以原子層沉積技術所製作之氧化鋁薄膜性質及其對純銅保護性之研究

Abstract

本研究係使用原子層沉積(atomic layer deposition, ALD)技術於純銅表面成長氧化鋁(Al2O3)薄膜，以各種精密儀器有系統地分析該薄膜的特性，同時以不同的實驗來測試該薄膜對純銅的保護能力。實驗結果顯示，利用ALD技術可順利在純銅表面成長Al2O3薄膜，膜厚可由ALD的循環數(cycle)精確地控制。在適當的製程條件下，當薄膜的化學越成份接近藍寶石的化學計量比，而其折射率、硬度、楊氏模數、附著力也越高，這些變化與薄膜內氫氧基(-OH)的含量有關。然而純銅出現少許局部被攻擊的現象，原因在於薄膜內的缺陷。該缺陷的型態屬於局部較鬆散的結構並扮演外界氧或水氣往內擴散的潛在路徑，底材表面上外來的異質顆粒及ALD製程中殘留的-OH*則是形成缺陷的主因。

In this study, atomic layer deposition (ALD) technique has been employed to prepare Al2O3 thin films onto pure copper. The characteristics of the films were systematically investigated using many sophisticated instruments. Additionally, the protection performance of the films was evaluated by different trials. The analysis results show the Al2O3 thin films are well deposited on pure copper The film thicknesses can be precisely controlled by numbers of ALD cycle. The chemical compositions of the films prepared by appropriate ALD condition are close to the stoichiometric composition of sapphire. The refractive index, hardness, Young’s modulus, and adhesion strength of the films are better too. These behaviors are attributed to the feature of containing less -OH groups in the films. However, few tiny and local attacks of the coated coppers are observed, which can be explained by the defects within the films. The features of the defects are locally looser microstructures that play the roles of potential diffusion paths for oxygen or moisture in the environment. The extrinsic heterogeneous particles and residual -OH* during ALD process are the main reasons which induce the defects.