JP5891127B2 - Polishing apparatus and polishing method - Google Patents

Description

  The present invention relates to a polishing apparatus and a polishing method, and more particularly to a polishing apparatus and a polishing method for polishing a substrate such as a wafer.

  In recent years, with higher integration and higher density of semiconductor devices, circuit wiring has become increasingly finer and the number of layers of multilayer wiring has increased. When trying to realize multilayer wiring while miniaturizing the circuit, the step becomes larger while following the surface unevenness of the lower layer, so as the number of wiring layers increases, the film coverage to the step shape in thin film formation (Step coverage) deteriorates. Therefore, in order to carry out multilayer wiring, it is necessary to improve the step coverage and perform a flattening process in an appropriate process. Further, since the depth of focus becomes shallower as the optical lithography becomes finer, it is necessary to planarize the surface of the semiconductor device so that the uneven steps on the surface of the semiconductor device are kept below the depth of focus.

Accordingly, in the semiconductor device manufacturing process, a planarization technique for the surface of the semiconductor device is becoming increasingly important. Among the planarization techniques, the most important technique is chemical mechanical polishing. This chemical mechanical polishing (hereinafter referred to as CMP) is performed by supplying a polishing liquid containing abrasive grains such as silica (SiO ₂ ) onto a polishing pad while sliding a substrate such as a wafer on a polishing surface. It is.

  A polishing apparatus for performing CMP includes a polishing table that supports a polishing pad having a polishing surface, and a substrate holding apparatus called a top ring or a polishing head for holding a wafer. When polishing a wafer using such a polishing apparatus, the wafer is pressed against the polishing surface with a predetermined pressure while the wafer is held by the top ring. Further, by relatively moving the polishing table and the top ring, the wafer comes into sliding contact with the polishing surface, and the surface of the wafer is polished to a flat and mirror surface.

  In such a polishing apparatus, when the relative pressing force between the wafer being polished and the polishing surface of the polishing pad is not uniform over the entire surface of the wafer, it depends on the pressing force applied to each part of the wafer. As a result, insufficient polishing or excessive polishing occurs. In order to equalize the pressing force on the wafer, a pressure chamber formed of an elastic membrane (membrane) is provided at the lower part of the top ring, and fluid such as air is supplied to the pressure chamber by the fluid pressure through the membrane. Polishing is performed by pressing a wafer against a polishing surface of a polishing pad.

  Since the polishing pad has elasticity, the pressing force applied to the outer peripheral edge of the wafer being polished becomes non-uniform, and only the outer peripheral edge of the wafer is often polished, so-called “edge fringing” may occur. is there. In order to prevent such edge drooping, the retainer ring that holds the outer peripheral edge of the wafer can be moved up and down with respect to the top ring main body (or carrier head main body) to polish the polishing pad located on the outer peripheral edge side of the wafer. The surface is pressed.

  A substrate delivery device called a pusher is installed in the vicinity of the top ring. This pusher has a function of lifting a wafer transferred by a transfer device such as a transfer robot and delivering the wafer to a top ring that has moved above the pusher. The pusher further has a function of transferring the wafer received from the top ring to a transfer device such as a transfer robot. The pusher includes a substrate detection sensor that detects the presence or absence of a wafer. When the substrate detection sensor detects the wafer, the pusher performs the following operation.

  In the polishing apparatus having the above-described configuration, after the polishing process on the polishing surface of the polishing pad is completed, the polished wafer is vacuum-adsorbed to the top ring, the top ring is raised, and then the wafer is moved to the pusher. Remove from the top ring. The separation of the wafer is performed by supplying a fluid to the pressure chamber to expand the membrane and peeling the wafer from the membrane. However, since the wafer is peeled off by the change in the shape of the membrane, the central portion of the wafer where the change in the shape of the membrane is small may not be peeled off from the membrane. Therefore, in order to easily remove the wafer from the top ring, as disclosed in Patent Documents 1 to 4, a release nozzle (substrate peeling promotion mechanism) is provided in the vicinity of the pusher. The release nozzle is a mechanism that assists the removal of the wafer by spraying a fluid (release shower) onto the contact portion between the wafer and the membrane. Hereinafter, the removal of the wafer in the prior art will be described with reference to FIGS.

  FIG. 11 is a schematic diagram showing a state at the time of wafer release in which the wafer is detached from the membrane. As shown in FIG. 11, a membrane 104 is attached to the lower surface of the top ring 100. When the wafer W is transferred, the wafer W is held on the substrate holding surface 104a constituted by the membrane 104 by vacuum suction. In FIG. 11, the membrane 104 is swollen to peel off the wafer W.

A release nozzle 153 for injecting the fluid 160 is provided in the vicinity of the top ring 100. Specifically, the release nozzle 153 is arranged so that the fluid 160 is sprayed to the contact portion between the wafer W and the membrane 104. As the fluid 160, for example, a mixed fluid composed of pure water and N ₂ (nitrogen) is used. By spraying the fluid 160 onto the contact portion between the wafer W and the membrane 104, the wafer W is easily detached from the top ring 100.

  A substrate detection sensor 170 that detects the presence or absence of the wafer W is attached to the upper surface of the pusher 150. When the wafer W is detached from the top ring 100 and the substrate detection sensor 170 detects the wafer W, the pusher 150 is lowered to pass the wafer W to a transfer device such as a transfer robot.

