2 days ago
- USB memory sticks are manufactured starting from bare FLASH memory chips, which are screened for capacity and functionality using a probe card in a non-clean-room environment.
- Workers manually place chips onto PCBs using tools like modified chopsticks, relying on surface tension to transfer the silicon die.
- After manual placement, chips are wirebonded using an automated machine with image recognition, and operators can manually fix mis-bonded wires.
- The entire assembly before encapsulation is flexible, with thinned silicon chips and thin PCBs allowing slight flexing.
- The final product is created by overmolding with epoxy and cutting into individual pieces.
- The controller chip is likely an 8051-class CPU handling USB-to-FLASH bridging, bad block management, and error correction.