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Deformation of the pattern or the increase in line roughness during plasma etching becomes more significant with the shrink of complementary metal–oxide–semiconductor patterns. For aggressively scaled patternings, an organic underlayer (UL) is often used under the photoresist and a thin layer of a Si-containing hardmask. In this work, the effect of ultraviolet/vacuum ultraviolet (VUV) photons on UL parameters such as wavelength, photon dose, and process order was investigated using synchrotron radiation. First, the index of refraction and extinction coefficients of mask materials such as e-beam resist [hydrogen silsesquioxane (HSQ)] and organic UL (NFC-1400; NFC) were measured by utilizing the Kramers–Kronig relations and/or ellipsometry measurements depending on the wavelength involved. Second, VUV photons at specific wavelengths, corresponding to absorption maxima of HSQ and NFC at 54 nm (HSQ), 62 nm (HSQ and NFC), 88 nm (HSQ), 112 nm (NFC), 138 nm (HSQ), 155 nm (NFC), 194 nm (NFC), and 238 nm (NFC), we...

The ability to achieve atomic layer precision is the utmost goal in the implementation of atomic layer etch technology. Carbon-based materials such as carbon nanotubes (CNTs) and graphene are single atomic layers of carbon with unique properties and, as such, represent the ultimate candidates to study the ability to process with atomic layer precision and assess impact of plasma damage to atomic layer materials. In this work, the authors use these materials to evaluate the atomic layer processing capabilities of electron beam generated plasmas. First, the authors evaluate damage to semiconducting CNTs when exposed to beam-generated plasmas and compare these results against the results using typical plasma used in semiconductor processing. The authors find that the beam generated plasma resulted in significantly lower current degradation in comparison to typical plasmas. Next, the authors evaluated the use of electron beam generated plasmas to process graphene-based devices by functionalizing graphene with...

With increasing demands on device patterning to achieve smaller critical dimensions and pitches for the 5 nm node and beyond, the need for atomic layer etching (ALE) is steadily increasing. In this work, a cyclic fluorocarbon/Ar plasma is successfully used for ALE patterning in a manufacturing scale reactor. Self-limited etching of silicon oxide is observed. The impact of various process parameters on the etch performance is established. The substrate temperature has been shown to play an especially significant role, with lower temperatures leading to higher selectivity and lower etch rates, but worse pattern fidelity. The cyclic ALE approach established with this work is shown to have great potential for small scale device patterning, showing self-limited etching, improved uniformity and resist mask performance.