Source: http://www.google.com/patents/US20020173256?dq=7,003,515
Timestamp: 2014-04-23 09:56:13
Document Index: 503834338

Matched Legal Cases: ['art 18', 'art 18', 'art 18', 'art 18', 'art 18', 'art 44', 'art 18', 'art 18', 'art 18', 'art 18', 'art 18', 'art 18', 'art 18', 'art 18', 'art 18', 'art 18', 'art 18', 'art 18', 'art 18', 'art 18', 'art 18', 'art 44']

Patent US20020173256 - Polishing machine - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign inAdvanced Patent SearchPatentsIn the polishing machine, bad influence caused by a surface condition of a retainer ring can be reduced with a simple structure. The polishing machine comprises: a rotatable polishing plate; a top ring including a holding plate for holding and pressing a wafer onto polishing cloth of the polishing plate;...http://www.google.com/patents/US20020173256?utm_source=gb-gplus-sharePatent US20020173256 - Polishing machineAdvanced Patent SearchPublication numberUS20020173256 A1Publication typeApplicationApplication numberUS 10/136,872Publication dateNov 21, 2002Filing dateMay 1, 2002Priority dateMay 2, 2001Also published asDE60221163D1, DE60221163T2, EP1254743A2, EP1254743A3, EP1611996A1, EP1611996B1, US6916234Publication number10136872, 136872, US 2002/0173256 A1, US 2002/173256 A1, US 20020173256 A1, US 20020173256A1, US 2002173256 A1, US 2002173256A1, US-A1-20020173256, US-A1-2002173256, US2002/0173256A1, US2002/173256A1, US20020173256 A1, US20020173256A1, US2002173256 A1, US2002173256A1InventorsHitoshi SuwabeOriginal AssigneeHitoshi SuwabeExport CitationBiBTeX, EndNote, RefManReferenced by (3), Classifications (9), Legal Events (4) External Links: USPTO, USPTO Assignment, EspacenetPolishing machineUS 20020173256 A1Abstract In the polishing machine, bad influence caused by a surface condition of a retainer ring can be reduced with a simple structure. The polishing machine comprises: a rotatable polishing plate; a top ring including a holding plate for holding and pressing a wafer onto polishing cloth of the polishing plate; a retainer ring in which the holding plate is freely inserted, the retainer ring independently rotating, the retainer ring including a pressing member, which presses the polishing cloth along an outer edge of the wafer so as to make level of the polishing cloth pressed by the pressing member substantially equal to that of the polishing cloth pressed by the wafer; and a positioning member for correctly positioning the retainer ring on the polishing cloth while the retainer ring is rotated. Images(11) Claims(15)
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0060] Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings. [0061] In a polishing machine of a first embodiment of the present invention, a lower surface of a wafer, which has been held on a holding face of a holding plate of a top ring, is pressed onto and polished by polishing cloth of a polishing plate rotating. A head section having the top ring, etc. is shown in FIG. 1. FIG. 1 is a sectional view of the head section. The top ring 10 is provided to a lower end of a rotary shaft 12, which is vertically moved by proper elevating means (not shown), e.g., a cylinder unit, and rotated by proper rotating means (not shown), e.g., a motor. The top ring 10 includes: a main body section 14 fixed to the lower end of the rotary shaft 12; and a holding plate 22 provided in a concave part 18, which is formed in the main body section 14 and whose opening faces polishing cloth 16 adhered on an upper face of a polishing plate. The holding plate 22 is elastically suspended, by a donut-shaped elastic sheet 20, in the concave part 18, so that the holding plate 22 can be moved in the vertical direction. [0062] In the main body section 14, a space 24 is formed between inner faces of the concave part 18 and the holding plate 22. Compressed air is supplied into and discharged from the space 24 by proper pressure means (not shown) via a pipe 26 provided in the rotary shaft 12. When air pressure in the space 24 exceeds elasticity of the elastic sheet 20, the holding plate 22 downwardly projected from the concave part 18. On the other hand, if the air pressure in the space 24 is smaller than the elasticity of the elastic sheet 20, the holding plate 22 is retracted in the concave part 18 by the elasticity. [0063] Further, a plurality of through-holes 28 are formed in the holding plate 22, and their lower ends are opened in a holding face (a bottom face) of the holding plate 22. The through-holes 28 are mutually communicated by a communicating space 30. The communicating space 30 is communicated to proper vacuum means (not shown), e.g., a vacuum pump, via a pipe 32 provided in the rotary shaft 12, an air path 34 formed in the main body section 14 and a flexible pipe 35 