POLISHING APPARATUS, POLISHING METHOD, AND MANUFACTURING METHOD OF SEMICONDUCTOR DEVICE

Description

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2024-221776, filed on December 18, 2024, the entire contents of which are incorporated herein by reference.

FIELD

Embodiment described herein relate generally to a polishing apparatus, a polishing method, and a manufacturing method of a semiconductor device.

BACKGROUND

A NAND flash memory is known as a semiconductor memory device. The NAND flash memory includes a memory cell array and its control circuit. A method in which a memory cell array chip and a control circuit chip are formed on separate substrates and later bonded together is known as a method of manufacturing the semiconductor memory device. In this case, the bonded surfaces of the respective substrates need to be planarized.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram showing the overall configuration of a semiconductor memory device (bonded substrate) according to the present embodiment.

FIG. 2A is a cross-sectional view showing an edge portion of a semiconductor memory device (bonded substrate) according to the present embodiment.

FIG. 2B is a cross-sectional view showing edge portions of a memory cell array substrate and a control circuit substrate according to an embodiment.

FIG. 3 is a cross-sectional view showing a configuration of a semiconductor device (bonded substrate) according to an embodiment.

FIG. 4 is a diagram showing an entire configuration of a polishing apparatus according to an embodiment.

FIG. 5 is a diagram showing a cross-sectional view showing a configuration of a polishing apparatus according to an embodiment.

FIG. 6 is a top view showing an arrangement of a polishing pad deformation controller according to an embodiment.

FIG. 7 is an enlarged cross-sectional view showing a configuration of a polishing pad deformation controller according to an embodiment.

FIG. 8 is a top view showing an arrangement of a slip out prevention device according to an embodiment.

FIG. 9 is an enlarged cross-sectional view showing a configuration of a slip out prevention device according to an embodiment.

FIG. 10 is a cross-sectional view showing a configuration of a vacuum chuck according to an embodiment.

FIG. 11A is a top view showing an example of an arrangement of a monitor sensor according to an embodiment.

FIG. 11B is a top view showing an example of an arrangement of a monitor sensor according to an embodiment.

FIG. 12 is a cross-sectional view showing a configuration of a polishing apparatus according to an embodiment.

FIG. 13 shows a polishing example of a substrate according to an embodiment.

FIG. 14 is a diagram showing a polishing method of a substrate according to an embodiment.

FIG. 15 shows a polishing example of a substrate according to an embodiment.

FIG. 16 is a diagram showing a polishing method of a substrate according to an embodiment.

FIG. 17 is a diagram showing a modification of a polishing apparatus and a polishing method of a substrate according to an embodiment.

FIG. 18 is a top view showing an example of an arrangement of a pipe outlet according to an embodiment.

DETAILED DESCRIPTION

Hereinafter, a polishing apparatus, a polishing method, and a method of manufacturing a semiconductor device according to the present embodiment will be described in detail with reference to the drawings. In the following description, elements having substantially the same functions and configurations are denoted by the same reference signs or the same reference signs with letters, and duplicate descriptions will be provided only when necessary. Each of the embodiments described below exemplifies a device and a method for embodying a technical idea of the present embodiment. Various modifications may be made to an embodiment without departing from the spirit of the disclosure. These embodiments and modifications thereof are included in the scope of the disclosure described in the claims and equivalents thereof.

In the drawings, the widths, thicknesses, shapes, and the like of the respective portions may be schematically represented in comparison with the actual embodiments for clarity of explanation, but the drawings are merely examples, and do not limit the interpretation of the present disclosure. In the present specification and the drawings, elements having the same functions as those described with respect to the above-described drawings are denoted by the same reference signs, and duplicate descriptions thereof may be omitted.

In the respective embodiments, a direction from each substrate to a memory cell or control circuit may be referred to as “above”. Conversely, a direction from the memory cell or control circuit to each substrate may be referred to as “below”. As described above, for convenience of explanation, the term “above” or “below” is used to describe the configuration, but the vertical relationship between the substrate and the memory cell may be reversed from that shown in the figure. Further, in the following explanation, for example, the expression “a memory cell on a substrate” merely describes 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.

