SOURCE: Alan Bleier
ADDED: 10/27/15
Expose patterns in Dow-Corning XR-1541 (Hydrogen silsesquioxane or HSQ) on the JEOL JBX 9500 FSZ electron beam lithography system at 100 kV. Features less than 10 nm in size can be produced.

 

Apply Proximity correction and biasing to pattern data using TRACER and BEAMER by GenISys GmbH

  • Generate the point spread function for proximity correction by Monte Carlo simulation with GeniSys TRACER for a 20 nm film of HSQ on silicon or other substrate.
  • In BEAMER, perform biasing by subtracting 1 nm from the edges of all shapes in the pattern with the BIAS module.
  • In the proximity correction module, include a short range correction and allow as many as 256 different relative doses to be assigned to the pattern shapes. Some small features may receive double the base dose or more.
  • In the Export module, use shot pitch fracturing to fracture the pattern for e beam shots spaced by 1 nm with shot pitch set to 1 (but on the JEOL use shot pitch 2 because minimum shot spacing is actually 0.5 nm).

Job File Editing

  • Use beam current of 0.5 nA
  • For a dose test on a silicon substrate, use six base doses from 8000 uC/cm2 to 9500 uC/cm2, with 3.5% increases from one dose to the next

Substrate Preparation

  • Dilute 6% solids HSQ resist in a 1:5 ratio with MIBK in a graduated cylinder
  • Clean substrate on spinner with acetone and isopropanol
  • Spin at 2000 rpm for 60 s
  • Bake for 2 minutes at 170° C
  • Thickness can be measured with the Woollam Spectroscopic Ellipsometer using a Cauchy model, fitting thickness, A, B, and C.
  • Apply Espacer HX02 conducting polymer by spinning at 5000 rpm for 60 s. No baking is required after application of Espacer.

After exposure

  • Rinse off Espacer with deionized water for 1 min
  • Develop for 4 min in “salty developer” [1]
  • Rinse for 1 min in DI water and 1 min in isopropanol
  • Repeat the two rinse steps to more completely remove residue and debris
  • Dry with nitrogen

[1] J. K. W. Yang and K. K. Berggren, “Using high-contrast salty development of hydrogen silsesquioxane for sub-10-nm half-pitch lithography,” Journal of Vacuum Science and Technology B: Microelectronics and Nanometer Structures, vol. 25, no. 6, pp. 2025 – 2029, 2007.


DISCLAIMER

All recipes are meant as a starting point for your process and have been obtained under very specific control conditions. You will likely require some iteration of characterization runs in which you tweak the process time or process parameters. If you are not achieving the expected results, CNF staff can help you. Please seek the tool owner's advice. You should expect some process refinement when you are establishing a new process or have not run a process step for some time – this is normal.

Remember that you maintain responsibility for your use of all CNF tools, and should be careful not to damage the equipment when running special recipes. Contact the tool manager before attempting any unusual processing.

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