  FIG. 12 is a schematic diagram showing a state in which the membrane 104 is extended. In recent years, as the diameter of a wafer increases, its own weight increases. On the other hand, in order to reduce the load on the wafer, a soft material tends to be used for the membrane. Therefore, when the membrane 104 is pressurized and inflated, and the wafer W is peeled from the membrane 104, if the central portion of the wafer W remains attached to the membrane 104, the membrane 104 is formed by the weight of the wafer W and the inflated membrane 104. It will grow.

  When the membrane 104 is greatly extended, the position of the contact portion between the wafer W and the membrane 104 is lowered by a distance T1 from the position before the membrane 104 is extended (position indicated by a two-dot chain line in FIG. 12). Since the fluid 160 is ejected to a position before the membrane 104 is extended, the fluid 160 does not hit the contact portion (the position lowered by the distance T1) between the wafer W and the membrane 104. Therefore, the wafer W cannot be peeled off promptly.

  Further, when the membrane 104 is greatly extended, the substrate detection sensor 170 attached to the pusher 150 may detect the wafer W still attached to the membrane 104, that is, erroneously detect that the wafer W has been detached. As a result of such erroneous detection, the pusher 150 performs the following operation even though the wafer W is not detached from the membrane 104, and the wafer W is damaged. Therefore, further improvement is required for the process of removing the wafer W from the membrane 104.

  CMP is a process in which scrap wafers are easily generated. In some cases, more than half of the scrap wafer generated in the semiconductor device manufacturing process is generated by CMP. In particular, when the wafer is vacuum-adsorbed to the top ring for a long time and then the membrane is pressurized and inflated, and the wafer is peeled off from the membrane, local stress is applied to the wafer, and the fine wiring formed on the wafer breaks. Or the wafer may be damaged. Therefore, improving the wafer release process leads to improved productivity.

JP 2005-123485 A US Patent No. 7,044,832 JP 2010-46756 A JP 2011-258639 A JP 2006-303249 A

  The present invention has been made in view of the above-described conventional problems, and can polish the substrate quickly and reliably from the substrate holding device such as the top ring after the polishing of the substrate such as the wafer. An object is to provide an apparatus and a polishing method.

In order to achieve the above-described object, one embodiment of the present invention includes a polishing table for supporting a polishing pad, a substrate holding surface and a pressure chamber formed of an elastic film, and the substrate is held by the substrate holding surface. A substrate holding device that holds and presses the substrate against the polishing pad by the pressure in the pressure chamber, a vertical movement mechanism that moves the substrate holding device up and down, and a fluid jet to a contact portion between the substrate and the elastic film And a control unit for controlling the vertical movement mechanism and the substrate peeling promotion mechanism, wherein the control unit reduces the pressure drop in the pressure chamber. calculating a descent amount of the contact portion from said vertical movement mechanism is operated, the following lowering amount of the contact portion to lift the substrate holding device, thereafter, the contact portion by operating the substrate separation promoting mechanism A polishing apparatus characterized by injecting the fluid.

Another aspect of the present invention includes a polishing table for supporting a polishing pad, a substrate holding surface made of an elastic film, and a pressure chamber. The substrate is held by the substrate holding surface and the pressure in the pressure chamber is increased. A substrate holding device that presses the substrate against the polishing pad, a substrate peeling promoting mechanism that ejects a fluid to a contact portion between the substrate and the elastic film to release the substrate from the substrate holding surface, and the substrate peeling. An elevating mechanism that vertically moves the accelerating mechanism; and a control unit that controls the elevating mechanism and the substrate peeling accelerating mechanism, and the control unit calculates a descent amount of the contact portion from a pressure decrease amount in the pressure chamber. and, by operating the elevating mechanism, the following lowering amount of the contact portion to lift the substrate separation promoting mechanism, then to inject the fluid to the contact portion by operating the substrate separation promoting mechanism It is a polishing apparatus for the butterflies.

Another aspect of the present invention includes a polishing table for supporting a polishing pad, a substrate holding surface made of an elastic film, and a pressure chamber. The substrate is held by the substrate holding surface and the pressure in the pressure chamber is increased. A substrate holding device that presses the substrate against the polishing pad, a substrate peeling promoting mechanism that ejects a fluid to a contact portion between the substrate and the elastic film to release the substrate from the substrate holding surface, and the substrate peeling. A tilting mechanism for tilting the promoting mechanism; and a control unit for controlling the tilting mechanism and the substrate peeling promoting mechanism, wherein the control unit calculates a descending amount of the contact portion from a decreasing amount of the pressure in the pressure chamber. , said tilting mechanism is operated, by tilting the substrate separation accelerator mechanism according lowering amount of the contact portion, then, especially to injecting the fluid to the contact portion by operating the substrate separation promoting mechanism It is a polishing apparatus for the.

In a preferred aspect of the present invention, the control unit detects separation of the substrate from the substrate holding surface by detecting a minimum point of pressure in the pressure chamber .

Another aspect of the present invention is a method of polishing a substrate using a substrate holding device having a substrate holding surface and a pressure chamber made of an elastic film, and the substrate is pressed against a polishing pad by the pressure in the pressure chamber. Then, the substrate is polished while the substrate and the polishing pad are moved relative to each other, the polished substrate is held on the substrate holding surface, and the substrate and the elasticity are determined from the amount of pressure drop in the pressure chamber. calculating a descent amount of the contact portion with the film, when passing the substrate to a substrate transfer apparatus, prior Kise' touch by lifting the substrate holding apparatus according to the amount of descent of the parts, by injecting a fluid into the contact portion The substrate is separated from the substrate holding surface.

