• Journal of the Microelectronics and Packaging Society
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• v.12 no.2 s.35
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• pp.129-134
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• 2005

Electroplating copper is the important role in formation of 3D stacking interconnection in SiP (System in Package). The I-V characteristics curves are investigated at different electrolyte conditions. Inhibitor and accelerator are used simultaneously to investigate the effects of additives. Three different sizes of via are tested. All via were prepared with RIE (reactive ion etching) method. Via's diameter are 50, 75, $100{\mu}m$ and the height is $100{\mu}m$. Inside via, Ta was deposited for diffusion barrier and Cu was deposited fer seed layer using magnetron sputtering method. DC, pulse and pulse revere current are used in this study. With DC, via cannot be filled without defects. Pulse plating can improve the filling patterns however it cannot completely filled copper without defects. Via was filled completely without defects using pulse-reverse electroplating method.

• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2002.05a
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• pp.193-197
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• 2002

The tribological properties and van der Waals attractive forces and the thermal stability of films are very important characteristics of highly hydrophobic fluorocarbon (FC) films for the long-term reliability of nano system. The effect of thermal annealing on films and van der Waals attractive forces and friction coefficient of films have been investigate d in this study. It was coated Al wafer which was treated O2 and Ar that ocatfluorocyclobutane ($C_4_{8}$) and Ar were supplied to the CVD chamber in the ratio of 2:3 for deposition of FC Films. Static contact angle and dynamic contact angle were used to characterize FC films. Thickness of films was measured by variable angle spectroscopy ellipsometer (VASE). Nanotribological data was got by atomic force microscopy (AFM) to measure roughness, lateral force microscopy (LFM) to measure friction force, and force vs. distance (FD) curve to evaluate adhesion force. FC films were cured in N2 and vacuum. The film showed the slight changes in its properties after 3 hr annealing. FTIR ATR studies showed the decrease of C-F peak intensity in the spectra as the annealing time increased. A significant decrease of film thickness has been observed. The friction force of Al surface was at least thirty times higher than ones with FC films. The adhesive force of bare Al was greater than 100 nN. After deposit FC films adhesive force was decreased to 40 nN. The adhesive force of films was decreased down to 10 nN after 24 hr annealing. During 24 hr annealing in $N_2$and vacuum at $100^{\circ}C$ film properties were not changed so much.

• Journal of the Microelectronics and Packaging Society
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• v.9 no.1
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• pp.21-28
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• 2002

Bismuth and Indium added Sn-Cu-Ni solder alloy was investigated for a new lead free solder. The thermal, electrical and mechanical properties were characterized for the Sn-0.7%(Cu+Ni) solder alloy by adding 2~5% Bi and 2~ 10% In. The melting point of solder alloy was in range of 200 to $222^{\circ}C$ and the mushy zone was in range of 20 to $37^{\circ}C$. This alloys could be adapted to middle and high temperature solder materials. A new solder alloy composition. Sn-0.7%(Cu+Ni) -3.5%Bi-2%In is very promising with high performance and effective cost. The melting point was $220^{\circ}C$, the mushy zone range was $25^{\circ}C$, and mechanical, electrical and wetting properties were competitive with those of other lead-free solder except the lower elongation value.

• Journal of the Microelectronics and Packaging Society
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• v.6 no.2
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• pp.75-81
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• 1999

$CaTiO_3$-$ La(Mg_{2/3}Ta_{1/3})O_3$ solid solutions were prepared in order to improve the microwave dielectric properties of $CaTiO_3$. XRD analysis revealed that the crystal structure of the solid solution changed from orthorhombic to monoclinic as the amount of $ La(Mg_{2/3}Ta_{1/3})O_3$increased. When x=0.3 in (1-x)$CaTiO_3+xLa(Mg_{2/3}Ta_{1/3})O_3$, the dielectric constant was 49, the temperature coefficient of resonance frequency was +$14ppm/^{\circ}C$, and $Q \times f_0$ was 17000.

• Journal of the Microelectronics and Packaging Society
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• v.25 no.4
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• pp.137-142
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• 2018

Room temperature ferromagnetism of Co doped ZnO was studied using (ZnO/Co) multilayer structure, and the effects of ZnO sub-layer thickness on the RT ferromagnetism was investigated. As for the as-deposited state, the diamagnetism was observed for ($ZnO\;20{\AA}/Co\;x{\AA}$) while the ferromagnetism was observed for ($ZnO\;40{\AA}/Co\;x{\AA}$). After vacuum-annealed, both showed the RT ferromagnetism and ($ZnO\;40{\AA}/Co\;x{\AA}$) structure interestingly showed negative remanence magnetization behavior. UV-Vis spectrometer revealed that Co atoms were substituted with Zn in ZnO and Co cluster was not found in XPS and HRTEM EDS analysis.

