Comparative study of sputtered and spin-coatable aluminum oxide electron beam resists

Abstract

Articles you may be interested inSpin-coatable Hf O 2 resist for optical and electron beam lithographies J. Vac. Sci. Technol. B 28, 90 (2010); 10.1116/1.3273536 Polysubstituted derivatives of triphenylene as high resolution electron beam resists for nanolithography J.Control of the structure and properties of aluminum oxide coatings deposited by pulsed magnetron sputtering J. Vac. Sci. Technol. A 17, 945 (1999); 10.1116/1.581669 Magnetic nanostructures produced by electron beam patterning of direct write transition metal fluoride resistsThe electron beam exposure characteristics of sputtered AlO x and spin-coatable Al 2 O 3 resists are compared and contrasted. When exposed to an electron beam, sputtered AlO x resists on a silicon substrate undergo an intense mass loss. However, electron energy loss spectroscopy shows that even after a prolonged exposure some aluminum and oxygen remains on the silicon surface. Spin-coatable Al 2 O 3 resist was prepared by reacting aluminum tri-sec-butoxide, Al͑OBu s ) 3 , with acetylacetone ͑AcAc͒ in isopropyl alcohol. These are negative tone resists and they are Ͼ10 6 times more sensitive to an electron beam than the sputtered AlO x , bringing its sensitivity very close to high resolution organic resists such as calixarene. The exposure properties of spin-coatable and sputtered aluminum oxide resists are discussed together with their sensitivity, damage mechanisms, line edge roughness, and etching characteristics. A brief note on the change of methodology of resist design is added when inorganic resists are to be used in high resolution electron beam nanolithography.

Solid-State Nanopore Sensors for Nucleic Acid Analysis

“…Amorphous Al 2 O 3 is sputtered primarily via volume dissociated mechanisms exhibiting rapid and abrupt mass-loss, attributed to the displacement of metallic Al and the formation of oxygen gas bubbles due to anion aggregation. [143], [144] This mechanism explains the rapid pore [133,143] The decreased yet constant expansion rate observed in stage III of figure 21b is consistent with this result. Mochel et al also reported steady, constant growth rates during the formation of nanometer sized holes in metal β-aluminas.…”

DNA Sensing Using Nanocrystalline Surface‐Enhanced Al2O3 Nanopore Sensors

“…Amorphous Al 2 O 3 is sputtered primarily via volume dissociated mechanisms exhibiting rapid and abrupt mass-loss, attributed to the displacement of metallic Al and the formation of oxygen gas bubbles due to anion aggregation. [21], [22] This mechanism explains the rapid pore expansion initially observed (stage II of Figure 2b). With continued electron beam irradiation, the amorphous Al 2 O 3 support transitions into a hybrid polycrystalline-metallic structure (O to Al ratio of ~0.6).…”

Resists for sub-20-nm electron beam lithography with a focus on HSQ: state of the art

“…Under e-beam exposure, the naphthenate molecules are cross-linked, increasing the molecular weight of the resist, making it insoluble in the developer. In comparison to sputtered materials, the sensitivity seems to increase by almost a factor of 10 6 when resists are spin coated and if their structure is chemically changed [52,53]. For example, the spin-coatable Al 2 O 3 resists show an e-beam sensitivity of approximately 50 mC cm −2 , whereas for the sputtered Al 2 O 3 resist the electron dose is about 5 × 10 6 mC cm −2 .…”

“…Compared with the sputtered metal oxide resists, under e-beam irradiation the spin coated resists seem to need only a few bonds to be broken (low dose) in order to make the irradiated area insoluble in the developer solution. Ten-nm isolated resist lines and 15 nm lines etched into silicon were obtained with a spin-coatable 60 nm thick Al 2 O 3 resist layer [52]. The exposure was performed in a modified Hitachi HL-700F ebeam exposure system at 70 keV.…”