Polishing method and polishing system

Abstract

The present invention relates to technology for removing a liquid from the top surface of a wafer before polishing the wafer. In a method according to the present invention: a conveyance device (160), which conveys a workpiece (W) to a polishing device (120A), is brought to an emergency stop on the basis of an emergency stop signal; during the emergency stop of the conveyance device (160), a liquid is supplied to the surface of a polishing head (1) at a transfer position (P2); when the workpiece (W) is at the transfer position (P2) below the polishing head (1), the liquid (Q) is removed from the top surface of the workpiece (W) by the conveyance device (160) on the basis of a stop release signal; the workpiece (W) is then held by the polishing head (1); and the workpiece (W) is polished by pressing the workpiece (W) onto a polishing surface (2a) with the polishing head (1).

Description

Polishing method and polishing system

[0001] The present invention relates to a technique for removing liquid from the top surface of a wafer before the wafer is polished.

[0002] Chemical mechanical polishing (CMP) is a technique for polishing a wafer surface by pressing the wafer against a polishing surface while supplying a polishing liquid onto the polishing surface and sliding the wafer against the polishing surface in the presence of the polishing liquid. During wafer polishing, the wafer is pressed against the polishing surface by a polishing head. The wafer surface is planarized by the chemical action of the polishing liquid and the mechanical action of the abrasive grains contained in the polishing liquid and / or the polishing pad.

[0003] 17 is a cross-sectional view schematically illustrating a polishing head. The polishing head 200 has an elastic membrane 210 that contacts the upper surface of the wafer W1. This elastic membrane 210 has a shape that forms multiple pressure chambers 201 to 204, and the pressure in each of the pressure chambers 201 to 204 can be adjusted independently. Therefore, the polishing head 200 can press multiple regions of the wafer W1 corresponding to these pressure chambers 201 to 204 with different forces, thereby achieving a desired film thickness profile on the wafer W1.

[0004] When polishing of wafer W1 is completed, the polished wafer W1 is transported to the next process by the transport device. As shown in Figure 18, the next wafer W2 is transported by the transport device to a transfer position below the polishing head 200. At the same time, the polishing head 200 is washed with a liquid (e.g., pure water) supplied from the cleaning nozzle 215, and the polishing liquid and polishing debris are removed from the polishing head 200. Then, the next wafer W2 is held by the polishing head 200 and transported by the polishing head 200 to a position above the polishing surface. The wafer W2 is pressed against the polishing surface by the polishing head 200 and polished in the presence of the polishing liquid.

[0005] 19 , however, liquid Q used to clean the polishing head 200 may be present between the upper surface of the wafer W2 and the elastic membrane 210 of the polishing head 200. If liquid Q is present between the upper surface of the wafer W2 and the polishing head 200, the polishing head 200 cannot properly apply force to multiple regions of the wafer W2 corresponding to the pressure chambers 201 to 204. For example, if liquid Q spreads across multiple pressure chambers, the pressure in an adjacent pressure chamber is transmitted to liquid Q, and an unintended force is applied to the wafer W2.

[0006] Therefore, there is a technique for removing the liquid Q from the wafer W2 by a transfer device before polishing the wafer W2 (for example, Patent Document 1). This technique is expected to enable the polishing head 200 to apply an appropriate force to the wafer W2.

[0007] JP 2023-90770 A

[0008] When an error such as an apparatus malfunction or a liquid leak is detected in the polishing apparatus, the transport device may be brought to an emergency stop and the next wafer may be made to wait at the transfer position. In such a case, in order to prevent the surface of the polishing head 200 from drying, liquid is again supplied to the polishing head 200 from the cleaning nozzle 215. As a result, even after the liquid Q has already been removed from the upper surface of the wafer, the liquid supplied to the polishing head 200 may fall again onto the wafer.

[0009] Therefore, the present invention provides a polishing method and polishing system in which, after liquid is supplied to the polishing head by an emergency stop of the conveying device, the liquid that has fallen onto the top surface of the wafer can be removed from the top surface of the wafer, and the polishing head can apply an appropriate force to the wafer.

[0010] In one aspect, a polishing method is provided, which includes emergency stopping a transport device transporting a workpiece to a polishing apparatus based on an emergency stop signal, supplying liquid to a surface of a polishing head of the polishing apparatus at a transfer position while the transport device is stopped, and removing the liquid from an upper surface of the workpiece by the transport device based on a stop release signal when the workpiece is at the transfer position below the polishing head, and then holding the workpiece at the transfer position with the polishing head and pressing the lower surface of the workpiece against a polishing surface with the polishing head to polish the lower surface of the workpiece. In one aspect, removing the liquid from the upper surface of the workpiece by the transport device involves moving the workpiece horizontally with the transport device to remove the liquid from the upper surface of the workpiece. In one aspect, the horizontal movement distance of the workpiece by the transport device is equal to or greater than the diameter of the workpiece.

[0011] In one aspect, removing the liquid from the upper surface of the workpiece by the transport device comprises tilting the workpiece by the transport device to remove the liquid from the upper surface of the workpiece. In one aspect, the tilt angle of the workpiece by the transport device is 45 degrees or more. In one aspect, the transport device is a linear-motion type transport device including a horizontal linear motion mechanism that moves the workpiece along an X-axis extending horizontally. In one aspect, the transport device is a horizontal articulated robot.

[0012] In one aspect, a polishing system is provided, comprising: a polishing apparatus for polishing a workpiece; a transport device for transporting the workpiece to the polishing apparatus; and an operation control unit for controlling the operation of the polishing apparatus and the transport device, wherein the polishing apparatus comprises a polishing head for pressing the workpiece against a polishing surface, and a liquid supply nozzle for supplying liquid to a surface of the polishing head, and the operation control unit is configured to: emergency stop the transport device based on an emergency stop signal; during the emergency stop of the transport device, issue a command to the liquid supply nozzle to supply the liquid to the surface of the polishing head at a transfer position; when the workpiece is at the transfer position below the polishing head, issue a command to the transport device based on a stop release signal to remove the liquid from the upper surface of the workpiece, then issue a command to the polishing head to hold the workpiece at the transfer position, and issue a command to the polishing head to press the lower surface of the workpiece against the polishing surface, thereby polishing the lower surface of the workpiece. In one aspect, the transport device includes a transport stage on which the workpiece is placed and a horizontal movement mechanism that moves the transport stage in a horizontal direction, and the operation control unit is configured to issue a command to the horizontal movement mechanism to move the transport stage in the horizontal direction, thereby removing the liquid from the upper surface of the workpiece. In one aspect, the horizontal movement distance of the workpiece by the transport device is equal to or greater than the diameter of the workpiece.

[0013] In one aspect, the transport device includes a transport stage on which the workpiece is placed and a tilting mechanism that tilts the transport stage, and the operation control unit is configured to issue a command to the tilting mechanism to tilt the transport stage and thereby remove the liquid from the upper surface of the workpiece. In one aspect, the tilt angle of the workpiece caused by the transport device is 45 degrees or more. In one aspect, the transport device is a linear-motion transport device that moves the workpiece along an X-axis extending horizontally. In one aspect, the transport device is a horizontal articulated robot.

