File:Twice applied SID.png

English: Spacer-is-dielectric patterning (applied twice for SAQP) with single exposure. The blue features are the mandrels, and the red features are the post-(anti-)spacer fill features. After first (anti-)spacer removal, the red fill and blue mandrel feature sizes for subsequent spacer patterning (e.g., trimmed to half original width) as shown may be achieved by lateral etching as needed.^[1] Pitch quartering (after pitch halving) is achieved by repeating the same SID flow, adding the green features. ^[2][3] Note that the (anti-)spacers do not need to be cut since anti-spacers are removed anyway^[4] and in any case even as spacers they do not define any conducting loops, i.e., the spacer represents dielectric.

1. ↑ Wet chemical hardmask trim
2. ↑ Y. Ban and D. Z. Pan, J. Micro/Nanolith. MEMS MOEMS 14, 011004 (2015).
3. ↑ C. Kodama et al., IEEE Trans. CAD Integ. Circ. and Syst., vol. 34, 753 (2015).
4. ↑ M. Hyatt et al., Proc. SPIE vol. 9051, 905118 (2014).