JP2013157541A - Substrate holding device, polishing apparatus and polishing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a substrate holding device which can prevent foreign objects such as abrasion powder from falling onto a polished surface and allows a retainer ring to evenly apply a desired pressing force to the polished surface.SOLUTION: A substrate holding device comprises: an inner retainer ring 20 which is vertically movable independently of a top ring body 10 and is arranged to surround a substrate; an inner pressing mechanism 60 which presses the inner retainer ring 20 against a polished surface; an outer retainer ring 30 which is vertically movable independently of the inner retainer ring and the top ring body 10; an outer pressing mechanism 80 which presses the outer retainer ring 30 against the polished surface; and a support mechanism 111 which receives lateral force applied from the substrate to the inner retainer ring 20 during polishing of the substrate.

Description

  The present invention relates to a substrate holding device used in a polishing apparatus that polishes a substrate such as a wafer, and more particularly to a substrate holding device that holds a substrate and presses it against a polishing surface. The present invention also relates to a polishing apparatus and a polishing method using such a substrate holding apparatus.

  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.

Therefore, in the semiconductor device manufacturing process, planarization of the surface of the semiconductor device has become increasingly important. The most important technique for planarizing the surface is chemical mechanical polishing (CMP). In this chemical mechanical polishing, a polishing apparatus is used to perform polishing by supplying a polishing liquid containing abrasive grains such as silica (SiO ₂ ) onto the polishing surface of the polishing pad while sliding the wafer against the polishing surface. It is.

  This type of polishing apparatus includes a polishing table that supports a polishing pad, and a substrate holding device 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 of the polishing pad with a predetermined pressure while the wafer is held by the substrate holding apparatus. At this time, the wafer is brought into sliding contact with the polishing surface by moving the polishing table and the substrate holding device relative to each other, and the surface of the wafer is polished to a flat and mirror surface.

  If 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, insufficient polishing or overpolishing may occur depending on the pressing force applied to each part of the wafer. It will occur. Therefore, in order to make the pressing force on the wafer uniform, a pressure chamber formed of an elastic film is provided in the lower part of the substrate holding device, and fluid pressure such as air is supplied to the pressure chamber through the elastic film. The wafer is pressed by the above method.

  In this case, 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 polished, so-called “edge fringing” is caused. May end up. In order to prevent such edge fringing, a retainer ring for holding the outer peripheral edge of the wafer is provided so as to be movable up and down with respect to the top ring main body (or carrier head main body), and the polishing surface of the polishing pad located on the outer peripheral edge side of the wafer Is pressed by a retainer ring.

  During polishing, a frictional force is generated between the wafer and the polishing pad. This frictional force acts as a lateral (horizontal) force on the retainer ring. The substrate holding device disclosed in Patent Document 1 is configured to support this lateral force by a retainer ring guide disposed on the outer peripheral side of the retainer ring. However, since the point at which the retainer ring guide supports the retainer ring is separated from the polishing surface, the retainer ring that has received a lateral force from the wafer is tilted around this support point. For this reason, there exists a problem that a retainer ring cannot give a desired pressing force uniformly to a grinding | polishing surface. Further, the retainer ring may be locally deformed by the lateral force received from the wafer. Such a deformed portion prevents the retainer ring from applying a desired pressing force to the polishing surface.

  Further, in the substrate holding device described in Patent Document 1, since the outer surface of the retainer ring and the inner surface of the retainer ring guide are in sliding contact, wear powder is generated at the sliding contact portion. When the wear powder falls on the polishing surface, it causes a wafer defect. Therefore, an elastic sheet is installed to prevent the wear powder from dropping onto the polishing surface. However, if the retainer ring fulcrum (that is, the contact point between the retainer ring and the retainer ring guide) is lowered to suppress the inclination of the retainer ring, this elastic sheet cannot be installed, and the wear powder falls on the polished surface. Resulting in.

  In the substrate holding device disclosed in Patent Document 2, the retainer ring guide shown in Patent Document 1 is not installed on the outer peripheral side of the retainer ring, and the lateral force applied from the wafer to the retainer ring is above the center of the wafer. It is configured to be supported by a spherical bearing provided. Therefore, no wear powder is generated on the outer peripheral side of the retainer ring, and the wear powder does not fall onto the polishing surface.

  However, since the spherical bearing is located away from the polishing surface, the retainer ring that receives a lateral force from the wafer is tilted around the spherical bearing, and as a result, the retainer ring uniformly achieves the desired pressing force. There is a problem that it cannot be applied to the polished surface. Further, there is a problem that the retainer ring is locally deformed by a lateral force received from the wafer, and the retainer ring cannot apply a desired pressing force to the polishing surface.

JP 2007-268654 A JP 2009-190101 A

  The present invention has been made to solve the above-described problems, and prevents a foreign substance such as abrasion powder from falling on the polishing surface, and the retainer ring can uniformly apply a desired pressing force to the polishing surface. An object is to provide a holding device. Another object of the present invention is to provide a polishing apparatus and a polishing method using such a substrate holding apparatus.

  In order to achieve the above-described object, the first aspect of the present invention is a top ring body that holds an elastic film for pressing the substrate against the polishing surface, and the top ring body can be moved up and down independently. An inner retainer ring disposed so as to surround the substrate, an inner pressing mechanism that presses the inner retainer ring against the polishing surface, and a radially outer side of the inner retainer ring. An outer retainer ring that can move up and down independently of the ring and the top ring body, an outer pressing mechanism that presses the outer retainer ring against the polishing surface, and the inner retainer ring from the substrate during polishing of the substrate And receiving the lateral force applied to the outer retainer ring from the inner retainer ring. A substrate holding device characterized by comprising a support mechanism that does not allow the transfer of the transverse forces to the grayed.

  According to a second aspect of the present invention, there is provided a top ring body that holds an elastic film for pressing the substrate against the polishing surface, a retainer ring that is disposed so as to surround the substrate and is in contact with the polishing surface, and the retainer ring And a spherical bearing for supporting the tilting of the retainer ring, wherein the center of tilting of the retainer ring is below the spherical bearing.

  According to a third aspect of the present invention, there is provided a top ring body that holds an elastic film for pressing the substrate against the polishing surface, an inner retainer ring that is disposed so as to surround the substrate and is in contact with the polishing surface, and the inner A substrate holding apparatus comprising: an outer retainer ring that is provided on a radially outer side of the retainer ring and that contacts the polishing surface; and a barrier seal that closes a gap between the inner retainer ring and the outer retainer ring. is there.

According to a fourth aspect of the present invention, there is provided a polishing apparatus comprising the substrate holding apparatus and a polishing table that supports a polishing pad having a polishing surface.
According to a fifth aspect of the present invention, the polishing table supporting the polishing pad is rotated, the polishing liquid is supplied onto the polishing surface of the polishing pad, and the substrate is pressed against the polishing surface by the substrate holding device. A polishing method characterized by polishing a substrate.

  According to the first aspect of the present invention described above, the outer retainer ring is separately disposed on the outer peripheral side of the inner retainer ring that receives a lateral force from the substrate. The inner retainer ring and the outer retainer ring can press the polishing surface independently of each other. The lateral force acting on the inner retainer ring is received by the support mechanism, and the lateral force that the inner retainer ring receives from the substrate during polishing of the substrate does not act on the outer retainer ring. Therefore, the inclination and local deformation of the outer retainer ring with respect to the polishing surface can be suppressed, and the outer retainer ring can give a desired pressing force to the polishing surface.

  According to the second aspect of the present invention described above, the tilting center of the retainer ring is located below the spherical bearing. Accordingly, the center of tilting of the retainer ring can be lowered and brought close to the polishing surface or close to the polishing surface. As a result, the moment of force acting on the retainer ring is zero or extremely small. Therefore, tilting of the retainer ring can be suppressed, and the retainer ring can uniformly apply a desired pressing force to the polishing surface. Furthermore, the retainer ring can be used as an inner retainer ring, and an outer retainer ring can be disposed on the outer peripheral side of the inner retainer ring. Since the outer retainer ring is configured not to receive a lateral force due to the frictional force between the substrate and the polishing surface, the outer retainer ring is not tilted or locally deformed with respect to the polishing surface. Therefore, the outer retainer ring can uniformly apply a desired pressing force to the polishing surface.

