Solder Mask Checks

The Solder Mask Checks action checks solder mask layers for potential manufacturability defects. Its findings are collected in categories that are detailed below. Solder mask layers are always assumed to be negative, that is, all positive features describe clearances or the absence of solder masks. This action also checks if solder paste has been deposited on all SMD pads. The action operates on a single solder mask layer per side (single top, single bottom) at a time.

This action also checks solder paste layers to detect SMDs without paste and compare the negative annular ring (gasket) of the SMD pad with the paste pad.

This action uses a solder mask layer, and the drill and external copper layers associated with it.

Tests

The following tests can be applied to solder mask layers, as listed in the Action Screen and below:

1.      Drill - reports close distances to solder mask openings of PTH/NPTH annular rings, and where NPTH touches mask.

2.      Pads - reports close distances to solder mask openings of all pads, including undrilled pads. It also reports on a special group, Gaskets, which finds width of solder mask overlap on features.

3.      Coverage - reports lines that are too close to clearances (that is, not adequately covered).

4.      Rout - reports close distances between solder mask and rout features.

5.      Bridge - reports different net pads without solder mask bridges.

6.      Sliver - reports slivers between solder mask clearances.

7.      Missing - reports missing clearances.

8.      Spacing - reports close spaces between clearances (wider than sliver).

Attributes

A summary of Feature and Component attributes used during the Solder Mask check is shown below.

Feature Attributes
 

Attribute Name

Description

.smd

This attribute should be attached to outer layer pads that are lands for SMD components. It is set by the ‘Set SMD Attribute’ Cleanup Action.

.drill

This attribute is attached to hole features in drill layers. It defines the type of the drill and is used extensively during fabrication analysis.

 

Result Attributes

 

Attribute

Description

dra_ar_pth

DRA for annular ring PTH

min_ar_pth

Minimal annular ring PTH measurement value

typ_ar_pth

Typical annular ring PTH value

dra_ar_npth

DRA for annular ring NPTH

min_ar_npth

Minimal annular ring NPTH measurement value

typ_ar_npth

Typical annular ring NPTH value

dra_ar_via

DRA for annular ring via

min_ar_via

Minimal annular ring via measurement value

typ_ar_via

Typical annular ring via value

dra_ar_smd

DRA for annular ring SMD

min_ar_smd

Minimal annular ring SMD measurement value

typ_ar_smd

Typical annular ring SMD value

dra_ar_pad

DRA for annular ring pad

min_ar_pad

Minimal annular ring pad measurement value

typ_ar_pad

Typical annular ring pad value

dra_ar_pth_pad

DRA for annular ring PTH pad

min_ar_pth_pad

Minimal annular ring PTH pad measurement value

typ_ar_pth_pad

Typical annular ring PTH pad value

dra_ar_npth_pad

DRA for annular ring NPTH pad

min_ar_npth_pad

Minimal annular ring NPTH pad measurement value

typ_ar_npth_pad

Typical annular ring NPTH pad value

dra_ar_via_pad

DRA for annular ring via pad

min_ar_via_pad

Minimal annular ring via pad measurement value

typ_ar_via_pad

Typical annular ring via pad value

dra_ar_ndrl_pad

DRA for annular ring non-drilled pad

min_ar_ndrl_pad

Minimal annular ring non-drilled pad measurement value

typ_ar_ndrl_pad

Typical annular ring undrilled pad value

dra_neg_ar_smd

DRA for negative annular ring SMD

min_neg_ar_smd

Minimal negative annular ring SMD measurement value

max_neg_ar_smd

Maximum negative annular ring SMD measurement value

typ_neg_ar_smd

Typical negative annular ring SMD value

dra_neg_ar_ndrl_pad

DRA for negative annular ring non-drilled pad

min_neg_ar_ndrl_pad

Minimal negative annular ring non-drilled pad measurement value

max_neg_ar_ndrl_pad

Maximum negative annular ring non-drilled pad measurement value

typ_neg_ar_ndrl_pad

Typical negative annular ring undrilled pad value

dra_neg_ar_pth_pad

DRA for negative annular ring PTH pad

min_neg_ar_pth_pad

Minimal negative annular ring PTH pad measurement value

max_neg_ar_pth_pad

Maximum negative annular ring PTH pad measurement value

typ_neg_ar_pth_pad

Typical negative annular ring PTH pad value

dra_neg_ar_npth_pad

DRA for negative annular ring NPTH pad

min_neg_ar_npth_pad

Minimal negative annular ring NPTH pad measurement value

max_neg_ar_npth_pad

Maximum negative annular ring NPTH pad measurement value

typ_neg_ar_npth_pad

Typical negative annular ring NPTH pad value

dra_neg_ar_via_pad

DRA for negative annular ring via pad

min_neg_ar_via_pad

Minimal negative annular ring via pad measurement value

max_neg_ar_via_pad

Maximum negative annular ring via pad measurement value

typ_neg_ar_via_pad

Typical negative annular ring via pad value

dra_coverage

DRA coverage

min_coverage

Minimal coverage

typ_coverage

Typical coverage

dra_npth2m

DRA for NPTH to mask

min_npth2m

Minimal NPTH to mask

typ_npth2m

Typical NPTH to mask value

dra_sm2r

DRA for solder mask to rout

min_sm2r

Minimal solder mask to rout

typ_sm2r

Typical solder mask to rout value

num_no_bridge

Number of no bridge distance between pads

min_sliver

Minimum sliver width

num_sliver

Number of slivers

num_smd_miss

Number of missing SMD clearances

num_pth_miss

Number of missing PTH clearances

num_via_miss

Number of missing via clearances

min_pad_to_pad

Minimum pad to pad distance

num_pad_to_pad

Number of pad to pad measurements

min_pad_to_non

Minimal pad to non-pad measurements

num_pad_to_non

Number of pad to non-pad measurements

min_non_to_non

Minimal non-pad to non-pad measurements

num_non_to_non

Number of non-pad to non-pad measurements

dra

Overall DRA of a board is the minimum of all DRAs for all categories for which a DRA is defined:

dra_sm2r, dra_npth2m, dra_coverage, dra_neg_ar_via_pad, dra_neg_ar_npth_pad, dra_neg_ar_pth_pad, dra_neg_ar_ndrl_pad, dra_neg_ar_smd, dra_ar_ndrl_pad, dra_ar_via_pad, dra_ar_npth_pad, dra_ar_pth_pad, dra_ar_pad, dra_ar_smd, dra_ar_via, dra_ar_pth, dra_ar_npth,