Lithographic Resists

Abstract

This article provides an overview of the chemistry and processes used to form micro‐ and nanoscale patterns for the fabrication of semiconductors and other electronic devices. The basic functional attributes of lithographic resists and the physical principles of modern lithographic process technologies are addressed. The imaging chemistry of the major classes of resists in current use is described. A detailed discussion of chemically amplified resists, the most widely used class of resist, summarizes their evolutionary development, mechanisms of imaging chemistry, key processing characteristics, and factors that limit ultimate extendibility. A number of newly emerging techniques for lithographic patterning are described.

Photodegradable Polyurethane Resist with High Photosensitivity Based on Hexaarylbiimidazole Molecule Photoswitch

“…Compared with highly sensitive chemical amplification resists, HABI-PU PR has a slightly lower contrast. 1,49 Nevertheless, the contrast verified the sensitivity of HABI-PU PR to 365 nm illumination once again.…”

“…Furthermore, after the logarithmic processing of Figure j, the contrast curve of HABI-PU PR when the molar percentage of HABI is 12% is obtained, and the calculated contrast is about 1.39 (Figure S7 and Note S5). Compared with highly sensitive chemical amplification resists, HABI-PU PR has a slightly lower contrast. , Nevertheless, the contrast verified the sensitivity of HABI-PU PR to 365 nm illumination once again.…”

“…Photoresists could be divided into positive and negative resists, usually composed of photosensitizers, matrix resins, solvents, and other auxiliaries . Exposed to ultraviolet (UV) light with a specific wavelength, the polymer chains in positive photoresists will undergo depolymerization, or the deprotection reaction will happen, making the photoresist more easily dissolved in the developer. − Therefore, this region receiving illumination in photoresist would dissolve in the specific developer, while the chemical properties of the unilluminated part are not affected.…”

Role of resist components in electron emission and capture

“…These acids then react with the polymer protecting group, causing changes in the polymer solubility. 2,3 For metal-oxide (MOx) resists, a different mechanism is proposed. In this case, either EUV photons or the generated primary and secondary electrons cause the cleavage of organic ligands that protect metal-oxide clusters.…”

Experimental characterization of model extreme ultraviolet resist materials

“…In chemically amplified photoresists, the attachment of slow electrons to photoacid generator molecules leads to the formation of acids, which react with the polymer's protecting group, leading to changes in polymer solubility. 2,3 A different solubility change mechanism is postulated for metal-oxide (MOx) resists: either EUV photons or generated primary and secondary electrons lead to the cleavage of organic ligands, protecting metal-oxide clusters, and to the condensation of metal-oxide clusters with formation of metal-oxygen bonds. [4][5][6] Because of the crucial role that the electrons play in EUV lithography, it is critically important to understand all processes initiated by electron-resist interactions as well as primary and secondary electron generation mechanisms and efficiencies, energies of generated electrons, and the length scale on which the electrons can propagate upon ionization.…”