Initially, GDSII 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.
It was originally developed by Calma for its layout design software,
"Graphic Data System" ("GDS") and "GDSII". Now the format is owned by
Cadence Design Systems.
GDS II files are usually the final output product of the IC design
cycle and are given to IC foundries for IC fabrication. GDS II files
were originally placed on magnetic tapes. This moment was fittingly
called tape out though it is not the original root of the term.
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 October 2004, many EDA software vendors have begun to support a
new format, OASIS, which may replace GDSII.
No comments:
Post a Comment