Magnetolithography
Magnetolithography (ML) is a photoresist-less and photomaskless lithography method for patterning wafer surfaces. ML based on applying a magnetic field on the substrate using paramagnetic metal masks named "magnetic mask" placed on either topside or backside of the wafer.[1][2] Magnetic masks are analogous to a photomask in photolithography, in that they define the spatial distribution and shape of the applied magnetic field.[2] The fabrication of the magnetic masks involves the use of conventional photolithography and photoresist however.[2] The second component of the process is ferromagnetic nanoparticles (analogous to the photoresist in photolithography, e.g. cobalt nanoparticles) that are assembled over the substrate according to the field induced by the mask which blocks its areas from reach of etchants or depositing materials (e.g. dopants or metallic layers).[1][2]
ML can be used for applying either a positive or negative approach. In the positive approach, the magnetic nanoparticles react chemically or interact via chemical recognition with the substrate. Hence, the magnetic nanoparticles are immobilized at selected locations, where the mask induces a magnetic field, resulting in a patterned substrate. In the negative approach, the magnetic nanoparticles are inert to the substrate. Hence, once they pattern the substrate, they block their binding site on the substrate from reacting with another reacting agent. After the adsorption of the reacting agent, the nanoparticles are removed, resulting in a negatively patterned substrate.
ML is also a backside lithography, which has the advantage of ease in producing multilayer with high accuracy of alignment and with the same efficiency for all layers.
References
[edit]- ^ a b "Magnetolithography: From the Bottom-Up Route to High Throughput". Advances in Imaging and Electron Physics. 164: 1–27. 2010-01-01. doi:10.1016/B978-0-12-381312-1.00001-8. ISSN 1076-5670.
- ^ a b c d edited by Peter W. Hawkes (2010). Advances in imaging and electron physics. Volume 164. Amsterdam: Academic Press. ISBN 978-0-12-381313-8. OCLC 704352532.
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- Bardea, Amos; Burshtein, Noa; Rudich, Yinon; Salame, Tomer; Ziv, Carmit; Yarden, Oded; Naaman, Ron (2011-12-15). "Sensitive Detection and Identification of DNA and RNA Using a Patterned Capillary Tube". Analytical Chemistry. 83 (24). American Chemical Society (ACS): 9418–9423. doi:10.1021/ac202480w. ISSN 0003-2700. PMID 22039991.
- Bardea, Amos; Naaman, Ron (2010). "Magnetolithography". Advances in Imaging and Electron Physics. Vol. 164. Elsevier. pp. 1–27. doi:10.1016/b978-0-12-381312-1.00001-8. ISBN 978-0-12-381312-1. ISSN 1076-5670.
- Kumar, Tatikonda Anand; Bardea, Amos; Shai, Yechiel; Yoffe, Alexander; Naaman, Ron (2010-06-09). "Patterning Gradient Properties from Sub-Micrometers to Millimeters by Magnetolithography". Nano Letters. 10 (6). American Chemical Society (ACS): 2262–2267. Bibcode:2010NanoL..10.2262K. doi:10.1021/nl1013635. ISSN 1530-6984. PMID 20491500.
- Bardea, Amos; Baram, Aviad; Tatikonda, Anand Kumar; Naaman, Ron (2009-12-30). "Magnetolithographic Patterning of Inner Walls of a Tube: A New Dimension in Microfluidics and Sequential Microreactors". Journal of the American Chemical Society. 131 (51). American Chemical Society (ACS): 18260–18262. doi:10.1021/ja908675c. ISSN 0002-7863. PMID 19961172.
- Bardea, Amos; Naaman, Ron (2009-05-19). "Submicrometer Chemical Patterning with High Throughput Using Magnetolithography". Langmuir. 25 (10). American Chemical Society (ACS): 5451–5454. doi:10.1021/la900601w. ISSN 0743-7463. PMID 19382781.
- Bardea, Amos; Naaman, Ron (2009-02-06). "Magnetolithography: From Bottom-Up Route to High Throughput". Small. 5 (3). Wiley: 316–319. doi:10.1002/smll.200801058. ISSN 1613-6810. PMID 19123174.
