High-resolution laser direct writing with a plasmonic contact probe
Alternative Lithographic Technologies IV
We developed a contact-probe-based laser direct writing technique with nanometer scale resolution. The probe uses a solid-immersion-lens (SIL) or a bowtie nano-aperture to enhance the resolution in laser direct writing method and scans sample surface in contact mode for high scan speed. The bowtie shaped nano-aperture is fabricated by focused ion beam (FIB) milling on the metal film coated on cantilever type probe tip and dielectric material (Diamond-like carbon) is covered the probe for
... protection. Using a plasmonic contact probe, we obtained an optical spot beyond the diffraction limit and the size of spot was less than 30 nm at 405 nm wavelength. The proposed probe is integrated with a conventional laser direct writing system and by getting rid of external gap control unit for near-field writing, we achieved high scan speed (~10 mm/s). The raster scan mode for the arbitrary patterning was developed for practical applications. Furthermore, we designed developing a parallel maskless writing system for high throughput with an array of contact probes. Recently, the near-field optical lithography has been developed for high resolution optical patterning. Near-field scanning optical microscope lithography (NSOML) showed patterning resolution far beyond the diffraction limit. The surface-plasmon-assisted metal nano-aperture creates an extremely small spot at ridge gap [4-7]. Being exposed by the spot, the high resolution (~30 nm) arbitrary patterns can be recorded on the photoresist and the system proves the capability of nanofabrication based on the laser direct writing technique with high scan speed up to mm/s order by using of contact probe. In this paper, we developed a high resolution laser direct writing technique using SIL (a SIL-probe) and a nano-aperture (Nano-probe). The principles of the resolution enhancement and fabrication process are described. By showing the high resolution patterning results with high scan speed up to mm/s order, the system integrated with contact probes proves the capability as a nanofabrication tool.