GDSII Stream format is the standard file format for transfering/archiving 2D graphical design data. It contains a hiearchy of structures, each structure containing. Beyond that, let me say that the stream format is quite simple. I suspect that the people at Calma put a lot of thought into creating a file that. Learn files and view a list of programs that open them.

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If this record is omitted, then top-left justification and font 0 are assumed. This checksum is validated for the stored file in a second step to ensure that the GDSII file is correctly stored. The following is a list of record types.

By default the LayoutEditor keeps this number untouched. Speaking of dated, Stream Format allows records to be written out to multiple reels of tape. GDS II files were originally gile on magnetic tapes. This will tell what part of the library this record describes. GDSII is organized in a hierarchical fashion.

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.

The first two words, or four bytes, are called the “Record Header” A record can be as small as 4 bytes long. By default the Save Text as Polygon option is turned off.

The data can be used to reconstruct all or part of the artwork to be used in sharing layouts, transferring artwork between different tools, or creating photomasks. This marks the beginning of an array reference element an array of cells. The elegant architecture enables it to support today’s modern chips with their billions of polygons vdsii the simplicity enabled programmers to write code to manipulate GDSII and do things with it that the developers could not have imagined.


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However it is possible to save such large polygon in multiple blocks. End of library token.

A box must have five pairs of coordinates with the first and last points coinciding. Seems a bit odd in fromat archive Contains four bytes which specify in database units the extension of a path outline beyond the first point of the path.

In an AREF of course. The name of font 0 starts the record, followed by the remaining 3 fonts. I’ve listed the essential ones here:. In the MASK list, data types are separated from the layers witha semicolon.

Calma allowed only 64 layers and data types, but the Stream Format has room for of each. Unfortunately, when one needs to compute the actual position of the polygonal entities, one must “reverse” this nesting; for large databases this turns out to be a difficult computation to do quickly. A text or SREF element must have only one pair of coordinates.

Bit 0 leftmost specifies reflecton. This appendix omits the description of tape formatting, formar disk files and disk file images on tape and other media are now the norm [].

The third and fourth bytes contain the nunber of rows. Different layers typically represent different processing steps for exposure on separate mask plates.

A floating point number is made up of three parts: There may be from 1 to 32 ACL entries, each consisting of fie group number, a user number, and access rights. A polygon exceeding this limit will be split by default. I doubt anyone has had the chutzpah to start using it since.


By activating this option via the SetupDialog or via a macro, all text elements will be saved as polygons.

The GDSII Stream Format

A structure name may be up to 32 characters long. This means that any software for reading or writing GDSII has to be able to extract each byte and interpret the bits. Fromdefault is 3. Binary The database is binary for compactness.

SPIE Handbook of Microlithography, Micromachining and Microfabrication

Possible types and values are: It is an integer between and It is this nesting and hierarchy that allow one to describe an IC with one billion polygons using a database on the order of 5 GBytes This number must be at least 2 and not more than The following record types are either not used, not released, or are related to tape formatting: I suspect fipe the people at Calma put a lot of thought into creating a file that would be as easy to read in and parse as possible.

The decimal point of the binary mantissa is just to the left of bit 8. Save Path as Polygon Path elements with a width greater than 0 will be saved as a polygon. Fortunately, filf way the database was created enabled users to extend many of the dejure limitations while maintaining defacto compatibility with the actual architectural underpinnings.

This, along with the record length, tells the parser what to expect in the rest of the record. A negative value for width means that the width is absolute; i. A header record 2.