{"id":2838,"date":"2011-06-23T18:41:27","date_gmt":"2011-06-23T18:41:27","guid":{"rendered":"https:\/\/mtlsites.mit.edu\/annual_reports\/2011\/?p=2838"},"modified":"2011-07-19T15:31:05","modified_gmt":"2011-07-19T15:31:05","slug":"scanning-neon-and-helium-ion-beam-lithography","status":"publish","type":"post","link":"https:\/\/mtlsites.mit.edu\/annual_reports\/2011\/scanning-neon-and-helium-ion-beam-lithography\/","title":{"rendered":"Scanning-neon and Helium-ion-beam Lithography"},"content":{"rendered":"<div class=\"pf-content\"><p>A commercially-available scanning-helium-ion microscope of high source brightness<sup> [<a href=\"#footnote_0_2838\" id=\"identifier_0_2838\" class=\"footnote-link footnote-identifier-link\" title=\"B. W. Ward, J. A. Notte, and N. P. Economou, &ldquo;Helium ion microscope: a new tool for nanoscale microscopy and metrology,&rdquo; J. Vac. Sci. and Technol. B, vol. 24, pp. 2871-2874, 2006.\">1<\/a>] <\/sup> has been modified for operation with neon gas. This neon system had been evaluated for nano-machining<sup> [<a href=\"#footnote_1_2838\" id=\"identifier_1_2838\" class=\"footnote-link footnote-identifier-link\" title=\"S. Tan, R. Livengood, D. Shima, J. Notte, and S. McVey, &ldquo;Gas field ion source and liquid metal ion source charged particle material interaction study for semiconductor nanomachining applications,&rdquo; J. Vac. Sci. and Technol. B, vol. 28, pp. C6F15-C6F21, 2010.\">2<\/a>] <\/sup>, but not for resist-based lithography, as has been done with helium systems<sup> [<a href=\"#footnote_2_2838\" id=\"identifier_2_2838\" class=\"footnote-link footnote-identifier-link\" title=\"D. Winston, B. M. Cord, B. Ming, D. C. Bell, W. F. DiNatale, L. A. Stern, A. E. Vladar, M. T. Postek, M. K. Mondol, J. K. W. Yang, and K. K. Berggren, &ldquo;Scanning-helium-ion-beam lithography with hydrogen silsesquioxane resist,&rdquo; J. Vac. Sci. Technol. B, vol. 27, pp. 2702-2706, 2009.\">3<\/a>] <\/sup><sup> [<a href=\"#footnote_3_2838\" id=\"identifier_3_2838\" class=\"footnote-link footnote-identifier-link\" title=\"V. Sidorkin, E. van Veldhoven, E. van der Drift, P. Alkemade, H. Salemink, and D. Maas, &ldquo;Sub-10-nm nanolithography with a scanning helium beam,&rdquo; J. Vac. Sci. Technol. B, vol. 27, pp. L18-L20, 2009.\">4<\/a>] <\/sup>. The neon system may enable a lithography process with higher resolution than any scanning-particle system to date. This possibility is due to the combination of the high-brightness source and the expected reduction of secondary-electron (SE) range relative to electrons or helium ions. In addition, the expected increase in SE yield relative to electrons or helium ions may lead to a lithography process with high sensitivity. This high sensitivity could allow critical doses below substrate-damage thresholds. Figure 1 presents preliminary data on the point-spread function (PSF) of neon compared to helium.<\/p>\n<p>The Stopping and Range of Ions in Matter (SRIM) is a popular, industry-standard tool for simulating the trajectories of incident ions in a target sample. However, SRIM does not simulate the trajectories of secondary electrons (SEs) produced by ion-sample interactions. SEs are responsible for exposure of resist and thus figure prominently in modeling of electron-beam lithography and proton-beam lithography. We developed a hybrid approach to modeling helium-ion lithography that combines the power and ease-of-use of SRIM with the results of recent work simulating SE yield in helium-ion microscopy<sup> [<a href=\"#footnote_4_2838\" id=\"identifier_4_2838\" class=\"footnote-link footnote-identifier-link\" title=\"D. Winston, J. Ferrera, L. Battistella, A. E. Vladar, and K. K. Berggren, &ldquo;Modeling the point-spread function in helium-ion lithography,&rdquo; submitted for publication.