Polishing apparatus, polishing method, and method for manufacturing semiconductor device

Abstract

The present invention provides a polishing apparatus, a polishing method, and a method for manufacturing a semiconductor device that improve the flatness of the substrate surface. [Solution] A polishing apparatus according to one embodiment includes a substrate holding unit for holding a substrate, a rotating platen for holding and rotating a polishing pad facing the substrate, a liquid supply unit for supplying liquid onto the polishing pad, and a control member provided between the rotating platen and the polishing pad, and at a position corresponding to the outer circumference of the polishing pad, and including a flexible member for controlling the deformation of the outer circumference of the polishing pad.

Description

Technical Field

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[0001] Embodiments of the present disclosure relate to a polishing apparatus, a polishing method, and a method of manufacturing a semiconductor device.

Background Art

[0002] A NAND-type flash memory is known as a semiconductor memory device. This NAND-type flash memory includes a memory cell array and its control circuit. As a method of manufacturing a semiconductor memory device, a method is known in which a memory cell array chip and a control circuit chip are formed on separate substrates and then bonded together. In this case, the bonding surfaces of the respective substrates need to be planarized.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Summary of the Invention

Problems to be Solved by the Invention

[0004] Embodiments according to the present disclosure provide a polishing apparatus, a polishing method, and a method of manufacturing a semiconductor device with improved flatness of the substrate surface.

Means for Solving the Problems

[0005] The polishing apparatus according to this embodiment includes a substrate holding unit for holding a substrate, a rotating platen for holding and rotating a polishing pad facing the substrate, a liquid supply unit for supplying liquid onto the polishing pad, and a control member provided between the rotating platen and the polishing pad, and at a position corresponding to the outer periphery of the polishing pad, and including a flexible member for controlling the deformation of the outer periphery of the polishing pad. [Brief explanation of the drawing]

[0006] [Figure 1] This figure shows the overall configuration of the semiconductor memory device (laminated substrate) according to this embodiment. [Figure 2A] This is a cross-sectional view showing the end of the semiconductor memory device (laminated substrate) according to this embodiment. [Figure 2B] This is a cross-sectional view showing the edges of a memory cell array substrate and a control circuit substrate according to one embodiment. [Figure 3] This is a cross-sectional view showing the configuration of a semiconductor memory device (laminated substrate) according to one embodiment. [Figure 4] This figure shows the overall configuration of a polishing apparatus according to one embodiment. [Figure 5] This is a cross-sectional view showing the configuration of a polishing apparatus according to one embodiment. [Figure 6] This is a top view showing the arrangement of a polishing pad deformation control member according to one embodiment. [Figure 7] This is an enlarged cross-sectional view showing the configuration of a polishing pad deformation control member according to one embodiment. [Figure 8] This is a top view showing the arrangement of an anti-ejection device according to one embodiment. [Figure 9] This is an enlarged top view showing the configuration of an anti-ejection device according to one embodiment. [Figure 10] This is a cross-sectional view showing the configuration of a vacuum chuck according to one embodiment. [Figure 11A] This is a top view showing an example of the arrangement of a residual film monitor sensor according to one embodiment. [Figure 11B] This is a top view showing an example of the arrangement of a residual film monitor sensor according to one embodiment. [Figure 12]It is a cross-sectional view showing the configuration of a polishing apparatus according to an embodiment. [Figure 13] An example of polishing a substrate according to an embodiment is shown. [Figure 14] It is a diagram for explaining a method of polishing a substrate according to an embodiment. [Figure 15] An example of polishing a substrate according to an embodiment is shown. [Figure 16] It is a diagram for explaining a method of polishing a substrate according to an embodiment. [Figure 17] It is a diagram for explaining a modified example of a method of polishing a substrate according to an embodiment. [Figure 18] It is a top view showing an example of the arrangement of pipes according to an embodiment. <000,0083>

Mode for Carrying Out the Invention

[0007] Hereinafter, the polishing apparatus, polishing method, and manufacturing method of a semiconductor device according to the present embodiment will be specifically described with reference to the drawings. In the following description, elements having substantially the same functions and configurations are denoted by the same reference numerals or reference numerals with an alphabet added after the same reference numeral, and will be described in duplicate only when necessary. Each of the embodiments shown below exemplifies an apparatus and a method for embodying the technical idea of this embodiment. One embodiment can be variously modified without departing from the gist of the invention. These embodiments and their modified examples are included in the invention described in the claims and the equivalent scope thereof.

[0008] For the sake of clearer explanation, the drawings may schematically represent the width, thickness, shape, etc. of each part compared to the actual aspect, but this is merely an example and does not limit the interpretation of the present invention. In this specification and each drawing, elements having the same functions as those described with respect to the already presented drawings may be denoted by the same reference numerals, and redundant explanations may be omitted in some cases.

