Method for isolating a susceptor heating element from a chemical vapor deposition environment

摘要

An apparatus for efficiently heating a wafer within a CVD environment isolates the heating element of the apparatus from the CVD environment and includes a susceptor body defining a sealed space therein for containing the heating element and a surface coupled to the heating element for supporting and heating the wafer. The susceptor space is sealed from the CVD environment and is vacuumed to a first pressure. Heating gas is delivered through a space extending through the susceptor body which is sealed from the susceptor space containing the heating element and is vacuumed to a second pressure which is preferably less than the CVD reaction pressure to vacuum clamp a wafer to the susceptor. The heating gas delivery space is formed by an elongated sheath surrounding a hollow wafer lift tube and the sheath is sealed at one end to the backplane of the susceptor and at the other end to the tube. The wafer lift tube moves up and down within the sheath to lift a wafer. Various unique seals provide isolation of the heating element space and gas delivery space from each other and from the CVD reaction environment to protect the heating element from the corrosive effects of CVD vapors.