Progress in metal organic cluster EUV photoresists

Abstract

Most advanced microelectronic devices are made by using 193 nm immersion lithography systems, but it is difficult to follow the rapid development of semiconductors due to their approaching physical limits. Extreme ultraviolet (EUV) lithography which uses a shorter wavelength (i.e., 13.5 nm) light source can offer a way to print features under a 20 nm HP. EUV lithography requires photoresists that utilize EUV photons because photons generated by EUV exposure are fewer than photons generated by 193 nm light exposure. In this paper, our recent progress in metal oxide photoresist research will be discussed.

Molecular Layer Deposition of a Hafnium-Based Hybrid Thin Film as an Electron Beam Resist

“…One type of resist, termed an inorganic resist, − is attracting increased attention. These resists consist of inorganic nanoparticles such as hafnium oxide, − titanium oxide, or zirconium oxide , that are surface decorated with organic ligands such as methacrylic acid. These inorganic resists have several advantages over their organic counterparts: they are more resistant to etching, especially dry etching, are more absorbing of extreme ultraviolet (EUV), and are more resistant to pattern collapse because they are structurally more stable .…”

Novel hexameric tin carboxylate clusters as efficient negative-tone EUV photoresists: high resolution with well-defined patterns under low energy doses

“…Inorganic complexes are promising photoresist materials in EUV (extreme ultraviolet) lithography. [1][2][3][4] One obvious advantage is that the EUV absorption efficiencies of metal complexes such as Hf, [5][6][7][8][9][10][11][12] Zr, [13][14][15][16][17][18] Zn, 10,19,20 and Sn [21][22][23][24][25] are 2-3 folds as large as those of polymer-based photoresists. Despite intensive studies, very few inorganic photoresists 3,19 can reach high resolution EUV patterns with half pitches (HPs) <20 nm under low dosage <50 mJ cm −2 .…”

Structural investigation of zinc‐based photoresists with different substituents for high‐resolution lithography

“…Kinds of metal‐based photoresists have been investigated, including metal nanoparticles, 10,11 metal–oxo clusters (MOCs), 5,12–14 polymer‐metal complex, 15–17 quantum dots (QDs), 18 and metal–organic frameworks (MOFs) 19–21 . Particularly, metal–oxo clusters obtained significant attention, being regarded as a potential candidate of the EUV photoresist, 22,23 for their molecularly defined structure (small and homogeneous in size) anticipated to prevent variations in the nanopatterns for lower line edge roughness (LER) values 24,25 .…”