Enhanced peak power CO2 laser processing of PCB Materials

C. J. Moorhouse, F. Villarreal, J. J. Wendland, H. J. Baker, D. R. Hall, D. P. Hand

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)

Abstract

Laser drilling has become a common processing step in the fabrication of printed circuit boards (PCB's). For this work, a recently developed enhanced peak power CO2 laser (~2.5 kW peak power, 200W average) or ultra-super pulse (USP) laser is used to drill alumina and copper coated dielectric laminate materials. The higher peak power and faster response times (than conventional CO2 lasers) produced by the USP laser are used to produce high speed alumina laser scribing and copper coated laminate microvia drilling processes. Alumina is a common PCB material used for applications, where its resistance to mechanical and thermal stresses is required. Here we present a comprehensive study of the melt eject mechanisms and recast formation to optimise the speed and quality of alumina laser scribing. Scribe speeds of up to 320 mms-1 (1.8 times current scribe rate) have been achieved using novel temporal pulse shapes unique to the USP laser. Also presented is the microvia drilling process of copper dielectric laminates, where the multi-level configuration presents different optical and thermal properties complicating their simultaneous laser ablation. In our experiments the USP laser has been used to drill standard thickness copper films (up to 50 µm thick) in a single shot. This investigation concentrates on understanding the mechanisms that determine the dielectric undercut dimensions.

Original languageEnglish
Article number44
Pages (from-to)438-444
Number of pages7
JournalProceedings of SPIE - the International Society for Optical Engineering
Volume5827
DOIs
Publication statusPublished - 2005
EventOpto-Ireland 2005: Photonic Engineering - Dublin, Ireland
Duration: 4 Apr 20056 Apr 2005

Keywords

  • Alumina
  • CO 2 laser
  • High speed videography
  • Melt ejection
  • Resin coated copper

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