Polishing compositions comprising ceria coated silica particles and organic acids having one selected from the group consisting of sulfonic acid group, phosphonic acid group, pyridine compound, and combinations thereof, with pH between 5 and 10 and electrical conductivity between 0.2 and 10 millisiemens per centimeter provide very high silicon oxide removal rates for advanced semiconductor device manufacturing.

Polishing compositions comprising ceria coated silica particles and organic acids having one selected from the group consisting of sulfonic acid group, phosphonic acid group, pyridine compound, and combinations thereof, with pH between 5 and 10 and electrical conductivity between 0.2 and 10 millisiemens per centimeter provide very high silicon oxide removal rates for advanced semiconductor device manufacturing.

A workpiece has a device area and a peripheral area surrounding the device area on a front surface side thereof. A workpiece grinding method includes a groove forming step of performing grinding feed of a grinding unit while a spindle is rotated, and grinding a predetermined area on a back surface side of the workpiece, the predetermined area corresponding to the device area, in a state in which a chuck table holding the workpiece is not rotated, thereby forming a groove on the back surface side, a groove removing step of starting rotation of the chuck table while the spindle is kept rotating, thereby grinding side walls of the groove and removing the groove, and a recess forming step of performing grinding feed of the grinding unit while the spindle and the chuck table are rotated, thereby grinding the predetermined area and forming a recess and a ring-shaped reinforcement part.

A workpiece has a device area and a peripheral area surrounding the device area on a front surface side thereof. A workpiece grinding method includes a groove forming step of performing grinding feed of a grinding unit while a spindle is rotated, and grinding a predetermined area on a back surface side of the workpiece, the predetermined area corresponding to the device area, in a state in which a chuck table holding the workpiece is not rotated, thereby forming a groove on the back surface side, a groove removing step of starting rotation of the chuck table while the spindle is kept rotating, thereby grinding side walls of the groove and removing the groove, and a recess forming step of performing grinding feed of the grinding unit while the spindle and the chuck table are rotated, thereby grinding the predetermined area and forming a recess and a ring-shaped reinforcement part.

A polishing brush (1) includes a rod-shaped member (2) and a grinding element bundle (4) formed of a plurality of wire-shaped grinding elements (3). The rod-shaped member (2) has a holding hole (6) at a front portion (2a) to hold the grinding element bundle (4). The holding hole (6) has a bottom face (7) and a sleeve-shaped peripheral wall (8) extending from the bottom face (7) in an inclination direction (S). The grinding element bundle (4) has a seated portion (4a) seated in the holding hole (6) and a protruding portion (4b) protruding from an opening (6a) of the holding hole (6) in the inclination direction (S). The tip end of the protruding portion (4b) is located on the outside of the rod-shaped member (2) when viewed from the axis (L0) direction.

A polishing brush (1) includes a rod-shaped member (2) and a grinding element bundle (4) formed of a plurality of wire-shaped grinding elements (3). The rod-shaped member (2) has a holding hole (6) at a front portion (2a) to hold the grinding element bundle (4). The holding hole (6) has a bottom face (7) and a sleeve-shaped peripheral wall (8) extending from the bottom face (7) in an inclination direction (S). The grinding element bundle (4) has a seated portion (4a) seated in the holding hole (6) and a protruding portion (4b) protruding from an opening (6a) of the holding hole (6) in the inclination direction (S). The tip end of the protruding portion (4b) is located on the outside of the rod-shaped member (2) when viewed from the axis (L0) direction.

A surface finishing apparatus and method for smoothing and coloring parts made by additive-manufacturing technologies is disclosed. The surface finishing apparatus includes a tank or chamber into which a part is placed. A colorant is added. The part is both colored and smoothed until the part is at a desired smoothness and color. The part may be smoothed by different suitable smoothing technologies, including abrading with solid media, spraying with a liquid fluid, spraying with solid particles entrained in a liquid fluid, or submersing in a liquid vortex. Also disclosed is a composition for a colorant for a finishing process that smooths a surface of an additively manufactured part while coloring the additively manufactured part.

A surface finishing apparatus and method for smoothing and coloring parts made by additive-manufacturing technologies is disclosed. The surface finishing apparatus includes a tank or chamber into which a part is placed. A colorant is added. The part is both colored and smoothed until the part is at a desired smoothness and color. The part may be smoothed by different suitable smoothing technologies, including abrading with solid media, spraying with a liquid fluid, spraying with solid particles entrained in a liquid fluid, or submersing in a liquid vortex. Also disclosed is a composition for a colorant for a finishing process that smooths a surface of an additively manufactured part while coloring the additively manufactured part.

Letting a particle diameter be Dx (μm) when a cumulative particle volume cumulated from the small particle diameter side reaches x (%) of the total particle volume in a particle size distribution obtained regarding cerium oxide included in a polishing liquid using a laser diffraction/scattering method, D5 is 1 μm or less, and a difference between D95 and D5 is 3 μm or more.

A mid-frequency error-free machining method under a magneto-rheological polishing magic angle-step includes the following steps: measuring a magneto-rheological removal function, and determining a control accuracy of a machine tool; performing two-dimensional Fourier transform on the removal function, performing compensating filtering on a frequency spectrum based on the control accuracy of the machine tool, and analyzing a corresponding step at the lowest point of an amplitude of the two-dimensional frequency spectrum that undergoes filtering in a direction of a magic angle; planning a grid path under the given step on the basis of adjusting a direction of a machining path or a posture of a magneto-rheological polishing wheel to allow an included angle between the polishing wheel and the path kept to be at the magic angle; and finally, controlling the machining of the machine tool.