Abstract: An apparatus for processing wafer is provided, in which a re-adhesion of the slurry to the wafer edge, which has been adhered to the elastic abrasion member, can be inhibited, since a stronger contact of the rotating elastic abrasion member with the wafer edge, which is occurred when the rotating elastic abrasion member enters to the surface of the wafer, is avoided, and further, an abrasion of the elastic abrasion member can be inhibited.

Abstract: An edge control system for deployment on a CMP carrier head comprising a bladder and a carrier head housing having a passage extending therethrough. The bladder includes a flexible diaphragm and is coupled to the carrier head housing. The edge control system comprises first and second annular ribs, each of which comprises a first end portion sealingly coupled to the carrier head housing, a second end portion coupled to the diaphragm, and a strain relief member substantially intermediate the first end portion and the second end portion. A plenum is substantially defined by the first and second annular ribs and the carrier head housing. The passage is fluidly coupled to the plenum to permit the pressurization of the plenum, and the strain relief member promotes the extension of the first and second annular ribs away from the carrier head housing when the plenum is pressurized.

Abstract: In order to achieve the above object, the invention provides a retainer ring for polishing head includes: a base unit made of a highly rigid material, formed to have a ring-like shape, and supported on the polishing head side; and a resin unit in which a plurality of resin blocks are fixed to the lower surface of the base unit at almost the same intervals and which serves as a contact side to the polishing pad. Flow paths for the slurry are constituted by spaces between adjacent resin blocks and the lower surface of the base unit.

Abstract: A method and device for effecting automatic centering of an annular workpiece on a rotating surface having a rotational center involves arbitrarily positioning the workpiece on the slowly rotating surface, applying a support for the workpiece by way of spaced apart contact members that individually contact the workpiece and are synchronously movable in a guided reciprocating manner towards and away from the rotational center of the rotating surface. The contact members are gradually retracted away from the rotational center of the rotating surface until the workpiece is unaffected by the contact members during one revolution of the rotating surface so that the workpiece is centered, and the center of the workpiece coincides with the rotational center of the rotating surface. At least one of the contact members is provided with a mechanism for counteracting a friction force acting on the workpiece.

Abstract: A carrier head that has a base assembly, a retaining ring assembly, a carrier ring, and a flexible membrane is described. The flexible membrane has a main portion and an outer annular portion, wherein a junction between the main portion and the outer annular portion comprises a peripheral edge hinge and an annular recess above the hinge along the outer wall of the outer annular portion.

Abstract: Retaining rings and associated planarizing apparatuses, and related methods for planarizing micro-device workpieces are disclosed herein. A carrier head configured in accordance with one embodiment of the invention can be used to retain a micro-device workpiece during mechanical or chemical-mechanical polishing. In this embodiment, the carrier head can include a retaining ring carried by a workpiece holder. The retaining ring can include an inner surface, an outer surface, and a base surface extending at least partially between the inner and outer surfaces. The retaining ring can further include at least one annular groove and a plurality of transverse grooves. The annular groove can be positioned adjacent to the base surface between the inner and outer surfaces. The plurality of transverse grooves can extend from the inner surface of the retaining ring to the annular groove in the base surface.

Abstract: A retaining ring can be shaped by machining or lapping the bottom surface of the ring to form a shaped profile in the bottom surface. The bottom surface of the retaining ring can include flat, sloped and curved portions. The lapping can be performed using a machine that dedicated for use in lapping the bottom surface of retaining rings. During the lapping the ring can be permitted to rotate freely about an axis of the ring. The bottom surface of the retaining ring can have curved or flat portions.

Abstract: The present invention related to a loading device for a chemical mechanical polisher of semiconductor wafers comprising: a loading cup on wherein a cup plate is installed in a cup-shaped bath, a loading plate for receiving wafers sits on the cup plate, and a plurality of vertical damping devices lie between the cup plate and the loading plate so as for the loading plate to be damped in a vertical direction; a driving axis for a right and left pivot movement and an ascending and descending movement of the loading cup between a platen of the chemical mechanical polisher and a spindle; and an arm connecting the loading cup to the driving axis; wherein a plurality of horizontal damping devices are positioned with a constant angle in a radial direction along a bottom surface of the loading plate from its center in order for a polishing carrier head mounted on the spindle and the loading plate to be detachable after being calibrated to a normal position by shaking the loading plate finely in a horizontal direction

Abstract: A carrier head for supporting a workpiece is provided. The carrier head comprises a mount plate having an aperture therethrough, and a clamp ring having a foot portion and a first leg portion extending therefrom. The first leg portion extends through the aperture, and the foot portion abuts the mount plate proximate the aperture. A flexible bladder has first and second ribs that are received between the mount plate and the foot portion. An annular fastener is removably coupled to the leg portion, and engages the mount plate to cause the first and second ribs to be sealingly secured between the mount plate and the foot portion.

