JP2018051762A - Polishing device and polishing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To inexpensively provide a polishing device that can implement multistep polishing of a substrate.SOLUTION: A polishing device includes: a plurality of polishing tables 30C and 30D for supporting each abrasive pad 10; a first polishing head 31C having a plurality of pressure chambers C1 to C4 in which pressure is generated for pressing a substrate W against the abrasive pad 10; and a second polishing head 31D having a plurality of pressure chambers D1 to D4 in which pressure is generated for pressing the substrate W against the abrasive pad 10. Arrangement of the plurality of pressure chambers D1 to D4 of the second polishing head 31D is different from an arrangement of the plurality of pressure chambers C1 to C4 of the first polishing head 31C.SELECTED DRAWING: Figure 9

Description

  The present invention relates to a polishing apparatus and a polishing method for polishing a substrate such as a wafer, and more particularly to a polishing apparatus and a polishing method for polishing a substrate using a plurality of types of polishing heads having different structures.

  The CMP apparatus is a polishing apparatus that chemically and mechanically polishes a wafer. A polishing apparatus called a CMP apparatus includes a plurality of polishing tables and a plurality of polishing heads in order to perform multistage polishing of a wafer. The wafer is sequentially transferred to the polishing pad on the polishing table, and is sequentially polished by each polishing head on the polishing pad. For example, rough polishing of the wafer is performed as the first stage polishing, and final polishing of the wafer is performed as the second stage polishing.

  The polishing apparatus is required to execute a polishing recipe according to various polishing processes. In order to meet such a demand, a high performance polishing head is used as the plurality of polishing heads described above. Specifically, the polishing head includes a membrane for independently pressing a plurality of regions of the wafer, a retainer ring for pressing the polishing pad around the wafer (see, for example, Patent Document 1).

  However, such a high-performance polishing head has a complicated structure and has expensive consumable parts (membrane, retainer ring, etc.). For this reason, maintenance cost and running cost increase. Further, when the maintenance frequency increases, the operating rate of the apparatus decreases.

  The above-described polishing head has a plurality of pressure chambers composed of a membrane. The pressure in these pressure chambers can be appropriately changed, and the polishing head can apply different polishing pressures to a plurality of regions of the wafer. Therefore, the polishing head can polish the wafer while controlling the polishing rate for each region of the wafer.

  However, this type of polishing head cannot control the polishing rate in a region smaller than the pressure chamber. If more pressure chambers are provided, finer control of the wafer profile is possible, but the number of pressure chambers that can be provided in the polishing head is limited. Further, the polishing head cannot positively control the wafer polishing rate at the boundary between the pressure chambers. For this reason, the polishing rate may be low at the boundary between the pressure chambers.

JP 2010-50436 A

Accordingly, a first object of the present invention is to provide a polishing apparatus capable of performing multi-stage polishing of a substrate such as a wafer at a low cost.
A second object of the present invention is to provide a polishing apparatus and a polishing method capable of more precisely controlling the profile of a substrate such as a wafer.

In order to achieve the above-described object, one embodiment of the present invention includes a plurality of polishing tables each supporting a polishing pad, and a plurality of pressure chambers that generate pressure for pressing a substrate against the polishing pad. 1 polishing head and a second polishing head having a plurality of pressure chambers for generating pressure for pressing the substrate against the polishing pad, and the arrangement of the plurality of pressure chambers of the second polishing head is as follows: The polishing apparatus is different from the arrangement of the plurality of pressure chambers of the first polishing head.
In a preferred aspect, the plurality of pressure chambers of the second polishing head are arranged at positions corresponding to positions of boundaries between the plurality of pressure chambers of the first polishing head.
In a preferred aspect, at least two of the plurality of pressure chambers of the second polishing head are arranged at positions corresponding to any one of the plurality of pressure chambers of the first polishing head. It is characterized by.

  In another aspect, the first polishing head having a plurality of pressure chambers presses the substrate against a polishing pad to polish the substrate, and then the plurality of pressure chambers of the first polishing head are different in arrangement from the plurality of pressure chambers. And polishing the substrate by pressing the substrate against a polishing pad with a second polishing head having a pressure chamber.

  One reference example of the present invention includes a plurality of polishing tables for supporting polishing pads, a plurality of polishing heads for pressing a substrate against the polishing pad, and the substrate as at least two of the plurality of polishing heads. And a plurality of polishing heads having different structures from each other.

In a preferred aspect of the above reference example, the plurality of polishing heads include at least one isobaric polishing head that applies a uniform pressure to the substrate, and at least one multi-chamber polishing head that can apply different pressures to the substrate. It is characterized by including.
In a preferred aspect of the above reference example, the at least one isobaric polishing head is at least one of a rigid polishing head and a single chamber polishing head, and the rigid polishing head includes a rigid body having a circular flat surface; A circular substrate holding member that is bonded to the flat surface and presses the substrate against the polishing pad; and a guide ring that holds the substrate in a non-contact manner with the polishing pad, and the single chamber polishing head includes a carrier, A plate disposed below the carrier, a circular elastic film forming a single pressure chamber under the plate, and a retainer ring fixed to the carrier so as to surround the substrate and pressing the polishing pad It is characterized by comprising.
In a preferred embodiment of the above reference example, the at least one multi-chamber polishing head is at least one of a first multi-chamber polishing head and a second multi-chamber polishing head, and the first multi-chamber polishing head includes: A carrier, a plate disposed below the carrier, a circular elastic film forming a plurality of pressure chambers under the plate, and a retainer fixed to the carrier so as to surround the substrate and pressing the polishing pad The second multi-chamber polishing head includes a carrier, a circular elastic film forming a plurality of pressure chambers under the carrier, and a retainer that is disposed so as to surround the substrate and presses the polishing pad And a ring, and an annular elastic membrane provided between the retainer ring and the carrier and having an annular pressure chamber formed therein.

