Jae Pil Jung

University of Seoul, Sŏul, Seoul, South Korea

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Publications (29)37.68 Total impact

  • Taehan-Kŭmsok-Hakhoe-chi = Journal of the Korean Institute of Metals and Materials 06/2014; 52(6):459-465. · 1.02 Impact Factor
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    ABSTRACT: The electrical characteristics and failure of a Through-Silicon Via (TSV) were investigated using a thermal shock test. The electrical characteristics, such as resistance (R), self-inductance (L s ), self-capacitance (C s ), and mutual capacitance (C m ), were extracted using a T-equivalent circuit. A cross section of the Cu-filled via was observed by field emission-scanning electron microscopy and the electrical characteristics were measured using a commercial Agilent E4980A LCR Meter. The experimental results revealed R, L s , C s , and C m values of 3.2 mΩ, 29.3 pH, 12 fF, and 0.42 pF, respectively. C m occurred between the charge-holding TSVs, which changed from 0.42 pF to 0.26 pF due to a permittivity transition of the Cu ion drift. After 1,000 cycles of a thermal shock test, cracks were observed between the opening and around the side of the TSV and Si wafer due to mismatch of the coefficient of thermal expansion between the Cu-plug and Si substrate.
    Electronic Materials Letters 05/2014; 10(3):649-653. · 3.98 Impact Factor
  • Myong-Hoon Roh, Jae Pil Jung, Wonjoong Kim
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    ABSTRACT: In order to investigate the microstructure and mechanical properties of small sized Sn–Bi bump, the eutectic Sn–Bi bumps with a diameter of 25 μm and a height of less than 20 μm after reflow were fabricated by electroplating and reflow. The reflow temperature of the Sn–Bi bumps was 170 °C, and the reflow times were varied from 5 to 20 min. The experimental results showed that a eutectic Sn–Bi composition was obtained by plating at a current density of 30 mA/cm2 for 15 min. The average height and diameter of the bumps reflowed for 5 min were 16.1 ± 0.7 μm and 25.2 ± 0.7 μm, respectively. The microstructure of the reflowed bumps consisted of Sn- and Bi-rich phases. The thickness of the IMC of Cu6Sn5 increased from 1.17 to 2.25 μm with increasing reflow time from 5 to 20 min. The shear strength of the reflowed Sn–Bi bump increased with increasing reflow time, and reached approximately 11 gf at 15 and 20 min. The elastic modulus and hardness of eutectic Sn–Bi bump by nanoindentation were 53.5 and 0.43 GPa. Those of Cu6Sn5 were found to be 121.1 and 6.67 GPa.
    Microelectronics Reliability 01/2014; 54(1):265–271. · 1.21 Impact Factor
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    ABSTRACT: The electrical characteristics and thermal shock properties of a Through Silicon Via (TSV) for the three dimensional (3D) stacking of a Si wafer were investigated. The TSVs were fabricated on a Si wafer by a laser drilling process. The via had a diameter of 75 µm at the via opening and a depth of 150 µm. A daisy chain was made for testing electrical characteristics, such as R sh (sheet resistance), R c (contact resistance) and Z 0 (characteristic impedance). After Cu filling, a cross section of the via was observed by Field Emission-Scanning Electron Microscopy. The electrical characteristics were measured using a commercial impedance analyzer and probe station, which revealed the values of R sh , R c and Z 0 as 35.5 mΩ/sq, 25.4 mΩ and 48.5 Ω, respectively. After a thermal shock test of 500 cycles, no cracks were observed between the TSV and Si wafer. This study confirms that the laser drilling process is an effective method for via formation on a Si wafer for 3D integration technology.
