X-ray transmitting membrane for mask in x-ray lithography and method for preparing the same
AssigneeShin-Etsu Chemical Co., Ltd.
InventorsMeguru Kashida, Yoshihiko Nagata, Hitoshi Noguchi
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Abstract
Disclosed is an X-ray transmitting frame-supported membrane of silicon nitride suitable as a mask blank of an X-ray lithographic mask having outstandingly high resistance against irradiation with high-energy radiations and high transmission of light of a wavelength of 633 nm. These very desirable properties are obtained as a consequence of the extremely low content, i.e. 1.0 atomic % or less, of hydrogen in the silicon nitride, which can be achieved as a result of the specific preparation procedure by the CVD method in which the reactant gases are silane or disilane and ammonia in a specified mixing ratio to be reacted under a specified pressure and at a specified temperature.
Claims4
An X-ray transmitting frame-supported membrane of silicon nitride having a thickness in the range from 0.1 to 10 .mu.m formed by the method of chemical vapor-phase deposition from a silicon-containing compound and a nitrogen-containing compound as the reactant gases, of which the content of hydrogen does not exceed 1.0 atomic % and transmission of light having a wavelength of 633 nm therethrough is at least 70%.
Dependencies are inferred from the claim text.