Tailored molecular glass resists for Scanning Probe Lithography Christian Neuber *a , Hans-Werner Schmidt a , Peter Strohriegl a , Andreas Ringk a , Tristan Kolb a , Andreas Schedl a , Vincent Fokkema b , Marijn G.A. van Veghel b , Mike Cooke c , Colin Rawlings d , Urs Dürig d , Armin Knoll d , Jean- François de Marneffe e , Ziad el Otell e , Marcus Kaestner f , Yana Krivoshapkina f , Matthias Budden f , Ivo W. Rangelow f a University of Bayreuth, Bayreuth, 95440, Germany; b VSL Dutch Metrology Institute, 2629 JA Delft, Netherlands; c Oxford Instruments Nanotechnology Tools Limited, Oxford, 1581072, England; d IBM Research, Zuerich, 8803 Rueschlikon, Switzerland; e IMEC, B-3001 Leuven, Belgium; f Ilmenau University of Technology, 98693 Ilmenau, Germany ABSTRACT In the presented work solvent-free film preparation from tailored molecular glass resists, their thermal analysis, the characterization of etch resistance for plasma etching transfer processes, and the evaluation of the patterning performance using scanning probe lithography (SPL) tools, in particular electric field and thermal based SPL, are demonstrated. Therefore a series of fully aromatic spiro-based and tris-substituted twisted resist materials were systematically investigated. The materials feature very high glass transition temperatures of up to 173 °C, which allows solvent-free thin film preparation by physical vapor deposition (PVD) due to their high thermal stability. The PVD prepared films offer distinct advantages compared to spin coated films such as no pinholes, defects, or residual solvent domains, which can locally affect the film properties. In addition, PVD prepared films do not need a post apply bake (PAB) and can be precisely prepared in the nanometer range layer thickness. An observed sufficient plasma etching resistance is promising for an efficient pattern transfer even by utilizing only 10 nm thin resist films. Their lithographic resolution potential is demonstrated by a positive and a negative tone patterning using electric field, current controlled scanning probe lithography (EF-CC-SPL) at the Technical University of Ilmenau or thermal scanning probe lithography (tSPL) investigations at the IBM Research - Zurich. High resolution tSPL prepared patterns of 11 nm half pitch and at 4 nm patterning depth are demonstrated. Keywords: nanomanufacturing, molecular glass resist, scanning probe lithography, physical vapor deposition, plasma etching 1. INTRODUCTION A molecular glass is a super-cooled, highly viscous liquid or solid material, which shows a stable or metastable amorphous state. The amorphous state results in advantageous properties like good transparency, easy processability, high homogeneity and isotropic properties. 1 In comparison to high molecular weight polymers, the molecular glass materials feature a well-defined molecular structure and typically a small molecular size. Consequently, they do not undergo chain entanglement and show high vapor pressure and low viscosities above their glass transition temperatures. In summary, these materials are ideal candidates for future nanolithography as the patterning resolution can theoretically reach the building block size, which means for molecular glasses the size of a small molecule. 2 The first utilization of molecular glasses in lithography was introduced by Shirota and coworkers. In this early work from 1996 they investigated a non-chemically amplified resist based on branched phenylbenzene and triphenyleneamine structures for electron beam lithography to realize successfully 70 nm features. 3 An overview of molecular glass resists has been recently published. 4,5 Here, the overall potential of this resist class is highlighted, but further research is required to overcome the performance of highly optimized polymeric resists in future. In addition, molecular glass resists tailored with respect to a high thermal stability are applicable to the film preparation by PVD. 6,7 The alternative solvent-free thin * christian.neuber@uni-bayreuth.de; phone: +49921 55 3290; fax: +49921 55 3246; http://www.chemie.uni-bayreuth.de/mci Advances in Patterning Materials and Processes XXXII, edited by Thomas I. Wallow, Christoph K. Holhle, Proc. of SPIE Vol. 9425, 94250E · © 2015 SPIE CCC code: 0277-786X/15/$18 · doi: 10.1117/12.2085734 Proc. of SPIE Vol. 9425 94250E-1 Downloaded From: http://proceedings.spiedigitallibrary.org/ on 03/30/2015 Terms of Use: http://spiedl.org/terms