電化學原子層沉積製備銅銀合金薄膜於連導線應用之特性探討

Preparation and Characterisitics of Electrochemical Atomic Layer Deposited Copper-Silver Alloy Film on Interconnection

柳耀翔(Yiou-Hsin Liou)

指導教授 ： 方昭訓

國立虎尾科技大學/工程學院/材料科學與綠色能源工程研究所/碩士(2014年)

https://doi.org/10.6827/NFU.2014.00266

摘要

本研究以電化學原子層沉積(EC-ALD)製備Cu-Ag 合金薄膜，電化學原子層沉積結合原子層沉積及低電位沉積。銀金屬材料可解決連導線越來越窄化的低電阻需求且電流密度可達4.13 mA/cm2　，結合ECLAD技術填充溝渠有極佳的潛力。
以磁控濺鍍在Si(100)上沉積10 nm釕薄膜並利用循環伏安法(CV)在10 mM溶液中使用5 mV/s 掃瞄速度去除氧化層製備基板。使用低電位沉積在釕基板上以0.1 V先沉積一層銅原子層，選擇鉛作為犧牲層在銅原子層上以-0.5 V UPD沉積一層鉛原子層，接著在開路電壓(OCP)下通入含銅離子溶液將鉛原子置換成銅原子得第二層銅原子層並以UPD在-0.05 V沉積一層銀原子層於銅薄膜。銅銀合金薄膜利用上述步驟：每五層銅原子層沉積一層銀原子層，重複五十次可得。結果以X光繞射分析儀(XRD)、四點探針(FPP)和X射線光電子能譜學（X-ray pHotoelectron spectroscopy）分析薄膜特性。
研究指出每個循環可沉積0.51 ML銅，且銅薄膜與銅銀合金薄膜最低電阻率分別為3.6 與 2.2 μΩ．Cm，XRD繞射光譜以銅(100)、(200)繞射峰為主，並向小角度偏移證銀原子進入銅晶格中。

關鍵字

電化學原子層沉積 ； 低電位沉積 ； 氧化還原置換反應 ； 連導線

並列摘要

This paper describes the formation of Cu and Cu-Ag nanofilms using electrochemical atomic layer deposition (EC - ALD), which combine atomic layer deposition (ALD) with underpotential deposition (UPD). Ag materials and technigues may ultimately be need to address the low resistivity requirements of interconnection, which are project to have current density greater than 4.13 mA/cm2 by 2018, and super-filling Cu-Ag using the great gap filling of EC-ALD.
The Si (100) wafer coated with 10 nm Ru films by pHysical vapor deposition, and the substrate was cleaned by cyclic voltammetry in 10 mM HCLO4 at a scan rate of 5 mV/s to remove the oxide layer. Cu underpotential deposition was used to deposit the first Cu atomic layer on Ru substrate. Pb was chosen as the sacrificial layer as it forms atomic layers on Cu via underpotential deposition and then Cu2+ solution was flushed into the cell at open-circuit potential where the Pb atoms were exchanged for Cu by redox replacements. The Cu bulk layer formation was by repeating the above step several times and then deposited Ag atomic layer on Cu using underpotantial deposition. Cu-Ag samples were formed using the sequence by performing 50 periods, each consisting of 4 cycles Cu and 1cycle Ag. The deposition were grown using 0.1 and -0.05 V for Cu and Ag precursor solution.The resulting Cu-Ag films were characterized using X-ray diffraction (XRD), electrochemical chromatograpHy and four point probe (FPP).
The result indicates the average formed amount of Cu per replacement cycle was 0.51 ML, that the lowest resistivity 3.6 and 2.2 μΩ．cm for Cu thin film and Cu-Ag thin film. The XRD pattern for 500 cycles displays two left-shifted peak, (111) and (200) for Cu, its show that the Ag atom moved into Cu lattice. As results of the self-limiting reactions and electrochemical suface limited reaction, EC-ALD have the great ability-deposited of atomic-level control, fabricated nano-scale filling processes.

並列關鍵字

electrochemical atomic layer deposition (EC-ALD) ； underpotential (UPD) ； redox replacement ； interconnection

參考文獻

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