Abstract: The invention provides a vertically adjustable chemical mechanical polishing head having a pivot mechanism and method for use thereof.

Abstract: Retaining rings and associated planarizing apparatuses, and related methods for planarizing micro-device workpieces are disclosed herein. A carrier head configured in accordance with one embodiment of the invention can be used to retain a micro-device workpiece during mechanical or chemical-mechanical polishing. In this embodiment, the carrier head can include a retaining ring carried by a workpiece holder. The retaining ring can include an inner surface, an outer surface, and a base surface extending at least partially between the inner and outer surfaces. The retaining ring can further include at least one annular groove and a plurality of transverse grooves. The annular groove can be positioned adjacent to the base surface between the inner and outer surfaces. The plurality of transverse grooves can extend from the inner surface of the retaining ring to the annular groove in the base surface.

Abstract: A resilient pneumatic annular sealing bladder is coupled for fluid communication to a first pressurized pneumatic fluid to define a first pneumatic zone and is attached to a first surface of the wafer stop plate adjacent the retaining ring interior cylindrical surface to receive the wafer and to support the wafer at a peripheral edge. The resilient pneumatic annular sealing bladder defines a second pneumatic zone radially interior to the first pneumatic zone and extends between the first surface of the wafer stop plate and the wafer when the wafer is attached to the polishing head during a polishing operation and is coupled for fluid communication to a second pressurized pneumatic fluid. The wafer attachment stop plate is operative during non polishing periods to prevent the wafer from flexing excessively from an applied vacuum force used to hold the wafer to the polishing head during wafer loading and unloading operations.

Abstract: A polishing apparatus comprises a polishing table having a polishing surface and a top ring for holding a substrate to be polished, in which the substrate when held by the top ring is pressed against the polishing surface of the polishing table and thus polished. A capacitance type sensor and/or an eddy-current type sensor is disposed at one or more location(s) in the vicinity of the top ring. The capacitance type sensor detects escaping of the substrate to be polished based on a change in capacitance between the capacitance type sensor and a top surface of the polishing table. The eddy-current type sensor detects escaping of the substrate to be polished based on a change in electrical resistance between the eddy-current type sensor and the top surface of the polishing table.

Abstract: A pedestal pad (workpiece supporting table pad) is arranged on the top of a pedestal (workpiece supporting table) for temporarily placing and holding a pre-polished or post-polished wafer (workpiece). This pedestal pad is formed of resin, and at least a surface of the pedestal pad which comes into contact with the wafer is non-absorbable to a fluid. The tissue of the pedestal pad is dense and smooth, and does not have any cavity, such as fine holes, which holds the fluid.

Abstract: A carrier head for chemical mechanical polishing that has a base having at least a portion formed of a polymer, a mounting assembly connected to the base having a surface for contacting a substrate, a retainer secured to the portion of the base to prevent the substrate from moving along the surface, and a dampening material secured between the retainer and the base.

Abstract: A carrier head for chemical mechanical polishing of a substrate includes a base and a flexible membrane extending beneath the base. The flexible membrane includes a central portion with an outer surface providing a substrate receiving surface, a perimeter portion connecting the central portion to the base, and at least one flap extending from an inner surface of the central portion. The flap divides a volume between the flexible membrane and the base into a plurality of chambers, and the flap includes a laterally extending first section and an angled second section extending beneath the first section and connecting the laterally extending first section to the central portion.

Abstract: The polishing apparatus is capable of precisely controlling polishing pressure, correctly positioning a press plate and uniformly polishing a workpiece. In the polishing apparatus, a holding head comprises: first pressing means for introducing a pressurized fluid into a first fluid chamber and pressing a main head section downward; second pressing means for introducing a pressurized fluid into a second fluid chamber and pressing a press plate downward; and third pressing means for introducing a pressurized fluid into a third fluid chamber and pressing the workpiece downward. With this structure, the workpiece is held on the lower side of an elastic sheet member, and the lower face of the workpiece can be polished by a polishing plate.

