Evolution mechanism of interconnect interface and shear properties of 64.8Sn35.2Pb microbump during flip chip bonding

Yu Lu Shen, Jiao Luo, Keng Feng Xu, Dao Wei Wu, Ning Zhang

Research output: Contribution to journalArticlepeer-review

Abstract

Effect of flip chip bonding parameters on microstructure at the interconnect interface and shear properties of 64.8Sn35.2Pb microbumps were investigated in this work. Results show that the main intermetallic compound (IMC) at the interconnect interface is (Ni, Cu)3Sn4 phase, and meanwhile a small amount of (Cu, Ni)6Sn5 phase with a size of 50–100 nm is formed around (Ni, Cu)3Sn4 phase. The orientation relationship of [1¯5¯6](Ni, Cu)3Sn4//[152](Cu, Ni)6Sn5 and (601)(Ni, Cu)3Sn4//(2¯01)(Cu, Ni)6Sn5 is found between these two phases, and the atomic matching at the interface of the two phases is low. The highest shear force of 77.3 gf is achieved in the 64.8Sn35.2Pb microbump at the peak temperature of 250 °C and parameter V1 because dense IMCs and no cracks form at the interconnect interface. Two typical fracture modes of microbumps are determined as solder fracture and mixed fracture. The high thermal stress presenting in the thick IMCs layer induces crack initiation, and cracks propagate along the α/β phase boundaries in the Sn-Pb solder under shear force, leading to a mixed fracture mode in the microbumps.

Translated title of the contribution倒装焊 64.8Sn35.2Pb 微凸点互连界面演化机理与剪切性能
Original languageEnglish
Pages (from-to)1284-1298
Number of pages15
JournalJournal of Central South University
Volume32
Issue number4
DOIs
StatePublished - Apr 2025

Keywords

  • flip chip bonding
  • intermetallic compound
  • microbump
  • orientation relationship
  • shear properties
  • Sn-Pb

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