Browse Prior Art Database

Ta2O5/Si3N4 Hard Mask/BARC for 248nm Lithography

IP.com Disclosure Number: IPCOM000016338D
Original Publication Date: 2002-Sep-19
Included in the Prior Art Database: 2003-Jun-21
Document File: 2 page(s) / 48K

Publishing Venue

IBM

Abstract

Disclosed is a combination hard mask and bottom anti-reflection coating (HM/BARC) for use in lithography at 248 nm. This coating is composed of Ta2O5/Si3N4. Its intended use is in "image transfer" patterning. In the "image transfer" method of fabricating thin film structures, a "hard mask" is patterned using photo lithography and RIE (Reactive Ion Etching). Subsequently, this hard mask image is transferred to a base layer or other underlying materials (oxides, metals, cured polymers) with a different RIE chemistry.

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Ta2O5/Si3N4 Hard Mask/BARC for 248nm Lithography

Disclosed is a combination hard mask and bottom anti-reflection coating (HM/BARC) for use in lithography at 248 nm. This coating is composed of Ta2O5/Si3N4. Its intended use is in "image transfer" patterning. In the "image transfer" method of fabricating thin film structures, a "hard mask" is patterned using photo lithography and RIE (Reactive Ion Etching). Subsequently, this hard mask image is transferred to a base layer or other underlying materials (oxides, metals, cured polymers) with a different RIE chemistry.

Prior art includes the use of Ta2O5 as a hard mask for the above process. Recent interest in patterning Ta2O5 with 248nm lithography requires an anti-reflection coating. Such an anti-reflection coating aids in the lithography process control by making the lithography process less sensitive to variations in resist, hard mask and base layer thickness. The currently disclosed structure is a bilayer Hard Mask that also acts as a bottom anti-reflection coating (BARC) at 248nm. The first layer is Ta2O5 and the second is Si3N4. These materials both act as a hard mask and can be sputtered in the thickness needed at low temperature.

As a demonstration of its effectiveness experiments with this structure have been carried out and summarized in figure 1, below. The "Base Layer" is a cured photopolymer, and the HM/BARC combination is 1740 Å of sputtered Ta2O5 with 221 Å of Ion-Beam deposited Si3N4 (nominal compositi...