) of the laser irradiation devices 35a and 35b. However, this is not a limitation; the rotational speed of the stage 32 of the laser processing apparatus 300A, the moving speed of the laser irradiation devices 35a and 35b, and the laser output (frequency of the pulsed laser and diameter of the laser spot) of the laser irradiation devices 35a and 35b can also be centrally controlled by a single control unit.

[0068] Furthermore, a configuration is shown in which the laser irradiation devices 35a and 35b move in different regions A and B. However, this is not a limitation; both laser irradiation devices 35a and 35b can be configured to move in the same region as in the first embodiment. In this case, the positions of the laser irradiation devices 35a and 35b are offset by L2 in the radial direction of the stage 32, and the moving speeds of the laser irradiation devices 35a and 35b are each twice that of the first embodiment. With this configuration, the laser irradiation tracks of the laser irradiation devices 35a and 35b can be such that the vortex of one is nested between the vortices of the other, and the laser is irradiated uniformly without the two tracks intersecting.

Claims

1. A method for manufacturing a semiconductor device, comprising the following steps: Multiple first-bonded substrates, formed by bonding a first substrate and a second substrate together with a first laser absorption layer, are arranged on the concentric circles of the stage. Rotate the stage about the center of the concentric circles as an axis; The laser irradiation device that irradiates the first laser absorption layer with infrared pulsed laser is moved in the radial direction of the concentric circles. Peel off the second substrate; as well as Multiple second bonded substrates, formed by bonding the peeled second substrate and the third substrate through a second laser absorption layer, are arranged on the concentric circles of the stage.

2. The method for manufacturing a semiconductor device according to claim 1, wherein, The first laser absorption layer is disposed between the first substrate and the second substrate, and is closer to the second substrate than to the first substrate. The plurality of first bonding substrates are located closer to the outer side of the stage than the center of the stage. The closer the laser irradiation device is to the center, the greater the rotational speed of the stage, or the smaller the frequency of the infrared pulsed laser. By increasing the rotational speed of the stage, the moving speed of the laser irradiation device is also increased.

3. The method for manufacturing a semiconductor device according to claim 1, wherein, The second substrate is a silicon substrate. The first laser absorption layer is a silicon oxide film. The first laser absorption layer is disposed between the first substrate and the second substrate, and is closer to the second substrate than to the first substrate.

4. The method for manufacturing a semiconductor device according to claim 1, wherein, The method for manufacturing the semiconductor device is configured such that, during the movement of the laser irradiation device along the radial direction, the plurality of first bonding substrates disposed on the concentric circles are rotated, thereby enabling the laser irradiation device to irradiate the infrared pulsed laser along a vortex-shaped track relative to the stage.

5. The method for manufacturing a semiconductor device according to claim 1, wherein, The first bonding substrate includes a CMOS circuit, a memory cell array, and a first laser absorption layer between the first substrate and the second substrate, and is irradiated with the infrared pulsed laser from the second substrate side.

6. A method for manufacturing a semiconductor device, comprising the following steps: Multiple bonded substrates, formed by bonding the first substrate and the second substrate with a laser absorption layer in between, are arranged on the concentric circles of the stage. Rotate the stage about the center of the concentric circles as an axis; The laser irradiation device that irradiates the laser absorption layer with infrared pulsed laser is moved in the radial direction of the concentric circles. as well as Peel off the second substrate. The plurality of bonding substrates are located closer to the outer side of the stage than the center of the stage. The closer the laser irradiation device is to the center, the greater the rotational speed of the stage, or the smaller the frequency of the infrared pulsed laser. By increasing the rotational speed of the stage, the moving speed of the laser irradiation device is also increased.

7. The method for manufacturing a semiconductor device according to claim 6, wherein, The second substrate is a silicon substrate. The laser absorption layer is a silicon oxide film. The laser absorption layer is disposed between the first substrate and the second substrate, and is closer to the second substrate than the first substrate.

8. The manufacturing method of the semiconductor device according to claim 6, wherein The semiconductor device includes a memory cell array chip and a control circuit chip connected to the memory cell array chip. The memory cell array chip has the second substrate. The control circuit chip has the first substrate.

9. The manufacturing method of the semiconductor device according to claim 6, wherein The manufacturing method of the semiconductor device is configured such that during the movement of the laser irradiation device in the radial direction, by rotating the plurality of bonded substrates arranged on the concentric circles, the laser irradiation device can irradiate the infrared pulsed laser along a spiral orbit with respect to the stage.

10. The manufacturing method of the semiconductor device according to claim 6, wherein The bonded substrate includes a CMOS circuit, a memory cell array, and the laser absorption layer between the first substrate and the second substrate, and the infrared pulsed laser is irradiated from the second substrate side.

