Abstract: A laser chamber with a circuitous gas return path dissipates shock waves. In one embodiment, the laser chamber includes a heat exchanger with a large surface area that defines an aerodynamic passage through which gas circulates in the laser chamber. The passage through which the gas circulates directs shock waves away from the discharge region so that the shock waves may dissipate elsewhere in the laser chamber. In addition, the large surface area of the heat exchanger efficiently cools the thermally energetic gas within the laser chamber. In another embodiment, ancillary chambers that are fluidically coupled to the main laser chamber are provided to permit shock waves to be directed away from the discharge area and to be dissipated within the ancillary chambers. Openings to the ancillary chambers are positioned such that shock waves generated by the electrode structure of the laser chamber may propagate directly into the ancillary chamber, where the shock waves then dissipate.

Abstract: A tangential fan, configured to recirculate a lasing gas mixture, has blade members, which are twisted in a substantially helical fashion about the rotation axis of the fan. The circumferential number of blade members can be constant variable between the end flanges. The circumferential position of blade members can shift monotonically or reversibly between the two ends. A tangential fan in accordance with the invention can be made using a conventional method of brazing together individually stamped and formed blade members and hub members. Finishing processes typically include post-machining, electropolishing, and electroless nickel coating.

Abstract: A test fixture for a laser gas module offers automatic and manual testing for individual gas module components. Check or pressure relief valves are tested with an increasing pressure ramp caused by a metered gas flow into a ballast tank. Metering orifices are tested by measuring pressure change in a known volume tank as gas to or from the tank is directed through the orifice under test. The fixture includes capability to test valve logic and leakages. Test sequence and results are monitored on a computer display showing a schematic representation of both module and fixture. Manual control of module and fixture components is done via a computer graphic interface.

Abstract: A first laser light intensity detector is positioned within a stepper or scanner proximate to a reticle so that attenuation due to stepper optics has already occurred prior to the laser light impinging upon the light intensity detector. Preferably, the first light intensity detector is mounted as closed to the wafer as practical. A second light intensity detector is located at the output of the laser. The light intensity detected from the outputs of the first and second light intensity detectors, in conjunction, forms part of a feedback mechanism which adjusts the light output of the laser, during wafer fabrication, so that the light intensity detected by the first light intensity detector is an optimum value.

Abstract: In one embodiment of the invention, phosphor powder in a binder is deposited on a flat first side of a fused silica substrate. The UV output of a laser beam is reflected off an angled beam splitter so as to be incident upon a flat second side of the fused silica substrate. The phosphor is energized by the UV light transmitted through the fused silica and re-radiates a visible wavelength. The binder is selected to be opaque to UV wavelengths so that only a thin layer (10-20 microns) of the phosphor is energized by the incident UV beam. Since the energized phosphor layer against the first side of the substrate is extremely thin and flat, the energized phosphor produces a visible light which precisely corresponds to the incident UV light. The visible light may then be used to determine the characteristics of the UV beam.