According to one aspect of the present invention, a first polishing head and a second polishing head having pressure chambers with different arrangements are used. The two polishing heads can press different areas of the substrate against the polishing pad. That is, when two polishing heads having differently arranged pressure chambers are used, the same effect as that obtained when the number of pressure chambers in one polishing head is substantially increased can be obtained. Therefore, the profile of the substrate can be controlled more precisely.
According to one reference example of the present invention, a plurality of polishing heads having different structures, that is, polishing heads having different initial costs and maintenance costs are used. When a plurality of polishing heads having different structures are used, the frequency of use of the polishing head having a high maintenance cost can be reduced. Therefore, the maintenance cost for the entire polishing apparatus can be reduced.

It is a figure showing a polish device concerning one embodiment of the present invention. It is a perspective view which shows a 1st grinding | polishing unit typically. It is sectional drawing which shows the grinding | polishing head of a 1st grinding | polishing unit. It is sectional drawing which shows the grinding | polishing head of a 2nd grinding | polishing unit. It is sectional drawing which shows the grinding | polishing head of a 3rd grinding | polishing unit. It is sectional drawing which shows the grinding | polishing head of a 4th grinding | polishing unit. It is a figure which shows the example which performs rough polishing of a wafer, 1st profile control polishing of a wafer, 2nd profile control polishing of a wafer, and final polishing of a wafer in this order using four polishing heads. FIG. 8A is a schematic diagram showing a part of the pressure chamber of the first multi-chamber polishing head and a part of the corresponding wafer profile, and FIG. 8B is a diagram of the second multi-chamber polishing head. It is a schematic diagram which shows a part of pressure chamber and a part of the profile of a corresponding wafer. It is a schematic diagram which shows the example of arrangement | positioning of the pressure chamber of a 1st multiple chamber polishing head, and arrangement | positioning of the pressure chamber of a 2nd multiple chamber polishing head. It is a figure which shows arrangement | positioning of the pressure chamber which can perform the profile adjustment of the peripheral part (or edge part) of a wafer precisely. It is a figure which shows arrangement | positioning of the pressure chamber which can perform the profile adjustment of the intermediate part of a wafer precisely. It is a figure which shows arrangement | positioning of the pressure chamber which can perform the profile adjustment of the center part of a wafer precisely. It is a figure which shows the example which has arrange | positioned the rigid body polishing head in the 1st grinding | polishing unit and the 4th grinding | polishing unit, and has arrange | positioned the 2nd multiple chamber grinding | polishing head in the 2nd grinding | polishing unit and the 3rd grinding | polishing unit. It is a figure which shows the example of the combination of the grinding | polishing head selected according to grinding | polishing targets, such as the grinding | polishing amount of a wafer, the request | requirement of planarization of a wafer surface, and the request | requirement that there are no defects, such as a scratch.

  Hereinafter, a polishing apparatus according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing a polishing apparatus according to an embodiment of the present invention. As shown in FIG. 1, this polishing apparatus includes a substantially rectangular housing 1, and the interior of the housing 1 is divided into a load / unload section 2, a polishing section 3, and a cleaning section 4 by partition walls 1a and 1b. Has been. The polishing apparatus has an operation control unit 5 that controls the wafer processing operation.

  The load / unload unit 2 includes a front load unit 20 on which a substrate cassette for stocking a large number of wafers (substrates) is placed. A traveling mechanism 21 is laid along the front load section 20 in the load / unload section 2, and a transport robot (loader) 22 that can move along the arrangement direction of the substrate cassettes on the traveling mechanism 21. Is installed. The transfer robot 22 can access the substrate cassette mounted on the front load unit 20 by moving on the traveling mechanism 21.

  The polishing unit 3 is a region where a wafer is polished, and includes a first polishing unit 3A, a second polishing unit 3B, a third polishing unit 3C, and a fourth polishing unit 3D. As shown in FIG. 1, the first polishing unit 3A includes a first polishing table 30A to which a polishing pad 10 having a polishing surface is attached, and holds the wafer and presses the wafer against the polishing pad 10 on the polishing table 30A. A polishing head 31A for polishing while polishing, a first polishing liquid supply nozzle 32A for supplying a polishing liquid (for example, slurry) and a dressing liquid (for example, pure water) to the polishing pad 10, and a polishing surface of the polishing pad 10 A first dresser 33A for performing dressing, and a first atomizer 34A that sprays a mixed fluid of a liquid (for example, pure water) and a gas (for example, nitrogen gas) in a mist shape onto the polishing surface.

