SAC305 및 나노 입자 분산 솔더의 특성

김장백,서성민,강혜준,조도훈,스리 하리니 라젠드란,정재필,Kim, Jang Baeg,Seo, Seong Min,Kang, Hye Jun,Cho, Do Hoon,Rajendran, Sri Harini,Jung, Jae Pil 한국마이크로전자및패키징학회 2021 마이크로전자 및 패키징학회지 Vol.28 No.1

Sn-3wt%Ag-0.5wt%Cu (SAC305) solder is most popular solder in electronics industry. However, SAC305 has also drawbacks such as growth of β-Sn phase, intermetallic compounds (IMCs) of Ag3Sn, Cu6Sn5 and Cu3Sn which can result in deterioration of solder joints in terms of metallurgically, mechanically and electrically. Thus, improvement of SAC305 solders have been investigated continuously by addition of alloying elements, nano-particles and etc. In this paper, recent improvements of SAC solders including nano-composite alloys and related solderabilty and metallurgical and mechanical properties are investigated.

TSV (Through-Si-Via) 기술을 이용한 반도체의 3차원 적층 실장

조도훈(Do Hoon Cho),강혜준(Hye Jun Kang),서성민(Seong Min Seo),김장백(Jang Baeg Kim),스리하리니 라젠드란(Sri Harini Rajendran),정재필(Jae Pil Jung) 대한용접·접합학회 2021 대한용접·접합학회지 Vol.39 No.3

Recently, the electronics industry is developing toward artificial intelligence, the Internet of things, fifth-generation technology, and high-performance computing. High-density electronics packaging, high speed, high performance, and miniaturized size are required to satisfy these trends. Three-dimensional Si-chip stacking using through-Si via (TSV) has attracted the attention of industries related to these requirements. In this study, TSV fabrication using the deep reactive ion-etching process and the coating of functional layers on the TSV wall, such as insulating, adhesion, and seed layers, were investigated. In addition, Cu electroplating in the TSV was analyzed in detail. The solutions to other accompanied technical barriers for packaging high-density electronics can improve smartness and convenience.

New High Entropy Alloy (HEA) Reinforced SAC 305 Solder

Sri Harini Rajendran(라젠드란 스리 하리니),Hye Jun Kang(강혜준),Jae Pil Jung(정재필) 대한용접·접합학회 2021 대한용접학회 특별강연 및 학술발표대회 개요집 Vol.2021 No.5

In order to meet the demands for the developing packaging technologies and to be in pace with the WEEE (2012-19-EU) and RoHS (2002-95-EU) implementations, series of lead-free solders has been developed. Sn-3.0Ag-0.5Cu and Sn-58Bi are the interesting solders fulfilling the demands and environmental standards of consumer electronic industries. However, the brittle phases remain a serious threat in terms of mechanical reliability. Many methods have been adopted by the researches to enhance the reliability of existing solders such as micro-alloying and the addition of second phase particles. However, the quest for new solders remains among the researchers. In the present work, new high entropy alloys have been incorporated in the soldering field. Varying compositions of high entropy solder reinforced SAC alloys were prepared by mechanical mixing. The solder paste was printed and reflowed with 1608 chip capacitor. The microstructure and intermetallic phase evolution along the solder/capacitor for the high entropy solder addition has been characterized by scanning electron microscope. The optimum composition with good solderability were analyzed using wetting and spreading test (JIS-Z-319). The shear tests were analyzed for the mechanical reliability and the data is interpreted using Weibull statistical distribution. High entropy solders added have optimistic microstructure and solderability. Besides, high entropy solders are found to be beneficial in their mechanical properties.

