Additive Lithography–Organic Monolayer Patterning Coupled with an Area-Selective Deposition

Abstract

The combination of area-selective deposition (ASD) with a patternable organic monolayer provides a versatile additive lithography platform, enabling the generation of a variety of nanoscale feature geometries. Stearate hydroxamic acid selfassembled monolayers (SAMs) were patterned with extreme ultraviolet (λ = 13.5 nm) or electron beam irradiation and developed with ASD to achieve line space patterns as small as 50 nm. Density functional theory was employed to aid in the synthesis of hydroxamic acid derivatives with optimized packing density to enhance the imaging contrast and improve dose sensitivity. Near-edge X-ray absorption fine structure spectroscopy and infrared spectroscopy reveal that the imaging mechanism is based on improved deposition inhibition provided by the cross-linking of the SAM to produce a more effective barrier during a subsequent deposition step. With patterned substrates composed of coplanar copper lines and silicon spacers, hydroxamic acids selectively formed monolayers on the metal portions and could undergo a pattern-wise exposure followed by ASD in the first combination of a patternable monolayer with ASD. This material system presents an additional capability compared to traditional ASD approaches that generally reflect a starting patterned surface. Furthermore, this bottoms-up additive approach to lithography may be a viable alternative to subtractive nanoscale feature generation.

Enhancing Performance and Function of Polymethacrylate Extreme Ultraviolet Resists Using Area-Selective Deposition

“…32 For example, metal oxides have demonstrated higher etch resistance than traditional organic resists and are a good candidate for resist hardening applications. 5,18,19 As shown in Figure 1c, two approaches for resist hardening include ASD of an etch resistant layer on a patterned resist (in which case the resist serves as the growth surface and rapid nucleation is desirable) 32,33 and selective reactant infiltration into the patterned resist (which takes advantage of small precursors selectively diffusing into a polymer). 34−36 In either case, the reaction can proceed on the as-prepared resist pattern or after exposure to a nucleation inhibitor.…”

Copper Oxidation Improves Dodecanethiol Blocking Ability in Area‐Selective Atomic Layer Deposition

“…[ 3–9 ] For the surface modification step, self‐assembled monolayers (SAMs) are often used as the inhibitors to protect surfaces from the subsequent deposition step. [ 10–17 ] As for the deposition step, atomic layer deposition (ALD) is considered an excellent vehicle because ALD strongly depends on the surface properties of the substrates due to the self‐limiting reactions between precursors and growth surfaces. In addition, the advantages provided by ALD, including atomic‐level thickness control, excellent conformality, and uniformity, have made ALD a key tool for advanced semiconductor fabrication processing.…”

“…[3][4][5][6][7][8][9] For the surface modification step, self-assembled monolayers (SAMs) are often used as the inhibitors to protect surfaces from the subsequent deposition step. [10][11][12][13][14][15][16][17] As for the deposition step, atomic layer deposition (ALD) is considered an excellent vehicle because ALD strongly depends on the surface properties of the substrates due to the self-limiting reactions between precursors and growth surfaces. In addition, the advantages provided by ALD, including atomic-level thickness control, excellent conformality, and uniformity, have made ALD a key tool for advanced semiconductor fabrication processing.One targeted application for area-selective atomic layer deposition (AS-ALD) is to selectively deposit dielectrics as an etch hard mask on the dielectric regions of metal/dielectric patterns for the fabrication of fully aligned vias in back-end semiconductor processes.…”

The role of atomic oxygen in the decomposition of self-assembled monolayers during area-selective atomic layer deposition

“…Area selective ALD (AS-ALD) is proposed as a method for preferentially depositing a material on a specific area on the surface while the remainder is left uncoated, giving control over a deposited thin film in the horizontal plane [4][5][6][7][8]. One approach being adopted to achieve area selective ALD is through the use of selfassembled monolayers (SAMs) which can assist in the patterning of microscale and nanoscale features [9][10][11][12][13][14][15][16]. The adaptability of the SAM chemistry makes them a prime candidate for selectively adhering to particular sections of the surface allowing them to block any subsequently deposited material.…”