GDSII

'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 become 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 due to higher data density. It has been claimed that the OASIS format is between 10 to 50 times more efficient than GDSII [1]. Unlike GDSII, OASIS allows to store geometries as shape arrays and does not exhibit intrinsic limitations such as the 32 bit coordinate space.
With the free tools "gds2pov" [2] and POV-Ray [3] you can easy convert GDSII data into a nicely rendered 3D view.
"KLayout" is a free GDSII viewer [4].
The sourceforge page for "layout" contains a list of various layout viewers[5].

Contents

See also

See also

★ Computer Aids for VLSI Design - Appendix C: GDS II Format by Steven M. Rubin

★ The GDSII Stream Format by Jim Buchanan

★ Ruby GDSII Library for reading, manipulating, and writing GDSII data in the Ruby programming language