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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Microelectronics and Packaging Society
Journal Basic Information
Journal DOI :
The Korean Microelectronics and Packaging Society
Editor in Chief :
Volume & Issues
Volume 21, Issue 4 - Dec 2014
Volume 21, Issue 3 - Sep 2014
Volume 21, Issue 2 - Jun 2014
Volume 21, Issue 1 - Mar 2014
Selecting the target year
Power Module Packaging Technology with Extended Reliability for Electric Vehicle Applications
Yoon, Jeong-Won ; Bang, Jung-Hwan ; Ko, Yong-Ho ; Yoo, Se-Hoon ; Kim, Jun-Ki ; Lee, Chang-Woo ;
Journal of the Microelectronics and Packaging Society, volume 21, issue 4, 2014, Pages 1~13
DOI : 10.6117/kmeps.2014.21.4.001
The paper gives an overview of the concepts, basic requirements, and trends regarding packaging technologies of power modules in hybrid (HEV) and electric vehicles (EV). Power electronics is gaining more and more importance in the automotive sector due to the slow but steady progress of introducing partially or even fully electric powered vehicles. The demands for power electronic devices and systems are manifold, and concerns besides aspects such as energy efficiency, cooling and costs especially robustness and lifetime issues. Higher operation temperatures and the current density increase of new IGBT (Insulated Gate Bipolar Transistor) generations make it more and more complicated to meet the quality requirements for power electronic modules. Especially the increasing heat dissipation inside the silicon (Si) leads to maximum operation temperatures of nearly
. As a result new packaging technologies are needed to face the demands of power modules in the future. Wide-band gap (WBG) semiconductors such as silicon carbide (SiC) or gallium nitride (GaN) have the potential to considerably enhance the energy efficiency and to reduce the weight of power electronic systems in EVs due to their improved electrical and thermal properties in comparison to Si based solutions. In this paper, we will introduce various package materials, advanced packaging technologies, heat dissipation and thermal management of advanced power modules with extended reliability for EV applications. In addition, SiC and GaN based WBG power modules will be introduced.
Alternative Sintering Technology of Printed Nanoparticles for Roll-to-Roll Process
Lee, Eun Kyung ; Eun, Kyoungtae ; Ahn, Young Seok ; Kim, Yong Taek ; Chon, Min-Woo ; Choa, Sung-Hoon ;
Journal of the Microelectronics and Packaging Society, volume 21, issue 4, 2014, Pages 15~24
DOI : 10.6117/kmeps.2014.21.4.015
Recently, a variety of printing technologies, including ink jet, gravure, and roll-to-roll (R2R) printing, has generated intensive interest in the application of flexible and wearable electronic devices. However, the actual use of printing technique is much limited because the sintering process of the printed nanoparticle inks remains as a huge practical drawback. In the fabrication of the conductive metal film, a post-sintering process is required to achieve high conductivity of the printed film. The conventional thermal sintering takes considerable sintering times, and requires high temperatures. For application to flexible devices, the sintering temperature should be as low as possible to minimize the damage of polymer substrate. Several alternative sintering methods were suggested, such as laser, halogen lamp, infrared, plasma, ohmic, microwave, and etc. Eventually, the new sintering technique should be applicable to large area, R2R, and polymer substrate as well as low cost. This article reviews progress in recent technologies for several sintering methods. The advantages and disadvantages of each technology will be reviewed. Several issues for the application in R2R process are discussed.
NIR Fluorescence Imaging Systems with Optical Packaging Technology
Yang, Andrew Wootae ; Cho, Sang Uk ; Jeong, Myung Yung ; Choi, Hak Soo ;
Journal of the Microelectronics and Packaging Society, volume 21, issue 4, 2014, Pages 25~31
DOI : 10.6117/kmeps.2014.21.4.025
Bioimaging has advanced the field of nanomedicine, drug delivery, and tissue engineering by directly visualizing the dynamic mechanism of diagnostic agents or therapeutic drugs in the body. In particular, wide-field, planar, near-infrared (NIR) fluorescence imaging has the potential to revolutionize human surgery by providing real-time image guidance to surgeons for target tissues to be resected and vital tissues to be preserved. In this review, we introduce the principles of NIR fluorescence imaging and analyze currently available NIR fluorescence imaging systems with special focus on optical source and packaging. We also introduce the evolution of the FLARE intraoperative imaging technology as an example for image-guided surgery.