  Similarly, the second polishing unit 3B includes a second polishing table 30B to which the polishing pad 10 is attached, a polishing head 31B, a second polishing liquid supply nozzle 32B, a second dresser 33B, and a second atomizer 34B. The third polishing unit 3C includes a third polishing table 30C to which the polishing pad 10 is attached, a polishing head 31C, a third polishing liquid supply nozzle 32C, a third dresser 33C, and a third atomizer 34C. The fourth polishing unit 3D includes a fourth polishing table 30D to which the polishing pad 10 is attached, a polishing head 31D, a fourth polishing liquid supply nozzle 32D, a fourth dresser 33D, and a fourth atomizer 34D. And.

  As will be described later, the four polishing heads 31A, 31B, 31C, and 31D have different configurations, but the first polishing unit 3A, the second polishing unit 3B, the third polishing unit 3C, and the fourth polishing head. The unit 3D basically has the same configuration as a whole. Hereinafter, the first polishing unit 3A will be described with reference to FIG. FIG. 2 is a perspective view schematically showing the first polishing unit 3A. In FIG. 2, the dresser 33A and the atomizer 34A are omitted.

  The polishing table 30A is connected to a table motor 19 disposed below the table shaft 30a, and the table motor 19 rotates the polishing table 30A in the direction indicated by the arrow. A polishing pad 10 is affixed to the upper surface of the polishing table 30A, and the upper surface of the polishing pad 10 constitutes a polishing surface 10a for polishing the wafer W. The polishing head 31A is connected to the lower end of the head shaft 16A. The polishing head 31A is configured to hold the wafer W on the lower surface thereof by vacuum suction. The head shaft 16A is moved up and down by a vertical movement mechanism (not shown in FIG. 2).

  The polishing of the wafer W is performed as follows. The polishing head 31A and the polishing table 30A are rotated in directions indicated by arrows, respectively, and a polishing liquid (slurry) is supplied onto the polishing pad 10 from the polishing liquid supply nozzle 32A. In this state, the polishing head 31 </ b> A presses the wafer W against the polishing surface 10 a of the polishing pad 10. The surface of the wafer W is polished by the mechanical action of abrasive grains contained in the polishing liquid and the chemical action of the polishing liquid. After the polishing is completed, dressing (conditioning) of the polishing surface 10a is performed by the dresser 33A, and a high-pressure fluid is supplied from the atomizer 34A to the polishing surface 10a to remove polishing debris and abrasive grains remaining on the polishing surface 10a. Is done.

  Returning to FIG. 1, a first linear transporter 6 is disposed adjacent to the first polishing unit 3A and the second polishing unit 3B. The first linear transporter 6 is a mechanism for transferring a wafer between four transfer positions (first transfer position TP1, second transfer position TP2, third transfer position TP3, and fourth transfer position TP4). Further, the second linear transporter 7 is disposed adjacent to the third polishing unit 3C and the fourth polishing unit 3D. The second linear transporter 7 is a mechanism for transporting a wafer between three transport positions (fifth transport position TP5, sixth transport position TP6, and seventh transport position TP7).

  The wafer is transferred to the polishing units 3A and 3B by the first linear transporter 6. The polishing head 31A of the first polishing unit 3A moves between the upper position of the polishing table 30A and the second transport position TP2 by the swing operation. Therefore, the transfer of the wafer between the polishing head 31A and the first linear transporter 6 is performed at the second transfer position TP2.

  Similarly, the polishing head 31B of the second polishing unit 3B moves between the upper position of the polishing table 30B and the third transfer position TP3, and the wafer is transferred between the polishing head 31B and the first linear transporter 6. Is performed at the third transfer position TP3. The polishing head 31C of the third polishing unit 3C moves between the upper position of the polishing table 30C and the sixth transfer position TP6, and wafer transfer between the polishing head 31C and the second linear transporter 7 is the sixth. This is performed at the transfer position TP6. The polishing head 31D of the fourth polishing unit 3D moves between the upper position of the polishing table 30D and the seventh transport position TP7, and wafer transfer between the polishing head 31D and the second linear transporter 7 is the seventh. This is performed at the transfer position TP7.

  A lifter 11 for receiving a wafer from the transfer robot 22 is disposed adjacent to the first transfer position TP1. The wafer is transferred from the transfer robot 22 to the first linear transporter 6 through the lifter 11. A shutter (not shown) is provided between the lifter 11 and the transfer robot 22 on the partition wall 1a. When the wafer is transferred, the shutter is opened so that the wafer is transferred from the transfer robot 22 to the lifter 11. It has become.

  A swing transporter 12 is disposed between the first linear transporter 6, the second linear transporter 7, and the cleaning unit 4. Wafer transport from the first linear transporter 6 to the second linear transporter 7 is performed by the swing transporter 12. The wafer is transferred to the third polishing unit 3C and / or the fourth polishing unit 3D by the second linear transporter 7.

  On the side of the swing transporter 12, a temporary placement table 72 for a wafer installed on a frame (not shown) is disposed. As shown in FIG. 1, the temporary placement table 72 is disposed adjacent to the first linear transporter 6, and is positioned between the first linear transporter 6 and the cleaning unit 4. The swing transporter 12 moves between the fourth transport position TP4, the fifth transport position TP5, and the temporary placement table 72.