[0014] According to the present invention, even if the liquid supplied to the polishing head falls onto the upper surface of the wafer during an emergency stop of the transfer device, the liquid is removed from the upper surface of the wafer by the transfer device before the wafer is polished. As a result, the polishing head can apply the intended force to the wafer, thereby achieving the desired film thickness profile of the wafer.

[0015] 1 is a plan view schematically showing an embodiment of a polishing system. FIG. 2 is a schematic view showing an embodiment of a polishing apparatus. FIG. 3 is a cross-sectional view showing an embodiment of the polishing head shown in FIG. 2. FIG. 4 is a top view showing an embodiment of a transport apparatus. FIG. 5 is a view explaining how the transport apparatus moves a wafer in a horizontal direction. FIG. 6 is a view explaining how the transport apparatus moves the wafer in a horizontal direction, thereby removing liquid from the upper surface of the wafer. FIG. 7 is a schematic view showing another embodiment of the transport apparatus. FIG. 8 is a view of the transport apparatus shown in FIG. 7 from the direction indicated by arrow A. FIG. 9 is a view explaining how the transport apparatus tilts the wafer, thereby removing liquid from the upper surface of the wafer. FIG. 10 is a top view of the transport apparatus shown in FIG. 10. FIG. 11 is a view explaining how the transport apparatus moves a wafer to a transfer position. FIG. 12 is a view explaining how the transport apparatus moves the wafer in a horizontal direction. FIG. 13 is a schematic view showing another embodiment of the transport apparatus. FIG. 14 is a view explaining how the transport apparatus tilts the wafer, thereby removing liquid from the upper surface of the wafer. 1A and 1B are diagrams illustrating the polishing head being cleaned, and 1C are diagrams illustrating problems caused by liquid existing between the top surface of the wafer and the elastic membrane of the polishing head.

[0016] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] An embodiment of the present invention will now be described with reference to the accompanying drawings. Fig. 1 is a plan view schematically illustrating one embodiment of a polishing system 100. The polishing system 100 of this embodiment is a system for polishing wafers, which are an example of workpieces. Specific examples of workpieces include wafers, wiring substrates, and square substrates used in the manufacture of semiconductor devices.

[0017] As shown in FIG. 1, the polishing system 100 includes a load port 110 on which a substrate cassette containing a plurality of wafers to be processed is placed, a plurality of polishing apparatuses 120A, 120B, 120C, and 120D (four in this embodiment) for polishing the wafers, cleaning apparatuses 130A and 130B for cleaning the wafers after polishing, a drying apparatus 140 for drying the wafers after cleaning, and transport apparatuses 150, 160, 170, and 180 for transporting the wafers.

[0018] The polishing apparatuses 120A to 120D are arranged along the longitudinal direction of the polishing system 100. A wafer to be polished is transferred from the load port 110 to the transfer apparatus 160 by the transfer apparatus 150, and then transferred to one of the polishing apparatuses 120A to 120D by the transfer apparatus 160, where the polishing process is performed. The wafer may be polished sequentially by the multiple polishing apparatuses.

[0019] After polishing, the wafer is transferred by the transfer device 160 to either the cleaning device 130A or 130B, where the cleaning process is performed. In one embodiment, the wafer may be sequentially cleaned in the cleaning devices 130A and 130B. The transfer device 170 transfers the wafer between the cleaning device 130A and the cleaning device 130B.

[0020] After the cleaning process, the wafer is transferred by the transfer device 180 to the drying device 140, where it is dried. The dried wafer is returned to the load port 110 by the transfer device 150. The specific configuration of the polishing system 100 is not particularly limited to this embodiment. For example, the polishing system 100 may include a single polishing device, a single cleaning device, or multiple transfer devices 160. The polishing system 100 may also include a temporary storage table on which the wafer waits until the next process is performed.

[0021] The polishing system 100 further includes an operation control unit 190 that controls the operations of the polishing apparatuses 120A to 120D, the cleaning apparatuses 130A and 130B, the drying apparatus 140, and the transport apparatuses 150, 160, 170, and 180. The polishing apparatuses 120A to 120D, the cleaning apparatuses 130A and 130B, the drying apparatus 140, and the transport apparatuses 150, 160, 170, and 180 are electrically connected to the operation control unit 190.

[0022] The operation control unit 190 includes a storage device 190a that stores a program and an arithmetic unit 190b that executes calculations according to instructions included in the program. The operation control unit 190 is composed of at least one computer. The storage device 190a includes a main storage device such as a random access memory (RAM) and an auxiliary storage device such as a hard disk drive (HDD) or a solid state drive (SSD). Examples of the arithmetic unit 190b include a CPU (central processing unit) and a GPU (graphics processing unit). However, the specific configuration of the operation control unit 190 is not limited to these examples.

[0023] FIG. 2 is a schematic diagram showing one embodiment of the polishing apparatus 120A. The polishing apparatus 120A will be described below, but the polishing apparatuses 120A to 120D basically have the same configuration. As shown in FIG. 2, the polishing apparatus 120A includes a polishing table 3 that supports a polishing pad 2, a polishing head 1 that presses a wafer W against the polishing pad 2, a table motor 6 that rotates the polishing table 3, and a polishing liquid supply nozzle 5 that supplies a polishing liquid (e.g., a slurry containing abrasive grains) onto the polishing pad 2. The surface of the polishing pad 2 forms a polishing surface 2a that polishes the wafer W.

[0024] The polishing table 3 is connected to a table motor 6, which rotates the polishing table 3 and the polishing pad 2 together. The polishing head 1 is fixed to the end of a polishing head shaft 11, which is rotatably supported by a head arm 15. The head arm 15 is rotatably supported by a support shaft 16.

[0025] The polishing head 1, the polishing liquid supply nozzle 5, and the table motor 6 are electrically connected to the operation control unit 190, and the operations of the polishing head 1, the polishing liquid supply nozzle 5, and the table motor 6 are controlled by the operation control unit 190.

[0026] The wafer W is polished as follows. The operation control unit 190 issues commands to the table motor 6, polishing head 1, and polishing liquid supply nozzle 5 to rotate the polishing table 3 and polishing head 1 in the directions indicated by the arrows in FIG. 2 while supplying polishing liquid from the polishing liquid supply nozzle 5 to the polishing surface 2a of the polishing pad 2 on the polishing table 3. The operation control unit 190 issues a command to the polishing head 1 to press the underside of the wafer W against the polishing surface 2a of the polishing pad 2 with the polishing liquid present between the polishing pad 2 and the wafer W. The underside of the wafer W is polished by the chemical action of the polishing liquid and the mechanical action of the abrasive grains contained in the polishing liquid and / or the polishing pad 2.

[0027] Next, the polishing head 1 will be described. Fig. 3 is a cross-sectional view showing one embodiment of the polishing head 1 shown in Fig. 2. The polishing head 1 includes a carrier 31 fixed to the end of the polishing head shaft 11, an elastic membrane 34 attached to the lower part of the carrier 31, and a retainer ring 32 disposed below the carrier 31. The retainer ring 32 is disposed around the elastic membrane 34. The retainer ring 32 is an annular structure that holds the wafer W to prevent the wafer W from jumping out of the polishing head 1 during polishing.

