Challenges and opportunities in applying grapho-epitaxy DSA lithography to metal cut and contact/via applications

Contact layer decomposition to enable DSA with multi-patterning technique for standard cell based layout

“…As discussed in [4], [8], the qualities of the guiding templates are usually positively correlated with the size. 1D templates are preferred over 2D as the diagonal contact pairs have irregular pitch, in contrast to the natural pitch of the DSA process.…”

“…Because DSA is currently aiming at 7 nm technology, where the guiding template generation needs either double patterning EUV or multiple patterning DUV process, by incorporating DSA into the multiple patterning process, it is possible to reduce the number of masks and achieve a cost effective solution [8]. Furthermore, it can split the contact patterns into simpler and thus more favorable guiding templates.…”

Mask assignment and synthesis of DSA-MP hybrid lithography for sub-7nm contacts/vias

“…In addition, smaller defects density can be obtained with smaller size of templates [4,9,15]. Accordingly templates should be designed such that a very small number of contacts are created per template [12]. In addition, previous research has reported that using peanut-shaped templates with a very narrow neck between every pair of contacts can lead to less placement error [12].…”

“…Accordingly templates should be designed such that a very small number of contacts are created per template [12]. In addition, previous research has reported that using peanut-shaped templates with a very narrow neck between every pair of contacts can lead to less placement error [12]. However well-modulated peanut shapes are hard to print in 193i photolithography, therefore it is preferred to have the pitch of grouped contacts close to the natural pitch of the copolymer, not to have more than one single pitch value in one DSA group and to avoid 2D groups altogether [12].…”

“…Thus, whether EUVL comes into play or not, Multiple Patterning is expected to enable several sub-7nm nodes. With the cost being the main drawback of MP and with DSA having native frequency multiplication properties, substituting one mask in an MP process with DSA is a tempting cost reduction [12]. In addition, DSA has been reported to possess Permission to make digital or hard copies of all or part of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page.…”