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Laser Drilling of a 7-layer Flexible Printed Circuit Board using a
Pulsed Ytterbium Fiber Laser System
Chih-Chung Yang, Yi-Cheng Lin, Tzu-Chieh Peng, Kuo-Cheng Huang and Yu-Hsuan Lin
*
Instrument Technology Research Center, National Applied Research Laboratories, Hsinchu, Taiwan
Keywords: Laser Drilling, Trepanning, FPCB, Pulsed Fibre Laser.
Abstract: Recently, laser-processing industry is becoming increasingly popular because of its advantages of low cost,
fast and good energy efficiency. The electric circuit board manufacturers also began to import related laser
processing technology to improve the productivity. This paper presents the laser drilling process and quality
analysis of the 7-layer flexible printed circuit (FPCB). A laser drilling system pulsed Ytterbium fiber laser,
expander device, focal lens, galvanometric scanner and XY-axis manual stage was used to perform the hole
cutting of the multilayer-layer FPCB. This study succeeded in establishing a comparing procedure, which
enabled the characteristic comparison between the various experimental conditions. We believe that this
study provides a useful database for FPCB drilling technology.
1 INTRODUCTION
Laser is a kind of modern light source, which emits
light when a driving voltage is applied. The light is
amplified by a process of the stimulated emission of
electromagnetic radiation. The optical properties of
laser are monochromatic, coherent, collimated and
polarizable. In recent years, laser industry becomes
increasingly popular because of the demand of high
manufacturing efficiency for various products. Due
to the advantage of high power intensity, long
lifetime, low power consumption, good luminous
efficiency, faster switching and small size, the laser
technology has gradually replaced the traditional
optical lighting and mechanical processing.
Nowadays, laser has been widely used in optical
measurement, precision machining, bio-treatment,
image projection and versatile sample excitation
applications (Malcolm, 2000) (Winco, 2000) (Han-
Chao, 2015) (Surmann, 2003) (Seokbae, 2002).
Among them, the most popular is precision
machining. Due to the high collimation of the laser,
the focused spot can be very small. In other words,
the energy dose is quite high. The melting and
vaporization processing can be carried out in a small
area of the sample. It means that the resolution of
laser processing is very high. The laser processing
material is not limited to metal, and can be glass,
wood, ceramics, plastic and paper. For the cutting,
engraving or welding application, the typical lasers
are CO2 laser, Nd:YAG laser, semiconductor laser
and fiber laser etc. Recently, due to the rise of
mobile devices, the demand for laser-processing the
small circuit boards is rapidly growing. Therefore,
the electric circuit board manufacturers also began to
import related laser processing technology.
For the printed circuit board manufacturing
industry, laser direct cutting and drilling is the most
popular (Ching-Ching, 2017) (Hsin-Yi, 2016)
(Kestenbaum, 1990) (Avanish, 2008) (Winco, 2007)
(Reinhart, 2010) (Owen, 1998). Because the novel
printed circuit board has high conductive wiring
density, small holes and contacts, the resolution of
the traditional mechanical processing is obviously
insufficient. Also, mechanical cutting is also easy to
damage the printed circuit board. The most common
samples recently are soft-matter printed circuit board
and high density inter-connect (HDI) printed circuit
board. In order to improve the processing accuracy
and stability, laser ablation gradually replaced the
mechanical processing. Laser ablation has the
advantages of simple, high-resolution and rapid. It
cannot only accurately control the ablation depth and
the size, but also prevent overheat and maintain the
results quality. The type of laser light source can
determine the ablation characteristic. For example,
because the power of CO2 laser is very high, the
action of laser ablation is rapid. However, its long
wavelength leads to low resolution. Therefore, this
178
Yang, C-C., Lin, Y-C., Peng, T-C., Huang, K-C. and Lin, Y-H.
Laser Drilling of a 7-layer Flexible Printed Circuit Board using a Pulsed Ytterbium Fiber Laser System.
DOI: 10.5220/0006613801780184
In Proceedings of the 6th International Conference on Photonics, Optics and Laser Technology (PHOTOPTICS 2018), pages 178-184
ISBN: 978-989-758-286-8
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