11. A laser processing device, comprising: A stage that holds a plurality of bonded substrates each having a first substrate and a second substrate on concentric circles and rotates about the center of the concentric circles; and A first laser irradiation device that has a control unit and can move in the radial direction of the concentric circles, and the control unit controls the output of the infrared pulsed laser so that adjacent laser spots are separated. The stage further includes a holding mechanism that can hold the second substrate peeled off from the plurality of bonded substrates on the stage.

12. The laser processing device according to claim 11, wherein The holding mechanism is provided on the concentric circles on the stage.

13. The laser processing device according to claim 12, wherein The holding mechanism can hold two points on the diameter of the bonded substrate.

14. The laser processing device according to claim 11, wherein The holding mechanism is not provided between the bonded substrate and the stage.

15. The laser processing device according to claim 11, wherein The laser processing device is configured such that during the movement of the first laser irradiation device in the radial direction, by rotating the plurality of substrates held on the concentric circles, the first laser irradiation device can irradiate the plurality of laser spots along a spiral orbit with respect to the stage.

16. The laser processing device according to claim 11, wherein When the diameter of the plurality of laser spots is x and the interval between the plurality of adjacent laser spots in the rotation direction of the stage is L1, the control unit controls in such a manner that x < L1. When the diameter of the laser spot is x and the interval between the plurality of adjacent laser spots in the moving direction of the laser irradiation device is L2, the control unit controls in such a manner that x < L2.

17. The laser processing apparatus according to claim 11, wherein, The closer the laser irradiation device is to the center, the more the control unit increases the rotation speed of the stage or decreases the frequency of the infrared pulse laser. By increasing the rotational speed of the stage, the moving speed of the laser irradiation device is also increased.

18. The laser processing apparatus according to claim 11, wherein, It also has a second laser irradiation device. The first laser irradiation device and the second laser irradiation device move in the radial direction of the concentric circles, respectively.

19. The laser processing apparatus according to claim 18, wherein, The first laser irradiation device and the second laser irradiation device respectively output infrared pulse lasers with different frequencies.

20. The laser processing apparatus according to claim 18, wherein, With the center of the concentric circles as the center, the positions of the first laser irradiation device and the second laser irradiation device are not adjacent on the circumference of the same concentric circle, nor are they adjacent in the radial direction of the circle. The control unit controls the first laser irradiation device to irradiate laser along a vortex-shaped track in a first region outside the center of each of the plurality of bonding substrates, and the second laser irradiation device to irradiate laser along a vortex-shaped track in a second region inside the center of each of the plurality of bonding substrates and not overlapping with the first region. Furthermore, the infrared pulse laser frequency is reduced when the second laser irradiation device, which is closer to the center of the concentric circles, is closer to the center of the concentric circles than when the first laser irradiation device, which is farther from the center of the concentric circles.

21. A laser ablation method, comprising the following steps: Multiple bonded substrates, formed by bonding the first substrate and the second substrate with a laser absorption layer in between, are arranged on the concentric circles of the stage. Rotate the stage about the center of the concentric circles as an axis; as well as The laser irradiation device that irradiates the laser absorption layer with infrared pulsed laser light is moved along the radial direction of the concentric circles. The plurality of bonding substrates are located closer to the outer side of the stage than the center of the stage. The closer the laser irradiation device is to the center, the greater the rotational speed of the stage, or the smaller the frequency of the infrared pulsed laser. By increasing the rotational speed of the stage, the moving speed of the laser irradiation device is also increased.

22. The laser ablation method according to claim 21, wherein, The laser stripping method is configured such that, during the movement of the laser irradiation device along the radial direction, the plurality of bonding substrates disposed on the concentric circles are rotated, thereby enabling the laser irradiation device to irradiate the infrared pulsed laser along a vortex-shaped track relative to the stage.

23. The laser ablation method according to claim 21, wherein, The laser irradiation device controls the output of the infrared pulsed laser by separating multiple adjacent laser spots.

24. The laser ablation method according to claim 23, wherein, When the diameter of the plurality of laser light spots is x and the distance between the plurality of adjacent laser light spots in the rotational direction of the stage is L1, the laser irradiation device is controlled such that x < L1. When the diameter of the plurality of laser light spots is x and the distance between the plurality of adjacent laser light spots in the moving direction of the laser irradiation device is L2, the laser irradiation device is controlled such that x < L2. [[ID={25}]]25. The laser lift-off method according to claim 21, wherein the second substrate is a silicon substrate, the laser absorption layer is a silicon oxide film, the laser absorption layer is provided between the first substrate and the second substrate and is closer to the second substrate than the first substrate.

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