Xu Wei, Li Yedi, Wu Tingjun, Duan Yu, Zhu Lei, Liu Qiang, Wang Yiying, Yu Wenjie
School of Materials and Chemistry, University of Shanghai for Science and Technology, Shanghai 200093, China.
National Key Laboratory of Materials for Integrated Circuits, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China.
Materials (Basel). 2025 Apr 10;18(8):1747. doi: 10.3390/ma18081747.
Copper interconnect technology faces limitations due to the electron's mean free path and electromigration, driving the adoption of cobalt alternatives. This study proposes a novel mechanism to achieve superfilling by tuning the adsorption energy of additive molecules on cobalt surfaces. The adsorption energies of additives are tailored by changing molecular structures with different functional groups. Computational results reveal that carbon-carbon triple bonds critically strengthen adsorption, while ether bonds further enhance binding on distinct cobalt crystallographic planes. Specifically, 1,4-bis(2-hydroxyethoxy)-2-butyne (BEO) containing both triple bonds and ether groups exhibits the highest adsorption energy (-22.62 eV). Replacing ether with hydroxyl groups in 2-butyne-1,4-diol (BOZ) reduces the adsorption energy to -10.39 eV, while eliminating triple bonds in 1,4-butanediol diglycidyl ether (BDE) further decreases it to -8.43 eV. Experimental studies demonstrate that BOZ and BEO preferentially adsorb on the (101) and (110) planes of hexagonal close-packed cobalt (HCP-Co) due to their differential adsorption energies. This selective suppression promotes preferential growth along the densely packed (002) orientation. This leads to a trench-filling process dominated by the most densely packed plane, resulting in better electrical performance. Superfilling is achieved when molecular adsorption energies are in the range of 5-8 eV. The work establishes a functional group design strategy to regulate additive adsorption, enabling crystallographic control for advanced cobalt electrodeposition processes.
由于电子平均自由程和电迁移的影响，铜互连技术面临局限性，这推动了钴替代物的采用。本研究提出了一种新颖的机制，通过调节添加剂分子在钴表面的吸附能来实现超填充。通过改变具有不同官能团的分子结构来调整添加剂的吸附能。计算结果表明，碳 - 碳三键显著增强吸附，而醚键进一步增强在不同钴晶体学平面上的结合。具体而言，同时含有三键和醚基的1,4 - 双（2 - 羟基乙氧基） - 2 - 丁炔（BEO）表现出最高的吸附能（-22.62 eV）。在2 - 丁炔 - 1,4 - 二醇（BOZ）中用羟基取代醚基会将吸附能降低至 -10.39 eV，而在1,4 - 丁二醇二缩水甘油醚（BDE）中消除三键会进一步将其降低至 -8.43 eV。实验研究表明，由于BOZ和BEO的吸附能不同，它们优先吸附在六方密堆积钴（HCP - Co）的（101）和（110）平面上。这种选择性抑制促进了沿密集堆积的（002）取向的优先生长。这导致了由最密集堆积平面主导的沟槽填充过程，从而产生更好的电性能。当分子吸附能在5 - 8 eV范围内时实现超填充。这项工作建立了一种官能团设计策略来调节添加剂吸附，从而实现对先进钴电沉积过程的晶体学控制。
