Light is used to form an image on the coated surface, using a photographic negative
The exposed image is developed using a solvent
Some of the photoresist remains to protect the surface
The photoresist pattern is a precise copy of the image on the negative
The rest of the surface is uncoated and subject of further treatment
The photoresist image is also called a mask
Photoresists are capable of producing patterns of extremely fine detail and have important commercial applications:
Photolithography and printing
Decorative arts including glass
Computer chips and circuit boards
Nanotechnology
Electroforming of intricate metal objects
The selected example illustrates the process of electroforming metal patterns using a photoresist mask.
Materials
Small sheet of polished stainless steel, 1”x2”
Photoresist stencil on a thin plastic sheet
Electroplating bath containing a solution of copper sulfate
Copper wire as cathode (positive electrode)
Procedure
An office copier or a laser printer is used to copy a pattern on a special (blue) paper. The pattern can be transferred to a sheet of stainless steel using a hot iron to obtain a thin layer of photoresist. The metal sample is then placed in an electrochemical bath and is electroplated with a film of copper metal.
Because the transfer pattern acts as a mask, metal is only deposited in the uncovered regions. When the metal deposited has reached a sufficient thickness, it can be lifted from the surface using a razor blade (Figure 1). The result is a metal object with delicate details that duplicate the pattern of the original drawing (Figure 2).
An office copier or a laser printer is used to copy a pattern on a special (blue) paper. The pattern can be transferred to a sheet of stainless steel using a hot iron to obtain a thin layer of photoresist. The metal sample is then placed in an electrochemical bath and is electroplated with a film of copper metal. 