New chromatic confocal microscope for full-field microurface measurement
Date Issued
2009
Date
2009
Author(s)
Huang, Shun-Yang
Abstract
A chromatic confocal microscopic profilometer for full-field three-dimensionalicro surface measurement was developed using innovative multi-wavelength lightorrelation. Micro/nano structures patterned on the substrate and fabricated by the2R (Roll-to-Roll) nanoimprint processes are usually having a smooth andow-reflective surface which is not easily measured by the existing optical orontacted methods. It was an extremely difficult task to achieve an effective 3-Drofile reconstruction on this kind of micro component by using a traditional confocalicroscope. In this paper, a multi-wavelength confocal measurement methodmploying the focusing cross correlation between three LED color (Red, Green andlue) lights was introduced to measure micro structures. A compact chromaticonfocal microscopic probe was developed by integrating a white light sourcebtained by mixing the LED light sources and a coaxial confocal optical configurationith a 3-chip CCD camera for individual light sensing. A curve-fitting functionetween the profile depth and the multi-color focusing correlation was established by system calibration with a reference to an accurate laser interferometer. To attest theeasurement performance, a calibrated reference target having micro-triangulartructures was fabricated and measured by the developed methodology. From analysisf the measurement results, it was confirmed that a standard deviation of 30 nm on theeight measurement can be achieved. The confocal profilometer can be effectivelymployed to the automatic optical inspection (AOI) task of the brightness n h a n c eme n t f i lms ( BE F ) f a b r i c a t e d b y t h e R 2R p r o c e s s e s .
Subjects
chromatic
3D Profile reconstruction
image
Confocal
Type
thesis
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