Photolithographic Patterning of Bi-Helical Tracks onto Conical Substrates

Purvis, Alan; McWilliam, Richard; Johnson, Simon; Seed, N.; Williams, Gavin; Maiden, Andrew; Ivey, Peter

Abstract

We demonstrate the direct photolithographic patterning of a grossly non-planar substrate by creating 62 micron helical tracks on a 22 mm high cone. The projection of focused light on to the three dimensional surface is achieved using a computer generated hologram (CGH) suitably illuminated so as to create the required pattern on the photoresist coated surface. The approach adopted forms the basis of a novel method for the patterning of non-planar structures. We address the key challenges encountered for the implementation of holographic photolithography in three dimensions, including mask design and manufacture, exposure compensation, mask alignment and chemical processing. Control of line width and resolution over the non-planar surface is critical. We describe the methods adopted and critically assess the structures created by this process. The bi-helical cone is representative of a broadband, high frequency coil like structure, known in wireless communications as a log-periodic antenna.

Citation

Purvis, A., McWilliam, R., Johnson, S., Seed, N., Williams, G., Maiden, A., & Ivey, P. (2007). Photolithographic Patterning of Bi-Helical Tracks onto Conical Substrates. Journal of Micro/Nanopatterning, Materials, and Metrology, 6(4), https://doi.org/10.1117/1.2824377

• Journal Article Type: Article
• Online Publication Date: Dec 1, 2007
• Publication Date: Dec 1, 2007
• Deposit Date: Oct 10, 2008
• Publicly Available Date: Oct 8, 2009
• Journal: Journal of Micro/Nanolithography, MEMS, and MOEMS
• Print ISSN: 1932-5150
• Electronic ISSN: 1932-5134
• Publisher: Society of Photo-optical Instrumentation Engineers
• Peer Reviewed: Peer Reviewed
• Volume: 6
• Issue: 4
• DOI: https://doi.org/10.1117/1.2824377
• Keywords: Holography, Lithography, Log-periodic antennas.
• Public URL: https://durham-repository.worktribe.com/output/1560715
• Publisher URL: http://spie.org/x865.xml