Scanning probe lithography on calixarene towards single-digit nanometer fabrication

Key words: 
• nanofabrication /
• field-emission scanning probe lithography /
• single nanometer lithography /
• molecular resist

Abstract: 

Cost effective patterning based on scanning probe nanolithography (SPL) has the potential for electronic and optical nano-device manufacturing and other nanotechnological applications. One of the fundamental advantages of SPL is its capability for patterning and imaging employing the same probe. This is achieved with self-sensing and self-actuating cantilevers, also known as 'active' cantilevers. Here we used active cantilevers to demonstrate a novel path towards single digit nanoscale patterning by employing a low energy (<100 eV) electron exposure to thin films of molecular resist. By tuning the electron energies to the lithographically relevant chemical resist transformations, the interaction volumes can be highly localized. This method allows for greater control over spatially confined lithography and enhances sensitivity. We found that at low electron energies, the exposure in ambient conditions required approximately 10 electrons per single calixarene molecule to induce a crosslinking event. The sensitivity was 80-times greater than a classical electron beam exposure at 30 keV. By operating the electro-exposure process in ambient conditions a novel lithographic reaction scheme based on a direct ablation of resist material (positive tone) is presented.