• Journal of the Korean Society for Precision Engineering
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• v.27 no.7
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• pp.28-35
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• 2010

In the display industry, COG bonding method is being applied to production of LCD panels that are used for mobile phones and monitors, and is one of the mounting methods optimized to compete with the trend of ultra small, ultra thin and low cost of display. In COG bonding process, electrical characteristics such as contact resistance, insulation property, etc and mechanical characteristics such as bonding strength, etc depend on properties of conductive particles and epoxy resin along with ACF materials used for COG by manufacturers. As the properties of such materials have close relation to optimization of bonding conditions such as temperature, pressure, time, etc in COG bonding process, it is requested to carry out an in-depth study on characteristics of COG bonding, based on which development of bonding process equipment shall be processed. In this study were analyzed the characteristics of COG bonding process, performed the analysis and reliability evaluation on electrical and mechanical characteristics of COG bonding using ACF to find optimum bonding conditions for ACF, and performed the experiment on bonding characteristics regarding fine pitch to understand the affection on finer pitch in COG bonding. It was found that it is difficult to find optimum conditions because it is more difficult to perform alignment as the pitch becomes finer, but only if alignment has been made, it becomes similar to optimum conditions in general COG bonding regardless of pitch intervals.

• ETRI Journal
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• v.36 no.3
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• pp.343-351
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• 2014

For the fine-pitch application of flip-chip bonding with semiconductor packaging, fluxing and hybrid underfills were developed. A micro-encapsulated catalyst was adopted to control the chemical reaction at room and processing temperatures. From the experiments with a differential scanning calorimetry and viscometer, the chemical reaction and viscosity changes were quantitatively characterized, and the optimum type and amount of micro-encapsulated catalyst were determined to obtain the best pot life from a commercial viewpoint. It is expected that fluxing and hybrid underfills will be applied to fine-pitch flip-chip bonding processes and be highly reliable.

• International Journal of Precision Engineering and Manufacturing
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• v.8 no.1
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• pp.52-58
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• 2007

We propose a new contact detection algorithm for fine pitch wire bonding. Fast and stable contact detection of the z-axis in wire bonding is extremely important to maintain the quality of fine pitch gold wire bonding processes, which use a small pad less than $70{\mu}m$ in diameter. A small perturbation in the contact detection time causes a large difference in the size of the formed squashed ball. The new detection method is based on a statistical approach and designed for a discrete Kalman filter. It is faster and has smaller detection time variations than conventional detection methods. Experimental results are presented to demonstrate the advantages of the proposed algorithm.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.12 no.3
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• pp.36-40
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• 2013

Recently, electronic equipments become smaller, more functional, and more complex than before. As these trends, MLC(multi-layer ceramic) circuit has been emerged to a promising technology in semiconductor inspection industry. Especially, multi-layer ceramic which is consisted of many fine-pitch multi-hole is used to produce a semiconductor inspection unit. The hole is processed by UV laser. But, working conditions are changed all the time. Therefore real time measurement of fine-pitch multi-hole is very important method for ensuring performance. In this paper we found the best method for illuminating and auto focusing. And, we verified our equipment.

• Journal of Sensor Science and Technology
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• v.19 no.2
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• pp.130-136
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• 2010

The microbolometer array sensor with fine pitch pixel array has been implemented to the released amorphous silicon layer supported by two contact pads. For the design of focal plane mirror with geometrical flatness, the simple beam test structures were fabricated and characterized. As the beam length decreased, the effect of beam width on the bending was minimized, Mirror deformation of focal plane in a real pixel showed downward curvature by residual stress of a-Si and Ti layer. The mirror tilting was caused by the mis-align effect of contact pad and confirmed by FEA simulation results. The properties of bolometer have been measured as such that the NETD 145 mK, the TCR -2 %/K, and thermal time constant 1.99 ms.

• 한국정보디스플레이학회:학술대회논문집
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• 2002.08a
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• pp.275-278
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• 2002

Conductive adhesives are commonly used for the interconnections of fine pitch, small packages like mobile applications. Since conductive particles connect mechanically with contact pads to give somewhat higher contact resistance, a metallurgical interconnection, which provides both fine pitch and low resistance, was studied using silver ball and indium which can be made at low temperatures. The connection resistance of the In-Ag metallurgical interconnection was lower than that of the Ni/Au-Ag mechanical interconnection and the former showed little dependency on the bonding load in contrast to the latter.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.423-426
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• 2005

A new chip on glass(COG) technique by making use of a high power diode laser for LCD driver IC packaging of LCD has been developed. A laser joining technology of the connection of IC chip to glass panel has several advantages over conventional method such as hot plate joining: shorter process time, high reliability of joining, and better fur fine pitch joining. The reach time to cure temperature of ACF in laser joining is within 1 second. In this study, results show that the total process time of joining is reduced by halves than that of conventional method. The adhesion strength is mainly 100-250 N/cm. It is confirmed that the COG technology using high power diode laser joining can be applied to advanced LCDs with a fine pitch.

• Proceedings of the KWS Conference
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• 1999.10a
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• pp.239-242
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• 1999

• Journal of Welding and Joining
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• v.27 no.3
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• pp.17-22
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• 2009

• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2007.04a
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• pp.49-65
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• 2007