ION-BEAM MODIFICATION AND PATTERNING OF ORGANOSILANE SELF-ASSEMBLED MONOLAYERS

The patterning and modification of organosilane self-assembled monolay ers on Si native oxide surfaces by low- and high-energy ion beams were investigated. The nature and extent of low-energy (50-140 eV) Ar+ ion -induced modification of a 2-(trimethoxysilyl) ethyl-2-pyridine monola yer was studied by x-ray photoelectron spectroscopy and by the quality of the electroless Ni patterns obtained. C(1s) and N(1s) core level x -ray photoelectron spectroscopy indicated that the ion-induced modific ation of the monolayer involved loss of the ethylpyridyl chain by sput tering and/or decomposition. The type of modification was independent of the ion energy and fluence, but the extent of modification depended on both parameters. The modification of the pyridine monolayer was mo nitored by the percent loss in the N(1s) peak area; modification comme nced at a fluence of 5x10(14) ions/cm(2) and was observed for all ion energies studied. However, selective electroless metallization occurre d only for monolayers that suffered >50% loss in the N(1s) x-ray photo electron spectroscopy signal. A damage saturation level of 80% N(1s) l oss was indicated at an ion fluence of 9 X10(15) ions/cm(2). A high-en ergy focused ion beam lithography system was also used to evaluate the high resolution patterning of N-(2-aminoethyl)-3-aminopropyltrimethox ysilane, (aminoethylaminomethyl)phenethyltrimethoxysilane, and pyridin e monolayers by Ga+, Si++, Au+ and Au++ ions at energies ranging from 50 to 280 keV. The highest resolution metal features obtained were 0.3 -mu m-wide gaps on phenethyltrimethoxysilane and pyridine monolayers u sing Ga+ and Si++ ions. Aminopropyltrimethoxysilane monolayers were fo und to require ten times higher ion fluences to achieve comparable res ults with the phenethyltrimethoxysilane and pyridine monolayers for al l ions investigated. (C) 1995 American Vacuum Society.