Electron-beam lithography

About: Electron-beam lithography is a research topic. Over the lifetime, 8982 publications have been published within this topic receiving 143325 citations. The topic is also known as: e-beam lithography.

Controlling Plasmon Line Shapes through Diffractive Coupling in Linear Arrays of Cylindrical Nanoparticles Fabricated by Electron Beam Lithography

Abstract: The effect of diffractive coupling on the collective plasmon line shape of linear arrays of Ag nanoparticles fabricated by electron beam lithography has been investigated using Rayleigh scattering spectroscopy. The array spectra exhibit an intricate multi-peak structure, including a narrow mode that gains strength for interparticle distances that are close to the single particle resonance wavelength. A version of the discrete dipole approximation method provides an excellent qualitative description of the observed behavior.

Broadband antireflection gratings fabricated upon silicon substrates.

Abstract: We fabricated a two-dimensional subwavelength structured (SWS) surface upon a crystal silicon substrate. The SWS surface was patterned by electron beam lithography and etched by an SF(6) fast atom beam. The SWS grating had a conical profile, the period was 150 nm, and the groove was approximately 350 nm deep. The reflectivity was examined at 2002500-nm wavelengths. At 400 nm the reflectivity decreased to 0.5% from the 54.7% of the silicon substrate. We also used HeNe laser light to examine the reflectivity as a function of the incident angle.

Three-dimensional deep sub-diffraction optical beam lithography with 9 nm feature size

Abstract: The current nanofabrication techniques including electron beam lithography provide fabrication resolution in the nanometre range. The major limitation of these techniques is their incapability of arbitrary three-dimensional nanofabrication. This has stimulated the rapid development of far-field three-dimensional optical beam lithography where a laser beam is focused for maskless direct writing. However, the diffraction nature of light is a barrier for achieving nanometre feature and resolution in optical beam lithography. Here we report on three-dimensional optical beam lithography with 9 nm feature size and 52 nm two-line resolution in a newly developed two-photon absorption resin with high mechanical strength. The revealed dependence of the feature size and the two-line resolution confirms that they can reach deep sub-diffraction scale but are limited by the mechanical strength of the new resin. Our result has paved the way towards portable three-dimensional maskless laser direct writing with resolution fully comparable to electron beam lithography.

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

Abstract: 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.

Lithography and Other Patterning Techniques for Future Electronics

Abstract: For all technologies, from flint arrowheads to DNA microarrays, patterning the functional material is crucial. For semiconductor integrated circuits (ICs), it is even more critical than for most technologies because enormous benefits accrue to going smaller, notably higher speed and much less energy consumed per computing function. The consensus is that ICs will continue to be manufactured until at least the ldquo22 nm noderdquo (the linewidth of an equal line-space pattern). Most patterning of ICs takes place on the wafer in two steps: (a) lithography, the patterning of a resist film on top of the functional material; and (b) transferring the resist pattern into the functional material, usually by etching. Here we concentrate on lithography. Optics has continued to be the chosen lithographic route despite its continually forecast demise. A combination of 193-nm radiation, immersion optics, and computer-intensive resolution enhancement technology will probably be used for the 45- and 32-nm nodes. Optical lithography usually requires that we first make a mask and then project the mask pattern onto a resist-coated wafer. Making a qualified mask, although originally dismissed as a ldquosupport technology,rdquo now represents a significant fraction of the total cost of patterning an IC largely because of the measures needed to push resolution so far beyond the normal limit of optical resolution. Thus, although optics has demonstrated features well below 22 nm, it is not clear that optics will be the most economical in this range; nanometer-scale mechanical printing is a strong contender, extreme ultraviolet is still the official front runner, and electron beam lithography, which has demonstrated minimum features less than 10 nm wide, continues to be developed both for mask making and for directly writing on the wafer (also known as ldquomaskless lithographyrdquo). Going from laboratory demonstration to manufacturing technology is enormously expensive ( $1 billion) and for good reason. Just in terms of data rate (mask pattern to resist pattern), today's exposure tools achieve about 10 Tb/s at an allowable error rate of about 1/h; this data rate will double with each generation. In addition, the edge placement precision required will soon be 30 parts per billion. There are so many opportunities for unacceptable performance that making the right decision goes far beyond understanding the underlying physical principles. But the benefits of continuing to be able to manufacture electronics at the 22-nm node and beyond appear to justify the investment, and there is no shortage of ideas on how to accomplish this.