\">5<\/a>] <\/sup>. This approach traces along SRIM-produced helium-ion trajectories, generating and simulating trajectories for these SEs using a Monte Carlo method. Figure\u00a02 illustrates the utility of our software, which can also simulate electron beams.<\/p>\n\n\t\t<style type=\"text\/css\">\n\t\t\t#gallery-1 {\n\t\t\t\tmargin: auto;\n\t\t\t}\n\t\t\t#gallery-1 .gallery-item {\n\t\t\t\tfloat: left;\n\t\t\t\tmargin-top: 10px;\n\t\t\t\ttext-align: center;\n\t\t\t\twidth: 50%;\n\t\t\t}\n\t\t\t#gallery-1 img {\n\t\t\t\tborder: 2px solid #cfcfcf;\n\t\t\t}\n\t\t\t#gallery-1 .gallery-caption {\n\t\t\t\tmargin-left: 0;\n\t\t\t}\n\t\t\t\/* see gallery_shortcode() in wp-includes\/media.php *\/\n\t\t<\/style>\n\t\t<div id='gallery-1' class='gallery galleryid-2838 gallery-columns-2 gallery-size-medium'><dl class='gallery-item'>\n\t\t\t<dt class='gallery-icon landscape'>\n\t\t\t\t<a href='https:\/\/mtlsites.mit.edu\/annual_reports\/2011\/wp-content\/blogs.dir\/10\/files\/2011\/06\/winston_scanningneon_01.png' rel=\"lightbox[2838]\"><img width=\"300\" height=\"204\" src=\"https:\/\/mtlsites.mit.edu\/annual_reports\/2011\/wp-content\/blogs.dir\/10\/files\/2011\/06\/winston_scanningneon_01-300x204.png\" class=\"attachment-medium size-medium\" alt=\"Figure 1\" loading=\"lazy\" aria-describedby=\"gallery-1-2839\" srcset=\"https:\/\/mtlsites.mit.edu\/annual_reports\/2011\/wp-content\/blogs.dir\/10\/files\/2011\/06\/winston_scanningneon_01-300x204.png 300w, https:\/\/mtlsites.mit.edu\/annual_reports\/2011\/wp-content\/blogs.dir\/10\/files\/2011\/06\/winston_scanningneon_01.png 734w\" sizes=\"(max-width: 300px) 100vw, 300px\" \/><\/a>\n\t\t\t<\/dt>\n\t\t\t\t<dd class='wp-caption-text gallery-caption' id='gallery-1-2839'>\n\t\t\t\tFigure 1: Comparison of inverse dose versus measured feature half-width, which is the radial distance to the threshold for exposure, for 20 keV Ne+ and 30 keV He+, in thin (< 20 nm) HSQ on Si. We see from this plot that the neon beam is somewhat broader and also requires lower doses to achieve exposure.\n\t\t\t\t<\/dd><\/dl><dl class='gallery-item'>\n\t\t\t<dt class='gallery-icon landscape'>\n\t\t\t\t<a href='https:\/\/mtlsites.mit.edu\/annual_reports\/2011\/wp-content\/blogs.dir\/10\/files\/2011\/06\/winston_scanningneon_02-e1308854381948.png' rel=\"lightbox[2838]\"><img width=\"300\" height=\"263\" src=\"https:\/\/mtlsites.mit.edu\/annual_reports\/2011\/wp-content\/blogs.dir\/10\/files\/2011\/06\/winston_scanningneon_02-300x263.png\" class=\"attachment-medium size-medium\" alt=\"Figure 2\" loading=\"lazy\" aria-describedby=\"gallery-1-2840\" srcset=\"https:\/\/mtlsites.mit.edu\/annual_reports\/2011\/wp-content\/blogs.dir\/10\/files\/2011\/06\/winston_scanningneon_02-300x263.png 300w, https:\/\/mtlsites.mit.edu\/annual_reports\/2011\/wp-content\/blogs.dir\/10\/files\/2011\/06\/winston_scanningneon_02-1024x900.png 1024w, https:\/\/mtlsites.mit.edu\/annual_reports\/2011\/wp-content\/blogs.dir\/10\/files\/2011\/06\/winston_scanningneon_02-e1308854381948.png 800w\" sizes=\"(max-width: 300px) 100vw, 300px\" \/><\/a>\n\t\t\t<\/dt>\n\t\t\t\t<dd class='wp-caption-text gallery-caption' id='gallery-1-2840'>\n\t\t\t\tFigure 2: (a) Projection plot of trajectories for incident particles and their SEs, for helium-ion and electron beams, in 12-nm-thick HSQ on Si. To reduce calculation time and to focus attention on the short-range effects on feature size such as forward scattering and SE range, the Si layer is a 36-nm-thick membrane rather than a bulk substrate.  