wafer.space Community - I didn't mean from design, I meant as QA

Essen

But if you are interested I can send you the design files.

Though I will need to wait until I get some quarter slot dies back for knowing for sure if the PCB dimensions are even correct.

I can get access to SEM

3:32 p.m.

not sure what your needs are though, to understand how involved helping on that front would be

3:32 p.m.

actually I can access FIB/SEM

nmz787

I can get access to SEM

Oh wow, lucky you. That would be totally overkill for doing the PCBs QA, but it might prove insepsensible down the line as a solution of last resort for diagnosing why the flex pcb's bonds are failing. Do you mind if I reach out to you again in the future if this ever happens ?

Sure

Tim 'mithro' Ansell

@Essen - Maybe @carlfk knows someone with a SEM that could get you some images or something?

Ehhh this is optical resolution tier, it's nominally 11μm thick copper.... Any absolute line width deltas from etching process control are on top anyways and can be swept together with the question of where the boundary is on an optical microscopy image.

nmz787

actually I can access FIB/SEM

You're getting a few of the FC01 test dies from W.S. Run2 of you want to see how the bond pad and nearby passivated TopMetal traces are vertically/in cross section, if you can/want to?

namibj

You're getting a few of the FC01 test dies from W.S. Run2 of you want to see how the bond pad and nearby passivated TopMetal traces are vertically/in cross section, if you can/want to?

I think @Essen has the interest, i was just offering the FIB/SEM service, assuming it was relatively low effort (i.e. get a couple pictures)

nmz787

I think @Essen has the interest, i was just offering the FIB/SEM service, assuming it was relatively low effort (i.e. get a couple pictures)

I drew that GDS. And I essentially told @Essen the bond layout and the overall structure of the particular idea of these flat flex boards.

I actually didn't see the GDS

4:45 p.m.

I only jumped into the conversation after seeing Tim mention SEM

4:45 p.m.

I suppose I didn't read backstory enough

nmz787

I actually didn't see the GDS

It's very simple

namibj

You're getting a few of the FC01 test dies from W.S. Run2 of you want to see how the bond pad and nearby passivated TopMetal traces are vertically/in cross section, if you can/want to?

So you're asking about alignment between layers under a pad?

nmz787

So you're asking about alignment between layers under a pad?

Pretty sure this has all the description. Basically it's just top metal and pad openings and where needed slots for top metal. Metal5 = top metal

5:00 p.m.

The big question is also how the vertical cross section is around a pad and notably I think also where there's a slot in top metal within pad area.

For metallization buildup to form electroless pillars or worst case use diodes against substrate to electroplate (though the classic way wouldn't work unless you use some kind of like photodiode current to clamp the pad-to-GND diode at zero volt despite current flowing into the pad and out of the substrate GND tap) a metal bump onto the pads so that the anisotropic conductive film can be squished by the pads and not squished by mere flat flex traces nearby the overlap passivated top metal, because I at least am not too confident the ACF's nickel spheres won't crash through the silicon nitride passivation.