A sample scanning device operating in a working volume of 30x30x18 µm with interferometer and capacitance-based controls of displacements, is described. The xy stage uses plane mirror linear interferometers and fast phase-meters for control of displacements of precise ball-bearing stages driven by piezo flexure actuators. The stage operates with a full range bandwidth of 200 Hz, and an estimated accuracy (k=2) of 3 nm + 1E-3 L, where L/µm is the lateral displacement. A novel z-stage based on a kinematic coupling between two plates, the upper one being moved by three bimorph plates and the distance being measured by three capacitive sensor, is described. The tilt of the z-stage is kept within fractions of a microrad, leading to a full range estimated accuracy of 2 nm + 2E-3 h, where h/µm is the vertical displacement. The control bandwidth is of about 1kHz, thus allowing fast and accurate step-height measurements. In order to test the device used in a scanning probe microscope, micrometric patterned surfaces made using high resolution e-beam lithography and precise metal deposition on silicon have been imaged. Results of pitch measurements are discussed and compared with those obtained using optical diffractometry.
A sample scanning system with nanometric accuracy for quantitative SPM measurements
2001
Abstract
A sample scanning device operating in a working volume of 30x30x18 µm with interferometer and capacitance-based controls of displacements, is described. The xy stage uses plane mirror linear interferometers and fast phase-meters for control of displacements of precise ball-bearing stages driven by piezo flexure actuators. The stage operates with a full range bandwidth of 200 Hz, and an estimated accuracy (k=2) of 3 nm + 1E-3 L, where L/µm is the lateral displacement. A novel z-stage based on a kinematic coupling between two plates, the upper one being moved by three bimorph plates and the distance being measured by three capacitive sensor, is described. The tilt of the z-stage is kept within fractions of a microrad, leading to a full range estimated accuracy of 2 nm + 2E-3 h, where h/µm is the vertical displacement. The control bandwidth is of about 1kHz, thus allowing fast and accurate step-height measurements. In order to test the device used in a scanning probe microscope, micrometric patterned surfaces made using high resolution e-beam lithography and precise metal deposition on silicon have been imaged. Results of pitch measurements are discussed and compared with those obtained using optical diffractometry.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
