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tutorial:tutorial_on_epoxy_decapsulation [2014/02/03 21:46]
azonenberg [Preparation]
tutorial:tutorial_on_epoxy_decapsulation [2014/02/03 21:46] (current)
azonenberg [Decapsulation]
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 When the chip is hot enough, place a single drop of acid on the center of the package, or inside the well if it was pre-drilled. Take care not to let any spill onto the pins; this is most critical in small QFP/QFN packages where the leads will be very close to the acid. Large packages such as PDIPs, as well as leadless SMD packages (LGA/​QFN/​MLF) are significantly more forgiving in this respect. When the chip is hot enough, place a single drop of acid on the center of the package, or inside the well if it was pre-drilled. Take care not to let any spill onto the pins; this is most critical in small QFP/QFN packages where the leads will be very close to the acid. Large packages such as PDIPs, as well as leadless SMD packages (LGA/​QFN/​MLF) are significantly more forgiving in this respect.
  
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 The acid will appear colorless at first, then as it heats up bubbles will form, sometimes followed by a yellowish-white foam. As the acid finishes reacting the foam will disappear. If the acid shows no reaction or just releases a few bubbles the chip isn't hot enough. In case of very soft epoxy with a fast etch rate, the foam may turn black from package fragments. The acid will appear colorless at first, then as it heats up bubbles will form, sometimes followed by a yellowish-white foam. As the acid finishes reacting the foam will disappear. If the acid shows no reaction or just releases a few bubbles the chip isn't hot enough. In case of very soft epoxy with a fast etch rate, the foam may turn black from package fragments.
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 Immediately after the foam begins to subside, remove the chip from the tray with tweezers and rinse it with acetone over a beaker. (Be careful not to boil the chip dry; this will cause the fragments to stick to the die.) Use fairly high pressure to dislodge debris. Immediately after the foam begins to subside, remove the chip from the tray with tweezers and rinse it with acetone over a beaker. (Be careful not to boil the chip dry; this will cause the fragments to stick to the die.) Use fairly high pressure to dislodge debris.
  
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 Return the chip to heat and repeat several times. Make sure the solvent has completely baked off before adding more acid. Eventually, bond wires become visible: Return the chip to heat and repeat several times. Make sure the solvent has completely baked off before adding more acid. Eventually, bond wires become visible:
 
tutorial/tutorial_on_epoxy_decapsulation.txt ยท Last modified: 2014/02/03 21:46 by azonenberg
 
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