[0028] The elastic membrane 34 includes a contact portion 35 having a contact surface 35a that can contact the upper surface of the wafer W, and inner wall portions 36a, 36b, 36c and an outer wall portion 36d connected to the contact portion 35. The contact portion 35 has substantially the same size and shape as the upper surface of the wafer W. The inner wall portions 36a, 36b, 36c and the outer wall portion 36d are endless walls arranged concentrically. The outer wall portion 36d is located outside the inner wall portions 36a, 36b, 36c and is arranged to surround the inner wall portions 36a, 36b, 36c. In this embodiment, three inner wall portions 36a, 36b, 36c are provided, but the present invention is not limited to this embodiment. In an embodiment, only one or two inner wall portions may be provided, or four or more inner wall portions may be provided.

[0029] Four pressure chambers 25A, 25B, 25C, and 25D are provided between the elastic membrane 34 and the carrier 31. The pressure chambers 25A, 25B, 25C, and 25D are formed by the contact portion 35 of the elastic membrane 34, inner wall portions 36a, 36b, and 36c, and outer wall portion 36d. That is, the pressure chamber 25A is located within the inner wall portion 36a, the pressure chamber 25B is located between the inner wall portion 36a and the inner wall portion 36b, the pressure chamber 25C is located between the inner wall portion 36b and the inner wall portion 36c, and the pressure chamber 25D is located between the inner wall portion 36c and the outer wall portion 36d. The central pressure chamber 25A is circular, and the other pressure chambers 25B, 25C, and 25D are annular. These pressure chambers 25A, 25B, 25C, and 25D are arranged concentrically. The pressure chamber 25B is located outside the pressure chamber 25A, the pressure chamber 25C is located outside the pressure chamber 25B, and the pressure chamber 25D is located outside the pressure chamber 25C.

[0030] An annular membrane (rolling diaphragm) 37 is disposed between the carrier 31 and the retainer ring 32, and a pressure chamber 25E is formed inside this membrane 37. Gas transfer lines F1, F2, F3, F4, and F5 are connected to the pressure chambers 25A, 25B, 25C, 25D, and 25E, respectively. The gas transfer lines F1, F2, F3, F4, and F5 extend via a rotary joint 40 attached to the polishing head shaft 11.

[0031] The gas transfer lines F1, F2, F3, F4, and F5 are connected to a compressed gas supply source (not shown) that serves as a utility supply source provided in the factory where the polishing apparatus 120A is installed. Compressed gas such as compressed air is supplied to the pressure chambers 25A, 25B, 25C, 25D, and 25E through the gas transfer lines F1, F2, F3, F4, and F5, respectively.

[0032] The gas transfer lines F1, F2, F3, F4, and F5 extend via a rotary joint 40 attached to the polishing head shaft 11. The gas transfer lines F1, F2, F3, F4, and F5, which communicate with the pressure chambers 25A, 25B, 25C, 25D, and 25E, are provided with pressure regulators R1, R2, R3, R4, and R5, respectively. Compressed gas from a compressed gas supply source is supplied independently into the pressure chambers 25A to 25E through the pressure regulators R1 to R5. The pressure regulators R1 to R5 are configured to adjust the pressure of the compressed gas in the pressure chambers 25A to 25E.

[0033] The pressure regulators R1 to R5 can independently change the internal pressures of the pressure chambers 25A to 25E. This allows the pressure regulators R1 to R5 to independently adjust the polishing pressures for the four corresponding regions of the wafer W, namely, the center, inner middle, outer middle, and edge regions, and the pressing force of the retainer ring 32 against the polishing surface 2a of the polishing pad 2. The gas transfer lines F1, F2, F3, F4, and F5 are also connected to atmospheric relief valves (not shown), allowing the pressure chambers 25A to 25E to be opened to the atmosphere. In this embodiment, the elastic membrane 34 forms four pressure chambers 25A to 25D. However, in another embodiment, the elastic membrane 34 may form fewer or more than four pressure chambers.

[0034] The pressure regulators R1 to R5 are connected to an operation control unit 190. The operation control unit 190 sends target pressure values ​​for the pressure chambers 25A to 25E to the pressure regulators R1 to R5, and the pressure regulators R1 to R5 operate to maintain the pressures in the pressure chambers 25A to 25E at the corresponding target pressure values.

[0035] The polishing head 1 can apply independent polishing pressures to multiple regions of the wafer W. For example, the polishing head 1 can press different regions of the surface of the wafer W against the polishing surface 2 a of the polishing pad 2 with different polishing pressures. Therefore, the polishing head 1 can control the film thickness profile of the wafer W to achieve a target film thickness profile.

[0036] Vacuum lines L1, L2, L3, L4, and L5 are connected to gas transfer lines F1, F2, F3, F4, and F5, respectively. Vacuum valves V1, V2, V3, V4, and V5 are attached to vacuum lines L1, L2, L3, L4, and L5, respectively. Vacuum valves V1, V2, V3, V4, and V5 are actuator-driven valves such as solenoid valves, electric valves, or air-operated valves. Vacuum valves V1 to V5 are connected to an operation control unit 190, and their operation is controlled by the operation control unit 190. When vacuum lines L1, L2, L3, L4, and L5 are opened, a vacuum is created in the corresponding pressure chambers 25A, 25B, 25C, 25D, and 25E.

[0037] In one embodiment in which the polishing head 1 holds the wafer W, vacuum valves V2, V3, and V4 are opened to create a vacuum in the pressure chambers 25B, 25C, and 25D while the contact portion 35 of the elastic membrane 34 is in contact with the wafer W. The contact portion 35 of the elastic membrane 34 does not have any through holes to allow fluid to flow in or out. Therefore, the portions of the contact portion 35 that form the pressure chambers 25A, 25B, and 25C are depressed upward by the vacuum, allowing the polishing head 1 to suction the wafer W due to the suction effect of the elastic membrane 34. Furthermore, by operating the pressure regulators R2, R3, and R4 to supply compressed gas to the pressure chambers 25B, 25C, and 25D, the suction effect is released, allowing the polishing head 1 to release the wafer W.

[0038] FIG. 4 is a top view showing one embodiment of the transfer device 160. FIG. 4 illustrates the transfer device 160 transferring a wafer W to the polishing apparatus 120A. The transfer device 160 of this embodiment is a linear-motion transfer device that moves the wafer W along the horizontal X-axis. As shown in FIG. 4, the polishing head 1 is movable between a polishing position P1 indicated by a solid line and a transfer position P2 indicated by a dotted line. More specifically, the head arm 15 rotates around the support shaft 16, allowing the polishing head 1 to move between the polishing position P1 and the transfer position P2. The polishing position P1 is located above the polishing surface 2a of the polishing pad 2, and the transfer position P2 is located outside the polishing surface 2a. The wafer W is transferred to the transfer position P2 of the polishing apparatus 120A by the transfer device 160.

[0039] The transfer device 160 of this embodiment includes a transfer stage 51 on which the wafer W is placed, an elevator mechanism 52 that moves the transfer stage 51 up and down, and a horizontal movement mechanism 53 that moves the transfer stage 51 and the elevator mechanism 52 together in the horizontal direction. The elevator mechanism 52 is connected to the transfer stage 51. The horizontal movement mechanism 53 is connected to the transfer stage 51 via the elevator mechanism 52.

