Line Width Optimization

Line Width Optimization is a read-write DFM action designed to improve yield by increasing line width to the optimal value without infringing on spacing rules.

Shaving

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.

Special Reports

Histograms for all categories are produced.

Result Attribute

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.