Combined thermal and plasma assisted atomic layer deposition

A method of etching a substrate surface, the method comprising:

• exposing the substrate surface to an inductively coupled plasma (ICP), the ICP comprising helium (He);
• and
• applying a bias voltage to the substrate surface,
• the ICP being generated at least in part by a plasma coil assembly comprising:
• a ring-shaped body having an inner wall with an inside face and an outside face, a bottom wall with an inside face and an outside face, and an outer wall with an inside face and an outside face, the ring-shaped body having an open top portion;
• an RF electrode positioned within the open top portion of the ring-shaped body, the RF electrode having a first end and a second end defining a length of the RF electrode, a thickness and a width, the RF electrode formed in a coil having at least two spaced revolutions with the first end spaced a distance from the outer wall of the ring-shaped body and the second end spaced a distance from the inner wall of the ring-shaped body, the first end closer to a lowest point of the outside face of the bottom wall than the second end;
• a first RF electrode connection in electrical contact with the first end of the RF electrode;
• a second RF electrode connection in electrical contact with the second end of the RF electrode;
• and
• a dielectric top plate positioned within the open top portion of the ring-shaped body.