  The wafer placed on the temporary placement table 72 is transferred to the cleaning unit 4 by the first transfer robot 77 of the cleaning unit 4. As shown in FIG. 1, the cleaning unit 4 includes a first cleaning unit 73 and a second cleaning unit 74 that clean the polished wafer with a cleaning liquid, and a drying unit 75 that dries the cleaned wafer. Yes. The first transfer robot 77 operates to transfer the wafer from the temporary placement table 72 to the first cleaning unit 73 and further transfer the wafer from the first cleaning unit 73 to the second cleaning unit 74. A second transfer robot 78 is arranged between the second cleaning unit 74 and the drying unit 75. The second transfer robot 78 operates to transfer the wafer from the second cleaning unit 74 to the drying unit 75.

  Next, the operation of the polishing apparatus will be described. The transfer robot 22 takes out the wafer from the substrate cassette and passes it to the first linear transporter 6, and the wafer further passes through the first linear transporter 6 and / or the second linear transporter 7 to the polishing units 3 </ b> A to 3 </ b> D. Conveyed to at least two of them. The wafer is polished by at least two of the polishing units 3A to 3D.

  The polished wafer is transferred to the first cleaning unit 73 and the second cleaning unit 74 via the first linear transporter 6 and / or the second linear transporter 7, the swing transporter 12, and the transfer robot 77. The polished wafer is sequentially cleaned by the first cleaning unit 73 and the second cleaning unit 74. Further, the cleaned wafer is transferred to the drying unit 75 by the transfer robot 78, where the cleaned wafer is dried.

  The dried wafer is taken out from the drying unit 75 by the transfer robot 22 and returned to the substrate cassette on the front load unit 20. In this way, a series of processes including polishing, cleaning, and drying are performed on the wafer.

  The transfer robot 22, the first linear transporter 6, the second linear transporter 7, the swing transporter 12, and the transfer robots 77 and 78 are transfer apparatuses that transfer the wafer to at least two of the polishing units 3A to 3D. Configure. The operation of the transport device is controlled by the operation control unit 5. The transfer device transfers the wafer to at least two of the four polishing units 3A, 3B, 3C, and 3D according to a predetermined transfer path.

  The four polishing heads 31A, 31B, 31C, 31D have different configurations. Hereinafter, the polishing heads 31A, 31B, 31C, and 31D will be described. FIG. 3 is a cross-sectional view showing the polishing head 31A. The polishing head 31 </ b> A includes a rigid body 101 having a circular flat surface 101 a, a circular wafer holding material (substrate holding material) 103 that is attached to the flat surface 101 a and presses the wafer W against the polishing pad 10, and is not attached to the polishing pad 10. And a guide ring 105 for holding the substrate by contact. The wafer holding material (substrate holding material) 103 is also called a backing film.

  The rigid body 101 is connected to the lower end of the head shaft 16A via a universal joint 110. Therefore, the entire polishing head 31A can freely tilt with respect to the head shaft 16A. The head shaft 16 </ b> A is connected to the vertical movement mechanism 120. The vertical movement mechanism 120 is configured to raise and lower the head shaft 16A and the polishing head 31A, and to generate a predetermined downward load. As the vertical movement mechanism 120, an air cylinder or a combination of a servo motor and a ball screw mechanism is used.

  The circular wafer holder 103 is in contact with the back surface of the wafer W (that is, the surface opposite to the surface to be polished). In this state, when the vertical movement mechanism 120 transmits a downward load to the polishing head 31A through the head shaft 16A, the polishing head 31A presses the surface to be polished of the wafer W against the polishing pad 10. The polishing pressure is transmitted from the flat surface 101 a (lower surface) of the rigid body 101 to the wafer W via the wafer holding member 103. Hereinafter, the polishing head 31A may be referred to as a rigid polishing head.

  FIG. 4 is a cross-sectional view showing the polishing head 31B. The polishing head 31B includes a disk-shaped carrier 201, a plate 209 disposed below the carrier 201, and a circular flexible elastic membrane (membrane) 203 that forms a single pressure chamber P1 under the plate 209. And a retainer ring 205 that is fixed to the carrier 201 so as to surround the wafer W and presses the polishing pad 10. The elastic film 203 is attached to the plate 209, and the pressure chamber P1 is formed between the plate 209 and the elastic film 203. The pressure chamber P <b> 1 is connected to the fluid line 231, and pressurized gas (for example, pressurized air) whose pressure is adjusted is supplied into the pressure chamber P <b> 1 through the fluid line 231. A vacuum line 232 is connected to the fluid line 231, and a negative pressure is formed in the pressure chamber P <b> 1 by the vacuum line 232.

  The retainer ring 205 is fixed to the lower surface of the carrier 201. The carrier 201 is connected to the lower end of the head shaft 16B via a universal joint 210. Therefore, the carrier 201 and the retainer ring 205 can freely tilt with respect to the head shaft 16B. The head shaft 16B is connected to the vertical movement mechanism 235. The vertical movement mechanism 235 is configured to raise and lower the head shaft 16B and the polishing head 31B, and to generate a predetermined downward load. As the vertical movement mechanism 235, an air cylinder or a combination of a servo motor and a ball screw mechanism is used. When the vertical movement mechanism 235 transmits a downward load to the polishing head 31B through the head shaft 16B, the retainer ring 205 presses the polishing pad 10.

