56 nm pitch Cu dual-damascene interconnects with self-aligned via using negative-tone development Lithography-Etch-Lithography-Etch patterning scheme

2015 IEEE International Interconnect Technology Conference and 2015 IEEE Materials for Advanced Metallization Conference (IITC/

Broussous

Zoll

et al. 2015

Section: Introductionmentioning

confidence: 99%

Cobalt compatible cleaning solutions for 14nm and beyond

2015 IEEE International Interconnect Technology Conference and 2015 IEEE Materials for Advanced Metallization Conference (IITC/

Broussous

Zoll

et al. 2015

“…As the technology node advances, new integration schemes have to be used for the patterning of features below 80 nm pitch with 193 nm immersion lithography. In particular, thicker TiN-HM is necessary in order to ensure Self-Aligned-Via (SAV) integration which resolves via-metal short yield and TDDB issues caused by Litho-Etch-Litho-Etch (LELE) misalignment [2,3]. The Cu filling process is significantly more difficult if the thick TiN is not removed because of the high aspect ratio of the structures.…”

Section: Introductionmentioning

confidence: 99%

“…Thick-TiN-HM removal utilizing a SiCN retention scheme without Cu exposure was developed (Fig. 1(a)) and showed good electrical and reliability performance [3] but there still remains room for cost reduction for industrial challenges. In this paper, we demonstrated Thick-TiN-HM removal process by using all-in-one wet scheme (Fig.…”

Section: Introductionmentioning

confidence: 99%

Industrial Challenges of TiN Hard Mask Wet Removal Process for 14nm Technology Node

Iwasaki

Lippy

et al. 2014

SSP

TiN Hard Mask (TiN-HM) integration scheme has been widely used for BEOL patterning in order to avoid ultra low-k (ULK) damage during plasma-ash process [1]. As the technology node advances, new integration schemes have to be used for the patterning of features below 80 nm pitch with 193 nm immersion lithography. In particular, thicker TiN-HM is necessary in order to ensure Self-Aligned-Via (SAV) integration which resolves via-metal short yield and TDDB issues caused by Litho-Etch-Litho-Etch (LELE) misalignment [2, 3]. The Cu filling process is significantly more difficult if the thick TiN is not removed because of the high aspect ratio of the structures. Moreover, with the use of TiN hard mask, a time-dependent crystal growth (TiCOF) residue may forms between line etch and metal deposition [4, 5], also hindering copper filling. Post-Etch-Treatment after line etching is one solution to the problem but N2plasma is not efficient enough to suppress the residue completely [6], and the CH4treatment proposed in [5] may be difficult to implement for 14 nm node, thus an efficient wet strip and clean provides a better solution.

“…This integration scheme was successfully used for a BEOL pitch down to 90 nm for the 28 nm node, however, for the 14 nm technology node, 64 nm BEOL minimum pitch is required for the first metal levels. Because it is unable to resolve features below 80 nm pitch in a single exposure, conventional 193 nm immersion lithography must be associated with dual patterning schemes, so called Lithography-Etch-Lithography-Etch (LELE) patterning [3] for line levels and self-aligned via (SAV) process [4] for via patterning. In both cases, 2 lithography/etch/clean sequences are necessary to obtain one desired pattern, and associated reworks also become more challenging since first pattern is exposed to resist removal processes (plasma + wet clean).…”

Section: Introductionmentioning

confidence: 99%

TiN Hard Mask Cleans with SC1 Solutions, for 64nm Pitch BEOL Patterning

Broussous

Krejcirova

et al. 2014

SSP

Titanium Nitride metal hard mask was first introduced for BEOL patterning at 65 nm [1] and 45 nm nodes [2]. Indeed, in this “Trench First Hard Mask” (TFHM) backend architecture, the dual hard mask stack (SiO2 & TiN) allows a minimized exposure of ULK materials to damaging plasma chemistries, both for line/via etch sequence, and lithography reworks operations. This integration scheme was successfully used for a BEOL pitch down to 90 nm for the 28 nm node, however, for the 14 nm technology node, 64 nm BEOL minimum pitch is required for the first metal levels. Because it is unable to resolve features below 80 nm pitch in a single exposure, conventional 193 nm immersion lithography must be associated with dual patterning schemes, so called Lithography-Etch-Lithography-Etch (LELE) patterning [3] for line levels and self-aligned via (SAV) process [4] for via patterning. In both cases, 2 lithography/etch/clean sequences are necessary to obtain one desired pattern, and associated reworks also become more challenging since first pattern is exposed to resist removal processes (plasma + wet clean). The reference wet cleans that were developed for 65 to 28 nm TiN hardmask patterning, utilizes commonly used chemistry for BEOL post-etch cleans, i.e. diluted hydrofluoric acid (dHF) followed by deionized water Nanospray (DIWNS) on 300 mm single wafer tool.