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Proceedings Paper

Enhanced peak power CO2 laser processing of PCB materials
Author(s): C. J. Moorhouse; F. Villarreal; J. J. Wendland; H. J. Baker; D. R. Hall; D. P. Hand
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Paper 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.

Paper Details

Date Published: 8 June 2005
PDF: 7 pages
Proc. SPIE 5827, Opto-Ireland 2005: Photonic Engineering, (8 June 2005); doi: 10.1117/12.605096
Show Author Affiliations
C. J. Moorhouse, Heriot Watt Univ. (United Kingdom)
F. Villarreal, Heriot Watt Univ. (United Kingdom)
J. J. Wendland, Heriot Watt Univ. (United Kingdom)
H. J. Baker, Heriot Watt Univ. (United Kingdom)
D. R. Hall, Heriot Watt Univ. (United Kingdom)
D. P. Hand, Heriot Watt Univ. (United Kingdom)

Published in SPIE Proceedings Vol. 5827:
Opto-Ireland 2005: Photonic Engineering
Thomas J. Glynn; John T. Sheridan; Brian W. Bowe; Ronan F. O'Dowd; Gerard M. O'Connor; Aidan J.H. Flanagan; Gerard D. O'Sullivan; Gerald Byrne; Jonathan Magee, Editor(s)

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