• Journal of the Semiconductor & Display Technology
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• v.11 no.3
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• pp.39-44
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• 2012

Electronics in modern lives have become more miniaturized and precise. Multi Layered Ceramic Capacitor (MLCC) occupies 50% of electronic components consisting of electronics. This high volume of the production needs high speed and more precise machine performances. The dominate parts of the production equipments are the module transporting components and the visual inspection module. Most visual inspection has been off-line because of the image processing time. In this paper, a new image processing method is proposed to reduce thousands of matrix calculation for image processing and realize on-line high speed inspection.

• Journal of Welding and Joining
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• v.24 no.6
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• pp.21-27
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• 2006

This study was focused on the evaluation of the thermo-mechanical board-level reliability of Pb-bearing and Pb-free surface mount assemblies. The composition of Pb-bearing solder was a typical Sn-37Pb and that of Pb-free solder used in this study was a representative Sn-3.0Ag-0.5Cu in mass %. Thermal shock test was chosen for the reliability evaluation of the solder joints. Typical $Cu_6Sn_5$ intermetallic compound (IMC) layer was formed between both solders and Cu lead frame at the as-reflowed state, while a layer of $Cu_3Sn$ was additionally formed between the $Cu_6Sn_5$ and Cu lead frame during the thermal shock testing. Thickness of the IMC layers increased with increasing thermal shock cycles, and this is very similar result with that of isothermal aging study of solder joints. Shear test of the multi layer ceramic capacitor(MLCC) joints was also performed to investigate the degradation of mechanical bonding strength of solder joints during the thermal shock testing. Failure mode of the joints after shear testing revealed that the degradation was mainly due to the excessive growth of the IMC layers during the thermal shock testing.

• Journal of the Microelectronics and Packaging Society
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• v.25 no.1
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• pp.23-28
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• 2018

Under the 4th Industrial Revolution, implementation of Smart Factory in the field of surface mounting is an emerging issue. In the field of surface mounting, many researches are going on in line with these changes. Among them, we analyzed the method of optimizing the solder printing process which is a core process and the influence of the external factors affecting the printing efficiency. In this analysis, the Big Data provided by the SPI Machine was used to approach the statistical method, and the possibility of predicting the result through simulation with reliable results was confirmed. I hope this study contributes a little to the Smart Factory implementation.

• Proceedings of the KSME Conference
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• 2000.04a
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• pp.873-878
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• 2000

Semiconductor packaging technology is changed rapidly according to the trends of the micro miniaturization of multimedia and information equipment. For I/O limitation and fine pitch limitation, DIP and SOP/QFP are replaced by BGA/CSP. This is one of the surface mount technology(SMT). Solder ball is bumped n the die pad and connected onto mounting board. In ball bump formation, vacuum suction type ball alignment process is widely used, However this type has some problems such as ionization, static electricity and difficulty of fifo(first-input first-out) of solder balls. Seesaw type is reducing these problems and has a structural simplicity and economic efficiency. Ball cartridge velocity and ball aligned plate angle are Important variables to improve the ball alignment Process. In this paper, seesaw-type CSP solder ball loader is developed and the optimal velocity and plate angle are proposed.

• Journal of the Korean Society for Precision Engineering
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• v.26 no.7
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• pp.112-119
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• 2009

The purpose of this study is to evaluate the evaluation of process yield performed by using Sn & Cu treatment on the surface to optimize process condition for Lead-free solder application. The materials which are used for the New Surface Treatment study are Semi-Dulling plating for high speed Sn/Cu alloy of Soft Alloy GTC-33 Pb free known as "UEMURA Method" and plating substrate is alloy 42.Especially in lead-free plating process, it is important to control plating thickness and Copper composition than Sn/Pb plating. Evaluated and controlled plating thickness $12{\pm}3um$, Copper composition $2{\pm}1%$, plating particle and visual inspection. The optimization of these parameters and condition makes it makes possible to apply Sn/Cu Lead-free solder from Sn/Pb alloy.

