Abstract: A method comprises arranging an apparatus on a top surface of a pedestal in a processing chamber. The apparatus comprises an annular member, N supporting members, and N pins, where N is an integer greater than two. The N supporting members support the annular member in a plane parallel to and above the top surface of the pedestal. The N pins are arranged perpendicularly to the plane along a circumference around the annular member. Each of the N pins includes threads engageable with respective threaded slots in the apparatus. Each of the N pins includes a conical end pointing towards the top surface of the pedestal and engageable with a periphery of the top surface of the pedestal. The method further comprises aligning a center of the annular member to a center of the pedestal by adjusting one or more of the N pins.