All electronic parts on a printed circuit board are designed to be able to withstand the temperatures of a reflow soldering oven. Wait, what about the black plastic integrated circuit packaging? Most plastics have a lower melting point than solder. The “plastic” IC packages clearly can’t be plastic since they would melt when exposed to the heat of reflow soldering.
So, what material are they actually made out of? It is epoxy, a thermoset plastic, rather than a thermoplastic. Therefore, it will not melt when it is overheated. More specifically, it is formulated so that high temperatures decomposition will result in charring.
20191105/DuckDuckGo what kind of plastic is used for ic packages
20191105/https://electronics.stackexchange.com/questions/217423/ics-chips-are-typically-packaged-in-what-material
broken/http://www.ti.com/en/download/qlty/SEMICONDUCTOR_PACKAGING_ASSEMBLY_TECHNOLOGY-MISC.pdf
20191105/DuckDuckGo semiconductor packaging technology misc
20191105/http://educypedia.karadimov.info/library/SEMICONDUCTOR_PACKAGING_ASSEMBLY_TECHNOLOGY-MISC.pdf
Here is some more great information on the plastic packaging and considerations for reflow soldering.
20191105/DuckDuckGo temperature range of plastic ic packaging
20191105/DuckDuckGo plastic ic package max temperature
20191105/https://www.intel.com/content/dam/www/programmable/us/en/pdfs/literature/an/an113.pdf
So what is the temperature limit of the epoxy? It depends on the formulation. Carbon-fiber reinforced epoxy composites can withstand temperatures up to 1500 degrees Celsius. If I had to guess, I would assume that double the reflow temperature (> 500 degrees Celsius) would run the risk of destroying the epoxy packaging on your printed circuit boards.
20191105/DuckDuckGo maximum temperature epoxy
20191105/https://sciencing.com/effects-high-temperature-epoxy-8590977.html