Substrate processing apparatus and abnormality determination method

Abstract

To determine abnormalities in a transfer of substrates from a substrate holding device to a transfer stage for the substrate polishing process.SOLUTION: A substrate processing apparatus comprises an abnormality determination section that determines abnormalities in the transfer of substrates from a substrate holding device to a transfer stage based on time difference between a first timing when a first sensor detects that the substrate has been placed on the placing surface of the transfer stage and a second timing when a second sensor detects that the substrate has been placed on the placing surface.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to a substrate processing apparatus and an abnormality determination method. [Background technology]

[0002] In the manufacture of semiconductor devices, chemical mechanical polishing (CMP) equipment is used to planarize the surface of a substrate. Substrates used in the manufacture of semiconductor devices are often disk-shaped. In addition, there is an increasing demand for flatness when planarizing the surfaces of rectangular substrates such as copper clad laminate (CCL) substrates, printed circuit board (PCB) substrates, photomask substrates, and display panels, in addition to semiconductor devices. There is also an increasing demand for planarizing the surfaces of package substrates on which electronic devices are mounted, such as PCB substrates.

[0003] In such substrate processing apparatus, a substrate holding device using an elastic membrane is used to equalize or adjust the relative pressing force between the substrate and the polishing surface of the polishing pad during polishing. As an example, a pressure chamber formed of an elastic membrane is provided under a top ring serving as a substrate holding device, and a gas such as air is supplied to this pressure chamber to press the substrate against the polishing surface of the polishing pad, thereby polishing the substrate.

[0004] After the polishing process is completed, the substrate holding device moves to a position above the transfer stage while holding the substrate, and transfers the substrate to the transfer stage. As an example, the transfer of the substrate is performed by supplying gas to a pressure chamber and injecting gas into a gap between the substrate and the elastic membrane, thereby releasing the substrate from the elastic membrane. The placement of the substrate on the transfer stage is detected by a plurality of sensors for detecting different positions of the substrate. The substrate placed on the transfer stage is transferred to a swing transporter and transported to the subsequent process. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2012-178608 A Summary of the Invention [Problem to be solved by the invention]

[0006] In the above-mentioned substrate processing apparatus, damage or breakage of the substrate may be detected in the swing transporter. Since the swing transporter transports the substrate through a plurality of processing steps, if damage or breakage of the substrate is detected in the swing transporter, confirmation is performed in each of the plurality of processing steps, which may make the maintenance process complicated. Here, such damage or breakage of the substrate may occur when the substrate is transferred from the substrate holding device to the transfer stage. Research by the present inventors has revealed that, particularly when the elastic membrane of the substrate holding device deteriorates, the substrate may not be released smoothly from the elastic membrane and may be released at an angle, resulting in damage or breakage of the substrate.

[0007] The present invention has been made in consideration of the above-mentioned problems, and one of its objects is to propose a substrate processing apparatus and an abnormality determination method that can determine abnormalities in the transfer of a substrate from a substrate holding device to a transport stage for substrate polishing processing. [Means for solving the problem]

[0008] According to one embodiment of the present invention, there is provided a substrate processing apparatus for performing a polishing process on a surface to be polished of a substrate, the substrate processing apparatus comprising a polishing table for supporting a polishing pad, a substrate holding surface formed of an elastic film, and a pressure chamber, the substrate being held on the substrate holding surface and the substrate being polished by the pressure in the pressure chamber. A substrate processing apparatus is proposed, comprising: a substrate holding device configured to press a substrate against the polishing pad; a transport stage having a loading surface on which the substrate is to be placed and configured to transfer the substrate from the substrate holding device to the loading surface by a substrate removal operation by the substrate holding device; a plurality of sensors including a first sensor and a second sensor configured to detect different portions of the substrate for detecting that the substrate has been placed on the loading surface; and an abnormality determination unit that determines an abnormality in the transfer of the substrate from the substrate holding device to the transport stage based on the time difference between a first timing at which the first sensor detects that the substrate has been placed on the loading surface and a second timing at which the second sensor detects that the substrate has been placed on the loading surface.

[0009] According to one embodiment of the present invention, there is proposed an abnormality determination method for determining abnormality in substrate transfer in a substrate processing apparatus, the substrate processing apparatus comprising: a polishing table for supporting a polishing pad; a substrate holding device having a substrate holding surface composed of an elastic membrane and a pressure chamber, and configured to hold the substrate on the substrate holding surface and press the substrate against the polishing pad by the pressure in the pressure chamber; and a transport stage having a loading surface for loading the substrate and configured to transfer the substrate from the substrate holding device to the loading surface by a substrate removal operation by the substrate holding device, the abnormality determination method including, when it is determined that the substrate has been loaded on the loading surface, determining abnormality in the transfer of the substrate from the substrate holding device to the transport stage based on the time difference between a first timing at which it is detected that a first portion of the substrate has been loaded on the loading surface and a second timing at which it is detected that a second portion of the substrate different from the first portion has been loaded on the loading surface. [Brief description of the drawings]

