The Influence of Intermetallic Compounds, (IMC), on High Speed Shear Testing with a Specific Interest in Electroless Palladium / Autocatalytic Gold

2017 ◽  
Vol 2017 (DPC) ◽  
pp. 1-43
Author(s):  
Richard John Nichols
Keyword(s):  
Solder Joint ◽  
High Speed ◽  
Electroless Nickel ◽  
Lead Free ◽  
Base Line ◽  
Solder Joint Reliability ◽  
Surface Protection ◽  
Joint Reliability ◽  
Solder Balls ◽  
Joint Integrity

Increasing IO counts have led to ever increasing solder performance expectations. A predominant measure of solder joint integrity is gained through HSS testing. This article will statistically evaluate the solderability of final finishes after substrate and IMC ageing. Lead free solder balls will be used in this exercise to simulate lead free production. The finishes selected are: Immersion tin, Organic Surface Protection (OSP), Electroless Nickel/ Immersion Gold (ENIG), Electroless Nickel /Electroless Palladium and Immersion Gold (ENEPIG) and Electroless Palladium / semi Autocatalytic Gold (EPAG). Where necessary, the adaptions of the final finishes will be included for testing. An example of this is ENEPIG with thin nickel. This is a measure to enable high frequency and or improve flexibility. For the purpose of the paper, the evaluation will endeavor to relate HSS performance and physical and chemical characteristics of the related deposit layer. To ensure that a comparative analysis is possible, an “as received” (ASR) population will be used as a base line. This fully data driven evaluation will aim to increase the understanding of key indicators that can ensure good quality soldering performance. In the field, there are assertions that the IMC is a good indicator of the solder joint integrity. However this is usually as far as this particular statement is taken. A key question that is still outstanding is what particular attribute of the IMC is important for solder joint reliability. The shape and size of the IMC is often cited as crucial to quality assurance. Such indicators may be valid but this study will couple this kind of observation with elemental quantification (EDX), high resolution microscopy and finally mechanical failure techniques. A comprehensive test plan will be executed to more fully understand the role of IMC formation in terms of solder joint reliability, (SJR).

Solder Joint Reliability Improvement Using the Cold Ball Pull Metrology

2005 ◽  
Author(s):  
George F. Raiser ◽  
Dudi Amir
Keyword(s):  
Solder Joint ◽  
Electroless Nickel ◽  
Lead Free ◽  
Attractive Alternative ◽  
Lead Free Solder ◽  
Solder Joint Reliability ◽  
Solder Interconnect ◽  
Joint Reliability ◽  
Test Conditions ◽  
Free Solder

The various methods for improvement of package solder joint reliability (SJR) have centered on the broad categories of (i) reductions in the thermomechanical and mechanical stresses and strains applied to the joints, and (ii) strengthening of the solder interconnect interfaces and materials themselves. In practice, the success of the former depends first and foremost on the latter — an adequate and consistent interconnect ‘strength’ during the package development and production cycles. With the advancement of various pad-plating technologies (most notably ENIG – Electroless Nickel Immersion Gold), sphere chemistries, fluxes and processing conditions, each with their own stability issues, the interconnect strengths can easily undergo seemingly random drifts over time. The Dage™ Cold Ball Pull (CBP) technique, however, has emerged as an attractive alternative to the traditional ball-shear metrology as an interconnect strength monitor. The open issues preventing its adoption are related to identifying the best test conditions (e.g. aging time, pull speed, jaw pressure, etc...), all of which are addressed here. After identifying the best test conditions, we present a number of experimental results that highlight the powerful capability of this tool for optimizing and monitoring solder-joint strength. A full metrology characterization to demonstrate accuracy, repeatability and reproducibility has been performed. Moreover, interesting results have been obtained with respect to solder-aging, multiple-reflow, and time-above-liquidus effects on interconnect strength. Examples of direct correlation between CBP measurements and solder-joint shock performance are demonstrated. CBP is also shown to correlate well to other strength metrologies, such as three-point bend. Finally, CBP is used here to show how to strengthen interconnects by the proper selection of pad plating chemistries, sphere compositions, fluxes, reflow conditions, etc… Maintaining those strengths through development and production can be handled effectively using CBP as a monitor. Looking forward, CBP data presented here shows that certain material and processing choices can maximize lead-free solder interconnect strength and lead-free solder joint reliability.