[0009] In each embodiment, the direction from each substrate toward the memory cell or the control circuit may be referred to as upward. Conversely, the direction from the memory cell or the control circuit toward each substrate may be referred to as downward. Thus, for the sake of convenience of explanation, the terms upward or downward are used for explanation. However, for example, the vertical relationship between the substrate and the memory cell may be arranged in the reverse of the illustration. Also, in the following explanation, for example, the expression of a memory cell on a substrate merely explains the vertical relationship between the substrate and the memory cell as described above, and other members may be arranged between the substrate and the memory cell.

[0010] In this specification, expressions such as "α includes A, B, or C" do not exclude the case where α includes a plurality of combinations of A to C unless otherwise explicitly stated. Furthermore, these expressions do not exclude the case where α includes other elements.

[0011] The following embodiments can be combined with each other as long as no technical contradiction occurs.

[0012] [Semiconductor Memory Device (Bonded Substrate)] The configuration of the 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 1. FIG. 2A is a cross-sectional view showing an end portion of the semiconductor memory device 1. FIG. 2B is a cross-sectional view showing end portions of the memory cell array substrate and the control circuit substrate before bonding. FIG. 3 is a cross-sectional view showing a basic configuration of the semiconductor memory device 1.

[0013] As shown in Figure 1, the semiconductor memory device 1 comprises a memory cell array substrate 100 as a first circuit layer and a control circuit (CMOS circuit) substrate 200 as a second circuit layer. The memory cell array substrate 100 includes a substrate 10 and a memory cell array layer provided on the substrate 10. The control circuit substrate 200 includes a substrate 20 and a control circuit layer provided on the substrate 20. Details will be described later. The memory cell array substrate 100 and the control circuit substrate 200 are connected at a connection surface C1. For this reason, the bonding surfaces (connection surface C1) of the memory cell array substrate 100 and the control circuit substrate 200 are flattened. The first circuit layer and the second circuit layer are not particularly limited. For this reason, the semiconductor memory device of this embodiment may be referred to as a "semiconductor device".

[0014] To flatten the connection surfaces C1 of the memory cell array substrate 100 and the control circuit substrate 200, a polishing apparatus (Chemical Mechanical Polishing apparatus) described later is used. The polishing apparatus uses a chemical solution to polish and smooth the surface of the semiconductor device, thereby flattening one surface of the semiconductor device. The polishing apparatus is not limited to flattening the connection surfaces C1 of the memory cell array substrate 100 and the control circuit substrate 200, but can also be applied, for example, to flatten substrates 10 and 20, or to thin the semiconductor memory device 1.

[0015] The connection surfaces C1 of the memory cell array substrate 100 and the control circuit substrate 200 are preferably substantially parallel to the respective substrates 10 and 20. However, the connection surfaces C1 of the memory cell array substrate 100 and the control circuit substrate 200 may have lower flatness at the outer edges compared to the central part.

[0016] As shown in Figure 2A, for example, the outer edges of the connection surface C1 of the memory cell array substrate 100 and the control circuit substrate 200 may be over-polished (rolled off) compared to the central part. It is preferable that the roll-off amount z100 in the z-direction of the outer edge e1 of the memory cell array substrate 100 is small. It is also preferable that the roll-off amount z200 in the z-direction of the outer edge e1 of the control circuit substrate 200 is small. By having small roll-off amounts z100 of the memory cell array substrate 100 and z200 of the control circuit substrate 200, the radial unbonded width b of the semiconductor memory device 1 from the outer edge e1 of the connection surface C1 of the memory cell array substrate 100 and the control circuit substrate 200 to the bonding interface e2 can be suppressed.

[0017] As shown in Figure 2B, it is preferable that the radial roll-off width x100 of the semiconductor memory device 1 is small from the outer periphery e1 of the connection surface C100 of the memory cell array substrate 100 to the center side e100 of the roll-off region. It is also preferable that the radial roll-off width x200 of the semiconductor memory device 1 is small from the outer periphery e1 of the connection surface C200 of the control circuit substrate 200 to the center side e200 of the roll-off region. By having small roll-off widths x100 of the memory cell array substrate 100 and x200 of the control circuit substrate 200, the radial unbonded width b of the semiconductor memory device 1 from the outer periphery e1 of the connection surface C1 of the memory cell array substrate 100 and the control circuit substrate 200 to the bonding interface e2 can be suppressed.