provided in the space 24. With this structure, a wafer �W� can be sucked and held on the holding face of the holding plate 22 by actuating the vacuum means. When the vacuum means is stopped, negative pressure in the communicating space 30 is disappeared, so that the wafer �W� can be released from the holding face of the holding plate 22. [0064] Note that, the wafer �W� may be held on the holding plate 22 by the negative pressure and surface tension of water absorbed in a bucking member, e.g., unwoven cloth, adhered on the holding face of the holding plate 22. Namely, the holding plate 22 may directly or indirectly hold the wafer �W� on the holding face. In the case of using the water surface tension, the wafer �W� may be held on the holding plate 22 by the water surface tension only while the wafer �W� is polished. [0065] The top ring 10 is freely inserted in a retainer ring 40. The retainer ring 40 has a ring-shaped pressing member 42, which encloses the holding plate 22. A projected part 44, whose bottom face acts as a pressing face for pressing the polishing cloth 16, is downwardly projected along an inner edge of the pressing member 42. [0066] Pins 46 are upwardly extended from the pressing member 42, and ring-shaped weights 48 are piled and correctly positioned by fitting with the pins 46. The weights 48 apply pressing force to the pressing member 42, so that the pressing face is capable of pressing the polishing cloth 16 with proper pressing force. The pressing force is defined on the basis of pressing force for pressing the wafer �W� onto the polishing cloth 16. [0067] In the case of positioning the retainer ring 40 on the polishing face 16 by rollers 50 (see FIG. 3), preferably outer circumferential faces of the weights 48 are located on the inner side with respect to an outer circumferential face of the pressing member 42 so as to make the rollers 50 contact the outer circumferential face of the pressing member 42 without contacting the outer circumferential faces of the weights 48. [0068] In FIG. 1, the top ring 10, which is provided to the lower end of the rotary shaft 12, and the retainer ring 40, which is separated from the rotary shaft 12, are not integrated. Therefore, as shown in FIG. 2, the top ring 10 can be freely inserted into and pulled out from the retainer ring 40 mounted on the polishing cloth 16 adhered on the polishing plate. [0069] The retainer ring 40 is correctly positioned, so that the top ring 10 can be inserted into and pulled out without contacting the retainer ring 40. [0070] The rollers 50 are capable of correctly positioning the retainer ring 40 on the polishing cloth 16 of the polishing plate 15 as shown in FIG. 3. The rollers 50 are attached to an arm 54, which is extended from a rotary shaft 52. The rotary shaft 52 is rotatably attached to a base section of the polishing machine and located outside of the polishing plate 15. The rollers 50 contact the retainer ring 40, which is moved with the rotation �A� of the polishing plate 15, at two points, so that the retainer ring 40 can be correctly positioned at a prescribed position. [0071] As shown in FIG. 1, the rollers 50 contact the outer circumferential face of the pressing member 42 of the retainer ring 40. [0072] As shown in FIG. 2, the top ring 10 can be coaxially inserted into the retainer ring 40, which has been correctly positioned on the polishing plate 15, without contact and can be rotated in a direction �B� (see FIG. 3). [0073] Since the retainer ring 40, which has been correctly positioned by the rollers 50, is mounted on the polishing plate 15 rotating in the direction �A�, the retainer ring 40 is rotated in a direction �C� (see FIG. 3) with the rotation of the polishing plate 15 without reference to the rotation of the top ring 10. The pressing face 44 of the pressing member 42 presses the polishing cloth 16 along an outer edge of the wafer �W�, which has been held and pressed onto the polishing cloth 16 by the top ring 10. With this action, level of the polishing cloth 16 pressed by the pressing face 44 of the pressing member 42 is made substantially equal to that of the polishing cloth 16 pressed by the lower surface of the wafer �W�. Namely, the part of the polishing cloth 16 pressed by the pressing member 42 and the part of the polishing cloth 16 pressed by the wafer �W� can be substantially included in the same horizontal plane. [0074] In FIG. 3, the top ring 10 and the retainer ring 40 are rotated in the same direction, but the both are independently rotated, so that their rotational speed can be easily respectively changed. By rotating the both with different rotational speed, positional relationship between a prescribed position in the pressing face 44, which presses the polishing cloth 16, and a prescribed