Design and fabrication of micro and nano surface structures for enhancing metal–polymer adhesion using femtosecond laser treatment

Masaki Omiya, Ayumi Nakajima, Jiwang Yan

Research output: Contribution to journalArticlepeer-review

Abstract

This study investigated the effects of micro- and nanostructures on the adhesion strength between copper and an encapsulating mold compound (EMC). The shape of the microgrooves was designed based on fracture mechanics theory, and the effect of laser-induced periodic structure surface (LIPSS) formation on the microgroove was investigated using numerical simulations. The designed surface profiles were fabricated using femtosecond laser treatments, and the adhesion strength between copper and the EMC was evaluated. The results show that deep microgrooves improved the adhesion strength owing to the anchor effect. However, the aspect ratio between the pitch and depth of the microgroove had a limitation in enhancing the adhesion strength. The formation of LIPSSs on the mountaintop of the microgroove was very effective; however, an LIPSS on the valley of the microgroove was ineffective. Numerical analyses revealed that LIPSSs suppressed the shear deformation of the EMC and worked as resistance to interface delamination. Based on the findings obtained in this study, combining micro- and nano-scale surface structure formation with femtosecond laser treatments is an effective and eco-friendly method for improving adhesion strength.

Original languageEnglish
Article number111349
JournalMaterials and Design
Volume224
DOIs
Publication statusPublished - 2022 Dec

Keywords

  • Adhesion strength
  • Copper
  • Electronic packaging
  • LIPSS
  • Laser
  • Micro and nano surface structures
  • Surface treatment

ASJC Scopus subject areas

  • Materials Science(all)
  • Mechanics of Materials
  • Mechanical Engineering

Fingerprint

Dive into the research topics of 'Design and fabrication of micro and nano surface structures for enhancing metal–polymer adhesion using femtosecond laser treatment'. Together they form a unique fingerprint.

Cite this