Abstract: An apparatus for polishing a wafer comprises a supporting portion having an abrasive pad disposed thereon, and a polishing head disposed over the abrasive pad. The polishing head comprises a carrier having at least two fluid passages, a retainer ring disposed on a lower edge of the carrier, forming a space for receiving the wafer, a supporter disposed in the carrier, and a flexible membrane disposed to be in contact with the wafer. The supporter has an upper surface portion, a lower surface portion, a plurality of first holes, a plurality of second holes, and a first chamber. The upper surface portion of the supporter forms a second chamber along with an inner surface of the carrier. The second chamber is in communication with one of the two fluid passages of the carrier and the second holes are formed in a lower surface portion of the supporter to communicate with the second chamber.

Abstract: The invention refers to a polishing tool for optical lenses with at least one polishing pad adaptable at least partially to the shape of a lens surface of said lenses and drivable by means of a drive shaft, said polishing pad having a membrane, wherein said polishing pad can transmit a bearing force of said membrane at least in an orthogonal direction relative to a lens surface. Moreover, the polishing tool comprises a reinforcing member connectable to said membrane, said reinforcing member being dimensionally stable in a parallel direction relative to a surface of said membrane and being flexible and/or pliable in an orthogonal direction relative to the surface of said membrane, wherein at least one pressure pad with a pressure membrane is arranged within said polishing pad, wherein said pressure membrane can be made to bear and/or can be prestressed against said membrane or said reinforcing member in an indirect or in a direct manner.

Abstract: The present invention relates to an apparatus and method for polishing semiconductor substrates with improved throughput. Embodiments of the present invention eliminate load cups from a polishing system, hence improve throughput by reducing system footprint and substrate hand off. One embodiment provides an apparatus for polishing a substrate. The apparatus comprises a platen having a polishing pad supported thereon, a carrier head configured to hold the substrate and press the substrate against the polishing pad, and a retaining ring adapted to be attached to and detached from the carrier head, wherein the retaining ring is configured to receive the substrate while positioned on the polishing pad and detached from the carrier head.

Abstract: A flexible membrane for use with a carrier head of a substrate chemical mechanical polishing apparatus has a central portion with an outer surface providing a substrate receiving surface, a perimeter portion for connecting the central portion to a base of the carrier head, and at least one flap extending from an inner surface of the central portion. The flap includes a laterally extending first section and a vertically extending second section connecting the laterally extending first section to the central portion.

Abstract: Disclosed is an electrostatic chuck and system for maintaining a device flat within the electrostatic chuck. The electrostatic chuck has a plate, height adjustment mechanisms connected to the plate; and electrostatic chuck pins connected to the height adjustment mechanisms. The system provides a measurement tool adapted to measure the flatness of the device held by the electrostatic chuck pins and a computer connected to the height adjustment mechanisms and the measurement tool. The computer adjusts the flatness of the device by adjusting the height adjustment mechanisms based on feedback from the measurement tool. The computer is adapted to change the shape of the device to conform to a pre-existing standard.

Abstract: The present invention relates to a polishing apparatus for polishing a workpiece such as a semiconductor wafer to a flat mirror finish, and more particularly to a polishing apparatus having a workpiece transfer robot for transferring a workpiece from one operation to the next. The polishing apparatus according to the present invention comprises a polishing section including a top ring for holding a workpiece to be polished and a turntable having a polishing surface for polishing a surface of the workpiece held by the top ring; a cleaning section including a cleaning device for cleaning the workpiece that has been polished in the polishing section; and a workpiece transfer robot for transferring the workpiece to be polished to the polishing section or for transferring the workpiece that has been polished to the cleaning section.

Abstract: Retaining rings, planarizing apparatuses including retaining rings, and methods for mechanical and/or chemical-mechanical planarization of micro-device workpieces are disclosed herein. In one embodiment, a carrier head for retaining a micro-device workpiece during mechanical or chemical-mechanical polishing includes a workpiece holder configured to receive the workpiece and a retaining ring carried by the workpiece holder. The retaining ring includes an inner surface, an outer surface, a first surface between the inner surface and the outer surface, and a plurality of grooves in the first surface extending from the inner surface to the outer surface. The grooves include at least a first groove and a second groove positioned adjacent and at least substantially transverse to the first groove.

