Analysis of Solder Wetting in Sn-Ag-Cu.05 Lead Free Alloy

2006 ◽  
Author(s):  
Scott J. Anson ◽  
Jacob G. Slezak ◽  
Krishnaswami Srihari
Keyword(s):  
European Union ◽  
Manufacturing Systems ◽  
Manufacturing Industry ◽  
Peak Temperature ◽  
Lead Free ◽  
Electronics Manufacturing ◽  
The European Union ◽  
Reflow Time ◽  
Moisture Sensitivity ◽  
Wetted Area

Lead free electronics soldering is driven by a combination of health and environmental concerns, international legislation and marketing pressure by lead free electronics manufacturing competitors. Since July 1, 2006 companies that do not comply with the European Union legislation are not able to sell circuit assemblies with lead solder in the European Union. China has developed its own regulations, based on the European Union documents with a compliance date of March 1, 2007. Lead free soldering requires an increase in reflow peak temperatures which will further aggravate component moisture sensitivity risks and thereby decrease assembly yield. Prior research has revealed a counterintuitive enhanced solder spreading phenomena at lower peak temperature and shorter time above liquidus with 63Sn/37Pb solder. This present study investigated solder wetting reactions in 96.5Sn/3.0Ag/.5Cu (WT%) (SAC305) using materials and manufacturing systems that are relevant to the electronics manufacturing industry. The objective was to advance the knowledge base of metal wetting such that solder joints can be effectively produced while avoiding heating the assembly any hotter then necessary for effective soldering, which would increase the risk of component damage due to rapid moisture outgassing and associated popcorn delamination. A classical design of experiments (DOE) approach was used with wetted area as the response variable. Additional sample characterization will be conducted outside of the DOE. The samples will be analyzed for correlation of reflow peak temperature, reflow time above liquidus, and wetted area. The expected results are 1) improved understanding of SAC lead free solder wetting reactions, 2) reduced SAC reflow peak temperatures, and thereby reduced risk of moisture sensitivity damage to components.

Russian Manufacturing Industry in the Mirror of its Exports to the European Union

2008 ◽  
Vol 11 (3) ◽  
pp. 31-43
Author(s):  
Karoly Attila Soos ◽  
Ekaterina Ivleva ◽  
Irina Levina
Keyword(s):  
European Union ◽  
Manufacturing Industry ◽  
The European Union

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.

The Role of Pb Impurity in SAC Solder Alloy

2013 ◽  
Vol 752 ◽  
pp. 42-47
Author(s):  
Gréta Gergely ◽  
Alíz Molnár ◽  
Zoltán Gácsi
Keyword(s):  
European Union ◽  
Intermetallic Compounds ◽  
Solder Alloy ◽  
Hazardous Substances ◽  
Lead Free ◽  
Lead Free Solder ◽  
The European Union ◽  
Free Solder ◽  
Sac Solder

The European Union and Japan initiated the issue of RoHS, the directive about the restriction of hazardous substances, which prohibits certain hazardous substances in electronic equipment - including lead - application. Due to the directive the use of lead free solder alloys is spreaded, however the Pb in the form of contamination may be appear under technological process. The lead impurity has significant effect on microstrucutre and lifetime so it is necessary to carry out detailed examinations. In this paper the study of intermetallic compounds in six-element, Pb impured, thermal cycles test-subjected, Sn-Ag-Cu (SAC) solder alloy is demonstrated

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