Patent ID: 6107198
Filing Date: 2000-08-22
Classification: C23C,Y10S

Abstract:
A method for depleting a condensed by-product held in an exhaust circuit of a low pressure chemical vapor deposition apparatus, said condensed by-product is generated in a vapor phase by a chemical reaction between a source material and a semiconductor substrate in a reactor of said low pressure chemical vapor deposition apparatus, the handling and depletion of said condensed by-product comprises the steps of:placing a semiconductor substrate on a support in a process reactor for forming a protective layer thereon;introducing at least one source material to the process reactor through a source material introducing means;forming a protective layer on the semiconductor substrate from said at least one source material;evacuating said condensed by-product generated by said chemical reaction in said process reactor;providing a first path means and a second path means, in said exhaust circuit, for evacuating said condensed by-product, said first path means includes a temperature controlled sublimation trap for condensing and storing a condensed by-product and preventing said condensed by-product from backstreaming and damaging a first path vacuum pump; said second path means is disposed parallel to said first path means, said second path means includes an isolation valve, a cold trap, and an auxiliary vacuum pump;providing a two-stage valve for isolating said first and second path means from the process reactor after completion of the low pressure chemical vapor deposition process;providing a second isolation valve means disposed at an inlet of said first path vacuum pump for isolating said first path vacuum pump from said sublimation trap during a heating of condensed by-product solids held in said sublimation trap;providing a cold trap isolation valve means disposed at an inlet of said cold trap for isolating an outlet of said sublimation trap from said cold trap during a nitride growth process.