Non-Functional Pad (NFP) Removal

Non-Functional Pad (NFP) Removal is a read-write DFM action designed to remove redundant pads from a layer in order to improve performance of subsequent actions. A pad is considered redundant if its removal will not change the electrical connectivity of a layer. There are four types of pads that are considered as non-functional; you may choose any combination to remove:

Isolated

not connected to any trace on the Affected layers. Also defined as being two pads that do not touch any other feature, and that have the same location.

Settings for Isolated pads are controlled by the ERF variable v_limit_duplicate_to_similar

Duplicate

multiple pads of the same size or smaller at the same location, usually on a drill layer.

Drilled Over

pads drilled by a drill hole that is larger than the size of the pad

Covered

pads that are fully covered by other pads or features.

The NFP Removal action may be applied to any layer. On negative layers it is possible to base the action on drawn features or an inverted representation of the layer (on copper).

      

Additional Capabilities

Convert NFPs on Negative Layers to Round Pads

The NFP Removal Action can convert NFPs (Non Functional Pads) in negative layers to round pads. This is done by replacing a full circle arc with a circle.
This procedure occurs only when the Action is in Covered mode - when the pad to be removed is fully covered by other pads or features.

   

Remove Pads that are Pierced by more than One Drill

The NFP Removal Action will now remove NFPs that contain more than one drill. This also applies where two different drill layers (one blind, one PTH) have one hole piercing the same pad. This procedure occurs only when the Action is in Isolated mode - when the pad to be removed is not connected to any trace on the Affected layers.

 

Attribute assigned to only one member of a pair

The NFP Removal Action assigns the .nfp attribute to only one pad of a pair of duplicate or covered pads.

When v_tolerance > 0 (when tolerance is in effect):
For duplicate pads, the .nfp attribute is assigned to the pad that is not aligned to the drill.
For covered pads, the .nfp attribute is assigned to the smaller pad.

Note: Prior to Genesis version 9.3, when running in HP-UX 10.x, assigning the .nfp attribute to duplicated pads caused Mark mode to assign the .nfp attribute to both pads. Thus you could not select a (duplicated or covered) pad by attribute and then delete it, because Genesis would delete both pads.
Screen Parameters

Remove / Mark NFP

Remove = the action removes all pads which fit the user definitions for NFP.

Mark = the action does not remove those pads, but attaches to them the .nfp attribute.

It is possible to further control isolated pad removal by hole type. Only pads drilled by a specific hole type will be processed.

 

Special Reports

Histograms for all categories are included into the summary report.

Result Attributes

For each layer, the following attributes are produced:

Attribute

Description

..._isolated_deleted

Number of deleted isolated features in layer

..._duplicate_deleted

Number of deleted duplicate features in layer

..._drilled_over_deleted

Number of drilled over features in layer

..._covered_deleted

Number of deleted covered features, and a total for all deleted features for all layers per category is reported

isolated_deleted

Total number of deleted isolated features

duplicate_deleted

Total number of deleted duplicate features

drilled_over_deleted

Total number of drilled over features

covered_deleted

Total number of deleted covered features

Note: An ellipsis () indicates where to insert a layer name, such as in the Result Attributes list.

For example: ...copper_balanced_added indicates that a layer name is required at the beginning of the attribute.