• Title/Summary/Keyword: Sn-37%Pb

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A study on the characteristics of low Pb Sn-5%Pb-1.5%Ag-x%Bi solder alloys (저Pb Sn-5%Pb-1.5%Ag-x%Bi계 솔더 합금의 특성에 관한 연구)

  • 홍순국;주철홍;강정윤;김인배
    • Journal of Welding and Joining
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    • v.16 no.3
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    • pp.157-166
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    • 1998
  • Recently as environmental pollution caused by Pb has posed a serious threat to the global environment, the trend to regulate the usage of Pb in electronic industry is one the rise. Currently, the solder alloy with high Pb content, Sn-37%Pb, is utilized in the electronic assembly therefore, the objective of this study is to develop an alternative solder alloy for the existing Sn-37%Pb solder alloy. First thing, this work choosed Sn-5%Pb-1.5%Ag, Sn-5%Pb-1.5%Ag-x%Bi(x=1~5%) for candidate solder alloys, and examined their properties such as melting range, wettability, microhardness, tensile property, oxidation behavior and microstructure. Wettability was on the same level of Sn-37%Pb. Dissolution of Pb ion in Sn-5%Pb solder was 0.46ppm. This solder alloy revealed cellular dendrite microstructure $\beta$-Sn matrix, Pb-rich phase, Ag/Sn, and Cu/Sn Intermetallic compounds. The range of solidification temperature was within 3$0^{\circ}C$. Also these alloy displayed higher tensile strength and lower elongation than Sn-37%Pb. The resistance of oxidation in Sn-5%Pb-1.5%Ag solder alloy was superior to that of Sn-37%Pb solder alloy. But that of Sn-5%Pb-1.5%Ag-5%Bi solder alloy was equal to that of Sn-37%Pb solder alloy.

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A Study on the Characteristics of Low Pb Sn-5%Pb-1.5%Pb-1.5Ag-x%In Solder Alloys (저 Pb Sn-5%Pb-1.5%Ag-x%In계 솔도 합금의 특성에 관한 연구)

  • Hong, Sun-Guk;Ju, Cheol-Hong;Gang, Jeong-Yun;Kim, In-Bae
    • Korean Journal of Materials Research
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    • v.8 no.11
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    • pp.1011-1019
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    • 1998
  • This work designed Sn-5%Pb-1.5%Ag-x%In solder alloy to develop the solder alloy with low Pb content. This solder alloy doesn't cause environmental pollution. and this study reviewed the probability of replacement of Sn-37%Pb solder as evaluation of melting range, wettability. microstructure, microhardne'ss, tensile strength, drossability of this new solder alloys. The level of international regulation in dissolution amount of Pb ion was 3ppm. But dissolution amount of Pb ion in Sn-5%Pb solder alloy confirmed not to threat the global environmental is 0.46ppm. The melting range of this solder alloy was $183-192^{\circ}C$. Also the range of solidification was very narrow within $5^{\circ}C$. The wettability was similar to Sn-37%Pb solder, and the effect of amount of In addition of wettability couldn't be founded. The probability of replacement in the melting range and wettability is very high. And microhardness of this solder alloy was 1.5 times of conventional type solder. Tensile strength of new solder alloys was a little high than that of conventional type solder. With increasing amount of In% addition, tensile strength was increased, but elongation was decreased. The solder alloy of l%In addition revealed AgSn and Pb on dendrite microstructure boundary, and $Ag_3Sn$, $Ag_3In$ and Pb were revealed on it at the solder alloy of 3% In addition. The drossability was superior to Sn-37%Pb solder alloy and the solder alloys of 2% In addition was not generated for 3hrs.

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A study on the characteristics of Pb free Sn-2%Ag-x%Bi solder alloys (Pb Free Sn-2%Ag-x%Bi계 Solder의 특성에 관한 연구)

  • 흥순국;박일경;강정윤
    • Journal of Welding and Joining
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    • v.16 no.3
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    • pp.148-156
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    • 1998
  • The purpose of this study is to investigate the characteristics of Pb-Free Sn-2%Ag-Bi solder alloys. The solder alloys used in this study is Sn-2%Ag-(3,5,7,9%) Bi It is examined that their properties such as melting range, wettability, microstructure, microhardness, and tensile property. The addition of Bi(3,5,7,9%) lowered the melting point of the solder and the melting range was 196~203$^{\circ}C$. The wettability of the solder as equal to that of Sn-37% Pb solder. The morphology of structure did not change largely by addition of Bi. But the structure of cellular dendrite of linear type displayed. The tensile strength of the solder was superior to that of Sn-37%Pb solder. But the elongation was inferior to that of Sn-37%Pb solder. The hardness of Sn-2%Ag solder was tow times and that of Sn-2%Ag-Bi solder was three times of that in Sn-37%Pb solder. But the effect of increment of Bi content did not change largely.

