Confocal scanning microscopy (CSM) has been used in biological application, materials science, semiconductor quality measurement and other non-destructive microscopic application. Small spot of light illuminates a sample, and a small detector that is ideally a point detector collects the reflected or transmitted light having the information of specimen. An image distribution can be reconstructed by a correlation analysis of spots with the high bandwidth. The mechanism for two-dimensional beam scanning and optical sectioning has an important role in CSM as the three-dimensional profiler. The parasitic motion of focus on the detector gives rise to the fatal distortion of an image profile named the extinction effect while using acousto-optical (AO) deflector. The intensity profile for the open loop scanning should be matched with its response for the standard. The non-linearity can be minimized with the optical sectioning or the optical probe of the closed loop control. This paper shows the mathematical expression of the light such as the extinction curve in the optical fields of system using AO deflector, the axial/lateral response experimentally when the error sources change, and the methods of optical sectioning. We propose the progressive methods for the high quality image as the following. At first, for having the corrected image, small spot and long scan range, this paper shows that the optimal design having the multi-objects can be used by choosing the unitary lens device in CSM. At second, in order to compensate for the intensity cancellation at the end profile that may be the cause of waviness for the optical image, this paper shows that it is efficient to schedule the frequency of scan. According to characteristics of the extinction curve and axial/lateral response having the error property, we can define the frequency and sensitivity of as their robustness. Finally, the axial response gives an important motive for the optical section, and the limit of object depth. The edge enhancement may be a fatal defeat to the reconstruction of image and sensitive to the conditions of specimen such as slope, irregular reflectivity, shape, etc. That means that the intensity profile for the open loop scanning method should be matched with its response to a perfect mirror as specimen, which can be minimized with the optical sectioning or the optical probe of the closed loop control.
In this paper, we present a 3-step auto-alignment algorithm for the incident angle of an ellipsometer without auxiliary equipment. The 3-step algorithm uses only a 3-axis precision stage (two rotation and one translation) for ellipsometric incident angle alignment, and consists of two incident angles and its following corrective process. The corrective process is to position the spot on the center of the detector's aperture plane, and consists of accessing and centering on the detector's aperture. In the first step, the polarizer and analyzer arm are set at a proper incident angle and the spot is centered on the detector's aperture by the corrective process. In the second step, the polarizer and analyzer arm are set at a measured incident angle and the spot is centered on the detector's aperture by the corrective process. In the third step, height error and angle errors of the specimen are calculated with the stage's angle from the first and second steps. Finally, locating the specimen stage at an errorless position completes incident angle alignment. We modeled 3-D optical paths using a homogeneous transformation matrix (HTM), and simulated the developed alignment algorithm. The results showed that the developed alignment algorithm works well. Experiment results also revealed good agreement on the simulation. The developed alignment algorithm may be applied to other alignment problems, such as tilt alignment of lithography.
12 This paper shows the mathematical expression of the light such as the extinction curve in the optical fields of system using AO deflector, and the axial/lateral response experimentally when the error sources change. We propose the progressive methods for the rejection of image extinction as the following. At first, for having the corrected image, small spot and long scan range, this paper shows that the optimal design having the multi-objects can be used by choosing the unitary lens device in confocal scanning microscopy. At second, in order to compensate for the intensity cancellation at the end profile that may be the cause of waviness for the optical image, this paper shows that it is efficient to schedule the frequency of scan. According to characteristics of the extinction curve and axial/lateral response having the error property, we can define the frequency and sensitivity of as their robustness.
12 In manufacturing a rotating-analyzer ellipsometer, error sources and calibration methods are discussed. It is important to get rid of external noise for measurement of high thickness resolution and accurate optical constant and this means that the precision of system above all is important to develop the ellipsometer. Therefore the precision design and error calibration of the optical components in ellipsometer are inevitable. We propose a PSA (polarizer-specimen-analyzer) system to manufacture a rotating-analyzer ellipsometer.
12 In this paper, we designed and made a solid immersion lens (SIL) microscope using SIL (diameter equals 1 mm, refractive index n equals 1.83). Through the real experiment, we obtained the scanned-surface image of 700 nm and 300 nm standard specimens using SIL effect (compared with it's SEM scanning picture) an analyzed the result and error of image and system. According to this paper we can assure the capability of SIL microscope and possibility of the development of high-area density, large-capacity data storage device.
12 Novel precision mechanical design for ellipsometer is developed. To develop several properties of precision ellipsometer, the kinematic coupling is used at specimen stage and connecting parts between mainframe and analyzer unit, and connecting part between mainframe and polarizer unit. Homogeneous transformation matrix describes all ellipsometer components and the process of light transmitting through ellipsometer components. Geometrical error analysis is performed in order to minimize the incident alignment errors. As a result of that, the rotational error of light source is most dominant on the error of detected signal. The error bound is +/- 0.08 degree(s) for light source. The translational errors of ellipsometer components don't affect the detected signals. We manufactured a precision ellipsometer using the above- analyzed results and kinematic coupling principle. The manufactured ellipsometer has many good properties, such as precise alignment of incident angle and low manufacturing cost and so forth.
A phase shift interferometer with an improved phase unwrapping is presented. The nanometer resolution XY stage is integrated into the standard temporal phase shifting interferometer. The nanometer resolution XY stage is used to position specimen in subpixel of CCD detector, therefore CCD detector's sampling frequency is made high. This paper presents spatial sampling of CCD and two scanning algorithms, whose simulation and experiment results are also presented. The results show that the scanning algorithms make CCD detector's sampling frequency high, and phase unwrapping is improved also.