    Electronic Materials Letters 07/2013; 9(4). · 3.98 Impact Factor
  • Myong-Hoon Roh, Jae Pil Jung, Wonjoong Kim
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    ABSTRACT: In this paper, the characteristics of eutectic Sn-Bi microsolder bumps fabricated by electroplating are investigated. The underbump metallization (UBM) layers on a Si chip consist of Al, Cu, Ni, and Au, sequentially from bottom to top. The desired Sn-Bi bump size has a diameter of 22 μm and pitch of 44 μm. In order to obtain the optimal conditions for the eutectic Sn-Bi solder bumps, the polarization curves of Sn, Bi, and Sn-Bi electrolytes are analyzed, and the variation of the Sn- Bi composition as a function of the current density is measured. Experimentally, from the polarization curve, Bi and Sn start to deposit below -0.12 and -0.54 V, respectively, and Sn-Bi codeposition occurs below an electropotential of -0.54 V. The Bi content of the electroplated bumps decreases from 92.4 to 38.2 wt% when the current density is increased from 20 to 50 mA/cm2, and near-eutectic composition of the Sn-61 wt% Bi bump is obtained by plating at 40 mA/cm2 for 5 min. The surface of the Sn-Bi microsolder bumps show plate-like structures with acicular shapes, and the grain size increases with increasing current density. An intermetallic compound layer, estimated as AuSn4 with a thickness of about 0.5 μm, was observed between the UBM layers and the as-plated Sn-Bi bumps.
    IEEE Transactions on Components, Packaging, and Manufacturing Technology 04/2013; 3(4):566-573. · 1.24 Impact Factor
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    ABSTRACT: The electroplating of Sn-3.5 wt% Ag bumps without a photoresist (PR) mould on a Si chip was performed to reduce the production steps and cost for 3-D chip stacking. The electroplating characteristics of Sn-Ag and Sn-Ag bump growth were examined. The Sn-Ag bumps were electroplated on the Cu-plugged TSVs (through-silicon vias) of a Si chip. The Cu plug in the via was produced using a high-speed Cu filling process by a periodic pulse reverse current waveform. The electroplating current was supplied to the exposed Cu surface in the TSVs to produce the Sn-3.5Ag bumps. As the experimental results show, the Sn-3.5Ag bumps were fabricated successfully without a PR mould, with no serious defects by electroplating. The Ag contents in the Sn-Ag bump decreased with increasing current density. Besides, the bump height and width increased with increasing plating time. The bump width grew isotropically because of the absence of a PR mould. The Sn-3.55 wt% Ag bumps were obtained at a current density of -55 mA/cm2 for 20 min on the Cu plugs.
    IEEE Transactions on Components, Packaging, and Manufacturing Technology 04/2013; 3(4):574-580. · 1.24 Impact Factor
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    ABSTRACT: The effect of Ni addition on high speed Cu filling into a TSV (through-silicon-via) was investigated for three dimensional (3D) Si chip stacking. Tapered vias were prepared in a Si wafer by deep reactive ion etching process. In order to increase the filling ratio of Cu-Ni into the via, a periodic pulse reverse (PPR) current waveform was applied for electroplating. For comparison Cu filling in the via was also carried out using a PPR current waveform. The Cu and Cu-Ni alloy-filled via was observed by field emission scanning electron microscopy (FE-SEM) to investigate the filling ratio of the vias and to observe the deposition characteristics. The calculated rate of Cu-Ni nuclei formation on the cathode surface was increased by about 1.7 times by Ni addition compared to Cu filling and the increased nucleation rate of the Cu-Ni alloy over Cu was confirmed by FE-SEM. The filling ratio of the Cu-Ni alloy was 1.3 times higher than that of Cu at the same time. The Cu-Ni filling process by the PPR current waveform was confirmed to be effective to fill the TSV in a short time.
    Metals and Materials International 01/2013; 19(1). · 1.22 Impact Factor
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    ABSTRACT: Brazing technology has been widely used among bonding technologies because it enables to bond various metals, even ceramics, dissimilar metals, and give higher bonding strength, cost down, automation, etc. However, there are many parameters to achieve optimal brazing joint such as brazing alloys, brazing atmospheres, designs and brazing methods, etc. The brazing parameters affect seriously on the characteristic of final brazing products. Stainless steel is broadly used in high temperature applications, chemical industry, heat exchangers, muffler of vehicles, and so on. Accordingly, in this article, brazing alloys, forms of brazing alloys, brazing methods and atmospheres for stainless steel were described.
