印刷技術製備導電金屬線和圖案化薄膜與元件之應用

Abstract

噴墨印刷可透過電腦輔助，將墨水準確地噴印於特定的位置上，製作出各式特殊元件，因此具有節省原料使成本降低、非接觸式、高精準度與不需開模等特性，此技術對於基板的要求也較為寬鬆，因此適用於可撓曲基材上製作元件，有效提升軟性電子產業的發展潛力。本論文為了探討噴墨印刷技術在可撓曲基材上的可行性，將各種奈米粒子墨水與化學反應墨水來噴印沉積於基材上，主要探討分為四大部分，包括製備出各種穩定的特殊性墨水，低溫下生產出導電薄膜材料，並且可快速噴印製成薄膜圖案，最後進行電子元件的開發與應用。 首章節吾人將概述噴墨印刷的應用與發展歷史，並且對此技術的原理和文獻做探討。而為了有效提升噴墨印刷的品質，墨水的穩定是非常重要的，在第二章中，將使用物理或是化學合成的方法製備奈米粒子與高分子墨水，除了探討各種墨水的穩定性與墨水的特性分析，且進行噴塗測試，找出墨水噴印沉積於基板表面之間的最適化。 為了降低噴印後，後處理的燒結溫度過高會直接影響噴塗印製時所需的基板限制的問題，在第三章，將使用雙噴頭的噴墨反應系統，把兩種墨水(銀離子墨水與PVP/甲醛墨水)利用噴墨技術同時噴印於基板上，進行化學反應，形成銀導線薄膜，在室溫下即可形成導電銀線，導電度最佳約為純銀導電度的10%，燒結100℃一小時候可提升至純銀導電度的23%，可有效降低燒結溫度，減少基板限制。 此外，為了減少在無電鍍下製作銅薄膜繁瑣的製程，在第四章利用簡單而快速的方法，在各種軟性塑膠基板上製造出不同圖案的導電銅薄膜。利用噴墨技術噴塗銀離子墨水於基材上，再把噴塗好的樣品放入無電鍍銅溶液，即可在低溫下形成高導電銅薄膜，乾燥後約為純銅導電度的83%，並且具有良好的可撓曲性與附著性。 最後在第五章則整合了PEDOT:PSS墨水、奈米二氧化鈦墨水與奈米銀墨水，利用工業用印表機製作出微電子元件，包含觸覺單元元件與電阻式記憶體元件，並進行特性量測和檢視印製元件之功能，測量結果顯示印製出的元件具有優良之機電特性，顯見噴墨印刷技術可有效製作各種電子元件，並可大量應用於軟性電子產業。

With computer assistance, inkjet printing can accurately print ink onto specific locations and produces various unique components. Therefore, inkjet printing technology possesses the characteristics of material savings and cost reduction, and does not require contact or mold opening. Furthermore, inkjet printing technology can be applied to flexible substrates and potentially can be employed in the electronics industry. In this study, an inkjet printing technique was used to deposit various nanoparticle or chemical reactive inks onto plastic substrates. This study comprises of four major aspects: preparing various functional inks, producing conductive thin films under low temperatures, rapidly printing thin film patterns, manufacturing electronic components. The history and applications of inkjet printing technology will be generally introduced in Chapter 1, and the principal theories and relative literatures will be discussed as well. Chapter 2 introduces physical or chemical synthetic methods for the preparation of stable nanoparticle and polymer inks. Printing tests and material characteristic analysis were conducted to further optimize nanoparticle deposition on substrate surfaces. In Chapter 3, a new method is described for conductive silver film formation. An inkjet printing device with two ink channels was used to deposit silver thin films. Two inks, silver ammonia and PVP/formaldehyde solutions, were separately ejected, mixed, and reacted on the substrates. The electrical conductivity of the resulting silver lines is 10% of bulk silver at room temperature. After sintered at 100 °C for an hour, electrical conductivity can be enhanced to 23%. In addition, a simple and efficient method is developed to create conductive copper thin films on polymer surfaces in Chapter 4. Micropatterns of silver nitrate inks, which serve as an activating agent for copper plating, were printed and dried on flexible plastic substrates. The printed plastic sheets were then immersed in an electroless copper plating bath to create copper thin films on the printed patterns. The prepared copper films have an electrical conductivity as high as 83% of bulk copper and show good adhesion on flexible substrates. In Chapter 5, we used the PEDOT:PSS ink, TiO2 ink and silver nanoparticle ink to fabricate microelectric devices, such as taxel device and RRAM device. The devices were created and showed excellent performance. Those results indicate the feasibility and great potential of applying inkjet printing technology on flexible electronic devices.