臺灣博碩士論文加值系統

狹縫式塗佈是應用於積體電路、印刷電路板、液晶顯示器等產業上具有發展潛力的塗佈技術。本研究使用計算流體力學軟體對不同塗刀嘴配置之狹縫式塗佈數值研究進行探討。二維模型主要是與實驗結果之塗佈視窗進行驗證比較。結果發現在較低的平板移動速度和較低的幫浦流量，成膜現象和實驗結果大致相同。然而在較高的速度和流量，模擬成膜的上限值卻遠大於實驗的結果。推測可能是二維模型並無法完全展現出在三維模型會出現的成膜缺陷。三維模型可以通過改變塗佈間隙來預測塗層的均勻性。在此塗刀與平板之間的距離分別為0.25 mm, 0.3 mm及0.35 mm。結果發
現距離0.25 mm的膜最薄，均勻度則是0.3 mm最好。對於不同的塗刀嘴配置，分別考慮上游0.5mm或0.25mm以及下游0.5mm或0.25mm的塗刀嘴。結果發現在流量為1.904g/s，基板速度為0.1 m/s時，前長後短的塗刀塗出來的膜厚為12.2 μm，前短後長為13.2μm，兩者在膜厚上並沒有太大的差異。然而與較短的上游塗刀嘴相比，較長的上游塗刀嘴顯示出更快的塗佈過程。似乎大氣壓力在塗佈過程中扮演著重要的作用。

Slot-die coating is a technology with potential for the development in integrated circuits, printed circuit boards, and liquid crystal displays. In the present study, we use a commercial computational fluid dynamics software to investigate slot-die coating for different die lip configurations. In the two-dimensional model, the result of coating window is compared with published experimental data. The coating window shows a good agreement at the region of low speeds and low mass flow rates. However, a large discrepancy occurs at the upper limit of the plate moving velocity and the pumping mass flow rate. The reason could be that a two-dimensional model fails to predict a realistic boundary condition in the spanwise direction. A three-dimensional model can predict the uniformity of slot-die coating by changing the coating gaps. The coating gaps are 0.25 mm, 0.3 mm, and 0.35 mm, respectively. Results show that the gap of 0.25 mm has the thinnest thickness, and the gap of 0.3 mm has the best uniformity. For different die lip configurations, the die lips with 0.5 mm or 0.25 mm upstream as well as 0.5 mm or 0.25 mm downstream are considered, respectively. At the pumping mass flow rate of 1.904 g/s and the substrate moving velocity of 0.1 m/s, the configuration of the die lip with 0.5 mm upstream and 0.25 mm downstream has the film thickness of 12.2 μm. When the die lips are 0.25 mm upstream and 0.5 mm downstream, the film thickness is almost the same around 13.2 μm. However, the longer upstream die lip shows faster coating process compared to the shorter upstream die lip. It seems like atmospheric pressure plays an important role in the coating process.

CONTENTS

Chinese Abstract . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . i
Abstract . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii
Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . v
Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vi
Nomenclatures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . viii
List of Figures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . x

1 INTRODUCTION 1

1.1 Motivation and objectives . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.2 Background on multiphase flow . . . . . . . . . . . . . . . . . . . . . . . . 2
1.3 Literature review . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

2 MATHEMATICAL FORMULAE AND NUMERICAL METHOD 7

2.1 Governing equations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.2 Numerical model and boundary conditions . . . . . . . . . . . . . . . . . . 9
2.3 Grid independence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

3 RESULTS AND DISCUSSION 12

3.1 Coating window validation . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
3.2 Coating gap analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
3.3 Slot die lip analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

4 CONCLUSIONS AND FUTURE WORK 16

4.1 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
4.2 Future work . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

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