BI-WAVELENGTH OPTICAL INTENSITY MODULATORS USING MATERIALS WITH SATURABLE ABSORPTIONS

摘要

Device and method for exposing photoresists on semiconductor wafers without using physical masks while improving significantly the time-and cost-efficiencies for the manufacturing of integrated-circuit chips. Two electromagnetic sources of different wavelengths are used as the light sources, with the one having longer wavelength functioning as the control light beam while the one with an appropriately shorter wavelength is used to eventually expose the photoresists on semiconductor wafers. Images of the desired circuit patterns are fist imposed onto the longer wavelength control light beam using, for example but not limited to, laser diode arrays, light emitting diode arrays, and devices similar to liquid crystal displays. The image-carrying control light beam interacts inside the bi-wavelength saturable absorber with the short-wavelength exposure light beam which carries initially a uniform intensity profile. The bi-wavelength saturable absorber transfers the images carried by the control light beam to the exposure light beam upon its exit from the bi-wavelength saturable absorber. The exposure light beam can then be used to expose photoresists without using any physical masks. The invention eliminates the prohibitively high front end costs associated with the design and production of large physical masks with fine spatial features sought for by the state-of-the-art integrated-circuit manufacturing processes. The invention, when combined with appropriate light sources, also improves the throughput rates for the fabrication of integrated-circuit chips by orders of magnitude, further enhancing the economic impacts.