[0040] The lifting mechanism 52 may include, but is not limited to, a combination of a ball screw and a servo motor, a combination of a pulley, a belt, and an electric motor, an air cylinder, a linear motor, or other actuator (not shown). In one embodiment, the transport device 160 does not necessarily have to include the lifting mechanism 52.

[0041] The horizontal movement mechanism 53 is configured to move the wafer W along the X-axis extending horizontally. The X-axis coincides with the longitudinal direction of the polishing system 100 (i.e., the direction in which the polishing apparatuses 120A to 120D are arranged) (see FIG. 1). The horizontal movement mechanism 53 includes an actuator (not shown) such as a combination of a ball screw and a servo motor, a combination of a pulley, a belt, and an electric motor, an air cylinder, or a linear motor, but the configuration thereof is not particularly limited.

[0042] The lifting mechanism 52 and the horizontal movement mechanism 53 are electrically connected to the operation control unit 190 , and the operations of the lifting mechanism 52 and the horizontal movement mechanism 53 are controlled by the operation control unit 190 .

[0043] The wafer W to be polished next is placed on the transfer stage 51 and is moved together with the transfer stage 51 by the horizontal movement mechanism 53 to a transfer position P2 below the polishing head 1. When the polishing head 1 is at the transfer position P2, the lifting mechanism 52 raises the transfer stage 51. The polishing head 1 holds the wafer W on the transfer stage 51 and moves together with the wafer W to the polishing position P1.

[0044] After polishing the wafer W, the polishing head 1 moves to the transfer position P2 together with the wafer W. Then, the polishing head 1 releases the wafer W and places it on the transfer stage 51 of the transfer device 160 located at the transfer position P2. The transfer device 160 moves the wafer W to the next process (for example, one of the polishing devices 120B to 120D or one of the cleaning devices 130A, 130B) (see FIG. 1).

[0045] The polishing apparatus 120A further includes a liquid supply nozzle 55 that supplies a liquid (e.g., a rinse liquid such as pure water) to the polishing head 1 located at the transfer position P2 to clean the polishing head 1. The liquid supply nozzle 55 is electrically connected to the operation control unit 190, and the operation of the liquid supply nozzle 55 is controlled by the operation control unit 190.

[0046] The liquid supply nozzle 55 is disposed facing the polishing head 1 at the transfer position P2. The liquid supply nozzle 55 is configured to supply liquid to the surface of the polishing head 1. The surface of the polishing head 1 includes the surface of the elastic membrane 34 and the surface of the retaining ring 32 (see FIG. 3). The surface of the polishing head 1 from which the wafer W has been released is cleaned with the liquid supplied from the liquid supply nozzle 55.

[0047] In this embodiment, while the polishing head 1 is being cleaned, the next wafer W is moved to the transfer position P2 below the polishing head 1 by the horizontal movement mechanism 53 of the transport device 160. As a result, while the polishing head 1 is being cleaned, liquid falls onto the upper surface of the wafer W at the transfer position P2 below the polishing head 1. As described with reference to FIG. 19 , the liquid present on the upper surface of the wafer W prevents the polishing head 1 from applying an appropriate force to the wafer W.

[0048] Therefore, as shown in FIG. 5 , the horizontal movement mechanism 53 of the transfer device 160 moves the wafer W horizontally before the wafer W is held by the polishing head 1. In this embodiment, the transfer device 160 moves the wafer W back and forth horizontally between the transfer position P2 and the turning position P3. That is, the transfer device 160 moves the wafer W horizontally from the transfer position P2 to the turning position P3, and then moves the wafer W horizontally from the turning position P3 to the transfer position P2. In one embodiment, the horizontal movement distance D of the wafer W by the transfer device 160, i.e., the distance between the transfer position P2 and the turning position P3, is equal to or greater than the diameter of the wafer W. As shown in FIG. 6 , when the wafer W is moved horizontally, the liquid Q spills from the upper surface of the wafer W, thereby removing the liquid Q from the upper surface of the wafer W.

[0049] After the liquid Q has been removed from the upper surface of the wafer W, the lifting mechanism 52 raises the transfer stage 51 on which the next wafer W is placed. Then, the polishing head 1 holds the wafer W and moves it to a polishing position P1 (see FIG. 4) above the polishing pad 2. Thereafter, the polishing head 1 presses the lower surface of the wafer W against the polishing surface 2a of the polishing pad 2, thereby polishing the lower surface of the wafer W. In this manner, multiple wafers are polished successively.

[0050] In one embodiment, the polishing head 1 may be cleaned while the polished wafer W released from the polishing head 1 is at the transfer position P2 on the transfer stage 51. In this case, the transfer device 160 may remove the liquid Q from the upper surface of the polished wafer W by horizontal movement when transferring the polished wafer W to the next polishing device. For example, the transfer device 160 removes the liquid Q from the upper surface of the wafer W by horizontal movement when transferring the wafer W from the polishing device 120A to the polishing device 120B. Cleaning of the polishing head 1 is completed before the next wafer W is transferred to the transfer position P2.

[0051] In the polishing system 100, if an error such as an equipment malfunction or a liquid leak is detected, it is necessary to urgently stop one of the transport devices 150, 160, 170, and 180 that should be stopped so that wafers are not transported to the device that will perform the next processing. In this embodiment, the operation control unit 190 is configured to urgently stop the transport device 160 based on an emergency stop signal. Examples of emergency stop signals include a signal indicating an equipment malfunction or error detected by a detection device (not shown) and a signal input by a user through an input device (not shown). The detection device and the input device are connected to the operation control unit 190, and the emergency stop signal from the detection device and the input device is sent to the operation control unit 190.

[0052] In one embodiment, when the wafer on the transport device 160 is located closer to the transfer position P2 of the polishing device to be processed next (e.g., polishing device 120A), the operation control unit 190 may, based on an emergency stop signal, cause the transport device 160 to move the wafer to the transfer position P2 of the polishing device to be processed next (e.g., polishing device 120A), and then cause the transport device 160 to make an emergency stop.

[0053] During the emergency stop of the transport device 160, the operation control unit 190 issues a command to the liquid supply nozzle 55 to supply liquid to the surface of the polishing head 1 in order to prevent the surface of the polishing head 1 from drying out. If liquid is supplied to the surface of the polishing head 1 while the wafer W on the transport stage 51 is at the transfer position P2, the liquid supplied to the surface of the polishing head 1 will fall onto the wafer W.

[0054] Therefore, in this embodiment, the operation control unit 190 is configured to issue a command to the transport device 160 based on the stop release signal when the wafer W is at the transfer position P2 to remove the liquid from the upper surface of the wafer W. The operation control unit 190 is also configured to issue a command to the liquid supply nozzle 55 to stop supplying the liquid to the surface of the polishing head 1. The stop release signal is a signal that instructs the restart of operation of the device (in this embodiment, the transport device 160) that has been stopped in an emergency when the device abnormality or error is eliminated, and is input to the operation control unit 190.

[0055] 5 and 6, the operation of removing the liquid from the upper surface of the wafer W will not be described again. After the liquid Q has been removed from the upper surface of the wafer W, the polishing head 1 holds the wafer W and moves the wafer W to a polishing position P1 (see FIG. 4) above the polishing pad 2. Thereafter, the polishing head 1 presses the lower surface of the wafer W against the polishing surface 2a of the polishing pad 2, thereby polishing the lower surface of the wafer W.