Abstract: A two part retaining ring is described that has a lower ring and an upper ring. The lower ring contacts a polishing surface during chemical mechanical polishing. The upper surface and the lower surface of the lower ring have matching grooves formed therein to increase the flexibility of the lower ring.

Abstract: The present invention provides a polishing apparatus for a semiconductor wafer in which a slide member and a swing holding member are provided in a polishing member that is provided so as to block an opening in a head housing, a slide guide member and a ring member are provided in the head housing, the ring member surrounds the periphery of the polishing member positioned in the head housing such that a predetermined clearance is formed between the ring member and the outer peripheral portion of the polishing member, and the polishing member is constituted to be capable of a reciprocating motion using air that is supplied into and discharged from the head housing. By means of this constitution, the present invention provides a polishing apparatus in which the linearity between a polishing thrust and air pressure in the head housing is increased.

Abstract: A flexible membrane for a polishing head and a chemical mechanical polishing (CMP) apparatus having the same are provided. The flexible membrane for a polishing head includes a compressing plate having a first face and a second face opposite to the first face. The first face of the compressing plate holds a substrate with a vacuum provided thereto and compresses the substrate on a polishing pad. The second face of the compressing plate is combined with a supporter of the polishing head. The second face and the supporter define a space to which the vacuum for holding the substrate and a first pneumatic pressure for compressing the substrate are applied. A dividing member combined with the supporter is formed on the second face. The dividing member divides the space into at least two regions. A pneumatic pressure-introducing portion is formed at the dividing member. A second pneumatic pressure is provided to the compressing plate through the pneumatic pressure-introducing portion.

Abstract: The carrier head has a base and a substrate backing structure for holding a substrate against a polishing surface during polishing. The substrate backing structure is connected to the base and includes an external surface that contacts a backside of the substrate during polishing. The substrate backing structure also includes a resistive heating system to distribute heat over an area of the external surface and at least one thermally conductive membrane. The external surface is a first surface of the at least one thermally conductive membrane, and the resistive heating system is integrated within one of the at least one thermally conductive membrane.

Abstract: An apparatus for planarizing a work piece includes an easily assembled work carrier. The carrier includes a carrier insert having a work piece bladder clamped to a carrier backing plate with a plurality of clamps to form a plurality of web plenums. The outer edge of the bladder is supported by a rib that is coupled to a carrier plenum. By adjusting the pressure in the carrier plenum, the pressure exerted on the edge of a work piece during a planarization operation can be adjusted. The carrier also includes a floating wear ring that surrounds the work piece bladder and a work piece mounted on that bladder. By adjusting the force exerted by the wear ring on a polishing pad, independently of the pressure exerted by the rib at the edge of the bladder, the material removal rate near the edge of the work piece can be controlled.

Abstract: A cutting tool having a crystalline tip is pressed with a uniform pressure against the outboard surface of a vehicle wheel as the wheel is rotated. The smoothed wheel surface is then chrome plated to provide a cosmetic finish to the wheel face.

Abstract: A wafer polishing apparatus for polishing a semiconductor wafer. The polisher comprises a base (23), a turntable (27), a polishing pad (29) and a drive mechanism (45) for driven rotation of a polishing head (63). The polishing head is adapted to hold at least one wafer (35) for engaging a front surface of the wafer with a work surface of the polishing pad. A spherical bearing assembly (75) mounts the polishing head (63) on the drive mechanism for pivoting of the polishing head about a gimbal point (p) lying no higher than the work surface when the polishing head holds the wafer in engagement with the polishing pad. This pivoting allowing the plane of the front surface of the wafer to continuously align itself to equalize polishing pressure over the front surface of the wafer, while rotation of the polishing head is driven by the driving mechanism.

Abstract: A retaining ring having a bottom portion that is removable from the ring's upper portion is described. The upper and lower portions of the retaining ring include one or more magnetic bodies and/or one or more bodies formed of a material that is attracted to magnets.

Abstract: Disclosed is a carrier head of a chemical mechanical polishing apparatus for planarizing a semiconductor wafer. An adjustment chamber is provided in a space section formed between a membrane lower holder and a membrane upper holder of a wafer support assembly. Pressure applied to the adjustment chamber is transferred to a rear surface of a membrane during a polishing process through a perforated hole formed at a center of the membrane lower holder. A center portion of the membrane is connected to a vacuum pipe by passing through a hole of the membrane lower holder and the adjustment chamber. Vacuum pressure is directly applied to a wafer so that the wafer is easily attached to the carrier head at lower pressure. Pressure is evenly distributed over the whole area of the wafer so that the wafer is evenly polished.

