A sample is mounted on a piezoelectric actuator and a cantilever provided with a probe is located thereabove. A bias voltage applying circuit supplies the sample with a potential difference V.sub.T and sends out a current signal I.sub.T representing the electric current flowing between the sample and the probe to a current detecting circuit. The current signal is converted into logI.sub.T in a logarithmic amplifier and given to a differential amplifier. A displacement detecting circuit is arranged above the cantilever for detecting the displacement of the free end of the cantilever due to the atomic force appearing between the sample and the probe and for sending a displacement signal Z.sub.TIP representing the displacement to another differential amplifier. The signals from the differential amplifiers are respectively fed to terminals of an analog switch. The analog switch selects a signal to be fed to a control circuit, which control circuit generates and transmits a signal V.sub.Z as a function of the signal it receives, thereby controlling the actuator.

An information processor comprises a plurality of probes disposed so as to face to a recording medium containing an information, and a plurality of elastic members such as cantilevers supporting the respective probes. The processor reads the information by detecting each displacement of the elastic members. For the detection of displacement, the processor has an optical system for radiating a scanning light beam to the elastic members together with an optical system for detecting a reflected light from the elastic members, or alternatively has a means for detecting each displacement individually such as optically integrated optical members or piezoelectric layers provided to the elastic members.

A cantilever displacement detection apparatus comprises a laser diode for emitting a laser beam functioning as detection beam for displacement detection based on an optical lever method, and a position sensor having two light receiving regions for outputting signals corresponding to the intensity of received light. The laser diode and the position sensor are arranged such that the light beam is passed through an objective lens and made incident slantingly on a mirror provided on a free-end portion of a cantilever and the laser beam reflected by the mirror is passed through the objective lens and made incident on the position sensor.

The resonance contact scanning force microscope includes a reflective cantilever arm which is oscillated at a high harmonic of the resonance frequency of the cantilever arm, while the probe tip is maintained in substantially constant contact with the surface of the specimen. The motion of the free end of the cantilever arm is measured, to generate a deflection signal indicative of the amount of actual deflection of the probe tip. The method and apparatus permit high speed scans and real time imaging of the surface of a specimen with a substantial reduction in noise normally arising due to tip-surface interaction and acoustic noise.

Apparatus and methods are provided for using atomic force microscopy for profiling high aspect ratio features. Probe landing techniques include scanning prior to bringing the probe into contact with the feature. In one embodiment, the probe assembly cantilever is brought into contact with the feature and subsequent scanning is used to locate the feature with the probe. In another embodiment, the probe is moved in a scanning pattern in progressively lower horizontal planes until the probe contacts the sample feature. Also described is a deconvolution technique for deconvolving the sample image and a technique for measuring the tip radius of the feature.