Check out the strangely curvy and loopy traces on the chip in this SD card.

In particular, the one on the bottom seems to be wavy for no reason. Are they trying to make the wires the same length or something?

I cracked it with pliers and tore it in half. Pretty interesting. Most of the thickness is a rigid black resin (?) plate. On top of that is silicon, badly chipped and spalled. Through my dissecting microscope, I can see rows and columns of short little lines. Data sectors, I guess. :-)

There's very thin PCB on top of that, a layer of what might be carbon fiber, and then more thin PCB. It has a diagonal lattice of metal, with channels carved out for the traces to run in. And then some top coat.

(I can try to get a picture with my macro lens. I really wish I could get a photo through the microscope...)

I don't know why it has this diagonal lattice. Every place there's a trace, there are two other metal curves that follow, on either side, forming a boundary of the latticework.

I'd be curious if anyone who is familiar with this stuff knows why they did it this way.

@varx Maybe it's an attempt at RF shielding?

@bcl The things that popped into my head were 1) structural support, 2) grounding, and 3) RF shielding. But I couldn't make any of those quite make sense in my head.

(I think the second PCB layer also has this pattern, by the way.)

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