    Journal of the Korean Welding and Joining Society. 12/2012; 30(6).
  • Santosh Kumar, Jae Yong Park, Jae Pil Jung
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    ABSTRACT: A high speed shear test for Sn-Ag-Cu(3.0 wt %Sn and 0.5 wt % Ag) solder has been studied by varying shearing rate, tip height and solder volume. Failure mode analysis of the solder joint revealed that ductile and brittle failure modes coexist when the shearingspeed is 500 mm/s or higher. The higher the shearing rate, the fewer the ductile failures and the more brittle or mixed failures have been observed. Tip height variation does not have astrong impact on failure mode, but occasions for pad lift appeared to be strongly related with tip height conditions. While the maximum shear force does not provide any indication of the failure mechanism, careful analysis of the force-displacement curves showed the potential of area related indices as a method to analyze the various failure modes.
    Electronic Materials Letters 12/2012; 7(4). · 3.98 Impact Factor
  • Jiheon Jun, Jun Kyu Park, Jae Pil Jung
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    ABSTRACT: A new process of electroplate Sn-Ag bumping without a patterned photo resist (PR) mould on a Si chip for 3-dimensional packaging was investigated. The electroplating characteristics of the Sn-Ag electrolyte and the bump growth were examined. The substrate was a Si die with a thickness of 70 μm in which the through-Si-vias (TSVs) were plugged with Cu. The Sn-Ag bumps were electroplated on the Cu-plugged vias of the Si-chip with an increasing DC current density and plating time. The experimental results of the polarization curve showed that Sn-Ag had two reduction potentials, namely, a Ag reduction starting potential of −0.387 V and a Sn and Ag co-reduction potential of −0.474 V. The Sn-Ag bumps were fabricated successfully without serious defects by electroplating without a PR mould. The bump height and width increased to 14.5 and 72.0 μm, respectively, when the plating time was raised to 15 min. The growth of the bump width was caused by the absence of the PR mould. The Sn-Ag bump exhibited rivet-head morphology in 15 min plating, and no short circuit between neighboring bumps was found. The near eutectic composition of Sn-3.24 wt%Ag bump was obtained by plating at −30 mA/cm2 for 15 min.
    Metals and Materials International 06/2012; 18(3). · 1.22 Impact Factor
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    ABSTRACT: The characteristics of electroplated Sn bumps, fabricated without a PR (photoresist) mould on copper-plugged TSVs (through-silicon vias), in a Si chip were investigated. A new process of non-PR bumping developed in this research was considered to enhance the productivity and reduce the cost for three-dimensional (3D) chip stacking. To produce Sn bumps, Pt was adopted as an anode, and thinned Si die with Cu-plugged TSVs as a cathode. The polarization curve of the Sn electrolyte was analysed to determine the reduction potential of the Sn ion. The heights, widths, and uniformities of the Sn bumps produced through the proposed non-PR process were evaluated to assess the feasibility of reliable Sn bumping using this process. The experimental results showed that the Sn electrolyte had a reduction potential of −0.463 V. The Sn bumps with rivet-head shapes were produced successfully without a PR mould on Cu-plugged TSV. The Sn bumps grew in both vertical (thickness) and lateral (width) directions due to the absence of a PR mould. The plating time was varied from 2 to 60 min at a constant current density of −30 mA/cm2, and the bump height and width became 39 and 76 μm at 60 min, respectively. The morphologies of the Sn bumps without a PR mould showed the preferred facet growth by increasing the plating time, which resulted in increase of Sn facet size but decrease of number of facets. The uniformity of the bump widths on a chip was within the range of 86.9–95.4%.
