Editing GDSII

{{short description|Database file format for data exchange of integrated circuit layout artwork}}
{{Infobox file format
| name          = GDSII
| icon          = 
| logo          = 
| extension     = .gds
| owner         = [[Calma]]
| type          = [[Binary file|binary]]{{r|:0}}
| released      = {{Start date and age|1978|br=yes}}
| latest release version = 
| latest release date = 
| free          = yes
| url           = 
}}
[[Image:Silicon chip 3d.png|right|thumb|300px|A rendering of a small GDSII [[standard cell]] with three metal layers ([[dielectric]] has been removed). The sand-colored structures are metal interconnect, with the vertical pillars being contacts, typically plugs of tungsten. The reddish structures are polysilicon gates, and the solid at the bottom is the crystalline silicon bulk.]]

'''GDSII stream format''' ('''GDSII'''), is a binary [[database]] [[file format]] which is the de facto industry standard for [[electronic design automation|electronic design automation (EDA)]] data exchange of [[integrated circuit|integrated circuit (IC)]] or [[IC layout]] artwork.<ref name=":0">{{Cite web |title=All About Calma's GDSII Stream File Format |url=https://www.artwork.com/gdsii/gdsii/ |access-date=2022-05-26 |website=www.artwork.com}}</ref> It is a [[binary file]] 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]]s.

== History ==
GDS = Graphic Design System (see [GDS78])

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]] 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 [[Fabrication (semiconductor)|IC fabrication]]. GDSII files were originally written on [[magnetic tape]]. 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 [[Integrated circuit layout|physical layout]] is designed.

As of April 2008, many [[Electronic design automation|EDA]] software vendors have moved to the stream format [[Open Artwork System Interchange Standard|OASIS]], which replaced GDSII.<ref name="eetimes-oasis-08">[http://www.eetimes.com/design/eda-design/4018771/Going-from-GDSII-to-OASIS Going from GDSII to OASIS], Philippe Morey-Chaisemartin (Xyalis) // EETimes 8/4/2008</ref> 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,<ref>LayoutEditor, a free GDSII editor http://www.layouteditor.net</ref><ref>"KLayout" is a free GDSII, LEF/DEF, OASIS, Gerber, DXF, CIF editor with DRC http://www.klayout.de</ref><ref>Glade, a free GDSII, LEF/DEF editor http://www.peardrop.co.uk/glade {{Webarchive|url=https://web.archive.org/web/20130327030431/http://www.peardrop.co.uk/glade/ |date=2013-03-27 }}</ref> viewers,<ref>"nanoViewer" is a free GDSII viewer, {{Cite web |url=http://www.wxnanotech.com/ |title=Archived copy |access-date=2017-10-09 |archive-date=2012-01-19 |archive-url=https://web.archive.org/web/20120119053116/http://www.wxnanotech.com/ |url-status=bot: unknown }}</ref> utilities to convert the 2D layout data into common 3D formats,<ref>gds2pov easily convert GDSII data into a nicely rendered 3D view. http://www.atchoo.org/gds2pov</ref><ref>With GdsViewer tool, any portion of GDSII artwork can be exported to 3D [[VTK]] file. The latter can be viewed and manipulated with [[VTK]] compatible viewers, e.g. [[ParaView]] http://www.gbresearch.com/gdsviewer</ref> utilities to fly through a 3D version,<ref>{{Cite web |date=2017-06-12 |title=GDS3D |url=https://sourceforge.net/projects/gds3d/ |access-date=2023-12-12 |website=SourceForge |language=en}}</ref> utilities to convert the binary format to a human readable ASCII format<ref>GDS Utilities can convert binary GDSII files to ASCII representation, http://www.gbresearch.com/gdsutilities</ref> and program libraries.<ref>Ruby GDSII Library for reading, manipulating, and writing GDSII data in the [[Ruby (programming language)|Ruby]] programming language http://www.rubyforge.org/projects/gdsii {{Webarchive|url=https://web.archive.org/web/20071024204036/http://rubyforge.org/projects/gdsii |date=2007-10-24 }}</ref><ref>Python GDSII Library for creating and manipulating GDSII files with [[Python (programming language)|Python]] http://gdspy.sourceforge.net/index.html {{Webarchive|url=https://web.archive.org/web/20150402151651/http://gdspy.sourceforge.net/index.html |date=2015-04-02 }}</ref><ref>Octave and MATLAB toolbox for reading and writing GDSII layout files https://sites.google.com/site/ulfgri/numerical/gdsii-toolbox</ref>

==See also==
*[[Caltech Intermediate Form]] (not to be confused with [[Crystallographic Information File]])
*[[OASIS (Open Artwork System Interchange Standard)]]
*[[EDIF]], a vendor neutral file format made in 1980s

==Notes==
{{reflist}}

==References==

<cite id=Clein2000>* Clein, Dan. (2000). ''CMOS IC Layout''. Newnes. {{ISBN|0-7506-7194-7}} </cite><br>
<cite id=CalmaGDSopman1978>* [GDS78] Calma. (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. </cite>

==External links==
*[http://www.rulabinsky.com/cavd/text/chapc.html Computer Aids for VLSI Design - Appendix C: GDS II Format] by Steven M. Rubin // Addison-Wesley, 1987
*[http://www.buchanan1.net/stream_description.html The GDSII Stream Format] {{Webarchive|url=https://web.archive.org/web/20160616215711/http://www.buchanan1.net/stream_description.html |date=2016-06-16 }} by Jim R. Buchanan, 6/11/96
*[http://www.bitsavers.org/pdf/calma/GDS_II_Users_Operating_Manual_Nov78.pdf GDS II Graphic Design System User's Operating Manual, First Edition 1978] // Calma Interactive Graphic Systems, November 1978. Retrieved Apr 21, 2020.
*[http://bitsavers.informatik.uni-stuttgart.de/pdf/calma/GDS_II_Stream_Format_Manual_6.0_Feb87.pdf 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, [http://www.cnf.cornell.edu/cnf_spie9.html 2.9 Appendix: GDSII Stream Format] {{Webarchive|url=https://web.archive.org/web/20121229141346/http://www.cnf.cornell.edu/cnf_spie9.html |date=2012-12-29 }}
*[http://boolean.klaasholwerda.nl/interface/bnf/gdsformat.html Details of GDSII format including illustrations]

[[Category:EDA file formats]]