Dendrimer Monolayers as Negative and Positive Tone Resists for Scanning Probe Lithography

A new scanning probe lithography scheme based on a self-assembled dendrimer monolayer on thin Ti films is presented. The method relies on the versatility of the functionalized dendrimer molecules to effectively function as etch resists by forming a densely packed self-assembled protective monolayer on a Ti film. Patterning of the Ti surface is accomplished using an AFM tip either as an ultra sharp scribe or as an electrical field point source to modify the monolayer. This, coupled to carefully selected etching conditions, allows the use of the dendrimer monolayers as both negative and positive tone resists. Facile formation of TiO2 features ca. 25 nm wide and 12 nm tall on silicon oxide and ca. 50 nm wide gaps in a thin Ti film can easily be achieved. The dendrimer resist approach can be further developed in order to improve the minimum feature size to the single dendrimer molecule level.