Abstract: A grinder designed to provide an automatic grinding operation for the manufacture of a semiconductor device wafer. The grinder includes a base, a rotatable index table mounted to the base, and a grinding wheel assembly including a grinding wheel for grinding a flat surface on the wafer. The index table includes a wafer holder for receiving and holding the wafer and a dressing element for dressing the grinding wheel. The index table is selectively rotatable between a grinding position where the wafer is ground by the grinding wheel and a dressing position where the grinding wheel is dressed by the dressing element.

Abstract: A carrier head for chemical mechanical polishing of a substrate includes a base and a flexible membrane extending beneath the base to define a chamber. The flexible membrane has a core of a first material and an outer layer of a second material having a lower adhesion to the substrate than the first material. An exposed surface of the outer layer provides a mounting surface for the substrate.

Abstract: Apparatus and method for reconditioning the protective coating of a digital disc. The damaged digital disc is automatically moved between workstations by a suction member which grasps the disc at the first workstation and releases the disc at the second workstation. Each of the workstations is defined by worktools which operate on the digital disc. A feed cartridge member stores the damaged discs prior to movement of the discs into the first workstation and a receiving cartridge member stores the reconditioned discs following the final reconditioning operations at the last workstation.

Abstract: The present invention provides a wafer carrier that includes an opening, which in one embodiment is a plurality of holes, disposed along the periphery of the wafer carrier. A gas emitted through the holes onto a peripheral back edge of the wafer assists in preventing the processing liquids and contaminants resulting therefrom from reaching the inner region of the base and the backside inner region of the wafer. In another embodiment, a plurality of concentric sealing members are used to prove a better seal, and the outer seal is preferably independently movable to allow cleaning of a peripheral backside of the wafer to occur while the wafer is still attached to the wafer carrier.

Abstract: A carrier head for a chemical mechanical polishing apparatus includes a flexible membrane that applies a controllable load to a substrate in an area with a controllable inner diameter.

Abstract: A polishing apparatus for polishing a substrate comprises a polishing table having a polishing surface, and a substrate holding apparatus for holding a substrate to be polished and pressing the substrate against the polishing surface. The substrate holding apparatus comprises a vertically movable top ring body for holding a substrate, and a fluid supply source for supplying a fluid under a positive pressure or a negative pressure to a hermetically sealed chamber which is defined in the top ring body so as to control pressure under which the substrate is pressed against the polishing surface. The substrate holding apparatus further comprises a measuring device disposed in a fluid passage interconnecting the hermetically sealed chamber and the fluid supply source for measuring a flow rate of the fluid in the fluid passage.

Abstract: The present invention provides a wafer carrier that includes a plurality of concentric sealing members that provide a seal, with the outer seal independently movable to allow cleaning of a peripheral backside of the wafer to occur while the wafer is still attached to the wafer carrier, and a plurality of vacuum openings that a re disposed only adjacent to an inner side of the inner seal at a location corresponding to the backside periphery of the wafer.

Abstract: A carrier head for chemical mechanical polishing of a substrate includes a base and a flexible membrane extending beneath the base to define a chamber. The flexible membrane has a core of a first material and an outer layer of a second material having a lower adhesion to the substrate than the first material. An exposed surface of the outer layer provides a mounting surface for the substrate.

Abstract: An apparatus for grinding center bearings of crankshafts includes a clamping unit for clamping and driving a crankshaft; a grinding spindle, positionable perpendicular to the crankshaft; a plurality of grinding wheels on the grinding spindle, corresponding to the number of center bearings to be ground; a plurality of steadies, for supporting the crankshaft, opposite the grinding spindle; and an additional processing unit for performing preliminary grinding on the center bearing, by forming an elevated bearing seat for the steadies, opposite the bearing, such that the steadies are continuously guidable during grinding of the center bearings. In a method for grinding center bearings of a crankshaft using the apparatus, the center bearings are simultaneously ground using a multilayer grinding wheel set, and prior to a final grinding of the center bearings to their final dimensions, a bearing seat for a steady is ground on at least one center bearing.

Abstract: A wafer grinding apparatus includes a wafer-transporting device for transporting a wafer, a first nozzle, and a second nozzle. The wafer-transporting device includes at least a suction pad having a first surface and a second surface that is flexible for sucking the wafer, and a transporting mechanism connected to the first surface of the suction pad for transporting the wafer. The first nozzle is used for ejecting a first liquid to the first surface of the suction pad for cleaning the first surface, and the second nozzle is used for ejecting a second liquid to the second surface of the suction pad and the wafer for cleaning the second surface and the wafer.

