Does anyone know of any method of decapsulating a FCBGA chip that uses FR-4 as its exterior packaging ? I am interested in studying the internals of such chips and others as a hobby. I understand that there are companies that can perform this service but as I mentioned I would like to undertake this project as a new hobby. I would like to keep the internals completely intact including the die and all other components.

If this is not the correct place to ask a question of this nature then I would appreciate if someone could point me in the direction from where I might be able to gather a solution.

  • \$\begingroup\$ It houldn't be so easy, otherwise each manufacturer could look at the design of others \$\endgroup\$ – clabacchio Jun 11 '12 at 7:36
  • 2
    \$\begingroup\$ @clabacchio - It is quite easy. I've done it (not with FR-4, of course) in my university's lab - anyone who could manufacture an IC could take one apart and inspect it. If the manufacturer's contribution is rendered worthless just by looking at the chip, then the manufacturer is doing something wrong. \$\endgroup\$ – Kevin Vermeer Jun 11 '12 at 17:00
  • \$\begingroup\$ To quote the Mythbusters: "When in doubt, C4!" \$\endgroup\$ – user3624 Jun 11 '12 at 21:21

While I haven't done it myself, lots of people on the internet talk about depackaging various chips to see what is inside. They post photos I find fascinating.

Perhaps you could contact the people that run the following websites -- perhaps one or more of them knows how to take apart FCBGA chip packaging?

  • \$\begingroup\$ I have no experience working with them, but I found flylogic's blog to be extremely illuminating when researching chip decapsulation some time ago. There's also a nice overview of the process for the hobbyist/beginner at Sparkfun \$\endgroup\$ – Kevin Vermeer Jun 11 '12 at 17:09
  • \$\begingroup\$ @KevinVermeer: Thank you. There's some fascinating chip photos there. \$\endgroup\$ – davidcary Jun 11 '12 at 18:48
  • \$\begingroup\$ Your third link seems to describe physical removal of FR4 from a flip-chip BGA and then dissolving the remainder with fuming sulfuric acid while the others stick to normal epoxy packages...that looks like the best resource for the OP. \$\endgroup\$ – Kevin Vermeer Jun 11 '12 at 19:29

Do you REALLY mean FR-4?
FR-4 is a multi layer PCB material made of 0.25mm fibreglass layers impregnated with epoxy resin with multilayers laminated together. This sounds "unusual" as an FPGA encapsulation system.

(1) Patience and a "Dremel" with a high speed abrasive wheel (very fragile) works wonders on almost anything known to man.

(2) If you DO mean FR-4 and you don't mind some to much physical stress on the product during dismantlement then Methylene Chloride * will happily attack the epoxy.

The glass fibre is a tougher challenge but the MC epoxy attack will tend to rend it. MCV attack on FR4 is liable to be slow.

Don't expect the device to operate thereafter.

  • DO read the Methylene Chloride MSDS several times slowly (or several of them).

    Use under a water layer is recommended.

    Not breathing while using it is a good idea.

A sample Methylene Chloride MSDS
Note the use of the word "cancer".

Inhalation: Causes irritation to respiratory tract. Has a strong narcotic effect with symptoms of mental confusion, light-headedness, fatigue, nausea, vomiting and headache. Causes formation of carbon monoxide in blood which affects cardiovascular system and central nervous system. Continued exposure may cause increased light-headedness, staggering, unconsciousness, and even death. Exposure may make the symptoms of angina (chest pains) worse.

Ingestion: May cause irritation of the gastrointestinal tract with vomiting. If vomiting results in aspiration, chemical pneumonia could follow. Absorption through gastrointestinal tract may produce symptoms of central nervous system depression ranging from light headedness to unconsciousness.

Skin Contact: Causes irritation, redness and pain. Prolonged contact can cause burns. Liquid degreases the skin. May be absorbed through skin.

Eye Contact: Vapors can cause eye irritation. Contact can produce pain, inflammation and temporal eye damage.

Chronic Exposure: Can cause headache, mental confusion, depression, liver effects, kidney effects, bronchitis, loss of appetite, nausea, lack of balance, and visual disturbances. Can cause dermatitis upon prolonged skin contact.

Methylene chloride may cause cancer in humans.


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