The image is cropped at the base of the resist layer for clarity. (b) Simulated PSFs in 12-nm-thick HSQ on bulk Si for each of the four beams in (a): 30 keV He+ (diamonds), 30 keV e- (triangles), 10 keV e- (squares), and 5 keV e- (x\u2019s).\n\t\t\t\t<\/dd><\/dl><br style=\"clear: both\" \/>\n\t\t<\/div>\n\n<\/div><ol class=\"footnotes\"><li id=\"footnote_0_2838\" class=\"footnote\">B. W. Ward, J. A. Notte, and N. P. Economou, &#8220;Helium ion microscope: a new tool for nanoscale microscopy and metrology,&#8221; <em>J. Vac. Sci. and Technol. B, <\/em>vol. 24, pp. 2871-2874, 2006. [<a href=\"#identifier_0_2838\" class=\"footnote-link footnote-back-link\">&#8617;<\/a>]<\/li><li id=\"footnote_1_2838\" class=\"footnote\">S. Tan, R. Livengood, D. Shima, J. Notte, and S. McVey, &#8220;Gas field ion source and liquid metal ion source charged particle material interaction study for semiconductor nanomachining applications,&#8221; <em>J. Vac. Sci. and Technol. B, <\/em>vol. 28, pp. C6F15-C6F21, 2010. [<a href=\"#identifier_1_2838\" class=\"footnote-link footnote-back-link\">&#8617;<\/a>]<\/li><li id=\"footnote_2_2838\" class=\"footnote\">D. Winston, B. M. Cord, B. Ming, D. C. Bell, W. F. DiNatale, L. A. Stern, A. E. Vladar, M. T. Postek, M. K. Mondol, J. K. W. Yang, and K. K. Berggren, &#8220;Scanning-helium-ion-beam lithography with hydrogen silsesquioxane resist,&#8221; <em>J. Vac. Sci. Technol. B, <\/em>vol. 27, pp. 2702-2706, 2009. [<a href=\"#identifier_2_2838\" class=\"footnote-link footnote-back-link\">&#8617;<\/a>]<\/li><li id=\"footnote_3_2838\" class=\"footnote\">V. Sidorkin, E. van Veldhoven, E. van der Drift, P. Alkemade, H. Salemink, and D. Maas, &#8220;Sub-10-nm nanolithography with a scanning helium beam,&#8221; <em>J. Vac. Sci. Technol. B, <\/em>vol. 27, pp. L18-L20, 2009. [<a href=\"#identifier_3_2838\" class=\"footnote-link footnote-back-link\">&#8617;<\/a>]<\/li><li id=\"footnote_4_2838\" class=\"footnote\">D. Winston, J. Ferrera, L. Battistella, A. E. Vladar, and K. K. Berggren, &#8220;Modeling the point-spread function in helium-ion lithography,&#8221; submitted for publication. [<a href=\"#identifier_4_2838\" class=\"footnote-link footnote-back-link\">&#8617;<\/a>]<\/li><\/ol>","protected":false},"excerpt":{"rendered":"<p>A commercially-available scanning-helium-ion microscope of high source brightness [1] has been modified for operation with neon gas. This neon system&#8230;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":[],"categories":[5528,6083],"tags":[4201,41,6114],"_links":{"self":[{"href":"https:\/\/mtlsites.mit.edu\/annual_reports\/2011\/wp-json\/wp\/v2\/posts\/2838"}],"collection":[{"href":"https:\/\/mtlsites.mit.edu\/annual_reports\/2011\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/mtlsites.mit.edu\/annual_reports\/2011\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/mtlsites.mit.edu\/annual_reports\/2011\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/mtlsites.mit.edu\/annual_reports\/2011\/wp-json\/wp\/v2\/comments?post=2838"}],"version-history":[{"count":3,"href":"https:\/\/mtlsites.mit.edu\/annual_reports\/2011\/wp-json\/wp\/v2\/posts\/2838\/revisions"}],"predecessor-version":[{"id":4006,"href":"https:\/\/mtlsites.mit.edu\/annual_reports\/2011\/wp-json\/wp\/v2\/posts\/2838\/revisions\/4006"}],"wp:attachment":[{"href":"https:\/\/mtlsites.mit.edu\/annual_reports\/2011\/wp-json\/wp\/v2\/media?parent=2838"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/mtlsites.mit.edu\/annual_reports\/2011\/wp-json\/wp\/v2\/categories?post=2838"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/mtlsites.mit.edu\/annual_reports\/2011\/wp-json\/wp\/v2\/tags?post=2838"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}