Metal oxide multilayer hard mask system for 3D nanofabrication

Han, Zhongmei; Salmi, Emma; Vehkamäki, Marko; Leskelä, Markku; Ritala, Mikko

doi:10.1088/1361-6528/aa9fe0

Cited by 6 publications

(2 citation statements)

References 33 publications

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“…We have used this FIB‐milling‐wet etch procedure previously also for fabrication of various microstructures in combination with conventional, thermal ALD. [ 26 ]…”

Section: Resultsmentioning

confidence: 99%

Highly Material Selective and Self‐Aligned Photo‐assisted Atomic Layer Deposition of Copper on Oxide Materials

Miikkulainen

Vehkamäki

Mizohata³

et al. 2021

Adv Materials Inter

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There is a growing need for bottom‐up fabrication methods in microelectronic industry as top‐down, lithography‐based methods face increasing challenges. In Photo‐assisted atomic layer deposition (Photo‐ALD), photons supply energy to the deposition reactions on the surface. Here, a process and patterning for Photo‐ALD of copper is reported, with inherently selective, self‐aligned film growth without any photomasking or additive layers. Highly conductive and pure copper films are selectively deposited on tantalum oxide for over hundred nanometers of film thickness, while no copper deposits on silicon or aluminum oxide. On anatase titanium dioxide, copper deposition is crystal‐facet selective. Selective deposition of a metal is realized on oxides, which has been especially challenging for ALD. This study indicates that the growth mechanism is closely related to photocatalysis: the photons interact with the material under the growing copper film, enabling the inherent selectivity. The findings provide promising material engineering schemes for microelectronics, photocatalysis, and photovoltaics.

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“…We have used this FIB‐milling‐wet etch procedure previously also for fabrication of various microstructures in combination with conventional, thermal ALD. [ 26 ]…”

Section: Resultsmentioning

confidence: 99%

Highly Material Selective and Self‐Aligned Photo‐assisted Atomic Layer Deposition of Copper on Oxide Materials

Miikkulainen

Vehkamäki

Mizohata³

et al. 2021

Adv Materials Inter

Self Cite

View full text Add to dashboard Cite

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“…However, it is challenging work to build 3D wafer-level rectangular waveguides using thin-film processes and 2D (planar) technology. With micro/nano-fabrication technology, these fine 3D structures can be built easily [4][5][6]. Electrochemical fabrication (EFAB) and Polystrata processes were used to make 3D mm-wave devices via repeating the process of metal sacrificial layers multiple times [7,8].…”

Section: Introductionmentioning

confidence: 99%

Microfabrication of monolithic wafer-level miniaturized millimeter-wave air-filled half-mode waveguide filter based on the inward curving split ring resonator array

et al. 2020

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In this paper, we propose a miniaturized monolithic bandpass filter utilizing an air-filled halfmode waveguide and an inward curving split ring resonator array in the millimeter-wave band. The waveguide blocks the wave below cutoff frequency and the uniplanar array forms a rejection band above the transmission band. The microfabrication process of the filter adopts photoimageable technology and the combination of films with different thicknesses to build a 3D structure. The measured prototype has a center frequency at 65.5 GHz with a 3 dB fractional bandwidth of 30.7%. The minimum insertion loss is 2.1 dB. The proposed component offers excellent performance including a wide transmission band, a low pass-band insertion loss, an excellent isolation in the stop-band, and a steep roll-off at the upper cutoff frequency. Besides, due to the scalability of the waveguide and periodic array, this filter can be adapted for other frequency ranges.

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Additive Manufacturing of 3D‐Architected Multifunctional Metal Oxides

et al. 2019

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Additive manufacturing (AM) of complex three‐dimensional (3D) metal oxides at the micro‐ and nanoscales has attracted considerable attention in recent years. State‐of‐the‐art techniques that use slurry‐based or organic–inorganic photoresins are often hampered by challenges in resin preparation and synthesis, and/or by the limited resolution of patterned features. A facile process for fabricating 3D‐architected metal oxides via the use of an aqueous metal‐ion‐containing photoresin is presented. The efficacy of this process, which is termed photopolymer complex synthesis, is demonstrated by creating nanoarchitected zinc oxide (ZnO) architectures with feature sizes of 250 nm, by first patterning a zinc‐ion‐containing aqueous photoresin using two‐photon lithography and subsequently calcining them at 500 ºC. Transmission electron microscopy (TEM) analysis reveals their microstructure to be nanocrystalline ZnO with grain sizes of 5.1 ± 1.6 nm. In situ compression experiments conducted in a scanning electron microscope show an emergent electromechanical response: a 200 nm mechanical compression of an architected ZnO structure results in a voltage drop of 0.52 mV. This photopolymer complex synthesis provides a pathway to easily create arbitrarily shaped 3D metal oxides that could enable previously impossible devices and smart materials.

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Metal oxide multilayer hard mask system for 3D nanofabrication

Cited by 6 publications

References 33 publications

Highly Material Selective and Self‐Aligned Photo‐assisted Atomic Layer Deposition of Copper on Oxide Materials

Highly Material Selective and Self‐Aligned Photo‐assisted Atomic Layer Deposition of Copper on Oxide Materials

Microfabrication of monolithic wafer-level miniaturized millimeter-wave air-filled half-mode waveguide filter based on the inward curving split ring resonator array

Additive Manufacturing of 3D‐Architected Multifunctional Metal Oxides

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