Methods and devices for detecting a distribution of charged-particle density of a charged-particle beam in charged-particle-beam microlithography systems

摘要

Charged-particle-beam (CPB) microlithography systems are disclosed that include a device for measuring the distribution of charged-particle density in a patterned beam. By providing feedback to the CPB microlithography apparatus, the distribution of charged-particle density can be optimized for high-quality exposures. An embodiment of the device includes a pinhole diaphragm defining an aperture having a small cross-dimension compared to the transverse width of the patterned beam produced by the system. The device also desirably includes a downstream scattering-contrast diaphragm defining an aperture having a larger cross dimension than that of the pinhole aperture. A photodiode or the like is downstream of the pinhole aperture and is used for detecting charged particles transmitted by the pinhole diaphragm. A patterned beam is scanned across the pinhole aperture, and charged particles not scattered during passage through the pinhole aperture propagate to the photodiode. The distribution of charged particle density is obtained from the photodiode signal, which can be fed back to components of the CPB microlithography system.