Abstract: Chemical mechanical polishing (CMP) equipment for use in planarizing a semiconductor wafer prevents slurry from being deposited on the surfaces of respective components of the equipment. The CMP equipment includes a turntable, a polishing pad mounted to the table so as to rotate with the table, a slurry supply unit for dispensing slurry onto the polishing pad, a polishing head unit for pressing a wafer downward atop the polishing pad, a conditioning unit for scoring the pad to maintain the surface of the polishing pad uniform, and a cleaning fluid supply unit. The cleaning solution supply unit has at least one spray nozzle by which cleaning solution is sprayed onto the polishing pad and respective components of the CMP equipment.

Abstract: A carrier head for chemical mechanical polishing of a substrate having a front surface, a back surface and an edge. The carrier head has a base, an inner retaining ring positioned beneath the base, and an outer retaining ring surrounding the inner retaining ring to retain the inner retaining ring. The inner retaining ring has a main portion with a first surface to apply a load to a perimeter portion of the back surface of the substrate and an annular lower projection protruding downwardly from the main portion with a second surface to circumferentially surround the edge of the substrate to retain the substrate.

Abstract: A method and apparatus for planarizing a microelectronic substrate. In one embodiment, the apparatus can include a membrane formed from a compressible, flexible material, such as neoprene or silicone, and having a first portion with a thickness greater than that of a second portion. The membrane can be aligned with the microelectronic substrate to bias the microelectronic substrate against a planarizing medium such that the first portion of the membrane biases the microelectronic substrate with a greater downward force than does the second portion of the membrane. Accordingly, the membrane can compensate for effects, such as varying linear velocities across the face of the substrate that would otherwise cause the substrate to planarize in a non-uniform fashion or, alternatively, the membrane can be used to selectively planarize portions of the microelectronic substrate at varying rates.

Abstract: A pedestal of a load-cup for supporting wafers loaded onto and being unloaded from a chemical mechanical polishing (CMP) apparatus includes a pedestal plate, and a pedestal film which extends over only a limited area at the upper surface of the pedestal plate. This area includes the regions directly around the fluid ports provided in the pedestal plate for vacuum-chucking the wafers and spraying deionized water. The pedestal plate may have a cross-shaped part, the entirety of which bears the fluid ports. The pedestal film may include annular members each extending around only a respective one of the fluid ports, or one or more members each extending radially around several of the fluid ports. By offering a rather limited contact area to the wafer supported on the pedestal, the pedestal film reduces the amount of contaminants which could be transferred to the wafer surface in contact therewith.

Abstract: The present invention provides a wafer carrier that includes an opening, which in one embodiment is a plurality of holes, disposed along the periphery of the wafer carrier. A gas emitted through the holes onto a peripheral back edge of the wafer assists in preventing the processing liquids and contaminants resulting therefrom from reaching the inner region of the base and the backside inner region of the wafer. In another embodiment, a plurality of concentric sealing members are used to prove a better seal, and the outer seal is preferably independently movable to allow cleaning of a peripheral backside of the wafer to occur while the wafer is still attached to the wafer carrier.

Abstract: Retaining device (1) for a block or suction element (10) in a centering device for spectacle lenses, having a support, which has a longitudinal axis (2), having a spherically dome-shaped bearing surface (3) on the support, having a spherical dome (5), which is mounted cardanically on the support and is complementary to the bearing surface, having a holding element (6) in the spherical dome for the block or suction element with a contact surface (11) for the spectacle lens, and having a radius (R) of the bearing surface and of the spherical dome, the mid-point (M) of which is located on the longitudinal axis of the support (1) on the contact surface for the spectacle lens.

Abstract: The present invention relates to a substrate holding apparatus for holding a substrate to be polished and pressing the substrate against a polishing surface. The substrate holding apparatus comprises a top ring body for holding a substrate, an elastic pad for being brought into contact with the substrate, and a support member for supporting the elastic pad. The substrate holding apparatus further comprises a contact member mounted on a lower surface of the support member and disposed in a space formed by the elastic pad and the support member. The contact member has an elastic membrane for being brought into contact with the elastic pad. A first pressure chamber is defined in the contact member, and a second pressure chamber is defined outside of the contact member. The substrate holding apparatus further comprises a fluid source for independently supplying a fluid into, or creating a vacuum in, the first pressure chamber and the second pressure chamber.

