Related Papers
Recent Advances in Flip-Chip Underfill: Materials, Process, and Reliability
Carem Coelho
—In order to enhance the reliability of a flip-chip on organic board package, underfill is usually used to redistribute the thermomechanical stress created by the coefficient of thermal expansion (CTE) mismatch between the silicon chip and organic sub-strate. However, the conventional underfill relies on the capillary flow of the underfill resin and has many disadvantages. In order to overcome these disadvantages, many variations have been invented to improve the flip-chip underfill process. This paper reviews the recent advances in the material design, process development, and reliability issues of flip-chip underfill, especially in no-flow under-fill, molded underfill, and wafer-level underfill. The relationship between the materials, process, and reliability in these packages is discussed.
IEEE Transactions on Electronics Packaging Manufacturing
Corner bonding of CSPs: processing and reliability
2000 •
Pradeep Lall
Comparison of Thermal Fatigue Performance of SAC105 (Sn-1.0Ag-0.5Cu), Sn- 3.5Ag, and SAC305 (Sn-3.0Ag-0.5Cu) BGA Components with SAC305 Solder Paste
Donald Blanchet
Many BGA and CSP component suppliers have begun shipment of components with a variety of " second generation " Pb-free solder ball alloys. Much of the motivation for the alloy changes has been to improve mechanical shock resistance. Several publications have established the improved performance of such 2 nd level BGA/CSP sphere alloys; however, much less has been published regarding the thermal fatigue resistance of components with these new Pb-free ball alloys. As these components and alloys become mainstream, their use in situations where thermal fatigue resistance is critical to product life will become an important consideration. Therefore, an understanding of thermal fatigue performance for new alloys is necessary for OEM/ EMS/ ODM companies to make design and procurement decisions, and for component suppliers to ensure the reliability of their products under a range of field use conditions. In this study, the thermal fatigue performance under accelerated test conditions is compared for three common BGA ball alloys: SAC105, Sn-3.5Ag, and SAC305 as a control. Accelerated thermal cycle (ATC) testing was performed using 676 PBGA components with 1.0 mm pitch and electrolytic Ni/Au finished component pads. These components were assembled to high-temperature rated Cu-OSP coated printed circuit boards using SAC 305 solder paste, which represents one of the most common assembly practices in industry today. ATC testing was performed using the IPC-9701A TC1 condition of 0/100°C with 10-minute dwells (nominal); 3 different failure criteria were used in constructing the Weibull failure curves. The data indicate that SAC105 has the lowest thermal fatigue resistance among the alloys tested, with Sn-3.5Ag and SAC 305 having similar and superior performance. The impact of failure criterion on the Weibull curves is also presented. The implications of these findings and areas for further study are discussed. Introduction Several publications [1-7] have demonstrated improved mechanical shock fracture resistance for a variety of " second generation " Pb-free solder ball alloys. A number of BGA/CSP component suppliers are now shipping devices that use these new solder alloys. However, iNEMI has identified the thermal fatigue resistance of the new Pb-free ball alloys to be a major knowledge gap [8, 9]. In situations where thermal fatigue resistance is critical to product life, this knowledge gap creates a significant risk. One example is in memory devices, where low-Ag alloys are being introduced by some suppliers. As such devices begin use in the next generation Pb-free servers; thermal fatigue resistance is likely to be a concern due to their relatively large die and the demanding thermal environment. Therefore, an understanding of thermal fatigue performance for new alloys is necessary for OEMs to make design and procurement decisions, and for component suppliers to ensure the reliability of their products over a range of field use conditions.
Proceedings - Electronic Components and Technology Conference
A Component Level Test Method for Evaluating the Resistance of Pb-free BGA Solder Joints to Brittle Fracture under Shock Impact
R. Rajoo
A high-speed shear tester has been used to evaluate the interface strength of Pb-free solder balls with varying Ag and Cu content to a BGA laminate interposer with different finishes. The shear rate used is 0.45 m/s. Components with SAC405 and SnPb solder balls have been used as a reference. Results are compared with SAC305, SAC305 with NiGe addition, Castin 258 (2.5Ag-0.8Cu-0.5Sb), SAC105 (1.0Ag-0.5Ag), SAC101 (1.0Ag-0.1Cu-0.02Ni-xIn), SACX (0.3Ag-0.7Cu-0.1Bi), LF35 (1.2Ag-0.5Cu) and Sn3.5Ag. Electroplated NiAu finishes on the BGA laminate interposer studied come from different suppliers. Three failure modes are observed in the high speed shear test: brittle fracture in the intermetallic layer at the ball/interposer interface, ductile fracture in the solder bump and peel off of the solder pad from the interposer. Analysis of the fracture interface shows that almost all Pb-free solder alloys fail either in the intermetallic layer or by pad peel off. Only SAC101 and Sn3.5Ag show duct...
2007 Proceedings 57th Electronic Components and Technology Conference
2007 •
Se-Woong Cha
IEEE Transactions on Components, Packaging and Manufacturing Technology
Underfill Selection, Characterization, and Reliability Study for Fine-Pitch, Large Die Cu/Low-K Flip Chip Package
2011 •
xiaowu zhang
Microelectronics Reliability
No-flow underfill flip chip assembly––an experimental and modeling analysis
2002 •
Stoyan Stoyanov
Electronic Components and Technology Conference
UltraHigh Reliability Flip Chip on Laminate For Harsh Environments
2005 •
Pradeep Lall
In this work, we report on our efforts to develop ultra-high reliability flip chip on laminate assemblies for deployment in harsh thermal cycling environments characteristic of ground and aerospace vehicles (e.g. -55 to 150 degC). Reliability enhancement has been achieved through the use of a novel low expansion, high stiffness, and relatively low cost laminate substrate material that virtually eliminates
FP5-CSG-IMECAT: Highlights of a EC funded Project on Lead-Free Materials and Assembly Development Technologie
2009 •
Mario GOnzalez, Jan Vanfleteren
2010 Proceedings 60th Electronic Components and Technology Conference (ECTC)
Sensitivity analysis of Pb free reflow profile parameters toward flip chip on silicon assembly yield, reliability and intermetallic compound characteristics
2010 •
John Evans
