GDSII

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File:Silicon chip 3d.png
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 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 IC fabrication. These GDSII files were originally placed on magnetic tapes, hence the final moment of the IC design process has become known as tapeout.

As of October 2004, many EDA software vendors have begun to support a new format, 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