化學添加劑在次微米溝漕填孔效果的快速檢測法開發

Abstract

本研究開發一種應用在120 nm溝槽之化學添加劑對填孔效果影響的電化學快速檢測法，並藉由研究兩個彼此間化學結構與分子量相近的新平整劑來驗證。此檢測法是以旋轉電極運用高低不同轉速模擬溝渠開口與底部之不同鍍液流速，在定電流狀況下量測輸出電壓值差來推斷鍍液配方之填孔效果。本研究的實驗以不同的平整劑與不同濃度做為操控變因。旋轉電極的檢測結果與掃描式電子顯微鏡所觀測到的填孔效果一致，且發現添加劑的化學結構與濃度對於填孔效果均有顯著的影響。為了進一步解釋平整劑濃度對填孔效果的影響，使用晶圓破片做為電極的定電流量測結果來解釋平整劑的作用機制。原子力顯微鏡的分析與X光繞射分析並無發覺平整劑濃度對於鍍膜表面平整度與晶相的顯著影響。

A rapid evaluation method on chemical additives for Cu filling performance in 120 nm is developed in this study. Two new levelers; 4-amino-2,1,3-benzothiadiazol and 6-aminobenzo-thiazole were employed to validate the usefulness of this method. A faster and a lower rotating speed were used to simulate the convection rates at the trench open and trench bottom, respectively. The potential difference between these two rotating speeds under galvanostatic measurements were used to predict the superfilling abilities. Levelers in various concentrations were explored. The prediction from the RDE analysis was consistent with the results of SEM observations. In addition, it was found that the chemical structure and concentration of leveler exerted considerable influences over the filling performances. To further explain the influence of leveler concentration to the filling behavior, galvanostatic measurements using wafer fragments as working electrode were conducted to investigate the responsible mechanism of leveler. The results of AFM analysis and X-ray diffraction did not reveal any notable influence of leveler concentration on the surface roughness and preferential phase.