Four Point Bending Test for Adhesion Testing of Packaging Strictures: A Review
Mahan, Kenny ; Han, Bongtae ;
Journal of the Microelectronics and Packaging Society, volume 21, issue 4, 2014, Pages 33~39
DOI : 10.6117/kmeps.2014.21.4.033
To establish the reliability of a packaging structures, adhesion testing of key interfaces is a critical task. Due to the material mismatch, the interface may be prone to delamination failure due to conditions during the manufacturing of the product or just from the day-to-day use. To assess the reliability of the interface adhesion strength testing can be performed during the design phase of the product. One test method of interest is the four-point bending (4PB) adhesion strength test method. This test method has been implemented in a variety of situations to evaluate the adhesion strength of interfaces in bimaterial structures to the interfaces within thin film multilayer stacks. This article presents a review of the 4PB adhesion strength testing method and key implementations of the technique in regards to semiconductor packaging.
The activation Energy of the Niobium donor in n-type TiO
film grown by Pulsed Laser Deposition
Bae, Hyojung ; Ha, Jun-Seok ; Park, Seung Hwan ;
Journal of the Microelectronics and Packaging Society, volume 21, issue 4, 2014, Pages 41~44
DOI : 10.6117/kmeps.2014.21.4.041
In this paper, we will investigate the activation energies of Nb for
using Hall effect measurement and photoluminescence (PL) system. Nb-doped
thin film was grown on
substrate by pulsed laser deposition (PLD) technique. After measurements, activation energies of niobium donor were 14.52 meV in Hall effect measurement, and 6.72 meV in PL measurement, respectively. These results showed different tendencies which are measured from the samples with acceptor materials. Therefore, it is thought that more research on activation energies for dopants of shallow donor level is expected.
Growth of Non-Polar a-plane ZnO Layer On R-plane (1-102) Sapphire Substrate by Hydrothermal Synthesis
Jang, Jooil ; Oh, Tae-Seong ; Ha, Jun-Seok ;
Journal of the Microelectronics and Packaging Society, volume 21, issue 4, 2014, Pages 45~49
DOI : 10.6117/kmeps.2014.21.4.045
In this study, we grew non-polar ZnO nanostructure on (1-102) R-plane sapphire substrates. As for growth method of ZnO, we used hydrothermal synthesis which is known to have the advantages of low cost and easy process. For growth of non-polar, the deposited AZO seed buffer layer with of 80 nm on R-plane sapphire by radio frequency magnetron sputter was annealed by RTA(rapid thermal annealing) in the argon atmosphere. After that, we grew ZnO nanostructure on AZO seed layer by the added hexamethylenetramine (HMT) solution and sodium citrate at
. With two types of additives into solution, we investigated the structures and shapes of ZnO nanorods. Also, we investigate the possibility of formation of 2D non-polar ZnO layer by changing the ratio of two additives. As a result, we could get the non-polar A-plane ZnO layer with well optimized additives' concentrations.
Electrical Resistivity and Thermal Conductivity of Paste Containing Ag-coated Cu Flake Filler
Kim, Gahae ; Jung, Kwang-Mo ; Moon, Jong-Tae ; Lee, Jong-Hyun ;
Journal of the Microelectronics and Packaging Society, volume 21, issue 4, 2014, Pages 51~56
DOI : 10.6117/kmeps.2014.21.4.051
After the preparation of low-cost conductive paste containing Ag-coated Cu flakes, thermal conductivity and electrical resistivity of the paste were measured with different curing conditions. Under air-curing conditions, the thermal conductivity of the cured sample increased with an increase of curing time from 30 to 60 min. After identical curing time of 60 min, the sample cured under nitrogen indicated more enhanced thermal conductivity than that cured under air, approaching that of paste containing pure Ag flakes. Under air-curing conditions, meanwhile, the electrical resistivity of the cured sample increased with an increase of curing time from 30 to 60 min. After identical curing time of 60 min, however, the sample cured under nitrogen indicated extremely enhanced electrical resistivity (
) in comparison with that cured under air.
The Improvement of Electrical Characteristics of Inkjet-printed Cu films with Stress Relaxation during Thermal Treatment
Yi, Seol-Min ; Joo, Young-Chang ;
Journal of the Microelectronics and Packaging Society, volume 21, issue 4, 2014, Pages 57~62
DOI : 10.6117/kmeps.2014.21.4.057
Using flexible bismaleimide-triazine co-polymer as a substrate, inkjet-printed Cu films were also investigated for low-cost and process feasibility of flexible electronics. After annealing at
for 1 h under various reducing ambient, surface color was changed to red and electrical resistivity was decreased to the level of conductor under formic acid ambient. However, its resistivity was much higher than conventional copper films due to surface crack. In order to reduce the residual film stress after annealing, additional isothermal treatment was inserted before anneal hiring the stress relaxation applied in processes of amorphous materials. As a result, no surface crack was observed and electrical resistivity of
was measured after annealing at
with stress relaxation while electrical resistivity of
was observed after normal annealing without relaxation. The effect of stress relaxation was also confirmed by observing surface crack after decreasing the relaxation time to 0 min.
