Decapping Components Hack Chat with John McMaster

What lies beneath...

Wednesday, March 10, 2021 12:00 pm PST Local time zone:
Hack Chat
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John McMaster will host the Hack Chat on Wednesday, March 10 at noon Pacific.

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We treat them like black boxes, which they oftentimes are, but what lies beneath the inscrutable packages of electronic components is another world that begs exploration. But the sensitive and fragile silicon guts of these devices can be hard to get to, requiring destructive methods that, in the hands of a novice, more often than not lead to the demise of the good stuff inside.

To help us sort through the process of getting inside components, John McMaster will stop by the Hack Chat. You'll probably recognize John's work from Twitter and YouTube, or perhaps from his website, home to beauty shots of some of the chips he has decapped. John is also big in the reverse engineering community, organizing the Mountain View Reverse Engineering meetup, a group that meets regularly to discuss the secret world of components. Join us as we talk to John about some of the methods and materials used to get a look inside this world.

  • Hack Chat Transcript, Part 2

    Dan Maloney03/10/2021 at 21:15 0 comments

    Usagi Electric (David)1:03 PM
    Thanks John and Dan for putting this one on!

    devinsbench1:03 PM
    @tubetime do you think you can sort of chip away the last layer very carefully?

    tubetime1:03 PM
    @devinsbench yes but i can't do it without scratching the die

    Miles Paulson1:04 PM
    Thank you. I will reach out

    devinsbench1:04 PM

    JohnDMcMaster1:04 PM
    @tubetime lol

    JohnDMcMaster1:04 PM
    I still have the corpse here if you want it...

    Florent1:04 PM
    Thank you @JohnDMcMaster ! It's always a pleasure to follow your twitter account.

    devinsbench1:04 PM
    Is it a test equipment corpse?

    JohnDMcMaster1:04 PM
    I can stick around for a bit more if people want to chat

    JohnDMcMaster1:04 PM
    I might just multitask a bit more

    Cool, I'll wait a bit to pull a transcript. Thanks!

    JohnDMcMaster1:05 PM
    This will probably get decapped soon:

    JohnDMcMaster1:05 PM
    A few people requested these low cost caliper (oops)

    Florent1:05 PM
    @JohnDMcMaster multitasking is great but please just don't drink nitric acid instead of your coffee

    tubetime1:05 PM

    JohnDMcMaster1:07 PM

    YouTube John McMaster

    JohnDMcMaster1:07 PM
    I'm also excited about this. I'm curious if anyone has guesses what I'm doing with that

    devinsbench1:09 PM

    MS-BOSS1:09 PM
    Exposing some photopolymer?

    Meadhbh Hamrick1:09 PM
    surface acoustic wave typification?

    JohnDMcMaster1:09 PM
    @devinsbench laser is a good guess, haven't heard that one yet (but not it)

    Antoine Bercovici1:10 PM
    I think you've been interested in recovering configuration in SPLDs for reverse engineering, is it done by simple observation or has it to be done electrically? I suppose it would be different from a OTP array and a EEPROM array?

    JohnDMcMaster1:10 PM
    I have a spare unit I'm going to try to revive (missing lamp) using a parts laser someone else has

    JohnDMcMaster1:11 PM
    Hi @Antoine Bercovici ! Yes, what you can do depends a lot on the specific technology. Sometimes for example the interface is secured or maybe even the protocol is unknown so it makes more sense to use brute force imaging to extract bits

    JohnDMcMaster1:12 PM
    Ex: EEPROM is hard to see under a microscope (usually SEM, sometimes AFM) so usually other methods are used (ex: disable security or microprobe bus)

  • Hack Chat Transcript, Part 1

    Dan Maloney03/10/2021 at 21:13 0 comments

    OK, here we go! Welcome to Hack Chat, I'm Dan and I'll be modding along with Dusan today. We're really pleased to welcome John McMaster onto the Hack Chat today to talk about decapping stuff. I'm not sure I've seen John log in yet, though - you out there, John?

    adric joined the room.12:00 PM

    Florent joined the room.12:00 PM

    Meadhbh Hamrick joined the room.12:00 PM

    Florent12:00 PM
    HI all ! No video so ?

