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GDSII stream format (GDSII), is a binary
database In computing, a database is an organized collection of data or a type of data store based on the use of a database management system (DBMS), the software that interacts with end users, applications, and the database itself to capture and a ...
file format A file format is a Computer standard, standard way that information is encoded for storage in a computer file. It specifies how bits are used to encode information in a digital storage medium. File formats may be either proprietary format, pr ...
which is the de facto industry standard for electronic design automation (EDA) data exchange of integrated circuit (IC) or IC layout artwork. It is a
binary file A binary file is a computer file that is not a text file. The term "binary file" is often used as a term meaning "non-text file". Many binary file formats contain parts that can be interpreted as text; for example, some computer document files ...
format representing planar geometric shapes, text labels, and other information about the layout in hierarchical form (two-dimensional/2D CAD file format). The data can be used to reconstruct all or part of the artwork to be used in sharing layouts, transferring artwork between different tools, or creating
photomask A photomask (also simply called a mask) is an opaque plate with transparent areas that allow light to shine through in a defined pattern. Photomasks are commonly used in photolithography for the production of integrated circuits (ICs or "chips") ...
s.


History

GDS = Graphic Design System (see DS78 Initially, GDSII was designed as a stream format used to control integrated circuit photomask plotting. Despite its limited set of features and low data density, it became the industry conventional stream format for transfer of IC layout data between design tools of different vendors, all of which operated with proprietary data formats. It was originally developed by
Calma Calma Company, based in Sunnyvale, California, was, between 1965 and 1988, a vendor of digitizers and minicomputer-based graphics systems targeted at the cartographic and electronic, mechanical and architectural design markets. In the electroni ...
for its layout design system, "Graphic Design System" ("GDS") and "GDSII". GDSII files are usually the final output product of the IC design cycle and are handed over to IC foundries for IC fabrication. GDSII files were originally written on
magnetic tape Magnetic tape is a medium for magnetic storage made of a thin, magnetizable coating on a long, narrow strip of plastic film. It was developed in Germany in 1928, based on the earlier magnetic wire recording from Denmark. Devices that use magnetic ...
. The final deadline for IC designers is still called tape-out for this reason. Objects contained in a GDSII file are grouped by assigning numeric attributes to them including a "layer number", "datatype" or "texttype". While these attributes were designed to correspond to the "layers of material" used in manufacturing an integrated circuit, their meaning rapidly became more abstract to reflect the way that the physical layout is designed. As of April 2008, many EDA software vendors have moved to the stream format
OASIS In ecology, an oasis (; : oases ) is a fertile area of a desert or semi-desert environmentGoing from GDSII to OASIS
Philippe Morey-Chaisemartin (Xyalis) // EETimes 8/4/2008
For smaller designs, GDSII continues to be used today.


GDSII utilities

As the GDSII stream format is a de facto standard, it is supported by nearly all EDA software. Besides the commercial vendors there are plenty of free GDSII utilities. These free tools include editors, viewers, utilities to convert the 2D layout data into common 3D formats, utilities to fly through a 3D version, utilities to convert the binary format to a human readable ASCII format and program libraries.Octave and MATLAB toolbox for reading and writing GDSII layout files https://sites.google.com/site/ulfgri/numerical/gdsii-toolbox


See also

* Caltech Intermediate Form (not to be confused with Crystallographic Information File) * Open Artwork System Interchange Standard (OASIS) *
EDIF EDIF (Electronic Design Interchange Format) is a vendor-neutral format based on S-expression, S-expressions in which to store electronic netlists and schematics. It was one of the first attempts to establish a neutral data exchange format for the el ...
, a vendor-neutral file format made in 1980s


Notes


References

* Clein, Dan. (2000). ''CMOS IC Layout''. Newnes. * DS78Calma. (1978). ''GDS II Graphic Design System User's Operating Manual'', First Edition 1978. Online at http://www.bitsavers.org/pdf/calma/GDS_II_Users_Operating_Manual_Nov78.pdf Retrieved Apr 21, 2020.


External links


Computer Aids for VLSI Design - Appendix C: GDS II Format
by Steven M. Rubin // Addison-Wesley, 1987

by Jim R. Buchanan, 6/11/96
GDS II Graphic Design System User's Operating Manual, First Edition 1978
// Calma Interactive Graphic Systems, November 1978. Retrieved Apr 21, 2020.
GDSII™ Stream Format Manual (B97E060), Release 6.0
// Calma, February 1987 * SPIE Handbook of Microlithography, Micromachining and Microfabrication, Vol. 1: Microlithography // Bellingham, Wash. : SPIE Optical Engineering Pr., 1997

{{Webarchive, url=https://web.archive.org/web/20121229141346/http://www.cnf.cornell.edu/cnf_spie9.html , date=2012-12-29

EDA file formats