Abstract: Surface planarization equipment of a semiconductor wafer safely transfers wafers to an unloading cassette. In addition to the unloading cassette, the surface planarization equipment includes a loading cassette configured to hold wafers awaiting surface planarization, an index table including a plurality of first rotary vacuum wafer chucks that receive wafers from the loading cassette, at least one grinding head disposed above the index table and operative to perform a planarization process on the wafers supported by the chucks, a cleaning and drying unit including a second wafer rotary vacuum chuck receiving the wafers from the index table after the planarization process is completed and from which the cleaned and dried wafers are transferred to the unloading cassette. A position detector includes one or more sensors disposed beside respective ones of the vacuum chucks to stop the chucks at desired positions.

Abstract: The wafer polishing apparatus enables the control of proper polishing pressure, so that the quality of wafers can be maintained high. A wafer holding head is composed of a carrier for pressing the wafer against a polishing pad, a retainer ring at the circumference of the carrier, and a holding head body. The holding head body includes a carrier pressing device having an air bag of which pressing surface area is 50% or smaller of the area of the wafer, and the pressing force from the carrier pressing device is transmitted to the carrier.

Abstract: A retaining ring has an inner core of a first material and an outer layer of a second, different material that is deposited on the first material. The outer layer can be deposited by spraying, e.g., by powder coating, and can be a polymer, e.g., polyetheretherketone.

Abstract: An invention is provided for a carrier head for use in a CMP process. The carrier head includes a metal plate that is capable of transferring a downforce to a wafer during a CMP operation. A plurality of vacuum holes is disposed within the metal plate, wherein each vacuum hole is positioned such that the vacuum hole is within five millimeters of an edge of the wafer during the CMP operation. In this manner, each vacuum hole can be positioned such that the vacuum hole is within an edge exclusion zone of the wafer during the CMP operation. In some embodiments, each vacuum hole is positioned such that the vacuum hole is within three millimeters of the edge of the wafer during the CMP operation, such as 2.7 millimeters from the edge of the wafer.

Abstract: A plurality of spaced apart supports are designed to closely support a work piece immediately adjacent the edge being worked, ground or polished. Adjacent shear forced are also eliminated by the use of a polymeric interconnections used to both generally contribute to the spacing and to transmit the vacuum in a distributed manner among the individual support units. The top and bottom surfaces of the supports are dressably machineable in place on the working table to insure that all are brought to exactly the same height to insure even support, and utilize a hardened rubber, or any other suitable machinable material which will not enable the work piece to displace significantly downwardly upon the application of vacuum. The tops and bottoms, as a group, are selectively operable. The ability to periodically dress both ends of the interconnected supports gives the user the power to continually insure that each interconnected support set is within a more exacting vertical tolerance.

Abstract: The present invention provides a wafer carrier that includes an opening, which in one embodiment is a plurality of holes, disposed along the periphery of the wafer carrier. A gas emitted through the holes onto a peripheral back edge of the wafer assists in preventing the processing liquids and contaminants resulting therefrom from reaching the inner region of the base and the backside inner region of the wafer. In another embodiment, a plurality of concentric sealing members are used to prove a better seal, and the outer seal is preferably independently movable to allow cleaning of a peripheral backside of the wafer to occur while the wafer is still attached to the wafer carrier.

Abstract: A polishing tool used for a CMP process is disclosed. The polishing tool includes a polishing platen for holding a wafer faced-up thereon and carrying the wafer to move to and fro between a first position and a second position, a polishing pad for polishing the wafer, and a holder for holding the polishing pad to self-rotate and carrying the polishing pad to move across the wafer surface and further driving the polishing pad to polish the wafer.

Abstract: A carrier head for a chemical mechanical polishing apparatus includes a flexible membrane that applies a load to a substrate. A central portion of the flexible membrane is formed of a first material with a different rigidity than a second material that forms the annular portion of the flexible membrane.

Abstract: The present invention is a workpiece holder for polishing comprising at least a workpiece holder body having multiple perforated holes for holding a workpiece by vacuum adsorption and a back plate disposed on the back side of the body, which is provided with temperature controlling means or cooling means for the holder body. Thus, there is provided a workpiece holder for polishing, a polishing apparatus and a polishing method, which can provide a workpiece having good flatness by suppressing thermal deformation of the workpiece holder body and deformation of a resin film coated on the workpiece holding surface without degrading flatness of a workpiece held on the workpiece holder in the polishing of the workpiece, even when the number of polishing operation increases.