In the present specification, the expressions “α includes A, B, or C” does not exclude the case where α includes a plurality of combinations of A to C unless otherwise specified. Furthermore, these expressions do not exclude the case where α includes other elements.

The following embodiments can be combined with each other as long as there is no technical contradiction.

A polishing apparatus according to an embodiment includes a polishing head holding a substrate, a rotating platen rotating and holding a polishing pad facing the substrate, a liquid supplier supplying liquid onto the polishing pad, and a deformation part provided between the rotating platen and the polishing pad and at a position corresponding to the outer periphery of the polishing pad, the deformation part including a flexible member configured to control the deformation of the outer periphery of the polishing pad.

Semiconductor Memory Device (Bonded Substrate)

A configuration of a semiconductor memory device (bonded substrate) 1 according to the present embodiment will be described with reference to FIG. 1 to FIG. 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 edge portion (outer periphery) of the semiconductor memory device 1. FIG. 2B is a cross-sectional view showing edge portions of a memory cell array substrate and a control circuit substrate before bonding. FIG. 3 is a cross-sectional view showing a basic configuration of the semiconductor memory device 1.

As shown in FIG. 1, the semiconductor memory device 1 includes 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 thereof will be described later. The memory cell array substrate 100 and the control circuit substrate 200 are connected at a connection surface C1. Therefore, the bonded surface (connection surface C1) of the memory cell array substrate 100 and control circuit substrate 200 are planarized. In addition, the first circuit layer and the second circuit layer are not particularly limited. Therefore, the semiconductor memory device of the embodiment may be referred to as a “semiconductor device”.

A polishing apparatus (Chemical Mechanical Polishing apparatus) to be described later is used for planarizing the connection surface C1 of each of the memory cell array substrate 100 and the control circuit substrate 200. The polishing apparatus uses a chemical solution to polish and smooth the surface of the semiconductor device, thereby planarizing one surface of the semiconductor device. The polishing apparatus is not limited to the planarizing of the connection surface C1 of the memory cell array substrate 100 and the control circuit substrate 200, and can be applied to, for example, the planarizing of the substrates 10 and 20 or the thinning of the semiconductor memory device 1.

The connection surface C1 of each of the memory cell array 100 and the control circuit substrate 200 is preferably substantially parallel to the respective substrates 10 and 20. However, the connection surface C1 of each of the memory cell array substrate 100 and the control circuit substrate 200 may have a lower degree of planarity at the outer edge portion compared with the central portion.

As shown in FIG. 2A, for example, the outer edge portion may be over-polished (edge rolled off) as compared with the central portion of the connection surface C1 of each of the memory cell array substrate 100 and the control circuit substrate 200. The roll-off amount z100 in a direction z of an outer periphery e1 of the memory cell array substrate 100 is preferably small. A roll-off amount z200 in the direction z of the outer periphery e1 of the control circuit substrate 200 is preferably small. Since the roll-off amount z100 of the memory cell array substrate 100 and the roll-off amount z200 of the control circuit substrate 200 are small, it is possible to suppress an unbonded width b in the radial direction of the semiconductor memory device 1 from the outer periphery e1 to a bonding interface e2 of the connection surface C1 of the memory cell array substrate 100 and the control circuit substrate 200.

As shown in FIG. 2B, a roll-off width x100 in the radial direction of the semiconductor memory device 1 from the outer periphery e1 to the center side e100 of the roll-off region of a connection surface C100 of the memory cell array substrate 100 is preferably small. A roll-off width x200 in the radial direction of the semiconductor memory device 1 from the outer periphery e1 to the center side e200 of the roll-off region of a connection surface C200 of the control circuit substrate 200 is preferably small. Since the roll-off width x100 of the memory cell array substrate 100 and the roll-off width x200 of the control circuit substrate 200 are small, the unbonded width b in the radial direction of the semiconductor memory device 1 from the outer periphery e1 to the bonding interface e2 of the connection surface C1 of the memory cell array substrate 100 and the control circuit substrate 200 can be suppressed.

