Laser processing device, laser peeling method, and semiconductor device manufacturing method

Abstract

To improve manufacturing efficiency of a semiconductor memory device and to improve reuse efficiency of the substrate.SOLUTION: A laser processing apparatus according to one embodiment has a stage that holds a plurality of substrates in concentric circles and rotates about the center of the concentric circles, and a laser irradiation device that has a control unit that controls output of an infrared pulse laser so that a plurality of adjacent laser spots is spaced apart and that can move in a radial direction of the concentric circles. The control unit may control the plurality of laser spots to satisfy x<L1 when a diameter of the plurality of laser spots is x and a space between the plurality of adjacent laser spots in a direction of rotation of the stage is L1.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] Embodiments of the present disclosure relate to a laser processing apparatus, a laser peeling method, and a method for manufacturing a semiconductor device. [Background technology]

[0002] NAND flash memory is a well-known type of semiconductor memory device. This NAND flash memory includes a memory cell array and its control circuit. One known method for manufacturing semiconductor memory devices is to form a memory cell array chip and a control circuit chip on separate 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 peeling. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2019 / 239892 [Patent Document 2] International Publication No. 2020 / 017599 [Patent Document 3] International Publication No. 2020 / 054504 [Patent Document 4] International Publication No. 2020 / 066492 [Patent Document 5] Patent No. 3908129 [Patent Document 6] Patent No. 5357561 [Patent Document 7] Japanese Patent Application Laid-Open No. 2014-053510 Summary of the Invention [Problem to be solved by the invention]

[0004] The embodiments according to the present disclosure provide a laser processing apparatus, a laser separation method, and a method for manufacturing a semiconductor device that improve the manufacturing efficiency of semiconductor memory devices and also improve the reuse efficiency of substrates. [Means for solving the problem]

[0005] The laser processing apparatus of this embodiment has a stage that holds multiple substrates on a concentric circle and rotates around the center of the concentric circle as an axis, a control unit that controls the output of an infrared pulse laser so that multiple adjacent laser spots are spaced apart, and a laser irradiation device that can be moved in the radial direction of the concentric circle. [Brief explanation of the drawings]

[0006] [Figure 1] 1 is a diagram showing the overall configuration of a semiconductor memory device (bonded substrate) according to an embodiment of the present invention. [Figure 2] 1 is a cross-sectional view showing the configuration of a semiconductor memory device (bonded substrate) according to the present embodiment. [Figure 3] 1 is a diagram showing the overall configuration of a semiconductor memory device according to an embodiment of the present invention; [Figure 4] 1 is a top view showing the basic configuration of a laser processing apparatus according to an embodiment of the present invention. [Figure 5] 1 is a side view showing a basic configuration of a laser processing apparatus according to an embodiment of the present invention. [Figure 6] FIG. 2 is an enlarged top view showing a laser irradiation area (laser spot) of the semiconductor memory device (bonded substrate) 1 according to the present embodiment. [Figure 7] 1 is a top view showing the basic configuration of a laser processing apparatus according to an embodiment of the present invention. [Figure 8] 1 is a side view showing a basic configuration of a laser processing apparatus according to an embodiment of the present invention. [Figure 9] FIG. 2 is an enlarged top view showing a laser irradiation area (laser spot) of the semiconductor memory device (bonded substrate) 1 according to the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0007] The laser processing apparatus and laser peeling method according to the present embodiment will be specifically described below with reference to the drawings. In the following description, elements having substantially the same function and configuration are designated by the same reference numeral or a reference numeral with an alphabet added thereto, and will be described repeatedly only when necessary. The following embodiments exemplify apparatuses and methods for embodying the technical concept of the embodiments. The technical concept of the embodiments is not limited to the materials, shapes, structures, arrangements, etc. of the components described below. The technical concept of the embodiments may be modified in various ways within the scope of the claims.

