Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/10050
標題: Effect of chromium diffusion barrier in stress behavior of copper thin film
鉻擴散阻礙層對銅薄膜應力行為之影響
作者: 林義傑
Lin, Yi-Chieh
關鍵字: copper;銅;chromium;diffusion;thin fim;stress;relaxation;plastic deformation;鉻;擴散;薄膜;應力;疏散;塑性變形
出版社: 材料工程學研究所
摘要: 
隨著積體電路內連線的線寬持續縮小,鋁合金內連線的效能和可靠度將很快的達到其最大極限。顯然的,銅將成為繼鋁之後的接班人。然而,銅要比鋁硬許多,這使得溫度變化時,矽基材上的銅薄膜將承受相當大的熱應力。
在本篇論文中,探討了鉻層厚度不同時,SiO2/Si基材上的Al/Cu/Cr結構中之銅薄膜應力行為。至於銅薄膜應力變化的研究方式,則是於真空下進行熱循環(室溫至500℃之間)以及持溫退火(150℃、200℃、300℃)的同時,以in-situ雷射掃瞄技術量測曲率。此外,也檢視了經過500℃退火1小時、2小時,以及4小時後的銅薄膜微結構。
從實驗資料顯示,室溫下的銅薄膜應力將隨著鉻層厚度的變薄而有下降的趨勢。另外,根據利用適當的塑性變形方程式進行擬合和模擬的結果,在降溫過程中,低溫潛變顯然是Al/Cu/Cr結構中的銅薄膜之主要應力疏散機制。

As the dimensions of interconnects for integrated circuits continue to shrink, the performance and reliability achievable with aluminum alloy metallization may soon reach practical limits. Copper is an obvious candidate as a successor to aluminum. However copper is much stiffer than aluminum, which leads, for Cu films on Si substrate, to significantly larger thermal stress for a given temperature change.
In this thesis, the stress behaviors of copper thin film in Al/Cu/Cr structure with chromium underlayers with different thickness on SiO2/Si substrate were investigated. The evolution of stresses was studied using in-situ substrate curvature measurements with a scanning laser method. The heat treatments include isochronal(from room temperature to 500℃) and isothermal(150℃, 200℃, 300℃) annealing in a vacuum. The microstructures of copper thin film were also examined for annealing at 500℃ for 1 hour, 2 hours, and 4 hours.
Form the experimental data, the stress of copper thin film at room temperature was smaller with thinner chromium layer. Besides, according to results of fitting and simulation with equations for plastic deformation, low-temperature creep appears to be the dominant stress relaxation mechanism for copper thin film in Al/Cu/Cr structure during the cooling cycle.
URI: http://hdl.handle.net/11455/10050
Appears in Collections:材料科學與工程學系

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