Another aspect of the present invention is a method of polishing a substrate using a substrate holding device having a substrate holding surface and a pressure chamber made of an elastic film, and the substrate is pressed against a polishing pad by the pressure in the pressure chamber. Then, the substrate is polished while the substrate and the polishing pad are moved relative to each other, the polished substrate is held on the substrate holding surface, and the substrate and the elasticity are determined from the amount of pressure drop in the pressure chamber. calculating a descent amount of the contact portion with the film, when passing the substrate to a substrate transfer apparatus according to the amount of descent of the front Kise' touching part, to lift the substrate separation promoting mechanism for ejecting a fluid, the substrate peeling accelerator mechanism The substrate is detached from the substrate holding surface by ejecting the fluid from the substrate to the contact portion.

Another aspect of the present invention is a method of polishing a substrate using a substrate holding device having a substrate holding surface and a pressure chamber made of an elastic film, and the substrate is pressed against a polishing pad by the pressure in the pressure chamber. Then, the substrate is polished while the substrate and the polishing pad are moved relative to each other, the polished substrate is held on the substrate holding surface, and the substrate and the elasticity are determined from the amount of pressure drop in the pressure chamber. calculating a descent amount of the contact portion with the film, when passing the substrate to a substrate transfer apparatus according to the amount of descent of the front Kise' touching portion, it is inclined substrate separation promoting mechanism for ejecting a fluid, the substrate peeling accelerator mechanism The substrate is detached from the substrate holding surface by ejecting the fluid from the substrate to the contact portion.

In a preferred aspect of the present invention, the separation of the substrate from the substrate holding surface is detected by detecting a minimum point of the pressure in the pressure chamber .

According to one aspect of the present invention, the fluid from the substrate peeling promotion mechanism can be jetted onto the contact portion between the substrate and the elastic film by raising and lowering the substrate holding device according to the descending amount of the contact portion between the substrate and the elastic film. it can.
Furthermore, according to another aspect of the present invention, the fluid from the substrate peeling promotion mechanism is brought into contact with the elastic film by raising or lowering or tilting the substrate peeling promotion mechanism according to the descending amount of the contact portion between the substrate and the elastic film. Can be sprayed on the part.

1 is a schematic diagram showing an overall configuration of a polishing apparatus according to a first embodiment of the present invention. It is typical sectional drawing of the top ring which hold | maintains a wafer and presses against the polishing pad on a polishing table. FIG. 3A is a diagram showing the reference position of the release nozzle, and FIG. 3B is a diagram showing how the top ring is raised. It is a figure which shows the other structure of a board | substrate detection sensor. It is a schematic diagram which shows the state which the membrane extended. It is a graph which shows the pressure in the center chamber which changes with time passage. It is a grinding | polishing apparatus which shows the 3rd Embodiment of this invention. It is a figure which shows the other structure of FIG. It is a grinding | polishing apparatus which shows the 4th Embodiment of this invention. It is a grinding | polishing apparatus which shows the 5th Embodiment of this invention. In the conventional polisher, it is a mimetic diagram showing the state at the time of wafer release which detaches a wafer from a membrane. It is a schematic diagram which shows the state which the membrane extended in the conventional grinding | polishing apparatus.

Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS. 1 to 10. 1 to 10, the same or corresponding components are denoted by the same reference numerals, and redundant description is omitted.
FIG. 1 is a schematic diagram showing the overall configuration of a polishing apparatus according to the first embodiment of the present invention. As shown in FIG. 1, the polishing apparatus includes a polishing table 10 and a top ring (substrate holding apparatus) 1 that holds a substrate such as a wafer to be polished and presses the polishing pad 20 on the polishing table 10. I have.

  The polishing table 10 is connected to a motor (not shown) disposed below the table 10a via a table shaft 10a, and is rotatable around the table shaft 10a. A polishing pad 20 is affixed to the upper surface of the polishing table 10, and the surface 20 a of the polishing pad 20 constitutes a polishing surface for polishing the wafer W. A polishing liquid supply nozzle 62 is installed above the polishing table 10, and the polishing liquid Q is supplied onto the polishing pad 20 on the polishing table 10 by the polishing liquid supply nozzle 62.

  The top ring 1 basically includes a top ring body 2 that presses the wafer W against the polishing surface 20a, and a retainer ring 3 that holds the wafer W and prevents the wafer W from jumping out of the top ring 1. Has been.

  The top ring 1 is connected to a top ring shaft 65, and the top ring shaft 65 moves up and down with respect to the top ring head 64 by a vertical movement mechanism 81. By the vertical movement of the top ring shaft 65, the entire top ring 1 is moved up and down relative to the top ring head 64 for positioning. A rotary joint 82 is attached to the upper end of the top ring shaft 65.

  A vertical movement mechanism 81 that moves the top ring shaft 65 and the top ring 1 up and down includes a bridge 84 that rotatably supports the top ring shaft 65 via a bearing 83, a ball screw 88 attached to the bridge 84, and a column 86. And a servo motor 90 provided on the support base 85. A support base 85 that supports the servo motor 90 is fixed to the top ring head 64 via a support 86.

