Carl EUV
The Semiconductor Manufacturing Technology business group at Carl Zeiss and the German national metrology institute Physikalisch Technische Bundesanstalt (PTB) will be expanding their cooperation in the future to include optics metrology for EUV (extreme ultraviolet) lithography. The two institutions have signed a cooperation agreement for a further four years. Together with its Dutch partner ASML, Carl Zeiss is working on the development of EUV lithography, an innovative technology for generating integrated circuits on wafers using a wavelength of 13.5 nanometers. The lithography optics from Carl Zeiss are integrated in a wafer scanner at the facilities of the global market leader ASML. The PTB supports Carl Zeiss with high-precision measurements of EUV optical components using a new EUV beamline at the PTB’s very own electron storage ring, the Metrology Light Source (MLS). The PTB and Carl Zeiss have been working together since 1998.
The PTB provides access to the measuring facilities required for the characterisation of EUV optical components. There are already a considerable number of electron storage rings worldwide, but the modern MLS operated by the PTB can rightly claim to be the only one of its kind in Germany and one of only a handful around the world. The MLS, which produces synchrotron radiation in the spectral ranges from terahertz to EUV, has been in operation since 2008. “Our biggest strength lies in at-wavelength metrology, which our cooperation partners find particularly useful,” said Dr. Frank Scholze, who heads up the PTB workgroup. “It enables us to characterise the optical components in the EUV operating wavelength rather than just using visible light, for example. As a result, our measurements give a more direct description of the behaviour of the optical components in the production machines.”
Dr. Frank Rohmund, who heads up the metrology department at Carl Zeiss Semiconductor Manufacturing Technology, explains further: “Because we work with such extreme levels of precision, optics measurement and qualification is an absolutely crucial issue in our business. With EUV lithography, we're entering a new era of chip manufacturing: In the future, we will be providing the capabilities to create structures measuring less than 20 nanometers.” EUV lithography is therefore the path that will allow Carl Zeiss to keep Moore's Law going. It enables the continued miniaturisation of chip structures, thereby helping to meet the demands of the semiconductor industry to continue making micro chips smaller, more efficient, cheaper and more environmentally friendly. EUV is currently scheduled to move into production in the middle of the decade.
The PTB’s new EUV beamline, which is particularly suited to testing photodetectors and structured optical elements, is also helping to meet these requirements. Since the completion of the start-up phase earlier this year, the beamline has increasingly been used as a metrology system in joint EUV research projects. Significant demand from industry has also prompted the PTB to further expand its storage ring measurement capabilities. With its combination of EUV reflectometers, scatterometers and ellipsometers, the PTB will have a total of around 6,000 hours of synchrotron radiation measurement capacity available each year for EUV metrology from mid-2013 onwards.