[0056] According to this embodiment, even if the liquid supplied to the polishing head 1 falls onto the upper surface of the wafer W during an emergency stop of the transport device 160, the liquid is removed from the upper surface of the wafer W by the transport device 160 before polishing the wafer W. As a result, the polishing head 1 can apply an intended force to the wafer W, and a desired film thickness profile of the wafer W can be achieved.

[0057] 7 is a schematic diagram showing another embodiment of the transfer device 160. Details of this embodiment that are not specifically described are the same as those of the above-described embodiment, and therefore redundant description will be omitted. As shown in FIG. 7, the transfer device 160 of this embodiment is equipped with a tilting mechanism 57 that tilts the transfer stage 51. This tilting mechanism 57 is held by the lifting mechanism 52 and moves up and down integrally with the transfer stage 51.

[0058] The tilting mechanism 57 has a support shaft 57a extending horizontally and a rotation device 57b that rotates the support shaft 57a. The support shaft 57a is connected to the transfer stage 51, and the rotation device 57b is fixed to the lifting mechanism 52. The rotation device 57b is configured to rotate the support shaft 57a and the transfer stage 51 by a predetermined angle. The rotation device 57b is equipped with an actuator (not shown) such as a servo motor. The tilting mechanism 57 (specifically, the rotation device 57b) is electrically connected to the operation control unit 190, and the operation of the tilting mechanism 57 (specifically, the rotation device 57b) is controlled by the operation control unit 190.

[0059] The next wafer W to be polished is placed on the transfer stage 51 and moved together with the transfer stage 51 to a transfer position P2 below the polishing head 1 by the horizontal movement mechanism 53. Before holding the next wafer W, the polishing head 1 is cleaned with liquid supplied from a liquid supply nozzle 55. The liquid used to clean the polishing head 1 falls onto the upper surface of the wafer W on the transfer stage 51. Figure 8 is a view of the transfer device 160 shown in Figure 7 as viewed from the direction indicated by arrow A. As shown in Figure 8, a liquid Q is present on the upper surface of the wafer W.

[0060] 9 , the tilting mechanism 57 of the transfer device 160 tilts the transfer stage 51 and the wafer W together before the wafer W is held by the polishing head 1. In one embodiment, the tilt angle θ of the wafer W by the transfer device 160 is 45 degrees or more. When the wafer W is tilted, the liquid Q spills from the upper surface of the wafer W, and the liquid Q is thereby removed from the upper surface of the wafer W. In one embodiment, with the transfer stage 51 and the wafer W tilted by the tilting mechanism 57, the horizontal movement mechanism 53 may move the transfer stage 51 and the wafer W in the horizontal direction.

[0061] After the liquid Q is removed from the upper surface of the wafer W, the tilting mechanism 57 returns the wafer W to a horizontal position. The polishing head 1 holds the wafer W and moves it to a polishing position P1 (see FIG. 4) above the polishing pad 2. Thereafter, the polishing head 1 presses the lower surface of the wafer W against the polishing surface 2a of the polishing pad 2, thereby polishing the lower surface of the wafer W.

[0062] In one embodiment, the polishing head 1 may be cleaned while the polished wafer W released from the polishing head 1 is at the transfer position P2 on the transfer stage 51. In this case, the transfer device 160 may remove the liquid Q from the upper surface of the wafer W by horizontal movement when transferring the polished wafer W to the next polishing device (or by horizontal movement with the transfer stage 51 and the wafer W tilted by the tilting mechanism 57). Cleaning of the polishing head 1 is completed before the next wafer W is transferred to the transfer position P2.

[0063] In this embodiment, the operation control unit 190 also brings the transport device 160 to an emergency stop based on the emergency stop signal. During the emergency stop of the transport device 160, the operation control unit 190 issues a command to the liquid supply nozzle 55 to supply liquid to the surface of the polishing head 1 in order to prevent the surface of the polishing head 1 from drying out. When liquid is supplied to the surface of the polishing head 1 while the wafer W on the transport stage 51 is at the transfer position P2, the liquid supplied to the surface of the polishing head 1 falls onto the wafer W.

[0064] When the wafer W is at the transfer position P2, the operation control unit 190 issues a command to the transport device 160 based on the stop release signal to remove the liquid from the upper surface of the wafer W. The operation control unit 190 is also configured to issue a command to the liquid supply nozzle 55 to stop supplying the liquid to the surface of the polishing head 1. The operation of removing the liquid from the upper surface of the wafer W is the same as the operation described with reference to FIGS. 8 and 9 , so a redundant description will be omitted. After the liquid Q is removed from the upper surface of the wafer W, the tilting mechanism 57 returns the wafer W to a horizontal position. The polishing head 1 holds the wafer W and moves it to the polishing position P1 (see FIG. 4 ) above the polishing pad 2. The polishing head 1 then presses the lower surface of the wafer W against the polishing surface 2 a of the polishing pad 2, thereby polishing the lower surface of the wafer W.

[0065] According to this embodiment, even if the liquid supplied to the polishing head 1 falls onto the upper surface of the wafer W during an emergency stop of the transport device 160, the liquid is removed from the upper surface of the wafer W by the transport device 160 before polishing the wafer W. As a result, the polishing head 1 can apply an intended force to the wafer W, and a desired film thickness profile of the wafer W can be achieved.

[0066] FIG. 10 is a side view schematically illustrating yet another embodiment of the transfer device 160, and FIG. 11 is a top view of the transfer device 160 shown in FIG. Details of this embodiment that are not particularly described are the same as those of the embodiment described with reference to FIGS. 1 to 6 , and therefore, redundant description will be omitted. The transfer device 160 of this embodiment is a horizontal articulated robot (SCARA robot). As shown in FIGS. 10 and 11 , the transfer device 160 of this embodiment includes a transfer stage 61 on which a wafer W is placed, a first arm 62 connected to the transfer stage 61, a first rotation mechanism (first joint) 64 that rotates the first arm 62, a second arm 63 connected to the first arm 62 via the first rotation mechanism 64, a second rotation mechanism (second joint) 65 that rotates the second arm 63, and an elevator mechanism 67 that moves the second arm 63 up and down.

[0067] The first rotation mechanism 64 is configured to rotate the first arm 62 about its rotation axis. The second rotation mechanism 65 is configured to rotate the second arm 63 about its rotation axis. Each of the first rotation mechanism 64 and the second rotation mechanism 65 has an actuator (not shown) such as a servo motor, but the configuration thereof is not particularly limited. The wafer W on the transfer stage 61 is moved in the horizontal direction by a combination of the rotation of the first arm 62 by the first rotation mechanism 64 and the rotation of the second arm 63 by the second rotation mechanism 65. In the transfer device 160 of this embodiment, the horizontal movement mechanism that moves the transfer stage 61 horizontally is a combination of the first rotation mechanism 64 and the second rotation mechanism 65.