  The ball screw 88 includes a screw shaft 88a connected to the servo motor 90 and a nut 88b into which the screw shaft 88a is screwed. The top ring shaft 65 moves up and down integrally with the bridge 84. Therefore, when the servo motor 90 is driven, the bridge 84 moves up and down via the ball screw 88, and thereby the top ring shaft 65 and the top ring 1 move up and down.

  The top ring shaft 65 is connected to the rotary cylinder 66 through a key (not shown). The rotary cylinder 66 includes a timing pulley 67 on the outer peripheral portion thereof. A top ring rotation motor 68 is fixed to the top ring head 64, and the timing pulley 67 is connected to a timing pulley 70 provided on the top ring rotation motor 68 via a timing belt 69. Accordingly, when the top ring rotary motor 68 is rotationally driven, the rotary cylinder 66 and the top ring shaft 65 rotate together via the timing pulley 70, the timing belt 69, and the timing pulley 67, and the top ring 1 rotates. The top ring head 64 is supported by a top ring head shaft 80 that is rotatably supported by a frame (not shown). The polishing apparatus includes a control unit 50 that controls each device in the apparatus including the top ring rotation motor 68 and the servo motor 90.

  The top ring 1 can hold the wafer W on the lower surface thereof. The top ring head 64 is configured to be pivotable about the top ring head shaft 80, and the top ring 1 holding the wafer W on the lower surface thereof is rotated from the receiving position of the wafer W by the rotation of the top ring head 64. Moved upwards. Polishing of the wafer W is performed as follows. The top ring 1 and the polishing table 10 are rotated, and the polishing liquid Q is supplied onto the polishing pad 20 from the polishing liquid supply nozzle 62 provided above the polishing table 10. In this state, the top ring 1 is lowered to press the wafer W against the polishing surface 20 a of the polishing pad 20. The wafer W is brought into sliding contact with the polishing surface 20a of the polishing pad 20, whereby the surface of the wafer W is polished.

  Next, the top ring in the polishing apparatus of the present invention will be described. FIG. 2 is a schematic cross-sectional view of the top ring 1 that holds the wafer W, which is an object to be polished, and presses it against the polishing pad 20 on the polishing table 10. In FIG. 2, only main components constituting the top ring 1 are illustrated.

  As shown in FIG. 2, the top ring 1 includes a membrane (elastic film) 4 that presses the wafer W against the polishing pad 20, a top ring body (also referred to as a carrier) 2 that holds the membrane 4, and a polishing pad 20. It is basically composed of a retainer ring 3 that directly presses. The top ring body 2 is made of a substantially disk-shaped member, and the retainer ring 3 is attached to the outer peripheral portion of the top ring body 2. The top ring body 2 is formed of a resin such as engineering plastic (for example, PEEK). On the lower surface of the top ring body 2, a membrane 4 that is in contact with the back surface of the wafer W is attached. The membrane 4 is formed of a rubber material having excellent strength and durability, such as ethylene propylene rubber (EPDM), polyurethane rubber, silicon rubber and the like.

  The membrane 4 has a plurality of concentric partition walls 4a, and by these partition walls 4a, a plurality of pressure chambers, that is, a circular center chamber 5 and an annular shape are provided between the upper surface of the membrane 4 and the lower surface of the top ring body 2. A ripple chamber 6, an annular outer chamber 7, and an annular edge chamber 8 are formed. A center chamber 5 is formed at the center of the top ring main body 2, and a ripple chamber 6, an outer chamber 7, and an edge chamber 8 are sequentially formed concentrically from the center toward the outer peripheral direction.

  The wafer W is held on the substrate holding surface 4b formed of the membrane 4. The membrane 4 has a plurality of wafer suction holes 4 h at positions corresponding to the ripple chamber 6. In this embodiment, the hole 4 h is provided at the position of the ripple chamber 6, but it may be provided at a position other than the ripple chamber 6. In the top ring body 2, a flow path 11 communicating with the center chamber 5, a flow path 12 communicating with the ripple chamber 6, a flow path 13 communicating with the outer chamber 7, and a flow path 14 communicating with the edge chamber 8 are formed. Has been. The flow paths 11, 13, and 14 are connected to the flow paths 21, 23, and 24 via the rotary joint 82, respectively. The flow paths 21, 23, 24 are connected to the pressure adjusting unit 30 via valves V1-1, V3-1, V4-1 and pressure regulators R1, R3, R4, respectively. The flow paths 21, 23, and 24 are connected to the vacuum source 31 via valves V1-2, V3-2, and V4-2, respectively, and via valves V1-3, V3-3, and V4-3. Can communicate with the atmosphere.

  The flow path 12 communicating with the ripple chamber 6 is connected to the flow path 22 via the rotary joint 82. And the flow path 22 is connected to the pressure adjustment part 30 via the steam-water separation tank 35, valve | bulb V2-1, and pressure regulator R2. The flow path 22 is connected to the vacuum source 87 via the steam-water separation tank 35 and the valve V2-2, and can communicate with the atmosphere via the valve V2-3.