An angle formed by the outer edge portion and the central portion of the connection surface C100 connecting from the outer periphery e1 to the roll-off width x100 of the connection surface C100 of the memory cell array substrate 100 is preferably gentle. An angle formed by the outer edge portion and the central portion of the connection surface C200 connecting from the outer periphery e1 to the roll-off width x200 of the connection surface C200 of the control circuit substrate 200 is preferably gentle. Since the angle formed by the outer edge portion and the central portion of the connection surface C100 of the memory cell array substrate 100 and the angle formed by the outer edge portion and the central portion of the connection surface C200 of the control circuit substrate 200 are gentle, the unbonded width b in the radial direction of the semiconductor memory device 1 from the outer periphery e1 to the bonding interface e2 of the connection surface C1 of the memory cell array substrate 100 and the control circuit substrate 200 can be suppressed.

When it is assumed that the roll-off amount z100 of the memory cell array substrate 100 is the same, the roll-off width x100 in the radial direction of the semiconductor memory device 1 from the outer periphery e1 of the connection surface C100 is preferably larger, and the angle formed by the outer edge portion and the central portion of the connection surface C100 is preferably gentle. When it is assumed that the roll-off amount z200 of control circuit substrate 200 is the same, the roll-off width x200 in the radial direction of the semiconductor memory device 1 from the outer periphery e1 of the connection surface C200 is preferably larger, and the angle formed by the outer edge portion and the central portion of the connection surface C200 is preferably gentle. Since the angle formed by the outer edge portion and the central portion of the connection surface C100 of the memory cell array substrate 100 and the angle formed by the outer edge portion and the central portion of the connection surface C200 of the control circuit substrate 200 are gentle, the unbonded width b in the radial direction of the semiconductor memory device 1 from the outer periphery e1 to the bonding interface e2 of the connection surface C1 of the memory cell array substrate 100 and the control circuit substrate 200 can be suppressed. In this case, the unbonded width b in the radial direction of the semiconductor memory device 1 from the outer periphery e1 to the bonding interface e2 of the connection surface C1 of the memory cell array substrate 100 and control circuit substrate 200 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.

As shown in FIG. 2A, the central portion of the semiconductor memory device 1 includes an effective element region R1 for manufacturing a plurality of semiconductor chips. The outer edge portion of the semiconductor memory device 1 includes a non-effective element region R2. The semiconductor memory device 1 includes the non-effective element region R2 around the effective element region R1. The effective element region R1 is positioned at the center of the semiconductor memory device 1 and has a shape close to a circle in a plan view. The non-effective element region R2 is positioned at the outer edge portion of the semiconductor memory device 1 and has a shape close to a circular ring in a plan view. The non-effective element region R2 circularly surrounds the effective element region R1 in a plan view.

The effective element region R1 includes a memory cell array and a control circuit. On the other hand, the non-effective region R2 may not include a memory cell array or CMOS circuit. The non-effective element region R2 is not electrically connected and does not form a chip, even if there is a wiring or the like. The unbonded width x is arranged within the non-effective element region R2. By suppressing the unbonded width x, the effective element region R1 of the semiconductor memory device 1 can be made larger, and more semiconductor chips can be manufactured.

Structure of Control Circuit Substrate

As shown in FIG. 3, the control circuit substrate 200 includes the substrate 20, a plurality of transistors 26 constituting the control circuit, and a circuit side wiring layer 27. The plurality of transistors 26 is formed in the substrate 20 and electrically connected to the circuit side wiring layer 27 on the other side of the substrate 20. A connecting terminal for connecting with the memory cell array substrate 100 is 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.

Structure of Memory Cell Array Substrate

As shown in FIG. 3, the memory cell array substrate 100 includes the 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 is alternately stacked one by one with a plurality of insulating layers on the substrate 10. Each of the semiconductor pillars 15 is arranged in the vertical direction with respect to the substrate 10 by penetrating through the plurality of stacked electrode layers 16. Each of the semiconductor pillars 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 a memory cell array region 11 (the upper right portion in FIG. 3), the plurality of transistors including memory cells is three-dimensionally arranged. The semiconductor pillar 15 is electrically connected to a source line at one end (the substrate 10 side) and to the memory side wiring layer 17 at the other end (the side opposite to the substrate 10). A connecting terminal for connecting to the control circuit substrate 200 is 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.

