Open Artwork System Interchange Standard

Open Artwork System Interchange Standard (OASIS) is a binary file format used for specification of data structures for photomask production. It's used to represent a pattern an interchange and encapsulation format for hierarchical integrated circuit mask layout information produced during integrated circuit design that is further used for manufacturing of a photomask. The standard is developed by SEMI. The language defines the code required for geometric shapes such as rectangles, trapezoids, and polygons. It defines the type of properties each can have, how they can be organized into cells containing patterns made by these shapes and defines how each can be placed relative to each other. It is similar to GDSII.

As of 2023 the cost of the standard for members of SEMI was set to $252 and non-members: US$335.