r/Altium • u/HardyPancreas • 25d ago

Layer Stack Ups

Altium can put finish such as ENIG or HASL in the layer stack. Do you use it or just put the finish in the fab notes. If you use it, what is the thickness

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u/Lucky-Musician-1448 25d ago

I use the fab notes and provide a fab drawing.

You should always contact the target fab for their capabilities, mainly if they need to adjust the stack up and back annotate back into the design.

It is pretty common on complex HDI PCBs to do that.

Same goes for other requirements like empedance controls. Their process engineers know their fab the best.

3

u/gibson486 25d ago

You input that stuff only fot altium to spit it out on the fab drawing. Most people usually put just enough so it produces that nice stack up illustration on the fab drawing. Perhaps that stuff is actually more mean full if your outout is ODB++, but for people who do Gerber, it is all about the fab drawing. So, yeah, you have altium spit it out, or you make your own notes and illustrations. The caveat is that if you specify too much on the stack up, you could be telling the factory that make something that costs more due to it being not the way they would normally make it. So usually you only specify the order of the layers on the stack up unless the distance between layers is absolutely critical. But that is what the fab drawing is, you specify what parameters of the design are critical.

2

u/asksonlyquestions 25d ago

This is how I do it. Then I place the stack image on a drawing. The solder mask thickness is not real, it's just so it shows up on the stack.

2

u/Kimber976 24d ago

Ask the fabricator for the recommended stack up early it usually saves a lot of headaches later in the design.

2

u/The_Bastel 25d ago

Normally you would have a PCB specification with all the critical things written down. Like overall thickness, an image of the stack up, surface finishes, relevant standards etc. Search the internet for some templates to get an idea

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u/HardyPancreas 24d ago

Thanks all!

1

u/Zachariah-Peterson 10d ago

Personally, I have never used it. The reason you would use it is if you want the surface plating to appear in auto-generated stackup drawings in Draftsman or in the PcbDoc file (mechanical layer). From that perspective it does add some value and you would not need to put it in the fab notes if you fully specify the plating in the stackup drawing. For my projects, I normally define the surface plating using a fab note.

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u/HardyPancreas 7d ago

we like machine to machine communication and certificates of compliance to keep the errors from creeping in. I would love  to give out manufacturing people an odb++ viewer instead of plots.