[0008] In order to clarify the description, the drawings may show the width, thickness, shape, etc. of each part schematically compared to the actual embodiment, but these are merely examples and do not limit the interpretation of the present invention. In this specification and each drawing, elements having the same functions as those explained with reference to the previous drawings may be assigned the same reference numerals, and duplicate explanations may be omitted.

[0009] 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 the respective substrate is referred to as "downward." While the terms "upward" and "downward" are used for convenience of explanation, for example, the vertical relationship between the substrate and the memory cell may be reversed from that illustrated. Furthermore, in the following explanation, for example, the expression "memory cell on a substrate" merely describes the vertical relationship between the substrate and the memory cell as described above, and other components may be disposed between the substrate and the memory cell.

[0010] In this specification, unless otherwise specified, expressions such as "α is A, B, or C," "α is any one of A, B, and C," and "α is one selected from the group consisting of A, B, and C" do not exclude cases where α includes multiple combinations of A to C. Furthermore, these expressions do not exclude cases where α includes other elements.

[0011] The following embodiments can be combined with each other unless a technical contradiction occurs.

[0012] First Embodiment [Semiconductor memory device (bonded substrate)] The configuration of a semiconductor memory device (bonded substrate) 1 according to this embodiment will be described with reference to FIGS. 1 to 3. FIG. 1 is a diagram showing the overall configuration of the semiconductor memory device (bonded substrate) 1. FIG. 2 is a cross-sectional view showing the basic configuration of the semiconductor memory device (bonded substrate) 1. FIG. 3 is a diagram showing the overall configuration of a semiconductor memory device 2. As shown in FIG. 1, the semiconductor memory device (bonded 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. The first circuit layer and the second circuit layer are not particularly limited. Therefore, the semiconductor memory device according to the embodiment may be referred to as a "semiconductor device."

[0013] [Memory cell array chip structure] As shown in FIG. 2, the memory cell array chip 100 includes a substrate 10, a laser absorption layer 14, multiple electrode layers 16, multiple semiconductor pillars 15, and a memory-side wiring layer 17. The multiple electrode layers 16 are alternately stacked with multiple insulating layers on the substrate 10 via the laser absorption layer 14. Each semiconductor pillar 15 is disposed perpendicular to the substrate 10, penetrating the stacked multiple electrode layers 16. Each semiconductor pillar 15 is combined with the multiple electrode layers 16 via the insulating layers to function as multiple transistors including memory cells. That is, in the memory cell array region 11 (the upper left part of FIG. 2), multiple transistors including memory cells are three-dimensionally arranged. One end of the semiconductor pillar 15 (on the substrate 10 side) is electrically connected to a source line, and the other end (on the opposite side from the substrate 10) is electrically connected to the memory-side wiring layer 17. A connection terminal for connecting to the control circuit chip 200 is disposed on a connection surface C1 of the memory-side wiring layer 17 opposite to the substrate 10.

[0014] On the substrate 10, a lead-out region 12 (the upper right part of FIG. 2) is arranged alongside the memory cell array region 11. In the lead-out region 12, terminal portions of each of the multiple electrode layers 16 are led out in a stepped manner. Each terminal portion is connected to vertical wiring via contact holes opened in the insulating film. These vertical wirings are electrically connected to the memory-side wiring layer 17, and are connected to the control circuit chip 200 via connection terminals.

[0015] The substrate 10 may be a semiconductor wafer such as a silicon substrate or a glass substrate. A laser absorbing layer 14 is disposed between the substrate 10 and the plurality of electrode layers 16. As shown in FIG. 3 , the substrate 10 and the laser absorbing layer 14 of the semiconductor memory device (bonded substrate) 1 according to this embodiment are finally removed from the semiconductor memory device 2 by irradiating the laser absorbing layer 14 with a laser during the manufacturing process of the semiconductor memory device. The laser absorbing layer 14 is preferably, for example, a silicon oxide film. After removing the substrate 10 and the laser absorbing layer 14, the semiconductor memory device 2 may be singulated into individual semiconductor chips. The substrate 10 peeled off by laser processing may be reused.