  According to the third aspect of the present invention described above, the outer retainer ring is disposed on the outer peripheral side of the inner retainer ring that receives a lateral force from the substrate. In the substrate holding apparatus provided with the inner retainer ring and the outer retainer ring, there are various sliding contact portions above the two retainer rings for transmitting the rotational driving force and the pressing force. Wear powder from these sliding contact portions may fall from the gap between the two retainer rings onto the polishing surface. Conversely, the polishing liquid (slurry) may enter the substrate holding device and hinder the operation of the substrate holding device. According to the third aspect of the present invention, the barrier seal is provided between the inner retainer ring and the outer retainer ring. This barrier seal prevents the wear powder from falling onto the polishing surface and prevents the polishing liquid from entering the substrate holding device.

It is a mimetic diagram showing the whole polisher composition provided with the substrate holding device (top ring) concerning one embodiment of the present invention. It is sectional drawing of the top ring shown by FIG. It is other sectional drawing of a top ring. FIG. 6 is still another cross-sectional view of the top ring. It is a top view of a top ring. It is the VI-VI sectional view taken on the line shown in FIG. It is the VII-VII sectional view taken on the line shown in FIG. It is the elements on larger scale of the top ring shown in FIG. It is an expanded sectional view of a spherical bearing. FIG. 10A is a diagram showing a state in which the shaft portion moves up and down with respect to the spherical bearing, and in FIG. 10B and FIG. 10C, the shaft portion tilts together with the intermediate wheel. It is a figure which shows a mode. Fig.11 (a) is the figure which looked at the inner retainer ring and the outer retainer ring from the bottom, and FIG.11 (b) is the XI-XI sectional view taken on the line shown to Fig.11 (a). FIG. 12A to FIG. 12C are diagrams showing examples of radial grooves provided on the lower surfaces of the inner retainer ring and the outer retainer ring, respectively. FIGS. 13A to 13C are diagrams showing other examples of radial grooves provided on the lower surfaces of the inner retainer ring and the outer retainer ring, respectively. FIG. 14A to FIG. 14C are diagrams showing still other examples of radial grooves provided on the lower surfaces of the inner retainer ring and the outer retainer ring, respectively. It is sectional drawing which shows the example which formed the through-hole in the outer retainer ring.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding components are denoted by the same reference numerals, and redundant description is omitted.
FIG. 1 is a schematic diagram showing an overall configuration of a polishing apparatus provided with a substrate holding device according to an embodiment of the present invention. As shown in FIG. 1, the polishing apparatus includes a polishing table 3 that supports a polishing pad 2, and a top ring 1 as a substrate holding device that holds a wafer W that is an object to be polished and presses it against the polishing pad 2. ing.

  The polishing table 3 is connected to a motor (not shown) arranged below the table shaft 3a, and is rotatable around the table shaft 3a. The polishing pad 2 is affixed to the upper surface of the polishing table 3, and the upper surface 2 a of the polishing pad 2 constitutes a polishing surface for polishing the wafer W. A polishing liquid supply mechanism 5 is installed above the polishing table 3, and the polishing liquid is supplied onto the polishing pad 2 by the polishing liquid supply mechanism 5.

  The top ring 1 is connected to a top ring shaft 7, and the top ring shaft 7 is moved up and down by a vertical movement mechanism (not shown) installed in the top ring head 8. By the vertical movement of the top ring shaft 7, the entire top ring 1 is moved up and down as shown by an arrow with respect to the top ring head 8 and positioned. Further, the top ring shaft 7 is rotated by a rotation mechanism (not shown) installed in the top ring head 8. Accordingly, the top ring 1 rotates around its own axis as indicated by the arrow as the top ring shaft 7 rotates. A well-known technique can be used for the vertical movement mechanism and rotation mechanism of the top ring 1 described above.

  The top ring 1 and the polishing table 3 rotate as indicated by arrows, and in this state, the top ring 1 presses the wafer W against the polishing surface 2 a of the polishing pad 2. The polishing liquid is supplied onto the polishing pad 2 from the polishing liquid supply mechanism 5, and the wafer W is polished by sliding contact with the polishing pad 2 in a state where the polishing liquid exists between the polishing pad 2 and the wafer W. .

  Next, the top ring 1 constituting the substrate holding device will be described. FIGS. 2 to 4 are views showing the top ring 1 that holds the wafer W as an object to be polished and presses it against the polishing surface 2a of the polishing pad 2 on the polishing table 3, and is cut along a plurality of radial directions. FIG. 5 is a plan view of the top ring 1, FIG. 6 is a sectional view taken along line VI-VI shown in FIG. 2, and FIG. 7 is a sectional view taken along line VII-VII shown in FIG.

  The top ring 1 includes a top ring body 10 that presses the wafer W against the polishing surface 2 a, an inner retainer ring 20 that is disposed so as to surround the wafer W, and an outer that is disposed so as to surround the inner retainer ring 20. A retainer ring 30 is provided. The top ring body 10, the inner retainer ring 20, and the outer retainer ring 30 are configured to rotate integrally with the rotation of the top ring shaft 7. The inner retainer ring 20 is located on the radially outer side of the top ring body 10, and the outer retainer ring 30 is located on the radially outer side of the inner retainer ring 20. The inner retainer ring 20 is configured to be movable up and down independently of the top ring body 10 and the outer retainer ring 30. Further, the outer retainer ring 30 is configured to be movable up and down independently of the top ring body 10 and the inner retainer ring 20.

  The top ring body 10 includes a circular flange 41, a spacer 42 attached to the lower surface of the flange 41, and a carrier 43 attached to the lower surface of the spacer 42. The flange 41 is connected to the top ring shaft 7 by a bolt (not shown). As shown in FIG. 4, the spacer 42 is fixed to the flange 41 by the bolt 15, and the carrier 43 is fixed to the spacer 42 by the maintenance bolt 16. FIG. 4 shows a state in which the maintenance bolt 16 is detached from the carrier 43. The top ring body 10 including the flange 41, the spacer 42, and the carrier 43 is formed of a resin such as engineering plastic (for example, PEEK). The flange 41 may be made of a metal such as SUS or aluminum.

  An elastic film 45 that is in contact with the back surface of the wafer W is attached to the lower surface of the carrier 43. The elastic film 45 is attached to the lower surface of the carrier 43 by an annular edge holder 50 and annular ripple holders 51 and 52. The edge holder 50 is disposed on the outer periphery of the carrier 43, and the ripple holders 51 and 52 are disposed on the inner side of the edge holder 50. The elastic film 45 is formed of a rubber material having excellent strength and durability, such as ethylene propylene rubber (EPDM), polyurethane rubber, and silicon rubber.

  FIG. 8 is an enlarged cross-sectional view of the inner retainer ring 20 and the outer retainer ring 30 shown in FIG. As shown in FIG. 8, the inner retainer ring 20 is disposed on the outer peripheral portion of the top ring body 10. The inner retainer ring 20 includes an inner ring member 21 that comes into contact with the polishing surface 2a (see FIG. 1) of the polishing pad 2, and an inner drive ring 22 fixed to the upper portion of the inner ring member 21. The inner ring member 21 is coupled to the inner drive ring 22 by a plurality of bolts 24. The inner ring member 21 is disposed so as to surround the outer peripheral edge of the wafer W, and holds the wafer W so that the wafer W does not jump out of the top ring 1 during polishing of the wafer W.

  The upper part of the inner retainer ring 20 is connected to the inner pressing mechanism 60, and the inner pressing mechanism 60 causes the lower surface of the inner retainer ring 20 (that is, the lower surface of the inner ring member 21) to the polishing surface 2 a of the polishing pad 2. To be pressed. The inner drive ring 22 is made of a metal material such as SUS or ceramic, and the inner ring member 21 is made of a resin material such as PEEK or PPS.

  The inner pressing mechanism 60 includes an inner piston 61 fixed to the upper part of the inner drive ring 22, an inner rolling diaphragm 62 connected to the upper surface of the inner piston 61, and an inner cylinder 63 that houses the inner rolling diaphragm 62. Yes. The upper end of the inner rolling diaphragm 62 is held by a holding member 64, and this holding member 64 is fixed to the upper portion of the inner cylinder 63 by a bolt 65.

