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Articles you may be interested inDry-etching properties of TiN for metal/high-k gate stack using B Cl 3 -based inductively coupled plasmaa) Evaluation of silicon oxide cleaning using F 2 ∕Ar remote plasma processing J. Vac. Sci. Technol. A 23, 911 (2005); 10.1116/1.1885018Transformer coupled plasma etching of 3C-SiC films using fluorinated chemistry for microelectromechanical systems applicationsFor the fabrication of microelectromechanical system devices, deep trench etching of borosilicate glass ͑Corning 7740͒ has been investigated using SF 6 /Ar inductively coupled plasma. Since borosilicate glass contains metal elements which produce nonvolatile fluorides, dry etching of its smooth surface is a difficult issue. In this article, requisite conditions for etching glass with a smooth surface and high mask selectivity have been discussed on the basis of the results of a comprehensive experimental study of the effects of substrate bias power and Ar addition on the removal of involatile fluoride residues deposited via the backscattering of etch products in the vicinity of the substrate surface. Under optimized etching conditions, deep trench etching of borosilicate glass to 32 m depth and 15 m width has been accomplished using 3-m-thick chrome metal masks.

To maintain the silica surface of imprint templates without a fluorine-containing passivation layer on sidewalls after dry etching, we investigated whether a physical dry etching process entailing exposure to Ar ion beam is useful for the fabrication of silica templates. An almost same etching rate of a positive-tone electron beam (EB) resist as silica in Ar ion beam milling allowed for the fabrication of bar-shaped patterns with micrometer lengths and widths for moiré alignment and of hole patterns with diameters of around 20 nm in silica templates. The EB resist layer of 40 nm thickness generated partially non-etched defects of 10-nm-diameter holes in silica templates because the Ar ion beam was completely unable to reach silica surfaces through resist sidewalls with a depth of 40 nm. The break-through etching of a hard mask sacrifice Cr layer with a thickness of 5 nm by Ar ion milling and the subsequent inductively coupled plasma etching of silica enabled the fabrication of silica hole templates with diameters of 7–20 nm and depths of 20–30 nm.

Oxygen ion beam irradiation of glassy carbon (GC) surface is used to fabricate anti-reflection (AR) structures. Ion beam energy of 500 eV has been used to fabricate the finest pitch of AR structures in an irradiation time of 24 min or more. It has been used to fabricate conical AR structures of more than 250 nm in height, and has non-reflective (less than 0.1% reflection) property over the range of visible light. Furthermore, with this method, oblique incident angle reflection has been suppressed. This method is very simple. However, fabrication of AR structures with high throughput is needed, that is now considered achievable.

Glass is a good candidate material for optical devices because of its enhanced optical properties, the technique of die machining has not been established for the hot embossing of glass. In this study, we used the glassy carbon (GC) mold for the hot embossing of glass. An inductively coupled plasma reactive ion etching (ICP-RIE) using oxygen plasma was employed for the submicron structuring of the GC mold. Hydrogen silsesquioxane (HSQ) is a negative-type electron beam (EB) resist used to be resistant to oxygen plasma. HSQ patterns drawn by electron beam lithography (EBL) were used as the O 2 dry etching mask. The etching selectivity between HSQ and GC was 35. The average of the extent of side etching was 40 nm at a depth of 300 nm. The side etching functioning as the draft angle was caused mainly by oxygen radicals, because HSQ patterns remained even after GC patterns were side-etched. We confirmed that the GC mold fabricated by O 2 dry etching can be used for glass hot embossing. Since the mold lubricant was not rubbed on the mold surface, GC is the appropriate mold material for Pyrex glass.