Fixture and method for determining position of a target in a reaction chamber

A method of determining position of a target within a reaction chamber of a semiconductor processing system, comprising:

• at a fixture including a fixed above a reaction chamber, a leveling plate supported on the frame, a bracket supported on the leveling plate, and a laser profiler suspended from the bracket and overlaying the reaction chamber, the laser profiler having a field of view extending through the leveling plate and the frame,
• leveling the leveling plate above the reaction chamber relative to gravity;
• projecting a line into the reaction chamber and onto a target within the reaction chamber;
• acquiring height of the laser profiler above the target at a first point and a second point along the line, the second point spaced apart from the first point along the line;
• and
• determining position of the target using height of the laser profiler above the target at the first point and the second point along the line.