  The inner retainer ring 20 is detachably connected to the inner pressing mechanism 60. More specifically, the inner piston 61 is made of a magnetic material such as metal, and a plurality of magnets 68 are disposed on the inner drive ring 22. When these magnets 68 attract the inner piston 61, the inner retainer ring 20 is fixed to the inner piston 61 by a magnetic force. As the magnetic material of the inner piston 61, for example, corrosion-resistant magnetic stainless steel is used. The inner drive ring 22 may be formed of a magnetic material, and a magnet may be disposed on the inner piston 61.

  An inner pressure chamber 69 is formed inside the inner rolling diaphragm 62. The inner pressure chamber 69 is connected to a fluid supply source (not shown) via a flow path 70 (shown schematically). When pressurized fluid (for example, pressurized air) is supplied from the fluid supply source to the inner pressure chamber 69, the inner rolling diaphragm 62 pushes the inner piston 61 downward, and the inner piston 61 lowers the inner retainer ring 20 downward. Press down. Thus, the inner pressing mechanism 60 presses the lower surface of the inner retainer ring 20 (that is, the lower surface of the inner ring member 21) against the polishing surface 2a of the polishing pad 2. The inner pressure chamber 69 is further connected to a vacuum pump (not shown), and the inner retainer ring 20 can be raised by forming a negative pressure in the inner pressure chamber 69 by this vacuum pump. The inner pressure chamber 69 is also connected to an atmosphere release mechanism (not shown), and the inner pressure chamber 69 can be opened to the atmosphere.

  The outer retainer ring 30 is disposed so as to surround the inner retainer ring 20. The outer retainer ring 30 includes an outer ring member 31 that contacts the polishing surface 2 a of the polishing pad 2, and an outer drive ring 32 that is fixed to the upper portion of the outer ring member 31. The outer ring member 31 is coupled to the outer drive ring 32 by a plurality of bolts 34 (see FIG. 3). The outer ring member 31 is disposed so as to surround the inner ring member 21 of the inner retainer ring 20. A gap is formed between the inner ring member 21 and the outer ring member 31, and the inner ring member 21 and the outer ring member 31 are always kept in non-contact.

  The upper part of the outer retainer ring 30 is connected to an outer pressing mechanism 80, and the outer pressing mechanism 80 allows the lower surface of the outer retainer ring 30 (that is, the lower surface of the outer ring member 31) to the polishing surface 2 a of the polishing pad 2. To be pressed. The outer drive ring 32 is made of a metal material such as SUS or ceramic, and the outer ring member 31 is made of a resin material such as PEEK or PPS.

  The outer pressing mechanism 80 includes an outer piston 81 fixed to the upper portion of the outer drive ring 32, an outer rolling diaphragm 82 connected to the upper surface of the outer piston 81, and an outer cylinder 83 that houses the outer rolling diaphragm 82. Yes. The upper end of the outer rolling diaphragm 82 is held by a holding member 84, and this holding member 84 is fixed to the upper portion of the outer cylinder 83 by a bolt 85. In the present embodiment, the inner cylinder 63 and the outer cylinder 83 are integrally formed.

  The outer retainer ring 30 is detachably connected to the outer pressing mechanism 80. More specifically, the outer piston 81 is made of a magnetic material such as metal, and a plurality of magnets 88 are disposed on the upper part of the outer drive ring 32. When these magnets 88 attract the outer piston 81, the outer retainer ring 30 is fixed to the outer piston 81 by a magnetic force. The outer drive ring 32 may be formed of a magnetic material, and a magnet may be disposed on the outer piston 81.

  An outer pressure chamber 89 is formed inside the outer rolling diaphragm 82. The outer pressure chamber 89 is connected to the fluid supply source via a flow path 90 (shown schematically). When pressurized fluid (for example, pressurized air) is supplied to the outer pressure chamber 89 from this fluid supply source, the outer rolling diaphragm 82 pushes the outer piston 81 downward, and the outer piston 81 moves the outer retainer ring 30 downward. Press down. Thus, the outer pressing mechanism 80 presses the lower surface of the outer retainer ring 30 (that is, the lower surface of the outer ring member 31) against the polishing surface 2a of the polishing pad 2. The outer pressure chamber 89 is further connected to a vacuum pump, and the outer retainer ring 30 can be raised by forming a negative pressure in the outer pressure chamber 89 by this vacuum pump. The outer pressure chamber 89 is also connected to an atmosphere release mechanism (not shown), and the outer pressure chamber 89 can be opened to the atmosphere.

  During polishing of the wafer, the elastic film 45 presses the wafer W against the polishing surface 2 a of the polishing pad 2, and at the same time, the inner retainer ring 20 and the outer retainer ring 30 directly press the polishing surface 2 a of the polishing pad 2. The inner retainer ring 20 and the outer retainer ring 30 are configured to be able to move up and down independently with respect to the top ring body 10 and are connected to the inner pressing mechanism 60 and the outer pressing mechanism 80, respectively. Therefore, the inner pressing mechanism 60 and the outer pressing mechanism 80 can press the inner retainer ring 20 and the outer retainer ring 30 against the polishing surface 2a of the polishing pad 2 independently of each other.

  As shown in FIG. 2, the inner retainer ring 20 is connected to the spherical bearing 111 via the connecting member 100. The spherical bearing 111 is disposed on the inner side in the radial direction of the inner retainer ring 20. The connecting member 100 includes a shaft portion 101 that is disposed in the center portion of the top ring body 10 and extends in the vertical direction, and a plurality of spokes 102 that extend radially from the shaft portion 101. One end portion of the spoke 102 is fixed to the shaft portion 101 by a plurality of bolts 103, and the other end portion of the spoke 102 is fixed to the inner drive ring 22 of the inner retainer ring 20. In this embodiment, the spoke 102 and the inner drive ring 22 are integrally formed.

  The shaft portion 101 of the connecting member 100 is supported by a spherical bearing 111 disposed at the center portion of the top ring body 10 so as to be movable in the vertical direction. With such a configuration, the connecting member 100 and the inner retainer ring 20 fixed to the connecting member 100 are movable in the vertical direction with respect to the top ring body 10. A through hole 104 extending in the vertical direction is formed in the shaft portion 101. The through-hole 104 acts as an air vent hole when the shaft portion 101 moves in the vertical direction with respect to the spherical bearing 111, so that the inner retainer ring 20 can move smoothly in the vertical direction with respect to the top ring body 10. It has become.

  FIG. 9 is an enlarged cross-sectional view of the spherical bearing 111. As shown in FIG. 9, the spherical bearing 111 includes an intermediate wheel 114 connected to the inner retainer ring 20 via the connecting member 100, an outer wheel 113 that slidably supports the intermediate wheel 114 from above, and an intermediate wheel 114. The inner ring 115 is slidably supported from below. The intermediate ring 114 has a partial spherical shell shape smaller than the upper half of the spherical shell, and is sandwiched between the outer ring 113 and the inner ring 115.

  A recess 43a is formed at the center of the carrier 43, and the outer ring 113 is disposed in the recess 43a. The outer ring 113 has a collar 113a on the outer periphery thereof, and the outer ring 113 is fixed to the carrier 43 by fixing the collar 113a to the stepped portion of the recess 43a with a bolt (not shown). It is possible to apply pressure to the ring 114 and the inner ring 115. The inner ring 115 is disposed on the bottom surface of the recess 43a, and supports the intermediate ring 114 from below so that a gap is formed between the lower surface of the intermediate ring 114 and the bottom surface of the recess 43a.

  The inner surface 113b of the outer ring 113, the outer surface 114a and the inner surface 114b of the intermediate ring 114, and the outer surface 115a of the inner ring 115 are substantially hemispherical surfaces with the fulcrum O as the center. The outer surface 114 a of the intermediate wheel 114 is slidably in contact with the inner surface 113 b of the outer wheel 113, and the inner surface 114 b of the intermediate wheel 114 is slidably in contact with the outer surface 115 a of the inner wheel 115. The inner surface 113b (sliding contact surface) of the outer ring 113, the outer surface 114a and inner surface 114b (sliding contact surface) of the intermediate ring 114, and the outer surface 115a (sliding contact surface) of the inner ring 115 have partial spherical shapes smaller than the upper half of the spherical surface. Have. With such a configuration, the intermediate wheel 114 can tilt in all directions (360 °) with respect to the outer ring 113 and the inner ring 115, and the fulcrum O that is the center of tilting is located below the spherical bearing 111.