[0010] [Figure 1] 1 is a plan view showing an overall configuration of a substrate processing apparatus according to an embodiment of the present invention; [Diagram 2] 2 is a schematic diagram showing a configuration of a polishing module according to the embodiment; [Diagram 3] 2 is a schematic cross-sectional view of a top ring constituting a substrate holding device that holds a wafer, which is an object to be polished, and presses it against a polishing surface on a polishing table. [Figure 4] 2 is a schematic view showing the substrate transfer device from above; FIG. [Figure 5A] 1 is a schematic view showing a process of transferring a wafer from a top ring to a substrate transfer device; [Figure 5B] 1 is a schematic view showing a process of transferring a wafer from a top ring to a substrate transfer device; [Figure 5C] 1 is a schematic view showing a process of transferring a wafer from a top ring to a substrate transfer device; [Figure 6] 11 is a flowchart showing an example of wafer transfer abnormality determination by a controller. [Figure 7] 4 is a time chart showing an example of detection signals of each sensor in a normal state. [Figure 8] 5 is a time chart showing an example of detection signals of the sensors in an abnormal state. [Figure 9] FIG. 13 is a diagram showing an example of a time difference in the seating timing of each wafer. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, embodiments of a substrate processing apparatus and an abnormality determination method according to the present invention will be described with reference to the accompanying drawings. In the accompanying drawings, identical or similar elements are given identical or similar reference symbols, and duplicated descriptions of identical or similar elements may be omitted in the description of each embodiment. Furthermore, features shown in each embodiment can be applied to other embodiments as long as they are not mutually inconsistent.

[0012] 1 is a plan view showing an overall configuration of a substrate processing apparatus according to an embodiment of the present invention. As shown in FIG. 1, the substrate processing apparatus includes a substantially rectangular housing 1. The interior is partitioned by partitions 1a and 1b into a load port 2, a polishing module 3, and a cleaning module 4. The load port 2, the polishing module 3, and the cleaning module 4 are assembled independently and evacuated independently. The substrate processing apparatus also has a controller 5 that controls the substrate processing operation.

[0013] The load port 2 is equipped with two or more (four in this embodiment) front load units 20 on which wafer cassettes for stocking a large number of wafers (an example of substrates) are placed. These front load units 20 are disposed adjacent to the housing 1 and are arranged along the width direction (direction perpendicular to the longitudinal direction) of the substrate processing apparatus. The front load units 20 are capable of mounting an open cassette, a Standard Manufacturing Interface (SMIF) pod, or a Front Opening Unified Pod (FOUP). Note that, in this embodiment, a circular semiconductor wafer is used as an example of a substrate, but the substrate is not limited to this example, and for example, a rectangular substrate may be used.

[0014] The load port 2 is also provided with a travel mechanism 21 that extends along the arrangement of the front load sections 20. A transfer robot (loader) 22 that is movable along the arrangement direction of the wafer cassettes is installed on this travel mechanism 21. The transfer robot 22 is capable of accessing the wafer cassettes mounted on the front load section 20 by moving on the travel mechanism 21. In this embodiment, the transfer robot 22 has two hands, one above the other. As an example, the transfer robot 22 uses the upper hand when returning a processed wafer to the wafer cassette, and uses the lower hand when removing an unprocessed wafer from the wafer cassette.

[0015] The load port 2 is a clean area, and the inside of the load port 2 is maintained at a higher pressure than the outside of the substrate processing apparatus, the polishing module 3, and the cleaning module 4. The polishing module 3 is a dirty area because it uses slurry as the polishing liquid. A negative pressure is generated inside the polishing module 3, and the pressure is maintained lower than the internal pressure of the cleaning module 4.

[0016] The polishing module 3 is an area where the wafer is polished (flattened), and includes a first polishing module 3A, a second polishing module 3B, a third polishing module 3C, and a fourth polishing module 3D. As shown in FIG. 1, in this embodiment, the first polishing module 3A, the second polishing module 3B, the third polishing module 3C, and the fourth polishing module 3D are arranged along the longitudinal direction of the substrate processing apparatus. Note that one, two, three, or five or more polishing modules may be provided. The first polishing module 3A, the second polishing module 3B, the third polishing module 3C, and the fourth polishing module 3D have the same configuration, so only the first polishing module 3A will be described below.

[0017] The first polishing module 3A includes a polishing table 30 on which a polishing pad 10 having a polishing surface is attached, and a top ring (substrate holding device) 31 for holding a wafer and polishing the wafer while pressing it against the polishing pad 10 on the polishing table 30. The first polishing module 3A also includes a polishing liquid supply nozzle 32 for supplying a polishing liquid or a dressing liquid (e.g., pure water) to the polishing pad 10, a dresser 33 for dressing the polishing surface of the polishing pad 10, and an atomizer 34 for spraying a mixed fluid of a liquid (e.g., pure water) and a gas (e.g., nitrogen gas) or a liquid (e.g., pure water) in a mist onto the polishing surface.

[0018] Next, a transfer mechanism for transferring a wafer will be described. As shown in FIG. 1, a first linear transporter 6 is disposed adjacent to the first polishing module 3A and the second polishing module 3B. The first linear transporter 6 has four transfer positions (in order from the load port side) along the direction in which the first polishing module 3A and the second polishing module 3B are arranged. TP1, TP2, TP3, and TP4 (hereinafter referred to as a first transfer position TP1, a second transfer position TP2, a third transfer position TP3, and a fourth transfer position TP4).

[0019] A second linear transporter 7 is disposed adjacent to the third polishing module 3C and the fourth polishing module 3D. The second linear transporter 7 is a mechanism for transporting wafers between three transfer positions (the fifth transfer position TP5, the sixth transfer position TP6, and the seventh transfer position TP7, in that order from the load port side) along the direction in which the third polishing module 3C and the fourth polishing module 3D are arranged.