Microstructure and Mechanical Characteristics of Inconel 600 to Nickel alloy and Stainless Steel Joints by Fiber Laser Welding

Do Hoon Cho(조도훈),Sri Harini Rajendran,Hye Jun Kang(강혜준),Jae Pil Jung(정재필) 대한용접·접합학회 2021 대한용접학회 특별강연 및 학술발표대회 개요집 Vol.2021 No.5

The nickel-based superalloy of Inconel 600 containing high chromium content was developed as a superior corrosion resistance in acidic environments. Since the Inconel 600 shows high corrosion resistance and good fatigue strength, the Inconel 600 has been utilized in high temperature environments such as heat treatment furnace parts and industrial vacuum equipment components. Inconel X-750 is also a austenitic nickel alloy, is widely used in heat exchanger, chemical containers and metallurgical industries because of its good corrosion resistance and heat resistance. Fiber laser welding is an advanced welding method which gives high energy density, minimization of heat-affect zone, high heating-cooling speed, less thermal-stress, and so on. The joint can be applicable to the high temperature parts such as various engine and airframe components, exhaust liners, muffles, turbine seals and etc. In the present study, Inconel 600 and X-750 were welded using QCW fiber laser from IPG and their microstructure and the mechanical properties were analyzed. The experimental results showed that Inconel 600 and Inconel X-750 were welded successfully with good bead appearance. The welded joint gave deep penetration, and the microstructure of fusion zone exhibited mainly columnar dendrites. The as-welded samples were subjected to heat treatment at various temperature. The microstructure of the weld pool and the corresponding tensile strength & elongation for welded joints were characterized from Scanning Electron Microscope and weld-joint tensile tests. The hardness of the weld zone before and after heat treatment were evaluated using Vickers micro hardness tester.

Active Metal Brazing of Al2O3-Cu Joints Using Multicomponent Ag-Cu-Sn-Zr-Ti Filler for Electric Vehicle

Seong Min Seo(서성민),Sri Harini Rajendran(라젠드란 스리 하리니),Hye Jun Kang(강혜준),Jae Pil Jung(정재필) 대한용접·접합학회 2021 대한용접학회 특별강연 및 학술발표대회 개요집 Vol.2021 No.5

In recent years, growing demand in electronic industry for highly reliable products emphasize number of components involving metal ceramic combination. Wide range of ceramics like Al2O3, AlN, SiC are used as substrate materials for high power electronics to ensure reliable operations in aerospace, automotive and military industry as well in consumer electronics. Several bonding methods like partial transient liquid-phase bonding, diffusion bonding, brazing and glass adhesive bonding have been developed for ceramic-metal joining out of which active metal brazing is the most versatile bonding method adopted by the engineering industries. Ag-Cu-Sn-Ti fillers have received much attention in recent years due to their low bonding temperature and excellent wetting with ceramics. Due to the developments in engineering, recently multicomponent fillers are emerging. The Al2O3-Cu joint is applicable to an electric vehicle parts. This study was designed to investigate the active metal brazing of Al2O3 ceramic to copper brazed, using the multicomponent Ag-Cu-Sn-Zr-Ti filler alloy. Numerous fine and hexagonal-shaped rod-like ternary intermetallic (Zr, Ti)5Sn3 phase were found dispersed in the Ag-Cu matrix of Ag-18Cu-6Sn-3Zr-1Ti alloy. An approximate 15° reduction in contact angle and 3.1 °C reduction in melting point are observed upon the incorporation of Ti and Sn in Ag-18Cu-3Zr filler. Interestingly, the interface microstructure of Al2O3/Cu joints brazed by using Ag-18Cu-6Sn-3Zr-1Ti filler shows a double reaction layer: a discontinuous Ti-rich layer consisting of (Cu, Al)3(Ti, Zr)3O, TiO, and in-situ Cu-(Ti, Zr) precipitates on the Al2O3 side and continuous Zr-rich layer consisting of ZrO2 on the filler side. The shear strength achieved in Al2O3/Cu joints brazed with Ag-18Cu-6Sn-3Zr-1Ti filler is 31% higher, compared to the joints brazed with Ag-18Cu-6Sn-3Zr filler. Failure analysis reveals a composite fracture mode indicating a strong interface bonding in Al2O3/Ag-18Cu-6Sn-3Zr-1Ti filler/Cu joints. The findings will be helpful towards the development of high entropy brazing fillers in the future.

