2022 Fiscal Year Final Research Report

Investigation of damage mechanism of metal nanoparticle interconnect used in flexible electronic circuits under electrical and mechanical loadings

Research Project

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Project/Area Number	19K04084
Research Category	Grant-in-Aid for Scientific Research (C)
Allocation Type	Multi-year Fund
Section	一般
Review Section	Basic Section 18010:Mechanics of materials and materials-related
Research Institution	Hirosaki University
Principal Investigator	SASAGAWA Kazuhiko 弘前大学, 理工学研究科, 教授 (50250676)
Project Period (FY)	2019-04-01 – 2023-03-31
Keywords	金属ナノ粒子配線 / エレクトロマイグレーション / フレキシブル回路 / 信頼性
Outline of Final Research Achievements	The followings were shown for the first time in the world; In the flexible silver nanoparticle lines under electrical and mechanical loadings, the local decrease in line’s thickness by the formation of the metal particles aggregates on the line and electromigration, EM, was the complex damage factor, and as EM damage mechanism, the porous internal structure of the line changes, the aggregates of silver particles like a crystal grain were formed with electrical loading, and the metallic atoms diffused along the grain boundary by electromigration. In general EM damage, the damage by the grain boundary diffusion occurred on the cathode side of the line, but the damage occurred on the anode side in the silver nanoparticles lines. Thus, it was revealed that it was necessary to build an atomic diffusion model in consideration of inhomogeneity of the crystal grain size in the line’s internal structure to reproduce this phenomenon, and the theoretical model was immediately started to build.
Free Research Field	材料システム評価学
Academic Significance and Societal Importance of the Research Achievements	これまで明らかになっていないフレキシブル金属ナノ粒子インク配線の高密度電子流による損傷に焦点を絞り、特に実用環境で想定される電気負荷と応力負荷が重畳作用する複雑な損傷の初生および進展機序を世界に先駆け解明したものであり、学術的な意義を有する。さらに、損傷機構の解明にとどまらず、これまで成功をみていない金属ナノ粒子インク配線の強度評価へ歩を進めたことは、今後発展が望まれる柔らかい電子回路の信頼性を確保することに貢献し、これによるさらなる応用分野の拡大が見込まれ、その社会的意義は大きい。