position in the wafer �W�, which presses the polishing cloth 16, is continuously changed. By changing the relationship, even if there are very fine projections in the pressing face 44 of the pressing member 42, bad influences caused by the fine projections can be dispersed and much reduced, so that accuracy of polishing the wafer �W� can be improved. [0075] Note that, if positioning the retainer ring 40 is not required, the rollers 50 may be moved outside of the polishing plate 15 by rotating the shaft 52. [0076] In FIG. 3, the retainer ring 40 is correctly positioned by two rollers 50; in FIG. 4, the retainer ring 40 is correctly positioned by a center roller 56 and one roller 50 attached to the arm 54, which is extended from the rotary shaft 52 rotatably attached to the base section and located outside of the polishing plate 15. [0077] The center roller 56 and the roller 50 contact the outer circumferential face of the pressing member 42 of the retainer ring 40, which is moved with the rotation �A� of the polishing plate 15, at two points so as to correctly position the retainer ring 40 at a prescribed position. While positioning the retainer ring 40, the center roller 56 is rotated in the direction �D�. [0078] In FIGS. 1-4, the weights 48 are mounted on the pressing member 42, whose pressing face 44 presses the polishing cloth 16. On the other hand, a retainer ring 60 shown in FIG. 5 includes: the pressing member 42 having the pressing face 44 for pressing; and a cylindrical member 62 integrated with the pressing member 42. [0079]FIG. 5 is a sectional view of the head section of the polishing machine of a second embodiment. Pressing force of the pressing member 42, which presses the polishing cloth 16 can be adjusted by fitting the weights 48 on an outer circumferential face of the cylindrical member 62 of the retainer ring 60. The top ring 10 is inserted in the retainer ring 60, and there is formed a gap between an inner circumferential face of the cylindrical member 62 and an outer circumferential face of the top ring 10. [0080] A plurality of spherical bodies 64 are provided between the inner circumferential face of the cylindrical member 62 and the outer circumferential face of the top ring 10. The spherical bodies 64 simultaneously contact both circumferential faces. With this structure, the top ring 10, which is rotated with the rotary shaft 12, and the retainer ring 60, which is mounted on the polishing cloth 16 of the polishing plate 15, can be rotated without contact. Preferably, the spherical bodies 64 are made of a corrosion-resistive metal, e.g., stainless steel, titanium or chemical-resistive resin, e.g., acryl, so as to prevent corrosion caused by slurry or moisture. [0081] By providing the spherical bodies 64, the members for positioning the retainer ring 40, e.g., the rollers 50, etc. (see FIGS. 1-4), are not required in the second embodiment. [0082] Note that, the structure of the top ring 10 shown in FIG. 5 is equal to that of the top ring shown in FIG. 1, so the elements shown in FIG. 1 are assigned the same symbols and explanation will be omitted. [0083] In the retainer ring 40 shown in FIGS. 1-4, the top ring 10 and the retainer ring 40 are not connected. Therefore, means for conveying the retainer ring 40 is required when the retainer ring 40 is mounted on and removed from the polishing cloth 16 of the polishing plate 15. [0084] On the other hand, in the second embodiment shown in FIG. 5, means for engaging the top ring 10 with the retainer ring 60 is provided, so that they are mutually engaged when the lower surface of the wafer �W� held by the top ring 10 is upwardly moved away from the polishing cloth 16. Therefore, no means for conveying the retainer ring 60 to a prescribed position on the polishing cloth 16 is required. [0085] In FIG. 5, the engaging means comprises: recesses 66 formed in the outer circumferential face of the cylindrical member 62 of the retainer ring 60; and hooks 70 provided to the top ring 10. The hooks 70 respectively have projections 68, each of which is capable of engaging with each recess 66. [0086] In the present embodiment, a plurality of the engaging means are provided, and the recesses 66 and the projections 68 of the hooks 70 are disengaged while the lower surface of the wafer �W� held by the top ring 10 contacts the polishing cloth 16. [0087] On the other hand, when the top ring 10 is upwardly moved and the lower surface of the wafer �W� is moved away from the polishing cloth 16, the projections 68 of the hooks 70 respectively engage with the recesses 66, so that the retainer ring 60 can be upwardly moved together with the top ring 10. [0088] Note that, the hook 70 may be moved to a position 70′, which is shown by one-dot chain lines in FIG. 5, so