雷射直寫影像技術於氧化銦錫薄膜之電極結構拼接製程研究

Abstract

本研究使用UV雷射加工系統對約40 nm厚之氧化銦錫(Indium Tin Oxide, ITO)薄膜進行電極圖案化，並將完成之電極結構進行拼接，探討雷射直寫影像技術應用於透明導電薄膜大面積電極圖案的製程技術。 實驗中使用波長355 nm的UV雷射於ITO薄膜上進行直寫，藉由調整雷射能量強度、雷射聚焦光斑尺寸、掃描速度及脈衝重複頻率等參數來分析薄膜絕緣線上的刻畫痕跡、電阻值和加工品質，並利用田口方法從實驗數據推算出最佳加工能量和光斑重疊率，確認雷射刻劃出的電極圖案其深度不會破壞至底層基板，劃線深度不會過淺而影響絕緣電阻值。另外，也利用雷射脈衝重複頻率和XY軸振鏡進給速度調整雷射光斑重疊率，探討雷射直寫ITO薄膜之電極圖案效果。 確認最佳化實驗參數後，以XY振鏡掃描範圍內於ITO/玻璃基板直寫電極圖案，搭配雷射加工機台中XY軸步進馬達和導軌組成之平台進行拼接，紀錄圖形偏移位置和誤差量，計算平台移動馬達之回饋修正，進行位置誤差調整補償，讓雷射直寫技術能夠直接完成大面積電極絕緣線圖案。 經過田口法的最佳化實驗後，絕緣線加工深度的最佳化參數包括雷射脈衝頻率50 kHz，振鏡掃描進給速度800 mm/s，雷射功率為2 W。依此最佳化條件再經雷射實驗後，ITO薄膜剝蝕深度約為0.123 μm，光斑直徑為40.54 μm，此加工參數能讓ITO薄膜完整剝蝕，並讓蝕刻出的絕緣線獲得有良好的電阻值。本實驗搭配高速進給拼接技術於ITO薄膜直寫製程，快速完成邊緣平滑和筆直之絕緣線大面積電極圖案。

This study reported the successful development of patterning on indium tin oxide films by using the ultraviolet (UV) laser processing system for stitching the electrode structures. The proposed laser direct imaging of large-area indium tin oxide films was used for projected capacitive touch screens. The UV laser with a wavelength of 355 nm was used in the direct writing on indium tin oxide films deposited on glass substrates. The experiment parameters including laser powers, laser spot sizes, scan speeds of galvanometers, and pulse repetition rates were used to ablate ITO films and to investigate machined quality, such as the electrical resistance and the surface morphology. To calculate the best amount of laser energy and the suitable laser spot overlap from the results of experiment by Taguchi method, the ablated lines could be obtain the better depth and diameter along the processing path without damaging glass substrates. In addition, the laser pulse repetition rate and the scan speed of galvanometers were used to adjust the overlap of laser spot for achieving the perfect electrode structures. After the Taguchi experiment, the optimal parameters included the laser pulse repetition rate of 50 kHz, the scan speed of galvanometers of 800 mm/s, and the laser power of 2 W. Large-area electrode structures were formed by using laser stitching technologies combined with the error compensation technique of an XY-axis feeding stage. The experimental results showed that the ablated depth and diameter of ITO films were 0.123 μm and 40.54 μm, respectively. The ITO film could be fully removed along the ablating path. Furthermore, the ablated lines of large-area electrode structures had smooth and straight edges.