Patent ID: 6537707
Filing Date: 2003-03-25
Classification: C23C

Abstract:
A method of fabricating a high energy radiation mask comprising steps of:locating a substrate in a vacuum chamber; activating a first roughing evacuation connection to said vacuum chamber, said first roughing evacuation connection having a first maximum rate of evacuation; detecting when pressure within said vacuum chamber is reduced to a first threshold pressure; activating a second roughing evacuation connection to said vacuum chamber in response to detecting that said pressure is below said first threshold pressure, said second roughing connection having a second maximum rate that is greater than said first maximum rate; detecting when pressure within said vacuum chamber is reduced to an intermediate threshold pressure that is between said first threshold pressure and a second threshold pressure; deactivating said first roughing evacuation connection in response to detecting that said pressure within said vacuum chamber is below said intermediate threshold pressure, thereby providing a range between said first and intermediate threshold pressures in which said first and second roughing evacuation connections are simultaneously activated; detecting when pressure within said vacuum chamber is reduced to said second threshold pressure; activating a high vacuum pump connection to said vacuum chamber in response to detecting that said pressure is below said second threshold pressure; and depositing at least one layer on said substrate within said vacuum chamber to form a coating that is resistant to damage when exposed to a high energy beam.