Friday, February 29, 2008

AMD Tests First Chips Made Utilizing Extreme Ultra-Violet Lithography

Advanced Micro Devices and IBM announced that they had produced a working test chip utilizing extreme ultra-violet (EUV) lithography for the critical first layer of metal connections across the entire chip. EUV lithography will be used for commercial production of microprocessors using 22nm process technology in about eight years time.

The AMD test chip first went through processing at AMD’s Fab 36 in Dresden, Germany, using 193 nm immersion lithography, the most advanced lithography tools in high volume production today. The test chip wafers were then shipped to IBM’s Research Facility at the College of Nanoscale Science and Engineering (CNSE) in Albany, New York where AMD, IBM and their partners used an ASML EUV lithography scanner installed in Albany through a partnership with ASML, IBM and CNSE, to pattern the first layer of metal interconnects between the transistors built in Germany. After patterning, etch and metal deposition processes, among others, the EUV device structures underwent electrical testing at AMD, with transistors showing characteristics very consistent with those of test chips built using only 193 nm immersion lithography. These wafers will receive additional metal interconnect layers using standard Fab processing so that large memory arrays can also be tested.

Previous projects utilizing EUV to produce working chip components were only “narrow field”, covering just a very small portion of the design. AMD and IBM claim successful integration of “full-field” EUV lithography into the fabrication process across an entire 22mm x 33mm AMD 45nm node test chip.

The next step in proving viability of the EUV lithography for production will be to apply it not only to metal interconnects but to all critical layers to show an entire working microprocessor can be made utilizing EUV lithography. EUV lithography will need to be fully qualified for production prior to 2016, when the 22nm half-pitch node on the International Technology Roadmap for Semiconductors is expected to be reached.

Lithography is how highly complex chip designs with millions of transistors, like microprocessors, are transferred onto the silicon wafer for the many layers required to build a chip. As chip designers continue to add functions and increase the performance of their products, making the transistors smaller and smaller makes more transistors available within a given area. How small transistors and the metal lines that connect them can be made is directly related to the wavelength of light that is used to project a chip design onto a wafer. EUV lithography uses a wavelength of 13.5nm, significantly shorter than today’s 193nm lithography techniques, allowing the traditional scaling of chip feature sizes to continue.

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