A contact region 12 (the upper left portion in FIG. 3) is arranged on the substrate 10, side by side with the memory cell array region 11. In the contact region 12, a terminal portion of each of the plurality of electrode layers 16 is led out in a stepped manner. The respective terminal portions are connected to wirings arranged in the vertical direction via a contact hole opened in an insulating film. The wirings in the vertical direction are electrically connected to the memory side wiring layer 17 and connected to the control circuit substrate 200 via the connecting terminal.

Polishing Apparatus

A polishing apparatus 300 according to the present embodiment will be described with reference to FIG. 4 to FIG. 12.

FIG. 4 is a diagram showing an overall configuration of the polishing apparatus 300. FIG. 5 is a cross-sectional view showing a configuration of the polishing apparatus 300. The polishing apparatus 300 includes a polishing head 400, a rotating platen 500, a polishing pad deformation part 600, and a polishing pad 700.

The polishing head 400 has a shape close to a circle in a plan view, and holds a wafer-shaped (disk-shaped) substrate W. The substrate W is arranged so that the center of the substrate W overlaps the center of the polishing head 400. The polishing head 400 includes a membrane 410 and a control unit 430. The substrate W is held by the polishing head 400 via the membrane 410. The membrane 410 has a shape close to a circle in a plan view and is an airbag made of rubber or synthetic resin with flexibility. The membrane 410 and the substrate W are brought into close contact with each other to make the space between the membrane 410 and the substrate W close to a vacuum, and the pressure difference is utilized to make the entire surface of the polishing head 400 stick onto the substrate W. The substrate W may be the memory cell array substrate 100 or the control circuit substrate 200, may be the substrate 10 or the substrate 20, or may be the semiconductor memory device 1. The polishing head 400 holds the substrate W so that the polished surface of the substrate W faces the polishing pad 700.

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 a plurality of areas in a concentric circle shape about an axial C2 including the center of the polishing head 400, and the pressure of the air may be controlled by the plurality of areas. The air pressure of the membrane 410 may be controlled by the control unit 430.

The polishing head 400 includes a lifter for lifting and lowering the substrate W in the vertical direction (direction Z) with respect to the polishing pad 700. The substrate W during polishing can be pressed against the polishing pad 700 by the lifting and lowering operation of the lifter, and the substrate W before and after polishing can be attached and detached to and from the membrane 410 of the polishing head 400.

The polishing head 400 may include a rotation mechanism 420. The polishing head 400 may rotate about the vertical axial C2 including the center of the polishing head 400 by the rotation mechanism 420. When the polishing head 400 rotates, the substrate W held by the polishing head 400 may rotate about the axial C2 including the center of the substrate W. The rotation operation, the rotation direction, and the rotation speed of the polishing head 400 driven by the rotation mechanism 420 may be controlled by the control unit 430. However, the present disclosure is not limited to this, for example, when the rotating platen 500 rotates, the polishing head 400 may not rotate.

A height sensor 800 may be further arranged below the polishing head 400. The height sensor 800 may detect the position of the polishing head 400 with respect to the rotating platen 500.

The rotating platen 500 is arranged below the polishing head 400 so that the center of the rotating platen 500 overlaps the center of the polishing head 400. The rotating platen 500 has a shape close to a circle in a plan view and holds the disc-shaped polishing pad 700. The polishing pad 700 is arranged so that the center of the polishing pad 700 overlaps the center of the rotating 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 polishing head 400.

The rotating platen 500 includes the polishing pad deformation part 600. FIG. 6 is a top view showing an arrangement of the polishing pad deformation part 600. FIG. 7 is an enlarged cross-sectional view showing a configuration of the polishing pad deformation part 600. The polishing pad deformation part 600 is configured to control the deformation of the polishing pad 700 during polishing as described later.

As shown in FIG. 6 and FIG. 7, the polishing pad deformation part 600 has a circular ring shape, and is arranged below the outer edge portion of the polishing pad 700 in a concentric circle shape about the axial C2 with respect to the rotating platen 500 having a circular shape in a plan view. The polishing pad deformation part 600 is arranged below the outer edge portion of the substrate W (i.e., the rotating platen 500 side) via the polishing pad 700. The polishing pad deformation part 600 includes a contact member 610 contacting the polishing pad 700. The contact member 610 is a rubber or resin such as silicon rubber with flexibility, and the contact member 610 of the polishing pad deformation part 600 and the polishing pad 700 may be fixed with adhesive tape. The contact member 610 has a circular ring shape, and is provided on the outer periphery in a concentric circle shape about the axial C2 with respect to the rotating platen 500 in a plan view, and is arranged 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 periphery of the polishing pad 700.