[0020] The wafer is transported to the first polishing module 3A and the second polishing module 3B by the first linear transporter 6. The top ring 31 of the first polishing module 3A moves between the polishing position and the second transfer position TP2 by the swinging motion of the top ring head. The wafer is transferred to the top ring 31 at the second transfer position TP2. Similarly, the top ring 31 of the second polishing module 3B moves between the polishing position and the third transfer position TP3, and the wafer is transferred to the top ring 31 at the third transfer position TP3. The top ring 31 of the third polishing module 3C moves between the polishing position and the sixth transfer position TP6, and the wafer is transferred to the top ring 31 at the sixth transfer position TP6. The top ring 31 of the fourth polishing module 3D moves between the polishing position and the seventh transfer position TP7, and the wafer is transferred to the top ring 31 at the seventh transfer position TP7.

[0021] At the first transfer position TP1, a lifter 11 for receiving a wafer from the transfer robot 22 is disposed. The wafer is delivered from the transfer robot 22 to the first linear transporter 6 via the lifter 11. A shutter (not shown) is provided on the partition wall 1a between the lifter 11 and the transfer robot 22, and the shutter is opened during the transfer of the wafer so that the wafer is delivered from the transfer robot 22 to the lifter 11. A swing transporter 12 is disposed between the first linear transporter 6, the second linear transporter 7, and the cleaning module 4. The swing transporter 12 has a hand that can move between the fourth transfer position TP4 and the fifth transfer position TP5, and the transfer of the wafer from the first linear transporter 6 to the second linear transporter 7 is performed by the swing transporter 12. The wafer is transported to the third polishing module 3C and / or the fourth polishing module 3D by the second linear transporter 7. Furthermore, the wafer polished in the polishing module 3 is transported to the cleaning module 4 via the swing transporter 12 .

[0022] FIG. 2 is a schematic diagram showing the configuration of a first polishing module 3A according to this embodiment. As shown in FIG. 2, the first polishing module 3A includes a polishing table 30 and a top ring 31 that holds a substrate such as a wafer as an object to be polished and presses it against a polishing surface on the polishing table. The polishing table 30 is connected to a motor (not shown) disposed below the table shaft 30A via the table shaft 30A and is rotatable about the table shaft 30A. A polishing pad 10 is attached to the upper surface of the polishing table 30, and a polishing surface 10a of the polishing pad 10 constitutes a polishing surface for polishing a wafer W. A polishing liquid supply nozzle 32 is installed above the polishing table 30, and a polishing liquid Q is supplied onto the polishing pad 10 on the polishing table 30 by the polishing liquid supply nozzle 32.

[0023] The top ring 31 includes a top ring body 202 that presses the wafer W against the polishing surface 10a, and a retainer ring 203 that holds the outer periphery of the wafer W to prevent the wafer W from jumping out of the top ring.

[0024] The top ring 31 is connected to a top ring shaft 111, and the top ring shaft 111 is moved up and down relative to the top ring head 110 by a vertical movement mechanism 124. By the vertical movement of the top ring shaft 111, the entire top ring 31 is raised and lowered relative to the top ring head 110 so as to be positioned.

[0025] The up-and-down movement mechanism 124, which moves the top ring shaft 111 and the top ring 31 up and down, includes a bridge 128 that rotatably supports the top ring shaft 111 via a bearing 126, a ball screw 132 attached to the bridge 128, a support base 129 supported by a support column 130, and a servo motor 138 provided on the support base 129.

[0026] The ball screw 132 includes a screw shaft 132a connected to a servo motor 138, and a nut 132b into which the screw shaft 132a is screwed. The top ring shaft 111 moves up and down together with the bridge 128. Therefore, when the servo motor 138 is driven, the bridge 128 moves up and down via the ball screw 132, and as a result, the top ring shaft 111 and the top ring 31 move up and down.

[0027] The top ring shaft 111 is connected to the rotating cylinder 112 via a key (not shown). The rotating cylinder 112 is provided with a timing pulley 113 on its outer periphery. A top ring rotating motor 114 is fixed to the top ring head 110, and the timing pulley 113 is connected to a timing pulley 116 provided on the top ring rotating motor 114 via a timing belt 115. Therefore, by driving the top ring rotating motor 114 to rotate, the rotating cylinder 112 and the top ring shaft 111 rotate together via the timing pulley 116, the timing belt 115, and the timing pulley 113, and the top ring 31 rotates. The top ring rotating motor 114 is provided with an encoder 140. The encoder 140 has a function of detecting the rotation angle position of the top ring 31 and a function of accumulating the number of rotations of the top ring 31. A sensor for detecting the rotation angle "reference position (0 degrees)" of the top ring 31 may be provided separately. The top ring head 110 is supported by a top ring head shaft 117 which is rotatably supported by a frame (not shown). The top ring rotary motor 114, the servo motor 138, the encoder 140 and other devices in the apparatus are controlled by a controller 5.

[0028] In the first polishing module 3A configured as shown in FIG. 2, the top ring 31 is configured to hold a substrate such as a wafer W on its lower surface. The top ring head 110 is configured to be rotatable about a top ring head shaft 117, and the top ring 31 holding the wafer W on its lower surface is moved from a receiving position of the wafer W to above the polishing table 30 by the rotation of the top ring head 110. Then, the top ring 31 is lowered to press the wafer W against the surface (polishing surface) 10a of the polishing pad 10. At this time, the top ring 31 and the polishing table 30 are rotated, and a polishing liquid is supplied onto the polishing pad 10 from a polishing liquid supply nozzle 32 provided above the polishing table 30. In this manner, the wafer W is brought into sliding contact with the polishing surface 10a of the polishing pad 10 to polish the surface of the wafer W.

[0029] Next, the top ring (substrate holding device) 31 will be described in more detail. Fig. 3 is a schematic cross-sectional view of the top ring 31 constituting a substrate holding device that holds a wafer W, which is an object to be polished, and presses it against a polishing surface on a polishing table. Fig. 3 shows only the main components constituting the top ring 31.

