随着超大规模集成电路的发展，器件特征尺寸不断缩小，必然会出现Cu互连扩散阻挡层厚度无法进一步减小等瓶颈问题。因此，开发新型无扩散阻挡层Cu合金薄膜（Cu种籽层）势在必行。该新型互连结构在长时间的中高温（400~500 ℃）后续工艺实施过程中，需同时具备高的稳定性（不发生互扩散反应）和低的电阻率。基于此，首先综述了目前无扩散阻挡层结构的研究现状及问题，然后对基于稳定固溶体团簇模型设计制备的无扩散阻挡Cu-Ni-M薄膜的研究工作进行了梳理，通过多系列薄膜微观结构、电阻率及稳定性的对比，深入探讨了第三组元M的选择原则及其对薄膜热稳定性的影响。为进一步验证稳定固溶体团簇模型的有效性，对第二组元的变化进行了相关讨论。结果证实，选取原子半径略大于Cu、难扩散且难溶的元素作为第三组元M，薄膜表现出良好的扩散阻挡能力；当M/Ni=1/12，即合金元素完全以团簇形式固溶于Cu基体时，薄膜综合性能达到最优，能够满足微电子行业的要求。所有研究表明，稳定固溶体团簇模型在无扩散阻挡层Cu合金薄膜的成分设计方面十分有效，该模型也有望在耐高温Cu合金及抗辐照材料成分设计方面推广使用。

With the development of ultra-large-scale integrated circuits, a bottleneck problem will eventually appear due to further shrinking of device feature sizes, which is the thickness of Cu interconnect diffusion barrier layer fail to continuously reducing. Therefore, it is imperative to develop a new barrierless structure Cu alloy thin film (Cu seed layer), that needs keeping high stability (no interdiffusion occurs) and low resistivity in a moderate temperature environment (400~500 ℃) of subsequent processes for a long period. In present paper, the current state and problem of the barrierless structures were summarized firstly. Then, the research work of the barrierless Cu-Ni-M films based on the stable solid solution cluster model was reviewed, and the selection principle of the third element M and its influence on the thermal stability were discussed through the comparison of the microstructure, resistivity and stability of the multi-series films. Finally, the changes of the second element were discussed to further verify the validity of the stable solid solution cluster model. The results show that the films have excellent ability to inhibit diffusion under the condition of the third element M with a slightly larger atomic radius than Cu and difficult to diffuse and insoluble in Cu. When M/Ni=1/12, i.e., the alloying elements are completely dissolved into the Cu matrix in the form of clusters, the comprehensive performance of the film reaches the optimal, which can meet the requirements of the microelectronics industry. All these studies indicate that the stable solid solution cluster model is very effective in the composition design of the barrierless Cu thin film, and this model is also expected to be widely used in the composition design of high temperature resistant Cu alloy and radiation resistant materials.