58 results about "Out of band radiation" patented technology

According to one exemplary embodiment, a laser beam formatting module for use in a lithographic system to fabricate a semiconductor wafer comprises an aperture plate having, for example, a circular aperture and capable of being situated between a laser source and a target, and a lens assembly, in a light path between the aperture plate and the target. The laser beam formatting module can produce a substantially uniform laser beam intensity across a target during fabrication of a semiconductor wafer in a laser-produced plasma (LPP) lithographic process using, for example, extreme ultraviolet light (EUV). In one embodiment, a laser beam formatting module improves energy conversion efficiency, reduces out-of-band radiation emission, avoids heating of reflective optics, and eliminates the need for an out-of-band radiation filter.

The invention is directed to an arrangement for the suppression of unwanted spectral components (‘out-of-band’ radiation, as it is called) in a plasma-based radiation source. The object of the invention is to find a novel possibility for the suppression of unwanted spectral components in radiation exiting from a plasma-based EUV radiation source which permits a simple suppression of out-of-band radiation outside the desired EUV range without requiring costly manufacturing and adjustment of diffraction gratings. This object is met according to the invention in that a filter unit is provided between the plasma and an application location of the EUV radiation, which filter unit has at least one gas curtain comprising at least one rapidly flowing gas whose molecules have no absorption maxima for the desired EUV radiation and intensive absorption maxima for other, unwanted wavelengths that are emitted, at least in the IR region. For the purpose of generating the gas curtain, at least one slit nozzle and an efficient gas sink are arranged laterally opposite one another with respect to an optical axis of the beam bundle in order to limit the gas curtain in a spatially defined manner and to remove it again from the vacuum chambers as completely as possible.