Study on nano-inprocess measurement for flexible micromachinig

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The micromechanism of which size is smaller than a few millimeters for examples micro-motor micro-liner drives, micro-pumps, etc has been developed. In recent years a variety of micromachines have been fabricated by silicon surface micromachining techniques and another new developed micromachining techniques. Accuracy of components of the micromechanism is required to be of submicrometer order. It is necessary to develop in-process measurement and evaluation techniques for the fusion micromachining in order that the efficient fabrication of finer scale form is performed.The principle of measurement is based on the optical Fourier transform and phase-retrieval method. In order to retrieve the phase information for our measurement technique, the phase-retrieval algorithm based on the logarithmic Hilbert transform and the Fourier series expansion from two Fraunhofer diffraction intensities which are related to the square of the modulus of Fourier transform of object field with and without … More an exponential density filter at the object plane is applied. Our measurement technique makes it possible to reconstruct three-dimensional form of the whole area of a workpiece which is illuminated by the laser beam from two Fraunhofer diffraction intensity distributions.In order to verify the validity of the proposed method, computer simulations of reconstruction of the fine groove model is performed. The relation between the size parameters of groove profile and the exponential density filter type is made clear. Moreover, the inverse scattering measuring system which is composed of the Fourier transform optical system and the exponential density filter optical system is developed. By using the measuring system, the measurements of the fine triangular groove with the pitch of 9.1mm and the depth of 0.4mm which is fabricated by ultra precision diamond turning is carried out. The reconstructed profile is much the same as the profile which is measured by using the conventional stylus method. It is shown that the proposed measurement method is effective for reconstructing the profile of a micrometer size workpiece without scanning probe and stylus. Less