• Journal of the Korean Society for Precision Engineering
• /
• v.27 no.6
• /
• pp.32-38
• /
• 2010

Laser material processing technology is adopted in several industry as alternative process which could overcome weakness and problems of present adopted process, especially semiconductor and display industry. In semiconductor industry, laser photo lithography is doing at front-end level, and cutting, drilling, and marking technology for both wafer and EMC mold package is adopted. Laser cleaning and de-flashing are new rising technology. There are 3 kinds of main display industry which use laser technology - TFT LCD, AMOLED, Touch screen. Laser glass cutting, laser marking, laser direct patterning, laser annealing, laser repairing, laser frit sealing are major application in display industry.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2005.10a
• /
• pp.502-505
• /
• 2005

To overcome some of the limitations in the conventional photolithography technique, MC-SPL which has advantages such as flexibility and high speed was developed in the past. To make a fine pattern using MC-SPL, there are many variables to control, for example, applied load, scribing speed, chemical etching condition, and etc. In this work, the effect of contact load on the width of the pattern was investigated. The load not only influences the width of the pattern but it also affects the wear of the probe tip. It was found that it is beneficial to load the tip in two stages. Futhermore, the experimental results showed that the pattern width was more sensitive to the initial contact force.

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

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.33 no.1
• /
• pp.10-15
• /
• 2020

Recently, with the increase in the use of urban solar power, solar modules are required to produce high power in limited areas. In this report, we proposed the fabrication of a high-power photovoltaic module using shingles technology, and developed accurate string characteristic simulations based on circuit modeling. By comparing the resistance components between the interconnected cells and the cell strips, the ECA resistance was determined to be 0.003 Ω. Based on the equivalent circuit of the modeled shingled string, string simulation was performed according to the type of cell strip. As a result, it was determined that the cell efficiency of the 4-cell strip was the highest at 19.66%, but the efficiency of the string simulated with the 6-cell strip was the highest at 20.48% in the string unit.

• Journal of the Korean Society for Precision Engineering
• /
• v.22 no.12 s.177
• /
• pp.184-189
• /
• 2005

An experimental study of the femtosecond laser machining of Si materials was carried out. Direct laser machining of the materials for the feature size of a few micron scale has the advantage of low cost and simple process comparing to the semiconductor process, E-beam lithography, ECM and other machining process. Further, the femtosecond laser is the better tool to machine the micro parts due to its characteristics of minimizing the heat affected zone(HAZ). As a result of line cutting of Si, the optimal condition had the region of the effective energy of 2mJ/mm-2.5mJ/mm with the power of 0.5mW-1.5mW. The polarization effects of the incident beam existed in the machining qualities, therefore the sample motion should be perpendicular to the projection of the electric vector. We also observed the periodic ripple patterns which come out in condition of the pulse overlap with the threshold energy. Finally, we could machined the groove with the linewidth of below $2{\mu}m$ for the application of MEMS device repairing, scribing and arbitrary patterning.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2005.06a
• /
• pp.577-580
• /
• 2005

Surface quality of a micro-processed sample with laser has been investigated by using of scanning confocal microscope(SCM) and atomic force microscope(AFM). Samples are bump electrodes and ITO glass of LCD module used in a mobile phone and a wafer surface scribed by UV laser. A image of $140\times120{\mu}m^2$ is obtained within 1 second by SCM because scan speed of a x-axis and y-axis are 1kHz and 1Hz, respectively. AFM is able to measure correctly hight and width of ITO and scribing depth and width of a wafer with a resolution less than 300 . However, the scan speed is slow and it is difficult to distinguish a surface composed of different nm kinds of materials. Results show that SCM is preferable to obtain a image of a sample composed of different kinds of material than AFM because the intensity of a reflected light from surface is different from each material.

• Journal of the Korean Society for Precision Engineering
• /
• v.23 no.4 s.181
• /
• pp.52-59
• /
• 2006

Surface qualities of a micro-processed sample with a pulse laser have been investigated by making use of scanning confocal microscope(SCM) and atomic force microscope(AFM). Samples are bump electrodes and ITO glass of LCD module used in a mobile phone and a wafer surface scribed by UV laser. A image of $140{\times}120{\mu}m^2$ is obtained within 1 second by SCM because scan speed of a x-axis and y-axis are 1kHz and 1Hz, respectively. AFM is able to correctly measure the hight and width of ITO, and scribing depth and width of a wafer with a resolution less than 300nm. However, the scan speed is slow and it is difficult to distinguish a surface composed of different kinds of materials. Results show that SCM is preferable to obtain a image of a sample composed of different kinds of material than AFM because the intensity of a reflected light from the surface is different for each material.

• Current Photovoltaic Research
• /
• v.5 no.3
• /
• pp.95-99
• /
• 2017

The interconnecting shingled solar cells method shows extremely high ratio active area per total area and has the excellent potential for high power PV (photovoltaic). Compared to the conventional module, it can have much more active area due to busbar-free structure. The properties of ECA (electrically conductive adhesives) are significant to fabricate the shingled array PV since it should be used in terms of electric and structural connection. Various ECA were tried and characterized to optimize the soldiering conditions. The open circuit voltage of shingled array cells showed a three-fold increase and efficiency was also increased by 1.63%. The shingled array cells used in CE3103WLV showed the highest power and in CA3556HF the lowest curing temperature and very fast curing time.

• Journal of the Institute of Convergence Signal Processing
• /
• v.6 no.4
• /
• pp.212-216
• /
• 2005

In an ultrasonic glass scriber, the effect of ultrasonic vibration and its optimum driving frequency were investigated experimentally. To investigate the optimum ultrasonic frequency theoretically, the vibration model of the ultrasonic scriber is assumed. The frequency for maximum amplitude of acceleration is obtained theoretically. To investigate the depth of cutting edge corresponding the each frequency. The quartz glass plate specimen with a dimension of $200mm(L){\times}30mm(W){\times}3mm(T)$ is selected. The ultrasonic transducer is operated by the constant acceleration amplitude for the every frequency. The maximum crack depth was generated when the driving frequency was 18.35kHz. These results were in good agreement with those of the calculated model theoretically.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.22 no.10
• /
• pp.826-831
• /
• 2009

In this paper, a high power RF amplifier module using AlN substrate of high thermal conductivity has been proposed. This RF amplifier module has the advantage of compact size and effective heat dissipation for the packaging of high power chip. To fabricate the thru-hole and scribing line on AlN substrate, the key parameters of $CO_2$ laser were experimented. And then, microstrip lines and spiral planar inductors were fabricated on an AlN substrate using the thin-film process. The fabricated microstrip lines on the AlN substrate has an attenuation value of 0.1 dB/mm up to 10 GHz. The fabricated spiral planar inductor has a high quality factor, a maximum of about 62 at 1 GHz for a 5.65 nH inductor. Packaging of a RF power amplifier was implemented on an AlN substrate with thru-hole. From the measured results, the gain is 24 dB from 13 to 15 GHz and the output power is 33.65 dBm(2.3 W).