as to securely disengage the projection 68 and the recess 68 while the lower surface of the wafer �W� contacts the polishing plate 16. [0089] In the top ring 10 shown in FIGS. 1-5, the holding plate 22 is suspended by the donut-shaped elastic sheet 20 so as to allow the holding plate 22 to project from and retract into the concave part 18 of the main body section 14. To properly limit extension of the elastic sheet 20, the elastic sheet 20 is reinforced by a cloth-like reinforcing member. [0090] However, deformation of the reinforcing member caused by external force parallel to warps and woofs is small, but deformation caused by external force diagonal to the warps and the woofs is great. Therefore, degree of extension of the elastic sheet 20 is also varied by the direction of the force applied to the elastic sheet 20. [0091] Since the holding plate 22 is suspended by the elastic sheet 20, whose degree of extension is varied by the direction of the force applied thereto, the movement of the holding plate 22 is varied by external force applied while rotating. If a gravity center of the wafer �W� is displaced from a rotational center thereof while the wafer �W� held by the holding plate 22 is rotated and polished with the pressing force, the outer edge of the wafer �W� is diagonally abraded. [0092] In the top ring 10 shown in FIG. 1 or 5, a plurality of spherical bodies 36 are provided between the outer circumferential face of the holding plate 22 and the inner circumferential face of the concave part 18 of the main body section 14, and they simultaneously contact the both circumferential faces. With this structure, the gravity center and the rotational center of the wafer �W� can be corresponded while polishing the wafer �W�. [0093] In the head section shown in FIG. 1, the movement of the holding plate 22 in the radial direction of the concave part 18 of the main body section 14 can be prevented by the spherical bodies 36. Therefore, the gap between the outer circumferential face of the holding plate 22 and the inner circumferential face of the retainer ring 40 can be made shorter. [0094] The spherical bodies 36 are provided on the inner side of the elastic sheet 20, so that they can be separated from the slurry supplied onto the polishing cloth 16. Since the spherical bodies 36, which contact each other, simultaneously contact the outer circumferential face of the holding plate 22 and the inner circumferential face of the concave part 18 of the main body section 14, the movement of the holding plate 22 in the radial direction can be securely prevented, so that the holding plate 22 can be smoothly projected from and retracted into the concave part 18 of the main body section 14. [0095] Preferably, the spherical bodies 36 are made of a corrosion-resistive metal, e.g., stainless steel, titanium or chemical-resistive resin, e.g., acryl, so as to prevent corrosion caused by moisture in the space 24. [0096] In the top ring 10 shown in FIGS. 1-5, the holding plate 22 and the pressing member 42 of the retainer ring 40 or 60 are independently rotated, so a gap 45 is formed between the outer circumferential face of the holding plate 22 and the inner circumferential face of the pressing member 42 (see FIGS. 6A and 6B). If the gap 45 is made narrower, a part of the polishing cloth 16 pressed by the pressing face 44 of the pressing member 42 can be close to a part of the polishing cloth 16 pressed by the wafer �W�. [0097] Since the holding plate 22 and the pressing member 42 are independently rotated, it is impossible to make the gap 45 zero. If vacuum suction is stopped while polishing the wafer �W�, the wafer �W� is held on the holding face of the holding plate 22 by only surface tension of water absorbed in the bucking member 47 (see FIG. 6A). Therefore, the wafer �W� is moved to a position �W� by horizontal force, so that the outer edge of the wafer �W� collides with the inner circumferential face of the pressing member 42 as shown in FIG. 6A. [0098] Preferably, the inner circumferential face of the pressing member is made of or coated with a ceramic or resin so as to prevent damage caused by the collision. [0099] In FIG. 6B, the wafer �W� is held in a template 49, which is provided along the outer edge of the holding plate 22. With this structure, the wafer �W� is not moved on the bucking member 47 even if the wafer �W� is held on the holding face of the holding plate 22 by only the water surface tension. Therefore, the inner circumferential face of the pressing member need not be made of or coated with a ceramic or resin. [0100] Further, if the wafer �W� is held on the holding face of the holding plate 22 by the water surface tension and the vacuum suction while polishing the wafer �W�, the template 49 is not