Patent ID: 9076826
Filing Date: 2015-07-07
Classification: H01L

Abstract:
1. 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: an upper ring having 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 upper 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 central section; a plurality of hanger caps located in the upper sections of the hanger bores, each 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; a plurality of hangers located in the lower sections of the hanger bores with an upper end of each hanger fitted in one of the hanger caps such that the helical spring is compressed, the hangers movable vertically with respect to the hanger caps and rotatable to lock positions, each of the hangers including at least one projection adapted to rotate in the hanger cap to engage a seat in the hanger cap, each hanger including a lower section having an enlarged lower end; a lower ring having 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, each of the hangers having a lower section thereof received in one of the through bores, the lower ring having inner and outer diameters equal to inner and outer diameters of the upper ring and a uniform thickness of about 0.090 to 0.1 inch; and a plurality of spacer sleeves each of which includes an upper wall, a lower wall, an outer wall, an inner wall and a through hole extending between the upper and lower walls, each of the spacer sleeves located in the lower section of a respective one of the hanger bores, each of the hangers extending through one of the respective through holes; wherein the outer wall of the hanger cap is separated from an inner wall of the upper section of the hanger bore by at least 0.01 inch, the spacer sleeve is spaced from an inner wall of the lower section of the hanger bore by at least 0.1 inch, and the outer surface of the hanger is spaced from the inner wall of the smaller diameter section of the hanger bore by at least 0.1.