- 學位論文
應用膠片投射疊紋法於微小尺寸元件暨陰影疊紋法於大尺寸元件之面平整度檢測
Micro Size Surface Measurement using Projection MoiréMethod with a Film Grating and Large Size Surface Flatness Measurement with Shadow Moiré Method
摘要
疊紋法(Moiré Method)量測技術用在試體面外(Out of Plane)或是面內(In of Plane)的檢測上面已經是常見的方法。其優點為量測迅速、精度高、儀器架設容易且為全域式的非接觸量測。但是，其廣為應用各領域則需更多研究之投入。本研究針對疊紋法的特點，將量測範圍擴大，深入開發疊紋法於微小尺寸及大尺寸上的量測研究。在探討微小尺寸之翹曲量測時，以IC構裝中常見之錫球銲墊(Solder Ball Pad)為研究樣本。此銲墊在深度方面的規格約在10μm左右，與此規格相差太多將影響銲墊與錫球間的完整接合與訊號傳輸。所以運用疊紋法翹曲量測原理，研究類似此微小銲墊深度等級的量測，將對品質之提升有所貢獻。而在探討大面積量測方面，則以液晶顯示器背光模組上之導光板為例。因導光板(Light Guide Plate)薄型化後，造成成型後之翹曲問題，影響光通過導光板後的均勻度(輝度)，會造成視覺上之瑕疵。此外，研究亦探討光源選取對這些改良式的疊紋法影響。 本研究首先開發檢測微小試體的微小投射疊紋(Projection Moiré)系統，運用自製之光學系統架設於光學顯微鏡前，包含自製之精密膠片光柵置於顯微鏡上，使之縮小作投射光柵用，再加入影像處理技術及相位演算法而檢測出微小銲墊深度。至於大尺寸的陰影疊紋(Shadow Moiré)系統開發，架設相關設備並以相位演算法計算，即可量測出導光板之翹曲量。此外，亦針對進行陰影疊紋檢測時，分別探究應用三種部分同調之光源，比較其對干涉疊紋對比度的影響。 實驗結果顯示銲墊檢測數據與規範做比對，誤差在8%左右，且若產生之疊紋越密，更有助於樣本在邊緣及內部之曲面重建的正確性。而在大面積導光板量測部分，發現以藍光作檢測將可得到較高對比度之干涉疊紋。最後，應用雷射位移計做疊紋量測精準度驗證時，顯示在導光板有數毫米(mm)以上的翹曲量時，兩者相對誤差卻只有1μm~150μm，證實陰影疊紋檢測系統確實有高精度的量測結果。
並列摘要
Moiré method is widely used for both the out-of-plane and in-plane surface measurements. It has advantages of fast, high precision, full-field, non-contact, and easy to set up. However, the extension of its use still needs to be explored with some research efforts. The study will develop the techniques of Moiré method in measuring the micro size and large size surfaces. The typical micro sized solder ball pad of the IC packaging and the large sized light guide plate of LCD backlight module are used as the study examples. For the former, the specification in its depth is around 10μm. This dimension is critical since it will affect the contact between solder ball and pad thus also influences the circuit connecting quality. While for the latter, the problem is due to the thinning of light guide plate currently always causes the surface warpage. This will affect the uniformity of the light which passes through the light guide plate. Other than these, the improvement of the experimental results by using different light sources is also investigated. For the development of micro projection Moiré system, a series of optical devices is set up right in front of the optical microscope. It includes a self-made precision film grating to project onto the optic microscope. This projected grating together with the digital image process technique and phase algorithm can then solve for the surface measurement of the micro sized pad. In the case of using Shadow Moiré for the large size surface measurement, the warpage of the light guide plate is measured after the setting up of related devices and the use of the phase algorithm for the calculation. Besides, the three partial coherent light sources are tested and the contrast among the resulted fringe patterns are compared with for the best performance in the Shadow Moiré measurement. The experimental results show that the data of pad measurement is within 8% difference when comparing with that of the specification. It is also reveals that with denser fringe patterns, the correctness of the reconstructed measured surface will be improved. Also, the higher contrast of fringe pattern on the light guide plate is observed when the blue light is used as the light source. Finally, for checking the precision of the measurement, the laser displacement sensor is adopted for point by point measurement, It is found that the difference only lies between 1μm~150μm when the light guide plate having warpage at some millimeters range. It is concluded that the developed Shadow Moiré systems have high accuracy for the precision measurement purposes.