required. [0101] In the case of adhering the wafer �W� on a lower face of a ceramic carrier plate and sucking an upper face of the carrier plate on the lower face of the holding plate 22 while polishing the wafer �W�, no template 49 is not required as well as the example shown in FIG. 6B. [0102] In the embodiments shown in FIGS. 1-6B, the positional relationship between a prescribed position of the wafer �W� and a prescribed position of the retainer ring 40 or 60 are varied maintained while polishing the wafer �W�, so that the bad influence caused by the surface condition of the pressing face 44 of the retainer ring 40 or 60 can be dispersed and much reduced. Namely, the accuracy of polishing the wafer �W� can be improved. [0103] Since the retainer ring 40 or 60 is rotated by the rotation of the polishing plate 15, means for rotating the retainer ring 40 or 60, e.g., a motor, is not required, so that the structure of the polishing machine can be simplified. [0104] In the embodiments shown in FIGS. 1-6B, even if pressing force is not applied to the polishing cloth 16 through the retainer ring 40 or 60, the polishing cloth 16 is pressed by the retainer ring 40 or 60. By continuously pressing the polishing cloth 16 by weight of the retainer ring 40 or 60, the polishing cloth 16 is damaged and the polishing accuracy is badly influenced. [0105] A third embodiment shown in FIG. 7 solves the problem. In the case of applying no pressing force to the polishing cloth 16 through the retainer ring 80, pressing the polishing cloth 16 by the retainer ring 80 can be easily released. FIG. 7 is a sectional view of the head section of the polishing machine of the third embodiment. [0106] In the head section shown in FIG. 7, the top ring 10 is provided to the lower end of the rotary shaft 12, which is vertically moved by the proper elevating means (not shown), e.g., a cylinder unit, and rotated by the proper rotating means (not shown), e.g., a motor. The top ring 10 includes: the main body section 14 fixed to the lower end of the rotary shaft 12; and the holding plate 22 provided in the concave part 18, which is formed in the main body section 14 and whose opening faces the polishing cloth 16 adhered on the upper face of a polishing plate. The holding plate 22 is elastically suspended, by the donut-shaped elastic sheet 20, in the concave part 18, so that the holding plate 22 can be moved in the vertical direction. [0107] In the main body section 14, the space 24 is formed between the inner faces of the concave part 18 and the holding plate 22. Compressed air is supplied into and discharged from the space 24 by the proper pressure means (not shown) via the pipe 26 provided in the rotary shaft 12. When air pressure in the space 24 exceeds elasticity of the elastic sheet 20, the holding plate 22 downwardly projected from the concave part 18. On the other hand, if the air pressure in the space 24 is smaller than the elasticity of the elastic sheet 20, the holding plate 22 is retracted in the concave part 18 by the elasticity. [0108] A ceramic carrier plate 23 is held by the holding plate 22. The wafer �W� is adhered on a lower face of the carrier plate 23 by an adhesive or water surface tension. Namely, the holding face of the holding plate 22 indirectly holds the wafer �W� with the carrier plate 23. [0109] A plurality of the through-holes 28 are formed in the holding plate 22, and their lower ends are opened in the holding face of the holding plate 22. The through-holes 28 are mutually communicated by the communicating space 30. The communicating space 30 is communicated to the proper vacuum means (not shown), e.g., a vacuum pump, via the pipe 32 provided in the rotary shaft 12. With this structure, the carrier plate 23 holding the wafer �W� can be sucked and held on the holding face of the holding plate 22 by actuating the vacuum means. When the vacuum means is stopped, negative pressure in the communicating space 30 is disappeared, so that the carrier plate 23 can be released from the holding face of the holding plate 22. [0110] A ring-shaped member 23 a, whose sectional shape is a triangle, encloses the holding face of the holding plate 22. By the ring-shaped member 23 a, even if horizontal force is applied to the carrier plate 23 while polishing the wafer �W� without sucking the carrier plate 23 by the vacuum pump, the carrier plate 23 can be held on the holding face of the holding plate 22. [0111] In the top ring 10 shown in FIG. 7, the holding plate 22 is suspended by the donut-shaped elastic sheet 20 so as to allow the holding plate 22 to project from and retract into the concave part 18 of the main body section 14. To properly limit extension of the elastic sheet 20, the elastic sheet 20 is reinforced by the cloth-like reinforcing