Joint specifications for EUV sources were first presented by ASML, Canon, and Nikon in February 2002 to accelerate source development by source suppliers, and the joint specifications have been updated periodically. The latest requirements are shown in Table 2.1, which was presented at the EUV Source Workshop in Miyazaki (Japan) on November 5, 2004.
These specifications are defined at∕after the intermediate focus (IF), which is explained in the next subsection. Table 2.2 shows how major requirements changed from 2002 to 2004. Requirements for wavelength, EUV inband power, and etendue of source output were agreed on at the workshop, but requirements for repetition frequency and maximum solid angle input to illuminator are not yet agreed on, because they depend on the tool design.
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