  The outer ring 113, the intermediate ring 114, and the inner ring 115 are formed with through holes 113c, 114c, and 115b into which the shaft portion 101 is inserted. A gap is formed between the through hole 113 c of the outer ring 113 and the shaft portion 101, and similarly, a gap is formed between the through hole 115 b of the inner ring 115 and the shaft portion 101. The through hole 114 c of the intermediate wheel 114 has a smaller diameter than the through holes 113 c and 115 b of the outer ring 113 and the inner ring 115, and the shaft portion 101 can move only in the vertical direction with respect to the intermediate wheel 114. . Accordingly, the inner retainer ring 20 connected to the shaft portion 101 is not substantially allowed to move in the lateral direction, and the position of the inner retainer ring 20 in the lateral direction (horizontal direction) is fixed by the spherical bearing 111. .

  10A shows a state in which the shaft portion 101 moves up and down with respect to the spherical bearing 111. FIGS. 10B and 10C show that the shaft portion 101 tilts together with the intermediate wheel 114. FIG. It shows how it is. As shown in FIG. 10A to FIG. 10C, the inner retainer ring 20 connected to the shaft portion 101 can be tilted around the fulcrum O integrally with the intermediate wheel 114, and On the other hand, it can move up and down.

  The spherical bearing 111 allows the inner retainer ring 20 to move up and down and tilt, while restricting the lateral movement (horizontal movement) of the inner retainer ring 20, so that the inner retainer ring 20 moves to the outer retainer ring 30. The transmission of the lateral force is not allowed. Accordingly, the spherical bearing 111 receives a lateral force (force directed outward in the radial direction of the wafer) that the inner retainer ring 20 receives from the wafer due to friction between the wafer and the polishing pad 2 during polishing of the wafer. It functions as a support mechanism that restricts the lateral movement of the inner retainer ring 20 (that is, fixes the horizontal position of the inner retainer ring 20).

  The inner retainer ring 20 is supported by the spherical bearing 111 so that it can tilt around the fulcrum O and can move up and down on an axis passing through the fulcrum O. The fulcrum O is preferably located as close as possible to the polishing surface 2a of the polishing pad 2 during polishing of the wafer (that is, the contact surface between the polishing pad 2 and the wafer). In the embodiment shown in FIG. 9, the fulcrum O is located slightly above the polishing surface 2a during polishing of the wafer. The position of the fulcrum O during wafer polishing is preferably −15 mm to 15 mm above the polishing surface 2a, and more preferably −5 mm to 5 mm. Here, −15 mm indicates a case where the fulcrum O is at a position 15 mm below the polishing surface 2a. Most preferably, the fulcrum O is on the polishing surface 2a of the polishing pad 2 during wafer polishing, that is, the distance between the fulcrum O and the polishing surface 2a is zero. This is because when the fulcrum O is on the polishing surface 2a, the frictional force between the wafer and the polishing surface 2a does not substantially act as a moment of force for tilting the inner retainer ring 20.

  By employing the spherical bearing 111 described above, the moment of the force for tilting the inner retainer ring 20 is zero or very small. Therefore, the inclination of the inner retainer ring 20 can be kept small, and the inner retainer ring 20 can uniformly apply a desired pressing force to the polishing surface 2a.

  According to the inner retainer ring 20 configured as described above and the spherical bearing 111 that supports the inner retainer ring 20, the inner retainer ring 20 is smoothly tilted by the spherical bearing 111 during the polishing of the wafer. During polishing of the wafer, a lateral (horizontal) force is applied from the wafer to the inner retainer ring 20 due to friction between the wafer and the polishing pad 2. This lateral force can be received by the spherical bearing 111 located above the center of the wafer, and the lateral movement of the inner retainer ring 20 is limited by the spherical bearing 111. Accordingly, no lateral force acts on the inner retainer ring 20 to the outer retainer ring 30, and the inclination of the outer retainer ring 30 with respect to the polishing surface is reduced. Further, unlike the inner retainer ring 20, the outer retainer ring 30 does not receive a force from the wafer, so that local deformation of the outer retainer ring 30 can be prevented. Therefore, the outer retainer ring 30 can uniformly apply a desired pressing force to the polishing surface 2a.

  The frictional force generated when the outer retainer ring 30 itself is in sliding contact with the polishing surface 2a is smaller than the frictional force generated between the wafer and the polishing surface 2a because the contact area between the outer retainer ring 30 and the polishing surface 2a is small. Is quite small. The frictional force acting on the outer retainer ring 30 is transmitted to the inner retainer ring 20 via a stopper 119 installed between the outer retainer ring 30 and the inner retainer ring 20, and finally the inner retainer ring 20. It is supported by a spherical bearing 111 which is a support mechanism. The stopper 119 has a ring shape and is attached to the outer peripheral surface of the inner drive ring 22. The stopper 119 may be attached to the inner peripheral surface of the outer drive ring 32. The stopper 119 is preferably made of a resin material having excellent slidability. The longitudinal sectional shape of the sliding surface of the stopper 119 may be a straight line or a curved line.

  It is preferable to use ceramic such as SiC or zirconia for at least one of the outer ring 113, the intermediate ring 114, the inner ring 115, and the shaft portion 101 of the connecting member 100 of the spherical bearing 111. In this case, only the sliding contact surface may be formed from ceramic. For example, the sliding contact surface of the outer ring 113 may be formed of ceramic, and the other part may be formed of metal. By using ceramic, the wear resistance of the sliding contact surface can be increased, and the surface roughness of the sliding contact surface can be reduced to reduce the friction of the sliding contact surface. Contains Teflon (registered trademark) with high self-lubricating property, low friction coefficient, and excellent wear resistance to reduce friction on the sliding surface of outer ring 113, intermediate ring 114, inner ring 115, and shaft 101 The coated film may be provided on the sliding surface. Furthermore, PTFE (tetrafluoroethylene), PEEK (polyether ether ketone), PPS (polyphenylene sulfide), or the like is formed on at least one sliding contact surface of the outer ring 113, the intermediate ring 114, the inner ring 115, and the shaft portion 101. A low friction material made of a resin material may be provided. Or you may comprise a sliding contact surface using the resin material which added fibers, such as carbon fiber, and a solid lubricant.

  For the outer ring 113, the intermediate ring 114, the inner ring 115, and the shaft portion 101, it is possible to use a metal material having a low friction coefficient and excellent wear resistance. However, when polishing a metal film formed on a wafer, an eddy current sensor may be used to measure the metal film thickness during polishing. In such a case, if a metal which is a conductive material is used for the spherical bearing 111 near the wafer, the measurement accuracy of the eddy current sensor may be lowered. For this reason, it is preferable to use a nonconductive material for the spherical bearing 111 and the shaft portion 101.

  The inner retainer ring 20 has a structure that can be tilted independently with respect to the top ring body 10 and the outer retainer ring 30. The spherical bearing 111 that supports the inner retainer ring 20 so as to be tiltable and vertically movable is provided inside the top ring main body 10 and accommodated in the concave portion 43a of the carrier 43. The wear powder is contained in the top ring body 10 and does not fall onto the polishing surface 2a.

  As shown in FIG. 8, a barrier seal 120 made of an annular elastic film is provided between the inner retainer ring 20 and the outer retainer ring 30. The barrier seal 120 is disposed over the entire circumference of the inner retainer ring 20 and the outer retainer ring 30 so as to close the gap between the inner retainer ring 20 and the outer retainer ring 30. More specifically, the inner edge of the barrier seal 120 is connected to the lower end of the inner drive ring 22, and the outer edge of the barrier seal 120 is connected to the lower end of the outer drive ring 32. The barrier seal 120 has an inverted U-shaped cross section bent upward, and is formed of a material that is easily deformed. For example, the barrier seal 120 can be formed of a rubber material having excellent strength and durability, such as ethylene propylene rubber (EPDM), polyurethane rubber, and silicon rubber.

