iGDSPLOT Stream Settings

The iGDSPLOT interface works by writing from the Cadence layout a GDSII "stream" file - the actual data input to the GDSPLOT plotting engine. The layout database internal layer definitions are mapped to stream layer numbers.

The Stream Settings dialog allows flexibility in the way that iGDSPLOT creates a stream file. There are three available modes:

Automatic - The required number of stream layers and data types will be generated without any other input.

Technology File - The stream settings from the attached technology file will be used.

Manual - This mode allows the user to specify a stream layer map file to use.

iGDSPLOT Stream Settings
A few other options are available:

User Skill File - The user skill file option should be used when the PCell information is needed. In this case the skill file defining the Pcell is necessary to get the Pcell information exported to the GDSII file.

User script File - The user script file option can be used when it is necessary to perform a function on the exported GDSII file before it is being piped to the gdsplot engine. One common use is to perform a union operation on each layer of the GDSII file to remove any overlapping polygons (it can be done with our Qckbool product). The new GDSII file piped to the gdsplot engine will have less polygons and therefore the plot will look better.

Stream Out GDSII File - When plotting a big chip, it may take Cadence several minutes to several hours to export a large GDSII file. If the file already exist from previous plots, it is not necessary for the Cadence Interface to export it again. For large GDSII files, this feature will reduce the overall plotting time by 50-80% percent.