  The carrier 201 and the plate 209 are connected by an annular diaphragm 220, and a pressure chamber P2 is formed between the carrier 201 and the plate 209. The pressure chamber P <b> 2 is connected to the fluid line 238, and pressurized gas (for example, pressurized air) whose pressure is adjusted is supplied into the pressure chamber P <b> 2 through the fluid line 238. In addition, a vacuum line 239 is connected to the fluid line 238, and a negative pressure is formed in the pressure chamber P2 by the vacuum line 239. As the pressure in the pressure chamber P2 changes, the entire plate 209 and the elastic film 203 can move in the vertical direction.

  As can be seen from FIG. 4, since the plate 209 is connected to the carrier 201 via the diaphragm 220, the plate 209, the elastic film 203, and the wafer W can be flexibly tilted with respect to the carrier 201 and the retainer ring 205. Is possible. The lower surface of the elastic film (membrane) 203 is in contact with the back surface of the wafer W (that is, the surface opposite to the surface to be polished), and the elastic film 203 presses the surface to be polished of the wafer W against the polishing pad 10. The polishing pressure is generated by the pressure in the pressure chamber P1, and this polishing pressure is transmitted from the elastic film 203 to the wafer W. Hereinafter, the polishing head 31B may be referred to as a single chamber polishing head.

  The rigid polishing head 31A and the single chamber polishing head 31B described above are isobaric polishing heads that apply a uniform polishing pressure to the entire surface of the wafer W. These isobaric polishing heads 31A and 31B have a relatively simple structure and can be maintained at a low cost. For example, in the rigid polishing head 31A, the guide ring 105 does not contact the polishing pad 10 and thus does not wear. Further, since the polishing head 31A has a simple configuration using the wafer holding material 103, the cost is low. Since the polishing head 31B has few pressure chambers, the initial cost and the maintenance cost are reduced.

  FIG. 5 is a cross-sectional view showing the polishing head 31C. The polishing head 31C includes a disk-shaped carrier 301, a plate 309 disposed below the carrier 301, and a circular flexible elastic film that forms a plurality of pressure chambers C1, C2, C3, and C4 below the plate 309. (Membrane) 303 and a retainer ring 305 that is fixed to the carrier 301 so as to surround the wafer W and presses the polishing pad 10. The elastic film 303 is attached to the plate 309, and the pressure chambers C1, C2, C3, and C4 are formed between the elastic film 303 and the plate 309.

  The elastic membrane 303 has a plurality of annular partition walls 303a, and the pressure chambers C1, C2, C3, and C4 are partitioned from each other by the partition walls 303a. The central pressure chamber C1 is circular, and the other pressure chambers C2, C3, C4 are circular. These pressure chambers C1, C2, C3 and C4 are arranged concentrically. The polishing head 31C only needs to have at least two pressure chambers, and the number of pressure chambers is not particularly limited.

  The pressure chambers C1, C2, C3, and C4 are connected to the fluid lines F1, F2, F3, and F4, and pressurized gas (for example, pressurized air) whose pressure is adjusted passes through the fluid lines F1, F2, F3, and F4. The pressure chambers C1, C2, C3 and C4 are supplied. Vacuum lines V1, V2, V3, and V4 are connected to the fluid lines F1, F2, F3, and F4, and negative pressure is formed in the pressure chambers C1, C2, C3, and C4 by the vacuum lines V1, V2, V3, and V4. It has come to be. The internal pressures of the pressure chambers C1, C2, C3, C4 can be changed independently of each other, so that the corresponding four regions of the wafer W, namely the central part, the inner intermediate part, the outer intermediate part, In addition, the polishing pressure for the peripheral edge can be adjusted independently.

  The carrier 301 and the plate 309 are connected by an annular diaphragm 320, and a pressure chamber C5 is formed between the carrier 301 and the plate 309. The pressure chamber C5 is connected to the fluid line F5, and pressurized gas (for example, pressurized air) whose pressure is adjusted is supplied into the pressure chamber C5 through the fluid line F5. Further, a vacuum line V5 is connected to the fluid line F5, and a negative pressure is formed in the pressure chamber C5 by the vacuum line V5. As the pressure in the pressure chamber C5 changes, the entire plate 309 and the elastic film 303 can move in the vertical direction.

  The retainer ring 305 is fixed to the lower surface of the carrier 301. The carrier 301 is connected to the lower end of the head shaft 16C through a universal joint 310. Therefore, the carrier 301 and the retainer ring 305 can freely tilt with respect to the head shaft 16C. As can be seen from FIG. 5, since the plate 309 is connected to the carrier 301 via the diaphragm 320, the plate 309, the elastic film 303, and the wafer W can be flexibly tilted with respect to the carrier 301 and the retainer ring 305. Is possible.

  The head shaft 16C is connected to a vertical movement mechanism 325. The vertical movement mechanism 325 is configured to raise and lower the head shaft 16C and the polishing head 31C, and to generate a predetermined downward load. As the vertical movement mechanism 325, an air cylinder or a combination of a servo motor and a ball screw mechanism is used. When the vertical movement mechanism 325 transmits a downward load to the polishing head 31C through the head shaft 16C, the retainer ring 305 presses the polishing pad 10. During polishing of the wafer W, the elastic film 303 presses the wafer W against the polishing pad 10 while the retainer ring 305 presses the polishing pad 10 around the wafer W. Hereinafter, the polishing head 31C may be referred to as a first multi-chamber polishing head.

