Photolithography Services

Platypus Technologies offers services in photolithography for fabrication of patterned surfaces. Applications include fabrication of chemical sensors, biosensors, electrodes, and optical devices.

Photolithography is a process that uses ultraviolet (UV) light to pattern a light-sensitive coating (known as photoresist) deposited on a substrate.  A mask is placed atop the photoresist to block UV light from illuminating certain areas, so that only unmasked regions are exposed to light.  The geometric pattern in the photoresist is revealed by removing the unprocessed areas using an appropriate organic or aqueous solvent.  Platypus Technologies stocks both negative and positive photoresists for diverse applications.

The photoresist pattern is transferred to a thin metal film or dielectric film via two different techniques: metal lift-off or wet etching.

Metal Lift-Off:  Metal lift-off is a process where a substrate (glass, silicon, ceramic, etc) is first coated with a patterned photoresist film, similar to a stencil. Next, a metal or dielectric film is deposited onto the photoresist-coated substrate.  The metal or dielectric film binds to the substrate only at the areas unprotected by the photoresist film.  The areas of the substrate protected by the photoresist do not bind to the deposited metal or dielectric film. Finally, the photoresist is dissolved in a solvent bath to reveal the patterned metal or dielectric film bound to the substrate.

Wet Etching:  For wet etching, the photoresist is deposited and patterned atop the metal or dielectric film.  Areas of the metal that are not protected by the photoresist are removed by carefully selected liquid chemicals.  The photoresist is removed by a solvent, or via O2 plasma, to reveal the pattern of the metal film.

Available surface pre- and post-treatment preparation methods include O2 plasma or deposition of silanes (e.g. HMDS, fluorinated silanes), and protective coatings.

Photolithography services at Platypus Technologies are carried in a dedicated cleanroom facility (class 1000) equipped with environmental controls, ensuring high quality parts for our customers.

Applications include patterned wafers for microfluidics, inter-digitated electrodes, electrochemical sensors, beam-splitting optical plates, pixel arrays, indium tin oxide (ITO) electrodes, flexible electrodes, and more.


  • 365-nm highly collimated UV exposure system
  • Photoresist types: positive, lift-off.
  • Substrates: glass, silicon, metals, ceramics, polyimide.
  • Minimum feature resolution: 5-µm
  • Circular substrates up to 6”-dia
  • Square substrates up to 4”x4”

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