An investigation on dicing 28-nm node Cu/low-k wafer with a Picosecond Pulse Laser
Hsu, Hsiang-Chen ; Chu, Li-Ming ; Liu, Baojun ; Fu, Chih-Chiang ;
Journal of the Microelectronics and Packaging Society, volume 21, issue 4, 2014, Pages 63~68
DOI : 10.6117/kmeps.2014.21.4.063
For a nanoscale Cu/low-k wafer, inter-layer dielectric (ILD) and metal layers peelings, cracks, chipping, and delamination are the most common dicing defects by traditional diamond blade saw process. Sidewall void in sawing street is one of the key factors to bring about cracks and chipping. The aim of this research is to evaluate laser grooving & mechanical sawing parameters to eliminate sidewall void and avoid top-side chipping as well as peeling. An ultra-fast pico-second (ps) laser is applied to groove/singulate the 28-nanometer node wafer with Cu/low-k dielectric. A series of comprehensive parametric study on the recipes of input laser power, repetition rate, grooving speed, defocus amount and street index has been conducted to improve the quality of dicing process. The effects of the laser kerf geometry, grooving edge quality and defects are evaluated by using scanning electron microscopy (SEM) and focused ion beam (FIB). Experimental results have shown that the laser grooving technique is capable to improve the quality and yield issues on Cu/low-k wafer dicing process.
Flexible Durability of Ultra-Thin FPCB
Jung, Hoon-Sun ; Eun, Kyoungtae ; Lee, Eun-Kyung ; Jung, Ki-Young ; Choi, Sung-Hoon ; Choa, Sung-Hoon ;
Journal of the Microelectronics and Packaging Society, volume 21, issue 4, 2014, Pages 69~76
DOI : 10.6117/kmeps.2014.21.4.069
In this study, we developed an ultra-thin flexible printed circuit board(FPCB) using the sputtered flexible copper clad laminate. In order to enhance the adhesion between copper and polyimide substrate, a NiMoNb addition layer was applied. The mechanical durability and flexibility of the ultra-thin FPCB were characterized by stretching, twisting, bending fatigue test, and peel test. The stretching test reveals that the ultra-thin FPCB can be stretched up to 7% without failure. The twisting test shows that the ultra-thin FPCB can withstand an angle of up to
. In addition, the bending fatigue test shows that the FPCB can withstand 10,000 bending cycles. Numerical analysis of the stress and strain during stretching indicates the strain and the maximum von Mises stress of the ultra-thin FPCB are comparable to those of the conventional FPCB. Even though the ultra-thin FPCB shows slightly lower durability than the conventional FPCB, the ultra-thin FPCB has enough durability and robustness to apply in industry.
The Effect of Graphene on the Electrical Properties of a Stretchable Carbon Electrode
Lee, T.W. ; Park, H.H. ;
Journal of the Microelectronics and Packaging Society, volume 21, issue 4, 2014, Pages 77~82
DOI : 10.6117/kmeps.2014.21.4.077
Stretchable electrodes are focused due to many demands for soft electronics. One of the candidates, carbon black composites have advantages of low cost, easy processing and decreasing resistivity in a certain range during stretching. However, the electrical conductivity of carbon black composites is not enough for electronic devices. Graphene is 2-dimensional nanostructured carbon based material which shows good electrical properties and flexibility. They may help to improve electrical conductivity of the carbon black composites. In this study, graphene was added to a carbon black electrode to enhance electrical properties and investigated. Electrical resistivity of graphene added carbon electrode decreased comparing with that of carbon black electrode because graphene bridged non-contacting carbon black aggregates to strengthen the conductive network. Also graphene reduced an increase in the resistance of the carbon black electrode applied to strain because they connected gap of separated carbon black aggregates and aligned along the stretching direction at the same time. In conclusion, an addition of graphene to carbon black gives two benefits on the electrical properties of carbon black composite as a stretchable electrode.