[0018] It is preferable that the angle between the outer edge and the central part of the connection surface C100 of the memory cell array substrate 100, which connects the outer edge e1 of the connection surface C100 of the memory cell array substrate 100 to the roll-off width x100, is gentle. It is also preferable that the angle between the outer edge and the central part of the connection surface C200 of the control circuit substrate 200, which connects the outer edge e1 of the connection surface C200 of the control circuit substrate 200 to the roll-off width x200, is gentle. By making the angle between the outer edge and the central part of the connection surface C100 of the memory cell array substrate 100 and the angle between the outer edge and the central part of the connection surface C200 of the control circuit substrate 200 gentle, the radial unbonded width b of the semiconductor memory device 1 from the outer edge e1 of the connection surface C1 of the memory cell array substrate 100 and the control circuit substrate 200 to the bonding interface e2 can be suppressed.

[0019] Assuming the roll-off amount z100 of the memory cell array substrate 100 is the same, it is preferable that the radial roll-off width x100 of the semiconductor memory device 1 from the outer periphery e1 of the connection surface C100 is larger, and the angle between the outer edge and the central part of the connection surface C100 is gentler. Assuming the roll-off amount z200 of the control circuit substrate 200 is the same, it is preferable that the radial roll-off width x200 of the semiconductor memory device 1 from the outer periphery e1 of the connection surface C200 is larger, and the angle between the outer edge and the central part of the connection surface C200 is gentler. By making the angle between the outer edge and the central part of the connection surface C100 of the memory cell array substrate 100 and the angle between the outer edge and the central part of the connection surface C200 of the control circuit substrate 200 gentler, the radial unbonded width b of the semiconductor memory device 1 from the outer periphery e1 of the connection surface C1 of the memory cell array substrate 100 and the connection interface e2 can be suppressed. In this case, the radial unbonded width b of the semiconductor memory device 1 from the outer periphery e1 of the connection surface C1 between the memory cell array substrate 100 and the control circuit substrate 200 to the bonding interface e2 may be smaller than the roll-off width x100 of the memory cell array substrate 100 and the roll-off width x200 of the control circuit substrate 200.

[0020] As shown in Figure 2A, the central part of the semiconductor memory device 1 includes an effective element region R1 for manufacturing multiple semiconductor chips. The outer edge of the semiconductor memory device 1 includes an ineffective element region R2. The semiconductor memory device 1 includes the ineffective element region R2 around the effective element region R1. The effective element region R1 is located in the center of the semiconductor memory device 1 and has a shape close to a circle in plan view. The ineffective element region R2 is located at the outer edge of the semiconductor memory device 1 and has a shape close to a ring in plan view. The ineffective element region R2 encloses the effective element region R1 in a ring shape in plan view.

[0021] The active element region R1 includes the memory cell array and control circuit. On the other hand, the inactive element region R2 does not necessarily have to include the memory cell array or CMOS circuit. Even if there are wirings etc. in the inactive element region R2, they are not electrically connected and do not constitute a chip. The unbonded width x is located within the inactive element region R2. By suppressing the unbonded width x, the semiconductor memory device 1 can make the active element region R1 larger and manufacture more semiconductor chips.

[0022] [Structure of the control circuit board] As shown in Figure 3, the control circuit board 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 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 substrate 100 are arranged on the connection surface C1 of the circuit-side wiring layer 27 opposite to the substrate 20. The substrate 20 may be a semiconductor substrate such as a silicon wafer.

[0023] [Structure of memory cell array substrate] As shown in Figure 3, the memory cell array substrate 100 includes a substrate 10, a plurality of electrode layers 16, a plurality of semiconductor pillars 15, and a memory-side wiring layer 17. The plurality of electrode layers 16 are alternately stacked one layer at a time with a plurality of insulating layers on the substrate 10. Each semiconductor pillar 15 is positioned perpendicular to the substrate 10 and penetrates the stacked plurality of electrode layers 16. Each semiconductor pillar 15 functions as a plurality of transistors, including memory cells, by being combined with the plurality of electrode layers 16 via the insulating layer. That is, in the memory cell array region 11 (upper right portion of Figure 3), a plurality of transistors, including memory cells, are arranged in three dimensions. The semiconductor pillar 15 is electrically connected to a source line at one end (substrate 10 side) and electrically connected to the memory-side wiring layer 17 at the other end (opposite side of the substrate 10). Connection terminals for connection to the control circuit substrate 200 are arranged on the connection surface C1 of the memory-side wiring layer 17 opposite to the substrate 10. The substrate 10 may be a semiconductor substrate such as a silicon wafer.

[0024] On the substrate 10, a contact area 12 (upper left portion in Figure 3) is arranged alongside the memory cell array area 11. In the contact area 12, multiple electrode layers 16 each have terminal portions extended in a stepped manner. Each terminal portion is connected to vertically arranged wiring via contact holes opened in the insulating film. These vertical wirings are electrically connected to the memory-side wiring layer 17 and connected to the control circuit board 200 via connection terminals.

[0025] [Polishing equipment] The polishing apparatus 300 according to this embodiment will be described with reference to Figures 4 to 12.

