Dr. Helmut Schift

Polymer Nanotechnology is aiming to provide solutions for different applications of polymer surfaces, by modifying surfaces by patterning, exposure, thermal treatment and coating. Current examples are supersmooth surfaces for micro-optics, surfaces with controlled wetting for printed electronics, surfaces with antireflective, antiadhesive, antifriction properties, modifying channel geometries for micro- and nanofluidics. The applications range from fundamental research with large scale fabilities to industrial products.

Main interest: Development of novel methods for topological and chemical surface patterns, in particular using nanoimprint lithography and other molding techniques. Since many years we have contributed via development of technology, tools, and processes, i.e. the full toolbox for replication processes needed for academic research and industrial applications:

• We fabricate stamp originals via high resolution electron beam lithography, and have established methods for the generation of 3D surface topographies by greyscale electron beam lithography combined with selective thermal reflow. Our portfolio of 3D patterning capabilities has recently been enlarged by direct writing laser lithography (two-photon polymerization). We also profit from the sub-10 nm resolution demonstrated by EUV interference lithography at the Swiss Light Source (SLS).
• We fabricate stamps copies and workings stamps, e.g. transparent stamps for UV-assisted nanoimprint or hybrid molds with a functional topography. For this an Ormostamp layer is on top of a metal backbone is used for roll embossing and injection molding.
• We apply ultrathin antisticking layers on silicon and quartz molds, but also test materials with inherent antiadhesive properties. Recently we have been developing solutions for nickel stamps, too. We also develop solutions for chemical surface functionalization.
• We analyze mold filling and replication quality in 3D-nanoimprint and measure demolding forces for different thermoplastic and UV-curable materials. Recently we have developed models for "energy based" thermal reflow.
• We work on different applications in optics, bio-mimetrics and electronics. We have worked on contact-less polishing of 3D microlens surfaces by selective surface reflow, and on solutions to shrink dimensions of wires in flexible electronics by using prepatterned substrates for ink depositing.
• We establish imprint-based solutions for different applications and areas such as optics (refractive and diffractive elements, photonics, plasmonics, liquid crystals), biology (templates for cell growth, protein patterning and crystallization), micro- and nanofluidics (for analysis of transport through lipid bilayers) and surface wetting (via modification of hydrophilic and hydrophobic properties).

This toolbox for topological nanopatterning is further enlarged within the framework of the Institute of Polymer Nanotechnology INKA (a "joint venture" between PSI and the University of Applied Sciences and Arts Nordwestschweiz FHNW, headed by P. Magnus Kristiansen) and via collaborations with industry and research partners on national and international level. Within INKA we have gained experience in upscaling of molding processes from thermal imprint of nanogratings to injection molding of prepatterned polymer microcantilevers, by working with research and industrial partners, in student projects and large scale European projects. INKA-FHNW is focused on more industrial processes of polymer technology such as injection molding and roll-to-roll processes, and takes advantage of LMN's unique stamp fabrication capabilities.

• Diploma in electrical engineering, University of Karlsruhe, Germany, now Karlsruhe Institute of Technology KIT (work performed at ENSPS Strasbourg, France, now Télécom Physique Strasbourg, on computer generated holograms)
  
• PhD thesis in mechanical engineering, University of Karlsruhe, Germany (work performed at Institute of Microtechnology Mainz ICT-IMM, on micro-optics and LIGA-technology)
  
• Since 1994 as a staff researcher in the Laboratory for Micro- and Nanotechnology LMN at the Paul Scherrer Institut PSI in Villigen, Switzerland
  
• Head of the Polymer Nanotechnology Group INKA-PSI
  
• Lecturer at the University of Applied Sciences and Arts (FH) Nordwestschweiz, FHNW, Windisch, Switzerland, on “Micro- and Nanotechnology”, and in master courses and summer schools
  
• Visiting professor (2011) in the Optofluidics group in the Department of Micro- and Nanotechnology (Nanotech) at the Technical University of Denmark DTU in Kongens Lyngby, Denmark
  
• From 2019 on consultant on research integrity at the Paul Scherrer Institut
  
  

Key Papers

R. Kirchner, V. Guzenko, and H. Schift, Single-digit 6-nm multilevel patterns by electron beam grayscale lithography, Adv. Opt. Techn. (2019) 1-6.

B. Horváth, B. Křivová, and H. Schift, Nanoimprint meets microfluidics: Development of metal wires from nanoparticle ink filled capillaries, in press, accepted Manuscript, Micro and Nano Eng., 3 (2019) 22-30.

B. Horváth, B. Křivová, S. Bolat, and H. Schift, Fabrication of large area sub‐200 nm conducting electrode arrays by self‐confinement of spincoated metal nanoparticle inks, Adv. Mat. Technol. 3(4) (2019) 1800652 (11 pp).

R. Kirchner and H. Schift, Thermal reflow of polymers for innovative and smart 3D structures: A review, Mat. Sci. Semiconduct. Proc. 92 (2019) 58-72.

R. Kirchner, N. Chidambaram, and H. Schift, Benchmarking surface selective vacuum ultraviolet and thermal postprocessing of thermoplastics for ultrasmooth 3-D-printed micro-optics, Opt. Eng. 57(4), 041403 (2018) (13 pp).

V.J. Cadarso, N. Chidambaram, L. Jacot-Descombes, and H. Schift, High-aspect-ratio nanoimprint process chains,
Microsystems & Nanoengineering 3, (2017) 17017 (12 pp).

