含氧摻雜SiC介電阻障層與Cu製程整合之研究

Abstract

本論文研究介電阻障層於多層導體連線製程上的應用。為了降低訊號傳遞的時間延遲，現今已經發展以金屬銅（電阻率為1.7μΩ-cm）來取代金屬鋁（電阻率為2.7μΩ-cm）成為導線的連線系統。而在降低電容方面，則朝向低介電常數 ( low-k ) 材料發展。但是在銅鑲嵌的製程與電性操作的環境下，溫度與電場的作用，銅極易擴散至低介電常數材料中，並與之發生反應，造成材料特性的劣化與漏電流增大，甚至導致介電質崩潰。因此，在符合製程相容性要求的前提之下，發展具抗銅金屬擴散特性的介電阻障層材料，便成為重要的研究課題。 目前一種含氧碳化矽(silicon carbide)材料薄膜，具有低的介電係數(k~3.7)，因此受到廣大的矚目，而被應用於介電阻障層技術中﹐用來取代傳統具高介電係數的氮化矽(silicon nitride) (k~8)，以降低導線系統的延遲時間。本論文將討論含氧碳化矽膜的基本物性及電性，以及經過研究探討發現其製程整合時遇到氧電漿處理後，打當氧電漿的時間越長，介電常數有增加的趨勢且其漏電特性越好，但是抗銅能力變差。

We know that the metal linewidth and spacing decreases with the device scaling, resulting in large RC time delay. Copper is an applicable alternative due to its low resistivity (1.7 □□-cm), which is much lower than that of Al (2.7 □□-cm). Besides, copper is more resistant to electromigration problem, which is a vital issue in device reliability. The diffusion barrier layer is also served as the etch stop layer during trench formation if necessary. Silicon nitride (SixNy) is the currently standard barrier layer material since it has been employed as a masking and passivating layer for a long time against diffusion of metal ions and moisture. Unfortunately, the relative high dielectric constant (~7) of SixN4yconflicts with the requirement of low dielectric IMD. Recently, a newly-developed dielectric barrier material, amorphous SiOC:H has aroused much attention In this thesis, we observe that after O2 plasma treatment, the leakage current is decreased for both Al and Cu electrode and the resistance against Cu penetration of SiOC:H film is deteriorated after O2 plasma treatment