[0016] [Control circuit chip structure] 2, the control circuit chip 200 has a substrate 20, a plurality of transistors 26 that constitute a control circuit, and a circuit-side wiring layer 27. The plurality of transistors 26 are formed on the substrate 20 and are 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 arranged on a connection surface C1 of the circuit-side wiring layer 27 on the side opposite to the substrate 20. The substrate 20 may be a semiconductor wafer such as a silicon substrate.

[0017] [Laser processing equipment] The laser processing apparatus 300 according to this embodiment will be described with reference to FIGS.

[0018] Fig. 4 is a top view showing the basic configuration of the laser processing apparatus. Fig. 5 is a side view showing the basic configuration of the laser processing apparatus. As shown in Figs. 4 and 5, the laser processing apparatus 300 includes a stage 32 and a laser irradiation device 35.

[0019] The stage 32 is circular and holds multiple semiconductor memory devices (bonded substrates) 1 on concentric circles. In FIG. 4, the stage 32 holds eight semiconductor memory devices (bonded substrates) 1 on one circumference. However, the number of semiconductor memory devices (bonded substrates) 1 is not particularly limited, and they may be arranged on the circumference of different concentric circles. It is preferable that the semiconductor memory devices (bonded substrates) 1 are arranged away from the center C of the concentric circles. The multiple semiconductor memory devices (bonded substrates) 1 are arranged with the substrate 20 facing downward (toward the stage 32) and the substrate 10 facing upward (opposite the substrate 32).

[0020] The stage 32 includes a rotation mechanism 33 and a control unit 39. The stage 32 is rotated by the rotation mechanism 33 around a vertical axis including the center C of the concentric circle. In FIG. 4, the direction (arrow) of rotation of the stage 32 is shown as clockwise, but it may also rotate counterclockwise. As the stage 32 rotates, the semiconductor memory device (bonded substrate) 1 held by the stage 32 rotates around the circumference of a circle around the center C. The rotational movement and rotation speed of the stage 32 driven by the rotation mechanism 33 are controlled by the control unit 39.

[0021] The stage 32 may include a holding mechanism 34. The holding mechanism 34 can hold, on the stage 32, the substrate 10 that has been peeled off from the semiconductor memory device (bonded substrate) 1 by laser processing. In FIG. 4, two holding mechanisms 34 are provided for each semiconductor memory device (bonded substrate) 1. The holding mechanisms 34 are provided at the end of the semiconductor memory device (bonded substrate) 1. However, the number and location of the holding mechanisms 34 per semiconductor memory device (bonded substrate) 1 are not particularly limited. It is sufficient that the holding mechanism 34 does not interfere with the laser processing and is able to recover the peeled substrate 10. The substrate 10 recovered without damage by the holding mechanism 34 can be reused.

[0022] 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 (bonded substrate) 1 with a laser. The laser irradiation device 35 irradiates a high-frequency pulsed laser oscillated from a laser oscillator (not shown). The laser is transparent to the substrate 10. Therefore, by irradiating the semiconductor memory device (bonded substrate) 1 with a laser from the substrate 10 side, the laser can be focused and irradiated onto the laser absorption layer 14 located below the substrate 10. The laser is preferably, for example, an infrared pulse laser, and more preferably a carbon dioxide laser (CO2 laser). The laser irradiation causes ablation of the laser absorption layer 14.

[0023] The laser irradiation device 35 includes a moving mechanism 36 and a control unit 38. The laser irradiation device 35 is moved radially above the stage 32 by the moving mechanism 36. In FIGS. 4 and 5, the laser irradiation device 35 moves from the end of the stage 32 toward the center C (arrow), but it may also move from the center C toward the end of the stage 32. The laser irradiation device 35 can move at least from one end of the semiconductor memory device (bonded substrate) 1 to the other (within the diameter range). As the laser irradiation device 35 moves while the stage 32 rotates, the laser irradiation device 35 irradiates the stage 32 with a laser along a spiral trajectory. In other words, the laser irradiation device 35 irradiates the semiconductor memory device (bonded substrate) 1 placed on the stage 32 with a laser along a striped trajectory consisting of a series of concentric arcs. When the semiconductor memory device (bonded substrate) 1 is sufficiently far from the center C of the stage 32, the trajectory of the laser irradiated onto the semiconductor memory device (bonded substrate) 1 becomes a striped trajectory consisting of a series of approximately straight lines. The movement and speed of the laser irradiation device 35 driven by the movement mechanism 36, and the laser output of the laser irradiation device 35 are controlled by a control unit 38.