  The barrier seal 120 is disposed above the inner ring member 21 and the outer ring member 31 and below the stopper 119. The inner ring member 21 and the outer ring member 31 are always kept in non-contact, and the inner retainer ring 20 and the outer retainer ring 30 do not contact below the barrier seal 120. Accordingly, no abrasion powder is generated below the barrier seal 120. The barrier seal 120 allows a relative movement between the inner retainer ring 20 and the outer retainer ring 30 while preventing a foreign matter generated inside the top ring body 10 from dropping on the polishing surface 2a, and the inner retainer ring 20. It is possible to prevent the polishing liquid (slurry) from entering the top ring body 10 from the gap between the outer retainer ring 30 and the outer retainer ring 30.

  A seal sheet 123 that connects the top ring main body 10 and the outer retainer ring 30 is provided on the outer periphery of the top ring 1. The seal sheet 123 is an annular elastic film, and is disposed over the entire circumference of the top ring body 10 and the outer retainer ring 30 so as to close a gap between the top ring body 10 and the outer retainer ring 30. More specifically, the upper end of the seal sheet 123 is connected to the lower end of the outer peripheral surface of the top ring body 10, and the lower end of the seal sheet 123 is connected to the outer peripheral surface of the outer retainer ring 30. The seal sheet 123 has a bellows shape so as to be easily deformed in the vertical direction. Similar to the barrier seal 120, the seal sheet 123 is formed of a rubber material having excellent strength and durability, such as ethylene propylene rubber (EPDM), polyurethane rubber, and silicon rubber.

  The seal sheet 123 allows the outer retainer ring 30 to move up and down relative to the top ring body 10 while preventing foreign matter generated inside the top ring body 10 from falling on the polishing surface 2a. It is possible to prevent the polishing liquid (slurry) from entering the top ring body 10 from the gap with the outer retainer ring 30.

  Normally, after the wafer is polished, the inner retainer ring 20 and the outer retainer ring 30 are cleaned with a cleaning solution such as ultrapure water or a chemical solution. Therefore, in order to efficiently introduce the cleaning liquid into the gap between the inner retainer ring 20 and the outer retainer ring 30, a plurality of vertical grooves are formed on the outer peripheral surface of the inner retainer ring 20 and / or the inner peripheral surface of the outer retainer ring 30. It is preferable to do.

  Fig.11 (a) is the figure which looked at the inner retainer ring 20 and the outer retainer ring 30 from the bottom, and FIG.11 (b) is the XI-XI sectional view taken on the line shown to Fig.11 (a). A plurality of vertical grooves 20 a are formed on the inner peripheral surface of the inner ring member 21, and a plurality of vertical grooves 20 b are formed on the outer peripheral surface of the inner ring member 21. Further, a radial groove 20 c extending in the radial direction is formed on the lower surface of the inner ring member 21. The vertical grooves 20a and 20b extend upward from the lower surface of the inner retainer ring 20 (that is, the lower surface of the inner ring member 21), and extend higher than the radial groove 20c. The vertical grooves 20 a and 20 b and the radial groove 20 c are provided at equal intervals in the circumferential direction of the inner retainer ring 20. The radial groove 20 c penetrates the inner retainer ring 20 in the radial direction, but the longitudinal grooves 20 a and 20 b do not penetrate the inner retainer ring 20. The vertical grooves 20a and 20b are disposed at the same position as the radial groove 20c in the circumferential direction of the inner retainer ring 20, and the vertical grooves 20a and 20b communicate with the radial groove 20c. The vertical grooves 20a and 20b have the same width as the radial groove 20c, but may be narrower or wider than the radial groove 20c.

  Similarly, a plurality of vertical grooves 30 a are formed on the inner peripheral surface of the outer ring member 31, and radial grooves 30 b extending in the radial direction are formed on the lower surface of the outer ring member 31. The vertical groove 30a extends upward from the lower surface of the outer retainer ring 30 (that is, the lower surface of the outer ring member 31), and extends upward higher than the radial groove 30b. The longitudinal grooves 30 a and the radial grooves 30 b are provided at equal intervals in the circumferential direction of the outer retainer ring 30. The radial groove 30 b penetrates the outer retainer ring 30 in the radial direction, but the vertical groove 30 a does not penetrate the outer retainer ring 30. The vertical groove 30a is disposed at the same position as the radial groove 30b in the circumferential direction of the outer retainer ring 30, and the vertical groove 30a communicates with the radial groove 30b. The vertical groove 30a has the same width as the radial groove 30b, but may be narrower or wider than the radial groove 30a. The vertical grooves 20 a and 20 b and the vertical groove 30 a are located below the barrier seal 120.

  The cleaning liquid supplied to the lower surfaces of the inner retainer ring 20 and the outer retainer ring 30 is introduced into the gap between the inner retainer ring 20 and the outer retainer ring 30 through the vertical groove 20b and the vertical groove 30a, and polishing existing in this gap. Wash off the liquid. Further, the cleaning liquid is introduced into the gap between the inner retainer ring 20 and the elastic film 45 through the vertical groove 20a, and the polishing liquid existing in the gap is washed away. Therefore, the inner retainer ring 20 and the outer retainer ring 30 can maintain their smooth movement.

  During polishing of the wafer, a polishing liquid is supplied onto the polishing surface 2a of the polishing pad 2. Therefore, the wafer is polished by sliding contact with the polishing surface 2 a of the polishing pad 2 in a state where the polishing liquid is present between the wafer and the polishing pad 2. Inner retainer ring for facilitating the inflow of the polishing liquid between the wafer and the polishing pad 2 or for facilitating the outflow of the polishing liquid having finished the polishing action between the wafer and the polishing pad 2 A plurality of radial grooves 20 c and 30 b are provided on the lower surfaces of the outer retainer ring 30 and the outer ring 20, respectively. The cross-sectional shape and the number of the radial grooves 20c and 30b are appropriately selected according to the purpose of providing the radial grooves.

  12A to 12C are views showing examples of radial grooves 20c and 30b provided on the lower surfaces of the inner retainer ring 20 and the outer retainer ring 30, respectively. In this example, the radial grooves 20 c and 30 b extend in the radial direction of the inner retainer ring 20 and the outer retainer ring 30. FIG. 12A shows an example in which the number of radial grooves 30b is the same as the number of radial grooves 20c, and FIG. 12B shows an example in which the number of radial grooves 30b is less than the number of radial grooves 20c. 12 (c) shows an example in which the number of radial grooves 20c is smaller than the number of radial grooves 30b. In order to effectively inflow and outflow of the polishing liquid, it is preferable that the circumferential positions of the radial grooves 20c and 30b coincide with each other.

  FIGS. 13A to 13C are diagrams showing other examples of the radial grooves 20c and 30b provided on the lower surfaces of the inner retainer ring 20 and the outer retainer ring 30, respectively. 13A shows an example in which the number of radial grooves 30b is the same as the number of radial grooves 20c, and FIG. 13B shows an example in which the number of radial grooves 30b is smaller than the number of radial grooves 20c. 13 (c) shows an example in which the number of radial grooves 20c is smaller than the number of radial grooves 30b. In this example, the radial grooves 20 c and 30 b are inclined with respect to the radial direction of the inner retainer ring 20 and the outer retainer ring 30. More specifically, the radial grooves 20c and 30b are formed in the inner retainer so that the polishing liquid flows from the outside to the inside of the outer retainer ring 30 and the inner retainer ring 20 as the inner retainer ring 20 and the outer retainer ring 30 rotate. The ring 20 and the outer retainer ring 30 are inclined forward with respect to the rotational direction (indicated by arrows).

  14 (a) to 14 (c) are diagrams showing still other examples of the radial grooves 20c and 30b provided on the lower surfaces of the inner retainer ring 20 and the outer retainer ring 30, respectively. 14A shows an example in which the number of radial grooves 30b is the same as the number of radial grooves 20c, and FIG. 14B shows an example in which the number of radial grooves 30b is smaller than the number of radial grooves 20c. 14 (c) shows an example in which the number of radial grooves 20c is smaller than the number of radial grooves 30b. Also in this example, the radial grooves 20c and 30b are inclined with respect to the radial direction of the inner retainer ring 20 and the outer retainer ring 30, but the inclination direction is opposite to the example shown in FIG. Yes. That is, the radial grooves 20c and 30b are formed in the inner retainer ring 20 and the outer retainer ring 20 so that the polishing liquid flows out from the inside to the outside of the outer retainer ring 30 and the inner retainer ring 20 as the inner retainer ring 20 and the outer retainer ring 30 rotate. The retainer ring 30 is inclined backward with respect to the rotation direction (indicated by an arrow).

