Study on nano-inprocess measurement for flexible micromachinig

尺寸小于几毫米的微机械，如微电机、微直线驱动器、微泵等已经发展起来。近年来，利用硅表面微机械加工技术和另一种新兴的微机械加工技术，已经制造出各种各样的微机械。微机构的零件精度要求达到亚微米级。为了有效地制造更精细尺寸的形状，发展熔融微加工的在线测量和评价技术是必要的，其测量原理是基于光学傅里叶变换和相位恢复方法。为了恢复相位信息，本文提出了一种基于对数希尔伯特变换和傅里叶级数展开的相位恢复算法，该算法从两个夫琅和费衍射强度中提取相位信息，这两个衍射强度与物场的傅里叶变换模的平方有关， ...更多信息 在物平面处应用指数密度滤波器。该测量技术可以从两个夫琅和费衍射强度分布重建工件在激光照射下的整个区域的三维形状，为了验证该方法的有效性，对精细沟槽模型进行了计算机模拟重建。明确了沟槽轮廓尺寸参数与指数密度滤波器类型之间的关系。研制了由傅里叶变换光学系统和指数密度滤光片光学系统组成的逆散射测量系统。利用该测量系统对超精密金刚石车削加工的螺距为9.1mm、深度为0.4mm的三角形细槽进行了测量。重建的轮廓与传统触针法测量的轮廓基本一致。实验结果表明，该测量方法在不使用扫描测头和测头的情况下，可以有效地重建微米级工件的轮廓。少

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