December 23, 2013

1645RT2U - Milandr radhard antifuse ROM : weekend die-shot

1645RT2U - radhard 32k*8 antifuse ROM, designed by Milandr. Die size - 8232x8973 µm.
Minimal observed half-pitch - 680nm.

After metalization etch:

Let's take a look at individual memory cells. Area of 1 cell is 91.8 µm2.

Antifuse ROM stores data by dielectric breakdown of thin oxide (17V is required in this case for reliable programming). On this photo you can see green "squares" - these are access transistors. Below/above them -in red rectangles - storage element itself. In the center of this rectangle there is an oval area, where dielectric is much thinner, and dielectric breakdown happens somewhere there.

SEM photo made using Hitachi TM3030: