• Laser Solutions
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• v.8 no.2
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• pp.7-12
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• 2005

The material processing of UV nanosecond pulse laser cannot be avoided the material shape change and contamination caused by interaction of base material and laser beam. Nowadays, ultra short pulse laser shorter than nanosecond pulse duration is used to overcome this problem. The advantages of this laser are no heat transfer, no splashing material, no left material to the adjacent material. Because of these characteristics, it is so suitable for micro material processing. The processing of sapphire wafer was done by UV 355nm, green 532nm, IR 1064nm. X-Y motorized stage is installed to investigate the proper laser beam irradiation speed and cycles. Also, laser beam fluence and peak power are calculated.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.11a
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• pp.303-304
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• 2008

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2004.05b
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• pp.324-326
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• 2004

We have obtained ultra-short pulses with a wavelength of 616 nm from a Distributed Feedback Dye Laser pumped by excimer laser. Using the second harmonic generation, we obtained ultra-short pulse at 308nm in ultraviolet region and also performed amplification in 3 stages of XeCl amplifiers.

• Journal of the Semiconductor & Display Technology
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• v.6 no.1 s.18
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• pp.11-15
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• 2007

Low-k wafer engraving process has been investigated by using UV pico-second laser with high repetition rate. Wavelength and repetition rate of laser used in this study are 355 nm and 80 MHz, respectively. Main parameters of low-k wafer engraving processes are laser power, work speed, assist gas flow, and protective coating to eliminate debris. Results show that engraving qualities of low-k layer by using a laser with UV pico-second pulse width and high repetition rate had better kerf edge and higher work speed, compared to one by conventional laser with nano-second pulse width and low repletion rate in the range of kHz. Assist gas and protective coating to eliminate debris gave effects on the quality of engraving edge. Total engraving width and depth are obtained less than $20\;{\mu}m$ and $10\;{\mu}m$ at more than 500 mm/sec work speed, respectively. We believe that engraving method by using UV pico-second laser with high repetition rate is useful one to give high work speed in laser material process.

• Proceedings of the Korean Society of Laser Processing Conference
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• 2006.11a
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• pp.128-132
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• 2006

Low-k wafer engraving process has been investigated by using UV pico-second laser with high repetition rate. Wavelength and repetition rate of laser used in this study are 355nm and 80MHz, respectively. Main parameters of low-k wafer engraving processes are laser power, work speed, assist gas flow rate, and protective coating to eliminate debris. Results show that engraving qualities of low-k layer by using UV pico-second pulse width and high repetition rate had better kerf edge and higher work speed, compared to one by conventional laser with nano-second pulse width and low repetition rate in the range of kHz. Assist gas and protective coating to eliminate debris gave effects on the quality of engraving edge. Total engraving width and depth are obtained less than $20{\mu}m$ and $10{\mu}m$ at more than 500mm/sec work speed, respectively. We believe that engraving method by using UV pico-second laser with high repetition rate is useful one to give high work speed of laser material process.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.9 no.3
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• pp.56-61
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• 2010

Recently, UV pulse laser is widely used in micro machining of the research, development and industry field of IT, NT and BT products because the laser short wavelength provides not only micro drilling, micro cutting and micro grooving which has a very fine line width, but also high absorption coefficient which allows a lot of type of materials to be machined more easily. To analyze the dynamic deformation during a very short processing time, which is nearly about several tens nanoseconds, the commercial Finite Element Analysis (FEA) code, LS-DYNA 3D, was employed for the computitional simulation of the UV laser micro machining behavior for thin copper material in this paper. A finite element model considering high strain rate effect is especially suggested to investigate the micro phenomena which are only dominated by mechanically pressure impact in disregard of thermally heat transfer. From these computational results, some of dynamic deformation behaviors such as dent deformation shapes, strains and stresses distributions were observed and compared with previous experimental works. These will help us to understand micro interaction between UV laser beam and material.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.287-288
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• 2010

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.299-300
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• 2010

• Journal of the Korean Society for Precision Engineering
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• v.27 no.2
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• pp.20-24
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• 2010

High speed cutting processes of rigid flexible printed circuit board by making use of high power UV laser with nano-second pulse width have been proposed and investigated experimentally. Also robust laser cutting system has been designed and developed in order to obtain a good cutting quality of rigid and flexible PCB with multi-layers (2-6 layers). Power controller module developed for ourselves is adapted to control the laser output power in the range less than 1%. The systems show the good performance of cutting speed, cutting width and cutting accuracy, respectively. Especially we have confirmed that the short circuit problem due to the carbonized contamination occurred in cross section of multi-layers by thermal effect of high power laser has been improved largely by using multi-pass cutting process with low power and high speed.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.10
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• pp.23-28
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• 2010

Resistance trimming and cutting processes of printed circuit board by making use of high power UV laser with nano-second pulse width have been proposed and investigated experimentally. Also laser-based application system with high flexibility and complex has been designed and adopted power controller, auto beam size control, auto-focusing and control program developed for ourselves. The function of each module shows that they can be reliable for industrial equipments. Resistance trimming method used a plunge and double cut process with $20{\mu}m$ spot size beam. Results show that double cut process is more effective to control resistance trimming in precision than plunge cut process.