2010-08-12

As a kid I remember finding marvelous glisteny material at the center of discarded microchips. I wanted to look at something man-made for this year’s SEM competition, so I sacrificed an SD card to find out what’s inside.

The outer shell popped off with a little coercion from a narrow screwdriver to reveal two microchips on a flimsy printed circuit board:

I was surprised to see that the write-protect switch doesn’t have any contact with the internal components of the card. Its position is read externally and must be respected by the card reader.

The two microchips tore of easily. The larger chip is the NAND flash memory, and the smaller chip is the SD controller:

The controller didn’t last long against a duo of needle-nose pliers:

At the center is a shiny integrated circuit:

The NAND memory chip contained a more uniform mesh that resisted crumbling, kind of like miniature rebar:

With only two hours at the SEM and other samples to explore, I only managed to take two images of the SD card. The first is a disappointingly blurry image of the NAND flash memory at ten thousand times magnification, showing a larger grid formed from fine filaments:

The other image, at only eight hundred times magnification, shows the threshold between the integrated circuit and its connections through the encapsulation: