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Alternative Masking Materials for Photomasking

IP.com Disclosure Number: IPCOM000043483D
Original Publication Date: 1984-Sep-01
Included in the Prior Art Database: 2005-Feb-04
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Bergendahl, AS: AUTHOR [+3]

Abstract

Instead of depositing multicoated layers on the chrome surface to reduce the high reflectivity of chrome on photomasks, which degrades the modulation transfer functions at the wafer plane, this article proposes alternate metal masking materials for photomasking. Chrome carbonyl is replaced with less reflective metal carbonyls, such as iron [Fe(CO)5], molybdenum [Mo(CO)6], nickel [Ni(CO)4], tungsten [W(CO)6], or cobalt [Co2(CO)8] carbonyls, which deposit a lower reflectivity metal layer on the substrate while still being conductive enough for use with E-beam pattern definition. The deposited metal is in a very inert form while using even normally unstable metals, such as iron. The deposition method makes these metals stable enough not to oxidize under normal conditions.

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Alternative Masking Materials for Photomasking

Instead of depositing multicoated layers on the chrome surface to reduce the high reflectivity of chrome on photomasks, which degrades the modulation transfer functions at the wafer plane, this article proposes alternate metal masking materials for photomasking. Chrome carbonyl is replaced with less reflective metal carbonyls, such as iron [Fe(CO)5], molybdenum [Mo(CO)6], nickel [Ni(CO)4], tungsten [W(CO)6], or cobalt [Co2(CO)8] carbonyls, which deposit a lower reflectivity metal layer on the substrate while still being conductive enough for use with E-beam pattern definition. The deposited metal is in a very inert form while using even normally unstable metals, such as iron. The deposition method makes these metals stable enough not to oxidize under normal conditions. The actual choice of metal requires a determination of the optimum reflectivity for photolithographically made masks and the optimum reflectivity-conductivity trade-off combination for E-beam masks.

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