  The inner retainer ring 20 and the outer retainer ring 30 may have different or the same cross-sectional shapes, widths, and numbers of the radial grooves 20c and 30b. The depth of the radial grooves 20c and 30b is selected so as to contribute to the inflow and out of the polishing liquid even when the inner retainer ring 20 and the outer retainer ring 30 are worn.

  12 to 14 show an example of the outer retainer ring 30 having the radial groove 30b. However, when it is desired to suppress the inflow and outflow of the polishing liquid, the outer retainer ring 30 having no radial groove may be used. preferable. When the outer retainer ring 30 is not provided with a radial groove, it is preferable to provide a plurality of through holes 35 extending from the inner peripheral surface of the outer retainer ring 30 to the outer peripheral surface as shown in FIG. These through holes 35 penetrate the outer retainer ring 30 in the radial direction, and are formed over the entire circumference of the outer retainer 30. These through holes 30 enable the inner retainer ring 20 and the outer retainer ring 30 to move smoothly up and down. The through hole 35 is preferably arranged below the barrier seal 120 and the seal sheet 123. This is to prevent the polishing liquid from entering the area surrounded by the barrier seal 120 and the seal sheet 123 and to prevent foreign matter from falling onto the polishing surface 2a from the enclosed area. is there.

  The outer retainer ring 30 can uniformly press the polishing surface 2a of the polishing pad 2 during wafer polishing. An effect of providing such an outer retainer ring 30 is an improvement in the controllability of the polishing profile of the edge portion of the wafer. Here, the edge portion of the wafer is a region having a width of about 3 mm located at the outermost peripheral edge of the wafer. During polishing of the wafer, the polishing profile of the edge portion of the wafer can be controlled by pressing the polishing pad 2 with the outer retainer ring 30 outside the inner retainer ring 20. In order to control the effect of such a polishing pad rebound by the outer retainer ring 30, the distance between the inner retainer ring 20 and the outer retainer ring 30 may be changed. The distance between the inner retainer ring 20 and the outer retainer ring 30 (more specifically, the distance between the lower surface of the inner retainer ring 20 and the lower surface of the outer retainer ring 30) is preferably 0.1 mm to 3 mm.

  As shown in FIG. 3, a plurality of reinforcing pins (reinforcing members) 125 are embedded in the inner retainer ring 20. These reinforcing pins 125 are arranged at equal intervals in the circumferential direction of the inner retainer ring 20. Each reinforcing pin 125 extends vertically and is fixed to the inner drive ring 22 by a bolt 126. The lower end of the reinforcing pin 125 is located in the vicinity of the lower end of the inner ring member 21, and the upper end of the reinforcing pin 125 is located in the inner drive ring 22. Examples of the material of the reinforcing pin 125 include metal materials such as stainless steel or ceramics. The reinforcing pin 125 embedded in the inner retainer ring 20 can improve the rigidity of the inner retainer ring 20. Therefore, the deformation of the inner retainer ring 20 when receiving a lateral force from the wafer during polishing of the wafer can be reduced, and as a result, the inner retainer ring 20 presses the polishing pad 2 more uniformly. Can do.

  Advantages of removably fixing the reinforcing pin 125 to the inner drive ring 22 with the bolt 126 include the following. In order to improve the rigidity of the inner retainer ring 20, it is desirable to make the difference between the outer diameter of the reinforcing pin 125 and the diameter of the hole of the inner ring member 21 into which the reinforcing pin 125 fits as small as possible. Furthermore, the alignment of the plurality of reinforcing pins 125 and the holes of the inner ring member 21 is very important. When the inner ring member 21 is attached in a state where the positions of the reinforcing pins 125 and the holes of the inner ring member 21 are slightly shifted, the inner ring member 21 is distorted, and the uniform pressing of the polishing pad 2 is prevented. It becomes. Therefore, when the inner ring member 21 is attached to the inner drive ring 22, the following procedure is performed. First, the bolt 126 for fixing the reinforcing pin 125 is temporarily fixed, and the reinforcing pin 125 is allowed to move slightly in the horizontal direction. Next, the reinforcing pin 125 is fitted into the hole of the inner ring member 21. By doing so, misalignment between the reinforcing pin 125 and the hole of the inner ring member 21 can be absorbed. Thereafter, the bolt 126 is tightened to fix the reinforcing pin 125, and finally the inner ring member 21 is fixed to the inner drive ring 22 with the bolt 24 as shown in FIG.

  Hereinafter, the detailed configuration of the top ring 1 will be further described. As shown in FIG. 3, the edge holder 50 is held by a ripple holder 51. The ripple holder 51 is attached to the lower portion of the carrier 43 by a plurality of stoppers 54. As shown in FIGS. 4 and 6, the ripple holder 52 is attached to the lower portion of the carrier 43 by a plurality of stoppers 55. The stopper 54 and the stopper 55 are provided at equal intervals in the circumferential direction of the top ring 1.

  As shown in FIG. 3, a center chamber 130 is formed in the central portion of the elastic film 45. The ripple holder 52 is formed with a channel 140 communicating with the center chamber 130, and the carrier 43 is formed with a channel 141 communicating with the channel 140. The flow path 141 is connected to a fluid supply source (not shown), and pressurized fluid (for example, pressurized air) is supplied to the center chamber 130 through the flow path 141 and the flow path 140. ing.

  The ripple holder 51 is configured to press the ripple 45b of the elastic film 45 against the lower part of the carrier 43 with the claw part 51a, and the ripple holder 52 is configured to press the ripple 45a of the elastic film 45 against the lower part of the carrier 43 with the claw part 52a. It has become. The edge 45c of the elastic film 45 is pressed against the edge holder 50 by the claw portion 51b.

  As shown in FIG. 2, an annular ripple chamber 131 is formed between the ripple 45 a and the ripple 45 b of the elastic film 45. A gap 45 f is formed between the ripple holder 51 and the ripple holder 52 of the elastic film 45, and a flow path 142 communicating with the gap 45 f and the ripple chamber 131 is formed in the carrier 43. The flow path 142 is connected to a fluid supply source (not shown), and pressurized fluid is supplied to the ripple chamber 131 through the flow path 142. The flow path 142 is also connected to a vacuum pump (not shown) so as to be switchable. The wafer can be attracted to the lower surface of the elastic film 45 by the operation of the vacuum pump.

  The ripple holder 51 is formed with a flow path (not shown) communicating with the annular outer chamber 132 formed by the ripple 45 b and the edge 45 c of the elastic film 45. The flow path of the ripple holder 51 is connected to a fluid supply source (not shown) so that pressurized fluid is supplied to the outer chamber 132.

  As shown in FIGS. 4 and 8, the edge holder 50 is configured to hold the edge 45 d of the elastic film 45 and hold it under the carrier 43. In the edge holder 50, a flow path 143 communicating with an annular edge chamber 133 formed by the edges 45c and 45d of the elastic film 45 is formed. The flow path 143 of the edge holder 50 is connected to a fluid supply source (not shown) so that pressurized fluid is supplied to the edge chamber 133.

  As described above, in the top ring 1 according to the present embodiment, the pressure chamber formed between the elastic film 45 and the carrier 43 of the top ring body 10, that is, the center chamber 130, the ripple chamber 131, the outer chamber 132, and By adjusting the pressure of the fluid supplied to the edge chamber 133, the pressing force for pressing the wafer against the polishing pad 2 can be adjusted for each portion of the wafer.