[0024] [Laser peeling method] A laser peeling method will be described below, in which the laser processing apparatus 300 according to this embodiment is used to remove the substrate 10 and the laser absorption layer 14 from the semiconductor memory device (bonded substrate) 1. The semiconductor memory device (semiconductor device) of the embodiment is manufactured using the laser peeling method described below.

[0025] As shown in Figures 4 and 5, multiple semiconductor memory devices (bonded substrates) 1 are placed on a stage 32 with substrate 20 facing downward (toward stage 32) and substrate 10 facing upward (opposite substrate 32). By moving a laser irradiation device 35 while rotating the stage 32, the laser irradiation device 35 irradiates the stage 32 with a laser along a spiral trajectory. The laser is focused and irradiated onto the laser absorption layer 14 of the semiconductor memory device (bonded substrate) 1. The laser irradiation device 35 is moved at least from one end of the semiconductor memory device (bonded substrate) 1 to the other (within the range of its diameter).

[0026] FIG. 6 is an enlarged top view showing the laser irradiation area of ​​the semiconductor memory device (bonded substrate) 1. FIG. 6 is an enlarged top view of the upper surface of the laser absorption layer 14 in FIG. 2 (area a in FIG. 4). As the stage 32 rotates, the continuously irradiated laser spots S move in the direction opposite to the rotation direction of the stage 32 (indicated by the arrow). That is, the two continuously irradiated laser spots S are adjacent to each other 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 refers to the distance between the centers of the two laser spots S. The linear velocity of the pulsed laser is the moving speed (rotational speed) of the stage 32 at the position of the laser irradiation device 35, and 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.

[0027] In this embodiment, the interval L1 between two successively irradiated laser spots S is larger than the diameter x of the laser spot S (L1>x). That is, two adjacent laser spots S in the rotation direction of the stage 32 are spaced apart by (L1-x). If the interval L1 between the two laser spots S is smaller than the diameter x of the laser spots S, the laser spots S will be too close together, which may damage the substrate 10. Here, the diameter x of the laser spot S refers to the full width at half maximum 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.

[0028] It is preferable that the intervals L1 between all of the laser spots S are approximately the same. Therefore, it is preferable to increase the rotation speed of the stage 32 as the position of the laser irradiation device 35 approaches the center C. It is preferable to decrease the frequency of the pulse laser (increase the pulse period) as the position of the laser irradiation device 35 approaches the center C.

[0029] While the stage 32 rotates approximately one revolution, the laser irradiation device 35 moves toward the center C. In other words, the laser spot S of the later revolution is adjacent to the laser spot S of the previous revolution in the radial direction of the stage 32. The interval L2 between two adjacent laser spots S in the movement direction of the laser irradiation device 35 is the movement distance of the laser irradiation device 35 while the stage 32 rotates one revolution. Here, the interval L2 between the two laser spots S refers to the distance between the centers of the two laser spots S. The movement distance of the laser irradiation device 35 while the stage 32 rotates one revolution is controlled by the control unit 38 based on the movement speed of the laser irradiation device 35.

[0030] In this embodiment, the interval L2 between two adjacent laser spots S in the movement direction of the laser irradiation device 35 is larger than the diameter x of the laser spots S (L2>x). That is, the two adjacent laser spots S in the radial direction of the stage 32 are spaced apart by (L2-x). If the interval L2 between the two laser spots S is smaller than the diameter x of the laser spots S, the laser spots S will be too close together, which may damage the substrate 10.

