Enhancing Metrology Dynamic Range of Speckle Micro-interferometry by Quadrature Signal Algorithm
Date Issued
2007
Date
2007
Author(s)
Wang, Han-Wei
DOI
zh-TW
Abstract
Metrology plays an important role in verifying the product quality within the industries. Due to merits such as high precision and non-contact of optics, optical metrology has long benn a major field within optical metrology. A newly developed low-cost high-precision ESPI (electronic spckle pattern interferometrty) was developed during the coruse of this research..
ESPI is a full-field, non-contact, and high resolution optical metrology technique for displacement measurement, which utilized the interference fringes induced by the speckle pattern induced by the specimen surfaces. In this thesis, ESPI was applied to evaluate the thermal deformation associated with electronic packaging. For example, the high-temperature solder joints used in a flip-chip will induce large local deformation due to the differenence in thermal expansion coefficients of various materials invoved. Combining ESPI with time-stepped quadrature phase shifting was found to effective in reducing the phase shifting errors and to eliminate the phase shifting device needed, all of which were verified to improve the measurement range within the microscopic system operating conditions. In addition, the newly developed setup used for out-of-plane displacement measurement incorporated direct correlation with phase shifting, a noise reduction filter for phase unwrapping, and Fourier transform based partial differential equation solver with an attempt to improve system accuracy and measurement speed. For image data acquisition part, the high speed CCD camera was replaced by using a traditional off-the-shelf CCD camera. It is worth noting that this replacement reduced the system cost without sacrificing the measurement speed as the exposure time was controlled by using the width of the triggering pulse and the image capture was synchronized by using the external trigger shutter mode.
With the rapid advancement of microelectromechanical system (MEMS), time-stepped quadrature phase shifting with a ESPI system implemented in this thesis was used to measure the motion of a micro-pump that was composed of platinum and parylene. The results obtained verified the system capability and metrology accuracy.
Subjects
電子斑點干涉術
熱變形量測
時進正交相移法
曝光控制
微機電量測
electronic speckle pattern interferometry (ESPI)
thermal deformation
time-stepped quedrature phase shifting
exposure time control
MEMS measurement
Type
thesis
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