An Experimental Study on Voids in Mixed Alloy Assemblies

2006 ◽  
Author(s):  
Felix Bruno ◽  
Purushothaman Damodaran ◽  
Krishnaswami Srihari ◽  
Guhan Subbarayan
Keyword(s):  
Solder Joint ◽  
Manufacturing Industry ◽  
Research Effort ◽  
Lead Free ◽  
Process Window ◽  
Electronics Manufacturing ◽  
Solder Joint Reliability ◽  
Process Step ◽  
Joint Reliability ◽  
Robust Process

The electronics manufacturing industry is gradually migrating towards to a lead-free environment. During this transition, there will be a period where lead-free materials will need to coexist with those containing lead on the same assembly. The use of tin-lead solder with lead-free parts and lead-free solder with components containing lead can hardly be avoided. If it can be shown that lead-free Ball Grid Arrays (BGAs) can be successfully assembled with tin-lead solder while concurrently obtaining more than adequate solder joint reliability, then the Original Equipment Manufacturers (OEMs) will accept lead-free components regardless of the attachment process or material used. Consequently, the Electronics Manufacturing Service (EMS) providers need not carry both the leaded and the unleaded version of a component. Solder voids are the holes and recesses that occur in the joints. Some say the presence of voids is expected to affect the mechanical properties of a joint and reduce strength, ductility, creep, and fatigue life. Some believe that it may slow down crack propagation by forcing a re-initiation of the crack. Consequently, it has the ability to stop a crack. The primary objective of this research effort is to develop a robust process for mixed alloy assemblies such that the occurrence of voids is minimized. Since there is no recipe currently available for mixed alloy assemblies, this research will study and 'optimize' each assembly process step. The difference between the melting points of lead-free (217°C) and tin-lead (183°C) solder alloys is the most important constraint in a mixed alloy assembly. The effect of voids on solder joint reliability in tin-lead assembly is well documented. However, its effect on lead-free and mixed alloy assemblies has not received due attention. The secondary objective of this endeavor is to determine the percentage of voids observed in mixed alloy assemblies and compare the results to both tin-lead and lead-free assemblies. The effect of surface finish, solder volume, reflow profile parameters, and component pitch on the formation of voids is studied across different assemblies. A designed experiments approach is followed to develop a robust process window for mixed alloy assemblies. Reliability studies are also conducted to understand the effect of voids on solder joint failures when subjected to accelerated testing conditions.

Research Advances of Composite Solder Material Fabricated via Powder Metallurgy Route

2012 ◽  
Vol 626 ◽  
pp. 791-796 ◽  
Author(s):  
Mohd Arif Anuar Mohd Salleh ◽  
Muhammad Hafiz Hazizi ◽  
Mohd Mustafa Al Bakri Abdullah ◽  
N.Z. Noriman ◽  
Ramani Mayapan ◽  
...  
Keyword(s):  
Elevated Temperature ◽  
Powder Metallurgy ◽  
Solder Joint ◽  
Composite Solder ◽  
Lead Free ◽  
Mixed Powder ◽  
Solder Joint Reliability ◽  
Solder Material ◽  
Joint Reliability ◽  
Powder Metallurgy Route

Researches and studies on composite solder have been done by many researchers in an effort to develop viable lead-free solders which can replace the conventional lead-based solders as lead is considered as toxic. Solder materials developed by composite approach showed improvement in their properties and importantly it improved their service performance when compared with solder materials developed by other methods. This paper reviews the solder properties of various types of composite lead-free solder that were fabricated via powder metallurgy route. The fabrication processes of the composite solder material by using powder metallurgy route which involved mixing the powder homogeneously, compaction of the mixed powder and sintering the green body were discussed in detail. The types of reinforcements used in order to enhance its properties and the roles of the reinforcement used were also discussed in detail. Properties of a desirable composite solder and the effects of the reinforcement addition to the composite solder microstructure, changes in its wettability and improvement of its mechanical properties were later discussed in this paper. In conclusion, by reviewing various research advances in composite solder material, a solder material with high solder joint reliability at elevated temperature have yet to be found. Thus, a novel composite solder material with higher solder joint reliability at room and elevated temperature was proposed.

Sign in / Sign up

Export Citation Format

Share Document