[0031] It is preferable that the intervals L2 between all of the laser spots S are substantially the same. Therefore, it is preferable that the movement speed of the laser irradiation device 35 is constant. However, this is not limiting, and if the rotation speed of the stage 32 is increased in order to keep the intervals L1 between the laser spots S constant, the movement speed of the laser irradiation device 35 may be increased.

[0032] In this embodiment, it is more preferable that the interval L1 between two laser spots S that are successively irradiated is substantially the same as the interval L2 between two laser spots S that are adjacent in the movement direction of the laser irradiation device 35. In other words, it is more preferable that the intervals L1 and L2 between the laser spots S are all equal.

[0033] In the laser delamination method according to this embodiment, the rotation speed of stage 32 of laser processing apparatus 300, the movement speed of laser irradiation device 35, and the laser output (pulse laser frequency, laser spot diameter) of laser irradiation device 35 are controlled by control units 38 and 39, thereby appropriately adjusting the spacing L1, L2 of laser spots S and the laser spot diameter x. By controlling the spacing L1, L2 of laser spots S and the laser spot diameter x within the above-described ranges, the laser can be efficiently and uniformly irradiated onto multiple semiconductor memory devices (bonded substrates) 1, reducing the bonding strength of laser absorption layer 14 and separating substrate 10 from semiconductor memory device (bonded substrate) 1. Therefore, the laser delamination method according to this embodiment can improve the manufacturing efficiency of semiconductor memory devices 2 and the reuse efficiency of substrate 10.

[0034] In this embodiment, the configuration has been shown in which two control units 38 and 39 respectively control the rotation speed of the stage 32 of the laser processing apparatus 300, the movement speed of the laser irradiation device 35, and the laser output (pulse laser frequency, laser spot diameter) of the laser irradiation device 35. However, without being limited to this, the rotation speed of the stage 32 of the laser processing apparatus 300, the movement speed of the laser irradiation device 35, and the laser output (pulse laser frequency, laser spot diameter) of the laser irradiation device 35 may be integrally controlled by a single control unit.

[0035] Also, the laser irradiation device 35 has been shown configured to emit one laser beam. However, the present invention is not limited to this, and the laser irradiation device 35 may be configured to emit multiple laser beams. In this case, the multiple laser beams may be arranged at intervals of L2 in the radial direction of the stage 32, or the multiple laser beams may be arranged at intervals of the radius of the semiconductor memory device (bonded substrate) 1 in the radial direction of the stage 32. By controlling the intervals L1 and L2 of the laser spots S within the above-mentioned ranges, the laser can be irradiated more efficiently.

[0036] Second Embodiment The configuration of the laser processing apparatus 300A according to this embodiment is the same as the configuration of the laser processing apparatus 300 according to the first embodiment, except that it is equipped with two laser irradiation devices 35a and 35b. Explanations of the same things as in the first embodiment will be omitted, and only the parts that differ from the configuration of the laser processing apparatus according to the first embodiment will be explained here.

[0037] [Laser processing equipment] A laser processing apparatus 300A according to this embodiment will be described with reference to FIGS.

[0038] Fig. 7 is a top view showing the basic configuration of the laser processing apparatus. Fig. 8 is a side view showing the basic configuration of the laser processing apparatus. As shown in Figs. 7 and 8, the laser processing apparatus 300A includes a stage 32 and two laser irradiation devices 35a and 35b. Although the present embodiment describes a configuration including two laser irradiation devices 35a and 35b, the number of laser irradiation devices 35 may be two or more.

