XRD and ToF-SIMS study of intermetallic void formation in Cu-Sn micro-connects

Research output: Contribution to journalArticleScientificpeer-review

Researchers

Research units

  • Fraunhofer Institute for Microstructure of Materials and Systems IMWS

Abstract

An identified reliability challenge of significant importance to Cu-Sn bonding for 3D integration is Cu-Sn intermetallic void formation. Voids, often referred to as Kirkendall voids, form within the inter-diffusional zone between Cu and Sn, more specifically within the intermetallic compound Cu3Sn. The root-cause(s) of void formation is not well understood, therefore this study is designed to understand under what conditions voids form. The two main hypotheses for the root-causes of void formation are (i) the imbalance of diffusion rates between Cu and Sn during the formation of Cu-Sn intermetallic compounds and the resulting residual stresses and (ii) the co-deposition of impurities during Cu electroplating to void formation. Therefore, an ex- and in-situ x-ray diffraction (XRD) study is used to probe the material state as a function of thermal annealing, and a time-of-flight mass spectroscopy (ToF-SIMS) study is used to detect impurities co-deposited during Cu electroplating and to understand the effects of thermal annealing on the impurities' kinetic behaviour.

Details

Original languageEnglish
Pages (from-to)390-394
JournalMicroelectronics Reliability
Volume76-77
Publication statusPublished - 2017
MoE publication typeA1 Journal article-refereed

    Research areas

  • 3D integration, Intermetallic voids, Kirkendall voids, Reliability, Time-of-flight mass spectroscopy, X-ray diffraction

ID: 14527389