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.
|Published (Last):||3 October 2010|
|PDF File Size:||4.28 Mb|
|ePub File Size:||10.33 Mb|
|Price:||Free* [*Free Regsitration Required]|
The third byte is the record type. The size, in layout units, for the text in the exported design. Information about external data can be found in the CustomPlus User’s Manual. GDSII further employs user units in terms of number of user units to a meter.
All About Calma’s GDSII Stream File Format
The third byte of the header is the record type also known as a “token”. Since four byte signed integers are used to describe a coordinate then the integer coordinates can range from from minus 2 31 to plus 2 31 The data fformat be used to reconstruct all or part of the artwork to be used in sharing layouts, transferring artwork between different tools, or creating photomasks.
It can be used to gdsij the file with common checksum checkers like sha1sum. After the length record follows a record type and a data type byte. An example MASK list looks like this: Library name record 4. The remaining 7 bytes are the mantissa, with a binary point to the left of the most significant figure.
Exactly 3 pairs 1: The first two numbers in brackets are the record type and the last two numbers in brackets are the data type see the table above. Despite its limited set of features and low data density, it became the industry conventional format fromat transfer of IC layout data between design tools of different vendors, all of which operated with proprietary data formats.
The basic unit of measurement is fomat nanometer 10 -9 meter. End of library token An example of a common record order see below for record descriptions follows: The decimal point of the binary mantissa is just to the left of bit 8.
Two-byet signed integer 2. For Layer Editor options, see Defining Layers. This marks the beginning of a box element. This record must be present if any of the 4 fonts have a corresponding gcsii definition file.
SPIE Handbook, Volume 1: Microlithography, Section
To convert scale-independent text elements as well, select a non-zero default text size value for this option in the setup. There are values for such things as the beginning of a structure, the beginning of a boundary, the end of a rormat, and so on. If new layers are added, the importer saves the revised layer definition file to disk. Values are 0, 3, 4, 5, and Gdsiii this record is omitted, then top-left justification and font 0 are assumed.
The first is “No data present”.
GDS II (Calma GDS II)
Streamm its limited set of features and low data density, it became the industry’s default format for transfer of IC layout data between design tools of different vendors, all of which at that time operated with often strram and proprietary data formats. This is another artifact of the 16 bit words that the stream file format assumes.
The third point locates a position which is displaced from the reference point by the inter-row spacing times the number of rows.
This information is used only when reading the data into a new library. The first four bytes of a record are the header. This limit can be set via the setup dialog or via a macro. You can tell how many pieces of data are in the record by knowing the number of bytes in the record and the size of the data type. The third data type is a “Two-Byte Signed Integer”. Four-byte signed integer 3.
All other bits are currently unused and must be cleared to 0. This number must be at least 2 and not more than Contains four bytes which specify in database units the extension of a path outline beyond the first point of the path. If it is set, then reflection about the X axis is applied before angular rotation. The second is the size of a database unit in meters. Objects contained forkat a GDS II file are grouped by assigning numerical attributes to them including “layer number”, “datatype” or “texttype”.
Tsream string must adhere to CDOS file name conventions for length and valid characters, and may contain file extensions such as “. The third and fourth bytes contain the nunber of rows. It is stored in twos complement format, with the most significant byte first. The fifth through last bytes of a record are data.
This enables you to define the maximum number of vertices allowed for one polygon. This marks the beginning of a node. This is the one that seems to have never been used, so I’ll describe the eight byte real in a bit more detail. Each record type must have the specified data type.
This is required for Filtered format, and is present only in a Filtered Stream file. For AREFs, the entire array lattice is reflected, with the individual array elements riidly attached.