有機矽酸鹽層/含氟聚亞醯胺奈米複合材料於先進介電材料之應用

Abstract

本論文使用兩種矽酸鹽層(montmorillonite及Mica)和兩種改質劑(2NH2及3NH2)與含氟聚亞醯胺(6FDA-ODA)製備出2NH2-mont/6FDA-ODA及3NH2-Mica/6FDA-ODA兩種複合材料，這兩種複合材料在經X光分析及電子顯微鏡分析後，確定形成夾入型奈米複合材料。在熱性質方面，添加5wt％之2NH2-mont與3NH2- Mica分別使6FDA-ODA之耐裂解溫度較純的時(522℃)提高11及10℃；而250℃時之熱膨脹係數亦分別較純的下降33％及34％。動態機械性質方面，添加5wt％之2NH2-mont使6FDA-ODA之儲存模數及損耗模數分別提升83％及63％；而添加3NH2-Mica則分別提升89％及75％。而各狀態時分子鏈段運動所需之活化能明顯因層狀矽酸鹽的保護而提高，其中以3NH2-Mica之ΔHβ及ΔHα分別為58.9 及565.7 kcal/mol-K提高最多。在張力機械強度方面，以含量5wt％為例，在2NH2-mont系統中，楊氏模數及最大拉伸應力分別增加為2.55 GPa和96.6 MPa；而3NH2- Mica系統則分別增加為2.74 GPa和97.8 MPa。在表面壓痕硬度方面，添加5wt％之2NH2-mont後，表面硬度值為純的6FDA-ODA的兩倍(0.17 vs. 0.34 GPa)。吸濕性方面，皆以含量3wt％時的改善效果最佳，其中2NH2-mont之飽和吸濕量較純的降低了55％；而添加3NH2-Mica降低57％。 電氣性質方面，3NH2-Mica能有效的抑制水氣對薄膜電氣性質的破壞，在受水氣滲透處理20小時後，純的6FDA-ODA薄膜之漏電流密度增為原來的29倍(3.5 vs. 102.1 pA/mm2)，介電係數從2.68增至3.53；而含量3wt％之奈米複合薄膜之漏電流密度僅增為原來的6倍(4.1 vs. 22.9 pA/mm2)，介電係數從2.83增至3.20。在銅擴散阻障性方面，從SIMS和TEM分析結果證明矽酸鹽層具有阻障銅擴散之效果，在靠近界面處，銅在3NH2-Mica/6FDA-ODA中的擴散係數為在純的6FDA-ODA薄膜中的28％。在接著性方面，3NH2-Mica可以提升6FDA-ODA薄膜與銅膜的接著強度，含量5wt％時，其接著強度較純的增加157％(437 vs. 170 N/m)。

In this study, two nanocomposites of 2NH2-mont/6FDA-ODA and 3NH2-Mica/6FDA-ODA formed through two multiple functional groups swelling agents and two different size layered silicates were analyzed. The X-ray and TEM results provide a direct evidence of this nano-meter scale dispersion of intercalated silicate layers in 6FDA-ODA. In thermal properties, for 5wt% 2NH2-mont and 3NH2-Mica in 6FDA-ODA, the decomposition temperature (at 1% weight loss) increased 11 and 10℃ respectively as compared to that of pure 6FDA-ODA. The coefficients of thermal expansion were 33% and 34% lower than that of pure 6FDA-ODA, respectively. The storage moduli and loss moduli for 5wt% 2NH2-mont in 6FDA-ODA increase 83% and 63% respectively as compared to that of pure polyimide. For 3NH2-Mica system, these were 89% and 75% larger than that of pure PI, respectively. The activation energy of layered silicates/6FDA-ODA nanocomposites increased substantially over that of pure polyimide, owning to the better bonding and the restriction of larger layered silicates on the movement of polyimide molecules. The maximum increases in the ΔHβ and ΔHα of 3NH2-Mica/6FDA-ODA were 117% and 135% respectively as compared to that of pure PI. The Young’s modulus and maximum stress of 2NH2-mont/6FDA-ODA nanocomposites increased 69% and 37% respectively as compared to that of pure 6FDA-ODA. In the case of 3NH2-Mica/6FDA-ODA, the Young’s modulus and maximum stress were 73% and 32% higher than that of pure PI, respectively. Additionally, for 5wt% 2NH2-mont in 6FDA-ODA, the surface hardness was 100% larger than that of pure polyimide. In the case of 6FDA-ODA films containing 3wt% 2NH2-mont and 3NH2-Mica, the saturated amount of absorbed water were 55% and 57% lower than that of pure polyimide. In electric properties, the leakage-current density of 6FDA-ODA after being treated under ambient conditions for 20 hours is about 29 times that of pristine polyimide, but for 6FDA-ODA containing 3wt% 3NH2-Mica, there is only a 6-fold increase. The dielectric constants of pure 6FDA-ODA and 3wt % 3NH2-silicates in 6FDA-ODA are 3.53 and 3.20, respectively, after treating under ambient conditions for 20 hours. In addition, the diffusion of Cu across the interface of Cu/(3NH2-Mica/6FDA-ODA) is investigated with SIMS and TEM. For 3wt% 3NH2-Mica in 6FDA-ODA, the diffusion coefficient of Cu near the interface of the nanocomposite is less than one third that of the pure polyimide. The adhesion strength of 6FDA-ODA having 5wt% 3NH2-Mica was 157% higher than that of pure 6FDA-ODA (437 vs. 170 N/m).