METHOD AND APPARATUS FOR CONTROLLING PLASMA UNIFORMITY

摘要

Systems, methods, and apparatus involve a plasma processing chamber (200, 200', 200'') for depositing a film (231) on a substrate (232). The plasma processing chamber (200) includes a lid assembly (214) having a ground plate (225), a backing plate (240), and a non-uniformity (201) existing between the ground plate (225) and the backing plate (240). The non-uniformity (201) may interfere with RF wave uniformity and cause an impedance imbalance between portions of the ground plate (225) and backing plate (240). The non-uniformity (201) may include a structure (300) or a reduced spacing (400) of non-uniform surfaces. A reduced spacing (400) of non-uniform surfaces may exist where a first distance (d1, d2) between the ground plate (225) and the backing plate (240) at a first end (402) is different from a second distance (d3) between the ground plate (225) and the backing plate (240) at a second end (404). The structure (300) may be from 2cm to 10cm thick, cover from 20% to 50% of the backing plate (240), and be located away from a discontinuity (207) existing inside the chamber (200').