I’m always fascinated by Zero Insertation Force (ZIF) Sockets, but a bit scared by the price. Simple ones (DIP and SOIC) goes for a few bucks on Ebay, but the more fascinating ones (QFP, QFN, (T)SOP, BGA) either can’t be found or are very expensive. Even on the markets in Shenzhen they are 350 CNY. Remembering a post from Sparkfun about how they make their testing rigs and using the cheap PCB as construction material.

I wanted an programming socket for a QFN32 0.5mm pitch chip (STM32F103T) so I started with a footprint I used for the board itself and routed the powersupplies and programming signals to a .1″ header and connected the BOOT0/1 and !RST to their appropriate levels. Next on a different part of the PCB a 4x4cm cutout for the chip with holes on the corners; this should make it easier for the PCB manufacture the cutout. As a last step added 4 holes for screws to bolt things down and align the PCB.

As expected getting the cutout to position the chip accurate is a pain in the ass and the pcb substrate is getting really loose in no-time. I never really got a good reliable connection, let alone I successfully flashed a microcontroller with it. Probably with larger pitch IC it can work out, but this is why I guess professional ZIF sockets costs 50+ USD 😀

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