Plasma confinement ring assembly for plasma processing chambers

An upper ring of a plasma confinement ring assembly useful for controlling wafer area pressure in a capacitively coupled plasma reaction chamber wherein a wafer is supported on a lower electrode assembly and process gas is introduced into the chamber by an upper showerhead electrode assembly, wherein:

• the upper ring has an upper wall, a lower wall, an outer wall, an inner wall, a series of circumferentially extending slots which pass through the upper and lower walls, a plurality of twist and lock bores in the upper wall adapted to engage with vertically movable plungers mounted in a top wall of the plasma reaction chamber such that the upper ring is supported by the plungers by inserting free ends of the plungers in the twist and lock bores and rotating the plasma confinement ring to lock the plungers in narrow ends of the twist and lock bores, a plurality of hanger bores extending between the upper and lower walls, the hanger bores including larger upper and lower sections connected by a smaller diameter central section.

A hanger assembly of a plasma confinement ring assembly useful for controlling wafer area pressure in a capacitively coupled plasma reaction chamber wherein a wafer is supported on a lower electrode assembly and process gas is introduced into the chamber by an upper showerhead electrode assembly, comprising:

• a hanger cap configured to fit in an upper sections of a hanger bore in an upper ring of the plasma confinement ring assembly, the hanger cap including a stepped bore in a lower wall thereof and a helical spring press fitted in a small diameter upper section of the stepped bore;
• and
• a hanger configured to fit in a lower section of the hanger bore in the upper ring of the plasma confinement ring assembly, the hanger having an upper end configured to fit in the stepped bore of the hanger cap such that the helical spring is compressed, the hanger being movable vertically with respect to the hanger cap and rotatable to a lock position, the hanger including at least one projection adapted to rotate in the stepped bore of the hanger cap to engage a seat in the hanger cap, and the hanger including a lower section having an enlarged lower end.

A lower ring of a plasma confinement ring assembly useful for controlling wafer area pressure in a capacitively coupled plasma reaction chamber wherein a wafer is supported on a lower electrode assembly and process gas is introduced into the chamber by an upper showerhead electrode assembly, wherein:

• the lower ring has an upper wall, a lower wall, an outer wall, an inner wall and a plurality of through bores extending through the upper and lower walls, the through bores sized to receive hangers of the plasma confinement ring assembly with enlarged heads on the bottoms of the hangers below the lower wall of the lower ring, the lower ring having inner and outer diameters equal to inner and outer diameters of an upper ring of the plasma confinement ring and the lower ring having a uniform thickness of about 0.090 inch.

A middle ring of a plasma confinement ring assembly useful for controlling wafer area pressure in a capacitively coupled plasma reaction chamber wherein a wafer is supported on a lower electrode assembly and process gas is introduced into the chamber by an upper showerhead electrode assembly, wherein:

• the middle ring has a thickness of about 0.27 inch, an inner diameter of about 17 inches and an outer diameter of about 20 inches, three hanger receiving keyhole shaped holes each of which has a diameter of about 0.42 inch located on a radius of about 8.5 inches and a slot extending radially inward therefrom with a width of about 0.175 inch, three seats in a lower surface of the middle ring each of which extends radially outward from each of the keyhole shaped holes, each of the seats having a width of about 0.23 inch and depth of about 0.15 to 0.2 inch, a heat choke comprising thirty six inner slots and thirty six outer slots, the inner slots being located on a radius of about 8.8 inches and the outer slots being located on a radius of about 9 inches, each of the slots extending circumferentially about 16.5° with ends of the slots spaced about 3.5° apart, and at least one end of each slot terminating in a circular hole having a radius of about 0.015 inch.