Removing uncured emulsion from stencils during photomask production

摘要

Uncured emulsion is effectively washed from a stencil in the production of photomasks by mounting a drum rotatable about a horizontal axis within a portable cabinet. The drum is driven by a small (e.g. variable speed 1/16 HP) electric motor and spins at about 50-100 rpm. Water is sprayed onto the stencil mounted on the drum at about 80 psi by 4-10 V-jet nozzles. Liquid running off the stencil is collected by a catch basin mounted just below the drum, and passes through a drain pipe with strainer into a heat insulated holding tank with an electric resistance heating element, and is recirculated from the tank to the spray nozzles-by a high pressure pump. The pump and motor are controlled by a timer, and after completion of the washing cycle the stencil is removed from the cabinet.