Pulsed Transfer Etching of PS–PDMS Block Copolymers Self-Assembled in 193 nm Lithography Stacks

Abstract

This work presents the graphoepitaxy of high-χ block copolymers (BCP) in standard industry-like lithography stacks and their transfer into the silicon substrate The process includes conventional 193 nm photolithography, directed self-assembly of polystyrene-block-polydimethylsiloxane (PS-b-PDMS) and pulsed plasma etching to transfer the obtained features into the substrate. PS-b-PDMS has a high Flory-Huggins interaction parameter (high-χ) and is capable of achieving sub-10 nm feature sizes. The photolithography stack is fabricated on 300 mm diameter silicon wafers and is composed of three layers: spin-on-carbon (SoC), silicon-containing anti-reflective coating (SiARC) and 193 nm photolithography resist. Sixty-nanometer-deep trenches are first patterned by plasma etching in the SiARC/SoC stack using the resist mask. The PS-b-PDMS is then spread on the substrate surface. Directed self-assembly (DSA) of the BCP is induced by a solvent vapor annealing process and PDMS cylinders parallel to the substrate surface are obtained. The surface chemistry based on SoC permits an efficient etching process into the underlying silicon substrate. The etching process is performed under dedicated pulsed plasma etching conditions. Fifteen nanometer half-pitch dense line/space features are obtained with a height up to 90 nm.

Technological strategies for self-assembly of PS-b-PDMS in cylindrical sub-10 nm nanostructures for lithographic applications

“…for lithographic applications [55]. Among the various silicon-containing BCPs, polystyrene-b-polydimethylsiloxane (PS-b-PDMS) DBC [20,56] (Figure 3(a)) has been recognized as the reference material, because of its high Flory-Hugging interaction parameter χ AB (0.26 at 300 K) [57] resulting in the formation of nanostructures with minimum feature size around 8 nm [58,59].…”

“…In this context, Jung et al [61] exploited parallel cylinders self-assembled PS-b-PDMS on patterned silica substrate to fabricate wire structures by means of 300 W CF 4 RIE process for 30 s. In the condition described in the article, the etching rates of the oxidized PDMS and of the silica are quite similar (~0.7 nm/s), permitting an etching ratio cylinder/wire around 1:1. Alternatively, Girardot et al [55] fabricated periodic silicon line patterns using the hard mask generated by the self-assembly of PS-b-PDMS in parallel-oriented cylinder deposited on spin-on-carbon (SoC)/silicon-containing anti-reflective coating (SiARC) layer. The transferring of the oxidized PDMS stripes pattern was performed by a dedicated pulsed Hbr/O 2 plasma etching condition.…”

Nanoscale silicon substrate patterns from self-assembly of cylinder forming poly(styrene)-block-poly(dimethylsiloxane) block copolymer on silane functionalized surfaces

“…The sequential pattern transfer process involves initial sequential CF 4 and O 2 plasma etches to remove the upper wetting PDMS layer and the PS matrix as well as oxidize the PDMS cylinders (ETCH1). This results in the PDMS patterns forming silica-type structures which can be subsequently utilized as a hard mask [17], [45], [46]. It should be noted that during the O 2 etch, special care is required in order to minimize the undercut of the PDMS cylinders which can lead to poor quality pattern transfer.…”

Facile non‐lithographic route to highly aligned silica nanopatterns using unidirectionally aligned polystyrene‐block‐polydimethylsiloxane films

“…SVA‐S has been shown to align a number of BCP systems, including polystyrene‐ block ‐polyisoprene‐ block ‐polystyrene, polystyrene ‐block ‐polybutadiene‐ block ‐polystyrene, polystyrene ‐block ‐poly( N,N ‐dimethyloctadecylammonium styrene sulfonate), polystyrene‐ block ‐poly(2‐vinylpyridine), and polystyrene‐ block ‐polydimethylsiloxane (PS‐ b ‐PDMS). Of particular interest is the PS‐ b ‐PDMS system, which has attracted broad interest from a number of researchers . This interest is primarily due to two reasons.…”