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Microstructure Characterization of the Solders Deposited by Thermal Evaporation for Flip Chip Bonding (진공 증발법에 의해 제조된 플립 칩 본딩용 솔더의 미세 구조분석)

  • 이충식;김영호;권오경;한학수;주관종;김동구
    • Journal of the Korean institute of surface engineering
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    • v.28 no.2
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    • pp.67-76
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    • 1995
  • The microstructure of 95wt.%Pb/5wt.%Sn and 63wt.%Sn/37wt.%Pb solders for flip chip bonding process has been characterized. Solders were deposited by thermal evaporation and reflowed in the conventional furnace or by rapid thermal annealing(RTA) process. As-deposited films show columnar structure. The microstructure of furnace cooled 63Sn/37Pb solder shows typical lamellar form, but that of RTA treated solder has the structure showing an uniform dispersion of Pb-rich phase in Sn matrix. The grain size of 95Pb/5Sn solder reflowed in the furnace is about $5\mu\textrm{m}$, but the grain size of RTA treated solder is too small to be observed. The microstructure in 63Sn/37Pb solder bump shows the segregation of Pb phase in the Sn rich matrix regardless of reflowing method. The 63Sn/37Pb solder bump formed by RTA process shows more uniform microstructure. These result are related to the heat dissipation in the solder bump.

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A Study on The Solderability of Micro-BGA of Sn-3.5Ag-0.7Cu (Sn-3.5Ag-0.7Cu Micro-BCA의 Soldering성 연구)

  • ;;;;Kozo Jujimoto
    • Journal of the Microelectronics and Packaging Society
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    • v.7 no.3
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    • pp.55-61
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    • 2000
  • Sn-37Pb and Sn-3.5Ag-0.7Cu solder balls of 0.3 mm diameter were reflow soldered with the variation of soldering peak temperature and conveyer speed of reflow machine. The peak temperatures far soldering were changed in the range of 220~$240^{\circ}C$ for Sn-37Pb and 230~$260^{\circ}C$ for Sn-3.5Ag-0.7Cu. As the results of experiments, optimum soldering condition for Sn-37Pb was $230^{\circ}C$ of soldering temp., 0.7~0.8 m/min of conveyer speed. The optimum condition for the Sn-3.5Ag-0.7Cu was $250^{\circ}C$ and 0.6 m/min. The maximum shear strength for the soldered joints of Sn-37Pb was 555 gf and of Sn-3.5Ag-0.7Cu was 617 gf. Thickness of the intermetallic compound Cu6Sn5 on the soldered interface was 1.13~1.45 $\mu\textrm{m}$ for Sn-37Pb and 2.5~4.3 $\mu\textrm{m}$ for Sn-3.5Ag-0.7Cu.

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Electromigration Behavior in the 63Sn-37Pb Solder Strip (63Sn-37Pb 솔더 스트립에서의 Electromigration 거동)

  • Lim Seung-Hyun;Choi Jae-Hoon;Oh Tae-Sung
    • Journal of the Microelectronics and Packaging Society
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    • v.11 no.2 s.31
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    • pp.53-58
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    • 2004
  • To facilitate the observation of the electromigration of 63Sn-37Pb eutectic solder, strip-type samples were fabricated by solder evaporation. The electromigration test for the 63Sn-37Pb solder strip was conducted at temperatures of $80{\sim}150^{\circ}C$ and the current densities of $1{\times}10^4{\sim}1{\times}10^5\;A/cm^2$. With increasing temperature and the current density, mean-time-to-failure(MTTF) decreased due to the formation of hillock and void in the solder strip. The activation energy for the electromigration in the 63Sn-37Pb solder strip was analyzed as $0.16{\sim}0.5\;eV$ using Black's equation.

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A Study on Characteristics of Sn-37Pb and Sn-4.0Ag-0.5Cu Solder Joints as Various A:V Ratio (A:V Ratio 변화에 따른 Sn-37Pb, Sn-4.0Ag-0.5Cu Solder 접합부의 특성 연구)

  • Han, Hyun-Joo;Lim, Seok-Jun;Moon, Jung-Tak;Lee, Jin
    • Proceedings of the International Microelectronics And Packaging Society Conference
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    • 2001.11a
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    • pp.67-73
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    • 2001
  • To investigate the relationships of solder joint characteristics with solder composition and A:V ratio (solder volume per pad area), Sn-37Pb and Sn-4.0Ag-0.5Cu solder balls with 330, 400, 450 and $457{\mu}{\textrm}{m}$ size were reflowed on same substrate. Sn-37Pb and Sn-4.0Ag-0.5Cu was reflowed at $220^{\circ}C$ and $240^{\circ}C$ respectively by IR-type soldering machine. As a result of reflowed solder- ball diameter(D) and height(H) measurement, D/H was decreased with solder ball size increment in range of 330~450 ${\mu}{\textrm}{m}$. But, D/H was increased in the solder joint for 457 ${\mu}{\textrm}{m}$ size, it was caused possibly by decrement of solder ball height increment compared with solder volume increment. As a result of shear and pull test, joint strength with A:V ratio was high. Joint strength of Sn-4.0Ag-0.5Cu was higher than Sn-37Pb. However, Sn-37Pb had more stable solder joint of small standard deviation. A thick and clean scallop type Ni-Cu-Sn intermetallic compound layer was formed in high A:V ratio and Sn-4.0Ag-0.5Cu solder joint interface.

