Novel metal containing resists for EUV lithography extendibility

Abstract

Strong interest has recently developed among the researchers in the use of metals in extreme ultraviolet (EUV) lithography photoresists [1,2] aiming to simultaneously achieve the resolution, line-width roughness and sensitivity (RLS) requirements for 10nm technology node and below and have the highest productivity with low exposure dose requirements (below 20mJ/cm2). In this paper two different metal containing resists (MCR) are discussed: the first one uses metal oxide nanoparticles (NP) bonded with ligands as an alternative non chemically amplified EUV photoresist; the second one introduces a metal species (the sensitizer) into a conventional chemically amplified EUV photoresist. In both cases, the metal is added to the resist system to increase the absorption of EUV photons as well as increase the generation of secondary electrons, thereby making more effective use of the dose. The initial work is focused on manufacturing compatibility, concerning metal cross-contamination, outgassing and hydrides formation risk. Next, lithographic performance is evaluated with respect to the RLS requirements by patterning on NXE:3300 full field scanner exposure tool, with particular emphasis on the material stability of different formulations.. Finally, imaging results at different processing conditions are also reported and discussed.

Absorption coefficient of metal-containing photoresists in the extreme ultraviolet

“…6 For instance, the resolution-linewidth roughness-sensitivity tradeoff postulates that these three characteristics cannot be improved simultaneously owing to the mutual dependencies among one another, 9 which sets an insurmountable limitation to CAR. Entirely new approaches in photoresists' functionality and synthesis are instead being undertaken, among which hybrid organometallic photoresists, 10 oxide nanoparticles, 11,12 and condensed molecular oxides, 6,13 testify to the intense scientific research in this field. In particular, hybrid oxide resists that are synthesized from metallic elements and/or high Z-number elements have shown a remarkable combination of features (high resolution, high etch resistance, and compatibility with existing processes) that makes them promising for EUV lithography.…”

Promising Lithography Techniques for Next-Generation Logic Devices

“…Nonchemically amplified resists (non-CARs) show high-resolution capability, high sensitivity and low LER as they have no acid diffusion issues. Some researchers have reported the development of the metal containing photoresist that has high sensitivity performance, which will be very helpful for the low-energy power source to realize EUVL [21,22]. Some other new techniques including nanoparticle photoresists with high sensitivity have been reported [23][24][25][26].…”

Recent Progress in EUV Metal Oxide Photoresists

“…However, severe scum in the unexposed area was observed when a 1:1 dense pattern was checked. Various improvement studies were attempted at IMEC [10] but continuous improvement was required to achieve better resolution with dense patterns using Zr type metal oxide photoresists. For scum improvement, the dissolution rate acceleration concept was tested at this time for scum removal from unexposed areas.…”