兩種含硫醇基添加劑對電鍍銅填孔力影響之研究

Abstract

以6-amino-2-mercaptobenzothiazole及 2-mercapto- benzothiazole兩種含硫醇基的有機化合物分別作為微尺寸銅電鍍的添加劑。在具備120nm寬度溝槽的矽晶圓基板上電鍍銅，並觀察添加劑對填孔能力的影響，同時以AFM觀察電鍍銅層的表面平整度。 從I-V量測分析，添加6-amino-2-mercaptobenzothiazole配方有較好的加速銅離子還原能力，但此配方在低添加濃度高電鍍電流與高添加濃度低電鍍電流條件下，無法獲得“superfilling”的填孔效果。其中除了添加100 μM 6-amino-2-mercaptobenzothiazole配方於低電流密度電鍍下的銅導線試片會出現空孔缺陷，其餘配方均可以達成IBM理論中所謂“superfilling”的效果。高添加濃度於高電鍍電流條件下電鍍，因利於均勻成核故試片表面形貌較平整。

Compounds of 6-amino-2-mercaptobenzothiazole and 2-mercaptobenzothiazole were investigated as chemical additives for Cu electrodeposition in trenches of 120 nm width on Si substrates. The Scanning Electron Microscope was employed to observe the morphologies of the electrodeposited Cu and evaluated the trench-filling abilities of the additives. Electrochemical analysis was conducted to measure their respective reducing performances and Atomic Force Microscope was adopted to record the surface roughness. From current-potential profiles, the additive of 6-amino-2-mercapto- benzothiazole exhibited an enhanced Cu electrodeposition behavior. Unfortunately, it was not able to deliver the “superfilling” requirement at low concentration/high depositing current, as well as high concentration/low depositing current. For both additives, improved surface characteristics were obtained at high concentration and current density