IBM has developed working logic test chips with transistors produced at 7nm. The breakthrough was made possible with EUV machines by using germanium silicon instead of silicon. The group is collaborating with Samsung and Global Foundries on the realization.
According to IBM, the breakthrough will enable chips with more than 20 billion transistors. The company claims a surface reduction of 50 percent compared to a comparable 10nm chip. The aim is to match the reduction with a 50 percent improvement in the consumption/performance ratio, IBM reports to Ars Technica.
The size of the transistors results in more economical and faster chips. For the time being, it is a test chip in which parts are manufactured at 7nm. It will be at least another two years before actual production can begin, if the chip makers continue on the path that IBM and its partners are now embarking on. It is a logic chip and not a memory chip. Logic chips are much more complex than memory chips and therefore more difficult to manufacture. This shows that the production method can be used for complex chips. IBM also uses finfets as are also used in current chip generations.
The 7nm chip is produced by using euv machines. The euv machines must follow up on current immersion lithography systems and use light with a wavelength of 13.5nm, with which smaller structures can be applied to wafers. There are doubts as to whether the euv technology will be ready in time for 7nm production. IBM tells the New York Times that it sees euv as suitable for commercial chip manufacturing, but experts see increasing the number of wafers that the euv machines can process as an obstacle. In addition to euv, IBM uses self-aligned quadruple patterning, which uses larger lithographic structures to guide molecules in certain patterns, thus building smaller structures than is possible lithographically.
The channels of the transistors are made of a germanium silicon alloy. IBM has been working with germanium silicon for some time as a successor to pure silicon. The alloy is a better conductor than pure silicon, allowing electrons to flow faster. Imec research institute also considers germanium silicon a suitable material for 7nm production.
The 7nm test chip was developed at the American SUNY research institute by the Common Platform consortium of IBM, Samsung and Global Foundries. The latter took over the chip division from IBM last year, but the group is still researching chip technologies. Intel is currently leading the way with its 14nm process, but Samsung, GlobalFoundries and TSMC are catching up. Intel was supposed to start 10nm production next year but there are reports of a delay until early 2017.