[0068] The lifting mechanism 67 has an actuator (not shown) such as an air cylinder, but the configuration thereof is not particularly limited. When the lifting mechanism 67 moves the second rotation mechanism 65 up and down, the transfer stage 61, the first arm 62, the first rotation mechanism 64, and the second arm 63 are moved up and down as a unit. The configuration of the transfer device 160, which is a horizontal articulated robot, is not limited to this embodiment. For example, the lifting mechanism 67 may be connected to the transfer stage 61, or the transfer device 160 may not include the lifting mechanism 67.

[0069] The first rotation mechanism 64, the second rotation mechanism 65, and the lifting mechanism 67 are electrically connected to the operation control unit 190, and the operations of the first rotation mechanism 64, the second rotation mechanism 65, and the lifting mechanism 67 are controlled by the operation control unit 190.

[0070] 12, the wafer W to be polished next is placed on the transfer stage 61 and is moved together with the transfer stage 61 to a transfer position P2 below the polishing head 1 by the first rotation mechanism 64 and the second rotation mechanism 65. Before holding the next wafer W, the polishing head 1 is cleaned with liquid supplied from the liquid supply nozzle 55. The liquid used to clean the polishing head 1 falls onto the upper surface of the wafer W on the transfer stage 61.

[0071] In this embodiment, as shown in FIG. 13 , the first rotation mechanism 64 and the second rotation mechanism 65 of the transfer device 160 move the wafer W horizontally to remove the liquid from the upper surface of the wafer W before the wafer W is held by the polishing head 1. In this embodiment, the transfer device 160 moves the wafer W back and forth horizontally between the transfer position P2 and the turning position P3. That is, the transfer device 160 moves the wafer W horizontally from the transfer position P2 to the turning position P3, and then moves the wafer W horizontally from the turning position P3 to the transfer position P2. In one embodiment, the horizontal movement distance D of the wafer W by the transfer device 160, i.e., the distance between the transfer position P2 and the turning position P3, is equal to or greater than the diameter of the wafer W. As a result, as described with reference to FIG. 6 , when the wafer W is moved horizontally, the liquid Q spills from the upper surface of the wafer W, thereby removing the liquid Q from the upper surface of the wafer W.

[0072] In this embodiment, the transfer device 160 moves the wafer W back and forth horizontally in a straight line between the transfer position P2 and the turning position P3. However, in another embodiment, the transfer device 160 may move the wafer W back and forth horizontally between the transfer position P2 and the turning position P3 along an arc-shaped trajectory. For example, the first rotation mechanism 64 rotates the first arm 62 about its rotation axis to move the wafer W back and forth horizontally between the transfer position P2 and the turning position P3 along an arc-shaped trajectory. In this case, the movement distance of the wafer W from the transfer position P2 to the turning position P3 (i.e., the length of the arc-shaped trajectory) may be equal to or greater than the diameter of the wafer W.

[0073] After the liquid Q has been removed from the upper surface of the wafer W, the lifting mechanism 67 raises the transfer stage 61 on which the next wafer W is placed. Then, the polishing head 1 holds the wafer W and moves it to a polishing position P1 (see FIG. 12 ) above the polishing pad 2. Thereafter, the polishing head 1 presses the lower surface of the wafer W against the polishing surface 2 a of the polishing pad 2, thereby polishing the lower surface of the wafer W.

[0074] In one embodiment, the polishing head 1 may be cleaned while the polished wafer W released from the polishing head 1 is at the transfer position P2 on the transfer stage 61. In this case, the transfer device 160 may remove the liquid Q from the upper surface of the wafer W by horizontal movement when transferring the polished wafer W to the next polishing device. Cleaning of the polishing head 1 is completed before the next wafer W is transferred to the transfer position P2.

[0075] In this embodiment, the operation control unit 190 also brings the transport device 160 to an emergency stop based on the emergency stop signal. During the emergency stop of the transport device 160, the operation control unit 190 issues a command to the liquid supply nozzle 55 to supply liquid to the surface of the polishing head 1 in order to prevent the surface of the polishing head 1 from drying out. When liquid is supplied to the surface of the polishing head 1 while the wafer W on the transport stage 61 is at the transfer position P2, the liquid supplied to the surface of the polishing head 1 drops onto the wafer W.

[0076] When the wafer W is at the transfer position P2, the operation control unit 190 issues a command to the transport device 160 based on the stop release signal to remove the liquid from the upper surface of the wafer W. The operation control unit 190 also issues a command to the liquid supply nozzle 55 to stop supplying the liquid to the surface of the polishing head 1. The operation of removing the liquid from the upper surface of the wafer W is the same as the operation described with reference to FIG. 13 , so a redundant description will be omitted. After the liquid Q has been removed from the upper surface of the wafer W, the polishing head 1 holds the wafer W and moves the wafer W to the polishing position P1 (see FIG. 12 ) above the polishing pad 2. Thereafter, the polishing head 1 presses the lower surface of the wafer W against the polishing surface 2 a of the polishing pad 2, thereby polishing the lower surface of the wafer W.

[0077] According to this embodiment, even if the liquid supplied to the polishing head 1 falls onto the upper surface of the wafer W during an emergency stop of the transport device 160, the liquid is removed from the upper surface of the wafer W by the transport device 160 before polishing the wafer W. As a result, the polishing head 1 can apply an intended force to the wafer W, and a desired film thickness profile of the wafer W can be achieved.

[0078] After polishing the wafer W, the polishing head 1 moves together with the wafer W to the transfer position P2. Then, the polishing head 1 releases the wafer W and places it on the transfer stage 61 of the transfer device 160. The transfer device 160 moves the wafer W to the next process (e.g., to one of the polishing apparatuses 120B to 120D or one of the cleaning apparatuses 130A and 130B) (see FIG. 1). In one embodiment, the polishing system 100 may include multiple transfer devices 160 arranged along the longitudinal direction of the polishing system 100 (i.e., the direction in which the polishing apparatuses 120A to 120D are aligned), and the wafer W may be moved to the next process via the multiple transfer devices 160.

[0079] Figure 14 is a schematic diagram showing yet another embodiment of a transfer device 160. Details of this embodiment that are not particularly described are the same as those of the embodiment described with reference to Figures 10 to 13, so duplicated descriptions will be omitted. As shown in Figure 14, the transfer device 160 of this embodiment is equipped with a tilting mechanism 69 that tilts the transfer stage 61. The transfer stage 61 is connected to a first arm 62 via the tilting mechanism 69.

[0080] The tilting mechanism 69 has a support shaft 69a extending horizontally and a rotation device 69b that rotates the support shaft 69a. The support shaft 69a is connected to the transfer stage 61, and the rotation device 69b is fixed to the first arm 62. The rotation device 69b is configured to rotate the support shaft 69a and the transfer stage 61 by a predetermined angle. The rotation device 69b is equipped with an actuator (not shown) such as a servo motor. The tilting mechanism 69 (specifically, the rotation device 69b) is electrically connected to the operation control unit 190, and the operation of the tilting mechanism 69 (specifically, the rotation device 69b) is controlled by the operation control unit 190.

[0081] The next wafer W to be polished is placed on the transfer stage 61 and moved together with the transfer stage 61 to a transfer position P2 below the polishing head 1 by the first rotation mechanism 64 and the second rotation mechanism 65. Before holding the next wafer W, the polishing head 1 is cleaned with liquid supplied from the liquid supply nozzle 55. The liquid used to clean the polishing head 1 falls onto the upper surface of the wafer W on the transfer stage 61.

