| abstract |
A shower plate is adapted to be attached to the showerhead and includes a front surface adapted to face the susceptor; and a rear surface opposite to the front surface. The shower plate has multiple apertures each extending from the rear surface to the front surface for passing gas therethrough in this direction, and the shower plate has at least one quadrant section defined by radii, wherein the one quadrant section has an opening ratio of a total volume of openings of all the apertures distributed in the section to a total volume of the one quadrant section, which opening ratio is substantially smaller than an opening ratio of another quadrant section of the shower plate. |