Atomic-force acoustic microscopy cantilever beam contact resonance frequency tracking system

Abstract

The invention discloses an atomic-force acoustic microscopy cantilever beam contact resonance frequency tracking system, which is mainly applied to rapidly acquiring the contact resonance frequency of an atomic-force acoustic microscopy cantilever beam so as to realize quick elastic modulus imaging of an atomic-force acoustic microscopy and belongs to the field of nondestructive testing. The system has the principle of controlling a voltage-controlled oscillator to output a sine voltage signal of the resonance center frequency so as to excite a piezoelectric sensor based on a voltage signal corresponding to the resonance peak of the atomic-force acoustic microscopy cantilever beam. The system mainly comprises an effective value DC conversion circuit (RMS-DC) which is connected with a photodiode detector of the atomic-force acoustic microscopy cantilever beam, a voltage-controlled oscillator (VCO) which is connected with the piezoelectric sensor of the atomic-force acoustic microscopy,and a DSP control panel for processing the frequency signals. The DSP control panel controls the VCO to output the sine voltage signal of the resonance center frequency so as to excite the piezoelectric sensor and obtain a resonance curve. Therefore, the center frequency of the resonance curve is obtained and a rapid automatic frequency tracking system is realized.

Description

technical field [0001] The AFM cantilever contact resonance frequency tracking system is mainly used to quickly obtain the contact resonance frequency of the AFM cantilever, and then realize the rapid elastic modulus imaging of the AFM, which belongs to the field of non-destructive testing. Background technique [0002] The atomic force acoustic microscope (AFAM) technology excites the high-order vibration mode of the cantilever beam by making the cantilever beam of the atomic force microscope or the test object vibrate ultrasonically. Accurate determination of the drift of high-order resonance frequencies can well reflect the local mechanical properties of the specimen surface, such as contact stiffness, elastic constant, and near-surface defects. This technology has a very high lateral resolution (less than 10nm), which is not only suitable for the detection of surface and near-surface defects of electronic packaging solder joints, but also can measure the elastic properti...

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to solve the problem that in the traditional atomic force acoustic microscope technology, the lock-in amplifier or network analyzer is used to obtain the contact resonance frequency of the atomic force acoustic microscope cantilever beam, which leads to slow imaging of the atomic force microscope, and to provide a method for quickly acquiring atomic force Frequency Tracking System for Cantilever Contact Resonant Frequency of Acoustic Microscope

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