[0039] The laser irradiation devices 35a and 35b each include a moving mechanism 36a and 36b and a control unit 38a and 38b. The laser irradiation devices 35a and 35b are independently moved radially above the stage 32 by their respective moving mechanisms 36a and 36b. In FIGS. 7 and 8, the laser irradiation device 35a moves radially within region A, and the laser irradiation device 35b moves radially within region B. While the direction of movement (arrows) of the laser irradiation devices 35a and 35b from the edge of the stage 32 toward the center C is shown, they may also move from the center C toward the edge of the stage 32. The two laser irradiation devices 35a and 35b can move at least from one end to the other (within the diameter range) of the semiconductor memory device (bonded substrate) 1. As the stage 32 rotates, the laser irradiation devices 35a and 35b move within their respective regions, causing the laser irradiation devices 35a and 35b to irradiate the stage 32 with laser light along two spiral trajectories. That is, the laser irradiation device 35a irradiates a laser along a spiral trajectory within region A. The laser irradiation device 35b irradiates a laser along a spiral trajectory within region B. The laser irradiation devices 35a and 35b irradiate the semiconductor memory device (bonded substrate) 1 placed on the stage 32 with a laser along a striped trajectory consisting of a series of concentric arcs. Here, the laser irradiation devices 35a and 35b are placed at positions facing each other across the center C of the stage 32, but the positions of the laser irradiation devices 35a and 35b are not particularly limited. The positions of the laser irradiation devices 35a and 35b need not be adjacent on the circumference of one concentric circle, and need not be adjacent in the radial direction of the stage 32.

[0040] [Laser peeling method] A laser peeling method for removing the substrate 10 and the laser absorption layer 14 from the semiconductor memory device (bonded substrate) 1 using the laser processing device 300A according to this embodiment will be described.

[0041] As shown in FIGS. 7 and 8, multiple semiconductor memory devices (bonded substrates) 1 are placed on a stage 32 with the substrate 20 facing downward (toward the stage 32) and the substrate 10 facing upward (opposite the substrate 32). By moving the laser irradiation devices 35a and 35b while rotating the stage 32, the laser irradiation devices 35a and 35b irradiate the stage 32 with laser light along two spiral trajectories. The laser light is focused and irradiated onto the laser absorption layer 14 of the semiconductor memory device (bonded substrate) 1. The laser irradiation device 35a moves within region A of the semiconductor memory device (bonded substrate) 1 (the range outside the center of the semiconductor memory device (bonded substrate) 1). The laser irradiation device 35b moves within region B of the semiconductor memory device (bonded substrate) 1 (the range inside the center of the semiconductor memory device (bonded substrate) 1).

[0042] Fig. 9 is an enlarged top view showing the laser irradiation area of ​​the semiconductor memory device (bonded substrate) 1. Fig. 9 is an enlarged top view of area a and area b in Fig. 7. As the stage 32 rotates, the two successively irradiated laser spots Sa and Sb each move in the direction opposite to the rotation direction of the stage 32 (indicated by the arrows).

[0043] In the laser peeling method according to this embodiment, the rotation speed of the stage 32 of the laser processing apparatus 300A, the movement speed of the laser irradiator 35a, and the laser output (pulse laser frequency, laser spot diameter) of the laser irradiator 35a are controlled by the control units 38a and 39, whereby the diameter xa of the laser spot in the region a, the interval La1 between two successively irradiated laser spots Sa, and the interval La2 between two adjacent laser spots Sa in the movement direction of the laser irradiator 35a can be appropriately adjusted in the same manner as in the first embodiment. The rotation speed of the stage 32 of the laser processing apparatus 300A, the movement speed of the laser irradiator 35b, and the laser output (pulse laser frequency, laser spot diameter) of the laser irradiator 35b are controlled by the control units 38b and 39, whereby the diameter xb of the laser spot in the region b, the interval Lb1 between two successively irradiated laser spots Sb, and the interval Lb2 between two adjacent laser spots Sb in the movement direction of the laser irradiator 35b can be appropriately adjusted in the same manner as in the first embodiment. Therefore, repeated explanation will be omitted.

[0044] In this embodiment, it is preferable that the diameter xa of the laser spot in region a is substantially the same as the diameter xb of the laser spot in region b. The diameters xa and xb of the laser spots are controlled by control units 38a and 38b, respectively.

