Summer Fun   1 comment

(This post is dedicated to “Uncle Al” Schwartz)

There has been a lot of activity over the summer (including some new members to introduce). All our students have worked hard to generate data, and they all made significant progress in their projects, which we hope to post shortly. Right now, however, our lab is taking a well-deserved vacation before the academic year begins anew.

As it happened, there was a short period of time available to have some fun with chemistry, and we have been decapsulating computer chips found in discarded electronic devices (broken cell phones, mostly). We will post some images when our camera gets back from the repair shop.

The various recipes for decapsulating chips can be readily found, so we won’t get into too many details, but it is worth discussing lab safety. Our lab is a general-purpose space; one room is dedicated to bacterial/cell/tissue culture, and so has all the equipment and supplies commonly found in a ‘wet chemistry’ lab: glassware, for example. We also have a standard fume hood (distinct from our sterile culture hood) and chemical storage facilities.

Finally, we have lab experience. This cannot be overstated. Without knowing proper techniques and using the right tools, transferring 98% Nitric Acid and 98% Sulfuric Acid into a small heated reaction vessel would likely result in severe injuries. And we also know proper methods for disposing of hazardous waste. We aren’t chemists, but we know how to safely handle hazardous materials- liquid Nitrogen is another example. Even so, it’s a bracing experience to receive delivery of and unpack a bottle of 98% Nitric Acid.

So, shortly before vacation there was time to do something fun, and since we already had a few interesting devices like the CD/DVD optical head and hard drive read/write head we posted photos of alredy, we thought we’d give decapsulation a try and see what happens. A week to order the chemicals and some specialized supplies (the ability to essentially pick up the phone and order hazardous chemicals is a major ‘perk’ of working in a lab), and we were all set up.

If the chip is directly bonded to the printed circuit board, we first detach the chip with 98% sulfuric acid at 130 °C for 4 hours. The epoxy/resin/packaging surrounding the chip itself is removed with 98% Nitric acid at 80 °C for 4 hours, and after rinsing with Methanol, we have only the chip, the gold bonding wires, a heat sink if there is one, and the pins (if there are any) connecting the chip to the PCB. We aren’t interested in reverse-engineering with the chip (Flylogic Engineering and other groups do some amazing things), so we don’t worry about detaching all the Gold bonding wires- although we do extract them from the waste stream.

Seeing what modern wafer/chip technology can construct, up close and in the ‘raw’, so to speak, is fantastically humbling. What’s amazing is how small these are- we have some that are barely 1mm on a side. One has structures that look like ring resonators (inductors for a resonant circuit), while others are models of regularity (memory chips). They are little slivers of a perfect silicon crystal overlaid with densely packed metallic microscopic circuits, often 3 or 4 levels deep.

See you in the Fall!


Posted August 3, 2012 by resnicklab in Physics, pic of the moment, Science

One response to “Summer Fun

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  1. As always, great stuff! I absolutely love that you emphasized adding value. The live link tip is extremely helpful. I once tried to reference a tool (completely unaffiliated to myself or any company I worked for, in fact bordered on a competitor) to answer a specific comment post and got myself blocked from that blog

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