Large-area silicon–nitride mask technology for x-ray lithography

This paper describes a technology for making large area silicon-nitride x-ray masks. We did extensive work for optimizing the LPCVD deposition process. Choosing proper deposition parameters, we obtained silicon-nitride layers with low tensile stress. Using the ion implantation stress compensation technique, the stress of the silicon nitride was reduced until the desirable value was reached. The key parameters of the silicon-nitride mask are satisfactory for the needs of x-ray masks used to fabricate VLSI devices. Because the silicon-nitride film is stoichiometric, a good stability of the mask is expected; tests of its stability to x-ray radiation are being continued at IMT.