The polishing pad deformation part 600 can press the polishing pad 700 against the substrate W during polishing or pull it toward the substrate W (adsorption pressure) by controlling the internal air pressure leading to the contact member 610. The polishing pad deformation part 600 is connected to a pipe 570 provided on the rotating platen 500, and has a plurality of openings 630 partitioned into concentric circles so as to be exposed to the contact member 610, and is configured to be capable of controlling the air pressure by the plurality of openings 630. For example, the pipe 570 is connected to a pump or the like, and each of the plurality of openings 630 is configured to be capable of absorbing (adsorbing) or pressurizing the contact member 610. However, the present disclosure is not limited to this, the polishing pad deformation part 600 may include a lifter 620 for lifting and lowering the polishing pad 700 in the vertical direction (direction Z). The lifting and lowering operation of the lifter 620 can press the polishing pad 700 during polishing against the substrate W or pull it away from the substrate W. As described below, the polishing pad deformation part 600 may have the plurality of openings 630 in a concentric circle shape about the axial C2 including the center of the rotating platen 500, and may control pressing or pulling by the plurality of openings 630.

The rotating platen 500 includes a rotation mechanism 520 and a control part 530. The rotating platen 500 rotates about the axial C2 including the center of the rotating platen 500 by the rotation mechanism 520. When the rotating platen 500 rotates, the polishing pad 700 held by the rotating platen 500 rotates about the axial C2 including the center of the polishing pad 700. The rotation operation, the rotation direction, and the rotation speed of the rotating platen 500 driven by the rotation mechanism 520 may be controlled by the control part 530. However, the present disclosure is not limited to this, and when the polishing head 400 rotates, the rotating platen 500 may not rotate.

The rotating platen 500 includes a reservoir (not shown) for liquid delivery, and a pipe 540. The liquid supplier stores water or a chemical solution and supplies it through the pipe 540 to the polished surface of the substrate W (referred to herein as liquid when water or a chemical solution is not distinguished). The liquid supplier is connected to the pipe 540, and supplies the liquid to the pipe 540 while adjusting the flow rate and concentration of the liquid. The pipe 540 penetrates through the polishing pad 700 and supplies the liquid to the surface (substrate W side) of the polishing pad 700.

A plurality of pipes 540 may be arranged. The plurality of pipes 540 may be arranged in a dotted manner on a concentric circle about the axial C2. In this case, the flow rate and concentration of the liquid of the plurality of pipes 540 arranged on one circumference may be collectively controlled.

The rotating platen 500 may further include a slip out prevention device 550. FIG. 8 is a top view showing an arrangement of the slip out prevention device 550. FIG. 9 is an enlarged top view showing a configuration of the slip out prevention device 550.

The slip out prevention device 550 may penetrate through the polishing pad 700 and protrude on the surface (substrate W side) of the polishing pad 700. As shown in FIG. 8, a plurality of slip out prevention devices 550 may be arranged. The slip out prevention device 550 may be arranged in a dotted manner on a concentric circle about the axial C2. Three or more slip out prevention devices 550 are preferably arranged on the concentric circle about the axial C2. The slip out prevention device 550 is arranged on a circumference that is larger than the substrate W and smaller than the polishing pad 700. The slip out prevention device 550 is arranged at the outer edge portion of the polishing pad 700 where the polishing pad deformation part 600 is arranged.

As shown in FIG. 9, for example, the slip out prevention device 550 may be an elliptical cylindrical pin. The slip out prevention device 550 may be able to be rotated, lifted, and lowered inside the through hole of the polishing pad 700. The slip out prevention device 550 may be housed inside the through hole of the polishing pad 700 so that the minor diameter is aligned with the diameter of the polishing pad 700 before and after polishing. During polishing, the slip out prevention device 550 may be able to protrude from the through hole of the polishing pad 700 so that the major axis is aligned with the diameter of the polishing pad 700. With such a configuration, the slip out prevention device 550 can correct the position of the substrate W on the rotating platen 500 with higher precision.

