Present disclosure provides chemical mechanical polishing (CMP) apparatus, including a counterface configured to support a semiconductor wafer at a first surface, a first electromagnet array under the first surface, a polishing head over the counterface and configured to hold the semiconductor wafer at a second surface, and a controller connects to the first electromagnet array. The first electromagnet array comprises a plurality of electromagnets, a polarity of each of the plurality of electromagnets is capable of being individually controlled by the controller. Present disclosure also provides a CMP slurry and a method for using a chemical mechanical polishing apparatus.

This invention relates to a method for feeding magnetic objects in a stream which are singulated each from the next in a supply path where there is provided a series of electromagnets which provides a sequence of magnetic fields along the supply path to direct the magnetic objects by the series of electromagnets in a required direction toward a required location. The method can be used for carrying out an operation on a workpiece by interaction of the objects as individual tools with the workpiece including sorting, shaping, material removal, physical modification, chemical modification, addition of material cutting, polishing, abrading peening and addition of energy. A lubricant/purge material is supplied to the workpiece to arrive at different times relative to the tools.

Provided is a self-sharpening polishing device with magnetorheological flexible polishing pad formed by dynamic magnetic field and polishing method thereof. The device includes a polishing disc revolution mechanism and a multi-magnetic-pole synchronous rotary drive mechanism, the polishing disc revolution mechanism including a transmission shaft motor, a transmission shaft, a transfer disc, an eccentric shaft fixing disc, a cup-shaped polishing disc and a transmission shaft transmission mechanism, the multi-magnetic-pole synchronous rotary drive mechanism including an eccentric spindle, a synchronous rotary drive disc, flexible eccentric rotating shafts, eccentric sleeves, magnetic poles, the eccentric shaft fixing disc, and a spindle motor, etc. The device does not need a circulating device to renew magnetorheological fluid and does not need to renew the magnetorheological fluid during the finishing process; in fact the entire process from rough polishing to precise polishing can be done at one time. The device maintains a consistent workpiece surface and delivers a low cost and very efficient polishing process that is eminently suitable for the planes of optical elements with large diameter; it is also suitable for studying the material removal mechanism of planar optical materials and detecting sub-surface damage, as well as other experimental studies.

Various examples are provided for polishing techniques for flexible tubular workpieces. In one example, a method includes supporting a tubular workpiece on a rod that extends axially through it; positioning a turning wheel against an external surface of the tubular workpiece, where it is held by magnetic attraction; and rotating the tubular workpiece by rotating the turning wheel. The external surface of the tubular workpiece is polished by the abrasive particles during rotation of the tubular workpiece. In another example, a polishing system includes a workpiece holder including a rod configured to axially support a tubular workpiece; a turning wheel with abrasive particles distributed about an outer surface; a wheel support assembly configured to position the outer surface of the turning wheel against the an external surface of the tubular workpiece, where it is held by magnetic attraction. The external surface is polished during rotation of the tubular workpiece.

A magnetic-disk glass substrate containing an alkali metal component as a glass composition includes a pair of main surfaces and an outer circumferential side edge surface that is a mirror surface. The outer circumferential side edge surface includes a surface with a roughness percentage that is 40% or more when a bearing ratio of a roughness cross-sectional area is 50%, in a bearing ratio curve of roughness cross-sectional areas obtained when a surface roughness of the outer circumferential side edge surface obtained by etching the outer circumferential side edge surface by 2.5 m is measured.

A magnetic field-assisted vibratory finishing device for a minute structure and a finishing method is provided. The device includes a rotating shaft, a workpiece clamping device, a magnetic field generating device, a vibration assisting device, a three-axis precision displacement platform and a base. The magnetic field generating device includes a baffle plate, magnetic bars and a magnetic-pole groove. The vibration assisting device includes a housing, guide fixing rods, a vibration motor, a vibration connecting plate, and compression springs. The workpiece clamping device clamps parts with a variety of structural shapes, and a frequency controller can control the motion mode of the magnetic field generating device during the finishing processing, thereby controlling the motion track of grinding material.

An edge surface of a magnetic-disk glass substrate containing an alkali metal component as a glass composition is a mirror surface, and in a bearing ratio curve of roughness cross-sectional areas obtained by measuring a surface roughness of the edge surface obtained by etching the edge surface by 2.5 m, a roughness percentage when a bearing ratio of a roughness cross-sectional area is 50% is 40% or more.

Various examples are provided for hybrid tools including fixed-abrasive and loose- abrasive phases. In one example, a hybrid tool for finishing an internal surface of a workpiece includes a metallic rod and magnetic abrasive bonded to one or more defined portions of the metallic rod by an adhesive that dissolves when n contact with a lubricant used to finish the internal surface of the workpiece. In another example, a method for finishing an internal surface of a workpiece includes mounting the workpiece in a chuck of a lathe; positioning a hybrid tool inside an internal cavity of the workpiece using one or more pole-tips; providing an amount of the lubricant to the internal cavity; and rotating the workpiece with the lathe while controlling positioning of the hybrid tool inside the internal cavity using the one or more pole-types.

The disclosure relates to a permanent magnet-electromagnet hybrid array type magnetorheological polishing device, comprising a polishing mechanism, a main excitation device arranged on the polishing mechanism, and auxiliary permanent magnet sets used for driving magnetorheological liquid to be recycled. The main excitation device is a permanent magnet-electromagnet hybrid array comprising main excitation permanent magnets and fine-adjustment electromagnetic excitation devices connected with the main excitation permanent magnets. Each fine-adjustment electromagnetic excitation device comprises a coil and a coil retaining pile. The main excitation device further comprises a permanent magnet-electromagnet device connecting plate made from a non-magnetically conductive material. The disclosure can improve magnetorheological polishing efficiency, reduce the size of the excitation device, and balance and control the thickness of a ribbon array, thus realizing high-accuracy and high-quality machining of the surfaces of elements and recycling of magnetorheological liquid.

Provided is a self-sharpening polishing device with magnetorheological flexible polishing pad formed by dynamic magnetic field and polishing method thereof. The device includes a polishing disc revolution mechanism and a multi-magnetic-pole synchronous rotary drive mechanism, the polishing disc revolution mechanism including a transmission shaft motor, a transmission shaft, a transfer disc, an eccentric shaft fixing disc, a cup-shaped polishing disc and a transmission shaft transmission mechanism, the multi-magnetic-pole synchronous rotary drive mechanism including an eccentric spindle, a synchronous rotary drive disc, flexible eccentric rotating shafts, eccentric sleeves, magnetic poles, the eccentric shaft fixing disc, and a spindle motor, etc. The device does not need a circulating device to renew magnetorheological fluid and does not need to renew the magnetorheological fluid during the finishing process; in fact the entire process from rough polishing to precise polishing can be done at one time. The device maintains a consistent workpiece surface and delivers a low cost and very efficient polishing process that is eminently suitable for the planes of optical elements with large diameter; it is also suitable for studying the material removal mechanism of planar optical materials and detecting sub-surface damage, as well as other experimental studies.