Chemical mechanical polishing apparatus and method having a retaining ring with a contoured surface for slurry distribution

A polishing head for positioning a surface of a substrate against a polishing surface, the polishing head comprising:

• a subcarrier adapted to hold the substrate during a polishing operation;
• a retaining ring having an outer edge and 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 grooves formed therein to distribute a polishing liquid between the substrate held on the subcarrier and the polishing surface when there is relative motion between the substrate and the polishing surface;
• and
• wherein said number of radial grooves comprises an angle between the outer and the inner edge of the retaining ring and the directions of each of the number of radial grooves at the inner edge and the outer edge of the retaining ring are oriented in a same direction with respect to a direction of a rotation of the retaining ring,
• whereby non-planar polishing of the surface of the substrate is inhibited.

A polishing head for positioning a surface of a substrate against a polishing surface, the polishing head comprising:

• a subcarrier adapted to hold the substrate during a polishing operation:
• and
• a retaining ring having an outer edge and 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 grooves formed therein to distribute a polishing liquid between the substrate held on the subcarrier and the polishing surface when there is relative motion between the substrate and the polishing surface,
• wherein each of said number of radial grooves comprise a chevron shape having an apex between the outer and the inner edge of the retaining ring whereby a polishing liquid accumulates about said apex.

A method of polishing a substrate having a surface using a polishing apparatus comprising a polishing surface, a polishing head having a subcarrier 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 plurality of radial recesses formed therein, the method comprising steps of:

• positioning the substrate on the subcarrier;
• pressing the surface of the substrate and the lower surface of the retaining ring against the polishing surface;
• dispensing a chemical onto the polishing surface;
• providing relative motion between the polishing head and the polishing surface;
• and
• distributing the chemical between the substrate held on the subcarrier and the polishing surface through the plurality of radial recesses.