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I'd like to know whether flame retardant epoxy resins, the FR-4 brominated type for instance, are used in the outer molding for integrated circuits or whether it's just a plain epoxy resin. Additionally, if anyone can direct me to any literature or textbooks that rigorously cover materials of construction for circuit boards I would greatly appreciate it!

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I believe ICs use some kind of high temperature plastic, that survives 205C reflow soldering. It melts when touched long enough by a hot soldering iron, like 425F - which does not bother the solder mask, the copper on the PCB, or the PCB material itself. I read a couple of Texas Instruments datasheets and didn't see anything on the IC body material, just "lead free" and "Green" notes, see page 3

Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements for all 6 substances, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes.

Pb-Free (RoHS Exempt): This component has a RoHS exemption for either 1) lead-based flip-chip solder bumps used between the die and package, or 2) lead-based die adhesive used between the die and leadframe. The component is otherwise considered Pb-Free (RoHS compatible) as defined above.

Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame retardants (Br or Sb do not exceed 0.1% by weight in homogeneous material)

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  • \$\begingroup\$ No, it is actually epoxy. Although epoxy is technically polymer, which is often called "plastic" \$\endgroup\$
    – Maple
    Commented Jul 26, 2018 at 18:41

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