[0082] 15 , the tilting mechanism 69 of the transfer device 160 tilts the transfer stage 61 and the wafer W together before the wafer W is held by the polishing head 1. In one embodiment, the tilt angle θ of the wafer W by the transfer device 160 is 45 degrees or greater. When the wafer W is tilted, the liquid Q spills from the upper surface of the wafer W, and is thereby removed from the upper surface of the wafer W. In one embodiment, with the transfer stage 61 and the wafer W tilted by the tilting mechanism 69, the first rotation mechanism 64 and the second rotation mechanism 65 may move the transfer stage 61 and the wafer W in the horizontal direction.

[0083] After the liquid Q is removed from the upper surface of the wafer W, the tilting mechanism 69 returns the wafer W to a horizontal position. The polishing head 1 holds the wafer W and moves it to a polishing position P1 (see FIG. 12 ) above the polishing pad 2. Thereafter, the polishing head 1 presses the lower surface of the wafer W against the polishing surface 2 a of the polishing pad 2, thereby polishing the lower surface of the wafer W.

[0084] In one embodiment, the polishing head 1 may be cleaned while the polished wafer W released from the polishing head 1 is at the transfer position P2 on the transfer stage 61. In this case, the transfer device 160 may remove the liquid Q from the upper surface of the wafer W by horizontal movement when transferring the polished wafer W to the next polishing device (or by horizontal movement with the transfer stage 61 and the wafer W tilted by the tilting mechanism 69). Cleaning of the polishing head 1 is completed before the next wafer W is transferred to the transfer position P2.

[0085] In this embodiment, the operation control unit 190 also brings the transport device 160 to an emergency stop based on the emergency stop signal. During the emergency stop of the transport device 160, the operation control unit 190 issues a command to the liquid supply nozzle 55 to supply liquid to the surface of the polishing head 1 in order to prevent the surface of the polishing head 1 from drying out. When liquid is supplied to the surface of the polishing head 1 while the wafer W on the transport stage 61 is at the transfer position P2, the liquid supplied to the surface of the polishing head 1 drops onto the wafer W.

[0086] When the wafer W is at the transfer position P2, the operation control unit 190 issues a command to the transport device 160 to remove the liquid from the upper surface of the wafer W based on the stop release signal. The operation control unit 190 also issues a command to the liquid supply nozzle 55 to stop supplying the liquid to the surface of the polishing head 1. The operation of removing the liquid from the upper surface of the wafer W is the same as the operation described with reference to FIG. 15 , so a redundant description will be omitted. After the liquid Q is removed from the upper surface of the wafer W, the tilting mechanism 69 returns the wafer W to a horizontal position. The polishing head 1 holds the wafer W and moves it to the polishing position P1 (see FIG. 12 ) above the polishing pad 2. The polishing head 1 then presses the lower surface of the wafer W against the polishing surface 2 a of the polishing pad 2, thereby polishing the lower surface of the wafer W.

[0087] According to this embodiment, even if the liquid supplied to the polishing head 1 falls onto the upper surface of the wafer W during an emergency stop of the transport device 160, the liquid is removed from the upper surface of the wafer W by the transport device 160 before polishing the wafer W. As a result, the polishing head 1 can apply an intended force to the wafer W, and a desired film thickness profile of the wafer W can be achieved.

[0088] In one embodiment, the operation of removing the liquid supplied during cleaning of the polishing head 1 from the upper surface of the wafer W may be different from the operation of removing the liquid supplied to prevent drying of the polishing head 1 from the upper surface of the wafer W during an emergency stop of the transfer device 160. For example, in the transfer device 160 having the tilting mechanism 57 described with reference to Figures 7 to 9, the operation of removing the liquid supplied during cleaning of the polishing head 1 from the upper surface of the wafer W may be tilting the wafer W by the transfer device 160, and the operation of removing the liquid supplied during cleaning of the polishing head 1 from the upper surface of the wafer W during an emergency stop of the transfer device 160 may be horizontally moving the wafer W by the transfer device 160.

[0089] Fig. 16 is a schematic diagram showing another embodiment of the polishing system 100. The transport device 160 of this embodiment is the transport device 160 described with reference to Figs. 4 to 6, but can also be applied to any of the transport device 160 equipped with the tilting mechanism 57 described with reference to Figs. 7 to 9, the transport device 160 which is a horizontal articulated robot described with reference to Figs. 10 to 13, and the transport device 160 equipped with the tilting mechanism 69 described with reference to Figs. 14 and 15.

[0090] 16 , the polishing system 100 of this embodiment further includes a pusher 70 disposed at a transfer position P2 below the polishing head 1. The pusher 70 includes a stage 71 on which the wafer W is placed and a stage lifting mechanism 72 that moves the stage 71 up and down. The stage lifting mechanism 72 includes an actuator (not shown) such as an air cylinder, but the configuration thereof is not particularly limited. The stage lifting mechanism 72 is electrically connected to an operation control unit 190, and the operation of the stage lifting mechanism 72 is controlled by the operation control unit 190. In one embodiment, the transport device 160 does not need to include the lifting mechanism 52.

[0091] The wafer W to be polished next is transported by the transport device 160 to a transfer position P2 above the stage 71 of the pusher 70. At this time, the transport stage 51 is positioned above the stage 71 at the transfer position P2. When the stage 71 is raised by the stage lifting mechanism 72, the wafer W on the transport stage 51 is placed on the stage 71. Before holding the wafer W, the polishing head 1 is cleaned with liquid supplied from the liquid supply nozzle 55. The liquid used to clean the polishing head 1 falls onto the upper surface of the wafer W on the stage 71.

[0092] The wafer W on the stage 71 is placed again on the transfer stage 51 of the transfer device 160, and as described with reference to Figures 5 and 6, the liquid is removed from the upper surface of the wafer W by horizontal movement by the transfer device 160. Thereafter, the wafer W on the transfer stage 51 is placed again on the stage 71 of the pusher 70.

[0093] In one embodiment, the polishing head 1 may be cleaned before the wafer W to be polished next is transported to the transfer position P2 by the transport device 160. In this case, the wafer W to be polished next is transported to the transfer position P2 above the stage 71 of the pusher 70 by the transport device 160 after the polishing head 1 has been cleaned. Thereafter, when the stage 71 is raised by the stage lifting mechanism 72, the wafer W on the transport stage 51 is placed on the stage 71.

[0094] In one embodiment, the polishing head 1 may be cleaned while the polished wafer W released from the polishing head 1 is at the transfer position P2 on the stage 71. In this case, the transport device 160 that receives the wafer W from the pusher 70 may remove the liquid Q from the upper surface of the wafer W by horizontal movement when transporting the polished wafer W to the next polishing device. Cleaning of the polishing head 1 is completed before the next wafer W is transported to the transfer position P2.

[0095] When the polishing head 1 is at the transfer position P2, the stage lifting mechanism 72 of the pusher 70 lifts the stage 71. The polishing head 1 holds the wafer W on the stage 71 and moves to the polishing position P1 (see FIG. 4) together with the wafer W. Thereafter, the polishing head 1 presses the lower surface of the wafer W against the polishing surface 2 a of the polishing pad 2, thereby polishing the lower surface of the wafer W.

