基于石墨烯/Cu的密集硅通孔结构制备和性能调控

With the IC feature sizes shrinking, the via in 3D-TSV interconnection becomes highly dense and complex. Cu-TSV using cooper as the filler will bring several challenges. According to the requirements of 3D-TSV technology in the 22/16nm node, we proposed a novel TSV structure using the Multilayer Doped graphene (MLDG) as a transition layer. Due to its outstanding thermal, mechanical and material properties of graphene, the MLDG can reduce the thermal stress mismatch between the Si(SiO2) and the cooper filler, and improve the thermal dissipation in TSVs. Moreover, the MLDG acts as the barrier layer preventing the diffusion of cooper atoms to the main body of Si/SiO2. The doped graphene layers with excellent conductivity are used as the signal transmission path. The combination of MLDG and cooper filler reduces the impact of skin effect, electro- and stress- migration on the increase of resistance. The MLDG/Cu TSV would also have a ranking performance for high-frequency signal transmission, which solves the key technical problems in 3D-TSV development and provides new ideas for IC design, manufacturing and performance analysis.

随着IC特征尺寸不断缩减，3D-TSV互连通道将变成高度密集且十分复杂的三维微结构群, 以Cu为填充材料的Cu-TSV将面临诸多挑战。本项目从22/16nm节点下3D-TSV互连填充工艺及特性出发，结合当前制造工艺水平，利用碳纳米材料良好的热力学、机械和材料特性，提出了以多层掺杂石墨烯（MLDG）为过渡层的Cu-TSV新结构，在热膨胀系数差异较大的Si(SiO2)和Cu之间加入MLDG纳米层，减小不同材料之间的热应力失配情况，利用石墨烯层优异的导热性，提高TSV的散热性能；MLDG同时作为阻挡层，防止Cu原子向本体扩散；通过掺杂工艺提高石墨烯层的导电性能，以MLDG+Cu作为TSV信号传输通道，弥补Cu因趋肤效应、电迁移和应力迁移等引起的阻值增大，改善其高频信号传输性能，以期解决3D-TSV发展的关键技术难题，为新技术节点下的IC结构设计，工艺制备和性能分析提供新的思路。

本项提出了一种以碳纳米材料为过渡层的TSV新结构，在热膨胀系数差异较大的硅/铜之间加入碳纳米材料层，减小不同材料之间的热应力失配情况，利用碳纳米材料优异的导热性，提高TSV的散热性能；以碳纳米材料层作为TSV信号传输辅助通道，弥补Cu因趋肤效应、电迁移和应力迁移等引起的阻值增大，改善了其高频信号传输性能。项目研究制备了基于碳纳米材料的硅通孔新结构，揭示了碳纳米材料在密集深沟槽结构中生长机理，建立了TSV新结构的热应力跨尺度演变模型，研究了TSV微结构的应力产生、释放、及热应力失配引起结构失效机理；揭示了碳纳米材料辅助导电层对铜TSV电磁性能，包括趋肤效应，电磁分布的影响规律。通过数值计算、建模仿真和实验对其热、电、磁性能进行了分析与验证，结果表明基于碳纳米材料的TSV新结构热电磁性能远优于传统结构。项目研究为新技术节点下TSV结构的传热、导电及高频电磁耦合提供了一种新的方法和技术。