本論文旨在藉由物性及電性量測，就應用於銅金屬製程銅擴散阻擋層金屬–碳化鈮（NbC）進行熱穩定度分析。於實驗所使用之物性分析方法包括有XRD、 XPS、 SEM、 AES、 SIMS等，而於電性方面，則包括有片電阻和P+N接面二極體之反向漏電流之量測分析。
利用直流濺鍍設備及NbC(50-50 at%)靶，於通入氮氣且壓力保持在7.6×10-3 torr的真空條件下，沉積所得碳化鈮阻擋層其電阻係數約為1774μΩ-cm。針對Cu(200nm)/NbC/p+n-Si結構，當NbC阻擋層厚度分別為60nm、 30nm、 以及15nm三種厚度時，於N2環境熱處理30分鐘後，經由二極體漏電流的量測結果顯示，其熱穩定度或失效溫度(Failure temperature)分別為450°C、 400°C、及350°C。藉由SIMS進行試片之元素成分縱深分析得知，NbC阻擋層之故障機制主要係銅原子經阻擋層中晶界之擴散所構成，此一情形對較薄的阻擋層厚度(15nm)甚為明顯。再藉由AES縱深分析顯示，隨著熱處理溫度之提高，NbC阻擋層與銅金屬層間原子相互擴散行為隨之加劇，最後並導致兩層間之反轉現象(Layer Reversal)。配合XRD、SEM、及片電阻等分析，吾人發現在相同熱處理情況下，具有較厚NbC阻擋層(60nm)之試片其反轉現象遠較厚度較薄試片(15nm)者明顯。
為進一步提昇NbC層之失效溫度，我們嘗試於NbC沉積過程中進行氮摻雜。實驗結果顯示，在N2/Ar流量比(流量單位為sccm)分別為0.5/24及1/24所得之NbCN阻擋層，於60nm的厚度下，雖然阻擋層之電阻係數稍顯增加(約在2000～2700μΩ-cm之間)，但其熱穩定溫度可提高至500°C。同時藉由XRD及SIMS進行成分縱深分析證實，適當之氮摻雜可使原NbC層晶界獲得填塞，銅擴散及層反轉現象均可有效改善。

In this thesis, electrical and physical analyses were used to investigate the performance of niobium carbide (NbC) as a diffusion barrier in Cu metallization. In our study, physical analysis including XRD, XPS, SEM, AES, and SIMS depth profile were employed. Electrical analyses based on sheet resistance analysis and leakage current measurement of p+n diodes were also utilized. The resistivity of NbC thin films deposited by a DC sputtering system was about 1774μΩ-cm. Both Cu(200nm)/NbC/Si and Cu(200nm)/NbC/p+n-Si were prepared and these samples were subjected to thermal annealing under N2 ambient for 30 min. According to leakage current measurement of the Cu(200nm)/NbC/p+n-Si diodes, the failure temperature of the 60nm-, 30nm-, and 15nm-thick NbC barrier layer sample was found to be of around 450°C, 400°C, and 350°C, respectively.
According to SIMS depth profile, the failure of the annealed samples was found being attributed to Cu diffusion through the grain boundaries inside the NbC layer. It is noted that, after thermal annealing at a temperature higher than the failure temperature, layer inversion between the top Cu layer and underneath NbC barrier layer occurred. As also verified by XRD and SEM, the layer inversion phenomenon is seen being much more apparent for the sample with thinner NbC layer.
To further improve the thermal performance of the NbC barrier layer, nitrogen doping was employed during NbC preparation. Our experiment reveals that, with an N2/Ar flow rate (both in sccm) ratio of 0.5/24 or 1/24, though the film resistivity was increased to be of around 2000μΩ-cm to 2700μΩ-cm, layer inversion phenomenon has been released, and was evident in XRD analysis. In addition, the failure temperature of the 60nm-thick sample has been increased to be of 500°C. As indicated by SIMS analysis, it is attributed to the fact that the incorporated nitrogen atoms will reside at the grain boundaries of the NbC layer, as a result, Cu diffusion has been effectively suppressed.

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