Open Artwork System Interchange Standard (OASIS) is a binary file format used for specification of data structures for photomask production. It is used to represent a pattern, an interchange and encapsulation format for hierarchical integrated circuit mask layout information produced during integrated circuit design. This information is then used in the manufacture of a photomask. The name is the trademark of SEMI. It was developed by SEMI for the microelectronics/fabrication industry as a replacement for the GDSII format, which was standardly used for IC layout data exchange for more than three decades. Like GDSII, OASIS is a hardware - and software - independent binary data format. It improved by having a smaller file size than GDSII file format. The smaller file sizes may result in faster loading of OASIS files. However, due to its internal structure, increased processor capacity is needed to parse these files and to nullify performance gains conferred by smaller file size. The OASIS file format is not as common as the GDSII file format.
The OASIS files can be opened and saved with normal file features. The OASIS file format stores a layer number to each element, like polygons, paths, etc. By default, the LayoutEditor keeps these numbers untouched. There is an option to setup layer mapping. This is where combinations of layer/datatypes in the OASIS file can be mapped to a layernumber in the LayoutEditor. The OASIS file format also has the ability to save the layernames. If layernames are present, the LayoutEditor will adjust the layer setting during loading of the OASIS file. There are some OASIS releated options in the LayoutEditor. All options can be adjusted in the SetupDialog. The following options are available:
If this option is enabled, a Ctrapezoid polygon is checked before it is written. If the polygon is indeed a Ctrapezoid, it will be saved as a Ctrapezoid record which will use less disk memory than a polygon. Ctrapezoid will need marginally more computing time to handel. This option is enabled by default. Disable it if you do not have the tools to support the Ctrapezoid records or if you do not have Ctrapezoids in your design, performance will be improved.
This option is similar to the Ctrapezoid option but for normal Trapezoids. It is also by default enabled.
If this option is enabled, a compression algorithm is used to compress the files. Compressed OASIS files are not always supported by other CAD software. By default, this option is disabled.
The OASIS file format can handle circles. Circles are not a basic element inside the LayoutEditor and not supported by GDSII. Circles are stored as regular polygons instead. By activating this option, any regular polygon with more than 8 points will be saved as a circle element and not as a polygon.
If activated the layer mapping tool in the LayerManager is used. Layer and layer/datatype combinations can be stored on different layers. By default this option is disabled.
If enabled, shapes on disabled layers are ignored and not stored during an OASIS save.