According to Taiwan's newspaper The Commercial Times, TSMC has replaced Samsung as the manufacturer of Apple's A6X chip for iPads and iPhones. We have previously reported that Unimicron should be in charge of production, but apparently TSMC is the better choice for Apple.
Samsung is the supplier of the current A6 and A6X processors which are manufactured in 32 nm process while the new chips will be made by TSMC in 28 nm. Trial production has already been set for the first quarter of this year. Apple rarely comments on the contracts it signs, so this news isn't yet confirmed.