Does TSMC produce the pure silicon themselves from silica or is the refinery done by a supplier? I suspect it's the latter, but idk. It's a very energy intensiv

Does TSMC produce the pure silicon themselves from silica or is the refinery done by a supplier? I suspect it's the latter, but idk. It's a very energy intensive process, and huge source of CO2 emissions as well because you use coal to provide carbon in order to reduce the silica and get silicon + CO2.