  A rolling diaphragm 62 (see FIG. 8) used for the inner pressing mechanism 60 is made of an elastic film having a bent portion. The bent portion rolls due to a change in the internal pressure of the chamber 69 partitioned by the rolling diaphragm 62. By moving, the space of the chamber 69 can be expanded. When the chamber 69 expands, the rolling diaphragm 62 does not slide with the inner cylinder 63 and hardly expands or contracts, so that sliding friction is extremely small. Therefore, there is an advantage that the rolling diaphragm 62 can have a long life, and the pressing force applied to the polishing pad 2 by the inner retainer ring 20 can be adjusted with high accuracy. Further, even if the inner ring member 21 of the inner retainer ring 20 is worn, the pressing force of the inner retainer ring 20 can be kept constant. The rolling diaphragm 82 used for the outer pressing mechanism 80 has the same configuration as the rolling diaphragm 62 of the inner pressing mechanism 60, and has the same advantages.

  As shown in FIG. 6, the connecting member 100 that connects the inner drive ring 22 and the spherical bearing 111 has eight spokes 102 that extend radially. These spokes 102 are respectively housed in eight concave grooves 43 g formed radially on the upper surface of the carrier 43. The carrier 43 is provided with a plurality of pairs of inner ring driving collars 150, 150, and each pair of inner ring driving collars 150, 150 is disposed on both sides of each spoke 102. In the example shown in FIG. 6, four pairs of inner ring driving collars 150 and 150 are provided, and four pairs of inner ring driving collars 150 and 150 are arranged on four of the eight spokes 102, respectively. .

  The top ring body 10 is connected to the top ring shaft 7, and the top ring body 10 is rotated by the top ring shaft 7. The rotation of the top ring body 10 is transmitted from the carrier 43 to the spoke 102 via a plurality of pairs of inner ring driving collars 150 and 150, and the top ring body 10 and the inner retainer ring 20 rotate together. The inner ring driving collar 150 is made of a low friction material such as PTFE, PEEK, or PPS. Both side surfaces of the spoke 102 with which the inner ring driving collar 150 contacts are mirror-finished to improve the surface roughness of both side surfaces of the spoke 102. The inner ring driving collar 150 may be mirror-finished, and a low friction material may be provided on both sides of the spoke 102 by coating or the like.

  With such a configuration, the slidability between the inner ring driving collar 150 and the spoke 102 can be improved. Therefore, the inner retainer ring 20 can be tilted smoothly and a desired pressing force can be uniformly applied to the polishing surface 2a. In addition, since a rotation drive unit (inner ring drive collar 150 and spoke 102) that transmits rotation from the top ring body 10 to the inner retainer ring 20 is provided in the top ring body 10, wear powder generated in the rotation drive unit is removed from the top ring. It can be contained in the main body 10. Therefore, the wear powder does not fall to the polishing surface 2a, and the wafer defects such as scratches caused by the wear powder can be drastically reduced.

  As shown in FIG. 7, a plurality of recesses 20d are formed on the outer peripheral surface of the inner retainer ring 20, and outer ring drive pins 152 provided on the outer retainer ring 30 are disposed in the plurality of recesses 20d. Yes. A cylindrical outer ring driving collar 153 is attached to the outer peripheral surface of the outer ring driving pin 152. In FIG. 7, a horizontal section of the outer ring drive collar 153 is shown. The outer ring drive collar 153 is made of a low friction material such as PTFE, PEEK, PPS. Each recess 20d has both side surfaces extending in the vertical direction, and the outer ring driving collar 153 comes into contact with one side surface of the recess 20d when the inner retainer ring 20 rotates. The rotation of the inner retainer ring 20 is transmitted to the outer retainer ring 30 via the outer ring drive pin 152, and the inner retainer ring 20 and the outer retainer ring 30 rotate together. Both side surfaces of the recess 20d are mirror-finished to improve the surface roughness of the recess 20d with which the outer ring driving collar 153 made of a low friction material contacts.

  With such a configuration, the slidability between the outer ring drive collar 153 and the recess 20d can be improved. Therefore, the inner retainer ring 20 can be tilted smoothly and a desired pressing force can be uniformly applied to the polishing surface 2a. Further, the outer retainer ring 30 can uniformly apply a desired pressing force to the polishing surface 2a without being affected by the tilt of the inner retainer ring 20. In this embodiment, the recess 20d is disposed in the inner retainer ring 20, and the outer ring drive pin 152 is disposed in the outer retainer ring 30. Conversely, the outer ring drive pin is disposed in the inner retainer ring 20, and the recess is disposed in the outer retainer ring 30. It is also possible to provide it. A rubber cushion may be provided between the outer ring drive pin 152 and the outer ring drive collar 153.

  As shown in FIGS. 4 and 7, a plurality of stopper pins 155 protruding inward in the radial direction are fixed to the inner retainer ring 20. These stopper pins 155 are gently engaged with a plurality of recesses 43 h formed in the carrier 43 of the top ring body 10 and extending in the longitudinal direction. These recesses 43 h are formed at equal intervals on the outer peripheral surface of the carrier 43. The stopper pin 155 is movable in the vertical direction between the upper end and the lower end of the recess 43h. In other words, the vertical movement of the inner retainer ring 20 with respect to the top ring body 10 is limited by the stopper pin 155 and the recess 43h. That is, when the stopper pin 155 contacts the upper end of the recess 43h, the inner retainer ring 20 is in the uppermost position with respect to the top ring body 10, and when the stopper pin 155 contacts the lower end of the recess 43h of the carrier 43, the inner retainer ring 20 The retainer ring 20 is in the lowest position with respect to the top ring body 10. With such a configuration, the inner retainer ring 20 is prevented from dropping from the top ring body 10.

  As shown in FIG. 4, the outer ring driving collar 153 is movable in the vertical direction between the upper end and the lower end of the recess 20 d formed in the inner retainer ring 20. In other words, the vertical movement of the outer retainer ring 30 relative to the inner retainer ring 20 is limited by the outer ring drive collar 153 and the recess 20d. That is, when the outer ring drive collar 153 contacts the upper end of the recess 20d, the outer retainer ring 30 is in the uppermost position with respect to the inner retainer ring 20, and when the outer ring drive collar 153 contacts the lower end of the recess 20d, The outer retainer ring 30 is at the lowest position with respect to the inner retainer ring 20. With such a configuration, the outer retainer ring 30 is prevented from dropping from the inner retainer ring 20, that is, the top ring body 10.

  As described above, the inner piston 61 and the inner retainer ring 20 are fixed by magnetic force. With such a configuration, even when the inner retainer ring 20 receives vibration during polishing, the inner piston 61 and the inner retainer ring 20 are not separated from each other, and sudden rise of the inner retainer ring 20 due to vibration is prevented. Can do. Therefore, the pressing force of the inner retainer ring 20 can be stabilized, and the possibility that the wafer will come off (slip out) from the top ring 1 can be reduced. Furthermore, the inner retainer ring 20 that requires frequent maintenance can be easily separated from the inner piston 61 that requires less maintenance. Since the outer piston 81 and the outer retainer ring 30 are similarly fixed by magnetic force, the same advantage can be obtained.

  When the maintenance bolt 16 is removed as shown in FIG. 4, the carrier 43 holding the elastic film 45 together with the inner retainer ring 20 and the outer retainer ring 30 is separated from the spacer 42. Thus, since the inner retainer ring 20, the outer retainer ring 30, and the carrier 43 can be separated from the top ring 1, the maintenance of the inner retainer ring 20 and the outer retainer ring 30 and the maintenance of the elastic film 45 are easily performed. be able to. As shown in FIG. 6, notches 22 a and 32 a are provided on the upper surface of the inner drive ring 22 and the upper surface of the outer drive ring 32, respectively. During maintenance of the outer retainer ring 30, for example, a thin plate-like member is inserted into the notch 32 a from the outer peripheral side, thereby reducing the magnetic force between the outer retainer ring 30 and the outer piston 81 and easily separating them. can do. The inner retainer ring 20 and the inner piston 61 can be similarly separated by inserting a plate-like member into the notch 22a.

  As shown in FIG. 8, the edge (outer peripheral edge) 45 d of the elastic film 45 is formed with a seal member 158 that is bent upward and connects the elastic film 45 and the inner retainer ring 20. The seal member 158 is disposed so as to close the gap between the top ring body 10 and the inner drive ring 22 and is formed of a material that is easily deformed. The seal member 158 prevents the foreign matter from falling from the top ring 1 to the polishing surface 2a while allowing the relative movement between the top ring body 10 and the inner retainer ring 20, and further, the top ring body 10 and the inner retainer ring 20 It is possible to prevent the polishing liquid from entering the top ring 1 through the gap. In the present embodiment, the seal member 158 is formed integrally with the edge 45d of the elastic film 45 and has an inverted U-shaped cross-sectional shape.

