Shadow mask process

- deposition methods : evaporation, sputtering...

  Due to mean free path, shadow effect will be a problem when evaporation is
used.
  Some technic like substrate lotation and use of thin mask is helpful to avoid
shadow effect.

  Doing sputtering, you must adhere the mask to substrate closely not to
penetrate the atoms penetrate under the mask.

- mask material : metal(by electroforming, etching or laser machining) or glass
  finest mask is acquired by electroforming.
 glass mask has thermal stability and optical  transparency.(>30um,
thickness(50-500um))