    Microelectronic Engineering 05/2012; 93:85–90. · 1.34 Impact Factor
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    ABSTRACT: PURPOSE: Varicose vein incompetence in the legs is very prevalent in the Korean population. New technologies and improvements in established methods have changed the treatment of varicose veins. Transilluminated powered phlebectomy is an alternative surgical technique that combines endoscopic powered vein resection and ablation of superficial varicosities with tumescent anesthesia and irrigated illumination. The present study sought to determine the clinical efficacy and safety of transilluminated powered phlebectomy from clinical data. METHOD: Four hundred and forty-seven limbs in 299 patients (157 male, 142 female; mean age 50.6 years) with varicose veins were treated with transilluminated powered phlebectomy over a 7-year period. The patients were followed for 1 year postoperatively. The analyzed data included sex, age, body mass index, operative time (from skin incision to the application of elastic bandages on the legs for compression purposes), and postoperative complications. RESULTS: The mean operative time was 87.2 min for both limbs and 57.3 min for single limbs. The median number of incisions was five. Postoperative complications included an episode of cellulitis in 10 patients (2.2%), wound abscess in two patients (0.4%), hematoma in 15 patients (3.4%), residual veins in five patients (1.1%), cutaneous nerve damage in 10 patients (2.2%), and seroma in 13 patients (2.9%). No skin perforation and deep venous thrombosis were observed at the 1-year follow-up. CONCLUSION: Transilluminated powered phlebectomy is an effective and safe method for the excision of varicosities.
    Surgery Today 03/2012; · 1.21 Impact Factor
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    ABSTRACT: Many surgeons have found it difficult to decide whether to apply percutaneous transhepatic gallbladder drainage (PTGBD) in patients with acute cholecystitis that is not responsive to initial medical management (IMMx), because the indications of PTGBD are ambiguous. The aim of this study was to evaluate the appropriate treatment for acute cholecystitis that is not responsive to IMMx. Specifically, we focused on differences in surgical outcomes between elective and emergency laparoscopic surgeries. Between March 2006 and February 2009, 738 patients with acute cholecystitis who had undergone laparoscopic cholecystectomy (LC) at our institution were retrospectively studied. We divided them into 3 groups. Group I included 494 patients who underwent elective LC without pre-operative PTGBD, group II included 97 patients who intended to undergo elective LC after preoperative PTGBD, and group III included 147 patients who underwent emergency LC without preoperative PTGBD. We compared age, sex, symptom duration, body temperature, leukocyte counts, and American Society of Anesthesiologists (ASA) class on admission as clinical characteristics. We compared the time interval from symptom development and admission to surgery, operative time, the conversion rate to open surgery, postoperative complications, the total length of stay, and the postoperative length of stay as perioperative surgical outcomes. For patients with ASA 2 and 3, the conversion rate to open surgery in group II was significantly less than that in group III (P<.05, P<.01, respectively). We recommend PTGBD as the first choice for acute cholecystitis in patients who show no improvement after IMMx, to allow the patient to undergo an elective LC rather than emergency surgery for patients with ASA 2 and 3.
    Journal of Laparoendoscopic & Advanced Surgical Techniques 12/2011; 21(10):941-6. · 1.19 Impact Factor
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    ABSTRACT: The reduction of defects and high-speed copper filling into a through-silicon-via (TSV) for the three-dimensional stacking of Si chips were investigated. The via, with a diameter and depth of 30μm and 60μm, respectively, was prepared on a Si wafer by a deep reactive ion etching (DRIE) process. SiO2, Ti, and Au layers were coated as functional layers on the via wall. In order to increase the filling ratio of Cu into the via, a 3-step periodic-pulse-reverse (PPR) current waveform was suggested for electroplating. The 3-step PPR consisted of low, medium and high current densities for the 1st, 2nd and 3rd steps, respectively. After Cu filling, in order to estimate defects in the Cu-filling, the via was cross-sectioned and observed by field emission scanning electron microscopy (FE-SEM), and also an X-ray radiographic test was performed for non-destructive inspection. The experimental results showed the via was fully filled without a serious defect by the 3-step PPR process after 80min of plating, specifically, by current densities of −1.24, −3.22, and −9.89mA/cm2 (1st/2nd/3rd step, respectively). The 3-step PPR filling was a kind of bottom-up filling process of Cu into the via, and it was effective for Cu filling in a short time. Defects, like voids in the Cu-filled TSV, were identified by the X-ray radiographic test, which can be useful for ensuring the reliability of a fragile thin Si wafer for 3D packaging.
