Line Width Optimization is a read-write DFM action designed to improve yield by increasing line and arc width to the optimal value without infringing on spacing rules.
Spacing violations occur when the distance between widened and optimal size lines to features in a different net is less than that specified by the Spacing Min parameter. In order to avoid spacing violations, a method referred to as `shaving' is used. The original line is separated into connected segments, each of which may be increased to the optimal width possible without causing spacing violations, as shown in the figure below:
Gaps between such segments are filled by line segments with a width defined by the Minimal Width parameter (referred to as Shaves). As result, the original line will be replaced with a combination of Optimal Width lines and Minimal Width lines.
Line Width Optimization operates on any layer, but is designed mainly for signal layers.
New categories were added to handle arc features in addition to lines.
When
an arc needs to be reduced in width, the connecting arcs are attached
to the thinned arc with the same radius on either end of the connection.
Arcs that need to be shaved are shaved on both sides of the arc. Genesis does not support one-sided arc reduction.
Histograms for all categories are produced.
The following attributes are produced once for each layer and
once (without layer name in the form of ...
) as a total for the checklist run:
Attribute |
Description |
...One_sided_neck_down
|
Measure count for the Shaved Conductor1 category for each
layer. |
...two_sided_neck_down
|
Measure count for the Shaved Conductor2 category for each
layer. |
...enlarged_without_shavings
|
Measure count for the Enlarged Conductor category for each
layer. |
...spacing_too_close
|
Measure count for the Not Enlarged Conductor category for
each layer. |
One_sided_neck_down
|
Total measure count for the Shaved Conductor1 category for
all layers. |
two_sided_neck_down
|
Total measure count for the Shaved Conductor2 category for
all layers. |
enlarged_without_shavings
|
Total measure count for the Enlarged Conductor category for
all layers. |
spacing_too_close
|
Total measure count for the Not Enlarged Conductor category
for all layers. |