In the design of integrated circuits, the most popular format for interchange is the Calma GDS II stream format (GDS II is a trademark of Calma Company, a wholly . Portions of the GDSII Stream Format Manual, Documentation No. B97E, Feb. , reprinted with permission of Cadence Design Systems, Inc., River. GDS II is a database file format which is the de facto industry standard for . The GDSII or Stream file format stores its information in records.
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I haven’t seen this since the days of 9 track tapes on reels, but just in case, here we go The first four bytes of a record are the header. A text or SREF element must have only one pair of coordinates. By activating this option via the setup dialog or via a macro, all saved GDS II files will be padded to this length by adding a 0 at the end of the file.
If this record is omitted, and algle of zero degrees is assumed.
GDS II (Calma GDS II)
GDSII files were originally placed on magnetic tapes. When Holes As Polygons is not selected, polygons with holes are translated as sttream polygons, the false edge segment becoming part of the polygon.
For example, if a design contains an MLIN it will be flattened. Currently, the format is owned by Cadence Design Systems. To calculate the size of a user unit in meters, divide the second number by the first.
The file was padded with NULL characters so that it was always a multiple of bytes. The first two words, or four bytes, are called the “Record Header” A record can be as small fprmat 4 bytes long. The names of the layers and its appearance in the design is not stored.
This appendix omits the description of tape formatting, since disk files and disk file images on tape and other media are now the norm .
For every hex digit shifted, the exponent is decreased by one. This page was last edited on 27 Novemberat Starts with name of the first library and is followed by the second.
This option is tormat, if the mask vendor does not accept shapes other than polygons. The actual stream file: The default value is 1. It is an integer between and 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.
The GDSII Stream format manual says that a record may be infinitely long, but frankly, I don’t see how it can get over bytes long, since the first two bytes of the record header are an unsigned integer that defines the length of the record.
Various companies including Artwork have developed their fformat gdsii binary-ascii converters for those who wish to use tools such as Perl, awk or Python to manipulate GDSII data. To calculate the size of a user unit in meters, divide the second number by the first.
There may be more than one piece of data, but the rest of the record will be of this type.
GDSII – LayoutEditor Wiki
Exactly 1 pair AREF: This means that the entire record is 4 bytes long. GDSII interpreters will either impose such a limit explicitly, or will impose an implicit limit by running out of memory during recursive operations. Square ended paths 1: The value of the text type must ge in the range of 0 to The third byte of the header is the record type also known as a “token” shown below, and the fourth byte is the data type.
The third data type is a “Two-Byte Signed Integer”.
SPIE Handbook of Microlithography, Micromachining and Microfabrication
It is a binary file format representing planar geometric shapes, text labels, and other information about the layout in hierarchical form. Table of Contents Previous streaj I’ve noticed that some OK, many stream files that were originally written to disk using more modern software also pad the file to a multiple of bytes using NULL characters.
The data can be used to reconstruct all or part of the artwork to be used in sharing gxsii, transferring artwork between different tools, or creating photomasks.
This is done by adding an additional cell to the design with the name LayerNames that contains a text elements on each layer with the layer names. No data is present. To write fixed-block sized tapes for transfer to other systems, refer to your computer system documentation.
Fromdefault is 3. GDSII is organized in a hierarchical fashion.
Cells can gssii nested with no limitation as to how deep the nesting goes though I have yet to see nesting more than 9 levels deep.