Metallized photoresists: A new approach to surface imaging

Mihov

Advances in Resist Technology and Processing XX

et al. 2003

Focused Ion beam (FIB) lithography has significant advantages over the electron beam counterpart in terms of resist sensitivity, backscattering and proximity effects. However, combining the FIB lithography with Top Surface Imaging (TSI) will extend its advantages by allowing anisotropic processing of thicker resist layers. This paper reports the development of novel single layer lithography process by combining focused Ga + ion beam (Ga + FIB) lithography, silylation and oxygen dry etching. The Negative Resist Image by Dry Etching (NERIME) is a TSI scheme for DNQ/novolak based resists and can result in either positive or negative resist images depending on the extent of the ion beam exposure dose. Results show that Ga + ion beam dose in the range of 1µC/cm 2 to 50µC/cm 2 at 30keV can successfully prevent silylation of the resist, thus resulting in the formation of positive image after the dry etching. A negative image can be formed by using a second Ga + ion beam exposure with a dose higher than 900µC/cm 2 at 30keV to pattern lines into the original exposed resist area. It was observed that resist regions exposed to such high doses can effectively withstand oxygen dry development, thus giving formation of negative resist image. In this study, nanometer resist patterns with high aspect ratio up to 15 were successfully resolved due to the ion beam exposure and anisotropic dry development. This novel TSI scheme for ion beam lithography could be utilized for the fabrication of critical CMOS process steps, such as deep isolation trench formation and lithography over substantial topography.

Section: The Effect Of Ga + Ion Beam Exposure Dose On the Dry Developmentioning

confidence: 98%

Negative resist image by dry etching as a novel top surface imaging process for ion-beam lithography

Mihov

Advances in Resist Technology and Processing XX

et al. 2003

“…Melngailis [1] also reported that Ga + implantation in spin-on glass substrates can reduce the oxygen plasma etch rate by 30%. Moreover, Abali et al [22] have found that novolak resist which had a 7-17nm surface covering of Ni exhibited extremely small etch rates under oxygen plasma development. The experiments carried out in this work using high dose Ga + ion implantation in novolak based resists indicate the same etching behavior.…”

Section: 1mentioning

confidence: 98%

Two-step modified NERIME process using combined focused ion beam lithography and plasma etching

et al. 2003

Focused ion beams (FIB) have been widely used as a patterning lithography technique for advanced ICs and optical masks fabrication. FIB lithography has certain advantages over the direct-write electron beam lithography in terms of resist sensitivity, backscattering and proximity effects. However, combining the FIB exposure with both Top Surface Imaging (TSI) and dry etching will further extend its advantages towards anisotropic processing of thicker resist layers in comparison to those used by the conventional lithography processes. The newly developed NERIME (Negative Resist Image by Dry Etching) process combines these advantages by the incorporation of focused Ga + ion beam (Ga + FIB) exposure, near UV exposure, silylation and dry etching. The work described here follows our investigations into the NERIME process for nanostructure applications and outlines a simplified (two-step) process incorporating FIB exposure and oxygen dry development. The two-step modified NERIME process is a negative working TSI system for DNQ/novolak based resists. Results show that Ga + ion beam dose higher than 800µC/cm 2 at 30keV can modify the exposed resist areas as to withstand the subsequent oxygen plasma etching, thus giving formation of negative resist image. In this study, nanometer resist patterns as small as 30nm with high aspect ratio of up to 15 were successfully resolved due to the high resolution ion beam exposure and anisotropic dry development. The proposed two-step lithography scheme could be utilized for the fabrication of critical CMOS process steps, such as sub-100nm gate formations and lithography over substantial topography.

Trans. Mat. Res. Soc. Japan

“…[1][2][3] Photolithography techniques using deep UV light and electron beams enable the fabrication of metal patterns at several tens of nanometer scale. [4,5] Scanning probe lithography is also used for the nanopatterning of metal thin films.…”

Section: Introductionmentioning

confidence: 99%

Patterning of Cu thin films on layer-by-layer films of anionic polymer and TiO<sub>2</sub> nanoparticles on plastic sheets

Watanabe

Morimoto

Yanagida

et al. 2014

We report a technique of direct patterning of Cu thin films on Pd nanoparticles photodeposited on layer-by-layer (LbL) films consisting of sodium polystyrene sulfonate (PSS) and TiO 2 nanoparticles on plastic sheets. The LbL films were formed on plastic sheets by soaking the plastic sheets alternately in PSS acidic solution and TiO 2 nanoparticle dispersion. The amounts of PSS and TiO 2 nanoparticles in the LbL films were proportional to the number of immersion. Pd nanoparticles were formed on the PSS/TiO 2 LbL films by irradiation with UV light through metal masks in acidic solution of palladium chloride. The amount of the Pd nanoparticles increased with increasing UV irradiation time. Cu films were deposited selectively on the Pd nanoparticles in the electroless plating bath of Cu. The results of the energy dispersive X-ray analysis and the elemental mapping were consistent with the above results. With an increase in the layer number of the LbL films, the growth rate of Cu films increased probably due to an increase in the amount of Pd nanoparticles on the LbL films. This technique allows for the reduced material consumption and fabrication steps in direct metal patterning on plastic sheets using light irradiation.