However, the present disclosure is not limited to this, and the polishing head 400 may include a vacuum chuck 440. FIG. 10 is a cross-sectional view showing a configuration of the vacuum chuck 440. As shown in FIG. 10, the polishing head 400 may adsorb the substrate W by the vacuum chuck 440 penetrating through the membrane 410. The vacuum chuck 440 may be arranged in a plurality of areas, and the suction pressure of the air may be controlled by the plurality of areas. If polishing is performed while the vacuum chuck 440 is adsorbed to the back surface of the central portion of the substrate W, the slip out prevention device 550 may not be provided.

The rotating platen 500 may further include a monitor sensor 560. FIG. 11A and FIG. 11B are top views showing an example of an arrangement of the residual film monitor sensor 560.

A light from the monitor sensor 560 penetrates the polishing pad 700 and is exposed to the surface (substrate W side) of the polishing pad 700. For example, the monitor sensor 560 is an optical sensor that measures (detects) a surface film thickness of the substrate W in a non-contact manner. As shown in FIG. 11A, a plurality of monitor sensors 560 may be arranged on the outer edge portion of the polishing pad 700. The monitor sensor 560 may be arranged one by one on a plurality of concentric circles about the axial C2. The monitor sensor 560 detects the surface film thickness of the substrate W at the respective outer peripheral positions. When the monitor sensor 560 detects the surface film thickness of the substrate W at the respective outer peripheral positions, the deformation of the polishing pad 700 can be more finely controlled according to the polishing amount of the substrate W. As shown in FIG. 11A, the plurality of monitor sensors 560 may be arranged at one position. However, the present disclosure is not limited to this, and as shown in FIG. 11B, the plurality of monitor sensors 560 may be distributed in a plurality of positions.

FIG. 12 is a cross-sectional view showing a configuration of a polishing apparatus 300a. The polishing apparatus 300 according to the present embodiment has been described as a Face-down type in which the polishing head 400 is arranged on the rotating platen 500, and the polished surface of the substrate W is arranged downward. However, the present disclosure is not limited to this, and as shown in FIG. 12, the polishing apparatus 300a may be a Face-up type in which the rotating platen 500 is arranged on the polishing head 400 and the polished surface of the substrate W is arranged upward.

Polishing Method A

A polishing method A of a substrate Wa will be described using the polishing apparatus 300 according to the present embodiment. For example, the semiconductor memory device (bonded substrate) 1 of the embodiment is manufactured by bonding the memory cell array substrate 100 and the control circuit substrate 200 which are polished using the polishing method described below. FIG. 13 shows a polishing example A of the substrate Wa. FIG. 14 is a diagram showing the polishing method A of the substrate.

As shown in FIG. 13, in the case where the vicinity of the outer periphery e1 of the substrate Wa has an over-polished shape (referred to as an edge roll-off), in the polishing method A according to the present embodiment, it is preferable that, without changing the roll-off amount za at the outer periphery e1 of the substrate Wa, the roll-off width xa in the radial direction from the outer periphery e1 to the substrate Wa is made to be larger, and the angle θ formed by the outer edge portion and the central portion of the connection surface C100 is polished more gently.

In FIG. 14, the lower part shows the polishing apparatus 300 and the substrate Wa in the middle of the processing in the polishing method A, and the upper part shows the pressure P in the substrate Wa corresponding to the position of the substrate Wa in the horizontal direction in the middle of the processing. In addition, the white arrows shown in FIG. 14 indicate the magnitude and direction of the respective air pressure. The arrows shown in the polishing pad 700 indicate the direction of the pressure.