• Journal of the Microelectronics and Packaging Society
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• v.30 no.2
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• pp.43-51
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• 2023

In this paper, we introduce the development trends of power devices which is the key component for power conversion system in electric vehicles, and discuss the characteristics of the next-generation wide-bandgap (WBG) power devices. We provide an overview of the characteristics of the present mainstream Si insulated gate bipolar transistor (IGBT) devices and technology roadmap of Si IGBT by different manufacturers. Next, recent progress and advantages of SiC metal-oxide-semiconductor field-effect transistor (MOSFET) which are the most important unipolar devices, is described compared with conventional Si IGBT. Furthermore, due to the limitations of the current GaN power device technology, the issues encountered in applying the power conversion module for electric vehicles were described.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.46 no.1
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• pp.23-31
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• 2023

Research and interest in sustainable printing are increasing in the packaging printing industry. Currently, predicting the amount of ink required for each work is based on the experience and intuition of field workers. Suppose the amount of ink produced is more than necessary. In this case, the rest of the ink cannot be reused and is discarded, adversely affecting the company's productivity and environment. Nowadays, machine learning models can be used to figure out this problem. This study compares the ink usage prediction machine learning models. A simple linear regression model, Multiple Regression Analysis, cannot reflect the nonlinear relationship between the variables required for packaging printing, so there is a limit to accurately predicting the amount of ink needed. This study has established various prediction models which are based on CART (Classification and Regression Tree), such as Decision Tree, Random Forest, Gradient Boosting Machine, and XGBoost. The accuracy of the models is determined by the K-fold cross-validation. Error metrics such as root mean squared error, mean absolute error, and R-squared are employed to evaluate estimation models' correctness. Among these models, XGBoost model has the highest prediction accuracy and can reduce 2134 (g) of wasted ink for each work. Thus, this study motivates machine learning's potential to help advance productivity and protect the environment.

• Journal of the Microelectronics and Packaging Society
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• v.31 no.3
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• pp.58-61
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• 2024

In a semiconductor system, the operation of sensors plays a crucial role in recognizing information, serving as the starting point for processing external information. This study evaluates the applicability of semiconductor systems by analyzing the operational characteristics of ultraviolet (UV) detection devices using gallium oxide. Gallium oxide exhibits a property where its resistance changes in response to UV light, making it feasible to implement detection devices utilizing this material. However, to determine its applicability in semiconductor systems, detailed studies on its operational characteristics are necessary. In this study, by varying the size of the electrodes, we assessed whether the formation of current paths in gallium oxide in response to UV light is localized. Additionally, we confirmed the response speed to UV light, comparable to commercially available products, through electrical measurements. Through this, we verified the commercial applicability of gallium oxide and its potential integration into various semiconductor systems.

• Resources Recycling
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• v.16 no.1 s.75
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• pp.15-27
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• 2007

The Korean Auto industry has developed remarkably over the past 30 years. In 2005 alone, Korea produced 3.7 million vehicles, and the number of vehicles registered surpassed the 15 million marks. The rapid growth in registration, however, has given increasing problems to the traffic congestion and the environmental pollution. The system for handling of ELV in Korea is governed by the 'Motor management law'. The law places the responsibility for vehicle scrapping directly on the vehicle owners. The take-back rate of ELV reaches nearly 100% in Korea since 1987. To further entourage recycling, the government introduced the extended producer responsibility system(EPRS) starting January 1, 2003, which imposes waste recycling obligations on producers or importers. According to the system, producers must recycle home appliances and packaging materials. This system, however, did not involve the automobiles. In 2006, the automobiles recycling law is under preparing now by the government. This article is concerning current status for End-of-Life vehicle's recycling and the recycling system model for advanced ELV industries in Korea.

• Journal of Biosystems Engineering
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• v.43 no.4
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• pp.379-385
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• 2018

Purpose: Postharvest handling of onions (harvesting, cleaning, grading, cooling, storing, and transport) should be performed continually to reduce costs and improve quality. The purpose of this study is to a) determine the design parameters and operating conditions of anion auto-dumping that constitutes a key component of the postharvest bulk handling machinery system, and b) to perform a performance test with the auto-dump prototype system. Methods: Kinematic analyses and computer simulations of the auto-dump mechanism were applied to analyze the operating conditions and design parameters. Results: The optimum working condition for the auto-dump was determined from kinetic analyses. In addition, the interaction between the velocity of the hydraulic cylinder and the angular velocity of the auto-dump were analyzed in order to control the bulk handling machinery system. The acting forces and optimum operating conditions of the hydraulic cylinder were determined by analyzing the forces related to the mass of inertia of the auto-dump assembly during rotation. The method of controlling the feeding rate of onions in terms of the uniformity of the stacking pattern and the control of the entire system was better than the two-stage method of controlling the rotational speed of the auto-dump. Based on the performance test with the prototype for the auto-dump, the stacking pattern and rigidity of the system were analyzed. Conclusions: These results would be of great importance in the postharvest bulk handling machinery system for onions.