what covers the microcontoller?

Discussion in 'Embedded Systems and Microcontrollers' started by kyserkess, Mar 29, 2010.

  1. kyserkess

    Thread Starter New Member

    Mar 29, 2010
    1
    0
    Hi, this chip is taken from a keyboard. The microcontoller is under this black dot. What is the black dot and how do I get rid of it? Can I put the chip in the oven to melt it and all the solder off? I don't care if it damages the chip, I mainly want to see the size of the microcontoller.

    This is my picture of it:
    [​IMG]

    Thanks so much for your help.
     
  2. rjenkins

    AAC Fanatic!

    Nov 6, 2005
    1,015
    69
    The covering blob will be some form of epoxy resin.

    It will probably soften or dissolve in Acetone (nail varnish remover).

    If it works, it may take several days...
    The stuff may wash away, or it could just soften like putty so you can scrape it off.

    The only thing to do is try it!

    Acetone dissolves or damages many plastics, polished surfaces and some clothing, so be careful and put it in a very small glass or metal container with a lid.
     
  3. Markd77

    Senior Member

    Sep 7, 2009
    2,803
    594
    Or sandpaper and a dust mask :)
    It is probably between 1 and 3 mm square.
     
  4. gibbled

    New Member

    Mar 17, 2010
    1
    0
    Methylene chloride would probably do the trick given a couple of days...
     
  5. BMorse

    Senior Member

    Sep 26, 2009
    2,675
    234
    One thing you will have to remember is that the "black blob" IS the die casing for the microcontroller, by removing this you will not "see" the microcontroller, the IC die is attached direct to a PCB, and bond out wires from the IC connect directly to PCB lands. The chip is then covered with a black blob of epoxy. A technique used mostly with very high volume, cost sensitive applications, e.g. musical greeting cards.

    B. Morse
     
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