Samsung on Thursday said that it is on track to start high-volume production using its 3GAE (3 nm-class gate all-around early) fabrication process this quarter (i.e., in the coming weeks). The announcement not only marks the industry's first 3nm-class manufacturing technology, but also the first node to use gate-all-around field effect transistors (GAAFETs).
"Enhance technology leadership via world’s first mass production of GAA 3-nano process," a statement [PDF] by Samsung reads.
Samsung Foundry's 3GAE process technology is the company's first process to use GAA transistors, which Samsung officially calls multi-bridge channel field-effect transistors (MBCFETs).
Samsung formally introduced its 3GAE and 3GAP nodes about three years ago. When the company described its 256Mb GAAFET SRAM chip produced using its 3GAE technology, it made a number of claims. Samsung said that the process would enable a 30% performance increase, a 50% power consumption reduction, and up to 80% higher transistor density (including a mix of logic and SRAM transistors). It remains to be seen how the actual combination of performance and power consumption will play out for Samsung though.
In theory, GAAFETs have a number of advantages when compared to currently used FinFETs. In GAA transistors, channels are horizontal and are surrounded by gates. The GAA channels are formed using epitaxy and selective materials removal, which allows designers to precisely tune them by adjusting width of the transistor channel. High performance is gained via wider channels, low power via narrower channels. Such precision greatly reduces transistor leakage current (i.e., lowers power consumption) as well as transistor performance variability (assuming that everything works well), which means faster time-to-yield, time-to-market, and improved yields. Also, GAAFETs promise to reduce cell area by 20% – 30%, according to a recent presentation by Applied Materials.
Speaking of Applied, it recently described high-vacuum IMS (Integrated Materials Solution) systems meant to address a major challenge of GAA transistor manufacturing: the necessity to deposit the multi-layer gate oxide and metal gate stacks around the channels in the tiny space available. The first new IMS tool from Applied Materials can deposit gate oxide that is 1.5 angstroms thinner using integrated atomic layer deposition (ALD), thermal, plasma treatment and metrology steps. The metal gate IMS integrates dipole engineering and a variety of ALD steps.
Samsung's 3GAE, being an 'early' 3nm-class manufacturing technology, 3GAE will be used primarily by Samsung LSI (Samsung's chip development arm) and perhaps one or two of SF's other alpha customers. Keeping in mind that Samsung's LSI and other early clients of SF tend to build chips in very high volumes, expect 3GAE technology to be used rather widely, assuming that yields and performance of those products meet expectations.
Transiting to a brand-new transistor structure is generally a risk as it involves a brand-new fabrication process as well as all-new tools. Other challenges are new placement methodologies, floorplan rules, and routing rules that are introduced by all new nodes and addressed by new electronic design automation (EDA) software. Finally, chip designers need to develop all-new IP, which is expensive.