  An annular retainer ring pressurizing chamber 9 formed of an elastic film is disposed immediately above the retainer ring 3, and the retainer ring pressurizing chamber 9 includes a flow path 15 and a rotary joint formed in the top ring body 2. It is connected to the flow path 26 via 82. The flow path 26 is connected to the pressure adjusting unit 30 via the valve V5-1 and the pressure regulator R5. The flow path 26 is connected to the vacuum source 31 via a valve V5-2 and can communicate with the atmosphere via a valve V5-3. The pressure regulators R1, R2, R3, R4, and R5 are fluids (air, nitrogen, etc.) supplied from the pressure adjusting unit 30 to the center chamber 5, the ripple chamber 6, the outer chamber 7, the edge chamber 8, and the retainer ring pressurizing chamber 9, respectively. Pressure adjustment function for adjusting the pressure of the gas. Pressure regulators R1, R2, R3, R4, R5 and valves V1-1 to V1-3, V2-1 to V2-3, V3-1 to V3-3, V4-1 to V4-3, V5-1 V5-3 is connected to the control part 50 (refer FIG. 1), and those operations are controlled. Further, pressure sensors P1, P2, P3, P4, P5 and flow sensors F1, F2, F3, F4, F5 are installed in the flow paths 21, 22, 23, 24, 26, respectively.

  The pressure in the center chamber 5, the ripple chamber 6, the outer chamber 7, the edge chamber 8, and the retainer ring pressurizing chamber 9 is measured by pressure sensors P1, P2, P3, P4, and P5, respectively. The flow rates of the pressurized fluid supplied to the outer chamber 7, the edge chamber 8, and the retainer ring pressurizing chamber 9 are measured by flow sensors F1, F2, F3, F4, and F5, respectively.

  In the top ring 1 configured as shown in FIG. 2, as described above, the center chamber 5 is formed at the center of the top ring main body 2, and the ripples are sequentially concentrically from the center toward the outer peripheral direction. The chamber 6, the outer chamber 7, and the edge chamber 8 are formed, and the pressure of the fluid supplied to the center chamber 5, the ripple chamber 6, the outer chamber 7, the edge chamber 8 and the retainer ring pressurizing chamber 9 is adjusted by the pressure adjusting unit 30 and the pressure. Each of the regulators R1, R2, R3, R4, and R5 can be adjusted independently. With such a structure, the pressing force for pressing the wafer W against the polishing pad 20 can be adjusted for each region of the wafer, and the pressing force for the retainer ring 3 to press the polishing pad 20 can be adjusted.

Next, a series of polishing processing steps by the polishing apparatus configured as shown in FIGS. 1 and 2 will be described.
The top ring 1 receives the wafer W at the substrate delivery position and holds it by vacuum suction. Vacuum suction of the wafer W is performed by forming a vacuum in the plurality of holes 4 h by the vacuum source 87. The top ring 1 holding the wafer W is lowered to a preset polishing setting position of the top ring 1. In this polishing setting position, the retainer ring 3 is in contact with the polishing surface 20a of the polishing pad 20. However, since the wafer W is held by the top ring 1 before polishing, the lower surface (surface to be polished) of the wafer W is held. And a polishing surface 20a of the polishing pad 20 has a slight gap (for example, about 1 mm). At this time, both the polishing table 10 and the top ring 1 are rotationally driven. In this state, the membrane 4 on the back surface side of the wafer W is expanded, the lower surface of the wafer W is brought into contact with the polishing surface 20a of the polishing pad 20, and the polishing pad 20 and the wafer W are moved relative to each other. The surface is polished.

  After completion of the wafer processing process on the polishing pad 20, the wafer W is attracted to the top ring 1, the top ring 1 is raised, the top ring 1 is moved to a pusher (described later), and the wafer W is released (released). )I do.

  FIG. 3A is a diagram showing a reference position of the release nozzle 93, and FIG. 3B is a diagram showing how the top ring 1 is raised. The pusher 92 is disposed adjacent to the polishing table 10. When the wafer W is transferred to the pusher 92, the wafer W is held on the substrate holding surface 4 b configured by the membrane 4 by vacuum suction, and the top ring 1 is held on the pusher 92 in a state where the wafer W is sucked on the top ring 1. Move upward.

In the vicinity of the top ring 1, a release nozzle (substrate peeling promotion mechanism) 93 for ejecting the fluid 95 is provided. As shown in FIG. 3A, the vertical position of the contact portion between the wafer 4 and the membrane 4 before the membrane 4 is greatly extended is set as the reference position of the release nozzle 93, and the release nozzle 93 is located at this reference position. Installed. The release nozzle 93 ejects the fluid 95 to the contact portion between the wafer W and the membrane 4. As the fluid 95, for example, a mixed fluid composed of pure water and N ₂ (nitrogen) is used. By spraying the fluid 95 onto the contact portion between the wafer W and the membrane 4, the wafer W is easily detached from the top ring 1. A substrate detection sensor 96 that detects the presence or absence of the wafer W is attached to the upper surface of the pusher 92. When the wafer W is detached from the top ring 1 and the substrate detection sensor 96 detects the wafer W, the pusher 92 is lowered to pass the wafer W to a transfer device such as a transfer robot.

  Various types of sensors can be used as the substrate detection sensor. For example, the substrate detection sensor 96 shown in FIGS. 3A and 3B is a contact-type substrate detection sensor that detects the separation of the wafer W by contact with the wafer W. As shown in FIG. 4, a non-contact type substrate detection sensor including a light projecting unit 105 and a light receiving unit 106 may be installed instead of the substrate detection sensor 96. The substrate detection sensor detects the separation of the wafer W when the light irradiated from the light projecting unit 105 toward the light receiving unit 106 is blocked by the wafer W.

