- 學位論文
多波長共焦顯微鏡之探頭研製
New chromatic confocal microscope for full-field micro surface measurement
摘要
本研究利用共焦顯微鏡量測方式(Confocal microscopy)作為理論基礎，並配 合彩色共焦微術(Chromatic confocal microscopy)演算理論與雜訊消除技術，進行 物體三維輪廓重建(3D profile reconstruction)；使用三原色混成之白光光源，經過 光學系統後產生軸向色差，針對單一像素找出其對應的深度反應曲線(Depth response curve)，經由兩色之深度反應曲線進行比值對應深度之線性關係，最後 取得單張景深(Depth of focus)範圍內之影像，利用雷射干涉儀作為Z 軸校正源， 即可對影像上每一像素做比值對深度的運算，進而重建待測物表面輪廓 本研究開發出一套多波長共焦顯微探頭(chromatic confocal microscopic probe)之技術，提供對微奈米三維結構進行量測。此多波長共焦探頭將由探頭光 機模組及訊號處理模組兩部份構成，探頭光機模組由LED 光源及光纖模組、準 直透鏡、分光鏡、繞射光學元件、顯微物鏡、濾光針孔、及三色CCD 等元件所 組成；訊號處理模組含輸入光強之自動功率控制電路及正規化訊號之處理電路。 三色CCD 可提供全域式各量測像素之RGB 波段聚焦訊號，各量測像素之輪廓 高度可由不同波長之聚焦訊號計算獲得，待測件之輪廓量測無需任何垂直掃描動 作，物件可將置於一線性移動台上進行平移式之面掃描，尺寸計算及視覺影像由 PC 負責顯示。針對一微米以上的階高形及三角形微結構可達到解析度為: 縱向 0.5μm、橫向1μm，量測準確度為: 縱向0.2μm、橫向0.2μm。
並列摘要
A chromatic confocal microscopic profilometer for full-field three-dimensional micro surface measurement was developed using innovative multi-wavelength light correlation. Micro/nano structures patterned on the substrate and fabricated by the R2R (Roll-to-Roll) nanoimprint processes are usually having a smooth and low-reflective surface which is not easily measured by the existing optical or contacted methods. It was an extremely difficult task to achieve an effective 3-D profile reconstruction on this kind of micro component by using a traditional confocal microscope. In this paper, a multi-wavelength confocal measurement method employing the focusing cross correlation between three LED color (Red, Green and Blue) lights was introduced to measure micro structures. A compact chromatic confocal microscopic probe was developed by integrating a white light source obtained by mixing the LED light sources and a coaxial confocal optical configuration with a 3-chip CCD camera for individual light sensing. A curve-fitting function between the profile depth and the multi-color focusing correlation was established by a system calibration with a reference to an accurate laser interferometer. To attest the measurement performance, a calibrated reference target having micro-triangular structures was fabricated and measured by the developed methodology. From analysis of the measurement results, it was confirmed that a standard deviation of 30 nm on the height measurement can be achieved. The confocal profilometer can be effectively employed to the automatic optical inspection (AOI) task of the brightness e 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 .