[0030] As shown in Fig. 3, the top ring 31 includes a top ring body 202 that presses the wafer W against the polishing surface 10a, and a retainer ring 203 that directly presses the polishing surface 10a. The top ring body 202 is made of a roughly disk-shaped member, and the retainer ring 203 is attached to the outer periphery of the top ring body 202. The top ring body 202 is The top ring body 202 is formed of a resin such as a ging plastic (e.g., PEEK). A membrane (elastic membrane) 204 that comes into contact with the back surface of the wafer is attached to the bottom surface of the top ring body 202. The membrane 204 defines a pressure chamber, and its bottom surface defines a substrate holding surface that comes into contact with the wafer W. The membrane 204 is formed of a rubber material that has excellent strength and durability, such as ethylene propylene rubber (EPDM), polyurethane rubber, or silicone rubber.

[0031] 3, the membrane 204 has a plurality of concentric partition walls 204a, and these partition walls 204a form a circular center chamber 205, an annular ripple chamber 206, an annular outer chamber 207, and an annular edge chamber 208 between the upper surface of the elastic membrane 204 and the lower surface of the top ring body 202. That is, the center chamber 205 is formed in the center of the top ring body 202, and the ripple chamber 206, the outer chamber 207, and the edge chamber 208 are formed concentrically in this order from the center toward the outer periphery. The membrane 204 has a plurality of holes 204h in the ripple area (ripple chamber 206) that penetrate the elastic membrane for suctioning a wafer in the thickness direction. In the example shown in FIG. 3, the holes 204h are provided in the ripple area, but they may be provided outside the ripple area. In addition, in the example shown in FIG. 3, the membrane 204 has a plurality of concentric partition walls 204a, but is not limited to this example, and the partition walls may be provided so as to divide the membrane into a plurality of regions in the circumferential direction, or the membrane 204a may not be provided.

[0032] A flow passage 211 communicating with the center chamber 205, a flow passage 212 communicating with the ripple chamber 206, a flow passage 213 communicating with the outer chamber 207, and a flow passage 214 communicating with the edge chamber 208 are formed in the top ring body 202. Each of the flow passages 211 to 214 is connected via a rotary joint 225 to flow passages 221 to 224 which are connected to a vacuum source and a pressure adjustment unit (not shown).

[0033] A retainer ring pressurizing chamber 209 made of an elastic membrane is also formed directly above the retainer ring 203, and the retainer ring pressurizing chamber 209 is connected to a flow path 226 via a flow path 215 and a rotary joint 225 formed in the top ring body (carrier) 202. The flow path 226 is then connected to a vacuum source and a pressure adjusting unit (not shown).

[0034] In this top ring 31, the vacuum source and the pressure adjustment unit can independently adjust the pressure inside the center chamber 205, the ripple chamber 206, the outer chamber 207, the edge chamber 208, and the retaining ring pressurizing chamber 209. With this structure, the pressing force with which the wafer W is pressed against the polishing pad 10 can be adjusted for each area of ​​the wafer W, and the pressing force with which the retaining ring 203 presses against the polishing pad 10 can be adjusted.

[0035] A series of polishing steps by the substrate processing apparatus configured as shown in FIGS. 1 to 3 will be described. The top ring 31 receives the wafer W from the first linear transporter 6 and holds it by vacuum suction. The membrane 204 has a plurality of holes 204h for vacuum suction of the wafer W, and these holes 204h are connected to a vacuum source (not shown). The top ring 31 holding the wafer W by vacuum suction is lowered to a preset position for polishing of the top ring. At this position for polishing, the retainer ring 203 is in contact with the surface (polishing surface) 10a of the polishing pad 10. However, since the top ring 31 holds the wafer W by suction before polishing, there is a slight gap (for example, about 1 mm) between the lower surface (surface to be polished) of the wafer W and the surface (polishing surface) 10a of the polishing pad 10. Then, both the polishing table 30 and the top ring 31 are rotated. In this state, the membrane 204 on the back side of the wafer W is inflated, the bottom surface of the wafer (surface to be polished) is brought into contact with the surface (polishing surface) of the polishing pad 10, and the polishing table 30 and the top ring 31 are moved relative to each other, so that the surface (polishing surface) of the wafer W is polished until it reaches a predetermined state (for example, a predetermined film thickness). .

[0036] After the wafer processing step on the polishing pad 10 is completed, the wafer W is attracted to the top ring 31, the top ring 31 is raised, and the wafer W is moved to a substrate transfer device 800 possessed by the first linear transporter 6 to be released. In this embodiment, the first linear transporter 6, the second linear transporter 7, or the substrate transfer device 800 possessed by them, which release the wafer W, are examples of a "transfer stage".

[0037] Fig. 4 is a schematic view showing the substrate transfer device 800 from above, and Figs. 5A to 5C are schematic views showing the process of transferring a wafer W from the top ring 31 to the substrate transfer device 800. The substrate transfer device 800 has a mounting surface 820 for mounting the wafer W. The substrate transfer device 800 also has push-up pins 801 that push up the retainer ring 203 of the top ring 31. The mounting surface 820 and the push-up pins 801 are each configured to be able to move up and down by a power source (not shown) such as an air cylinder.

[0038] The substrate transfer device 800 of this embodiment also includes three sensors 811-813 for detecting that the wafer W has been transferred from the top ring 31 to the mounting surface 820 (substrate transfer device 800). The sensors 811-813 are arranged spaced apart in the circumferential direction of the wafer W so as to detect different portions of the wafer W from each other. Detection signals from the sensors 811-813 are input to the controller 5. The substrate transfer device 800 preferably includes at least two sensors for detecting that the wafer W has been transferred, and may include four or more sensors.

