| Main technical specification The main features and possibilities of software Results obtained on Solver-P7LS Application of Scanning Probe Microscope for quality control of a surface |
| Modern microelectronics requires quality control of elements with accuracy to tens nanometers in a plane and units nanometers on normal to it. Scanning probe microscopes are used to decide the problem. Now our company NT-MDT produces the device for the control of digital audio and video discs, magnetic and magneto-optical disks, semi-conductor and other wafers with diameter 300mm. |
| The microscope Solver-P7LS is executed on welded titanium frame with six antivibration headers. The researched sample is established on a vacuum rotary coordinate table with motorize micrometer transfers with moving on one coordinate in a plane of a sample with accuracy 1 micron and rotation in a plane of a sample with accuracy 0.001°. The microscope is equipped with an optical microscope with a video camera, which are rigidly connected to a frame of the device and aligned on a cantilever. The folding measuring head with the scanner and optic-item scheme of registration of a deflection of a cantilever places above a sample. On the free end of the scanner the cantilever is fixed. The design is executed in the way that during scanning the beam of the laser of recording system remains motionless concerning a cantilever. It is reached by introduction of special system of tracking, which is mounted in the measuring head. The beam of light reflected from a cantilever is positioned into recording system by receiver that is four-section photo diodes. The signal of unbalance in shoulders of the photo diode is proportional to change of deflection corner of a cantilever during scanning. Approach of cantilever and sample is carried out by moving of the carriage with the folding head. The device control is made by software through the electronic block with help of a workstation based on IBM - compatible computer with the special software. The computer with the processor Pentium 200, 2Gbyte HD, 32Mbyte RAM is used now. For device control the specially developed universal electronic block Solver-P7 with the large opportunities for realization of various device's modes of work is used.
Electronics and software of devices in contact mode when during scanning the measurements is made in the mode of forces of repulsion, when a cantilever push down to a sample with the given force in a range 10 -9 - 10-6H;in mode of lateral forces when the corner of gag of a cantilever is registered during scanning; in the resonant or semi-contact mode when the scanning is made by an oscillating cantilever on frequency of its resonant or forced oscillating previously established in a strip of resonant actuation of cantilever. One of possible modes for realization of this mode sometimes names as "tapping" or rapping mode. In a resonant mode the feedback scheme can support constant change of amplitude or phase of oscillation, and to be registered a profile, phase, error signal, signal on multiple harmonics; non contact mode when the scanning in a mode of an attraction between a cantilever and wafer is made; "lift" mode when during scanning the cantilever passes above a surface on the given profile, in this case it is possible to contrast the specific characteristics of a surface, such as distribution of electrical forces, forces of interaction of adsorption layers; in the mode of registration magnetic forces changing, in this case the cantilever with special, magnetic-sensible cover is used; in the mode of electrical current's registration in system conducting probe of a cantilever - sample if the force of pushing is constant, that can be measured synchronously with measurement of a profile of the surface; in the "Kelvin" mode when the electrical voltage zero between a oscillating cantilever and sample surface is measured. This voltage is used for maintenance of AC on frequency of oscillating of a cantilever equal to zero. It is a well-known method of measurement of change of work function - method of vibrating capacity or Kelvin method; in modes of scanning tunnel microscopy and spectroscopy.
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