member. [0112] However, deformation of the reinforcing member caused by external force parallel to warps and woofs is small, but deformation caused by external force diagonal to the warps and the woofs is great. Therefore, degree of extension of the elastic sheet 20 is also varied by the direction of the force applied to the elastic sheet 20. [0113] Since the holding plate 22 is suspended by the elastic sheet 20, whose degree of extension is varied by the direction of the force applied thereto, the movement of the holding plate 22 is varied by external force applied while rotating. If the gravity center of the wafer �W� is displaced from the rotational center thereof while the wafer �W� held by the holding plate 22 is rotated and polished with the pressing force, the outer edge of the wafer �W� is diagonally abraded. [0114] In the top ring 10 shown in FIG. 7, a plurality of the spherical bodies 36 are provided between the outer circumferential face of the holding plate 22 and the inner circumferential face of the concave part 18 of the main body section 14, and they simultaneously contact the both circumferential faces. With this structure, the gravity center and the rotational center of the wafer �W� can be corresponded while polishing the wafer �W�. [0115] The movement of the holding plate 22 in the radial direction of the concave part 18 of the main body section 14 can be prevented by the spherical bodies 36. Therefore, the gap between the outer circumferential face of the holding plate 22 and the inner circumferential face of the retainer ring 80 can be made shorter. [0116] The spherical bodies 36 are provided on the inner side of the elastic sheet 20, so that they can be separated from the slurry supplied onto the polishing cloth 16. Since the spherical bodies 36, which contact each other, simultaneously contact the outer circumferential face of the holding plate 22 and the inner circumferential face of the concave part 18 of the main body section 14, the movement of the holding plate 22 in the radial direction can be securely prevented, so that the holding plate 22 can be smoothly projected from and retracted into the concave part 18 of the main body section 14. [0117] Preferably, the spherical bodies 36 are made of a corrosion-resistive metal, e.g., stainless steel, titanium or chemical-resistive resin, e.g., acryl, so as to prevent corrosion caused by moisture in the space 24. [0118] The top ring 10 is inserted in the retainer ring 80. The top ring 80 includes: the cylindrical member 41 in which the main body section 14 and the holding plate 22 of the top ring 10 are inserted; an extended member 43 extended from a lower end of the cylindrical member 41 toward the carrier plate 23; and the ring-shaped pressing member 42 provided to an inner edge of the extended member 43. The pressing member 42 encloses the carrier plate 23. The projected part 44 or the pressing face for pressing the polishing cloth 16 is downwardly projected along the inner edge of the pressing member 42. [0119] An extended section 51 is inwardly extended from an upper end of the cylindrical member 41. The pins 46 are upwardly extended from the extended section 51, and the ring-shaped weights 48 are piled and correctly positioned by fitting with the pins 46. The weights 48 apply pressing force to the pressing member 42, so that the pressing face 44 is capable of pressing the polishing cloth 16 with proper pressing force. The pressing force is defined on the basis of the pressing force for pressing the wafer �W� onto the polishing cloth 16. The top ring 10 is inserted in the cylindrical member 41 of the retainer ring 80, and there is formed a gap between an inner circumferential face of the cylindrical member 41 and the outer circumferential face of the top ring 10. [0120] A plurality of the spherical bodies 64 are provided between the inner circumferential face of the cylindrical member 41 and the outer circumferential face of the top ring 10. The spherical bodies 64 simultaneously contact both circumferential faces. With this structure, the top ring 10, which is rotated with the rotary shaft 12, and the retainer ring 80, which is mounted on the polishing cloth 16 of the polishing plate 15, can be rotated without contact. Preferably, the spherical bodies 64 are made of a corrosion-resistive metal, e.g., stainless steel, titanium or chemical-resistive resin, e.g., acryl, so as to prevent corrosion caused by slurry or moisture. [0121] The polishing machine shown in FIG. 7 has means for moving the pressing member 42 of the retainer ring 80 to and away from the polishing cloth 16 while the lower surface of the wafer �W� is pressed on the polishing cloth 16 by said top ring 10. [0122] The moving means includes: the extended section 51 