N. Chidambaram, R. Kirchner, R. Fallica, L. Yu, M. Altana, and H. Schift, Selective surface smoothening of polymer microlenses by depth confined softening, Adv. Mater. Technol., (2017) 1700018 (10 pp).

N. Chidambaram, R. Kirchner, M. Altana, and H. Schift, High fidelity 3D thermal nanoimprint with UV curable polydimethyl siloxane stamps, J. Vac. Sci. Technol. B 34, (2016) 06K401 (6 pp) – including cover page JVST B (11/2016).

V.J. Cadarso, A. Llobera, M. Puyol, and H. Schift, Integrated photonic nanofences: combining subwavelength waveguides with enhanced evanescent field for sensing applications, ACS Nano 10 (2016) 778–785.

H. Schift, NIL puts its stamp on fabrication, Feature in Physics World, Focus on: Nanotechnology, May 2015.

H. Schift, Nanoimprint lithography: 2D or not 2D? A review, Applied Physics A 121(2) 415-435 (2015).

A. Schleunitz, V.A. Guzenko, M. Messerschmidt, H. Atasoy, R. Kirchner, and H. Schift, Novel 3D micro- and nanofabrication method using thermally activated selective topography equilibration (TASTE) of polymers, Nano Convergence 1:7 (2014), Springer open access (28 February 2014).

P. Urwyler, H. Schift, J. Gobrecht, O. Häfeli, M. Altana, F. Battiston, and B. Müller, Surface patterned polymer micro-cantilever arrays for sensing, Sensors and Actuators A: Physical 172(1) (2011) 2-8.

A. Schleunitz and H. Schift, Fabrication of 3-D nanoimprint stamps with continuous reliefs using dose-modulated electron beam lithography and thermal reflow,J. Micromech. Microeng. 20 (2010) 095002.

H. Schift, Nanoimprint lithography: An old story in modern times? A review, J. Vac. Sci. Technol. B 26(2), 458-480 (2008).

H. Schift, S. Saxer, S. Park, C. Padeste, U. Pieles, and J. Gobrecht, Controlled co-evaporation of silanes for nanoimprint stamps,
Nanotechnol. 16, S171-S175 (2005).

D. Falconnet, D. Pasqui, S. Park, R. Eckert, H. Schift, J. Gobrecht, R. Barbucci, and M. Textor, A novel approach to produce protein nanopatterns by combining nanoimprint and molecular self-assembly, Nanolett. 4 (10), 1909-1914 (2004).

H. Schift, L.J. Heyderman, M. Auf der Maur, and J. Gobrecht, Pattern formation in hot embossing of thin polymer films,
Nanotechnol. 12, 173-177 (2001).

L.J. Heyderman, H. Schift, C. David, J. Gobrecht, and T. Schweizer, Flow behaviour of thin polymer films used for hot embossing lithography, Microelectron. Eng. 54, 229-245 (2000).

R.W. Jaszewski, H. Schift, B. Schnyder, A. Schneuwly, and P. Gröning, The deposition on anti-adhesive ultra-thin teflon-like films and their interaction with polymers during hot embossing, Appl. Surf. Sci. 143, 301-308 (1999).

Books and Book Chapters

H. Schift and A. Kristensen, Nanoimprint lithography - patterning resists using molding. Chapter (Part A/9) in Handbook of Nanotechnology, Vol. ed. B. Bhushan, third edition, 2010, Springer Verlag Berlin Heidelberg, Germany. ISBN: 978-3-642-02524-2, XLVIII, with DVD, 271-312 (2010). Fourth edition (2017), revised and updated.

P. Urwyler and H. Schift, Nanostructured polymers for medical applications, Chapter in Nanoscience and Nanotechnology for Human Health, Eds. B. Müller and M. Van de Voorde, First Edition, Wiley-VCH Verlag GmbH & Co. KGaA, ISBN: 978-3-527-33860-3, 293-314 (2017).

S. Park and H. Schift, Nanoimprinting technology for biological applications, Chapter in BioMEMS and biomedical nanotechnology, ed. M. Ferrari, Vol-4 ”Biomolecular Sensing, Processing and Analysis”, Vol. eds. R. Bashir, S. Wereley, Springer Verlag, Berlin, Germany. ISBN: 978-0-387-25561-3, 95-117 (2007).

H. Schift, Roll embossing and roller imprint, Chapter (5) in “Science and new technology in nanoimprint”. Volume editor Y. Hirai. Frontier Publishing Co., Ltd., Japan, ISBN4-902410-09-5, English 74-89, Japanese translation (extract) 90-93 (2006).

H. Schift and L.J. Heyderman, Nanorheology - squeezed flow in hot embossing of thin films, Chapter (4) in Alternative lithography – unleashing the potential of nanotechnology. Vol. ed. C. Sotomayor Torres, book series on Nanostructure Science and Technology in Kluwer Academic/Plenum Publishers, ed. D.J. Lockwood. ISBN 0-306-47858-7, 46-76 (2003).

FREE Download NaPa Library of Processes, FIRST EDITION - NaPa LoP with results of the NaPa-Project (nanopatterning and applications) (2008). Editor H. Schift, published by the NaPa-consortium represented by J. Ahopelto, printed by microresist technology, ISBN 978-3-00-024396-7, SECOND EDITION - NaPANIL LoP, with results of the NaPANIL-project (nanopatterning, production and applications based on nanoimprint lithography) (2012), THIRD EDITION - NaPANIL LoP, revised and updated (2014).
 

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