| Description |
Thermal scanning probe lithography (t-SPL) has recently entered the lithography market as first true alternative to electron beam lithography (EBL). By now, the first dedicated t-SPL systems, called NanoFrazor, have been installed at research facilities in Europe, America, Asia and Australia by the company SwissLitho, a spinoff company of ETH Zurich.
Core of the technology - which has its origins at IBM Research and their Millipede project - is a heatable probe tip (Figure 1a) which is used for patterning and simultaneous inspection of complex nanostructures [1, 2]. The heated tip creates arbitrary high-resolution (<10 nm half-pitch) nanostructures by local decomposition and evaporation of resist materials. The patterning depth can be controlled with 1 nm accuracy, enabling patterning of 3D nanostructures in a single step.
The patterning speed of t-SPL is comparable to that of high-resolution Gaussian shaped EBL, and a scan speed of 20 mm/s with a pixel rate of 500 kHz has been demonstrated [3]. The written nanostructures are inspected by the cold tip in parallel with the patterning process. This high speed online metrology capability enables turnaround times of seconds and significantly improves accuracy and reliability. Furthermore, new stitching [4] and overlay [5,6] methods have been developed that achieve sub-5 nm accuracy without the use of artificial marker structures.
Various pattern transfer methods based on reactive ion etching [7], lift-off [8], electroplating, directed self-assembly [9] and more have been demonstrated in combination with t-SPL. For example, parallel lines with 18.5 nm half-pitch have been etched 65 nm deep into Si (Figure 1b) and various high resolution metal structures have been fabricated using lift-off or etching (Figure 1c). The t-SPL process does not use high energy charged particles like electrons or ions, which are known to damage or charge up certain materials during patterning. For delicate nanoelectronic devices this can result in superior device performance. For example, top gates for an InAs nanowire device have been fabricated without trapped charge in the thin gate oxide under the electrodes (Figure 1d). The patterning of accurate 3D structures enables nanooptical components, like blazed gratings or spiral phase plates (Figure 1e). The reasonable patterning speed and automation of the system allows the realization of macroscopic structures with nanoscale resolution (Figure 1f).
Bio
Felix Holzner studied physics in New Zealand and Germany and received a PhD from ETH Zurich.
In 2009, he joined the Nanofabrication Group at the IBM Research Laboratory in Zurich where he started to work on Thermal Scanning Probe Lithography. After several technological breakthroughs, Felix shortened the name of the technology to “NanoFrazor” and founded SwissLitho in 2012 with the clear vision to enable superior nanofabrication for everyone. He strongly believes that the unique capabilities of the NanoFrazor enable new science and eventually even products not conceivable today.
Felix has a complete overview over all possible nanolithography technologies and a very deep understanding of the NanoFrazor technology and its applications. He is a regular invited speaker at international conferences.
Felix received the IBM Plateau Invention Achievement Award and the ETH Pioneer Fellowship in 2012 and 2013, respectively. With SwissLitho and the NanoFrazor, he won numerous of the most prestigious startup and technology awards exceeding prize money of 500’000 CHF. In 2013, he was part of the Swiss national startup team in the ventureleaders program in Boston and recently received a scholarship for the Advanced Management Program at the University of St. Gallen (HSG).
Felix lives his vision and leads SwissLitho as CEO.
Bibliography:
[1] Pires et al., Science, 238, 732-735, (2010)
[2] Knoll et al., Advanced Materials, 22, 31, (2010)
[3] Paul et al., Nanotechnology, 22, 275-306, (2011)
[4] Paul et al., Nanotechnology, 23, 385307, (2012)
[5] Rawlings et al., IEEE Transactions on Nanotechnology, 13, 6, 1204–1212, (2014)
[6] Rawlings et al., ACS Nano, 9, 6188-6195, (2015)
[7] Holzner et al., Appl. Phys. Lett., 99, 023110, (2011)
[8] Wolf et al., JVSTB, 33, 2, 02B102, (2015)
[9] Holzner et al., Nano Letters, 11, 3957–3962, (2011)
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