As shown in FIG. 14, in the case where the substrate Wa has the edge roll-off, the polishing method A according to the present embodiment preferably controls the air pressure of the plurality of openings 630 of the polishing pad deformation part 600. For example, the plurality of openings 630 includes an opening 630a positioned at the outer peripheral side, an opening 630c positioned at the central side, and an opening 630b positioned between the opening 630a and the opening 630c. That is, in the case where the polishing pad deformation part 600 has three concentric openings, the opening 630a below the non-contact region of the substrate Wa and the polishing pad 700, the opening 630b below the region including near the periphery e1 of the substrate Wa, and the opening 630c below the contact region of the substrate Wa and the polishing pad 700, the air pressure of the opening 630c is made to be greater than the air pressure of the opening 630c and the opening 630b, and the polishing pad 700 on the opening 630c is pressed against the substrate Wa. In this case, for example, the air pressure of the openings 630a, 630b, and 630c is pressure. The lifter 620 lowers the polishing pad 700 in the direction away from the substrate Wa against the pressing in the opening 630c during polishing.

In the example of FIG. 14, the pressure applied to the substrate Wa is a pressure P1 applied to the entire contact region of the substrate Wa and the polishing pad 700 through the membrane 410. In the opening 630c, a pressure P2 is further applied by the polishing pad deformation part 600. Since the pressure of the air is small at the opening 630a and the opening 630b, and the lifter 620 lowers the polishing pad 700 in the direction away from the substrate Wa, a pressure P3 applied to the substrate Wa is rapidly reduced toward the non-contact region between the substrate Wa and the polishing pad 700. As a result, in the polishing method A according to the present embodiment, without changing the roll-off amount za of the substrate Wa, the roll-off width xa in the radial direction from the outer periphery e1 to the substate Wa is made to be larger, and the angle θ formed by the outer edge portion and the central portion of the connection surface C100 can be polished more gently.

Polishing Method B

A polishing method B of the substrate Wb will be described using the polishing apparatus 300 according to the present embodiment. FIG. 15 shows a polishing example B of the substrate Wb. FIG. 16 is a diagram showing the polishing method B of the substrate.

As shown in FIG. 15, in the case where the vicinity of the center of the substrate Wb has an over-polished shape (referred to as an edge roll-up), the polishing method B according to the present embodiment preferably polishes only a residual film zb on the outer periphery e1 of the substrate Wb.

In FIG. 16, the lower part shows the polishing apparatus 300 and the substrate Wb in the middle of the processing in the polishing method B, and the upper part shows the pressure P in the substrate Wb corresponding to the position of the substrate Wb in the horizontal direction in the middle of the processing. In addition, the white arrows shown in FIG. 16 indicate the magnitude and direction of the respective air pressure. The arrows shown in the polishing pad 700 indicate the direction of pressure.

As shown in FIG. 16, in the case where the substrate Wb has the edge roll-up, the polishing method B according to the present embodiment preferably controls the air pressure of the plurality of openings 630 of the polishing pad deformation part 600. In the case where the polishing pad deformation part 600 has three concentric openings, the opening 630a below the substrate Wb and the polishing pad 700, the opening 630b below the region including the outer periphery e1 of the substate Wb, and the opening 630c below the contact region of the substrate Wb and the polishing pad 700, the air pressure of the opening 630c may be reduced to be smaller than the air pressure of the opening 630a and the opening 630b, and the polishing pad 700 on the opening 630c may be made not to be too pressed against the substrate Wb. Details thereof will be described later. For example, the air pressure of the opening 630b and the opening 630a is suction pressure, and the air pressure of the opening 630c is pressure. The air pressure of the opening 630c may be smaller than the air pressure of the opening 630a, and the air pressure of the opening 630c may be smaller than the air pressure of the opening 630b.

In the example of FIG. 16, the pressure applied to the substrate Wb is the pressure P1 applied to the entire contact region of the substrate Wb and the polishing pad 700 through the membrane 410. Since the substrate Wb has the convex residual film zb in the vicinity of the outer periphery e1, it is preferable that excessive pressure is not applied to the substrate Wb at the contact portion between the polishing pad 700 and the substrate Wb. For example, by applying suction pressure to the opening 630a and the opening 630b, a reduced pressure P4 is applied to the substrate Wb. In this case, the air pressure of the opening 630c is smaller than the air pressure of the opening 630a and the opening 630b. The air pressure of the opening 630c is pressure. Further, when suction pressure is applied to the opening 630a and the opening 630b, the substrate Wb and the polishing pad 700 may not properly contact each other, so the lifter 620 may be raised to allow the substrate Wb and the polishing pad 700 to properly contact each other. In addition, since the substrate Wb and the polishing pad 700 are not in contact with each other in a region outside the outer periphery e1 of the substrate Wb, a pressure P5 applied to the substrate Wb is zero. As a result, in the polishing method B according to the present embodiment, only the residual film zb on the outer periphery e1 of the substrate Wb can be polished.

