含N’N-二乙基硫脲添加剂的微电铸工艺金属铜填洞机理  

Research on copper gap-filling in micro electroplating process with N'N-diethylthiourea

作　　者：张涛[1] 吴一辉[2] 杨建成[1] 张平[2] 刘永顺[2] 

机构地区：[1]天津工业大学机械电子学院,天津300160 [2]中国科学院长春光学精密机械与物理研究所应用光学国家重点实验室,吉林长春130033

出　　处：《光学精密工程》2008年第9期1701-1705,共5页Optics and Precision Engineering

基　　金：国家自然科学基金资助项目(No.60574089);天津工业大学青年基金资助项目(No.029735)

摘　　要：为了研究含N’N-二乙基硫脲添加剂的微电铸工艺金属铜填洞机理,采用线性伏安法、循环电压电流溶出法(CVS)、扫描电镜(SEM)以及XRD测量法研究了N’N-二乙基硫脲对微电铸工艺电化学行为的影响,并借助塔菲尔方程,研究了微电铸铜反应过程中的电极动力学参数。结果表明,当微电铸铜工艺中加入N’N-二乙基硫脲添加剂时,产生活性极化,提高了铜离子还原时所需的活化能,金属离子的放电速度从2.221 4 mA/cm2降低到约0.076 mA/cm2,从而增加了反应时的过电位,促使电极表面晶核成型速度增加,晶体成长速度由2.57μm/min降低到约0.17μm/min,铜离子的平滑能力提高约50%,有效地减小了微电铸时的边沿效应,使金属铜具有良好的填充微型孔洞的能力。本实验通过微电铸工艺成功地将金属铜填充入宽为10μm,深宽比为4∶1的微型凹槽中,且镀层内没有空洞、空隙及细缝等缺陷。In order to investigate the copper gap-filling in micro eleetroplating process with additive （N＇N-diethylthiourea）, the electrochemical behaviors of electrolyte were analysed by SEM, CVS and XRD, and the electrode dynamic parameters were studied by the Tafei equation. The results show that when N＇N-diethylthiourea is used in micro electroplating copper process, an activation polarization is generated to improve the activation energy, the metal ion discharge rate is lowered from 2. 221 4 mA/cm^2 to about 0. 076 mA/cm^2. Therefore, the overpotential is increased, and the crystal nucleus molding speed on the electrode is accelerated; so that the crystal growth speed is decreased from 2.57 μm/min to about 0.17 μm /min,and the leveling ability is increased about 50%. Experiments show that the side effect is lowered effectively, which makes the copper ions get a good filling ability for micro-trenches. Furthermore, some micro trenches in the silicon wafer with the width of 10 μm and aspect ratio of 4 ： 1 are filled by metal copper in micro electroplating process with N ＇ N-dieth-ylthiourea, the electroplating layer have no voids or seams.

关 键 词：微电铸工艺 N’N-二乙基硫脲 活性极化 电化学行为 填洞能力 

分 类 号：TN405[电子电信—微电子学与固体电子学] TG249.9[金属学及工艺—铸造]