碳氮化矽/電漿聚合高分子多層結構的阻擋水氣性能探討

Abstract

可撓式有機發光二極體是近年來興新的科技，因為其優異的外型和方便攜帶，使其很有可能成為下一代的顯示器和照明工具。然而，塑膠基板無法有效阻擋水氣和氧氣，是其目前無法量產的主要因素。為了達到可以讓可撓式有機發光二極體可應用的目標，使其的壽命達到10,000小時，學術界和工業界都積極地研究薄膜封裝阻隔技術，使薄膜的水氣穿透速率（WVTR）低於1×10-6 g/m2/day. 在此論文中，我們成功地開發在低溫下（≤60℃）使用電漿化學氣相沉積(PECVD)的方式，於聚對苯二甲酸乙酯（PET），沉積碳氮化矽/等離子聚合物多層阻水薄膜結構。吾人使用Bis(dimethyl amino) diethylsilane (BDMADES) 和methyl methacrylate (MMA)作為前驅物，分別當作無機層和有機層。在本研究中為了更進一步降低WVTR，也探索了減少沉積薄膜缺陷的方法。在具體上，我們研究了沉積壓力對SiCxNy膜中的缺陷的影響。此外，為了提供良好沉積環境以減少SiCxNy 層的缺陷，PPMMA層將會被改質以改善其表面特性。 在本研究指出，提升壓力的增加可減少SiCxNy 40％的缺陷密度。此外，在沉積SiCxNy層之前對PPMMA表面做改質可以減少60％減少缺陷密度。總體而言，五對SiCxNy / PPMMA薄膜的WVTR可以降低到7.1×10-5 g/m2/day，還有增加延遲時間到17小時。

In recent years, flexible organic light emitting diode (FOLED) has emerged as the next-generation display and lighting due to their outstanding form factor and mobility. However, the reliability issues resulting from the poor moisture and oxygen barrier performance of plastic substrate is hindering the proliferation of FOLED. This prompts the academia and industry working fervently on thin-film encapsulation barrier technology to meet the goal of 10,000-hr lifetime, whose water vapor transmission rate (WVTR) shall be kept preferably below 1x10-6 g/m2-day for FOLED application. In this thesis, we successfully developed a low WVTR multi-layered structure of silicon carbonitride/plasma polymerized polymer deposited on flexible polyethylene terephthalate (PET) substrate by PECVD at low temperature (≤ 60 oC). Bis(dimethylamino)diethylsilane (BDMADES) and methyl methacrylate (MMA) are selected as the precursors for depositing inorganic and organic layers, respectively, to improve the intrinsic WVTR. This work also explored methods for reducing the pinhole density in the multi-layered barrier to further reduce WVTR. In specific, we examined the effects of deposition temperature and pressure on the defects in SiCxNy films. In addition, PPMMA layer was modified in order to achieve high-quality SiCxNy film with reduced defect in the subsequent deposition. Our study indicates that an increase in pressure can reduced the pinhole density of SiCxNy, 40%. Besides, surface modification of PPMMA prior to SiCxNy deposition leads to 60% reduction of pinhole density. Overall, the WVTR of five-pairs of SiCxNy/PPMMA thin-film barrier can be reduced down to 7.1×10-5 g/m2/day, with a lag-time of 17 hours.