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Effects of Fatigue Strength by Solder Ball Composition (솔더볼 조성에 의한 피로강도의 영향)

  • 김경수;김진영
    • Journal of the Korean Vacuum Society
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    • v.13 no.3
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    • pp.127-131
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    • 2004
  • Package reliability test was conducted to investigate the effect of solder composition on the ball fatigue strength for BGA (Ball Grid Array) packaging. The test pieces are assembled using eutectic composition 63Sn/37Pb, 62Sn/36Pb/2Ag, and 63Sn/34.4Pb/2Ag/0.5Sb solder after pre-conditioning at MRT Lv 3 (Moisture Resistance Test Level) and then conducted under T/C (Temperature Cycle test). For each case, the ball shear strength was obtained and micro structure photos were taken. SEM (scanning electron microscope) and EDX (Energy Dispersive X-ray) were used to the analyze failure mechanism. The growth rate of Au-Sn intermetallic compound in Sn63Pb34.5Ag2Sb0.5 solder was slow when compared to 63Sn/37Pb solder and 62Sn/36Pb/2Ag solder. The degradation of shear strength of solder balls caused by solder composition was discussed.

Mechanical Reliability Evaluation of Sn-37Pb Solder/Cu and Sn-37Pb Solder/ENIG Joints Using a High Speed Lap-shear Test (고속 전단시험법을 이용한 Sn-37Pb/Cu 와 Sn-37Pb/ENIG 솔더 접합의 기계적신뢰성 평가)

  • Jeon, Seong-Jae;Hyun, Seung-Min;Lee, Hoo-Jeong;Lee, Hak-Joo
    • Proceedings of the KSME Conference
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    • 2008.11a
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    • pp.250-255
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    • 2008
  • This study utilized a high speed lap-shear test to evaluate the mechanical behavior of Sn-37Pb/Cu and Sn-37Pb/Electroless Nickel immersion Gold under bump metallization solder joints under high speed loading and hence the drop reliability. The samples were aged for 120 h at different temperatures ($120^{\circ}C,\;150^{\circ}C,\;170^{\circ}C$) and afterward tested at different displacement rates (0.01 mm/s to 500 mm/s) to examine the effects of aging on the drop life reliability. The combination of the stress-strain graphs captured from the shear tests and identifying a fracture mode dominant in the samples for different strain rates leads us to conclude that the drop reliability of solder joints degrades as the aging temperature increases, possibly due to the role of the IMC layer. This study successfully demonstrates that the analysis based on a high speed lap-shear test could be critically used to evaluate the drop reliability of solder joints.

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In-situ Analysis of Temperatures Effect on Electromigration-induced Diffusion Element in Eutectic SnPb Solder Line (공정조성 SnPb 솔더 라인의 온도에 따른 Electromigration 확산원소의 In-situ 분석)

  • Kim Oh-Han;Yoon Min-Seung;Joo Young-Chang;Park Young-Bae
    • Journal of the Microelectronics and Packaging Society
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    • v.13 no.1 s.38
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    • pp.7-15
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    • 2006
  • In-situ observation of electromigration in thin film pattern of 63Sn-37Pb solder was performed using a scanning electron microscope system. The 63Sn-37Pb solder had the incubation stage of electromigration for edge movement when the current density of $6.0{\times}10^{4}A/cm^2$ was applied the temperature between $90^{\circ}C\;and\;110^{\circ}C$. The major diffusion elements due to electromigration were Pb and Sn at temperatures of $90-110^{\circ}C\;and\;25-50^{\circ}C$, respectively, while no major diffusion of any element due to electromigration was detected when the test temperature was $70^{\circ}C$. The reason was that both the elements of Sn and Pb were migrated simultaneously under such a stress condition. The existence of the incubation stage was observed due to Pb migration before Sn migration at $90-110^{\circ}C$. Electromigration behavior of 63Sn-37Pb solder had an incubation time in common for edge drift and void nucleation, which seemed to be related the lifetime of flip chip solder bump. Diffusivity with $Z^*$(effective charges number) of Pb and Sn were strongly affect the electromigration-induced major diffusion element in SnPb solder by temperature, respectively.

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