Study On Key Technologies Of Calibration Of The Lateral Spring Constant Of Micro-cantilevers

The atomic force microscopy (AFM) has been widely used in the field of manipulation and manufacturing at the micro/nanometer-scale. Micro-cantilevers, which is the core of the AFM plays a significant role. The accuracy of the lateral spring constant has a direct influence on the effect of nanometer-scale manipulation and manufacturing. In order to research the interaction force between the probe and the surface in quantity, the mechanical property of the micro-cantilevers/probe should be calibrated. The existing methods of calibrating the lateral spring constants have some shortages. A new technology was analyzed based on the existing calibration methods and the corresponding calibration system is built up.The lateral torsion force of the cantilever is measured via a balance and a wedged slope whose incline has been known, and the lateral torsion is measured by the optical lever, then the spring constant can be calculated. The relative standard deviations are less than 5%, and the results are accord with the results of finite element analysis. In addition, the basic work of tapping measurement of AFM micro-cantilevers has been done using the calibration system.The main work is as follows:1.Classified and compared the existed calibration methods of AFM micro-cantilevers lateral spring constant, and a new technology was analyzed in this paper, the force is measured by an electromagnetic compensated balance and the torsion is measured by optical lever, which improves existed methods.2. The lateral spring constant calibration system was designed and set up, including the precision positioning device of micro-cantilevers, the optical lever which is used to acquire torsion and lateral force detecting unit.3. Designed the hardware and software of the calibration system and tapping unit based on MCU of MSP430F149.4. Several kinds of micro-cantilevers were calibrated, and the lateral spring constants were compared with the results of the finite element simulation. Moreover, the experiment about measuring tapping force was completed preliminarily.