extended from the upper end of the cylindrical member 41 of the retainer ring 80 to an upper face of the top ring 10; a balloon member 90 provided between the extended section 51 and the upper face of the top ring 10; and a compressor 72 and a vacuum pump 74, which act as the fluid control means for supplying a fluid (compressed air) into and discharging the fluid from the balloon member 90 via a pipe 76 provided in the rotary shaft 76 and fluid paths 78 formed in the main body section 14. [0123] As shown in FIG. 8, the balloon member 90 is constituted by two donut-shaped elastic sheets 90 a and 90 b, which are made of, for example, rubber. Inner edges of the elastic sheets 90 a and 90 b are fixed to an inner frame 92 a; outer edges thereof are fixed to an outer frame 92 b. A plurality of air inlets 94 a are opened in an inner circumferential face of the inner frame 92 a. The air inlets 94 a are respectively communicated to the paths 78 (see FIG. 7). [0124] The balloon member 90 shown in FIG. 8 is provided between the extended section 51 extended from the cylindrical section 41 toward the upper face of the top ring 10 and the upper face of the top ring 10. When the compressor 72 supplies compressed air into the balloon member 90 via the pipe 76 provided in the rotary shaft 12 and the paths 78 formed in the main body section 14, the balloon member 90 is expanded as shown in FIG. 9, then the balloon member 90 upwardly moves the extended section 51 against the pressing force of the retainer ring 80, which is given by the weights 48, so that the pressing face 44 of the pressing member 42 can be moved away from the polishing cloth 16. [0125] With this structure, pressing the polishing cloth 16 by the pressing member 42 of the retainer ring 80 can be easily stopped while polishing the wafer �W�. Therefore, the retainer ring 80 can release the polishing cloth 16 any time if pressing the polishing cloth 16 is not required. [0126] Since the extended section 51 is extended from the upper end of the cylindrical section 41 of the retainer ring 80 toward the upper face of the top ring 10, the retainer ring 80 is vertically moved with the vertical movement of the top ring 10. [0127] To press the polishing cloth 16 by the retainer ring 80, the compressed air in the balloon member 90 is discharged. By discharging the air, the balloon member 90 contracts, so that the extended section 51 is downwardly moved by the pressing force of the retainer ring 80, then the polishing cloth 16 can be pressed by the pressing face 44 of the pressing member 42 of the retainer ring 80. [0128] While the balloon member 90 is expanded and the pressing face 44 of the pressing member 42 is separated from the polishing cloth 16, the retainer ring 80 and the top ring 10 are rotated, at the same speed, with the balloon member 90. [0129] When the balloon member 90 is contracted to press the polishing cloth 16 by the pressing face 44 of the pressing member 42, the retainer ring 80 is mounted onto the polishing cloth 16 and independently rotated with respect to the top ring 10. [0130] Therefore, preferably, the vacuum pump 74 is driven so as to discharge the air from the balloon member 90 in a short time and form a gap between the balloon member 90 and the extended section 51. [0131] In the polishing machine shown in FIG. 7, the top ring 10 is coaxially inserted in the retainer ring 80 as shown in FIG. 10, and the wafer �W� is mounted onto the polishing plate 15 rotating in the direction �A� so as to polish the lower surface of the wafer �W�. Note that, the rollers 50 (see FIG. 1) for positioning the retainer ring are not required. [0132] The top ring 10 is inserted in the cylindrical member 41 of the retainer ring 80 mounted on the polishing plate 14, so the top ring 10 is rotated in the direction �B� together with the rotary shaft 12. [0133] On the other hand, the retainer ring 80 is mounted on the polishing plate 15 rotating in the direction �A�, the retainer ring 80 is rotated in the direction �C�, with the rotation of the polishing plate 15, without reference to the rotation of the top ring 10. The pressing face 44 of the pressing member 42 presses the polishing cloth 16 along the outer edge of the wafer �W� pressed onto the polishing cloth 16 by the top ring 10. With this action, level of the polishing cloth 16 pressed by the pressing face 44 of the pressing member 42 is made substantially equal to that of the polishing cloth 16 pressed by the lower surface of the wafer �W�. Namely, the part of the polishing cloth 16 pressed by the pressing member 42 and the part of the polishing cloth 16 pressed by the wafer �W� can be substantially included in the same horizontal plane. [0134] In FIG. 10, the top ring 10 and the retainer ring 80 are rotated in the same