Microelectronics Process Screens
Printing screens are made from an interwoven mesh of nylon or stainless-steel, whjch is coated with a light-sensitive emulsion. A photopositive of a print layer which has been generated from the CAD drawing file is placed onto the screen and then exposed to UV light. The emulsion which is exposed to the light turns hard whereas the emulsion under the photopositive remains soft and is washed out to leave a print pattern on the screen.
Very fine lines can be achieved by the use of metal film stensils.