Amorphous silicon (a-Si) gates with a length of 20 nm have been obtained in a “line & cut” double patterning process. The first pattern was printed with extreme ultraviolet photoresist (PR) and had a critical dimension (CD) close to 30 nm, which imposed a triple challenge on the etch: limited PR budget, high line width roughness, and significant CD reduction. Combining a plasma pre-etch treatment of the PR with the etch of the appropriate hard mask underneath successfully addressed the two former challenges, while the latter one was overcome by spreading the CD reduction on the successive layers of the stack.
MTJ stack is optimized for TMR at low RA region, high PMA and 400oC post annealing
capability. Atomic level smooth bottom electrode with 0.5A roughness was developed and positive effects on
annealing capability and PMA was demonstrated. The scaling challenge of STT-MRAM read operation down
to sub-10nm is discussed. Various contributing factors to the MTJ cell resistance variation were investigated
with focus on MRAM cell variation due to advanced lithography patterning techniques. With SADP or DSA,
the MRAM cell size can be scaled down to 18nm physical dimension with 4.2% σ/μ cell area variation, good
enough for sub-10nm technology node.
Amorphous silicon (a-Si) gates with a length of 20nm have been obtained in a ‘line & cut’ double patterning process. The first pattern was printed with EUV photoresist and had a critical dimension close to 30nm, which imposed a triple challenge on the etch: limited photoresist budget, high line width roughness and significant CD reduction. Combining a plasma pre-etch treatment of the photoresist with the etch of the appropriate hard mask underneath successfully addressed the two former challenges, while the latter one was overcome by spreading the CD reduction on the successive layers of the stack.
Kaidong Xu, Laurent Souriau, David Hellin, Janko Versluijs, Patrick Wong, Diziana Vangoidsenhoven, Nadia Vandenbroeck, Harold Dekkers, Xiaoping Shi, Johan Albert, Chi Lim Tan, Johan Vertommen, Bart Coenegrachts, Isabelle Orain, Yoshie Kimura, Vincent Wiaux, Werner Boullart
The approach for patterning 15-nm half-pitch (HP) structures using extreme ultraviolet lithography combined with self-aligned double patterning is discussed. A stack composed of a double hard mask, which allows decoupling photoresist transfer and trim, and an α-Si mandrel, which offers better mechanical properties during the mandrel and spacer patterning, is proposed. A break-down study with the patterning steps was performed to investigate the key contributors for improvement of linewidth roughness (LWR), line-edge roughness (LER), and critical dimension uniformity (CDU), targeting integrated solutions with lithography, etch, thin film deposition, and wet cleans for selected applications. Based on the optimization of these key patterning contributors, optimum LWR, LER, and CDU at 15 nm HP are demonstrated.
K. Xu, L. Souriau, D. Hellin, J. Versluijs, P. Wong, D. Vangoidsenhoven, N. Vandenbroeck, H. Dekkers, X. Shi, J. Albert, C. Tan, J. Vertommen, B. Coenegrachts, I. Orain, Y. Kimura, V. Wiaux, W. Boullart
This paper discusses the approach for patterning 15nm Half Pitch (HP) structures using EUV lithography combined with Self-Aligned Double Patterning (SADP). A stack composed of a double hard mask, which allows decoupling photoresist transfer and trim, and an α-Si mandrel, which offers better mechanical properties during the mandrel and spacer patterning, is proposed. A break-down study with the patterning steps was performed to investigate the key contributors for improvement of LWR, LER and CDU, targeting integrated solutions with lithography, etch, thin film deposition, and wet cleans for selected applications. Based on the optimization of these key patterning contributors, optimum LWR, LER and CDU at 15nm HP are demonstrated.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.