  FIG. 6 is a cross-sectional view showing the polishing head 31D. The polishing head 31D surrounds the wafer W with a disk-shaped carrier 401, a circular flexible elastic film (membrane) 403 that forms a plurality of pressure chambers D1, D2, D3, D4 below the carrier 401, and the wafer W. And a retainer ring 405 for pressing the polishing pad 10. The pressure chambers D1, D2, D3, D4 are formed between the elastic film 403 and the lower surface of the carrier 401.

  The elastic membrane 403 has a plurality of annular partition walls 403a, and the pressure chambers D1, D2, D3, and D4 are partitioned from each other by the partition walls 403a. The central pressure chamber D1 is circular, and the other pressure chambers D2, D3, D4 are circular. These pressure chambers D1, D2, D3, D4 are arranged concentrically. The polishing head 31D only needs to have at least two pressure chambers, and the number of pressure chambers is not particularly limited.

  The pressure chambers D1, D2, D3, and D4 are connected to the fluid lines G1, G2, G3, and G4, and pressurized gas (for example, pressurized air) whose pressure is adjusted passes through the fluid lines G1, G2, G3, and G4. The pressure chambers D1, D2, D3, and D4 are supplied. Vacuum lines U1, U2, U3, U4 are connected to the fluid lines G1, G2, G3, G4, and the vacuum lines U1, U2, U3, U4 form negative pressure in the pressure chambers D1, D2, D3, D4. It has come to be. The internal pressures of the pressure chambers D1, D2, D3, D4 can be changed independently of each other, so that the corresponding four regions of the wafer W, namely the central part, the inner intermediate part, the outer intermediate part, In addition, the polishing pressure for the peripheral edge can be adjusted independently.

  An annular elastic film 406 is disposed between the retainer ring 405 and the carrier 401. An annular pressure chamber D5 is formed in the elastic film 406. The pressure chamber D5 is connected to the fluid line G5, and pressurized gas (for example, pressurized air) whose pressure has been adjusted is supplied into the pressure chamber D5 through the fluid line G5. Further, a vacuum line U5 is connected to the fluid line G5, and a negative pressure is formed in the pressure chamber D5 by the vacuum line U5. As the pressure in the pressure chamber D5 changes, the entire retainer ring 405 can move in the vertical direction. The pressure in the pressure chamber D5 is applied to the retainer ring 405, and the retainer ring 405 is configured to directly press the polishing pad 10 independently of the elastic membrane (membrane) 403. During polishing of the wafer W, the elastic film 403 presses the wafer W against the polishing pad 10 while the retainer ring 405 presses the polishing pad 10 around the wafer W.

  The carrier 401 is fixed to the lower end of the head shaft 16D, and the carrier 401 and the retainer ring 405 cannot tilt with respect to the head shaft 16D. The head shaft 16D is connected to the vertical movement mechanism 410. The vertical movement mechanism 410 is configured to raise and lower the head shaft 16D and the polishing head 31D, and to position the polishing head 31D at a predetermined height. As the vertical movement mechanism 410 that functions as the polishing head positioning mechanism, a combination of a servo motor and a ball screw mechanism is used. The height of the polishing head 31D is the height from the polishing surface (upper surface) 10a of the polishing pad 10.

  The vertical movement mechanism 410 positions the polishing head 31D at a predetermined height, and in this state, pressurized gas is supplied to the pressure chambers D1 to D5. The elastic film 403 receives the pressure in the pressure chambers D1 to D4 and presses the wafer W against the polishing pad 10, and the retainer ring 405 receives the pressure in the pressure chamber D5 and presses the polishing pad 10. In this state, the wafer W is polished. Hereinafter, the polishing head 31D may be referred to as a second multi-chamber polishing head.

  The first multi-chamber polishing head 31C and the second multi-chamber polishing head 31D described above have a complicated configuration, but the above-described isobaric polishing heads 31A and 31B are more specific in that the polishing of the wafer W can be precisely controlled. Is also excellent. However, since the multi-chamber polishing heads 31C and 31D include a plurality of pressure chambers, the cost of the elastic membranes (membranes) 303 and 403 is high. Furthermore, the maintenance cost is high due to the complicated structure. The polishing apparatus according to the present embodiment includes not only the high performance multi-chamber polishing heads 31C and 31D but also the isobaric polishing heads 31A and 31B whose initial costs and maintenance costs are low. In addition, the processing cost of the wafer W can be reduced.

  Furthermore, by selecting a polishing head to be used according to the processing type of the wafer W, it is possible to extend the life of the polishing head and reduce the maintenance cost. The polishing heads 31A and 31B shown in FIGS. 3 and 4 are preferably used for rough polishing and finish polishing of the wafer W. In rough polishing of the wafer W, the wafer W is polished at a high polishing rate (high removal rate). In such rough polishing, the wear of the retainer ring is fast. By using the polishing heads 31A and 31B for rough polishing, the frequency of use of the polishing heads 31C and 31D can be reduced. As a result, the maintenance frequency of the polishing heads 31C and 31D having a high maintenance cost can be reduced, and the total maintenance cost can be reduced. The rigid polishing head 31A shown in FIG. 3 is particularly suitable for finish polishing of the wafer W. This is because the guide ring 105 does not come into contact with the polishing pad 10, so that abrasion powder of the guide ring 105 is not generated during polishing of the wafer W.