• Journal of the Korean Society of Systems Engineering
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• v.16 no.1
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• pp.25-35
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• 2020

The South Korean Navy is making efforts to acquire vessels that the new technology of the 4th industry is applied, and as a part of these efforts, it has a plan to mount and operate an Unmanned Surface Vehicle(USV) on a vessel that will be introduced later. However, the recent studies have focused on only development of common platforms and mission equipment for the USV, and have not sufficiently analyzed studies and operatinoal requirements on mother ship that will operate the mounted USV. Hence, this study analyzed and presented requirements of mother ship with the mounted USV in order to operate effectively it when the future medium and large vessels to be acquired by the South Korean Navy intent to operate the USV.

• Journal of Welding and Joining
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• v.27 no.1
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• pp.85-89
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• 2009

Reflow process conditions were investigated for 0402 electric parts with Sn-3.0Ag-0.5Cu solders. Circle hole shape metal mask with 100 m thickness showed excellent printability. Self alignment abilities were 71% for 1005 chips, 52% for 0603 chips, and 3% for 0402 chips. Average joining strengos were 1990 gf for 1005 chips, 867 gf for 0603 chips, and 525 gf for 0402 chips. As mis-mounting angle increased, joining strength decreased. Considering self-alignment ability, mounting angle had to be under $5^{\circ}$ and contact area of the chips had to be over 40% for Pb-free soldering process for 0402 chips.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.23 no.6
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• pp.590-595
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• 2014

We have investigated anamorphic prism lenses with distortions of 0.3-0.5%. We designed the plastic triangular lens and confirmed the minimum resolution using MTF graphs. Also we confirmed that the SVGA optical system can realize a resolution of $864{\times}648$ 56 megapixels. A distortion of about 0.5% aberration appears in the maximum field, and a finite beam aberration of about $15{\mu}m$ is confirmed. We made a mold based on the design data and completed the prism lens through exodus molding. We confirmed the shape error (< $30{\mu}m$) and surface roughness (> 40 nm) of the three sides. We made the video-information-display prototype glasses using prism lens by measuring the performance, we determined the distortion aberration (0.3%) and SVGA resolution. Our approach will enable fabrication of a portable large-screen display device for glasses and sunglasses for the domestic market and, after 2015, for the world market.

• Journal of Mechanical Science and Technology
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• v.16 no.12
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• pp.1664-1672
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• 2002

Gantry mechanisms have been widely used for precision manufacturing and material handling in electronics, nuclear, and automotive industries. Dual-drive servo mechanism is a way to increase control bandwidth, in which two primary axes aligned in parallel are synchronously driven by identical servo motors. With this mechanism, a flexible coupling (compliance mechanism) is often introduced in order to avoid the damage by the servo mismatch between the primary drives located at each side of gantry. This paper describes the design guidelines of the dual-drive servo mechanism with focus on its dynamic characteristics and control ramifications. That is, the effect on the system bandwidth which is critical on the system performance, the errors and torques exerted on guide ways in case of servo mismatch, the vibration characteristics concerned with dynamic error and settling time, and the driving force required at each axis for control are thoroughly investigated.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.16 no.11 s.116
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• pp.1165-1171
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• 2006

This paper presents a new type of jetting dispenser for the integrated circuit (IC) fabrication and surface mount technology The proposed system is featured by the piezoelectric actuator and hydraulic magnification device. After describing structural component of the dispensing mechanism and its operation principle, both the fluid modeling and the hydraulic magnification modeling are undertaken with a lumped-parameter method based on the analogy of the fluid system and mechanical system. A mathematical governing equation is then derived by integrating the fluid model with the mechanical model of the driving piston and piezoelectric actuator. Subsequently, in order to achieve a desired dispensing amount, control algorithm adjusting duty cycle of the driving voltage is synthesized and control responses are presented in time domain.