The Year of The Dragon

Hey folks,
It´s Chinese New Year and moreover it is the Year of the Dragon! What could be more fitting than finding the right #silicondoodle for this occasion?
Yes, a fire-spitting dragon was placed by some mask designers on a 256MB DDR RAM module from Nanya (NT256D64S88). The IC (NT5DS32M8AT) was obviously manufactured by IBM in 2001 as marked on the silicon die. It seems that the code name of the project was DRACO - hence the little dragon on the chip.
My challenge while hunting #silicondoodles: I often encounter the problem that dies are coated with polyimide which is used to protect the die during assembly of the chip. This layer is not easily removed and while aggressive solutions like very high temperature, strong acids, or chemical bases can remove such layers, these methods usually also attack the silicon structure leading to poor overall results, e.g. via severe discoloration.
Today, I am showing how to remove such coatings by submerging the silicon die to boiling DMSO (Dimethylsulfoxide). As DMSO has a nasty odor, I am doing parts of the experiment outdoors to avoid any hazards.
After 20 min in boiling DMSO (around 190°C), the coating could simply be wiped off the die, revealing the great Year-Of-The-Dragon doodle.
In this video, I am also applying for the first time my new metallurgical microscope set-up: the combination of a 60x objective (before, I had only 40x) and a 2x optical zoom (only digital zoom previously), leading to straight 120x magnification.
Enjoy and Happy Chinese New Year!
CPU Duke
Chapters
00:12 The Nanya DDR RAM module
00:44 Removing the ICs from the module
01:20 Decapping the memory IC
02:14 The problem: Polyimide coatings
02:50 The solution: Dimethylsulfoxide as solvent
04:22 The experiment: 20 min @ 190°C
05:55 Microscope investigation
06:22 Draco the Dragon
06:50 Happy Chinese New Year
Music
Song: Sappheiros - Awake
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[@cedric0850]

Great video!, dont forget to wear gloves! BTW, Nanya is actually Taiwanese!

[@PizzaGodOneMillion]

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