[0026] Figure 4 is a diagram showing the overall configuration of the polishing apparatus 300. Figure 5 is a cross-sectional view showing the configuration of the polishing apparatus 300. The polishing apparatus 300 comprises a substrate holding section 400, a rotating platen 500, a polishing pad deformation control member 600, and a polishing pad 700.

[0027] The substrate holding portion 400 has a shape close to a circle in plan view and holds a wafer-shaped (disk-shaped) substrate W. The substrate W is positioned so that its center coincides with the center of the substrate holding portion 400. The substrate holding portion 400 includes a membrane 410 and a control unit 430. The substrate W is held by the substrate holding portion 400 via the membrane 410. The membrane 410 has a shape close to a circle in plan view and is a flexible airbag made of rubber or synthetic resin. The substrate holding portion 400 creates a near-vacuum between the membrane 410 and the substrate W by bringing the membrane 410 and the substrate W into close contact, and uses the pressure difference to adhere the entire surface to the substrate W. The substrate W may be a memory cell array substrate 100 or a control circuit substrate 200, a substrate 10 or a substrate 20, or a semiconductor memory device 1. The substrate holding portion 400 holds the substrate W so that the polishing surface of the substrate W faces the polishing pad 700.

[0028] The membrane 410 can press the substrate W against the polishing pad 700 during polishing by controlling the air pressure inside the airbag. The membrane 410 may have multiple concentric compartments around an axis C2 that includes the center of the substrate holding portion 400, and the air pressure may be controlled by these multiple compartments. The air pressure of the membrane 410 may be controlled by the control unit 430.

[0029] The substrate holder 400 is equipped with a lifting mechanism that raises and lowers the substrate W in the vertical direction (Z direction) relative to the polishing pad 700. The lifting and lowering operation of the lifting mechanism allows the substrate W to be pressed against the polishing pad 700 during polishing, and also allows the substrate W to be attached to and detached from the membrane 410 of the substrate holder 400 before and after polishing.

[0030] The substrate holder 400 may be equipped with a rotation mechanism 420. The substrate holder 400 may rotate by the rotation mechanism 420 around a vertical axis C2 that includes the center of the substrate holder 400. As the substrate holder 400 rotates, the substrate W held by the substrate holder 400 may rotate around the axis C2 that includes the center of the substrate W. The rotational movement, direction of rotation, and rotational speed of the substrate holder 400 driven by the rotation mechanism 420 may be controlled by the control unit 430. However, it is not limited to this, and for example, if the rotary platen 500 rotates, the substrate holder 400 does not need to rotate.

[0031] A height sensor 800 may be placed below the substrate holder 400. The height sensor 800 may detect the position of the substrate holder 400 relative to the rotary platen 500.

[0032] Below the substrate holder 400, a rotary platen 500 is positioned such that its center coincides with the center of the substrate holder 400. The rotary platen 500 has a shape close to a circle in plan view and holds a disc-shaped polishing pad 700. The polishing pad 700 is positioned such that its center coincides with the center of the rotary platen 500. The diameter of the polishing pad 700 may be larger than the diameter of the substrate W, and the diameter of the polishing pad 700 may be smaller than the diameter of the substrate holder 400.

[0033] The rotary platen 500 is equipped with a polishing pad deformation control member 600. Figure 6 is a top view showing the arrangement of the polishing pad deformation control member 600. Figure 7 is an enlarged cross-sectional view showing the configuration of the polishing pad deformation control member 600. The polishing pad deformation control member 600 controls the deformation of the polishing pad 700 during polishing, as will be described later.

[0034] As shown in Figures 6 and 7, the polishing pad deformation control member 600 is annular in shape and is positioned concentrically around axis C2 with respect to the circular rotating platen 500 in a plan view, below the outer peripheral end of the polishing pad 700. The polishing pad deformation control member 600 is positioned below the outer peripheral end of the substrate W (i.e., on the rotating platen 500 side) via the polishing pad 700. The polishing pad deformation control member 600 includes a contact member 610 for contact with the polishing pad 700. The contact member 610 is made of flexible rubber such as silicone rubber or resin, and the contact member 610 of the polishing pad deformation control member 600 and the polishing pad 700 may be fixed together with adhesive tape. The contact member 610 is annular in shape and is provided on the outer peripheral part of the circular rotating platen 500 in a plan view, concentrically around axis C2, and positioned between the rotating platen 500 and the polishing pad 700. In other words, the contact member 610 is provided at a position corresponding to the outer peripheral part of the polishing pad 700.

[0035] The polishing pad deformation control member 600 controls the pressure of the internal air leading to the contact member 610, thereby pressing the polishing pad 700 against the substrate W or pulling it away from the substrate W during polishing (applying pressure). The polishing pad deformation control member 600 is connected to a pipe 570 provided in the rotary platen 500 and has a plurality of concentrically partitioned openings 630 that are exposed to the contact member 610, and is configured to control the air pressure through the plurality of openings 630. The pipe 570 is connected to, for example, a pump, and each of the plurality of openings 630 is configured to apply suction (applying pressure) or pressurization to the contact member 610. However, it is not limited to this, and the polishing pad deformation control member 600 may also include a lifting mechanism 620 that raises and lowers the polishing pad 700 in the vertical direction (Z direction). The lifting and lowering operation of the lifting mechanism 620 can press the polishing pad 700 against the substrate W or pull it away from the substrate W during polishing. As will be described later, the polishing pad deformation control member 600 may have a plurality of openings 630 arranged concentrically around an axis C2 that includes the center of the rotary platen 500, and the pressing or pulling pressure may be controlled by the plurality of openings 630.

[0036] The rotary platen 500 comprises a rotation mechanism 520 and a control unit 530. The rotary platen 500 rotates around an axis C2 containing the center of the rotary platen 500 by the rotation mechanism 520. As the rotary platen 500 rotates, the polishing pad 700 held by the rotary platen 500 also rotates around an axis C2 containing the center of the polishing pad 700. The rotational operation, direction of rotation, and rotational speed of the rotary platen 500 driven by the rotation mechanism 520 may be controlled by the control unit 530. However, it is not limited to this, and the rotary platen 500 does not need to rotate when the substrate holding part 400 rotates.

[0037] The rotary platen 500 includes a liquid supply unit (not shown) and piping 540 for supplying liquid. The liquid supply unit stores water or chemical solution and supplies it to the polishing surface of the substrate W through piping 540 (here, when water or chemical solution is not distinguished, it is referred to as liquid). The liquid supply unit is connected to piping 540 and supplies liquid to piping 540 while adjusting the flow rate and concentration of the liquid. Piping 540 passes through the polishing pad 700 and supplies liquid to the surface of the polishing pad 700 (on the substrate W side).

[0038] Multiple pipes 540 may be arranged. Multiple pipes 540 may be arranged concentrically on a circle around axis C2. In this case, the flow rate and concentration of the liquid may be controlled collectively by multiple pipes 540 arranged on a single circumference.

[0039] The rotary table 500 may also be equipped with an anti-ejection device 550. Figure 8 is a top view showing the arrangement of the anti-ejection device 550. Figure 9 is an enlarged top view showing the configuration of the anti-ejection device 550.

[0040] The anti-ejection device 550 may penetrate the polishing pad 700 and protrude from the surface of the polishing pad 700 (on the substrate W side). As shown in Figure 8, multiple anti-ejection devices 550 may be arranged. The anti-ejection devices 550 may be arranged as points on a concentric circle around axis C2. Preferably, three or more anti-ejection devices 550 are arranged on a concentric circle around axis C2. The anti-ejection devices 550 are arranged on a circumference that is larger than the substrate W and smaller than the polishing pad 700. The anti-ejection devices 550 are arranged at the outer peripheral end of the polishing pad 700 on which the polishing pad deformation control member 600 is placed.

[0041] As shown in Figure 9, the anti-ejection device 550 may be, for example, an elliptical pin. The anti-ejection device 550 may be rotatable and vertically movable within the through-hole of the polishing pad 700. Before and after polishing, the anti-ejection device 550 may be housed within the through-hole of the polishing pad 700 so that its minor axis matches the diameter of the polishing pad 700. During polishing, the anti-ejection device 550 may be able to protrude from the through-hole of the polishing pad 700 so that its major axis matches the diameter of the polishing pad 700. With this configuration, the anti-ejection device 550 can more precisely correct the position of the substrate W on the rotating platen 500.

[0042] However, the substrate holding portion 400 may also include a vacuum chuck 440. Figure 10 is a cross-sectional view showing the configuration of the vacuum chuck 440. As shown in Figure 10, the substrate holding portion 400 may hold the substrate W by a vacuum chuck 440 that penetrates the membrane 410. The vacuum chuck 440 may be arranged in multiple compartments, and the air suction pressure may be controlled by the multiple compartments. If the vacuum chuck 440 holds the central part of the substrate W on the back surface while polishing, the anti-ejection device 550 may not be necessary.

[0043] The rotary platen 500 may further include a residual film monitor sensor 560. Figures 11A and 11B are top views showing an example of the arrangement of the residual film monitor sensor 560.

