플립 칩 BGA에서 2차 레벨 솔더접합부의 신뢰성 향상

김경섭,이석,장의구,Kim, Kyung-Seob,Lee, Suk,Chang, Eui-Goo 대한용접접합학회 2002 대한용접·접합학회지 Vol.20 No.2

FC-BGA has advantages over other interconnection methods including high I/O counts, better electrical performance, high throughput, and low profile. But, FC-BGA has a lot of reliability issues. The 2nd level solder joint reliability of the FC-BGA with large chip on laminate substrate was studied in this paper. The purpose of this study is to discuss solder joint failures of 2nd level thermal cycling test. This work has been done to understand the influence of the structure of package, the properties of underfill, the properties and thickness of bismaleimide tiazine substrate and the temperature range of thermal cycling on 2nd level solder joint reliability. The increase of bismaleimide tiazine substrate thickness applied to low modulus underfill was improve of solder joint reliability. The resistance of solder ball fatigue was increased solder ball size in the solder joints of FC-BGA.

플라스틱 BGA 솔더접합부의 고신뢰성에 관한 연구

김경섭,신영의,이혁,Kim, Kyung-Seob,Shin, Young-Eui,Lee, Hyuk 대한용접접합학회 1999 대한용접·접합학회지 Vol.17 No.3

The increase in high speed, multi-function and high I/O pin semiconductor devices highly demands high pin count, very thin, and high density packages. BGA is one of the solutions, but the package has demerits in package reliability, surface mounting problems due to the PCB warpage and solder joint crack related with TCE mismatch between the materials. On this study to verify the thermal fatigue lifetime of the solder joint FEM and experiments were performed after surface mounting BGA with different solder composition and reliability conditions. FEM showed optimum composition of Ag3.2-Sn96.5 and under the composition minimum creep deformation of the solder joint was calculated, and the thermal fatigue lifetime was improved. In view of temperature cycle condition, the conditions of $-65^{\circ}C$to $150^{\circ}C$ showed minimum lifetime and t was 1/3 of $0^{\circ}C$ to $125^{\circ}C$ condition. Test board was prepared and solder joint crack was verified. Until 1000cycle on soder joint crack was observed.

무연솔더 도금된 리드프레임에서 Sn 위스커의 성장과 구조

김경섭,임영민,유정희,Kim Kyung-Seob,Leem Young-Min,Yu Chong-Hee 한국마이크로전자및패키징학회 2004 마이크로전자 및 패키징학회지 Vol.11 No.3