Printing Morphology and Rheological Characteristics of Lead-Free Sn-3Ag-0.5Cu (SAC) Solder Pastes
Sharma, Ashutosh ; Mallik, Sabuj ; Ekere, Nduka N. ; Jung, Jae-Pil ;
Journal of the Microelectronics and Packaging Society, volume 21, issue 4, 2014, Pages 83~89
DOI : 10.6117/kmeps.2014.21.4.083
Solder paste plays a crucial role as the widely used joining material in surface mount technology (SMT). The understanding of its behaviour and properties is essential to ensure the proper functioning of the electronic assemblies. The composition of the solder paste is known to be directly related to its rheological behaviour. This paper provides a brief overview of the solder paste behaviour of four different solder paste formulations, stencil printing processes, and techniques to characterize solder paste behaviour adequately. The solder pastes are based on the Sn-3.0Ag-0.5Cu alloy, are different in their particle size, metal content and flux system. The solder pastes are characterized in terms of solder particle size and shape as well as the rheological characterizations such as oscillatory sweep tests, viscosity, and creep recovery behaviour of pastes.
Cu-Filling Behavior in TSV with Positions in Wafer Level
Lee, Soon-Jae ; Jang, Young-Joo ; Lee, Jun-Hyeong ; Jung, Jae-Pil ;
Journal of the Microelectronics and Packaging Society, volume 21, issue 4, 2014, Pages 91~96
DOI : 10.6117/kmeps.2014.21.4.091
Through silicon via (TSV) technology is to form a via hole in a silicon chip, and to stack the chips vertically for three-dimensional (3D) electronics packaging technology. This can reduce current path, power consumption and response time. In this study, Cu-filling substrate size was changed from Si-chip to a 4" wafer to investigate the behavior of Cu filling in wafer level. The electrolyte for Cu filling consisted of
and small amount of additives. The anode was Pt, and cathode was changed from
to 4" wafer. As experimental results, in the case of
Si chip, suitable distance of electrodes was 4cm having 100% filling ratio. The distance of 0~0.5 cm from current supplying location showed 100% filling ratio, and distance of 4.5~5 cm showed 95%. It was confirmed good TSV filling was achieved by plating for 2.5 hrs.
Effect of Aging treatment and Epoxy on Bonding Strength of Sn-58Bi solder and OSP-finished PCB
Kim, Jungsoo ; Myung, Woo-Ram ; Jung, Seung-Boo ;
Journal of the Microelectronics and Packaging Society, volume 21, issue 4, 2014, Pages 97~103
DOI : 10.6117/kmeps.2014.21.4.097
Among various lead-free solders, the Sn-58Bi solders have been considered as a highly promising lead-free solders because of its low melting temperature and high tensile strength. However, Sn-58Bi solder has the poor ductility. To enhance the mechanical property of Sn-58Bi solder, epoxy-enhanced Sn-58Bi solders have been studied. This study compared the microstructures and the mechanical properties of Sn-58Bi solder and Sn-58Bi epoxy solder with aging treatment. The solders ball were formed on the printed circuit board (PCB) with organic solderability preservative (OSP) surface finish, and then the joints were aged at 85, 95, 105 and
for up to 100, 300, 500 and 1000 hours. The shear test was conducted to evaluate the mechanical property of the solder joints.
intermetallic compound (IMC) layer grew with increasing aging time and temperature. The IMC layer for the Sn-58Bi epoxy solder was thicker than that for the Sn-58Bi solder. According to result of shear test, the shear strength of Sn-58Bi epoxy solder was higher than that of Sn-58Bi solder and the shear strength decreased with increasing aging time.
Effects of Organic Passivation Films on Properties of Polymer Solar Cells with P3HT:PC
BM Active Layers
Lee, Sang Hee ; Park, Byung Min ; Cho, Yang Keun ; Chang, Ho Jung ; Jung, Jae Jin ; Pyee, Jaeho ;
Journal of the Microelectronics and Packaging Society, volume 21, issue 4, 2014, Pages 105~110
DOI : 10.6117/kmeps.2014.21.4.105
It is required to improve the efficiency and the reliability of the polymer solar cells (PSCs) as the energy saving optical device for the future application of the smart farm facilities. In this study, we fabricated the bulk hetero junction PSCs with organic passivation film layer for the reliability improvement of the devices. The effects of the passivation layer on the electrical properties of the PSCs were studied. The materials of passivation layer are composed of poly vinyl alcohol (PVA) and ammonium dichromate, and the passivation films were fabricated by the spin coating method on the P3HT:
/LiF/Al substrate. The prepared structure of the device is the glass/ITO/PEDOT:PSS/P3HT:
/LiF/Al/passivation layer. The performances of the PSCs with the organic passivation film showed better electrical properties compared with the PSCs without passivation layers. The power conversion efficiency (PCE) values of passivated PSCs decreased from 3.0 to 1.3% after air exposure for 140 hrs. In contrast, the PCE values for the devices without passivation decreased sharply from 3.5 to 0.1% under the same exposure condition.