  In finish polishing, it is usually not necessary to perform wafer profile control. Therefore, it is not necessary to use the polishing heads 31C and 31D having a plurality of pressure chambers capable of controlling the wafer profile. Therefore, by using the polishing heads 31A and 31B for finish polishing, the maintenance frequency of the polishing heads 31C and 31D can be reduced, and the total maintenance cost can be reduced.

  Hereinafter, an example of polishing a wafer using at least two of the four different types of polishing heads 31A, 31B, 31C, and 31D will be described with reference to FIG. In FIG. 7, four polishing heads 31A, 31B, 31C, and 31D are used to perform rough polishing of the wafer, first profile control polishing of the wafer, second profile control polishing of the wafer, and finish polishing of the wafer in this order. It is a figure which shows an example. In this example, the wafer is conveyed in the order of the first polishing unit 3A, the third polishing unit 3C, the fourth polishing unit 3D, and the second polishing unit 3B. In the first polishing unit 3A, rough polishing of the wafer is performed using the polishing head 31A, and in the third polishing unit 3C, first profile control polishing of the wafer is performed using the polishing head 31C, and the fourth polishing unit 3D. Then, the second profile control polishing of the wafer is performed using the polishing head 31D, and the final polishing of the wafer is performed using the polishing head 31B in the second polishing unit 3B.

  The second profile controlled polishing is performed for fine correction of the wafer profile obtained by the first profile controlled polishing. In order to ensure the effect of the second profile controlled polishing, the arrangement of the pressure chambers of the second multi-chamber polishing head 31D is preferably different from the arrangement of the pressure chambers of the first multi-chamber polishing head 31C. This is for pressing the location of the wafer to which pressure in the pressure chambers C1 to C4 of the polishing head 31C is not so much applied by the pressure chambers D1 to D4 of the polishing head 31D. This point will be described with reference to FIGS. 8A and 8B.

  FIG. 8A is a schematic diagram showing a part of the pressure chambers C1 to C4 of the first multi-chamber polishing head 31C and a part of the corresponding wafer profile. As shown in FIG. 8A, the pressure chambers C <b> 1 and C <b> 2 are partitioned by a partition wall 303 a of the elastic film 303. In this partition wall 303a, the pressure in the pressure chambers C1 and C2 is not easily applied to the wafer. For this reason, at the position corresponding to the partition wall 303a (that is, the boundary between the pressure chambers C1 and C2), the wafer polishing rate decreases. Therefore, in order to improve such a local decrease in the polishing rate, as shown in FIG. 8B, the polishing head is positioned at a position corresponding to the position of the boundary between the pressure chambers C1 and C2 of the polishing head 31C. A 31D pressure chamber D2 is arranged. According to such an arrangement, the pressure in the pressure chamber D2 of the polishing head 31D is applied to the portion of the wafer where the polishing rate is lowered, and the polishing rate can be increased.

  FIG. 9 is a schematic diagram showing an example of the arrangement of the pressure chambers C1, C2, C3, C4 of the first multi-chamber polishing head 31C and the arrangement of the pressure chambers D1, D2, D3, D4 of the second multi-chamber polishing head 31D. It is. As shown in FIG. 9, the arrangement of the pressure chambers of the first multi-chamber polishing head 31C is different from the arrangement of the pressure chambers of the second multi-chamber polishing head 31D. That is, the pressure chambers D1, D2, D3, and D4 of the second multi-chamber polishing head 31D are disposed at the boundary between the pressure chambers C1, C2, C3, and C4 of the first multi-chamber polishing head 31C. Since the arrangement of the pressure chambers is different in this way, one of the two polishing heads 31C and 31D can perform polishing for wafer profile correction or fine adjustment.

  The two polishing heads 31 </ b> C and 31 </ b> D can press different regions of the wafer against the polishing pad 10. That is, when two polishing heads 31C and 31D having pressure chambers with different arrangements are used, the same effect as that obtained when the number of pressure chambers in one polishing head is substantially increased can be obtained. Therefore, the profile of the wafer can be controlled more precisely.

  In order to adjust the profile more precisely in a certain area of the wafer, the pressure chambers D1, D2, D3, D4 may be concentrated in that area. FIG. 10 shows the arrangement of the pressure chambers D1, D2, D3, and D4 that can precisely adjust the peripheral edge (or edge) of the wafer, and FIG. 11 shows the precise profile adjustment of the intermediate portion of the wafer. FIG. 12 shows the arrangement of the pressure chambers D1, D2, D3, D4 that can precisely adjust the profile of the center of the wafer. ing. As can be seen from FIGS. 10 to 12, at least two of the plurality of pressure chambers D1, D2, D3, D4 correspond to any one of the plurality of pressure chambers C1, C2, C3, C4. Placed in position.

