Heated metal lid for selective pecvd

A gas distribution assembly for a semiconductor manufacturing processing chamber comprising:

• a first showerhead connected to a backing plate, the backing plate having a first flange defining an outer edge, the first flange having a first portion extending orthogonally from a back surface of the backing plate and a second portion extending orthogonally outward from the first portion;
• a second showerhead spaced from the first showerhead, the second showerhead having a second flange having a first portion extending along a plane of the second showerhead, a second portion extending orthogonally from a back of the first portion and a third portion extending orthogonally outward from the second portion;
• a first two-piece RF isolator comprising a first inner RF isolator and a first outer RF isolator, the first inner RF isolator spaced a distance from the first outer RF isolator to create a first portion of a first flow path and the first inner RF isolator spaced from the first flange of the first showerhead to create a second portion of the first flow path;
• and
• a second two-piece RF isolator comprising a second inner RF isolator and a second outer RF isolator, the second inner RF isolator spaced a distance from the second outer RF isolator to create a first portion of a second flow path and the second inner RF isolator spaced from the second flange of the second showerhead to create a second portion of the second flow path.