Patterning highly ordered arrays of complex nanofeatures through EUV directed polarity switching of non chemically amplified photoresist

Abstract

Given the importance of complex nanofeatures in the filed of micro-/nanoelectronics particularly in the area of high-density magnetic recording, photonic crystals, information storage, micro-lens arrays, tissue engineering and catalysis, the present work demonstrates the development of new methodology for patterning complex nanofeatures using a recently developed non-chemically amplified photoresist (n-CARs) poly(4-(methacryloyloxy)phenyl)dimethylsulfoniumtriflate) (polyMAPDST) with the help of extreme ultraviolet lithography (EUVL) as patterning tool. The photosensitivity of polyMAPDST is mainly due to the presence of radiation sensitive trifluoromethanesulfonate unit (triflate group) which undergoes photodegradation upon exposure with EUV photons, and thus brings in polarity change in the polymer structure. Integration of such radiation sensitive unit into polymer network avoids the need of chemical amplification which is otherwise needed for polarity switching in the case of chemically amplified photoresists (CARs). Indeed, we successfully patterned highly ordered wide-raging dense nanofeatures that include nanodots, nanowaves, nanoboats, star-elbow etc. All these developed nanopatterns have been well characterized by FESEM and AFM techniques. Finally, the potential of polyMAPDST has been established by successful transfer of patterns into silicon substrate through adaptation of compatible etch recipes.

Green Nanofabrication Opportunities in the Semiconductor Industry: A Life Cycle Perspective

“…EUVL is an extension of optical lithography that specifically employs light in the EUV region of 13.5 nm [ 144 , 162 , 163 ]. EUVL is used for its efficient development and manufacturing cycle time, increased number of patterning levels, and its addressing the overall complexity of extending multiple patterning into higher multiples [ 33 ].…”

“…Making this high power process economical is one of the most challenging obstacles that must be overcome for the use of EUVL in industry [ 16 , 154 , 167 ]. Furthermore, EUVL typically requires extensive use of chemicals: thermoplastic, molecular glass or fullerene derived resists, and acid generators and acid amplifiers [ 163 , 168 , 169 ]. The more precise the process the more likely a longer list of chemicals would be required, adding to the complexity of environmental risk assessments.…”

Novel Star Polymers as Chemically Amplified Positive-Tone Photoresists for KrF Lithography Applications

“…7 However, a balance exists between the resolution, line edge roughness (LER), and sensitivity of CA resists, as shown in the following formula: resolution 3 × LER 2 × sensitivity ≈ constant. 8 The main challenge of this technology is to increase the resolution and sensitivity of photoresists with lower LER to meet the advanced lithgraphy. 9 Polymer resin is the backbone of resists, contributing to all aspects of resist performance and character.…”

“…CA resist based on acid deprotection is the main foundation for 248, 193 nm resist systems that are mainly used in deep ultraviolet (DUV) lithography technology for integrated circuit device manufacturing . However, a balance exists between the resolution, line edge roughness (LER), and sensitivity of CA resists, as shown in the following formula: resolution 3 × LER 2 × sensitivity ≈ constant . The main challenge of this technology is to increase the resolution and sensitivity of photoresists with lower LER to meet the advanced lithgraphy …”

Polyarylenesulfonium Salt as a Novel and Versatile Nonchemically Amplified Negative Tone Photoresist for High-Resolution Extreme Ultraviolet Lithography Applications

“…Complex nanofeatures such as nanodots, nanopillars, nanorings, and star-elbow features often find special interest in the semiconductor industry because of their applicability in diverse fields. − PAS is capable of patterning complex nanofeatures including nanodots, nanorings, and star-elbow features under EUVL conditions. HR-AFM images shown in Figure a,b reveal dense arrays of nanodots with feature sizes ranging from 34, 36, 40, 45, 50 to 60 nm.…”