direction, but they are independently rotated, so that their rotational speed can be easily respectively changed. By rotating the top ring 10 and the retainer ring 80 at different rotational speed, the positional relationship between a prescribed position in the pressing face 44, which presses the polishing cloth 16, and a prescribed position in the wafer �W� held by the top ring 10, which presses the polishing cloth 16, is continuously changed. By changing the relationship, even if there are very fine projections in the pressing face 44 of the pressing member 42 of the retainer ring 80, bad influences caused by the fine projections can be dispersed and much reduced, so that accuracy of polishing the wafer �W� can be improved. [0135] In the polishing machine shown in FIGS. 7-10, the wafer �W� is indirectly held by the holding plate 22 of the top ring 10 with the carrier plate 23, but the wafer �W� may be directly held by the holding plate 22 of the top ring 10 as shown in FIG. 11. The wafer �W� is directly held by producing negative pressure in the communicating space 30, which is communicated to the through-holes 28 whose lower ends are opened in the holding face of the holding plate 22. The negative pressure can be produced by proper vacuum means, e.g., a vacuum pump. To release the wafer �W� from the holding plate 22, the vacuum means is stopped, then the negative pressure is disappeared, so that the wafer �W� can be released. [0136] Note that, the wafer �W� may be held on the holding plate 22 by the negative pressure and the surface tension of water absorbed in the bucking member, e.g., unwoven cloth, adhered on the holding face of the holding plate 22. Namely, the holding plate 22 may directly or indirectly hold the wafer �W� on the holding face. In the case of using the water surface tension, the wafer �W� may be held on the holding plate 22 by the water surface tension only while polishing the wafer Note that, the structures of the top ring 10 and the retainer ring 80 shown in FIG. 11 are equal to those of the top ring and the retainer ring shown in FIG. 7, so the elements shown in FIG. 7 are assigned the same symbols and explanation will be omitted. [0137] In the polishing machine shown in FIGS. 7-11, the positional relationship between the prescribed position in the pressing face 44, which presses the polishing cloth 16, and the prescribed position in the wafer �W�, which presses the polishing cloth 16, is continuously changed as well as the polishing machine shown in FIGS. 1-6B. By changing the relationship, even if there are very fine projections in the pressing face 44 of the pressing member 42 of the retainer ring 80, bad influences caused by the fine projections can be dispersed and much reduced, so that accuracy of polishing the wafer �W� can be improved. [0138] Further, the retainer ring 80 is rotated by the rotation of the polishing plate 15, no rotating means, e.g., a motor, for rotating the retainer ring 80 is required, so that the structure of the polishing machine can be simplified. The balloon member 90, which acts as the moving means, is capable of moving the pressing member 42 of the retainer ring 80 close to and away from the polishing cloth 16 while the wafer �W� is pressed onto the polishing cloth 16 by the top ring 10. The pressing face 44 of the pressing member 42 of the retainer ring 80 can be pressed onto the polishing cloth 16 when pressing the polishing cloth 16 is required. Therefore, span of life of the polishing cloth 16 can be extended, and the accuracy of polishing the wafer �W� can be improved. The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by he foregoing description and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Referenced byCiting PatentFiling datePublication dateApplicantTitleUS7094139Sep 8, 2003Aug 22, 2006Applied Materials, Inc.Retaining ring with flange for chemical mechanical polishingUS7677958Aug 17, 2006Mar 16, 2010Applied Materials, Inc.Retaining ring with flange for chemical mechanical polishingUS7934979Jan 14, 2010May 3, 2011Applied Materials, Inc.Retaining ring with tapered inner surfaceClassifications U.S. Classification451/287, 451/402International ClassificationB24B37/32, B24B37/30, B24B37/04Cooperative ClassificationB24B37/32, B24B37/30European ClassificationB24B37/32, B24B37/30Legal EventsDateCodeEventDescriptionSep 3, 2013FPExpired due to failure to pay maintenance feeEffective date: 20130712Jul 12, 2013LAPSLapse for failure to pay maintenance feesFeb 25, 2013REMIMaintenance fee reminder mailedSep 30, 2008FPAYFee paymentYear of fee payment: 4RotateOriginal ImageGoogle Home - Sitemap - USPTO Bulk Downloads - Privacy Policy - Terms of Service - About Google Patents - Send FeedbackData provided by IFI CLAIMS Patent Services©2012 Google