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- Andersson, Cristina, 1969, et al.
(författare)
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Effect of different temperature cycle profiles on the crack propagation and microstructural evolution of Sn-3.8Ag-0.7Cu solder joints
- 2005
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Ingår i: 15th European Microelectronics and Packaging Conference and Exhibition, EMPC 2005 - Conference Programme and Proceedings. ; 2005, s. 523-528
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Konferensbidrag (refereegranskat)abstract
- Temperature cycling of real electronic components was carried out in a systematic manner at two different temperature profiles and in a single-chamber Heraeus climate cabinet. The first temperature profile ranged between -55°C and 100°C and the second between 0°C and 100°C. Top-side SMD components (chip resistors and Ball Grid Arrays (BGA)) were soldered with Sn-3.8Ag-0.7Cu lead free solder paste. Crack initiation and propagation was analyzed after every 500 cycles for each temperature cycling profile. Totally, 6500 cycles were run at both temperature profiles. Finite element modeling (FEM) calculations, for the analysis of strain and stress of 1206 chip joints were used to corroborate the experimental work results, especially regarding the crack initiation sites. Cracks were firstly visible for the temperature cycling ranging between -55°C and 100°C. The cracks observed were also visibly smaller for the temperature profile ranging between 0°C and 100°C, concluding that crack initiation and propagation was slightly slower for this temperature profile. Cracks continued to propagate as a function of temperature cycles. The reason for this difference in crack initiation and propagation was also analyzed.
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| 5. |
- Andersson, Cristina, 1969, et al.
(författare)
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Characterization of Mechanical Properties of Eutectic Sn-Co-Cu Lead Free Alloy
- 2006
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Ingår i: Proceedings of the 1st IEEE CPMT Electronics Systemintegration Technology Conference (ESTC2006), September 5-7, 2006, Dresden, Germany. - 9781424405527 ; 1, s. 152-160
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Konferensbidrag (refereegranskat)abstract
- The Sn-Co-Cu eutectic solder alloy is a less expensive and is therefore a possible alternative to the Sn-Ag-Cu alloys. The Sn-Co-Cu system eutectic composition was obtained by means of CALPHAD (CALculation of PHAse Diagram) methodology. The composition of the Sn-rich, eutectic Sn-Co-Cu system was found to be 0.4%Co and 0.7%Cu (wt%) with a melting point of 224°C. The tensile behavior of the eutectic Sn-0.4Co-0.7Cu bulk samples was studied under three different conditions of strain rates (10 -6 , 10 -4 and 10 -3 /s) and compared to both Sn-37Pb and Sn-4.0Ag-0.5Cu alloys. The evaluation of the tensile results showed that the effect of strain rate played an important roll on the tensile properties of these alloys, and it is clearly observed that the tensile strength increases as the strain rate increases. Furthermore, Sn-4.0Ag-0.5Cu alloy shows better Ultimate Tensile Strength (UTS) followed by Sn-37P and Sn-0.4Co-0.7Cu system. © 2006 IEEE.
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| 6. |
- Andersson, Cristina, 1969
(författare)
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Lead-free soldering assessment using different board finishes
- 2005
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Ingår i: New Exploratory Technologies 2005.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- A lead-free surface mounting process was assessed and compared to a conventional leaded one. The ternary lead-free Sn-3.0Ag-0.5Cu solder paste was compared to Sn-36Pb-2Ag. Two different board finishes were used, the first one being a lead-free Matte tin (100% Sn) and the second a Sn-37Pb. The boards were aged in a pressure cooker under the influence of 103ºC, 100% RH for a time period of 30 days. The shear strength of some solder joints was measured as a function of aging and production parameters used. The void content was analysed as a function of board metallization, solder paste used and component pitch (large and small pitch). The solderability results were also analysed, where factors such as wetting, solder balls, bridges, and solder joint shape were compared.The results show that Matte tin is the preferred board finish when using the lead free solder paste. This is based on the fact that the combination lead-free solder and Matte tin resulted in much lower void content compared to the combination lead-free solder and Sn-37Pb metallization. The shear test results show that the un-aged boards attained a higher shear strength compared to the aged ones. Two failure modes were however observed during the shear testing. The majority of the aged samples showed complete pad lift-off while un-aged samples showed a fracture through the solder joint. Regarding the solderability results, the lead free process depicted comparable quality to the leaded process.
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| 7. |
- Andersson, Cristina, 1969, et al.
(författare)
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Low Cycle Fatigue Behavior of Sn-4.0Ag-0.5Cu Lead-free in Corrosive Environmental Conditions
- 2006
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Ingår i: ESTC 2006 - 1st Electronics Systemintegration Technology Conference; Dresden, Saxony; Germany; 5 September 2006 through 7 September 2006. - 9781424405527 ; 1, s. 457-467
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Konferensbidrag (refereegranskat)abstract
- Isothermal low cycle fatigue experiments of lead free Sn-Ag-Cu solder joints were executed in different corrosive environmental conditions. The environments/factors varied were temperature, humidity and salt application on to the solder joints. The experiments were executed according to a full factorial design of experiments where the three different factors and two levels for each factor were varied according to literature. The outcome of the design of experiments was the number of cycles to failure defined as 50% load drop. The main goal with this work was to analyze the fatigue behavior of this solder material as a function of the different corrosive environments, and simultaneously to analyze its corrosion behavior/resistance. The factor with the highest effect on the fatigue life was salt application followed by temperature. The factor humidity was not significant for the tests performed.
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- Andersson, Cristina, 1969, et al.
(författare)
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Low Cycle fatigue of lead-free solders
- 2001
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Ingår i: The Fourth International Symposium on Electronic Packaging Technology. ; , s. 462-470
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Konferensbidrag (refereegranskat)
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