Closed-loop high-speed 3D thermal probe nanolithography

A. W. Knoll; M. Zientek; L. L. Cheong; C. Rawlings; P. Paul; F. Holzner; J. L. Hedrick; D. J. Coady; R. Allen; U. Dürig

doi:10.1117/12.2046201

28 March 2014 Closed-loop high-speed 3D thermal probe nanolithography

A. W. Knoll, M. Zientek, L. L. Cheong, C. Rawlings, P. Paul, F. Holzner, J. L. Hedrick, D. J. Coady, R. Allen, U. Dürig

Proceedings Volume 9049, Alternative Lithographic Technologies VI; 90490B (2014) https://doi.org/10.1117/12.2046201
Event: SPIE Advanced Lithography, 2014, San Jose, California, United States

Abstract

Thermal Scanning Probe Lithography (tSPL) is an AFM based patterning technique, which uses heated tips to locally evaporate organic resists such as molecular glasses [1] or thermally sensitive polymers.[2][3] Organic resists offer the versatility of the lithography process known from the CMOS environment and simultaneously ensure a highly stable and low wear tip-sample contact due to the soft nature of the resists. Patterning quality is excellent up to a resolution of sub 15 nm,[1] at linear speeds of up to 20 mm/s and pixel rates of up to 500 kHz.[4] The patterning depth is proportional to the applied force which allows for the creation of 3-D profiles in a single patterning run.[2] In addition, non-destructive imaging can be done at pixel rates of more than 500 kHz.[4] If the thermal stimulus for writing the pattern is switched off the same tip can be used to record the written topography with Angstrom depth resolution. We utilize this unique feature of SPL to implement an efficient control system for reliable patterning at high speed and high resolution. We combine the writing and imaging process in a single raster scan of the surface. In this closed loop lithography (CLL) approach, we use the acquired data to optimize the writing parameters on the fly. Excellent control is in particular important for an accurate reproduction of complex 3D patterns. These novel patterning capabilities are equally important for a high quality transfer of two-dimensional patterns into the underlying substrate. We utilize an only 3-4 nm thick SiOx hardmask to amplify the 8±0.5 nm deep patterns created by tSPL into a 50 nm thick transfer polymer. The structures in the transfer polymer can be used to create metallic lines by a lift-off process or to further process the pattern into the substrate. Here we demonstrate the fabrication of 27 nm wide lines and trenches 60 nm deep into the Silicon substrate.[5] In addition, the combined read and write approach ensures that the lateral offset between read and write field is minimized. Thus we achieve high precision in marker-less stitching of patterning fields. A 2D cross-correlation technique is used to determine the offset of a neighboring patterning field relative to a previously written field with an accuracy of about 1 nm. We demonstrate stitching of 1 μm2 fields with ~5 nm accuracy and stitching of larger 10x10 μm2 fields with 10 nm accuracy.[6]

Citation Download Citation

A. W. Knoll, M. Zientek, L. L. Cheong, C. Rawlings, P. Paul, F. Holzner, J. L. Hedrick, D. J. Coady, R. Allen, and U. Dürig "Closed-loop high-speed 3D thermal probe nanolithography", Proc. SPIE 9049, Alternative Lithographic Technologies VI, 90490B (28 March 2014); https://doi.org/10.1117/12.2046201

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available