[0039] As shown in Fig. 5A, the sensor 811 includes, as an example, a light projecting unit 815 and a light receiving unit 816. Although the sensors 812 and 813 are not shown in Figs. 5A to 5C, the sensors 812 and 813 have the same configuration as the sensor 811. The light projecting unit 815 is, for example, a fiber sensor in which a flexible optical fiber cable is used for the light projecting unit of a photoelectron sensor and the detection head is miniaturized. The light receiving unit 816 is, for example, a fiber sensor in which a flexible optical fiber cable is used for the light receiving unit of a photoelectron sensor and the detection head is miniaturized.

[0040] The light-projecting unit 815 projects light in the direction of an arrow A1 (see FIG. 5A). When the wafer W is not peeled off from the top ring 31, the light-receiving unit 816 can receive the light projected from the light-projecting unit 815. On the other hand, when the wafer W is released from the top ring 31 and transferred to the mounting surface 820 as shown in FIG. 5C, the light projected from the light-projecting unit 815 is blocked by the wafer W, and the light-receiving unit 816 cannot detect the light. The controller 5 regards, for example, the time when the light-receiving unit 816 cannot detect light or the light intensity detected by the light-receiving unit 816 falls below a threshold as the time when the wafer W is detected. The light source of the light-projecting unit 815 may be, for example, an LED, and the color of the light may be any color (for example, red, blue, green, white, etc.).

[0041] Furthermore, the substrate transfer apparatus 800 of this embodiment has, for example, three release nozzles 802 facing inward (toward the wafer W) (see FIGS. 5A to 5C). The release nozzles 802 are connected to a pressurized fluid supply source (not shown), and the ejection of the pressurized fluid is controlled by the controller 5. However, the substrate transfer apparatus 800 may have one, two, four or more release nozzles, or may not have a release nozzle.

[0042] Hereinafter, an operation of transferring the wafer W from the top ring 31 to the mounting surface 820 will be described. After the wafer processing process on the polishing pad 10 is completed, the top ring 31 moves to the substrate transfer device 800 while adsorbing the wafer W (see FIG. 5A), and releases the wafer W. After moving to the substrate transfer device 800, the wafer W adsorbed and held by the top ring 31 is released. The cleaning operation may be performed by rotating the top ring 31 while supplying pure water or a chemical solution to the substrate.

[0043] After the top ring 31 moves to the substrate transfer device 800, the top ring 31 descends and the mounting surface 820 rises. As a result, the mounting surface 820 approaches the underside of the wafer W, but the two do not come into contact with each other. Furthermore, as the top ring 31 descends, the push-up pins 801 push up the retainer ring 203 (see FIG. 5B). In this state, the ripple chamber 206 of the membrane 204 is inflated and the vacuum suction of the wafer W is stopped, and the wafer is released. At this time, a pressurized fluid may be sprayed from the release nozzle 802 toward the gap between the membrane 204 and the wafer W. At least one of a pressurized gas (e.g., pressurized nitrogen) and a pressurized liquid (e.g., pure water) may be used as the pressurized fluid.

[0044] When the wafer W is placed on the mounting surface 820, the sensors 811-813 detect the wafer W. When the wafer W is detected by all of the sensors 811-812, the controller 5 determines that the transfer of the wafer W from the top ring 31 to the mounting surface 820 is complete. Thereafter, the mounting surface 820 on which the wafer W is placed is lowered, and the top ring 31 is raised, completing the transfer of the wafer W (see FIG. 5C).

[0045] Next, a description will be given of a determination by the controller 5 of an abnormality in the transfer of the wafer W from the top ring 31 to the mounting surface 820. In this embodiment, the controller 5 corresponds to an example of an "abnormality determination unit". The controller 5 may be configured as a microcomputer having a CPU, a memory, etc., and implementing a predetermined function using software, or may be configured as a hardware circuit performing dedicated arithmetic processing. The controller 5 is not limited to being configured as a single device, and may be configured as a plurality of devices provided separately from each other, for example. FIG. 6 is a flow chart showing an example of an abnormality determination of the transfer of the wafer W by the controller 5. The abnormality determination shown in FIG. 6 is performed, for example, when the polishing process of the wafer W is completed and the wafer W is transferred from the top ring 31 to the mounting surface 820 of the substrate transfer device 800.

[0046] First, the controller 5 moves the top ring 31 holding the wafer W to the substrate transfer device 800 in order to transfer the wafer W from the top ring 31 to the mounting surface 820 (step S10). As a result, the wafer W is placed on the mounting surface 820 as shown in FIG. 5A. The controller 5 determines whether or not the required time for the desorption operation of the wafer W has elapsed (step S12). At this point, the desorption operation of the wafer W has not started, and it is determined that the required time has not elapsed (S12: No), and the process proceeds to the next step (step S14). The process of step S12 will be described in detail later.

[0047] Next, the controller 5 executes an operation to release the wafer W from the top ring 31 (step S14). As a result, the top ring 31 and the substrate transfer device 800 are brought closer to each other, as shown in Fig. 5B. As described above, the membrane 204 is inflated, the vacuum suction of the wafer W is stopped, and the pressurized fluid is sprayed from the release nozzle 802.