  As described with reference to FIG. 12, when the wafer W is detached, the membrane 4 is greatly expanded due to the weight of the wafer W and the swelled membrane 4, and the contact portion between the wafer W and the membrane 4 is lowered. A two-dot chain line shown in FIG. 3A indicates a state where the contact portion between the wafer W and the membrane 4 is lowered. When the fluid 95 is sprayed to a position before the membrane 4 extends, the fluid 95 does not hit the contact portion between the wafer W and the membrane 4. Therefore, in the present embodiment, as shown in FIG. 3B, the top ring 1 is raised from the reference position of the release nozzle 93 by a distance T2 according to the descending amount of the wafer W. Thereby, the fluid 95 can be accurately applied to the contact portion between the wafer W and the membrane 4. The release nozzle 93 may be installed below the reference position. In this case, the top ring 1 is lowered by the distance T2. The top ring 1 is moved up and down by a vertical movement mechanism 81. The calculation method of the distance T2 is as follows.

FIG. 5 is a schematic view showing a state in which the membrane 4 is extended. Assuming that the increased volume from the initial volume of the center chamber 5 when the membrane 4 is extended is a cylindrical space indicated by the symbol ΔV in FIG. 5, according to Boyle's law, when the temperature is constant, The following relational expression holds.
P ₀ × V ₀ = (P ₀ −P) × (V ₀ + S × h)
Therefore,
h = P × V ₀ / S (P ₀ −P)
Here, P ₀ : Atmospheric pressure [Pa], V ₀ : Initial volume [m ³ ] of the center chamber, S: Horizontal cross-sectional area [m ² ] of the center chamber, h: Elongation amount [m] of the membrane, P: The pressure drop amount (positive value) [Pa] in the center chamber. The initial volume V ₀ of the center chamber 5 is obtained in advance by measurement or calculation.

  In the above relational expression, the product of the horizontal sectional area S of the center chamber 5 and the amount of elongation of the membrane 4 (that is, the amount of downward movement of the contact portion between the wafer W and the membrane 4) h is the increased volume ΔV. The control unit 50 calculates the value of the elongation amount h from the above relational expression, and determines the distance T2 from the value of the elongation amount h. The distance T2 may be the same as or smaller than the elongation amount h. The control unit 50 functions as a calculation unit that calculates the elongation amount h. The elongation h is calculated from the numerical value of the pressure drop in the center chamber 5. The pressure in the center chamber 5 is measured by the pressure sensor P1. By raising the top ring 1 by the distance T2, the fluid 95 from the release nozzle 93 can be accurately applied to the contact portion between the wafer W and the membrane 4. Therefore, the wafer W can be quickly and reliably detached from the top ring 1.

  FIG. 6 is a graph showing the pressure in the center chamber 5 that changes over time. The vertical axis represents the pressure in the center chamber 5, and the horizontal axis represents time. As shown in this graph, when the wafer W begins to peel (that is, the membrane 4 begins to expand), the volume of the center chamber 5 expands and the pressure in the center chamber 5 decreases. When the wafer W is detached from the membrane 4, the pressure in the center chamber 5 returns to the state before the membrane 4 is extended. The minimum point of the pressure in the center chamber 5 is the separation point of the wafer W.

  The ejection of the fluid 95 is started before the membrane 4 starts to expand, and is ended after the wafer W is detached. The controller 50 monitors the change in the pressure in the center chamber 5 and detects the separation of the wafer W from the substrate holding surface 4b based on the change in pressure. Specifically, it is correctly determined whether or not the wafer W is detached from the membrane 4 by detecting the minimum point of pressure. When the minimum point is not detected within a predetermined time, the control unit 50 determines that the wafer W has not detached from the membrane 4. The controller 50 can prevent the wafer W from being damaged by lowering the pusher 92 on which the wafer W is placed after detecting the minimum pressure point in the center chamber 5.

  As a second embodiment of the present invention, it is also possible to determine whether or not the wafer W has detached from the membrane 4 from the cumulative value of the flow rate of the fluid flowing into the center chamber 5. The accumulated value of the flow rate of the fluid from the time when the wafer W separation operation is started corresponds to the increased volume ΔV of the center chamber 5. Therefore, by dividing the increased volume ΔV by the horizontal sectional area S of the center chamber 5, the extension amount h of the membrane 4 can be calculated. The controller 50 calculates the value of the elongation amount h from ΔV and S, and determines the distance T2 from the value of the elongation amount h. The distance T2 may be the same as or smaller than the elongation amount h.

  A specific method for calculating the elongation h is as follows. First, the valve V1-3 is closed so that the flow path 21 does not communicate with the atmosphere. Next, the pressure regulator R <b> 1 is adjusted so that a fluid at atmospheric pressure is supplied into the center chamber 5. In this case, the pressure regulator R1 functions as a relief valve that is opened at a pressure higher than atmospheric pressure. Since the fluid flowing into the center chamber 5 passes through the flow rate sensor F1, the control unit 50 calculates the increased volume ΔV of the center chamber 5 from the accumulated value of the flow rate of the fluid passing through the flow rate sensor F1, and further divides ΔV by S. The elongation amount h can be calculated. As shown in FIG. 3B, the fluid 95 from the release nozzle 93 can be accurately applied to the contact portion between the wafer W and the membrane 4 by raising the top ring 1 by a distance T2. Therefore, the wafer W can be quickly and reliably detached from the top ring 1.

