A filter is used in a target material supply apparatus and includes a sheet having a first flat surface and a second opposing flat surface, and a plurality of through holes. The first flat surface is in fluid communication with a reservoir that holds a target mixture that includes a target material and non-target particles. The through holes extend from the second flat surface and are fluidly coupled at the second flat surface to an orifice of a nozzle. The sheet has a surface area that is exposed to the target mixture, the exposed surface area being at least a factor of one hundred less than an exposed surface area of a sintered filter having an equivalent transverse extent to that of the sheet.