[0044] The residual film monitor sensor 560 penetrates the polishing pad 700 and is exposed on the surface of the polishing pad 700 (the substrate W side). The residual film monitor sensor 560 is, for example, an optical sensor that measures the film thickness on the surface of the substrate W without contact. As shown in Figure 11A, multiple residual film monitor sensors 560 may be arranged at the outer edge of the polishing pad 700. The residual film monitor sensors 560 may also be arranged one by one on multiple concentric circles around axis C2. The residual film monitor sensor 560 detects the thickness at each outer edge position of the substrate W. By detecting the thickness at each outer edge position of the substrate W, the deformation of the polishing pad 700 can be controlled more precisely in accordance with the amount of polishing of the substrate W. As shown in Figure 11A, multiple residual film monitor sensors 560 may be arranged together in one place. However, it is not limited to this, and as shown in Figure 11B, multiple residual film monitor sensors 560 may be distributed and arranged at multiple locations.

[0045] Figure 12 is a cross-sectional view showing the configuration of the polishing apparatus 300a. In this embodiment, the polishing apparatus 300 has been described as a face-down type in which the substrate holder 400 is placed on the rotating platen 500 and the polishing surface of the substrate W is positioned facing downwards. However, it is not limited to this, and as shown in Figure 12, the polishing apparatus 300a may also be a face-up type in which the rotating platen 500 is placed on the substrate holder 400 and the polishing surface of the substrate W is positioned facing upwards.

[0046] [Polishing method A] A method for polishing a substrate W will be described using the polishing apparatus 300 according to this embodiment. The semiconductor memory device (bonded substrate) 1 of this embodiment is manufactured by bonding a memory cell array substrate 100 and a control circuit substrate 200, which have been polished using the polishing method described below. Figure 13 shows an example of substrate polishing A. Figure 14 is a diagram illustrating the substrate polishing method A.

[0047] As shown in Figure 13, if the area around the outer periphery e1 of the substrate Wa is over-polished (referred to as an over-polished outer periphery shape), the polishing method A according to this embodiment is preferable in which the roll-off amount za at the outer periphery e1 of the substrate Wa is not changed, the radial roll-off width xa from the outer periphery e1 of the substrate Wa is made larger, and the angle θ between the outer edge and the central part of the connecting surface C100 is polished more smoothly.

[0048] Figure 14 shows the polishing apparatus 300 and substrate Wa during the polishing process in polishing method A in the lower panel, and the pressure P at substrate Wa corresponding to the horizontal position of substrate Wa shown in the lower panel in the upper panel. The white arrows in Figure 14 indicate the magnitude and direction of the respective air pressures. The arrows shown within the polishing pad 700 indicate the direction of the pressure.

[0049] As shown in Figure 14, when the substrate Wa has an over-outer-peripheral shape, the polishing method A according to this embodiment preferably controls the air pressure of the multiple openings 630 of the polishing pad deformation control member 600. The multiple openings 630 include, for example, an opening 630a located on the outer periphery, an opening 630c located on the central side, and an opening 630b located between openings 630a and 630c. That is, when the polishing pad deformation control member 600 has three concentric openings: an opening 630a below the non-contact area between the substrate Wa and the polishing pad 700, an opening 630b below the area including the vicinity of the outer periphery e1 of the substrate Wa, and an opening 630c below the contact area between the substrate Wa and the polishing pad 700, the air pressure in opening 630c is made greater than the air pressure in openings 630a and 630b, pressing the polishing pad 700 on opening 630c against the substrate W. At this time, the air pressure in the openings 630a, 630b, and 630c is, for example, pressurized. The lifting mechanism 620 lowers the polishing pad 700 during polishing in a direction that pulls it away from the substrate W in response to the pressure in the opening 630c.

[0050] In the example shown in Figure 14, the pressure applied to the substrate Wa is increased by pressure P1 through the membrane 410 across the entire contact area between the substrate W and the polishing pad 700. At the opening 630c, pressure P2 is further increased by the polishing pad deformation control member 600. At openings 630a and 630b, the air pressure is low, and the lifting mechanism 620 descends in a direction that pulls the polishing pad 700 away from the substrate W, causing the pressure P3 applied to the substrate Wa to decrease sharply towards the non-contact area between the substrate W and the polishing pad 700. As a result, the polishing method A according to this embodiment can polish the substrate Wa with a larger radial roll-off width xa from the outer periphery e1 and a smoother angle θ between the outer edge and the central part of the connection surface C100, without changing the roll-off amount za of the substrate Wa.

[0051] [Polishing method B] A method B for polishing a substrate W will be described using the polishing apparatus 300 according to this embodiment. Figure 15 shows an example B of polishing a substrate W. Figure 16 is a diagram illustrating the substrate polishing method B.

[0052] As shown in Figure 15, if the substrate Wb has an over-polished shape near the center (referred to as an under-polished shape on the outer periphery), the polishing method B according to this embodiment preferably polishes only the residual film zb on the outer periphery e1 of the substrate Wb.

