Preparation of preferentially oriented thin film interconnect on SiOィイD22ィエD2

SiO2D22 上择优取向薄膜互连的制备

• 批准号: 10650300
• 负责人: NOYA Atsushi
• 金额: $ 1.92万
• 依托单位: Kitami Institute of Technology
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1998
• 资助国家: 日本
• 起止时间: 1998 至 1999
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10650300/
• 关键词: LSI; Preferential orientation; interconnect; diffusion barrier; Cu; Nb; V; Ta-W alloy; 集積回路; 高配向薄膜; LSI; Preferential orientation; interconnect; diffusion barrier; Cu; Nb; V; Ta-W alloy; 集積回路; 高配向薄膜

The Cu interconnect in Si-LSI has been fabricated with a diffusion barrier in the ditch of SiOィイD22ィエD2 by the so-called damascene process. For the Cu interconnect technology, (1) a preferential orientation of Cu (111) plane is desired for suppressing an electromigration failure, and (2) an effective diffusion barrier is also desired as thin as possible. The diffusion barrier materials, which satisfy these issues, are examined in the present study. Transition metal of Nb or V, which is in the bcc structure, is applied as a diffusion barrier between Cu and SiOィイD22ィエD2. The results show that the preferential orientation of Cu (111) is obtained onto the Nb or V(110) oriented barrier formed on the amorphous SiOィイD22ィエD2 layer. The interconnect system with these barriers is found to be difficult to form the thin barrier due to the diffusion of barrier materials through the Cu layer and the reaction at the barrier/SiOィイD22ィエD2 interface. For the formation of thin barrier, NbN or VN is applied to the diffusion barrier. Thermally stable thin barrier is obtained in the Cu/VN(10 nm)/SiOィイD22ィエD2 system, however, Cu(111) orientation in the system is inferior to that using a Nb or V barrier. The barrier of Ta-W solid solution maintaining a bcc structure is then applied as a barrier in the above-mentioned system. This system configuration realizes the Cu (111) preferential orientation on the Ta-W (110) barrier, and shows an excellent thermal stability suppressing the diffusion and reaction observed in the system with Nb or V barrier even at a barrier of 20 nm thick. We can achieve the formation of thermally stable thin barrier layer between Cu and SiOィイD22ィエD2 by using Ta-W alloy films with a suitable composition.

Si-LSI中的CU互连已通过所谓的Damascene工艺在SIOI D22沟中用扩散屏障制造。对于CU互连技术，（1）需要使用Cu（111）平面的优选方向来抑制电迁移失败，并且（2）也需要尽可能薄地进行有效的扩散屏障。在本研究中检查了满足这些问题的扩散屏障材料。在BCC结构中的NB或V的过渡金属被用作CU和SIOI D22之间的扩散屏障。结果表明，在在无定形SIOI D22层上形成的NB或V（110）面向屏障上获得了Cu（111）的首选方向。由于屏障材料通过CU层的扩散以及在屏障/SIOI D22界面处的反应，因此发现与这些屏障的互连系统很难形成薄屏障。为了形成薄屏障，将NBN或VN应用于扩散屏障。在CU/VN（10 nm）/SIOI D22系统中获得热稳定的薄屏障，但是系统中的Cu（111）方向不如使用NB或V屏障的Cu（111）。然后，将维持BCC结构的TA-W固体溶液的屏障作为屏障应用在上述系统中。该系统配置实现了TA-W（110）屏障上的Cu（111）优先取向，并显示出极好的热稳定性，即使在20 nm厚的屏障中，也可以在系统中观察到的NB或V屏障在系统中观察到的扩散和反应。通过使用具有合适组成的Ta-W合金膜，我们可以实现CU和SIOI D22之间的热稳定薄壁层的形成。