Patterning of self-assembled monolayers with lateral dimensions of 0.15 mum using advanced lithography

The use of advanced lithography to pattern self-assembled monolayers (SAMs) was investigated as a means to create surfaces with regions of different c hemical functionality with dimensions of order 0.10 mu m. SAMs were prepare d by the chemisorption of octadecyltrichlorosilane on silicon wafers, and e xposed to synchrotron x-ray (0.814 nm) radiation or extreme ultraviolet (EU V, 13.4 nm) radiation. Exposure to x rays in the presence of oxygen resulte d in the incorporation of hydroxy (C-OH) and aldehyde (CH=O) functional gro ups on the SAM surfaces. The extent of chemical modification was a function of exposure dose and air pressure. Patterned SAMs with various shapes at s cales from 50 mu m to 0.15 mu m were obtained by exposing SAMs to x rays th rough a mask, or with interferometric EUV lithography. The SAM patterns wer e imaged directly by condensation figures and lateral force microscopy, and were imaged indirectly using atomic force microscopy and the topography of thin films of diblock copolymers. The contrast in the indirect method resu lted from a difference in film thickness due to different wetting behavior of thin films of diblock copolymers on the patterned surfaces. (C) 1999 Ame rican Vacuum Society. [S0734-211X(99)06306-4].