Two first 20nm test chips were taped out by semiconductor foundry TSMC, one is for FPGA maker Xilinx and the other is for Global Unichip Corporation. TSMC has a stake in Global Unichip.
There are kind of a rumour-reports suggesting the Global Unichip and TSMC are working together in producing 20nm chips for Apple computers, which said to have opted TSMC as foundry partner, as a strategy of keeping an alternative to Samsung. The chips what called as A8 are said to be made in 20nm nodes for use in Apple mobile devices such as iPhone and iPad devices. In all likely, the mass production of 20nm chips from TSMC to ramp from early 2014.
20nm chips cost little less than 16nm because of no finFET process but are expensive than 28nm due to double patterning. Once the 16nm becomes mainstream the 20 nm may become a shortlived node compared to 28nm, provided the majority of fab-less vendors continue to prefer 28nm. TSMC offering 20nm to give the fables companies a competitive advantage, so that they don't move to 28nm offered by other foundries. Also IDMs may resist moving into 28nm from 45nm/65nm process. It all depends on the success of 20nm chips over 28nm in offering SoCs with real market impact. That means Apple's new iPhones and iPads made using so called A8 should sell more than previous versions. China based SMIC and UMC are fast catching up to gain the share from TSMC. Now with 20nm and FinFET successful, TSMC is in safe position to lead the market for atleast another 2/3 years.
Global Unichip Corporation said to have employed Cadence Encounter Digital Implementation System (EDI) and Cadence Litho Physical Analyzer in designing 20nm system-on-a-chip (SoC) test chip. 20nm involves extreme fine-tuning of planar transistors, where there is wrath of inconsistencies from wafer to wafer. Double patterning and pre-bug catching tools help in getting chip yields. TSMC is the masterchef in baking these chips.