[0045] It is preferable that the interval La1 between two laser spots Sa successively irradiated in region a and the interval Lb1 between two laser spots Sb successively irradiated in region b are substantially the same. For this reason, it is preferable that the frequency of the pulsed laser be smaller (the pulse period be longer) for laser irradiation device 35b, which is closer to center C, than for laser irradiation device 35a, which is farther from center C. The frequencies of the pulsed lasers of laser irradiation devices 35a and 35b are controlled by control units 38a and 38b, respectively.

[0046] In the region a, it is preferable that the interval La2 between two adjacent laser spots Sa in the moving direction of the laser irradiation device 35a and the interval Lb2 between two adjacent laser spots Sb in the moving direction of the laser irradiation device 35b are substantially the same. Therefore, it is preferable that the moving speeds of the laser irradiation devices 35a and 35b are substantially the same.

[0047] In this embodiment, it is more preferable that the intervals La1, Lb1 between two successively irradiated laser spots Sa, Sb and the intervals La2, Lb2 between two adjacent laser spots Sa, Sb in the movement direction of the laser irradiation devices 35a, 35b are substantially the same. In other words, it is more preferable that the intervals La1, Lb1, La2, Lb2 between the laser spots Sa, Sb are all equal.

[0048] By controlling the intervals La1, Lb1, La2, and Lb2 between the laser spots Sa and Sb and the diameters xa and xb of the laser spots within the above-mentioned ranges, it is possible to irradiate the laser more efficiently and uniformly onto multiple semiconductor memory devices (bonded substrates) 1, and to reduce the bonding strength of the laser absorption layer 14 and separate the substrate 10 from the semiconductor memory device (bonded substrate) 1. Therefore, the laser delamination method according to this embodiment can improve the manufacturing efficiency of the semiconductor memory device 2 and the reuse efficiency of the substrate 10.

[0049] In this embodiment, the rotation speed of the stage 32 of the laser processing apparatus 300A, the movement speed of the laser irradiation devices 35a and 35b, and the laser output (pulse laser frequency, laser spot diameter) of the laser irradiation devices 35a and 35b are respectively controlled by three control units 38a, 38b, and 39. However, without being limited to this, the rotation speed of the stage 32 of the laser processing apparatus 300A, the movement speed of the laser irradiation devices 35a and 35b, and the laser output (pulse laser frequency, laser spot diameter) of the laser irradiation devices 35a and 35b may be integrally controlled by a single control unit.

[0050] Also, the laser irradiation devices 35a and 35b are configured to move in different areas A and B. However, the present invention is not limited to this, and the laser irradiation devices 35a and 35b may both be configured to move in the same areas as in the first embodiment. In this case, the positions of the laser irradiation devices 35a and 35b may be shifted by L2 in the radial direction of the stage 32, and the movement speeds of the laser irradiation devices 35a and 35b may each be doubled. By configuring in this way, The laser irradiation trajectories of the laser irradiation devices 35a and 35b are such that one spiral is nested between the other spiral, and the two trajectories do not intersect, allowing the laser to be irradiated uniformly.

Claims

1. A stage that holds a plurality of bonded substrates, each having a first substrate and a second substrate, on a concentric circle and rotates around an axis at the center of the concentric circle; a laser irradiation device having a control unit that controls the output of an infrared pulse laser so that adjacent laser spots are spaced apart, and that is movable in a radial direction of the concentric circles; and The stage is provided with a holding mechanism capable of holding the second substrate peeled off from the plurality of bonded substrates on the stage.

2. 2. The laser processing apparatus according to claim 1, wherein the laser irradiation device is configured to be able to irradiate the plurality of laser spots along a spiral trajectory relative to the stage by rotating the plurality of substrates held on the concentric circles while the laser irradiation device is moving in the radial direction.

3. 3. The laser processing apparatus according to claim 2, wherein the control unit controls the laser processing apparatus so that x<L1 is satisfied when the diameter of the plurality of laser spots is x and the interval between the plurality of laser spots adjacent to each other in the rotation direction of the stage is L1.

