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

A susceptor for efficiently heating a wafer within a CVD environment and effectively isolating a heating element of the susceptor from the CVD environment comprising:

• a partially hollow susceptor body mounted on a support shaft and containing the heating element;
• a planar member mounted on the susceptor body and coupled to the heating element, the planar member having a surface for supporting and heating a wafer;
• the interface between the susceptor body and the support shaft and the interface between the susceptor body and planar member each being sealed to create a generally vacuum-tight first space within the susceptor body which surrounds the heating element and effectively protects the heating element from exposure to the CVD environment;
• a gas delivery tube extending through the susceptor body and first space to deliver backside heating gas to a wafer placed on said planar member surface;
• a sheath surrounding a portion of said tube and creating a second space between the tube and sheath, one end of the sheath coupled to an opening in the planar member to direct the backside heating gas from the tube to the wafer, the sheath sealed to the planar member at the end coupled to the opening and sealed to the tube at the other end such that the second space is effectively isolated from the first space so that backside heating gas may be delivered to the wafer to facilitate more efficient heat transfer from the heating element while the heating element remains protected from the corrosive chemical vapors of the CVD environment.

A method for efficiently heating, with a heating element, a wafer within a CVD reaction space evacuated to a process pressure while effectively isolating the heating element from the CVD environment comprising:

• placing a wafer on a surface of a susceptor, the susceptor having a space therein for housing a heating element coupled to the surface to heat the surface and the wafer;
• sealing the susceptor space with respect to the CVD reaction space to effectively isolate the heating element from the CVD environment;
• directing backside heating gas into a space extending through the susceptor space and through an opening in the susceptor surface such that the gas contacts a wafer on said surface and facilitates efficient heat transfer between the wafer and the heated surface;
• and
• sealing the gas directing space with respect to the susceptor space to prevent exposure of the heating element to the gas directing space and to further effectively isolate the heating element from the CVD environment;
• whereby the wafer if efficiently heated while the heating element is protected from corrosive chemical vapors existing in the CVD environment.

A method of depositing a layer of material on a semiconductor wafer by chemical vapor deposition (CVD) including the step of heating the wafer, the method comprising:

• placing a wafer on a surface of a susceptor, the susceptor having a space therein for housing a heating element coupled to the surface to heat the surface and the wafer;
• sealing the susceptor space with respect to the CVD reaction space to effectively isolate the heating element from the CVD environment;
• directing backside heating gas into a space extending through the susceptor space and through an opening in the susceptor surface such that the gas contacts a wafer on said surface and facilitates efficient heat transfer between the wafer and the heated surface;
• and
• sealing the gas directing space with respect to the susceptor space to prevent exposure of the heating element to the CVD reaction space and to further effectively isolate the heating element from the CVD environment;
• introducing CVD reactant gases in the proximity of the wafer to react and deposit a material layer on the heated wafer;
• whereby a material layer is deposited on a heated wafer while the heating element is protected from corrosive effects of the CVD reactant gases contributing to the material layer.