Patent ID: 6561226
Filing Date: 2003-05-13
Classification: C23C,Y10T

Abstract:
A closed-loop controlled method for preventing contamination in a low pressure chemical vapor deposition chamber comprising the steps of:providing a chamber equipped with a vacuum port in fluid communication with a gate valve and a vacuum pump, connecting an exhaust vent in parallel with and bypassing said gate valve with a first conduit of the device connected to said vacuum port, a second conduit of the device connected to said vacuum pump and a middle conduit providing fluid communication between said first and said second conduit equipped with a pneumatic valve, said middle conduit being smaller than said first and second conduit such that a sufficiently higher fluid flow rate is generated in said middle conduit for preventing cumulation of reaction by-products in said middle conduit, one of said first and second conduit being equipped with a butterfly valve for adjusting a fluid flow therethrough, turning on said pneumatic valve with said vacuum pump operating and loading/unloading at least one wafer into/from said deposition chamber, and adjusting an angle of said butterfly valve by a controller such that a pre-set fluid flow rate through said second conduit is maintained.