주석 도금은 특정 환경하에서 위스커를 발생시키며, 이는 전자부품의 불량을 초래한다. 최근 세계곳곳에서는 환경보호를 위해 "무연"의 사용을 권고하고 있다. 본 논문에서는 두 종류 무연 도금 재료에서 도금 온도와 신뢰성시험 하에서 성장하는 위스커를 평가하였다. 도금 온도가 높아질수록 표면에 형성되는 도금 입자의 크기는 커지고, 위스커의 성장은 작아진다. 또한 온도 순환시험에서 성장한 위스커는 무광택 Sn 도금은 굽은 모양을, 무광택 Sn-Bi에서는 줄무의 모양이 관찰되었고, Sn 도금에 비해 Sn-Bi에서 위스커가 작게 성장하였다. 무광택 Sn 도금된 FeNi42 리드프레임은 TC 300 사이클에서 직경이 $7.0{\~}10.0{\mu}m$이고, 길이가 $25.0{\~}45.0{\mu}m$인 위스커가 성장하였다. 또한 Cu는 300 사이클에서는 표면에 노듈(핵 상태)만이 관찰되었고, 600 사이클에서 길이가 $3.0{\~}4.0{\mu}m$의 위스커로 성장하였다. TC 600 사이클 후 FeNi42는 계면에서 ${\~}0.34{\mu}m$의 얇은 $Ni_3Sn_4$가, Cu에서는 두께가 $0.76{\~}l.14{\mu}m$인 $Cu_6Sn_5$와 ${\~}0.27{\mu}m$의 $Cu_3Sn$ 화합물들이 두껍게 성장하였다. 따라서 FeNi42 리드프레임은 열팽창계수의 차이, Cu에서는 금속간 화합물의 형성이 위스커의 성장에 영향을 미치는 주요 인자이다. Tin plating on component finishes may grow whiskers under certain conditions, which may cause failures in electronics equipment. To protect the environment, 'lead-free' among component finishes is being promoted worldwide. This paper presents the evaluation results of whiskers on two kinds of lead-free plating materials at the plating temperature and under the reliability test. The rising plating temperature caused increasing the size of plating grain and shorting the growth of whisker. The whisker was grown under the temperature cycling the bent type in matt Sn plating and striated type in malt Sn-Bi. The whisker growth in Sn-Bi plating was shorter than that in Sn plating. In FeNi42 leadframe, the $7.0{\~}10.0{\mu}m$ diameter and the $25.0{\~}45.0{\mu}m$ long whisker was grown under 300 cycles. In the 300 cycles of Cu leadframe, only the nodule(nuclear state) grew on the surface, and in the 600 cycles, a $3.0{\~}4.0{\mu}m$ short whisker grew. After 600 cycles, the ${\~}0.34{\mu}m$ thin $Ni_3Sn_4$ formed on the Sn-plated FeNi42. However, we observed the amount of $0.76{\~}1.14{\mu}m$ thick $Cu_6Sn_5$ and ${\~}0.27{\mu}m$ thin $Cu_3Sn$ intermetallics were observed between the Sn and Cu interfaces. Therefore, the main growth factor of a whisker is the intermetallic compound in the Cu leadframe, and the coefficient of thermal expansion mismatch in FeNi42.

${\mu}BGA$ 패키지에서 솔더 볼의 초기 접합강도와 금 확산에 관한 연구

김경섭,이석,김헌희,윤준호,Kim, Kyung-Seob,Lee, Suk,Kim, Heon-Hee,Yoon, Jun-Ho 대한용접접합학회 2001 대한용접·접합학회지 Vol.19 No.3

This paper presents that the affecting factors to the solderability and initial reliability. It is the factor that the coefficient of thermal expansion between package and PCB(Printed Circuit Board), the quantity of solder paste and reflow condition, and Au thickness of the solder ball pad on polyimide tape. As the reflow soldering condition for 48 ${\mu}BGA$ is changed, it is estimated that the quantity of Au diffusion at eutectic Sn-Pb solder surface and initial bonding strength of eutectic Sn-Pb solder and lead free solder. It is the result that quantitative measurement of Au diffusion quantity is difficult, but the shear strength of eutectic Sn-Pb solder joint is 842 mN at first reflow and increases 879 mN at third reflow. The major failure mode in solder is judged solder fracture. So, Au diffusion quantity is more affected by reflow temperature than by the reflow times.

4호선 전동차 하부세정설비 운용효과에 관한 연구

김경섭(Kyung Seob Kim),최덕수(Duk Soo Choi),배명곤(Myung Gon Bae),김택주(Taeg Joo Kim) 한국철도학회 2016 한국철도학회 학술발표대회논문집 Vol.2016 No.5