MODIFICATION 1

In the polishing method A and the polishing method B according to the present embodiment, the pressure applied to the substrate W was controlled by controlling the deformation of the polishing pad 700 with the polishing pad deformation part 600 of the polishing apparatus 300. However, the present disclosure is not limited to this, and the polishing method according to present modification may further control the pressure applied to the substrate W by controlling the air pressure of the membrane 410. FIG. 17 is a diagram showing a modification of the polishing apparatus and the polishing method of the substrate.

As shown in FIG. 17, in the modification of the polishing apparatus and the polishing method according to the present embodiment, the air pressure of the plurality of areas of the membrane 410 is preferably controlled. In the case where the membrane 410 has three concentric areas, area 410a, area 410b, and area 410c, centered from the outer periphery of the substrate W, the air pressure of the area 410a and the area 410b may be greater than the air pressure of the area 410c, and the substrate W on the area 410a and area 410b may be pressed against the polishing pad 700. In the polishing method according to the present modification, by controlling the air pressure of the membrane 410, the adjustment range may be controlled by area-interference to the range that cannot be dealt with only by controlling the deformation of the polishing pad 700 with the polishing pad deformation part 600.

Modification 2

In the polishing method A and the polishing method B according to the present embodiment, the pressure applied to the substrate W was controlled by controlling the deformation of the polishing pad 700 with the polishing pad deformation part 600 of the polishing apparatus 300. However, the present disclosure is not limited to this, and the polishing method according to the present modification may further control the polishing amount of the substrate W by adjusting the flow rate and concentration of the liquid supplied to the surface of the polishing pad 700. FIG. 18 is a diagram showing the arrangement of a pipe outlet of the pipe 540.

As shown in FIG. 18, in the modification of the polishing method according to the present embodiment, the flow rate and concentration of the liquid supplied to the surface of the polishing pad 700 is preferably controlled. In the case where the plurality of pipes 540, a pipe 540a, a pipe 540b, and a pipe 540c, is arranged from the outer periphery of the substrate W toward the center thereof on three concentric circles, the flow rate of the liquid supplied to the surface of the polishing pad 700 from the pipe 540a may be greater than the flow rate of the liquid supplied to the surface of the polishing pad 700 from the pipe 540b, and the flow rate of the liquid supplied to the surface of the polishing pad 700 from the pipe 540b may be greater than the flow rate of the liquid supplied to the surface of the polishing pad 700 from the pipe 540c. The concentration of the liquid supplied from the pipe 540a to the surface of the polishing pad 700 may be greater than the concentration of the liquid supplied from the pipe 540b to the surface of the polishing pad 700, and the concentration of the liquid supplied from the pipe 540b to the surface of the polishing pad 700 may be greater than the concentration of the liquid supplied from the pipe 540c to the surface of the polishing pad 700. However, it is not limited to this, and the concentration and flow rate of the liquid can be appropriately adjusted by a chemical solution. In addition, for example, the liquid supplied from the pipe 540c to the surface of the polishing pad 700 may be water. In the polishing method according to the present modification, the polishing amount 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.

In the polishing method according to the present embodiment, by controlling the deformation of the polishing pad 700 with the polishing pad deformation part 600, without changing the roll-off amount z of the substrate W, the roll-off width x in the radial direction from the outer periphery e1 to the substrate W is made to be larger, and the angle θ formed by the outer edge portion and the central portion of the connection surface C100 can be polished more gently, thereby improving the planarity of the surface of the substrate W. By improving the planarity of the substrate W, for example, the unbonded region b of the semiconductor memory device (bonded substrate) 1 can be suppressed. By suppressing the unbonded region b, the effective element region R1 of the semiconductor memory device 1 can be made larger, and more semiconductor chips can be manufactured.

While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the novel devices and methods described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modification as would fall within the scope and spirit of the inventions.