6.99 DRC fail, "solder mask aperture bridges items with different nets"

[Dmc]

I am using a bridged solder jumper, which produces a DRC error:

Have I got something out of date, or does something in the footprint library or pcbnew need fixing?

• Daniel

Application: KiCad PCB Editor

Version: 6.99.0-unknown-37a2ee7d03~148~ubuntu20.04.1, release build

Libraries:
	wxWidgets 3.0.4
	FreeType 2.10.1
	HarfBuzz 2.6.4
	FontConfig 2.13.1
	libcurl/7.68.0 OpenSSL/1.1.1f zlib/1.2.11 brotli/1.0.7 libidn2/2.2.0 libpsl/0.21.0 (+libidn2/2.2.0) libssh/0.9.3/openssl/zlib nghttp2/1.40.0 librtmp/2.3

Platform: Linux 5.4.0-109-generic x86_64, 64 bit, Little endian, wxGTK, cinnamon, x11

Build Info:
	Date: Apr 20 2022 15:09:11
	wxWidgets: 3.0.4 (wchar_t,wx containers,compatible with 2.8) GTK+ 3.24
	Boost: 1.71.0
	OCC: 7.5.2
	Curl: 7.68.0
	ngspice: 36
	Compiler: GCC 9.4.0 with C++ ABI 1013

Build settings:
	KICAD_USE_OCC=ON
	KICAD_SPICE=ON

sb-example.zip (12.7 KB)

[straubm]

This error warns you about pads/nets bridged by a soldermask without dams between pads (see below left), raising the probability of solder bridges between pads. Same applies to your case. Simply ignore it as this violation is intentional in your case.

[EDIT] Not only applies to pads. Applies to any copper attached to a net afaik.

[eelik]

@Dmc

Have I got something out of date, or does something in the footprint library or pcbnew need fixing?

That type of error report has been added in the development version and isn’t in the current stable version. Nobody has thought about this kind of footprint yet with that feature. You can ignore the error. Try the context menu on that DRC error message.

[davidsrsb]

Solder mask is typically a much coarser resolution than copper pads, so any fine pitch SMD footprint will fail this check, looking like the left hand one in @straubm example above

[Dmc]

@eelik

Nobody has thought about this kind of footprint yet with that feature. You can ignore the error. Try the context menu on that DRC error message.

OK thanks. Am quite happy to “exclude” them for now, since I know there’s nothing wrong with that footprint. I was worried that I was doing something wrong, or that I had a “useful” bug to report… it hadn’t occurred to me that it was simply a “broken for now in 6.99, but nothing serious enough to worry about” thing.

[albin]

@Dmc

or that I had a “useful” bug to report

From @eelik answer I’m not sure if this is a bug that should be reported, or not?

As @davidsrsb pointed out, there are other cases when one would knowingly design a footprint with pads so close to each other that there will be no solder mask between them.

I think it’s great tha this check has been implemented! But there should be a way to get rid of the warnings/errors if done on purpose. Is the only way currently to exclude them in the DRC? What if a polygon is drawn on the solder mask layer over these pads?

[straubm]

@albin

I’m not sure if this is a bug that should be reported, or not?

I did that. Reading the thread you can see what the devs think about the check and what was decided.

PcbNew 6.99: DRC inadvertently flags aperture bridging error for mask...

[JeffYoung]

Solder mask is typically a much coarser resolution than copper pads, so any fine pitch SMD footprint will fail this check, looking like the left hand one in @straubm example above