Top-down

Manufacturing - Top-down - About the sector text

Top-down processes include lithography, printing, etching and ball-milling.

  • Nanoimprint lithography is used to create nanoscale features by printing onto a surface. There are several methods including
    • Thermoplastic nanoimprint lithography (T-NIL) in which a layer of thermoplastic polymer is put onto a surface, pressed onto a mould, heated and then cooled leaving a pattern on the polymer.
    • Photo nanoimprint lithography (P-NIL) in which a liquid which it light-curable is applied to a surface, pressed onto a transparent mould and light is used to cure the material which retains the imprint of the mould.
  • Dip-pen lithography uses an atomic force microscope (AFM) as a mechano–electrochemical pen to “write” with atoms on a surface.
  • In nanocontact printing, a pattern is stamped onto a material. The stamps are prepared using lithography and a thin layer of material is used to coat them. The stamp is pressed onto the material, leaving a thin layer behind (some curing process may be required).
  • Reactive ion etching uses a chemically-active plasma to remove (etch) layers of material selectively from a substrate.
  • Ball milling uses balls in a mill to progressively break down a powder into finer and finer particles. It is a rather crude technique and is often used to prepare material to enter into a second production process.