FIG. 7 is a polishing apparatus showing a third embodiment of the present invention. Other configurations that are not specifically described are the same as the configurations shown in the first embodiment, and thus redundant description thereof is omitted.
As shown in FIG. 7, a distance measuring sensor 40 is embedded in the lower surface of the top ring body 2. The distance measurement sensor 40 measures a distance D1 between the distance measurement sensor 40 and the back surface of the membrane 4. This distance D1 is the elongation amount h of the membrane 4. The control unit 50 determines the distance T2 (see FIG. 3B) from the value of the extension amount h. The distance T2 may be the same as or smaller than the elongation amount h. By raising the top ring 1 by the distance T2, the fluid 95 from the release nozzle 93 can be accurately applied to the contact portion between the wafer W and the membrane 4. Therefore, the wafer W can be quickly and reliably detached from the top ring 1.

  FIG. 8 is a diagram showing another configuration of FIG. In FIG. 8, the distance measuring sensor 40 is embedded in the upper surface of the pusher 92. The distance measurement sensor 40 measures a distance D2 between the distance measurement sensor 40 and the surface of the wafer W. The distance D3 between the distance measuring sensor 40 and the top ring body 2 is measured in advance. The distance D2 between the distance measurement sensor 40 and the surface of the wafer W is measured by the distance measurement sensor 40, and the control unit 50 subtracts the distance D2 and the thickness of the wafer W from the distance D3 to obtain the distance D4. The distance D4 is the extension amount h of the membrane 4. The controller 50 determines the distance T2 from the value of the elongation amount h. The distance T2 may be the same as or smaller than the elongation amount h. By raising the top ring 1 by the distance T2, the fluid 95 from the release nozzle 93 can be accurately applied to the contact portion between the wafer W and the membrane 4. Therefore, the wafer W can be quickly and reliably detached from the top ring 1.

FIG. 9 is a polishing apparatus showing a fourth embodiment of the present invention. Other configurations that are not specifically described are the same as the configurations shown in the first embodiment, and thus redundant description thereof is omitted.
As shown in FIG. 9, the release nozzle 93 is attached to an elevating mechanism 98 and can be moved up and down. In the fourth embodiment, instead of the top ring 1 being raised, the release nozzle 93 is lowered to the contact portion between the wafer W and the membrane 4. When the release nozzle 93 is lowered from the predetermined reference position (see FIG. 3A) by the distance T2, the fluid 95 can be sprayed to the contact portion between the wafer W and the membrane 4 without raising the top ring 1. it can. As a result, the wafer W can be quickly and reliably detached from the top ring 1. The release nozzle 93 may be installed below the reference position. In this case, the release nozzle 93 is raised by a distance T2.

FIG. 10 is a polishing apparatus showing a fifth embodiment of the present invention. Other configurations that are not specifically described are the same as the configurations shown in the first embodiment, and thus redundant description thereof is omitted.
As shown in FIG. 10, the release nozzle 93 is attached to the tilting mechanism 99, and the release nozzle 93 can be tilted with respect to the horizontal direction. In the fifth embodiment, the release nozzle 93 is tilted so that the ejection port 93 a of the release nozzle 93 is directed to the contact portion between the wafer W and the membrane 4. The inclination angle of the release nozzle 93 is determined based on the extension amount h of the membrane 4. By tilting the release nozzle 93 by an angle determined based on the extension amount h, the fluid 95 can be accurately applied to the contact portion between the wafer W and the membrane 4. Therefore, the wafer W can be quickly and reliably detached from the top ring 1.

  The first to fifth embodiments described above can be combined as appropriate. For example, raising / lowering of the top ring 1, raising / lowering of the release nozzle 93, and tilting of the release nozzle 93 may be combined.

  Although the embodiment of the present invention has been described so far, the present invention is not limited to the above-described embodiment, and it is needless to say that the present invention may be implemented in various different forms within the scope of the technical idea.

1,100 Substrate holder (top ring)
2 Top ring body 3 Retainer ring 4,104 Elastic membrane
4a Partition 4b, 104a Substrate holding surface 4h Hole 5 Center chamber 6 Ripple chamber 7 Outer chamber 8 Edge chamber 9 Retainer ring pressurizing chamber 10 Polishing table 10a Table shaft 11, 12, 13, 14, 15, 21, 22, 23, 24, 26 Flow path 20 Polishing pad 20a Polishing surface 30 Pressure adjusting unit 31, 87 Vacuum source 35 Air / water separation tank 40 Distance measuring sensor 50 Control unit 62 Polishing liquid supply nozzle 65 Top ring shaft 66 Rotating cylinder 67 Timing pulley 68 Top ring Rotating motor 69 Timing belt 70 Timing pulley 80 Top ring head shaft 81 Vertical movement mechanism 82 Rotary joint 83 Bearing 84 Bridge 85 Support base 86 Post 88 Ball screw 88a Screw shaft 88b Nut 90 Servo motor 92, 150 Substrate holder Handing device (Pusher)
93,153 Substrate peeling promotion mechanism (release nozzle)
93a Ejection port 95,160 Fluid 96,170 Substrate detection sensor 98 Elevating mechanism 99 Tilt mechanism 105 Light projecting unit 106 Light receiving unit F1-F5 Flow rate sensor R1-R5 Pressure regulator P1-P5 Pressure sensor V1-1-V1-3, V2 -1 to V2-3, V3-1 to V3-3, V4-1 to V4-3, V5-1 to V5-3