Abstract: A polishing apparatus is provided for removing material from a surface of a substrate. The apparatus includes a polishing head for positioning a surface of a substrate against a polishing surface of the apparatus. The polishing head includes a subcarrier adapted to hold the substrate during a polishing operation, and a retaining ring having an inner edge disposed about the subcarrier and a lower surface in contact with the polishing surface during the polishing operation, the lower surface of the retaining ring having a number of radial recesses formed therein to distribute a chemical between the substrate held on the subcarrier and the polishing surface when there is relative motion between the substrate and the polishing surface, thereby inhibiting non-planar polishing of the surface of the substrate.

Abstract: The present invention relates to a substrate holding apparatus for holding a substrate such as a semiconductor wafer in a polishing apparatus for polishing the substrate to a flat finish. The substrate holding apparatus includes a vertically movable top ring body for holding the substrate, and an elastic membrane for defining a pressure chamber in the top ring body. A coating is applied to a surface of the elastic membrane which is brought into contact with the substrate.

Abstract: A carrier head includes a housing connectable to a drive shaft to rotate therewith, a lower assembly having a substrate mounting surface, and a gimbal mechanism that connects the housing to the lower assembly to permit the lower assembly to pivot with respect to the housing about an axis substantially parallel to the polishing surface. The gimbal mechanism includes a shaft having an upper end slidably disposed in a vertical passage in a vertical passage in the housing, and a lower member that connects a lower end of the shaft to the lower assembly. The lower member bends to permit the base to pivot with respect to the housing. The shaft and the lower member are a unitary body.

Abstract: A wafer polishing head utilizes a wafer backing member having a wafer facing pocket which is sealed against the wafer and is pressurized with air or other fluid to provide a uniform force distribution pattern across the width of the wafer inside an edge seal feature at the perimeter of the wafer to urge (or press) the wafer uniformly toward a polishing pad. Wafer polishing is carried out uniformly without variations in the amount of wafer material across the usable area of the wafer. A frictional force between the seal feature of the backing member and the surface of the wafer transfers rotational movement of the head to the wafer during polishing. A pressure controlled bellows supports and presses the wafer backing member toward the polishing pad and accommodates any dimensional variation between the polishing head and the polishing pad as the polishing head is moved relative to the polishing pad.

Abstract: When a wafer is pressed on a rotating polishing pad and its surface is polished, a retainer retains the periphery of the wafer to prevent the wafer from being detached from the polishing pad. The retainer includes a first ring which surrounds the wafer and contacts the polishing pad and a second ring which is provided outside the first ring in the radial direction of the wafer and contacts the polishing pad. The second ring has wear resistance that is higher than that of the first ring.

Abstract: A retaining ring has a generally annular body with a top surface, a bottom surface, an inner diameter surface, and an outer diameter surface. The outer diameter surface includes an outwardly projecting flange having a lower surface, and the bottom surface includes a plurality of channels.

Abstract: An apparatus for polishing a wafer comprises a supporting portion having an abrasive pad disposed thereon, and a polishing head disposed over the abrasive pad. The polishing head comprises a carrier having at least two fluid passages, a retainer ring disposed on a lower edge of the carrier, forming a space for receiving the wafer, a supporter disposed in the carrier, and a flexible membrane disposed to be in contact with the wafer. The supporter has an upper surface portion, a lower surface portion, a plurality of first holes, a plurality of second holes, and a first chamber. The upper surface portion of the supporter forms a second chamber along with an inner surface of the carrier. The second chamber is in communication with one of the two fluid passages of the carrier and the second holes are formed in a lower surface portion of the supporter to communicate with the second chamber.

Abstract: A polishing carrier head including a retaining ring for defining an area of a polishing pocket region used to polish a predetermined object, is provided. The polishing carrier head may further include a perforated plate positioned lateral to the retaining ring, the perforated plate having a plurality of perforations for permitting fluid flow. The polishing carrier head may further include a flexible membrane having a first region overlying a portion of the retaining ring and the perforated plate and a second region in which a first portion of the flexible membrane overlies a second portion of the flexible membrane to form one or more bellows. The polishing carrier head may further include an edge support ring in contact with the first region of the flexible membrane for clamping the first region of the flexible membrane to the perforated plate.

