AFM Anodization Lithography on Positively Charged Metal Phosphonate Monolayers

Sang Min Kim, Seung Hyun Lee, Sang Jung Ahn, Heaseong Lee, Eung Ryul Kim, and Haiwon Lee

Department of Chemistry, Hanyang University, Seoul, 133-791, Korea

Monolayer films of metal phosphonate were prepared by sequential adsorption of phosphonic acid (PA) and metal ions (Zr⁴⁺ or Ca²⁺). First, a monolayer of PA was self-assembled on silicon substrate, and then the PA/Si substrate was dipped into a solution of Zr⁴⁺ ions or Ca²⁺ ions to bind a metal ion. Nano-scale patterning on the self-assembled metal phosphonate films has been achieved using an atomic force microscope (AFM). The difference in AFM lithography on positively charged surfaces in case of Zr⁴⁺ and Ca²⁺ was investigated and summarized. The lithographic results on metal phosphonate layers will be compared with those on organic layers. This study will enable us to develop better resists for AFM anodization lithography.