    Meadhbh Hamrick12:00 PM

    Florent12:01 PM
    (sorry for that dumb question, newbie here)

    Boian Mitov12:01 PM
    Hello everyone :-)

    No, no video today. Just good old text

    JohnDMcMaster12:01 PM
    I'm here!

    Florent12:01 PM
    Ok fine, thanks @Dan Maloney !

    Meadhbh Hamrick12:01 PM
    is there a one to one relationship between MVRVE members and chat participants today?

    Hey John, welcome! Thanks for coming on today - can you kick us off with a little on your background?

    JohnDMcMaster12:02 PM
    Sure...Hi all! My name is John McMaster. I'm am embedded systems consultant by day and by night I explore the mysteries of what's inside computer chips.

    Thomas Shaddack12:02 PM
    also, possibility to use lasers for ablation or localized heating of acid drop. (near-IR or visible diode lasers shine through test tubes, too. CO2 is stopped by glass.)

    JohnDMcMaster12:03 PM
    I have a garage lab where I decap (open up) computer chips and also have high power microscopes to see the small circuitry

    JohnDMcMaster12:03 PM
    @Thomas Shaddack are you asking if I do this today or if I've considered it? I did get a laser recently I wanted to use for more precise and quicker silver epoxy curing

    JohnDMcMaster12:04 PM
    This would in theory let me build up wires a lot more effectively without a bonding machine

    So actually making "wires" from conductive epoxy?

    JohnDMcMaster12:06 PM
    Yeah. You can get pretty good results but it does require good hand eye coordination if you want to not short out adjacent bond pads. I steady by hand against a shelf which helps al ot

    JohnDMcMaster12:06 PM
    a lot

    JohnDMcMaster12:06 PM
    Also I do this under a microscope

    Can such wires "fly" like regular bond wires? Or do they need some kind of support?

    r0b0tsp1k3 joined the room.12:07 PM

    JohnDMcMaster12:08 PM
    I've done both. But generally its easier to attach them a short distance to either the existing wire (say if it was old/broken) or add a new one a short distance from the pad

    adric12:09 PM
    what are you using for decapping?

    Florent12:09 PM
    So you are decaping ICs yet still trying to keep them alive ?

    morgan12:10 PM
    ^ yeah! and if so how much runtime can you get?

    JohnDMcMaster12:10 PM
    Depends on the project. If you want to understand just how the chip works its usually not required and often the chip is ultimately destructively analyzed. But if I want some data out I may want to keep it alive so I can do some open heart surgery

    Usagi Electric (David)12:12 PM
    Does that mean that sometimes you can get the chip running and operating while currently decapped with the silicon visible?

    JohnDMcMaster12:12 PM
    @morgan if done properly it should not significantly harm the chip / normal lifetime

    brUh__n0mArs12:12 PM

    morgan12:12 PM
    oh neat, was thinking you'd have to gas back or something

    JohnDMcMaster12:12 PM
    @Usagi Electric (David) yup! For some rare chips I've done this and I've heard they still work years later

    devinsbench12:13 PM
    Doesn't dust collecting on the bare die ever cause capacitive problems?

    JohnDMcMaster12:13 PM
    @morgan well some special applications have hermetically sealed packages, but that's more of a harsh environment / reliability thing than the silicon immediately dying. If you are nice to it, it will be fine

    Meadhbh Hamrick12:14 PM
    what about NMOS or PMOS? sure. we pretty much only see CMOS these days, but do you ever scrape the top off old chips? how is decapping an old chip different than decapping a modern chip?

    JohnDMcMaster12:14 PM
    @devinsbench not that I've seen but I'm sure there are exceptions for high speed stuff. Usually large digital ICs...

    Read more »

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