[0048] The controller 5 determines whether the wafer W is detected by the sensors 811-813 (steps S15, S16). Because the wafer W has rigidity and may bounce slightly when released from the mounting surface 820, and in order to prevent erroneous detection by the sensors 811-813, it is preferable that the controller 5 determines that the wafer W is detected by the sensor 811 (812, 813) when the wafer W is continuously detected for a predetermined time (e.g., one second).

[0049] When the wafer W is not detected by the sensors 811 to 813, the controller 5 If the determination is affirmative (S15, S16: No), the process returns to step S12, and the wafer W is removed until the required time has elapsed (S12, S14). The required time is longer than the time required for the wafer W to be removed under normal conditions, and may be a predetermined time or a time set by an external input or the like. When the controller 5 determines that the required time has elapsed since the top ring 31 was moved to the substrate transfer device 800 (S12: Yes), the controller 5 determines that the wafer W cannot be transferred from the top ring 31 to the mounting surface 820 (step S22), and ends this process. That is, when the wafer W is not detected by the sensors 811-813 even after the required time has elapsed despite the wafer W being removed, the controller 5 determines that the wafer W cannot be transferred. In this case, the controller 5 may use a display device, a lamp, a buzzer, or the like (not shown) to notify that the wafer W cannot be transferred from the top ring 31 to the mounting surface 820. Instead of or in addition to the process of step S12, when the sensors 811-813 do not detect the wafer W even after the desorption operation process of the wafer W is performed a predetermined number of times (e.g., three times) or more, the controller 5 may determine that the wafer W cannot be transferred from the top ring 31 to the mounting surface 820. In this case, the number of desorption operation processes of the wafer W may be calculated based on, for example, the number of times the membrane 204 is inflated or the number of times the pressurized fluid is ejected from the release nozzle 802.

[0050] Furthermore, when the wafer W is detected by some of the sensors (e.g., sensor 811) but not by the remaining sensors (e.g., sensors 812, 813) for a predetermined determination time (e.g., 2 seconds) (S15: Yes), the controller 5 may determine that the wafer W is placed on the placement surface 820 in an inclined state (step S22) and end the process. At this time, the controller 5 may use a display device, lamp, buzzer, or the like (not shown) to notify that the wafer W is placed on the placement surface 820 in an inclined state.

[0051] When the wafer W is detected by all the sensors 811-813 (S16: Yes), the controller 5 calculates the time difference Δt between the seating timings detected by each sensor (step S18). Note that when the wafer W is detected by all the sensors 811-813, the controller 5 may stop light projection from the light projecting units 815 of the multiple sensors 811-813. In this way, the time during which the wafer W is irradiated with light by the multiple sensors 811-813 can be shortened.

[0052] In the process of step S18, for example, the sensor (e.g., sensor 813) that detects the wafer W earliest among the multiple sensors 811-813 may be set as the first sensor, and the sensor (e.g., sensor 811) that detects the wafer W latest may be set as the second sensor, and the time difference Δt between the seating timings may be calculated. Then, the controller 5 compares the calculated time difference Δt with a predetermined abnormality determination time tref (step S20) to determine whether the wafer W has been normally delivered. Here, the abnormality determination time tref is a time (e.g., 0.5 seconds) for determining whether there is a possibility that an abnormality has occurred in the wafer W due to the release operation, and may be a time that is determined in advance or a time that is set by an external input or the like. Note that the seating timings determined by the multiple sensors 811-813 may be obtained by referring to the time from when the pressurized fluid is ejected from the release nozzle 802 to when the light projection from the light projection units 815 of the multiple sensors 811-813 is stopped.

[0053] FIG. 7 is a time chart showing an example of the detection signals of the sensors in a normal state. FIG. 7 shows detection signals Sg1 to Sg3 from the sensors 811 to 813. In this embodiment, the detection signals Sg1 to Sg3 are "OFF" when the sensors 811 to 813 are not detecting the wafer W, and are "ON" when the sensors 811 to 813 are detecting the wafer W. Note that in FIG. 7 and FIG. 8, the detection signals Sg1 to Sg3 from all the sensors 811 to 813 are "OFF" when the wafer W is not detected, and are "ON" when the sensors 811 to 813 are detecting the wafer W. When the wafer W is detected by the light-projecting unit 815, the light projection from the light-projecting unit 815 is stopped, and the detection signals Sg1 to Sg3 are "OFF". As shown in the figure, in a normal transfer of the wafer W, the detection signals Sg1 to Sg3 are "ON" at almost the same timings t1 to t3 after the time t0 when the de-mounting operation of the wafer W is started. As described above, it is preferable that the controller 5 determines that the seating of the wafer W is detected when the wafer W is continuously detected for a predetermined time (for example, 1 second) (when the "ON" signal continues), and obtains the timing at which the signal becomes "ON" as the timing (also referred to as "seating timing") t1 to t3. In the example shown in FIG. 7, the time difference Δt between the timing t3 and the timing t1 is less than the abnormality determination time tref (S20: Yes), and the controller 5 determines that the de-mounting operation of the wafer W has been performed normally (step S24), and ends the process. When the wafer W is normally transferred, the wafer W is transferred from the first linear transporter 6 or the second linear transporter 7 to the swing transporter 12 and transferred to the cleaning module 4.

[0054] FIG. 8 is a time chart showing an example of the detection signals of the sensors in an abnormal state. In FIG. 8, detection signals Sg1 to Sg3 from the sensors 811 to 813 are shown as in FIG. 7. In the example shown in FIG. 8, after time t0 when the desorption operation of the wafer W is started, the detection signal Sg3 turns "ON" first (timing t3), and the detection signals Sg1 and Sg2 turn "ON" a little later (timings t1 and t2). This means that the wafer W is desorbed from the top ring 31 in an inclined state, and the portion (first portion) corresponding to the sensor 813 is first seated on the mounting surface 820, and then the portions (second portion) corresponding to the sensors 811 and 812 are seated on the mounting surface 820. If the time difference Δt between the timing t3 and the timing t1 is equal to or greater than the abnormality determination time tref (S20: No), the controller 5 determines that there is a possibility that an abnormality has occurred in the wafer W due to the transfer of the wafer W (step S26), and ends the process.