[0053] Figure 16 shows the polishing apparatus 300 and substrate Wb during the polishing process in polishing method B in the lower panel, and the pressure P at the substrate Wb corresponding to the horizontal position of the substrate Wb shown in the lower panel in the upper panel. The white arrows in Figure 16 indicate the magnitude and direction of the respective air pressures. The arrows shown within the polishing pad 700 indicate the direction of the pressure.

[0054] As shown in Figure 16, when the substrate Wb has an under-outer peripheral shape, the polishing method B according to this embodiment preferably controls the air pressure in the multiple openings 630 of the polishing pad deformation control member 600. If the polishing pad deformation control member 600 has three concentric openings: an opening 630a below the non-contact area between the substrate Wb and the polishing pad 700, an opening 630b below the area including the vicinity of the outer peripheral e1 of the substrate Wb, and an opening 630c below the contact area between the substrate Wb and the polishing pad 700, the air pressure in opening 630c may be made lower than the air pressure in openings 630a and 630b to prevent the polishing pad 700 on opening 630c from being pressed too hard against the substrate W. Details will be described later. For example, the air pressure in openings 630b and 630a is negative pressure, and the air pressure in opening 630c is positive pressure. The air pressure at opening 630c may be less than the air pressure at opening 630a, and the air pressure at opening 630c may be less than the air pressure at opening 630a.

[0055] In the example shown in Figure 16, the pressure applied to the substrate Wb is a pressure P1 mediated by the membrane 410, which is applied across the entire contact area between the substrate W and the polishing pad 700. Since the substrate Wb, which has an under-circumferential shape, has a convex residual film zb near the outer circumference e1, it is preferable to adjust the pressure so that excessive pressure is not applied to the substrate Wb at the contact point between the polishing pad 700 and the substrate Wb. For example, by creating a negative pressure at openings 630a and 630b, a relaxed pressure P4 is applied to the substrate Wb. At this time, the air pressure at opening 630c is less than the air pressure at openings 630a and 630b. The air pressure at opening 630c is pressurized. Also, if openings 630a and 630b are created with a negative pressure, the substrate Wb and the polishing pad 700 may not make proper contact. Therefore, the lifting mechanism 620 may be raised to allow the substrate Wb and the polishing pad 700 to make proper contact. Furthermore, in the region outside the outer periphery e1 of the substrate Wb, the substrate Wb and the polishing pad 700 are not in contact, so the pressure P5 applied to the substrate Wb becomes zero. As a result, the polishing method B according to this embodiment can polish only the residual film zb on the outer periphery e1 of the substrate Wb.

[0056] [Example 1] In polishing methods A and B according to this embodiment, the pressure applied to the substrate W is controlled by controlling the deformation of the polishing pad 700 with the polishing pad deformation control member 600 of the polishing apparatus 300. However, the polishing method according to this modified example may further control the pressure applied to the substrate W by controlling the air pressure of the membrane 410. Figure 17 is a diagram illustrating a modified example of the substrate polishing method.

[0057] As shown in Figure 17, a modified version of the polishing method according to this embodiment is preferable to control the air pressure in multiple compartments of the membrane 410. If the membrane 410 has three concentric compartments, compartment 410a, compartment 410b, and compartment 410c, extending from the outer circumference of the substrate W towards the center, the air pressure in compartments 410a and 410b may be made greater than the air pressure in compartment 410c, thereby pressing the substrate W on compartments 410a and 410b against the polishing pad 700. In this modified polishing method, by controlling the air pressure of the membrane 410, the adjustment range may be controlled by area interference to an extent that cannot be addressed solely by controlling the deformation of the polishing pad 700 with the polishing pad deformation control member 600.

[0058] [Differentiation 2] In polishing methods A and B according to this embodiment, the pressure applied to the substrate W was controlled by controlling the deformation of the polishing pad 700 with the polishing pad deformation control member 600 of the polishing device 300. However, the polishing method according to this modified example may further control the amount of polishing of the substrate W by adjusting the flow rate and concentration of the liquid supplied to the surface of the polishing pad 700. Figure 18 is a diagram illustrating the arrangement of the piping 540.

