photomask

/ˈfoʊtoʊˌmæsk/
noun
  1. A stencil-like plate used in photolithography to transfer a pattern onto a surface, especially in making computer chips.
    • A single photomask can contain the design for millions of tiny transistors.
    • The engineer carefully aligned the photomask before exposing the silicon wafer.
    • The factory produces photomasks for the latest smartphone processors.