[0055] 9 is a diagram showing an example of the time difference in the seating timing for each wafer. In FIG. 9, the horizontal axis indicates the number of wafers W handled after a new membrane 204 is used. The vertical axis indicates the time difference Δt in the seating timing when each wafer is transferred from the top ring 31 to the transfer device 800. The time difference Δt in the seating timing is the time difference Δt between the earliest and latest detection times of the wafer W by the multiple sensors 811-813. In the example shown in FIG. 9, the time difference Δt in the seating timing for the Na-th wafer W is abnormal at the abnormality determination time tref (see the dashed line), and it is determined that there is a possibility that an abnormality has occurred in the wafer W.

[0056] Research by the present inventors has revealed that even when the wafer W is detected by the multiple sensors 811-813 and the transfer operation of the wafer W from the top ring 31 to the mounting surface 820 is completed, the wafer W may be damaged or broken if the wafer W is tilted when released and seated on the mounting surface 820. For this reason, the controller 5 of this embodiment judges whether the operation of releasing the wafer W from the top ring 31 has been performed normally based on the time difference Δt between the seating timings of the wafer W detected by the multiple sensors 811-813. Then, when the time difference Δt is equal to or greater than the abnormality judgment time tref, it is judged that the wafer W is tilted when released and that there is a possibility that an abnormality such as damage or breakage has occurred in the wafer W. This makes it possible to judge an abnormality in the transfer of the wafer W, for example, before the wafer W is transferred to the swing transporter 12, thereby improving the processing efficiency in the substrate processing apparatus.

[0057] The present invention can also be described in the following forms. According to the first aspect, a substrate processing apparatus for performing a polishing process on a surface to be polished of a substrate includes a polishing table for supporting a polishing pad, a substrate holding surface formed of an elastic film, and The present invention proposes a substrate processing apparatus including a substrate holding device having a pressure chamber and configured to hold the substrate on the substrate holding surface and press the substrate against the polishing pad by the pressure in the pressure chamber, a transfer stage having a placement surface for placing the substrate and configured to transfer the substrate from the substrate holding device to the placement surface by a substrate release operation by the substrate holding device, a plurality of sensors including a first sensor and a second sensor configured to detect different portions of the substrate, for detecting that the substrate has been placed on the placement surface, and an abnormality determination unit for determining abnormality in the transfer of the substrate from the substrate holding device to the transfer stage based on a time difference between a first timing at which the first sensor detects that the substrate has been placed on the placement surface and a second timing at which the second sensor detects that the substrate has been placed on the placement surface. According to the first embodiment, when the substrate is transferred from the substrate holding device to the placement surface of the transfer stage, an abnormality in the transfer of the substrate can be detected based on detection by the plurality of sensors for detecting that the substrate has been placed on the placement surface.

[0058] [Mode 2] According to Mode 2, in Mode 1, the plurality of sensors includes at least three sensors including the first sensor and the second sensor, and the abnormality determination unit determines an abnormality in the transfer of the substrate from the substrate holding device to the transfer stage by determining the sensor among the plurality of sensors that detects the substrate being placed on the placement surface earliest as the first sensor and the sensor among the plurality of sensors that detects the substrate being placed on the placement surface latest as the second sensor. According to Mode 2, the abnormality in the transfer of the substrate can be determined based on detection by at least three sensors.

[0059] [Mode 3] According to Mode 3, in Mode 1 or 2, the abnormality determination unit determines that there is a possibility that an abnormality has occurred in the substrate due to the transfer of the substrate when all of the plurality of sensors detect that the substrate has been placed on the placement surface and the time difference is equal to or greater than a predetermined abnormality determination time. According to Mode 3, it is possible to determine that there is a possibility that an abnormality has occurred in the substrate due to the substrate being released in an inclined state.

[0060] [Mode 4] According to Mode 4, in Modes 1 to 3, when some of the plurality of sensors detect that the substrate is placed on the placement surface and the remaining sensors do not detect that the substrate is placed on the placement surface, the abnormality determination unit determines that the substrate is placed on the placement surface in an inclined state. According to Mode 4, it is possible to determine that the substrate is placed on the placement surface in an inclined state.

[0061] [Form 5] According to Form 5, in Forms 1 to 4, the multiple sensors have a light-projecting section that projects light so that it is blocked by the substrate when the substrate is placed on the mounting surface, and a light-receiving section that receives the light from the light-projecting section, and when all of the multiple sensors detect that the substrate has been placed on the mounting surface, the light projection from the light-projecting sections of the multiple sensors is stopped.

[0062] [Mode 6] According to Mode 6, in Modes 1 to 5, a release nozzle configured to inject pressurized fluid into a gap between the substrate holding surface and the substrate during a substrate detachment operation is provided. According to Mode 6, the substrate detachment operation can be performed by using the injection of pressurized fluid from the release nozzle.

