# This directory contains a seal ring generator for SkyWater s8 using magic.
# Because the seal ring contains many layers that do not appear in standard
# layout editing, they are all specially implemented in the s8seal_ring.tech
# file in this directory.
#
# An example seal ring was generated by SkyWater and imported using magic's
# gdsquery.sh script.  It was then hand-edited to contain only the bottom
# quarter.  Then it was saved in .mag databases.
#
# The generator script s8_gen_sealring.py calls magic using the s8seal_ring.tech
# file, and automatically modifies the geometry to stretch to the half width
# and height of the specified dimensions.  Then the lower-left cells are
# copied and folded over the centerline to make the complete seal ring.
# The seal ring is then written out in GDS format.  Then a simplified magic
# view is generated in the usual user-facing s8 technology file, with the
# GDS_FILE property pointing to the seal ring GDS.  This layout and GDS can
# then be imported into a layout.
#
# Usage:
#
#   s8_gen_sealring.py width height target_dir [-force] [-outer]
#
# Where:
#   width = the full-chip layout width
#   height = the full-chip layout height
#   target_dir = location of the full-chip layout
#
#   -force = overwrite existing files in the target directory
#   -outer = width and height represent the seal ring outer edge, not the chip area
#
# Results:
#   Files advSeal_6u_gen.mag and advSeal_6um_gen.gds are generated and placed in
#   target_dir.  advSeal_6u_gen.mag is an "abstract" view that represents the
#   seal ring in diffusion and the nikon cross in metal1, and references
#   the advSeal_6um_gen.gds file in the same directory as a GDS_FILE property.
#