| 摘要 |
Charged-particle-beam (CPB) microlithography methods are disclosed in which exposure dose on the lithographic substrate is controlled and adjusted as required to achieve proper exposure and maximal throughput, regardless of beam-transmissivity (e.g., membrane thickness) of the reticle in use. A reticle is provided with a transmitted-current-detection window exhibiting the same beam-transmissivity and forward-scattering behavior as a non-scattering membrane portion of the pattern-defining portion of the reticle. A charged-particle illumination beam is directed at the transmitted-current-detection window of the reticle. The beam current passing through the transmitted-current-detection window and reaching the wafer stage is sensed by a sensor located at or on the wafer stage. From the obtained beam-current data, a controller calculates the beam-current density on the wafer stage and calculates and sets a corresponding exposure time for exposing the wafer with an appropriate amount of exposure energy. Lithographic exposure is performed according to the set exposure time.
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