  When the seal sheet 123, the seal member 158, and the barrier seal 120 are not provided, the polishing liquid enters the top ring 1, and the top ring body 10, the inner retainer ring 20, and the outer retainer constituting the top ring 1. The normal operation of the ring 30 will be hindered. According to this embodiment, the sealing sheet 123, the sealing member 158, and the barrier seal 120 can prevent the polishing liquid from entering the top ring 1, and thus the top ring 1 can be operated normally. . The elastic film 45, the seal sheet 123, the seal member 158, and the barrier seal 120 are formed of a rubber material having excellent strength and durability, such as ethylene propylene rubber (EPDM), polyurethane rubber, and silicone rubber.

  In the top ring 1 of the present embodiment, the pressure applied to the wafer is controlled by the pressure supplied to the center chamber 130, the ripple chamber 131, the outer chamber 132, and the edge chamber 133 of the elastic film 45. Needs to be positioned away from the polishing pad 2 upward. Since the inner retainer ring 20 and the outer retainer ring 30 can move up and down independently of the top ring main body 10, even if the inner retainer ring 20 and the outer retainer ring 30 are worn, the wafer and the top ring being polished are removed. The distance between the main body 10 can be kept constant. Therefore, the polishing profile of the wafer can be stabilized.

  In the above-described example, the elastic film 45 is disposed on substantially the entire surface of the wafer. However, the present invention is not limited to this, and the elastic film 45 only needs to be in contact with at least a part of the wafer. In the example described above, the elastic film 45 includes the four chambers of the center chamber 130, the ripple chamber 131, the outer chamber 132, and the edge chamber 133, but the present invention is not limited thereto. Fewer than four chambers may be arranged, and more than four chambers may be arranged. In particular, by arranging more than four chambers, it is possible to control a polishing profile in a narrower range in the radial direction of the wafer.

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

DESCRIPTION OF SYMBOLS 1 Top ring 2 Polishing pad 2a Polishing surface 3 Polishing table 5 Polishing liquid supply mechanism 7 Top ring shaft 8 Top ring head 10 Top ring main body 16 Maintenance bolt 20 Inner retainer ring 21 Inner ring member 22 Inner drive ring 30 Outer retainer ring 31 Outer Ring member 32 Outer drive ring 41 Flange 42 Spacer 43 Carrier 45 Elastic film 50 Edge holder 51, 52 Lip holder 54, 55 Stopper 60 Inner pressing mechanism 61 Inner piston 62 Inner rolling diaphragm 63 Inner cylinder 64 Holding member 65 Bolt 68 Magnet 69 Inner Pressure chamber 70 Channel 80 Outer pressing mechanism 81 Outer piston 82 Outer rolling diaphragm 83 Outer casing Sander 84 Holding member 85 Bolt 88 Magnet 89 Outer pressure chamber 90 Flow path 100 Connecting member 101 Shaft part 102 Spoke 111 Spherical bearing 113 Outer ring 114 Intermediate ring 115 Inner ring 119 Stopper 120 Barrier seal 123 Seal sheet 125 Reinforcement pin 130 Center chamber 131 Ripple chamber 132 Outer chamber 133 Edge chamber 140, 141, 142, 143 Flow path 150 Inner ring drive collar 152 Outer ring drive pin 153 Outer ring drive collar 155 Stopper pin 158 Seal member

Claims (23)

A top ring body that holds an elastic film for pressing the substrate against the polishing surface;
An inner retainer ring that can move up and down independently of the top ring body and is arranged to surround the substrate;
An inner pressing mechanism for pressing the inner retainer ring against the polishing surface;
An outer retainer ring that is provided on the radially outer side of the inner retainer ring and is movable up and down independently of the inner retainer ring and the top ring body;
An outer pressing mechanism for pressing the outer retainer ring against the polishing surface;
A support mechanism that receives a lateral force applied to the inner retainer ring from the substrate during polishing of the substrate and does not allow transmission of the lateral force from the inner retainer ring to the outer retainer ring. A substrate holding device.   The substrate holding apparatus according to claim 1, wherein the support mechanism is disposed in the top ring body.   The substrate holding apparatus according to claim 1, wherein the inner pressing mechanism and the outer pressing mechanism are capable of independently pressing the inner retainer ring and the outer retainer ring against the polishing surface.   4. The substrate holding apparatus according to claim 1, wherein the inner retainer ring is supported by the support mechanism so as to be tiltable. 5.   The substrate holding apparatus according to claim 4, wherein a center of tilting of the inner retainer ring is located below the support mechanism.   The substrate holding apparatus according to claim 5, wherein the center of tilting of the inner retainer ring is on the polishing surface or in the vicinity of the polishing surface.   The substrate holding apparatus according to claim 1, wherein the inner retainer ring is supported by the support mechanism so as to be movable up and down. A top ring body that holds an elastic film for pressing the substrate against the polishing surface;
A retainer ring disposed to surround the substrate and in contact with the polishing surface;
A spherical bearing for tiltably supporting the retainer ring;
The center of the retainer ring is tilted below the spherical bearing. A pressing mechanism for pressing the retainer ring against the polishing surface;
The substrate holding apparatus according to claim 8, wherein the retainer ring is configured to be movable up and down independently of the top ring main body.   The substrate holding apparatus according to claim 9, wherein the retainer ring is supported by the spherical bearing so as to be movable up and down. The spherical bearing is connected to the retainer ring, and has an intermediate ring having a partial spherical shell shape, an outer ring that supports the intermediate ring in a slidable manner from above, and a slidable support from the bottom. With an inner ring,
11. The substrate holding apparatus according to claim 8, wherein sliding surfaces of the outer ring, the intermediate ring, and the inner ring have a partial spherical shape that is smaller than an upper half of a spherical surface.   The substrate holding device according to claim 11, wherein at least one of the sliding surfaces of the outer ring, the intermediate ring, and the inner ring is formed of ceramic.   The substrate holding apparatus according to claim 8, wherein the center of tilting of the retainer ring is on the polishing surface or in the vicinity of the polishing surface. The retainer ring is an inner retainer ring;
The substrate holding apparatus according to claim 8, further comprising an outer retainer ring that is provided on an outer side in the radial direction of the inner retainer ring and contacts the polishing surface. An outer pressing mechanism for pressing the outer retainer ring against the polishing surface;
15. The substrate holding apparatus according to claim 14, wherein the outer retainer ring is configured to move up and down independently of the inner retainer ring and the top ring main body. A top ring body that holds an elastic film for pressing the substrate against the polishing surface;
An inner retainer ring arranged to surround the substrate and in contact with the polishing surface;
An outer retainer ring provided on the radially outer side of the inner retainer ring and in contact with the polishing surface;
A substrate holding apparatus comprising: a barrier seal that closes a gap between the inner retainer ring and the outer retainer ring. An inner pressing mechanism for pressing the inner retainer ring against the polishing surface;
The substrate holding apparatus according to claim 16, wherein the inner retainer ring is configured to be movable up and down independently of the top ring main body. An outer pressing mechanism for pressing the outer retainer ring against the polishing surface;
18. The substrate holding apparatus according to claim 16, wherein the outer retainer ring is configured to be vertically movable independently of the inner retainer ring and the top ring main body.   The substrate holding device according to claim 16, wherein the inner retainer ring and the outer retainer ring do not contact each other below the barrier seal.   A support mechanism that receives a lateral force applied from the substrate to the inner retainer ring during polishing of the substrate and does not allow transmission of the lateral force from the inner retainer ring to the outer retainer ring is further provided. The substrate holding device according to claim 16, wherein   21. The substrate holding apparatus according to claim 20, wherein the support mechanism is disposed in the top ring body. A substrate holding device according to any one of claims 1 to 21,
A polishing apparatus comprising: a polishing table that supports a polishing pad having a polishing surface. Rotate the polishing table that supports the polishing pad,
Supplying a polishing liquid onto the polishing surface of the polishing pad;
A polishing method comprising polishing the substrate by pressing the substrate against the polishing surface with the substrate holding device according to any one of claims 1 to 21.

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