As integrated circuit mask layouts inexorably increase in complexity, the fundamental limitations of the industry standard GDSII file format have become a bottleneck. A major weakness of the GDSII format is inefficient data representation, which leads to very large files. File sizes of tens of gigabytes are not uncommon, leading to difficulties in transmission, data integrity, and consumption of hardware resources.
The Open Artwork System Interchange Standard (OASIS) was designed by the SEMI consortium (http://www.semi.org) as a modern alternative to the GDSII standard. A draft specification (SEMI Document 3626 2003/04/23) of the OASIS format standard was circulated, and subsequently adopted with very minor changes (SEMI P39-1105). The final standard document is available from the SEMI organization.
The main objective of the OASIS standard is efficient representation of mask layout geometry, both in hierarchical and flat representations. The format makes use of a number of techniques to this end.
As a ``typical'' example, the sizes in the table below illustrate the space-saving capability of the OASIS format. This lists the size of a GDSII file, and the size of the resulting OASIS file as converted with Xic with the main available options.
| File | Size (bytes) |
|---|---|
| GDSII file | 7669760 |
| OASIS, basic | 1643804 |
| plus repetitions | 1153071 |
| plus name tables | 1067157 |
| plus compression | 816225 |