Laser-assisted via hole metallization in PCB materials

K. Kordás, J. Békési, R. Vajtai, M. Jauhianen, J. Remes, A. Uusimaki, S. Leppävuori, T. F. George, L. Nánai

Research output: Contribution to journalLetter

12 Citations (Scopus)

Abstract

A novel via hole metallization method is presented, where the vias are drilled in polyimide/copper (PI/Cu) flexible printed circuit boards (PCBs) using KrF excimer pulses, and then pre-metallized using a scanned Ar+ laser. In the pre-metallization step, a thin (20-50 nm) and narrow (2-10 μm) palladium layer is deposited on the polyimide-covered side of the PCB and on the wall of the vias using the laser-induced chemical liquid-phase deposition method. After the pretreatment, the Pd covered holes are immersed into a Cu electroless plating bath. Plated copper vertical and horizontal interconnects are analyzed by optical microscopy, focused ion beam, profilometry and resistivity measurements. The results show that the copper deposits formed on the pre-metallized surface of PCBs have high chemical purity, excellent adhesion and almost bulk conductivity, but, so far, due to unclear reasons, high through hole resistance.

Original languageEnglish
Article number99
Pages (from-to)L21-L24
JournalJournal of Electronic Materials
Volume30
Issue number5
DOIs
Publication statusPublished - Jan 1 2001

Keywords

  • PCB materials
  • Pd
  • Via hole metallization

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Electrical and Electronic Engineering
  • Materials Chemistry

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    Kordás, K., Békési, J., Vajtai, R., Jauhianen, M., Remes, J., Uusimaki, A., Leppävuori, S., George, T. F., & Nánai, L. (2001). Laser-assisted via hole metallization in PCB materials. Journal of Electronic Materials, 30(5), L21-L24. [99]. https://doi.org/10.1007/s11664-001-0099-7