Abstract: Polishing apparatus and related methods employ aligned first and second magnetic field sources to adjust the compressive force and/or pressure applied by a carrier head against a target workpiece (such as a wafer) by selectively and controllably generating a repellant or attractive force between the two magnetic field sources.

Abstract: A long-lasting retaining ring for wafer carriers used in chemical mechanical planarization. A groove is disposed around the retaining ring, with the groove opening facing the mounting plate. A ridge is disposed in the groove. A bladder is disposed in the groove and is pressed between the ridge and the mounting plate. Pressure in the bladder can be maintained or adjusted to deform the bladder and thereby force the retaining ring onto the polishing pad as the retaining ring is worn. Prior to adding pressure to the bladder, the ridge forces the bladder to very closely conform to the dimensions of the groove. Thus, during use, bladder deformation is not wasted on conforming the bladder to the groove shape, but instead can be used to force the retaining ring further in the direction of the pad. The ridge thereby increases the distance the retaining ring can move towards the pad.

Abstract: A wafer carrier for controlling the edge effect during chemical mechanical planarization. A first bladder is disposed within the retaining ring to control the height of the retaining ring relative to the bottom surface of the wafer carrier. A second bladder is disposed within the carrier such that if the pressure in the bladder is regulated, the amount of force on the edge of the wafer changes. If a polishing process would cause material near the edge of the wafer to be removed at a higher rate than from the rest of the wafer, then the pressure is regulated within the bladder to reduce the force against the edge of the wafer. By reducing the force against the edge of the wafer, material is removed from the front side of the wafer at a uniform rate.

Abstract: A wafer polisher, wherein a retainer ring (28) is installed in a wafer holding head (14), a protective sheet material (52) is disposed inside the retainer ring (28), and a wafer (W) is pressed against a polishing pad (20) through the protective sheet material (52) for polishing, whereby the protective sheet material (52) can be disposed without causing wrinkles on the inner peripheral part of the retainer ring (28).

Abstract: Planarizing machines, carrier heads for planarizing machines and methods for planarizing microelectronic-device substrate assemblies in mechanical or chemical-mechanical planarizing processes. In one embodiment of the invention, a carrier head includes a backing plate, a bladder attached to the backing plate, and a retaining ring extending around the backing plate. The backing plate has a perimeter edge, a first surface, and a second surface opposite the first surface. The second surface of the backing plate can have a perimeter region extending inwardly from the perimeter edge and an interior region extending inwardly from the perimeter region. The perimeter region, for example, can have a curved section extending inwardly from the perimeter edge of the backing plate or from a flat rim at the perimeter edge. The curved section can curve toward and/or away from the first surface to influence the edge pressure exerted against the substrate assembly during planarization.

Abstract: A curved surface cutting method in which a surface of a material is cut by a bite to form a specified curved surface, a cutting edge of the bite is provided with a flat section and corner sections at both ends of the flat section; the posture of the cutting edge of the bite is adjusted such that a ridge line along the flat section of the cutting edge of the bite is in parallel with a tangent drawn at the curved surface; and the surface of the material is cut with the cutting edge of the bite retained in the posture while feeding the cutting edge in a predetermined feeding direction, thereby forming a first band-like cut surface having a width corresponding to the width of the cutting edge of the bite.

Abstract: A carrier bead for chemical mechanical polishing of a substrate. The carrier head includes a carrier base, a retaining ring, and a junction connecting the carrier base to the retaining ring. The junction is configured such that vertical movement of the retaining ring is substantially restrained relative to the carrier base. The junction is further configured such that the profile of a bottom surface of the retaining ring is substantially decoupled from flexing and/or expansion of carrier base.

Abstract: A carrier head for supporting a wafer during a chemical mechanical polishing process is provided. In one exemplary implementation, the carrier head may comprise a wear ring, and a slidably movable pressure plate disposed within the wear ring. The pressure plate may be arranged to provide slidable movement relative to the wear ring. This degree of freedom can accommodate height dimensional changes that may occur in the wear ring.

Abstract: A polishing head of a wafer polishing apparatus includes a body, a center supporter installed in a center of the body, a perforated plate including an upper plate and a lower plate that is disposed below the center supporter and has a plurality of thru-holes, a membrane covering the perforated plate, and a moving member for moving the lower plate up and down. By moving the lower plate up and down, the polishing head forcibly recovers an elasticity of the membrane (especially at an edge portion of the membrane).