Evolution of the grain size gradient and its effect on the mechanical and electrical properties of metal interconnects. (15th November 2022)

• Record Type: Journal Article
• Authors: Zhang, Hengjia; Zhang, Xiaomin; Zhao, Zhipeng; Tang, Hongwu; Zhao, Bo
• Is Part Of: Materials science in semiconductor processing. Volume 151(2022)
• Publication Date: 2022-11-15
• Subjects: Grain size gradient -- Phase field model -- Electromigration -- Constitutive model -- Resistivity; Semiconductors -- Periodicals; Integrated circuits -- Materials -- Periodicals; Semiconducteurs -- Périodiques; Circuits intégrés -- Matériaux -- Périodiques; Electronic journals; 621.38152
• DOI: 10.1016/j.mssp.2022.107046
• Languages: English
• ISSNs: 1369-8001

Abstract

Abstract: For metal interconnects under high current density, this work aims to study the evolution of the grain size gradient and its impact on the mechanical and electrical properties at both the micro and macro levels. A potential accelerated test method incorporating multistage electromigration is proposed to achieve a gradient distribution of grain size. A phase field grain growth model incorporating electromigration and strain is used to investigate the path and mechanism of grain gradient evolution. For the prepared gradient structure models, the numerical assessment of mechanical properties and the electrical properties are implemented by a generalized constitutive model based on the grain size distribution and dislocation density, and the Matthiessen criterion, respectively. The comparison with experimental results shows that the evaluation methods are reliable. The calculation results indicate that the strength of the gradient microstructure can be elevated without the loss of ductility. The resistivity of the stabilized gradient structure is only reduced by 0.06% compared with that of the original uniform structure. This shows that the refined grain layer ensures the strength of the metal interconnect structure, while the coarse grain layer maintains good electrical conductivity.