GlobalFoundries: 14nm yields are exceeding our plans
GlobalFoundries, which started to manufacture chips using 14nm low-power early (14LPE) manufacturing technology several months ago, said on Friday that its yields exceed its original expectations. One of the world’s largest contract makers of semiconductors does not reveal its actual 14nm volumes, but since the chips are made for customers, they should meet demands of the latter.
GlobalFoundries: 14nm yields are great
“Our 14nm FinFET ramp is exceeding plan with best-in-class yield and defect density,” said Jason Gorss, senior manager of corporate and technology communications at GlobalFoundries. “The early-access version of the technology (14LPE) was qualified in January and is well on its way to volume production, meeting yield targets on lead customer products.”
Earlier this year GlobalFoundries indicated that its 14LPE yields were on par with its partner Samsung Foundry (the original developer of the 14LPE), which uses the technology to produce its Exynos 7420 system-on-chip at its fab in Austin, Texas. The SoC is used inside Samsung’s Galaxy S6, S6 Edge and S6 Edge+ smartphones. So far, Samsung has shipped tens of millions of smartphones based on the Exynos 7420 application processor, which indirectly indicates rather good yields of the 14nm process technology.
Another major client for Samsung’s 14nm FinFET LPE is Apple, whose A9 system-on-chip for the iPhone 6s and the iPhone 6s Plus will be made using the fabrication process. Analysts expect Apple to sell 80 – 90 million new iPhones by the end of the year.
Working to make 14nm yields better
GlobalFoundries and Samsung are working together in a bid to improve yields and further decrease defect density of the 14nm LPE fabrication process. While the two companies do some changes in the process flow, they tend to stay close to the original and each other in order to offer their clients complete design compatibility and performance consistency.
GlobalFoundries claims that there is a special process in place, which resembles Intel Corp.’s “Copy Exactly” methodology. The “Copy Exactly” requires matching equipment configuration, chemical purity, process recipes and a lot of other things.
“A key part of the value proposition of our partnership with Samsung is the ability to offer true design compatibility at multiple fabs,” said Mr. Gorss. “We do this through a fab synchronization process that is very similar to the ‘Copy Exactly’ methodology. Of course, we can and do make changes to our process flow as necessary, but staying close to ‘copy exact’ allows us to drive the fastest possible ramp of the technology.”
GlobalFoundries does not reveal how many wafers it processes using the 14nm fabrication technology now, but earlier this year the company indicated that a significant portion of equipment needed for commercial production of chips using 14nm FinFET process had been installed.
It is unclear what equipment GlobalFoundries uses to make 14nm chips at its Fab 8, but originally the semiconductor fabrication plant was allegedly equipped with ASML’s Twinscan NXT:1950i lithography machines. Earlier this year the company acquired new tools specifically to produce chips using newer process technologies (the list probably included lithography tools, metrology tools and a number of other things). GlobalFoundries does not reveal details about its equipment, but the best scanners it could buy in late 2014 or early 2015 were ASML’s Twinscan 1970Ci step-and-scan systems, which can process up to 250 300mm wafers per hour (up from 175wph on the NXT:1950i) and have higher precision than predecessors.
All ASML Twinscan NXT machines use immersion lithography with ultraviolet light at 193nm wavelength. Since modern process technologies are designed for 193nm immersion lithography, semiconductor manufacturers can use all ASML Twinscan NXT machines with some tweaks (to the scanners and other equipment in the fab) to manufacture chips using the latest process technologies. Moreover, all Twinscan NXT scanners are field-upgradeable to the same performance level (but not to the same level of overlay performance) as the latest NXT:1970Ci system.
While the yields of 14LPE seem to be fine, it is unknown how many wafers using the new process technology it can process per month. Theoretically, GlobalFoundries can expand production relatively quickly by upgrading its existing equipment. However, since demands of GF’s clients are unknown, it is uncertain whether it actually needs any upgrades right now. In fact, GlobalFoundries’ main customer – Advanced Micro Devices – reportedly plans to use only more advanced 14LPP [low-power plus] process technology to make its chips sometimes next year.