Via opening with copper shade

[marce]

FYI an extract from IPC-7093

 

[FvM]

I understand, that the IPC document has been issued to suggest unequivocal terms for the various via fill techniques used in the PCB industry. Some terms are however used since long, different from the document proposals. E.g. the term "plugged", suggested for a partial fill, is been used by some major companies for a surface grinded and galvanically metallized via fill, by others for a plain via fill.

The partial via fill by liquid solder mask, as discussed by the original poster, isn't listed in this overview.

 

[marce]

Quote from post #3
"The reason is i want to give my procuct MTBF to 10years, if this is the condition(pls see the attached images), how can i assure that(10years mtbf)..Vias may get damaged due to climatic conditions"

Some more related reading:
**broken link removed**

**broken link removed**

The IPC docs are related to VIA protection, flooding a via with LPI mask may or may not give a MTBF of 10 years, you would have to provide evidence of its reliability, hence pointing out the IPC- specs etc. I was refering to this specific point.

As to flooding with LPI (liquid photo imagable) mask, there is numerous annecdotal information regarding this, we do military designs and dont cover the via with LPI mask, for reliability reasons, but have used some of the other methods mentioned.
There is some notes in some of the specs regarding it, I cant find my full spec for via protection, and as we buy printed versions (cost!) I actually have to read through the thing.
:sad: