contact/via DRC : min enclosure on 2 opposite sides

laurent_c

Hi,

How to write a DRC check for contact/via with a minimum enclosure on at least 2 opposite side ?
For instance, a via has to be enclosed by metal by 0.01µm on 2 opposite sides and can be 0 or whatever positive value on the2 other sides.

Best regards,
Laurent

Matthias

Hi Laurent,

there is no out-of-the-box function yet, but there are several solutions based on the available features.

I hope this code explains two of them:

report("Via enclosure demo")

via = input(5)
metal = input(1)

# this ensures there is no "negative" enclosure
(via - metal).output("Via needs metal")

# select those via edges (or parts) with less enclosure
via_edges_with_less_enclosure = metal.enclosing(via, 10.nm, projection).second_edges

# Option 1:
# we know that via's are of a dimension so we can use "width"+"projection" to select
# opposite edges (here: via size = 0.2.um)
good_via_edges = via.edges - via_edges_with_less_enclosure
opposite = good_via_edges.width(0.2.um + 1.dbu, projection).polygons
solution1 = via.not_interacting(opposite)
solution1.output("Min enclosure 10nm on at least two opposite edges - solution 1")

# Option 2:
# (does not need a value for the via size):
# There is a problem if two edges with different orientation 
# touch. There is no "interact" on the same edge set yet, but
# you can use "width" with an "ignore_angle" of more than 90
# degree to detect such touching corners:
error_corners = via_edges_with_less_enclosure.width(angle_limit(100.0), 1.dbu)
solution2 = via.interacting(error_corners.polygons(1.dbu))
solution2.output("Min enclosure 10nm on at least two opposite edges - solution 2")

Best regards,

Matthias