Effect of Dynamic Electric Fields on Dielectric Reliability in Cu Damascene Interconnects
Yeon, Han-Wool ; Song, Jun-Young ; Lim, Seung-Min ; Bae, Jang-Yong ; Hwang, Yuchul ; Joo, Young-Chang ;
Journal of the Microelectronics and Packaging Society, volume 21, issue 4, 2014, Pages 111~115
DOI : 10.6117/kmeps.2014.21.4.111
Effect of dynamic electric fields on dielectric breakdown behavior in Cu damascene interconnects was investigated. Among the DC, unipolar, and bipolar pulse conditions, the longest dielectric lifetime is observed under the bipolar condition because backward Cu ion drift occurs when the direction of electric field is changed by 180 degrees and Cu contamination is prohibited as a results. Under the unipolar pulse condition, the dielectric lifetime increases as pulse frequency increases and it exceed the lifetime under DC condition. It suggests that the intrinsic breakdown of dielectrics significantly affect the dielectric breakdown in addition to Cu contamination. As the unipolar pulse width decreases, dielectric bond breakdown is more difficult to occur.
Cu Through-Via Formation using Open Via-hole Filling with Electrodeposition
Kim, Jae-Hwan ; Park, Dae-Woong ; Kim, Min-Young ; Oh, Tae Sung ;
Journal of the Microelectronics and Packaging Society, volume 21, issue 4, 2014, Pages 117~123
DOI : 10.6117/kmeps.2014.21.4.117
Cu through-vias, which can be used as thermal vias or vertical interconnects, were formed using bottom-up electrodeposition filling as well as top-down electrodeposition filling into open via-holes and their microstructures were observed. Solid Cu through-vias without voids could be successfully formed by bottom-up filling as well as top-down filling with direct-current electrodeposition. While chemical-mechanical polishing (CMP) to remove the overplated Cu layer was needed on both top and bottom surfaces of the specimen processed by top-down filling method, the bottomup process has an advantage that such CMP was necessary only on the top surface of the sample.
Variation of Elastic Stiffness of Polydimethylsiloxane (PDMS) Stretchable Substrates for Wearable Packaging Applications
Choi, Jung-Yeol ; Park, Dae-Woong ; Oh, Tae Sung ;
Journal of the Microelectronics and Packaging Society, volume 21, issue 4, 2014, Pages 125~131
DOI : 10.6117/kmeps.2014.21.4.125
In order to develop stretchable substrates for wearable packaging applications, the variation behavior of elastic modulus was evaluated for transparent PDMS Sylgard 184 and black PDMS Sylgard 170 as a function of the base/curing agent mixing ratio. Both for Sylgard 184 and Sylgard 170, the true elastic modulus evaluated on a true stress-true strain curve was higher more than two times compared to the engineering elastic modulus obtained from an engineering stres-sengineering strain curve, and their difference became larger with increasing the stiffness of the PDMS. Sylgard 184 exhibited a maximum engineering elastic modulus of 1.74 MPa and a maximum true elastic modulus of 3.57 MPa at the base/curing agent mixing ratio of 10. A maximum engineering elastic modulus of 1.51 MPa and a maximum true elastic modulus of 3.64 MPa were obtained for Sylgard 170 at the base/curing agent mixing ratio of 2.
Fabrication of Cu Flakes by Ball Milling of Sub-micrometer Spherical Cu Particles
Kim, Ji Hwan ; Lee, Jong-Hyun ;
Journal of the Microelectronics and Packaging Society, volume 21, issue 4, 2014, Pages 133~137
DOI : 10.6117/kmeps.2014.21.4.133
As a preceding process for preparing several micrometer sized Ag-coated Cu flakes, ball milling of submicrometer-sized Cu particles synthesized through a wet chemical method was performed in order to convert the particles into flakes. To suppress oxidation and aggregation of the particles during ball milling, ethylene glycol and ethyl acetate were used as a medium and a surface modifying agent, respectively. Results obtained with different rotation speeds of a jar indicated that the rotation speed changes a rotating mode, and strikingly alters the final shapes and shape uniformity of Cu particles after milling. The diameter of zirconia ball was also confirmed. Although there was aggregates in the initial submicrometer-sized Cu particles, therefore, well-dispersed Cu flakes with a size of several micrometers were successfully prepared by ball milling through optimization of rotation speed, amount of ethyl acetate, and diameter of zirconia ball.