Patent ID: 6791095
Filing Date: 2004-09-14
Classification: H01J

Abstract:
A method of positioning a specimen situated in a scanning electron microscope environment for inspecting defects in a plurality of areas of said specimen, the scanning electron microscope providing a particle beam along an axis perpendicular to the specimen, comprising:moving said specimen in directions perpendicular to said particle beam axis to a first of said plurality of areas; sensing and moving the specimen toward a focal plane of the particle beam in a direction along the particle beam axis; suspending moving the specimen when the specimen is positioned within the focal plane proximity and the proximity of said first of said plurality of areas; scanning and inspecting the first of said plurality of areas for defects; moving said specimen from the first inspection area to a second of said plurality of areas for inspection; wherein said sensing and moving the specimen is being conducted via an optical sensing system detecting a top surface of said first of said plurality of areas under inspection relative to the focal plane and operative to generate feedback signals to adjust voltages applied to a plurality of piezoelectric actuators to expand and contract said piezoelectric actuators, wherein specimen position along the particle beam axis; wherein said plurality of piezoelectric actuators including three actuators providing a stable supporting structure for precision movements and; wherein each of said plurality of piezoelectric actuators further including a flexure system for supporting said specimen that reducing hysteresis and minimizing friction in translating the expansion and contraction of the piezoelectric actuators.