[0059] As shown in Figure 18, a modified version of the polishing method according to this embodiment is preferably one in which the flow rate and concentration of the liquid supplied to the surface of the polishing pad 700 are adjusted. When the multiple pipes 540 are arranged on three concentric circles, pipe 540a, pipe 540b, and pipe 540c, from the outer circumference of the substrate W toward the center, the flow rate of the liquid supplied from pipe 540a to the surface of the polishing pad 700 may be greater than the flow rate of the liquid supplied from pipe 540b to the surface of the polishing pad 700, and the flow rate of the liquid supplied from pipe 540b to the surface of the polishing pad 700 may be greater than the flow rate of the liquid supplied from pipe 540c to the surface of the polishing pad 700. The concentration of the liquid supplied from pipe 540a to the surface of the polishing pad 700 may be greater than the concentration of the liquid supplied from pipe 540b to the surface of the polishing pad 700, and the concentration of the liquid supplied from pipe 540b to the surface of the polishing pad 700 may be greater than the concentration of the liquid supplied from pipe 540c to the surface of the polishing pad 700. However, the method is not limited to this, and the concentration and flow rate of the liquid can be adjusted as appropriate by the chemical solution. Also, the liquid supplied from the pipe 540c to the surface of the polishing pad 700 may be, for example, water. In this modified polishing method, the amount of polishing of the substrate W may be controlled by adjusting the flow rate and concentration of the liquid supplied to the surface of the polishing pad 700.

[0060] In the polishing method according to this embodiment, by controlling the deformation of the polishing pad 700 with the polishing pad deformation control member 600, the radial roll-off width x from the outer periphery e1 of the substrate W can be increased without changing the roll-off amount z of the substrate W, and the angle θ between the outer edge and the central part of the connection surface C100 can be polished more smoothly, thereby improving the flatness of the substrate W surface. By improving the flatness of the substrate W surface, for example, the unbonded width b of the semiconductor memory device (bonded substrate) 1 can be suppressed. By suppressing the unbonded width b, the effective element area R1 of the semiconductor memory device 1 can be increased, and more semiconductor chips can be manufactured. [Explanation of symbols]

[0061] 1 Semiconductor memory device, 10 Substrate, 20 Substrate, 100 Memory cell array substrate, 200 Control circuit board, 300 Polishing device, 400 Substrate holder, 410 Membrane, 420 Rotation mechanism, 430 Control unit, 440 Vacuum chuck, 500 Rotating platen, 520 Rotation mechanism, 530 Control unit, 540 Piping, 550 Prevention device, 560 Residual film monitor sensor, 570 Piping, 600 Polishing pad deformation control member, 610 Contact member, 620 Lifting mechanism, 630 Opening, 700 Polishing pad, 800 Sensor

Claims

1. A substrate holding section that holds the substrate, A rotating platen that holds a polishing pad facing the substrate and rotates, A liquid supply unit that supplies liquid onto the polishing pad, A polishing apparatus comprising a control member that includes a flexible member and is provided between the rotating platen and the polishing pad, and at a position corresponding to the outer circumference of the polishing pad, for controlling the deformation of the outer circumference of the polishing pad.

2. The polishing apparatus according to claim 1, wherein the control member is configured to apply pressure to the outer periphery of the polishing pad toward the side opposite to the substrate.

3. The polishing apparatus according to claim 1, wherein the control member applies pressure to the outer periphery of the polishing pad toward the substrate.

4. The polishing apparatus according to claim 1, wherein the center of the substrate and the center of the rotating platen overlap.

5. The polishing apparatus according to claim 1, wherein the diameter of the polishing pad is larger than the diameter of the substrate.

6. The liquid supply unit includes piping that penetrates the polishing pad, The polishing apparatus according to claim 1, wherein liquid is supplied to the substrate side of the polishing pad through the aforementioned piping.

7. The polishing apparatus according to claim 1, further comprising an optical sensor for measuring the film thickness on the surface of the substrate.

8. The substrate held in the substrate holder is brought into contact with a polishing pad held in a rotating platen that rotates opposite to the substrate. A polishing method comprising polishing the surface of the substrate while controlling the deformation of the outer periphery of the polishing pad.

9. The polishing method according to claim 8, wherein the outer periphery of the polishing pad is deformed toward the opposite side from the substrate.

10. The polishing method according to claim 8, wherein the outer periphery of the polishing pad is deformed toward the substrate.

11. The polishing method according to claim 8, wherein the center of the substrate and the center of rotation of the rotary platen coincide.

12. The polishing method according to claim 8, further comprising supplying liquid to the substrate through a pipe that penetrates the polishing pad.

13. The polishing method according to claim 8, wherein the deformation of the outer periphery of the polishing pad is performed by controlling a flexible member provided between the rotating platen and the polishing pad, and at a position corresponding to the outer periphery of the polishing pad.

14. The semiconductor substrate held in the substrate holder is brought into contact with a polishing pad held in a rotating platen that rotates opposite to the semiconductor substrate. A method for manufacturing a semiconductor device, comprising polishing the surface of a semiconductor substrate while controlling the deformation of the outer circumference of the polishing pad.

15. The method for manufacturing a semiconductor device according to claim 14, wherein the deformation of the outer periphery of the polishing pad is performed by controlling a flexible member provided between the rotating platen and the polishing pad, and at a position corresponding to the outer periphery of the polishing pad.

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