Investigative characterization of delamination at TiW-Cu interface in low-temperature bonded interconnects

Obert Golim*, Vesa Vuorinen, Glenn Ross, Sami Suihkonen, Mervi Paulasto-Kröckel

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

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Abstract

The trend for heterogeneous integration has driven the need for a low-temperature bonding process. Cu-Sn-In based solid-liquid interdiffusion (SLID) bonding technology has been presented as a viable option. However, previous studies have also reported that issues might exist in the interconnect interface towards the substrate, leading to the formation of intermetallic layers at undesired locations. This study carried out a series of characterization methods to determine the root cause of this issue. Cross-sectional observations showed that the problem occurs particularly at the TiW-Cu interface. Examination of the adhesion layer showed possible impurities existing in the layers, compromising its adhesion to copper. Residual stress analyses displayed opposing loading conditions at the interface. The interplay of the two factors resulted in the delamination of the TiW-Cu interface, leading to a pathway for Sn–In atoms. Furthermore, several methods are proposed to mitigate this issue.

Original languageEnglish
Article number113772
JournalMaterials Characterization
Volume209
DOIs
Publication statusPublished - Mar 2024
MoE publication typeA1 Journal article-refereed

Keywords

  • Delamination
  • Interconnect
  • Interface
  • SLID

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