[0096] In this embodiment, the operation control unit 190 also brings the transport device 160 to an emergency stop based on the emergency stop signal. During the emergency stop of the transport device 160, the operation control unit 190 issues a command to the liquid supply nozzle 55 to supply liquid to the surface of the polishing head 1 in order to prevent the surface of the polishing head 1 from drying out. When liquid is supplied to the surface of the polishing head 1 while the wafer W on the stage 71 is at the transfer position P2, the liquid supplied to the surface of the polishing head 1 drops onto the wafer W.

[0097] When the wafer W is at the transfer position P2, the operation control unit 190 issues a command to the transfer device 160 based on the stop release signal to remove the liquid from the upper surface of the wafer W. Specifically, the wafer W on the stage 71 is placed back onto the transfer stage 51 of the transfer device 160, and the liquid is removed from the upper surface of the wafer W by horizontal movement by the transfer device 160. The operation control unit 190 also issues a command to the liquid supply nozzle 55 to stop supplying the liquid to the surface of the polishing head 1. After the liquid Q has been removed from the upper surface of the wafer W, the wafer W is placed back onto the stage 71 of the pusher 70 by the transfer device 160. The polishing head 1 holds the wafer W and moves it to the polishing position P1 (see FIG. 4) above the polishing pad 2. The polishing head 1 then presses the lower surface of the wafer W against the polishing surface 2a of the polishing pad 2, thereby polishing the lower surface of the wafer W.

[0098] According to this embodiment, even if the liquid supplied to the polishing head 1 falls onto the upper surface of the wafer W during an emergency stop of the transport device 160, the liquid is removed from the upper surface of the wafer W by the transport device 160 before polishing the wafer W. As a result, the polishing head 1 can apply an intended force to the wafer W, and a desired film thickness profile of the wafer W can be achieved.

[0099] The above-described embodiments have been described for the purpose of enabling a person of ordinary skill in the art to practice the present invention. Various modifications of the above-described embodiments would be obvious to a person skilled in the art, and the technical concept of the present invention may be applied to other embodiments. Therefore, the present invention is not limited to the described embodiments, but is to be interpreted in the broadest scope in accordance with the technical concept defined by the claims.

[0100] The present invention can be used in techniques for removing liquid from the top surface of a wafer before the wafer is polished.

[0101] REFERENCE SIGNS LIST 1 Polishing head 2 Polishing pad 2a Polishing surface 3 Polishing table 5 Polishing liquid supply nozzle 6 Table motor 11 Polishing head shaft 15 Head arm 16 Support shaft 25A, 25B, 25C, 25D, 25E ​​Pressure chamber 31 Carrier 32 Retainer ring 34 Elastic membrane 35 Contact portion 35a Contact surface 36a, 36b, 36c Inner wall portion 36d Outer wall portion 37 Membrane (rolling diaphragm) 40 Rotary joint 51 Transport stage 52 Lifting mechanism 53 Horizontal movement mechanism 55 Liquid supply nozzle 57 Tilting mechanism 61 Transport stage 62 First arm 63 Second arm 64 First rotation mechanism (first joint) 65 Second rotation mechanism (second joint) 67 Lifting mechanism 69 Tilting mechanism 70 Pusher 71 Stage 72 Stage lifting mechanism 100 Polishing system 110 Load port 120A, 120B, 120C, 120D Polishing device 130A, 130B Cleaning device 140 Drying device 150, 160, 170, 180 Transfer device 190 Operation control unit 190a Storage device 190b Arithmetic unit F1, F2, F3, F4, F5 Gas transfer line R1, R2, R3, R4, R5 Pressure regulator L1, L2, L3, L4, L5 Vacuum line V1, V2, V3, V4, V5 Vacuum valve

Claims

1. A polishing method comprising: bringing a transport device that transports a workpiece to a polishing device to an emergency stop based on an emergency stop signal; supplying a liquid to the surface of a polishing head of the polishing device that is in a transfer position while the transport device is in the emergency stop state; removing the liquid from the upper surface of the workpiece by the transport device based on a stop release signal when the workpiece is in the transfer position below the polishing head; then holding the workpiece in the transfer position with the polishing head; and pressing the lower surface of the workpiece against a polishing surface with the polishing head to polish the lower surface of the workpiece.

2. The polishing method of claim 1, wherein removing the liquid from the top surface of the workpiece by the conveying device comprises removing the liquid from the top surface of the workpiece by moving the workpiece horizontally by the conveying device.

3. The polishing method according to claim 2, wherein the horizontal movement distance of the workpiece by the transport device is equal to or greater than the diameter of the workpiece.

4. The polishing method of claim 1, wherein removing the liquid from the upper surface of the workpiece by the transport device comprises removing the liquid from the upper surface of the workpiece by tilting the workpiece by the transport device.

5. The polishing method according to claim 4, wherein the tilt angle of the workpiece caused by the conveying device is 45 degrees or more.

6. The polishing method according to claim 1, wherein the transport device is a linear-motion transport device equipped with a horizontal linear motion mechanism that moves the workpiece along an X-axis extending horizontally.

7. The polishing method according to claim 1, wherein the transport device is a horizontal articulated robot.

8. A polishing system comprising: a polishing apparatus for polishing a workpiece; a transport apparatus for transporting the workpiece to the polishing apparatus; and an operation control unit for controlling the operation of the polishing apparatus and the transport apparatus, wherein the polishing apparatus comprises a polishing head for pressing the workpiece against a polishing surface; and a liquid supply nozzle for supplying liquid to a surface of the polishing head, wherein the operation control unit is configured to: bring the transport apparatus to an emergency stop based on an emergency stop signal; during the emergency stop of the transport apparatus, issue a command to the liquid supply nozzle to supply the liquid to the surface of the polishing head at a transfer position; when the workpiece is at the transfer position below the polishing head, issue a command to the transport apparatus based on a stop release signal to remove the liquid from the upper surface of the workpiece, and then issue a command to the polishing head to hold the workpiece at the transfer position; and issue a command to the polishing head to press the lower surface of the workpiece against the polishing surface to polish the lower surface of the workpiece.

9. The polishing system described in claim 8, wherein the transport device comprises a transport stage on which the workpiece is placed and a horizontal movement mechanism for moving the transport stage horizontally, and the operation control unit is configured to issue a command to the horizontal movement mechanism to move the transport stage horizontally, thereby removing the liquid from the top surface of the workpiece.

10. The polishing system according to claim 9, wherein the distance of horizontal movement of the workpiece by the transport device is equal to or greater than the diameter of the workpiece.

11. The polishing system described in claim 8, wherein the transport device comprises a transport stage on which the workpiece is placed and a tilting mechanism for tilting the transport stage, and the operation control unit is configured to issue a command to the tilting mechanism to tilt the transport stage and thereby remove the liquid from the upper surface of the workpiece.

12. The polishing system according to claim 11, wherein the tilt angle of the workpiece caused by the transport device is 45 degrees or more.

13. The polishing system according to claim 8, wherein the transport device is a linear transport device that moves the workpiece along an X-axis extending horizontally.

14. The polishing system according to claim 8, wherein the transport device is a horizontal articulated robot.

Images