[0063] [Mode 7] According to Mode 7, there is provided an abnormality determination method for determining abnormality in substrate transfer in a substrate processing apparatus, the substrate processing apparatus having a polishing table for supporting a polishing pad, a substrate holding surface formed of an elastic membrane, and a pressure chamber, the substrate holding surface being configured to hold the substrate and to press the substrate against the polishing pad by pressure in the pressure chamber. A method for determining an abnormality is proposed, comprising: a holding device; and a transport stage having a placement surface on which the substrate is placed and configured to transfer the substrate from the substrate holding device to the placement surface by a substrate release operation of the substrate holding device, the method including, when it is determined that the substrate is placed on the placement surface, determining an abnormality in the transfer of the substrate from the substrate holding device to the transport stage based on a time difference between a first timing at which it is detected that a first portion of the substrate has been placed on the placement surface and a second timing at which it is detected that a second portion of the substrate different from the first portion has been placed on the placement surface. According to the seventh aspect, when the substrate is transferred from the substrate holding device to the placement surface of the transport stage, an abnormality in the transfer of the substrate can be detected based on a time difference between the timing at which it is detected that a different portion of the substrate has been placed on the placement surface.

[0064] Although the embodiment of the present invention has been described above, the above-mentioned embodiment of the invention is intended to facilitate understanding of the present invention and does not limit the present invention. The present invention may be modified or improved without departing from the spirit thereof, and the present invention naturally includes equivalents thereof. Furthermore, within the scope of being able to solve at least a part of the above-mentioned problems or to achieve at least a part of the effects, any combination of the embodiments and modifications is possible, and any combination or omission of each component described in the claims and specification is possible. [Explanation of symbols]

[0065] W…wafer 2. Loading port 3 (3A~3D)…Polishing module 4. Cleaning module 5. Controller 6…First Linear Transporter 7…2nd Linear Transporter 10...Polishing pad 10a…Polished surface 22...Transport robot 30…Polishing table 31...Top ring (substrate holding device) 32...Polishing liquid supply nozzle 33…Dresser 34...Atomizer 202…Top ring body 203…Retainer ring 204...Elastic membrane 204...Membrane (elastic membrane) 205…Center room 206…Ripple Room 207…Outer room 208…Edge Room 209…Retainer ring pressurization chamber 800...Substrate transfer device 801...push-up pin 802...Release nozzle 811~813…Sensor 815…Light projector 816...Light receiving section 820…Placement surface

Claims

1. A substrate processing apparatus for performing a polishing process on a surface to be polished of a substrate, comprising: a polishing table for supporting the polishing pad; a substrate holding device having a substrate holding surface formed of an elastic film and a pressure chamber, the substrate being held on the substrate holding surface and configured to press the substrate against the polishing pad by pressure in the pressure chamber; a transfer stage having a placement surface on which the substrate is placed, the transfer stage being configured so that the substrate is transferred from the substrate holding device to the placement surface by a substrate release operation performed by the substrate holding device; a plurality of sensors, including a first sensor and a second sensor configured to detect different portions of the substrate, for detecting that the substrate has been placed on the placement surface; an abnormality determination unit that determines an abnormality in the transfer of the substrate from the substrate holding device to the transport stage based on a time difference between a first timing at which the first sensor detects that the substrate has been placed on the placement surface and a second timing at which the second sensor detects that the substrate has been placed on the placement surface; A substrate processing apparatus comprising:

2. the plurality of sensors includes at least three sensors including the first sensor and the second sensor; the abnormality determination unit determines an abnormality in the transfer of the substrate from the substrate holding device to the transport stage by determining, as a first sensor, a sensor among the plurality of sensors which detects that the substrate is placed on the placement surface earliest, and as a second sensor, a sensor among the plurality of sensors which detects that the substrate is placed on the placement surface latest. The substrate processing apparatus according to claim 1 .

3. 2. The substrate processing apparatus of claim 1, wherein the abnormality determination unit determines that an abnormality may have occurred in the substrate due to the transfer of the substrate when all of the plurality of sensors detect that the substrate has been placed on the placement surface and the time difference is equal to or greater than a predetermined abnormality determination time.

4. 4. The substrate processing apparatus of claim 3, wherein the abnormality determination unit determines that the substrate is placed on the placement surface at an angle when some of the plurality of sensors detect that the substrate has been placed on the placement surface and the remaining sensors do not detect that the substrate has been placed on the placement surface.

5. 4. The substrate processing apparatus of claim 3, wherein the plurality of sensors have a light-projecting section that projects light so that the light is blocked by the substrate when the substrate is placed on the placement surface, and a light-receiving section that receives the light from the light-projecting section, and when all of the plurality of sensors detect that the substrate has been placed on the placement surface, light projection from the light-projecting sections of the plurality of sensors is stopped.

6. The substrate processing apparatus according to claim 1 , further comprising a release nozzle configured to inject a pressurized fluid into a gap between the substrate holding surface and the substrate during a substrate release operation.

7. 1. A method for determining an abnormality in substrate transfer in a substrate processing apparatus, comprising: The substrate processing apparatus includes: a polishing table for supporting the polishing pad; The substrate holding surface is made of an elastic film, and the pressure chamber is configured to hold the substrate on the substrate holding surface and to press the substrate against the polishing pad by the pressure in the pressure chamber. A substrate holding device; a transfer stage having a placement surface on which the substrate is placed, the transfer stage being configured so that the substrate is transferred from the substrate holding device to the placement surface by a substrate release operation performed by the substrate holding device; Equipped with The abnormality determination method includes determining, when it is determined that the substrate has been placed on the placement surface, an abnormality in the transfer of the substrate from the substrate holding device to the transport stage based on a time difference between a first timing at which it is detected that a first portion of the substrate has been placed on the placement surface and a second timing at which it is detected that a second portion of the substrate, different from the first portion, has been placed on the placement surface.

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