Laser drilling of copper foils for electronics applications

C. J. Moorhouse, Francisco J. Villarreal, Howard J. Baker, Denis R. Hall

Research output: Contribution to journalArticle

Abstract

Single pulse drilling of copper foils and copper-coated dielectric circuit board materials, relevant to applications in micro-electronics packaging, has been investigated here using an enhanced peak power CO2-laser. The plasma generated during copper laser ablation, under these conditions, has been found to be self-extinguishing once the copper has been punched through, and does not materially impact the process. The analysis of the undercut formation in the copper coated laminates illustrated a direct link with the energy delivered to the dielectric after the copper has been laser ablated. Holes with zero undercut were obtained by the use of an acousto-optic modulator, used as a pulse shutter, to control the energy delivered to the dielectric. For unmodulated laser pulses, holes with zero undercut were obtained when drilling copper foils 35-µm thick. In general, when drilling copper-coated dielectrics with unmodulated pulses, holes with low undercut were obtained for peak powers < 1.2 kW. However, the stochastic nature of copper drilling dominates the process in this regime. At higher peak powers (up to 1.8 kW), a yield of 100% holes in copper is obtained, but this also results in significant undercut. © 2007 IEEE.

Original languageEnglish
Pages (from-to)254-263
Number of pages10
JournalIEEE Transactions on Components and Packaging Technologies
Volume30
Issue number2
DOIs
Publication statusPublished - Jun 2007

Fingerprint

laser drilling
foils
copper
electronics
drilling
pulses
extinguishing
lasers
electronic packaging
shutters
acousto-optics
circuit boards
microelectronics
laminates
laser ablation
modulators

Keywords

  • Carbon dioxide (CO 2 ) lasers
  • Copper
  • Laser drilling
  • Microvia
  • Resin coated copper (RCC)

Cite this

Moorhouse, C. J. ; Villarreal, Francisco J. ; Baker, Howard J. ; Hall, Denis R. / Laser drilling of copper foils for electronics applications. In: IEEE Transactions on Components and Packaging Technologies. 2007 ; Vol. 30, No. 2. pp. 254-263.
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Laser drilling of copper foils for electronics applications. / Moorhouse, C. J.; Villarreal, Francisco J.; Baker, Howard J.; Hall, Denis R.

In: IEEE Transactions on Components and Packaging Technologies, Vol. 30, No. 2, 06.2007, p. 254-263.

Research output: Contribution to journalArticle

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