Re: difference layers in Gerber file

Dear Sir:
I have question about difference layers in gerber files. I check BeagleBone Black Project gerber file. I found that some gerber file named SMC, SMS, SPC, SPS and TSLK, BSLK, ASSY, FAB.
I have found some webpage which introduces PCB assembly. I can understand the TSLK ( top screen layer) BSLK(bottom screen layer)
but what is SMC and SMS ? SPC and SPS layers?

When I use pcbnew to create new footprint for IC . How can I draw the SMC and SMS layers information?

Hope get some hits about junior question.


It will be about file name extensions renamed according to the habits of a particular manufacturer of PCBs. Some manufacturers insist on it to make it by their habit of …
For an additional fee, of course, it doesn’t matter what kind of extensions to files …"-)
SM…SolderMask? SP…Solder Paste ?

SM refers to Solder Mask, and the S and C refer to Solder-side and Component-side (Or, Bottom and Top respectively). This is an older convention that still pops up now and again.

So, your total conversion with this naming scheme would go along this route:
SMC = Top Stop Mask
SMS = Bottom Stop Mask
TSKL = Top Silkscreen
BSLK Bottom Silkscreen
SPC = Solder Paste Top
CMP (short for Component) = Top Copper Layer
SOL (short for Solderside) = Bottom Copper Layer
FAB is likely an outline (Edge_Cuts.gbr, or GKO), but with clutter and notes that your fab may not like. Using GerbV can usually help clean that up.
The ASSY file can most likely be deleted. This layer usually contains component courtyards, which don’t affect PCB manufacturing.

Thanks for your explain for difference layers.

I have question about compent footprint create. when I want to create QFN (48 pins) IC footprint. I need draw what kind of layers ?
I mean if when supply design file to factory to assembly. I need Front Copper layer , Front Skill layer, Front Solder Mask layer, Front Solder Paste layer and Front Solder Paste Stencil layer .
So all their layers need draw for QFN IC footprint ?

Hi FelixLee,

What you supply to a PCB manufacturer is your overall PCB. That means, these are files containing information of your complete board and not individual ICs. You need to create the footprint and add the IC to your board as per your own requirement. Once you’ve finalized the schematics, added footprints and routed your PCB, then you have to add Solder Mask layer, Silkscreens and so on.

Just to be clear, these files are those of a complete PCB and not each and every individual IC.

circuit board fabrication