Abstract: Apparatus for processing a surface of a substrate includes a chamber containing a cavity that has one side that is open, the chamber wall including a lip surrounding the open side of the cavity. Gas ports, disposed within the chamber wall and opening through the lip, emit a pressurized gas so as to create a gas cushion between the lip and the surface when the open side of the cavity is placed adjacent to the surface, thus creating a seal between the cavity and an environment external to the chamber.

Abstract: A polishing method and polishing apparatus capable of improving the flatness of a wafer are provided. When a wafer is adhered to a wafer holding plate for polishing a surface to be polished of the wafer by pressing and rubbing the surface to be polished against a polishing pad on a polishing turn table, the wafer is held by vacuum-chucking the surface to be polished of the wafer such that a surface to be adhered of the wafer forms a convex surface in a vicinity including an arbitrary point in the surface to be adhered within a region surrounding a center of the surface to be adhered of the wafer, and the region being at least not less than 50% of an entire adhesion area; and the wafer is adhered to the wafer holding plate from a central portion of the surface to be adhered of the wafer.

Abstract: An invention is provided for a carrier head that includes a metal plate having an opening formed in a central location. The metal plate has a wafer side, which faces the backside of a wafer during a CMP operation, and a non-wafer side. Positioned above the non-wafer side of the metal plate, and located above the opening in the metal plate, is a bladder or membrane. To facilitate uniformity during polishing, an inflating pressure is applied to the bladder, or membrane, that is substantially equivalent to a polishing pressure utilized during the CMP operation. To facilitate transporting the wafer, a vacuum can be applied to the opening in the metal plate to adhere the wafer to the carrier head. Further, to release the wafer from the carrier head, the bladder, or membrane, can be inflated such that it protrudes through the opening in the metal plate.

Abstract: Disclosed is a device for grinding a liquid crystal display panel improving the efficiency of using equipment by independently operating first and second grinding units for grinding the unit liquid crystal display panel. The present invention includes a first grinding unit grinding edges of short or long sides of the unit liquid crystal display panel in a normal mode and a second grinding unit grinding the edges of the short or long sides of the unit liquid crystal display panel that are not ground by the first grinding unit in the normal mode or grinding the edges of the long and short sides of the unit liquid crystal display panel in an emergency mode.

Abstract: CMP systems and methods provide necessary vacuum and pressure to be applied from a vacuum chuck through a carrier film to a wafer without interfering with desired wafer planarization during CMP operations. Prior low polish rate-areas on the wafer may be eliminated from an exposed surface of the wafer by structure to uniformly compress the carrier film in response to a force from the wafer on the carrier film during the CMP operations. A distance between, and diameters of, adjacent holes of the carrier film are reduced, and the locations of the holes are in an array to coordinate with passageways through the vacuum chuck. The structure significantly reduces a maximum value of compression of the carrier film during CMP operations. As a result, during the CMP operations the wafer does not deform in a manner that exactly matches the compression of the carrier film, but remains essentially flat.

Abstract: A carrier with adjustable pressure zones and adjustable barriers between zones for distributing the pressure on the backside of a wafer. The pressure zones may be created using an elastic web diaphragm. One or more grooves are formed in the surface of the diaphragm to relieve vacuum formed between the diaphragm and wafer.

Abstract: The invention provides a chuck for holding a workpiece, such as a chip-array semiconductor Chip Scale Packages (CSP) substrate, having a plurality of components such as CSPs to be singulated, and chaff areas of the components. The chuck comprises means to hold the chaff areas when the components are being singulated, that may include a first pressure means to hold the components and a second pressure means to hold the chaff areas.

Abstract: Embodiments of the present invention are directed to a carrier head for positioning a substrate on a polishing surface. The carrier head includes a housing connectable to a drive shaft to rotate therewith; a base; a detachable plate removably mounted on top of the housing; a gimbal mechanism connecting the housing to the base to permit the base to move with respect to the housing such that the base remains substantially parallel to the polishing surface; and a flexible membrane defining a mounting surface for the substrate.

