新型整平剂对电镀铜填通孔的影响及机制探究

Influence and mechanism of new leveler on through hole filling by copper electroplating

针对目前国内电子电镀专用化学品瓶颈问题,合成了一种由含氮杂环与含氧碳链组成的新型整平剂分子SC-21。通过哈林槽实验、循环伏安法(CV)、计时电位法(CP&CPCR)和电化学交流阻抗谱(EIS)对比,研究了常见整平剂健那绿(JGB)、聚乙烯亚胺烷基盐(PN)与新型整平剂SC-21在电镀铜填充通孔过程中的作用差异。结果表明:以一定浓度SC-21为整平剂时可出现“蝴蝶填充”现象,进而实现对深径比2∶1通孔的无空洞填充;与JGB和PN相比,此浓度下的SC-21在较宽的电流密度范围内具有动态吸附行为,可产生“负微分电阻效应”,使得通孔内呈现与“蝴蝶填充”形状相匹配的沉铜速率梯度,最终实现对通孔的无空洞填充。

To solve the bottlenecks of the specialized chemicals for electronic electroplating in domestic,a new leveler named SC-21 was synthesized.It was consisted of a nitrogen-containing heterocycle and an oxygen-containing carbon chain.In this paper,the different performances between the common leveler of Janus Green B(JGB),polyethyleneimine alkyl salt(PN) and the new leveler SC-21 were studied by copper plating in haring cell,cyclic voltammetry(CV),chronopotentiometry(CP & CPCR),and electrochemical impedance spectroscopy(EIS).The results indicate that the copper deposition mode of “butterfly filling” can be achieved using a certain concentration of SC-21 as the leveler.Finally,the through holes with the depth to ratio of 2∶1 can be completely filled without void.Compared with JGB and PN,SC-21 at this concentration showed a dynamic adsorption behavior in a wide range of current density,which resulted in the appearance of "negative differential resistance effect"(NDR effect).The NDR effect can lead to the velocity gradients of copper deposition in the through hole,which finally resulted in the void-free filling of through holes.