Claims (10)

A polishing table for supporting the polishing pad;
A substrate holding device having a substrate holding surface and a pressure chamber made of an elastic film, holding the substrate by the substrate holding surface, and pressing the substrate against the polishing pad by pressure in the pressure chamber;
A vertically moving mechanism for vertically moving the substrate holding device;
A substrate peeling promotion mechanism that ejects fluid to a contact portion between the substrate and the elastic film to release the substrate from the substrate holding surface;
A controller for controlling the vertical movement mechanism and the substrate peeling promotion mechanism,
The control unit calculates a descending amount of the contact portion from a decrease amount of pressure in the pressure chamber, operates the vertical movement mechanism to raise and lower the substrate holding device according to the descending amount of the contact portion, and then A polishing apparatus, wherein the substrate peeling promotion mechanism is operated to inject the fluid onto the contact portion.   The polishing apparatus according to claim 1, wherein the control unit detects the separation of the substrate from the substrate holding surface by detecting a minimum point of the pressure in the pressure chamber. A polishing table for supporting the polishing pad;
A substrate holding device having a substrate holding surface and a pressure chamber made of an elastic film, holding the substrate by the substrate holding surface, and pressing the substrate against the polishing pad by pressure in the pressure chamber;
A substrate peeling promotion mechanism that ejects fluid to a contact portion between the substrate and the elastic film to release the substrate from the substrate holding surface;
An elevating mechanism for moving the substrate peeling promotion mechanism up and down;
A controller for controlling the lifting mechanism and the substrate peeling promotion mechanism,
The control unit calculates a descending amount of the contact portion from an amount of decrease in pressure in the pressure chamber, operates the lifting mechanism to raise and lower the substrate peeling promotion mechanism according to the descending amount of the contact portion, and A polishing apparatus, wherein the substrate peeling promotion mechanism is operated to inject the fluid onto the contact portion. The polishing apparatus according to claim 3 , wherein the control unit detects the separation of the substrate from the substrate holding surface by detecting a minimum point of pressure in the pressure chamber. A polishing table for supporting the polishing pad;
A substrate holding device having a substrate holding surface and a pressure chamber made of an elastic film, holding the substrate by the substrate holding surface, and pressing the substrate against the polishing pad by pressure in the pressure chamber;
A substrate peeling promotion mechanism that ejects fluid to a contact portion between the substrate and the elastic film to release the substrate from the substrate holding surface;
A tilting mechanism for tilting the substrate peeling promotion mechanism;
A controller that controls the tilt mechanism and the substrate peeling promotion mechanism,
The control unit calculates a descending amount of the contact portion from an amount of decrease in pressure in the pressure chamber, operates the tilt mechanism, tilts the substrate peeling promotion mechanism according to the descending amount of the contact portion, and then A polishing apparatus, wherein the substrate peeling promotion mechanism is operated to inject the fluid onto the contact portion. The polishing apparatus according to claim 5 , wherein the control unit detects separation of the substrate from the substrate holding surface by detecting a minimum point of pressure in the pressure chamber. A method of polishing a substrate using a substrate holding device having a substrate holding surface and a pressure chamber made of an elastic film,
The substrate is pressed against the polishing pad by the pressure in the pressure chamber, and the substrate is polished while the substrate and the polishing pad are moved relative to each other.
Hold the substrate after polishing on the substrate holding surface,
Calculate the descending amount of the contact portion between the substrate and the elastic film from the decreasing amount of the pressure in the pressure chamber,
When transferring the substrate to the substrate transfer apparatus, by lifting the substrate holding apparatus according to the amount of descent of the front Kise' touching portion, that of separating the substrate from the substrate holding surface by ejecting a fluid to the contact portion A characteristic polishing method. A method of polishing a substrate using a substrate holding device having a substrate holding surface and a pressure chamber made of an elastic film,
The substrate is pressed against the polishing pad by the pressure in the pressure chamber, and the substrate is polished while the substrate and the polishing pad are moved relative to each other.
Hold the substrate after polishing on the substrate holding surface,
Calculate the descending amount of the contact portion between the substrate and the elastic film from the decreasing amount of the pressure in the pressure chamber,
When transferring the substrate to the substrate transfer apparatus, in accordance with the amount of descent of the front Kise' touching part, to lift the substrate separation promoting mechanism for ejecting a fluid, by injecting the fluid to the contact portion from the substrate peeling accelerator mechanism A polishing method, wherein the substrate is detached from the substrate holding surface. A method of polishing a substrate using a substrate holding device having a substrate holding surface and a pressure chamber made of an elastic film,
The substrate is pressed against the polishing pad by the pressure in the pressure chamber, and the substrate is polished while the substrate and the polishing pad are moved relative to each other.
Hold the substrate after polishing on the substrate holding surface,
Calculate the descending amount of the contact portion between the substrate and the elastic film from the decreasing amount of the pressure in the pressure chamber,
When transferring the substrate to the substrate transfer apparatus, in accordance with the amount of descent of the front Kise' touching portion, it is inclined substrate separation promoting mechanism for ejecting a fluid, by injecting the fluid to the contact portion from the substrate peeling accelerator mechanism A polishing method, wherein the substrate is detached from the substrate holding surface. The polishing method according to any one of claims 7 to 9, characterized in that detecting the detachment from the substrate holding surface of the substrate by detecting a minimum point of the pressure in the pressure chamber.

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