전동차 하부 주요기기에 부착된 먼지 및 이물질은 주요기기의 과온을 유발하여 고장을 발생시킨다. 4호선 전동차의 경우 2011년에는 14건으로 가장 많은 고장을 발생시켰으며, 중정비(3년 검사)을 통해서 공기 청소를 시행하였다. 그러나 중정비 본연의 임무수행에 막대한 지장이 초래되었으며, 자체적으로 공기 청소를 실시하였으나 주변 주민의 민원으로 어려움에 직면했다. 이와 같은 문제점을 해소하기 위하여 전동차 하부 세정설비를 설치하게 되었다. 이 장치의 단점은 첫째, 발생하는 먼지가 대기로 유출되는 것을 완벽하게 차단단다. 둘째, 대기환경 보호는 물론이고 역사 및 터널의 공기질 향상에 기여한다. 셋째, 작업장 이물질 유입을 방지하여 직원의 근무환경에도 상당한 개선효과가 있었으며, 전동차 주요기기의 과온을 사전에 예방하여 전동차 안전운행에 기여하였다. The dust and dirt attached to the lower of train main device caused failure by the over-temperature of the main device. In the case of line 4 train, Failures have caused 14 cases the most trouble in 2011, through the heavy maintenance (3 Year inspection). The heavy maintenance was a huge hindrance caused to perform your duties. The lower cleaning was been carried out in-house but faced difficulties from dust complaints. It was been installed to the train lower washing equipment in order to solve the above problems. The device is can completely blocked to the dust generated during cleaning air. Advantage is the first protects the environment of the atmosphere. Second, contribute to the improvement of air quality internal station and tunnels. Third, to prevent hazardous matter entering the workplace was a significant improvement in the working conditions of employees. In addition, by preventing the over-temperature of the main device by the dust contributed to safe driving.

[E-1] 나선 주름모양 가스수송용 파이프의 변형특성에 관한 수치적 연구

김경섭(Kyung Seob Kim),김청균(Chung Kyun Kim) 한국가스학회 2010 한국가스학회 학술대회논문집 Vol.2010 No.10

유한요소법을 이용한 파이프 리듀서의 변형특성 해석

김경섭(Kyung Seob Kim),김청균(Chung Kyun Kim) 한국가스학회 2009 한국가스학회 학술대회논문집 Vol.2009 No.10

Pipe reducer has been widely used as they are easy to construct and suitable for economical efficiency when they are compared with any other joint methods. In this paper, we studies the effect of von mises stress, total strain and Y-axis displacement at constant inner pressure and changed angle of corrugation with the SUS316 pipes using Finite Element Method. (EFM) As a result, von mises stress and total strain have been increased according to the internal radius of reducer. And displacement of reducer increased linearly as around bottom toward horizontal direction. Also, change of reducer radius showed that the deformation characteristics, respectively.

가스 · 연료를 수송하는 주름 파이프의 거동특성에 관한 수치적 연구

김경섭(Kyung Seob Kim),김청균(Chung Kyun Kim) 한국가스학회 2009 한국가스학회 학술대회논문집 Vol.2009 No.10

In this study, we studies the effect of von mises stress, total strain and Y-axis displacement at constant inner pressure and changed angle of corrugation with the SUS316 pipes using Finite Element Method.(FEM) As a result, von mises stress and total strain have been occur to circumferential of corrugation screw thread. And displacement increased the other side of corrugation pipe toward horizontal direction. According to the change of corrugation angle when pipe unchanged corrugation screw thread showed that the deformation characteristics.

소방 배관용 브라켓의 변형특성에 관한 수치적 연구

김경섭(Kim, Kyung-Seob),김청균(Kim, Chung-Kyun) 한국화재소방학회 2010 한국화재소방학회 학술대회 논문집 Vol.2010 No.추계

본 연구에서는 배관계에 가해진 압력으로 인하여 변형된 배관에 의하여 영향을 받는 브라켓에 대하여 여러 가지 형상으로 모델링하여 유한요소해석을 통하여 브라켓의 형상변화가 변형특성에 미치는 영향을 고찰 하였고, 배관시스템의 브라켓의 강도 안전성을 확보하기 위하여 산업공학에서 쓰였던 다구찌방법을 도입하여 최적화 설계를 하는 것이 본 연구의 목적이다.

스프링쿨러 소방 배관용 시일의 최적설계에 관한 연구

김경섭(Kim, Kyung-Seob),김청균(Kim, Chung-Kyun) 한국화재소방학회 2010 한국화재소방학회 학술대회 논문집 Vol.2010 No.추계

본 연구는 최적설계 기법의 하나인 다구찌 방법을 이용하여 소방용 스프링클러 배관용 밀봉부에 대한 유한요소해석을 수행하고, 이를 통하여 소방용 배관의 밀봉안전성을 확보하고자 한다.