Sunday, April 11, 2010

IC decapping round 1: very first IC images

Some easy IC chips to work with are the old gold capped ceramic chips. Something like this:

This particular chip is labeled MD513 76R / 7407. Since a 7407 is just a line buffer, I can't imagine it being that complicated on silicon and it must be some military grade other chip with an obscure part number. I did find similar chips that were listed as DRAM, which seems consistent with the very regular, memory like die image. Although it took a bit of practice to figure out how to do this, you can use a heat gun to take the cap off. I tried doing this again the other day and I couldn't get the caps off. Thinking back, before I used a vice with a plastic jaw and held the chip in the end, just barley not burning it. This time I put it full in a metal vice which wouldn't release it even under extreme heat. Maybe I'll Dremel them slightly to get a small hole I can grab with pliers. In any case, this is what you get:

Well the first thing to try is to use a bright light and a magnifying glass or similar. I had a 10X objective from a projector, microscope, or something. Setup:

And an idea of the image quality you get:

You can just barely read the text on the die if you strain your eye, but probably not in that picture.
Next, a biological microscope was acquired. I seem to not have a picture of it, but later setups will anyway, and you probably used one at some point in your life or Google can help you. Anyway, you can now get pictures like this:

If you use the camera optical zoom, you can get slightly higher details and also eliminate that eyepiece ring. The biggest issue is probably that the zoom level is then a bit hard to tell. I need a standardized length object to calibrate against. Looks like this:
This was an old die I wasn't protecting well and you can see some dust on it. The electronics club is sorta the anti-cleanroom. More on how the camera was mounted, lighting and such later.
Oh and don't drive yourself mad trying to line up the pictures. I think they were from the same chip, but not entirely sure.

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