ZnO Nano-particle-reinforced Sn58Bi Low Temperature Solder for Flexible Display Application

Jang Baeg Kim(김장백),Sri Harini Rajendran(라젠드란 스리 하리니),Hye Jun Kang(강혜준),Jae Pil Jung(정재필) 대한용접·접합학회 2021 대한용접학회 특별강연 및 학술발표대회 개요집 Vol.2021 No.5

With the WEEE (2012-19-EU) and RoHS (2002-95-EU) implementation, series of lead-free solders has been developed to meet the demands for various temperature ranges. Sn-58Bi solder is an interesting low-temperature candidate which meets the environmental standards of consumer electronics with good structural and mechanical reliability. However, presence of coarse Bi phase remains a serious concern in terms of mechanical reliability. Many methods have been adopted by the researches to enhance the reliability of Sn-Bi solders such as micro-alloying and the addition of second phase nanoparticles. Whereas nanoparticles are found to enhance the mechanical properties to a greater extent. The Sn58Bi low temperature solder can be applied to flexible display application. In the present work, ZrO2 nanoparticles were used as an additive in Sn-58Bi solder. The microstructure and spreading of Sn58Bi nanocomposite solder have been characterized by Scanning electron microscope and spreading test. Addition of ZnO nanoparticles is found to reduce the Sn-Bi interphase spacing and enhanced the spreading kinetics of Sn58Bi solder. Also, nanoparticles enhanced the tensile strength of Sn58Bi solder by dispersion strengthening. Ductility of Sn58Bi solder is enhanced for lower ZnO additions with dominant bulge fracture. However, at higher additions fracture surface is dominated by cleavage fracture.

Nanocomposite SAC Solders for Improving Reliability of Soldering Technology

Young Kyu Hong(홍영규),Sri Harini Rajendran(라젠드란 스리 하리니),Hye Jun Kang(강혜준),Jae Pil Jung(정재필) 대한용접·접합학회 2021 대한용접학회 특별강연 및 학술발표대회 개요집 Vol.2021 No.5

Nanocomposite Sn-Ag-Cu solders are the potential candidates in the advanced integrated circuit packaging such as flip-chip, and ball grid arrays. Sn-Ag-Cu solders are eco-friendly with desirable thermal and mechanical characteristics. In recent nanotechnology era, addition of nanoparticles in the solder matrix is explored widely as the nanoparticles to have a positive contribution in the Ag3Sn refinement, interfacial Cu6Sn5 suppression and the reliability of the solder joints. However, the contribution of nanoparticles in aging characteristics is still under investigation. In the present work, the shear strength and aging characteristics of Sn-3.0Ag-0.5Cu (SAC 305)/Cu joints by the addition of ZrO2 nanoparticles are investigated. Nanocomposite pastes are fabricated by mechanically mixing ZrO2 and the solder paste. Addition of ZrO2 nanoparticles decreased theβ-Sn grain size and Ag3Sn intermetallic compound (IMC) in the matrix and reduced the Cu6Sn5 IMC thickness at the interface of lap shear SAC 305/Cu joints. The solder joints were isothermally aged at 175˚C for 24, 48, 144 and 256 hours. ZrO2 addition decreased the diffusion coefficient from 1.74 x 10 -16 m/s to 3.83 x 10 -17 m/s, thereby reducing the growth of Cu-Sn IMC at the interface. The shear strength of the solder joints decreased with the aging time due to an increase in the thickness of interfacial IMC and coarsening of Ag3Sn in the solder. However, higher shear strength exhibited by SAC 305-ZrO2/Cu joints was attributed to the fine Ag3Sn IMC’s dispersed in the solder matrix.