4. 4. The laser processing device according to claim 3, wherein L1 is a linear velocity / frequency of the infrared pulse laser.

5. 4. The laser processing device according to claim 3, wherein the control unit controls the laser processing device so that x<L2 is satisfied, where x is a diameter of the laser spot and L2 is a distance between the plurality of laser spots adjacent to each other in the moving direction of the laser irradiation device.

6. The laser processing device according to claim 2 , wherein the control unit controls the diameter and frequency of the laser spot.

7. The laser processing device according to claim 2 , wherein the infrared pulse laser includes a carbon dioxide laser.

8. Further, the laser irradiation device has a plurality of laser irradiation devices, each of which moves in a radial direction of the concentric circles. The laser processing device according to claim 2.

9. 9. The laser processing apparatus according to claim 8, wherein each of the plurality of laser irradiation devices outputs an infrared pulse laser having a different frequency.

10. A plurality of bonded substrates, each having a first substrate and a second substrate bonded together via a laser absorbing layer, are arranged on a concentric circle of a stage; Rotating the stage around the center of the concentric circle as an axis; moving a laser irradiation device that irradiates the laser absorption layer with an infrared pulse laser in a radial direction of the concentric circles; the plurality of bonded substrates are closer to the outside of the stage than to the center of the stage; the closer the position of the laser irradiation device is to the center, the faster the rotation speed of the stage is increased or the frequency of the infrared pulse laser is reduced; When the rotation speed of the stage is increased, the movement speed of the laser irradiation device is increased. Laser peeling method.

11. 11. The laser peeling method according to claim 10, wherein the laser irradiation device is configured to be able to irradiate the infrared pulse laser along a spiral trajectory relative to the stage by rotating the plurality of bonded substrates arranged on the concentric circles while the laser irradiation device is moving in the radial direction.

12. The laser removal method according to claim 11 , wherein the laser irradiation device controls the output of the infrared pulse laser so that adjacent laser spots are spaced apart.

13. 13. The laser peeling method according to claim 12, wherein the laser irradiation device is controlled so that x<L1 is satisfied, where x is the diameter of the plurality of laser spots and L1 is the distance between the plurality of laser spots adjacent to each other in the rotation direction of the stage.

14. The laser delamination method according to claim 13, wherein L1 is the linear velocity / frequency of the infrared pulse laser.

15. 13. The laser peeling method according to claim 12, wherein the laser irradiation device is controlled so that x<L2 is satisfied, where x is the diameter of the plurality of laser spots and L2 is the distance between the plurality of laser spots adjacent to each other in the movement direction of the laser irradiation device.

16. The laser delamination method according to claim 11 , wherein the infrared pulsed laser comprises a carbon dioxide laser.

17. A plurality of bonded substrates, each having a first substrate and a second substrate bonded together via a laser absorbing layer, are arranged on a concentric circle of a stage; Rotating the stage around the center of the concentric circle as an axis; a laser irradiation device that irradiates the laser absorption layer with an infrared pulse laser is moved in a radial direction of the concentric circles; peeling off the second substrate; the laser absorption layer is provided between the first substrate and the second substrate and is closer to the second substrate than to the first substrate; the plurality of bonded substrates are closer to the outside of the stage than to the center of the stage; the closer the position of the laser irradiation device is to the center, the faster the rotation speed of the stage is increased or the frequency of the infrared pulse laser is reduced; In the case where the rotation speed of the stage is increased, the moving speed of the laser irradiation device is increased.

18. 18. The method for manufacturing a semiconductor device according to claim 17, wherein the laser irradiation device is configured to be able to irradiate the infrared pulse laser along a spiral trajectory relative to the stage by rotating the plurality of bonded substrates arranged on the concentric circles while the laser irradiation device is moving in the radial direction.

19. The method for manufacturing a semiconductor device according to claim 18 , wherein the laser absorption layer includes a silicon oxide film.

20. 19. The method for manufacturing a semiconductor device according to claim 18, 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 pulse laser is irradiated from the second substrate side.

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