10nm lines and spaces written in HSQ, using electron beam lithography

Grigorescu, Anda E.; Krogt, Marco C. van der; Hagen, C. W.; Kruit, P.

doi:10.1016/j.mee.2007.01.022

Cited by 96 publications

(61 citation statements)

References 10 publications

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“…However for ultrathin HSQ layers, the last one seems to be the only drawback. Word et al [60] showed that very thin HSQ (25-100 nm) layers have a low roughness and are defect free, as shown in figure 19.…”

Section: Spin Coating Of Resistmentioning

confidence: 99%

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

2009

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In the past decade, the feature size in ultra large-scale integration (ULSI) has been continuously decreasing, leading to nanostructure fabrication. Nowadays, various lithographic techniques ranging from conventional methods (e.g. photolithography, x-rays) to unconventional ones (e.g. nanoimprint lithography, self-assembled monolayers) are used to create small features. Among all these, resist-based electron beam lithography (EBL) seems to be the most suitable technique when nanostructures are desired. The achievement of sub-20-nm structures using EBL is a very sensitive process determined by various factors, starting with the choice of resist material and ending with the development process. After a short introduction to nanolithography, a framework for the nanofabrication process is presented. To obtain finer patterns, improvements of the material properties of the resist are very important. The present review gives an overview of the best resolution obtained with several types of both organic and inorganic resists. For each resist, the advantages and disadvantages are presented. Although very small features (2-5 nm) have been obtained with PMMA and inorganic metal halides, for the former resist the low etch resistance and instability of the pattern, and for the latter the delicate handling of the samples and the difficulties encountered in the spinning session, prevent the wider use of these e-beam resists in nanostructure fabrication. A relatively new e-beam resist, hydrogen silsesquioxane (HSQ), is very suitable when aiming for sub-20-nm resolution. The changes that this resist undergoes before, during and after electron beam exposure are discussed and the influence of various parameters (e.g. pre-baking, exposure dose, writing strategy, development process) on the resolution is presented. In general, high resolution can be obtained using ultrathin resist layers and when the exposure is performed at high acceleration voltages. Usually, one of the properties of the resist material is improved to the detriment of another. It has been demonstrated that aging, baking at low temperature, immediate exposure after spin coating, the use of a weak developer and development at a low temperature increase the sensitivity but decrease the contrast. The surface roughness is more pronounced at low exposure doses (high sensitivity) and high baking temperatures. A delay between exposure and development seems to increase both contrast and the sensitivity of samples which are stored in a vacuum after exposure, compared to those stored in air. Due to its relative novelty, the capabilities of HSQ have not been completely explored, hence there is still room for improvement.Applications of this electron beam resist in lithographic techniques other than EBL are also discussed. Finally, conclusions and an outlook are presented.

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Section: Spin Coating Of Resistmentioning

confidence: 99%

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

2009

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“…Electron-beam lithography (EBL) at energies 30 keV and above is a well established method of fabricating sub-20-nm-pitch structures [1,2,3,4]. However, EBL at these high energies suffers from long-range proximity effects.…”

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confidence: 99%

Sub-5keV electron-beam lithography in hydrogen silsesquioxane resist

Manfrinato

Cheong

Duan

et al. 2011

Microelectronic Engineering

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Abstract:We fabricated 9 to 30 nm half-pitch nested Ls and 13 to 15 nm half-pitch dot arrays, using 2 keV electron-beam lithography with hydrogen silsesquioxane (HSQ) as the resist. All structures with 15 nm half-pitch and above were fully resolved. We observed that the 9 and 10-nm half-pitch nested L's and the 13-nm-half-pitch dot array contained some resist residues. We obtained good agreement between experimental and Monte-Carlo-simulated point-spread functions at energies of 1.5, 2, and 3 keV. The longrange proximity effect was minimal, as indicated by simulated and patterned 30 nm holes in negative-tone resist.

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“…The contrast and line-wall roughness (line-wide fluctuations) are much lower than the contrast in traditional chain scission PMMA due to the oligomer nature of HSQ. In the references (Namatsu et al, 1998;Grigorescu et al, 2007) the resolution of sub-20 nm features has been also shown. Table 6 Fig.…”

Section: Inorganic Ebl Nanoresistsmentioning

confidence: 99%