|
|
MOSIS Technical Notes
Sub-minimum Features Not Allowed
MOSIS sometimes receives designs containing layout features that are
smaller than process specifications allow.
Mask-making tools cannot render (resolve) such images exactly, and
therefore the mask inspection equipment flags a discrepancy between
the written mask and the original data. Each discrepancy must be
reviewed and waived by MOSIS staff. The entire run is delayed while
this review takes place.
In order to avoid needless delays at the mask shop, MOSIS must insist
that the following constructs not appear anywhere in a layout file,
not even in a logo or other piece of non-circuitry.
-
Any layout feature smaller than the minimum feature size for
that layer.
-
Any spacing between features smaller than the minimum spacing
for that layer.
-
Any acute angles in polygons or wires (paths), because the acute
tip itself is a sub-minimum feature.
-
Digitized images (bit maps), even when the pixel size is above
minimum width, because each point where two pixels meet
diagonally creates an unresolveable sub-minimum region; for
example,
XXX XXX
XXX XXX
XXX XXX
XXXXXX
XXXXXX
XXXXXX
If you feel that your design requires one or more of these constructs,
you must declare this at the time of project submission so that your
case may be reviewed before it is committed to fabrication.
|
Related Links
Fabrication Schedule
Customer Support
MOSIS Products
|
|
|
