Apparatus for liquid treatment of wafer shaped articles and liquid control ring for use in same

Apparatus for treating a wafer-shaped article, comprising:

• a rotary chuck configured to hold a wafer-shaped article of a predetermined diameter such that a surface of the wafer-shaped article facing said rotary chuck is spaced from an upper surface of the rotary chuck;
• and
• a ring mounted on the rotary chuck, said ring comprising a first upper surface overlapping an outer peripheral edge of a wafer-shaped article when positioned on the rotary chuck and a second upper surface positioned radially inwardly of said first surface;
• wherein said second upper surface is elevated relative to said first upper surface, to define an annular gap between said second upper surface and a wafer-shaped article when positioned on the spin chuck that is smaller than a distance between said first upper surface and a wafer-shaped article when positioned on the rotary chuck;
• and
• wherein said ring comprises a lower surface that is spaced from a body of the rotary chuck.