自我鈍化型銅鋁合金薄膜之抗氧化性及電性研究

本研究主要探討Cu(Al)合金薄膜之自我鈍化特性由於Cu元素較Al元素有較低的電阻率與較高的抗電子遷移的特性因純銅無法自我鈍化且與玻璃基板的附著性差，所以在製程中Cu導線的應用卻被受限制。因此本研究製備低電阻率、具有自我鈍化Cu(Al)合金薄膜，期望能取代傳統鋁金屬導線應用於TFT-LCD與半導體製程之元件。本實驗利用磁控共濺鍍法(Magnetron Co-sputtering)在康寧Eagle2000玻璃基板上製備Cu1-xAlx (x =1.75-7.5 at.% )合金薄膜，藉由改變靶材濺鍍功率以獲得不同Al含量的合金薄膜。薄膜成分以EDS分析，並利用快速退火爐(Rapid Thermal Annealer )對薄膜進行200 - 600˚C持溫10-30分鐘熱處理，最後以XRD、FPP(Four point probe)、SEM、Scotch Tape Test等分析，探討Cu(Al)合金薄膜經熱處理前後之結構及電性變化。結果顯示，在氧氣環境下熱處理Al會擴散至薄膜表面形成Al2O3/Cu/SiO2之自我鈍化薄膜，結構分析顯現除了Cu結晶相外並無其他介金屬化合物生成。且薄膜電阻率亦隨著Al含量比例減少而有降低的趨勢，當Al含量為1.75at.% 之合金薄膜經600˚C 30分鐘熱處理後可達到3.04 μΩcm之最佳電阻率。

關鍵字

磁控濺鍍；低電阻率；自我鈍化；銅鋁合金薄膜；附著性

並列摘要

In this study, the characteristics of Cu(Al) alloy thin films and its applications as the materials of interconnect were investigation. Copper has much lower electrical resistivity and higher electron migration (EM) resistance than that of aluminum. The copper suffers from poor adhesion with glass substrated and self-passivation layer after anneal. This work aims at preparing a low resistivity, high adhesion, oxidation resistance and self-passivated Cu(Al) alloy thin film, which will be potentially as gate material on TFT-LCD and interconnection on microelectronics. Cu1-xAlx (x = 1.75-7.50 at.%) films were prepared by a co-sputtering method and were subsequently annealed by a RTA in a temperature range of 200°C - 600°C for 10-30 min in oxygen ambient. Self-passivated Cu thin film in the form of Al2O3/Cu/SiO2 was therefore obtained because Al diffused easily from matrix to the surface and reacted with oxygen by forming, thus oxidation of copper film can be prevented. The formation of Al2O3/Cu/SiO2 improved the resistivity, adhesion to SiO2, oxidation resistance and passivative behavior of the studied film. The Cu (1.75 at.% Al) thin film had the lowest resistivity of 3.04 μΩcm, and exhibited a superior passivated behavior among the studied films.

並列關鍵字

Thin-film transistor ； Cu(Al) alloy thin film ； self-passivation ； adhesion ； low resistivity ； co-sputtering

參考文獻

[1] 楊正杰、張鼎張、鄭晃忠，銅金屬與低介電常數材料與製程，微毫米通訊期刊，第七卷第四期43頁

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