Photoresist Polymer Mask Formed From Aqueous Phase Via Polymerization In A Two Dimensional Surfactant Template

Abstract

An environmental friendly, aqueous based, thin film technology is investigated that is quite versatile in forming a variety of polymer substrates. The polymer substrates are potentially capable of being utilized as high resolution resists for semiconductor chip production. This process is based on polymerization of monomers partitioned within a two dimensional surfactant template adsorbed on the surface of a silicon wafer. The surfactant template (bilayer) serves to localize the polymerization reaction at the liquid‐solid interface and thereby resulting in the coverage of the silicon wafer with a nano‐thin polymer film. On a polished silicon wafer with a 4 nm silicon oxide layer, film thickness up to 130 nm have been obtained for polystyrene and for poly(methyl methacrylate) (PMMA) which is also used as a standard photoresist mask in electron beam lithography.

Two-dimensional phase transition of styrene adsolubilized in cetyltrimethylammonium bromide admicelles on mica

“…Adsorbed aggregates (admicelles), whether discrete or continuous, possess some properties which are similar to those of micelles including the ability of adsolubilizing sparingly soluble/insoluble compounds in aqueous solutions [1]. Applications of adsolubilization include concentrating and removing selected organic constituents in environmental remediation [2], analyzing mixtures of optical isomers in admicellar chromatography [3], concentration of organic reactants in admicellar catalysis [4] and modification of surfaces by polymerization of monomers within admicelles, a process called admicellar polymerization [5][6][7].…”

“…The structure of the formed polymer thin film has been examined using ellipsometry [5], scanning electron microscopy [17], and tapping mode atomic force microscope at ambient condition [18,19]. However, without an understanding of the behavior of the multicomponent adsorbed layer, the structure and properties of the formed polymer film cannot be predicted or effectively controlled [20].…”

“…The droplet sizes fall into two ranges, 100-200 nm and ≈20 nm. These droplets are thought to be responsible for the irregular patchy polymer film found after admicellar polymerization[4][5][6][7][18][19][20][21][22][23].…”