Apple is considering either roping in its biggest rival Samsung or PC processor manufacturer Intel for making the Apple A13 SoC for iPhone models in 2019.

The iPhone-maker is likely to stick with 7-nanometer chipset designs for 2019 iPhone and iPad processors.

"Taiwanese Semiconductor Manufacturing Company (TSMC) enjoyed the benefits of being the go-to pick for chipmaking. But the 7+ nanometer processor with 'Extreme Ultraviolet Lithography' won't be integrated by TSMC so quickly. Samsung could achieve integration sooner and win Apple's business," TechnoBuffalo reported.
The sources noted that Samsung is developing at full throttles InFO packaging technology and it has also claimed to outpace TSMC in kicking off official production of EUV 7nm+ process, set for the second half of 2018, seeking to win back orders from Apple in 2019.

It is pertinent to note that both Samsung and Apple have not worked together on a chip in almost three years - since the Apple A9 released in 2015 for the iPhone 6s and iPhone 6s Plus.
manufacturer of Apple's A-Series processors for iPhone and iPad models.

Apple migrated to TSMC when the competition and legal battles between the two tech titans increased.

The A12 chip is expected to be 7nm-based chip, and is said to have entered mass production to make its way inside three new iPhone models scheduled to be released this fall.