    Microelectronics Reliability 12/2011; 51:2228-2235. · 1.21 Impact Factor
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    ABSTRACT: We report a case of synchronous double primary tumor of gallbladder and liver. A 63-year-old male was admitted to the hospital complaining of abdominal discomfort. Enhanced computed tomography of the abdomen showed acute cholecystitis with tiny gallbladder stones and a 2.2 cm size enhanced nodule in the left lobe of the liver. Under the impression of acute cholecystitis with gall bladder stones and hepatocellular carcinoma of the left Liver, the patient underwent a laparotomy. At laparotomy, a mass was palpated on the surface of the neck portion of the gall bladder. Intraoperative frozen diagnosis revealed adenocarcinoma of the gall bladder. The patient was diagnosed as having gall bladder cancer and hepatocellular carcinoma, so extended cholecystectomy with dissection of regional lymph nodes and left hemihepatectomy were performed. Histological examination revealed moderated differentiated adenocarcinoma of gallbladder and hepatocellular carcinoma of liver. To our knowledge, the simultaneous occurrence of primary malignant tumor of the gallbladder and liver has never been published before. The patient is doing well with no evidence of recurrence 17 months after surgery.
    World Journal of Surgical Oncology 08/2011; 9:84. · 1.20 Impact Factor
    This article is viewable in ResearchGate's enriched format
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    ABSTRACT: Chip stacking with through-silicon-vias (TSV) technology for 3-D packaging of electronic devices was investigated. A new process of direct solder bumping on Si wafers without photoresist (PR) mould was designed and applied in this study. The Cu extrusion process on the via was also omitted for process simplification. This simplified process can be useful for cost reduction and increased productivity. The substrate for the experiments was a p-type 〈100 〉 Si wafer of 100 mm diameter. In order to produce the vias, the Si wafer was etched by a deep reactive ion etcher (DRIE) using SF<sub>6</sub> and C<sub>4</sub>F<sub>8</sub> plasmas alternately. The produced vias were 40 μm in diameter and 80 μm in depth. On the via side walls, SiO<sub>2</sub>, Ti, and Au layers were formed with thicknesses of 1, 0.1, and 0.7μm, respectively. Pulsed direct current (DC) electroplating was used to fill the vias with Cu. Then the Si wafer was back ground to a thickness of 80 μm until the Cu filling in the vias was exposed to the surface without extrusion. Plating current subsequently flowed through the vias to the bumping surface, and Sn was electroplated on the Cu filling directly without a PR mould. To optimize the bumping process, the current density and time for Sn plating were varied from 0.04 to 0.06 A/cm<sup>2</sup> and from 10 to 40 min, respectively. Bumps with a height of 20 μm were formed successfully with 0.05 A/cm<sup>2</sup> and 30 min without a PR mould. The bump height increased with increasing plating current and time; for example, from 13 μm at 10 min to 33 μm at 40 min in case of 0.06 A/cm<sup>2</sup>. The Si dice with electroplated Sn bumps had dimensions of 5 × 5 mm and thickness of 80 μm. Three Si dice were stacked successfully by micro-soldering at 260°C. In the interface between the Sn bumps and the Cu filling, a Cu<sub>6</sub>Sn<sub>5</sub> intermetallic compound was pr- - oduced with a thickness of 3.2 μm. Through this study, a process for non-PR solder bumping by electroplating and wafer stacking with TSV was achieved successfully.