  The combination and arrangement of the four different polishing heads 31A, 31B, 31C, 31D described above can be changed as appropriate. For example, as shown in FIG. 13, the rigid polishing head 31A is disposed in the first polishing unit 3A, the second multi-chamber polishing head 31D is disposed in the second polishing unit 3B, and the second multi-chamber polishing head 31D is third. The rigid polishing head 31A may be disposed in the polishing unit 3C, and the rigid polishing head 31A may be disposed in the fourth polishing unit 3D. In this example, two rigid polishing heads 31A and two second multi-chamber polishing heads 31D are used, and the single-chamber polishing head 31B and the first multi-chamber polishing head 31C are not used. As shown in FIG. 9, the arrangement of one of the two second multi-chamber polishing heads 31D is different from the arrangement of the pressure chambers of the other second multi-chamber polishing head 31D. Therefore, each of the two second multi-chamber polishing heads 31D can perform polishing for positively controlling (or generating) the wafer profile and polishing for fine adjustment of the wafer profile.

  One or both of the two rigid polishing heads 31A used in FIG. 13 may be replaced with a single chamber polishing head 31B. Further, one or both of the two second multi-chamber polishing heads 31D used in FIG. 13 may be replaced with the first multi-chamber polishing head 31C.

  An example of polishing a wafer using the combination of polishing heads shown in FIG. 13 will be described. FIG. 14 is a diagram illustrating an example of a combination of polishing heads selected according to a polishing target such as a wafer polishing amount, a wafer surface flattening request, and a scratch-free requirement. Example 1 shown in FIG. 14 shows an example of selecting a polishing head when the wafer polishing amount is large, the demand for flattening the wafer surface is high, and the demand for no defects is high. In Example 1, all four polishing heads of the four polishing units 3A, 3B, 3C, and 3D are used to polish the wafer.

  Example 2 shows a selection example of a polishing head when the amount of polishing of the wafer is small, the demand for flattening the wafer surface is high, and the demand for no defects is high. In Example 2, the rigid polishing head of the first polishing unit 3A is not used, but the second multi-chamber polishing head of the second polishing unit 3B, the second multi-chamber polishing head of the third polishing unit 3C, and the fourth polishing unit. A 3D rigid polishing head is used. Example 3 shows an example of selecting a polishing head when the amount of polishing of the wafer is small, the demand for flattening the wafer surface is low, and the demand for no defects is high. In Example 3, the rigid polishing head of the first polishing unit 3A and the second multi-chamber polishing head of the third polishing unit 3C are not used, but the second multi-chamber polishing head and the fourth polishing unit 3D of the second polishing unit 3B are used. Rigid body polishing heads are used. Example 4 shows an example of selecting a polishing head when the amount of polishing of the wafer is large, the demand for flattening the wafer surface is low, and the demand for no defects is low. In Example 4, the second multi-chamber polishing head of the third polishing unit 3C and the rigid polishing head of the fourth polishing unit 3D are not used, but the rigid polishing head of the first polishing unit 3A and the second of the second polishing unit 3B are used. A multi-chamber polishing head is used. Example 5 shows an example of selecting a polishing head when the amount of polishing of the wafer is small, the demand for flattening the wafer surface is high, and the demand for no defects is low. In Example 5, the rigid polishing heads of the first polishing unit 3A and the fourth polishing unit 3D are not used, and the second multi-chamber polishing heads of the second polishing unit 3B and the third polishing unit 3C are used.

  The embodiment described above is described for the purpose of enabling the person having ordinary knowledge in the technical field to which the present invention belongs to implement the present invention. Various modifications of the above embodiment can be naturally made by those skilled in the art, and the technical idea of the present invention can be applied to other embodiments. Accordingly, the present invention is not limited to the described embodiments, but is to be construed in the widest scope according to the technical idea defined by the claims.

DESCRIPTION OF SYMBOLS 1 Housing 2 Load / unload part 3 Polishing part 3A, 3B, 3C, 3D Polishing unit 4 Cleaning part 5 Operation control part 6 1st linear transporter 7 2nd linear transporter 10 Polishing pad 11 Lifter 12 Swing transporter 16 Head Shaft 19 Table motor 20 Front load part 21 Travel mechanism 22 Transfer robots 30A, 30B, 30C, 30D Polishing tables 31A, 31B, 31C, 31D Polishing heads 32A, 32B, 32C, 32D Polishing liquid supply nozzles 33A, 33B, 33C, 33D Dresser 34A, 34B, 34C, 34D Atomizer 72 Temporary stand 73 First cleaning unit 74 Second cleaning unit 75 Drying unit 77 First transfer robot 78 Second transfer robot

Claims (4)

A plurality of polishing tables for supporting each of the polishing pads;
A first polishing head having a plurality of pressure chambers for generating pressure for pressing a substrate against the polishing pad;
A second polishing head having a plurality of pressure chambers for generating pressure for pressing the substrate against the polishing pad;
An arrangement of the plurality of pressure chambers of the second polishing head is different from an arrangement of the plurality of pressure chambers of the first polishing head.   The plurality of pressure chambers of the second polishing head are arranged at positions corresponding to positions of boundaries between the plurality of pressure chambers of the first polishing head. Polishing equipment.   At least two of the plurality of pressure chambers of the second polishing head are disposed at positions corresponding to any one of the plurality of pressure chambers of the first polishing head. The polishing apparatus according to claim 1, wherein the polishing apparatus is characterized. Polishing the substrate by pressing the substrate against a polishing pad with a first polishing head having a plurality of pressure chambers;
A polishing method, comprising: polishing a substrate by pressing the substrate against a polishing pad with a second polishing head having a plurality of pressure chambers having different arrangements from the plurality of pressure chambers of the first polishing head.

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