Abstract: A wafer carrier retaining ring includes a first annular surface that contacts a polishing surface during a polishing process and an inner diameter surface adjoining the first annular surface thereby forming a first annular corner. The first annular corner has a radius in the range of from no less than about 0.010 inches to less than a radius that would result in damage to a wafer being polished. In another embodiment of the invention, a wafer carrier retaining ring includes an inner diameter surface and a second annular surface adjoining said inner diameter surface thereby forming a second annular corner. The second annular corner has a radius of no less than 0.030 inches. In a further embodiment of the invention, a wafer carrier retaining ring is formed of a ceramic material and has a first annular surface having a surface finish of no greater than 2 microinches rms.

Abstract: A polishing apparatus comprises a carrier having a pressing surface to be engaged with a platy workpiece to press it against a polishing surface, whereby the workpiece is polished by being subjected to a relative sliding motion relative to the polishing surface while being pressed thereagainst. The pressing surface includes a suction opening provided along an outer peripheral portion of the pressing surface for applying a vacuum to hold the workpiece on the pressing surface during polishing of the workpiece. The carrier further comprises a pressure applying opening provided inside of the suction opening for applying a pressure to press the workpiece against the polishing surface during polishing of the workpiece.

Abstract: A semiconductor wafer handler comprises a ring (70) attached to a hub (80) by a plurality of spokes (90). Vacuum is applied to the surface of the semiconductor wafer through orifices (100) containing in the ring (70). Water and/or nitrogen can be applied to the surface of the semiconductor wafer through orifices (110) contained in the spokes (90).

Abstract: A plurality of spaced apart supports are designed to closely support a work piece immediately adjacent the edge being worked, ground or polished. Adjacent shear forced are also eliminated by the use of a polymeric interconnections used to both generally contribute to the spacing and to transmit the vacuum in a distributed manner among the individual support units. The top and bottom surfaces of the supports are dressably machineable in place on the working table to insure that all are brought to exactly the same height to insure even support, and utilize a hardened rubber, or any other suitable machinable material which will not enable the work piece to displace significantly downwardly upon the application of vacuum. The tops and bottoms, as a group, are selectively operable. The ability to periodically dress both ends of the interconnected supports gives the user the power to continually insure that each interconnected support set is within a more exacting vertical tolerance.

Abstract: The present invention uses some type of inflatable membrane during processing to establish a vacuum and/or provide a resilient cushion on which the backside of the wafer can rest. In one aspect, the present invention provides an outer vacuum that allow for attachment of the wafer to the carrier head during processing, and also provides an inner inflatable membrane that provides a resilient cushion on which the backside of the wafer can rest during processing. In other aspects, the present invention provides a membrane that is displaceable with a vacuum within certain cavity regions to provide for attachment of the wafer to the wafer carrier.

Abstract: A wafer polishing apparatus for polishing a semiconductor wafer. The polisher comprises a base, a turntable, a polishing pad and a head drive mechanism for driven rotation of a polishing head. The polishing head comprises a sealing ring adapted to hold at least one wafer for engaging a front surface of the wafer with a work surface of the polishing pad. The sealing ring allows for application of uniform air pressure over the rear surface of the wafer. The sealing ring is constructed so that the wafer itself defines a portion of a pressure cavity receiving pressurized air.

Abstract: The present invention provides a fixture for mounting a substrate to mounting tape on a film frame so as to retain the substrate to the film frame for dicing. A plurality of grooves for receiving a cutting saw extend longitudinally and transversely across the fixture to define die regions. The fixture also includes a plurality of apertures that align with the substrate and with dies to be cut from the substrate. The aligned apertures supply vacuum to the substrate to retain the substrate and cut dies in the fixture. When the dicing is completed, the vacuum is turned off and the individual dies can be readily removed from the fixture.

Abstract: The present invention provides a fixture for mounting a substrate to mounting tape on a film frame so as to retain the substrate to the film frame for dicing. A plurality of grooves for receiving a cutting saw extend longitudinally and transversely across the fixture to define die regions. The fixture also includes a plurality of apertures that align with the substrate and with dies to be cut from the substrate. The aligned apertures supply vacuum to the substrate to retain the substrate and cut dies in the fixture. When the dicing is completed, the vacuum is turned off and the individual dies can be readily removed from the fixture.

Abstract: A substrate holder is described which has a movable plate elastically mounted inside a main body. With the substrate holder, a polishing operation can be performed in two basic operation modes corresponding to two different vertical end positions of the movable plate. In a first (downward) mode the movable plate stays in mechanical contact with the substrate whereas in a second (upward) mode an air cushion is generated in a chamber between the movable plate and the substrate for pressurizing the substrate onto the polishing pad.

Abstract: In the wafer abrasive machine of the present invention, a gravity center and a rotational axis of a wafer can be corresponded while abrading the wafer and a holding plate can be smoothly moved in a head member. The abrasive machine comprises: the head member including a concave section, in which the holding plate is accommodated; an elastic sheet member suspending the holding plate and being reinforced by a cloth-formed reinforcing member; a space for storing pressure fluid which pushes the holding plate toward the abrasive plate, the space being formed between the elastic sheet member and the concave section; and a plurality of spherical bodies being provided between an outer circumferential face of the holding plate and an inner circumferential face of the concave section, the spherical bodies simultaneously point-contact the both circumferential faces.

Abstract: The invention relates, in one embodiment, to an arrangement configured to support a substrate during a dicing process. The substrate has thereon a first substrate side and a second substrate side. The first substrate side is smoother than the second substrate side. The arrangement includes a nest having a first nest side and a second nest side. The nest includes a grid which defines at least one nest opening. The nest opening has an opening area that is smaller than an area of a die diced from the substrate. The arrangement further includes a vacuum retainer plate having thereon at least one vacuum pedestal. The vacuum pedestal has an upper surface formed of a resilient material. The vacuum pedestal is configured to be disposed through the nest opening when the nest is mated with the vacuum retainer plate.

Abstract: A chuck means for flat workpieces, in particular semi-conductor wafer for the chemical-mechanical polishing, comprising a circular housing which is attached to a driving spindle for rotation therewith and has a top wall and an annular side wall, a retaining ring which forms the lower part of the side wall, a chuck plate of rigid, however elastically deformable material which has an upper and a lower side and a plurality of openings at the lower side as well which openings are in connection with radial and axial parallel passages in the chuck plate, the passages being in fluid connection with an axial passage in the spindle, the axial passage being connected to a vacuum and/or fluid source, the chuck plate being floatingly and vertically movably located in the housing, a plurality of pressure chambers above the chuck plate, the pressure chambers having lower wall portions which are yieldable and engage the upper side of the chuck plate, pressure manifold means which are connected with a fluid source under pres

Abstract: A wafer carrier head assembly for holding a wafer in chemical mechanical planarization applications is dis;losed that includes a downwardly protruding wafer retaining ring that moves independent of the wafer carrier head and retains an edge of the wafer on said polishing surface. An adjustable wafer holding mechanism that applies one of a uniform downward force and a uniform upward force to the wafer is also included. Application of the upward force allows the wafer holding mechanism to retain and transport the wafer to a polishing surface. Application of the downward force allows the wafer holding mechanism to retain the wafer on the polishing surface and allows the wafer to be uniformly polished. The wafer carrier head assembly herein disclosed is also configured to pivotally accommodate changes in parallelism between the wafer and the polishing surface when the wafer is being polished.

Abstract: There is provided a vacuum chuck apparatus which eliminates the need to stop machining of a workpiece for cleaning of a filter of the vacuum chuck apparatus and thus enables a long-term continuous operation of a machine tool.

Abstract: Generally, a method and apparatus for retaining a substrate is provided. In one embodiment, a carrier for retaining a substrate comprises a carrier plate having a lower surface, at least one first fluid outlet and a second fluid outlet. The first fluid outlet is fluidly coupled to the lower surface of the carrier plate. The second fluid outlet is fluidly coupled to the lower surface of the carrier plate. A first fluid circuit is coupled to the first fluid outlet and is adapted to flow a fluid forms a fluidic layer between the carrier plate and the substrate. A second fluid circuit is coupled to the second fluid outlet and is separate from the first fluid circuit.

Abstract: The present invention has an object to provide a retention plate used in a polishing device that mirror polishes semiconductor substrates such as silicon wafers, particularly a retention plate used with the hard chuck method, that can prevent roll-off, and can achieve a high improvement in flatness. According to the present invention, by means of using a retention plate of a constitution that is of a smaller diameter than that of the wafer and which gives a region in which the area of contact with the wafer is reduced by means of groove processing, or a porous structure and the like, on the outer peripheral part, a reduction of the processing pressure of the outer peripheral part becomes possible, and, because the polishing of the region in which roll-off occurs is delayed, the amount removed by polishing becomes uniform over the wafer surface, and high precision wafer processing becomes possible.