Ultra pure N₂ and gas heaters for reducing by-product deposition in wafer processing equipment.

During the manufacture of semiconductor components, such as integrated circuits, memory chips, and the like, the failure of valves and pumps used in connection with wafer processing equipment is problematic. The failure is often caused by the deposition of by-products, such as by deposition of ammonium chloride (NH₄Cl). In certain chemical vapor deposition ("CVD") processes such as chloride-based ammonium reduction CVD processes, ammonia chloride (NH₄Cl) is formed by reacting, for example, hydrogen chloride (HCL) with ammonia (NH₃). The resulting ammonia chloride may sublimate to a solid and stick to the inside of a wafer processing chamber wall or on the inside of associated valves and pumps. The build up over time of solidified ammonium chloride inside the valves and pumps may cause the valves to leak and the pumps to degrade, and the solidified ammonium chloride may also be transmitted into the process chambers, contaminating the manufacturing processes and reducing their yield.

One attempt at solving such a problem involves placing heaters around the wafer processing chamber or associated pump or conduits to maintain the produced ammonium chloride in a gaseous form to prevent sublimation to a solid form but this is not very effective due to following reason: However, in single wafer processing reactors for chemical vapor deposition of silicon nitride (SiC₄H₂ and NH₃ reaction) and titanium nitride (TiCl₄ and N₄ reaction), process gases from a shower head flow into and through a chamber with high velocity and low temperatures. This flow removes a large amount of heat from inner walls of the reaction system. Because of the removal of heat from the inner walls, heating the outer walls may not be sufficient to prevent sublimation of ammonium chloride to a solid form. Providing a heated gas; and introducing heated gas into the chamber concurrently with a step of introducing a plurality of reactant gases into the chamber to maintain the peripheral inner wall at a temperature sufficiently high to maintain reaction product in the gaseous phase of sublimation curve when contacting the peripheral inner wall.