Susceptor hold-down mechanism

Abstract

A structure and method for holding a susceptor in a single-wafer RF heated CVD reactor allows the center portion of the susceptor to be heated and prevents susceptor and reactor damage due to overdriving and the susceptor from losing contact with a rotatable rod during thermal expansion. A plug, located on the bottom surface of the susceptor, heated by RF energy subsequently heats the center portion of the susceptor, thereby providing constant temperature gradients across the susceptor. The plug is connected to a rod which is contained in an upper tube and extends into a lower tube. The upper tube is connected to the susceptor via a locking mechanism. An upper spring in the upper tube applies a downward force on the upper tube such that an upward force on the bottom of the susceptor compresses the upper spring, thereby relieving stress on the susceptor and preventing damage due to overdriving. A lower spring is provided within a lower tube connected to the rod such that the lower spring forces the rod upward to keep continual contact with the plug during various times of thermal expansion. The two springs also allow easy removal and assembly of the susceptor and rod structure for cleaning and repair.