Ion projection microlithography for submicron device fabrication

Stengl, G.; Kaitna, R.; Löschner, H.; Rieder, R.; Wolf, Peter; Sacher, Robert E.

doi:10.1116/1.571235

Cited by 12 publications

(7 citation statements)

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“…Their liquidus data combined with ideal solution model for both solid and liquid phases resulted in pseudobinary phase diagram. Laugier (4) obtained solid solution parameter ~ = 1340 cal assuming ideal liquid and regular solid solution by fitting experimental data of Steininger et al (3). His phase diagram differed slightly from that of Steininger et al, but in both cases agreement with experimental data was satisfactory.…”

Section: Institute For Metal Research Polish Academy Of Sciences 30mentioning

confidence: 80%

“…Gromakov et al (2) have performed thermal analysis study to determine ZnTe-CdTe phase diagram, but their results were more than 40 K lower than the most recent data, even for pure compounds. Steininger et al (3) have carried out extensive studies on ternary Zn-Cd-Te and pseudobinary ZnTeCdTe systems by means of thermal analysis. Their liquidus data combined with ideal solution model for both solid and liquid phases resulted in pseudobinary phase diagram.…”

Section: Institute For Metal Research Polish Academy Of Sciences 30mentioning

confidence: 99%

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Ion Beam Exposure of Polymer Resist PMMA

Tung¹

1984

J. Electrochem. Soc.

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Ion beam exposure characteristics of a positive polymer resist, polymethylmetacrylate (PMMA) have been investigated. The samples were irradiated with B § ions in the energy range of 20-160 keV, the ion dose varying between 8 x 10" and 5 • 10 '3 cm -2. In the energy range considered, beam sensitivity and resist contrast were found to be between 4-5 • 10 '2 cm --~ and 2.3-2.5, respectively. An empirical formula is proposed to approximate the characteristic dissolutiOn curves (thickness removed vs. dissolution time). The empirical values agree with the experimental results within an accuracy better than 12%. A procedure is described whereby the total number of scission chain fragments as a function of resist depth may be extracted from the experimental curves.Ion beam lithography is a novel technique which bypasses some of the drawbacl}s of electron beam lithography. In general, resists are more sensitive to ions than to electrons. This is due to a greater energy deposition per unit volume. Another advantage in ion beam lithography is its feeble lateral spread (100k) for heavy ions. Ion beams, as compared to electron beams, produce low energy electrons and negligible amount of high energy backscattered electrons. In the case of direct writing using an ion beam, pattern dimensions are limited only by the beam size. Indeed, pattern dimensions inferior to 1000~ (1, 2) have been obtained with a liquid-metal gallium ion source.Ion lithography can be carried out in two different ways: through direct writing and through the ion projection exposure technique as developed by Sacher Technik Wien (3). A liquid metal ion source (4-8) can be used for direct writing, as in electron beam lithograpy, but with reduced computing time owing to the absence of proximity effects and enhanced ion sensitivity. Another method of transferring patterns to resists is through direct contact masking of the resist; channeling (9) may also be used; typical mask to resist distances are 20 ~m.Komuro et al. (10) have investigated the ion beam sensitivity of positive PMMA and negative PDMS (polydimethylsiloxane) using He + ions (60-and 200 keV) and Ar ~ ions (150 and 250 keV). According to their measurements, the calculated Gel and Gn values are 1.7 and 0.9, respectively, for PMMA whose average molecular weight is 1.85 x 105. Gel and Gn are the radiation yields per 100 eV absorbed for main chain scission brought about by electronic and nuclear collisions, respectively. Hall et al. (11) have studied the behavior of positive and negative resists using high energy ions: hydrogen, helium, and oxygen at 1.5 MeV. They proposed a model to account for the variation of the energy distribution around the particle track in terms of the number of sites required for exposure. Ryssel et al. (12) presented the dissolution characteristics of both positive and negative resists exposed to argon, gallium, hydrogen, and helium ions.Karapiperis et al. (13) have used Monte Carlo computer simulations to calculate the electronic and nuclear energy losses of 60 keV H + ions i...

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Section: Institute For Metal Research Polish Academy Of Sciences 30mentioning

confidence: 80%

Section: Institute For Metal Research Polish Academy Of Sciences 30mentioning

confidence: 99%

Ion Beam Exposure of Polymer Resist PMMA

Tung¹

1984

J. Electrochem. Soc.

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“…In the past the major application of bombardment-enhanced etching has not been the patterning of films, but the fabrication of tapered windows for contact holes in SiO2 (8)(9)(10)(11). More recently, however, there has been a renewed interest in the use of bombardment-enhanced etching in combination with ion beam lithography (12,13). By combining these two techniques, dielectric or semicondueting films can be patterned directly, i.e., without an additional layer of photoresist.…”

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confidence: 99%

Etch Rate Modification of Si3 N 4 Layers by Ion Bombardment and Annealing

Ommen

Willemsen

Kuiper

et al. 1986

J. Electrochem. Soc.

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Damage induced by ion bombardment normally increases the etch rate of materials, including Si3N4 . Upon annealing, this effect in general disappears. This paper presents a different behavior found in the etch properties of Si3N4 layers deposited by a chemical vapor deposition process at reduced pressures. Annealing of these films at temperatures below 750°C results in the normal decreasing difference in etch rate between implanted and unimplanted nitride due to the elimination of implantation damage. However, upon annealing above this temperature of 750°C the etch rate of implanted nitride becomes “lower” than that of unimplanted nitride. This effect has been investigated as a function of implantation, annealing, and etching conditions. A model is presented in which the effect is explained in terms of hydrogen that is incorporated in these films during the chemical vapor deposition process. Finally, the applicability of the effect in semiconductor technology is discussed, especially for the fabrication of submicron features.

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“…L'utilisation de masques « à trous » pose un problème « topologique », pour la duplication de formes du type « anneau (surfaces fermées). De nombreuses solutions sont possibles pour maintenir en place la partie qui n'est pas connectée avec le reste du masque : par exemple [2], un système avec réduction d'échelle (x 1/10) permettant de faire supporter le masque (de dimensions minimales de l'ordre de quelques microns) par une grille (submicronique) de dimensions inférieures à la résolution de l'optique ionique. Il est ainsi possible d'obtenir des motifs submicroniques avec disparition de la grille dans la résine.…”

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“…On discutera les avantages et inconvénients respectifs de chaque espèce d'ion, en relation avec leur disponibilité pratique. Des résultats expérimentaux de reproduction de motifs submicroniques dans la résine à partir de masques adaptés seront présentés 2…”

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