    IEEE Transactions on Advanced Packaging 12/2010; · 1.12 Impact Factor
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    ABSTRACT: The resistance spot weldability of AZ31B magnesium alloy using AC (alternating current) was investigated in this paper. The surfaces of sheet coupons were prepared by acetone cleaning (as-received) and some coupons were also cleaned with chromic acid (H2Cr2O7) after acetone cleaning (acid-cleaned). The surfaces of the as-received AZ31B sheets consisted of MgO, Mg(OH)2, and MgCO3. The extent and thickness of the surface oxide/reaction layer of the sheets varied according to the fabrication process of the sheets, and resulted in different contact resistance. Effects of welding current and weld time were investigated while the electrode force was kept constant. The results indicated that the as-received sheets produced expulsion both at the faying surface and at the work piece/electrode interface due to high contact resistance. Diluted chromic acid cleaning reduced contact resistance and produced good weld quality. Increasing the welding current and weld time enhanced not only the nugget size and joint strength, but also increased indentation on the weld surfaces. A weld lobe was established considering the minimum joint strength, weld expulsion, and surface indentation based on a relevant American Welding Society Standard.
    Metals and Materials International 12/2010; 16(6):967-974. · 1.22 Impact Factor
  • Journal of Electronic Packaging 01/2009; 131:041007-1. · 0.65 Impact Factor
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    ABSTRACT: Reliability of QFP (quad flat package) solder joints after thermal shock was investigated for PCB’s and connecting leads plated with several different alloy coatings before soldering. Sn–8 wt%Zn–3 wt%Bi (hereafter, Sn–8Zn–3Bi) was selected as a solder, and FR-4 PCB’s finished with Cu/Sn, Cu/OSP and Cu/Ni/Au were used as substrates. The leads of the QFP were Cu plated with Sn–10 wt%Pb, or Sn, or Sn–3 wt%Bi. The QFP chips were mounted on the substrates using a Sn–8Zn–3Bi solder paste and reflowed in air atmosphere. The pull strength and microstructure for the soldered leads of QFP were evaluated before and after thermal shock testing. The leads plated with Sn or Sn–3Bi showed approximately 40–50% higher pull strength than the reference value of a Sn–37%Pb solder joint for all PCB-finishes. However, in the case of leads coated with Sn–10Pb, the pull strength of the leads soldered to a Sn-finished PCB was 21% lower than the reference value. In microstructure analysis of the joints with Sn–10Pb-plated leads, cracks were found along the bonded interface for Sn-finished PCB. The cracks were believed to start from the low melting temperature phase, 49.38 wt% Pb–32.58 wt%Sn–18.03 wt%Bi, found around the crack, and then propagated through Cu–Zn intermetallic compound. Meanwhile, even when using Sn–10Pb-plated leads, the PCB’s finished with Cu/Ni/Au coating had about 30% higher strength than the reference value, and cracks were hardly found on the soldered joint. Thus, even with Sn–10Pb-plated leads the Cu/Ni/Au-finished PCB’s were evaluated to be as reliable as the reference joint.
    Microelectronics Reliability 04/2008; · 1.21 Impact Factor
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    ABSTRACT: Primary liposarcoma of the liver is extremely rare. We report here on a case of primary well-differentiated liposarcoma in the left hepatic lobe of a 63-year-old woman. Abdominal ultrasonography showed a well-defined, echogenic, round mass. Abdominal computed tomography (CT) and magnetic resonance (MR) images showed an almost fatty, lobulated mass with a few, random distributed vascular structures and a small area of nodular enhancement. The resected tumor appeared as a well-defined, round, tan-yellow mass. Histological analysis showed a well-differentiated liposarcoma.
    Acta Radiologica 01/2008; 48(10):1061-5. · 1.35 Impact Factor

Publication Stats

74 Citations
37.68 Total Impact Points


  • 1999–2014
    • University of Seoul
      • Depatrment of Materials Science and Engineering
      Sŏul, Seoul, South Korea
    • Seoul National University
      • Department of Materials Science and Engineering
      Seoul, Seoul, South Korea
  • 2011–2012
    • Hallym University Medical Center
      Sŏul, Seoul, South Korea
  • 2008
    • Asan Medical Center
      Sŏul, Seoul, South Korea