Cutting down its dependence on rival Samsung has been an ongoing process that Apple has been engaged in. The company has been able to shift to using suppliers such as Toshiba for NAND Flash and display panels made by LG and Sharp. While the actual percentage of dependence on Samsung isn’t known, we do know that right now all of the company’s A-series processors are coming from Samsung.
The deal with TSMC is believed to be for A-Series processors as well as the next-generation 20nm A-Series processor. If the deal gets done, TSMC will start delivering chips in early 2014. Last time that Apple tried to get a deal done with TSMC, rumors suggested that the company could not deliver chips that met the speed and power requirements that Apple wanted. Apparently, this is no longer an issue.
See the WSJ report here.