Jmo34 at 20:03, 24 June 2008

2008-06-24T20:03:43Z

New page

[[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.]]
'''GDS II stream format''', common acronym '''GDSII''', is a [[database]] [[file format]] which is the [[integrated circuit]] industry de facto standard for [[IC layout]] data exchange. It was originally developed by [[Calma]] for its layout design software, "Graphic Data System" ("GDS") and "GDS II". Now the format is owned by [[Cadence Design Systems]].

GDS II is a [[binary file]] format representing planar geometric shapes, text labels, and some other information - in hierarchical form. The objects are grouped by numeric attributes assigned to them including "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.

Initially, GDS II was designed as a format used to control integrated circuit [[photomask]] plotting. Despite its limited set of features and low data density, it became the industry conventional format for transfer of IC layout data between design tools of different vendors, all of which operated with proprietary data formats.

GDS II files are the final output product of the IC design cycle, and are given to IC foundries for [[Fabrication (semiconductor)|IC fabrication]]. These GDSII files were originally placed on [[magnetic tape]]s, hence the final moment of the IC design process has become known as [[tapeout]].

As of October 2004, many [[Electronic design automation|EDA]] software vendors have begun to support a new format, [[Open Artwork System Interchange Standard|OASIS]], which may replace GDSII.

With the free tools "gds2pov" <ref>For more information on gds2pov visit, http://www.atchoo.org/gds2pov</ref> and [[POV-Ray]] <ref>http://www.povray.org</ref> you can easily convert GDSII data into a nicely rendered 3D view.

With GdsViewer <ref>GdsViewer can be downloaded from http://www.gbresearch.com/gdsviewer</ref> 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]].

"KLayout" is a free GDSII viewer <ref>http://www.klayout.de</ref>.
The sourceforge page for "layout" contains a list of various layout viewers<ref>http://layout.sourceforge.net/links/index.html</ref>.

Binary GDSII files can be converted to [[ASCII]] format and vice versa<ref>GDS Utilities can convert binary GDSII files to [[ASCII]] representation, http://www.gbresearch.com/gdsutilities</ref>. There is no single accepted ASCII GDSII format.

==See also==
*[http://www.rulabinsky.com/cavd/text/chapc.html Computer Aids for VLSI Design - Appendix C: GDS II Format] by Steven M. Rubin
*[http://www.buchanan1.net/stream_description.shtml The GDSII Stream Format] by Jim Buchanan
*[http://www.rubyforge.org/projects/gdsii Ruby GDSII Library] for reading, manipulating, and writing GDSII data in the [[Ruby (programming language)|Ruby]] programming language
*[http://atchoo.org/gds2pov/ gds2pov] for generating 3D scenes of GDSII layouts to render using [[POV-Ray]]
*[http://www.gbresearch.com/gdsutilities/Reference.pdf GDSII ASCII format] used in GDS Utilities

GDSII - Revision history

Jmo34 at 20:03, 24 June 2008