Flextronics, Jabil, Celestica, Others Present Business outlooks

Surface Mount Technology: "The tone from all presenters — component distributors, EMS providers, etc. — was decidedly upbeat, though not giddy. Booking trends are up.

Most do not see any impact from the recent macroeconomic issues in Europe. All seven presenting companies indicated the European macro-economic issues have caused no change in customer behavior with regard to order or forecasting patterns"

While the distributors see lead times as stable, EMS companies see them as increasing. The only component manufacturer presenting said lead-times were reasonable.

Component shortages abound. Most of the presenting companies are experiencing component or other supply shortages, and expect these to continue throughout the remainder of 2010.

While the demand environment appears robust across the supply chain, and even as there are some signs of late-cycle behavior (high book/bill, shortages, and certain double-ordering), Credit Suisse believes the limited supply growth will delay any over-supply situation for at least a few more quarters.

Materials Declaration for China RoHS catalogue

Regarding to the China RoHs which has been paid much attention to, Mr Huang from Ministry of National Energy Saving and Comprehensive Utilization Engineering Division revealed in the meeting on May 20 that Telephone, mobile telecommunication set and printing machine will be the first into the control catalog, with Medical Electronics and others to be next. All the listed products shall go under the CCC certification before going to Market. The manufacturers will “trust on” and “rely on” the material declaration from their suppliers, which also places more responsibility on suppliers.

Now IPC and its leading members have updated the IPC 1751 and IPC 1752 standards to be even better. The new standard includes support for the declaration of multiple parts; electronic signature, and support for new and future regulations including China RoHS. Additionally, the 1756 declaration has been created to support an expanded set of manufacturing information over what was originally contained in IPC 1752.

To help the industry better coping with RoHS and REACH, and get good prepared for the upcoming China RoHS. IPC China is going to hold a 175X Workshop in Shanghai this July. This class will provide an overview of the IPC 175x series along with a demo and hands on experience with the free NIST Scriba data entry software for 175x. Students will learn about the structure of the IPC 175x standard and then have a chance to create actual request and response files using Scriba.

Venue: Shanghai, China

Date: 29-30, July 2010 (1 and half day)

Charges: RMB 1000 for members and RMB 1500 for non-members.

Draft Indian WEEE (RoHS?) proposals

Directive Decoder) "The Indian Government has published proposals for the disposal of WEEE (Waste Electrical and Electronic Equipment). The draft also includes what is referred to as the reduction in the use of hazardous substances. This could well be a reference to RoHS although further clarity is required.

The draft does not say if the 20 substances listed, with concentration limits are restricted or that manufacturers should avoid the use of them.

It is unclear whether the thresholds refer to the concentrations in the finished product, in homogeneous materials or something else (remember the debate around this subject leading up to the implementation of EU RoHS).

There are no exemptions associated with the draft but the scope proposed is similar to EU WEEE and includes EU categories 8 and 9, medical devices and monitoring and control instruments."

Sony Ericsson, Dell, HP call on EU to ban more substances

EETimes.com: "Sony Ericsson along with other members of the alliance is calling for restrictions on all brominated flame retardants (BFR) as well as polyvinyl chloride (PVC)."

When BFR and PVC are incinerated under substandard recycling conditions, they form halogenated dioxins that are potent toxic chemicals. Over the last 18 months Sony Ericsson has been developing products without these unwanted substances and said that it believes that substitute materials are available and could be rolled out across the industry with little disruption.

"Sony Ericsson is committed to a complete phase-out of halogenated organic substances from its products, and at the current time has phased out almost all brominated flame retardants," said Daniel Paska, environmental expert at Sony Ericsson. "We believe the electronics industry has a responsibility to move proactively to find substitutes to replace BFR and PVC and are therefore calling on EU legislators to show leadership on this issue by voting to tighten the RoHS directive."

Sony Ericsson along with the other members of the alliance will lobby EU legislators who are currently in the process of debating whether to tighten the existing RoHS directive and invites other members of the industry to join them.

GEAMCOSS Project finds no problems for Pb-free Aerospace

Environment - Environmental Technologies Action Plan: "The Green Electronics in Aeronautic and Military Communication Systems LIFE project focused on lead-free assembly of electronic equipment for the aeronautical and military sectors."

Lead soldering has long been a key element in the assembly of electronics equipment. However, the presence of lead makes it difficult to recycle. The transition to lead-free assembly has improved the environmental impact of manufacturing, using and recycling electronic products

Use of lead was banned in most consumer electronics in July 2006, under the Waste Electrical and Electronic Equipment (WEEE) and the Restriction of Hazardous Substances (RoHS) Directives. These EU Directives have had a particular impact on electronic equipment in the aeronautical and military sectors. While lead-free solutions have been found for consumer electronics, these do not meet the specific needs of the aeronautic and defence industries.

These sectors require reliable, secure and maintainable electronics, which perform well under harsh environmental conditions. The Green Electronics in Aeronautic and Military Communication Systems (GEAMCOS) LIFE project set out to develop both an assembly process for current electronic equipment with lead-free soldering, and a fully lead-free assembly process.

GEAMCOS had a total budget of €3.3 million – €1.5 million in LIFE funding. It was led by the European Aeronautic Defence and Space Company (EADS), in partnership with Airbus, ACTIA and Tech CI.

The project found no major difficulties in terms of reliability and compatibility when assembling leaded components with lead-free solder. Test boards were also assembled with a lead-free process – using a tin, silver and copper alloy – and tested to see how the components would cope in harsh environments.

No major issues were encountered when manufacturing the test boards, which all performed well in humidity, thermal cycling and vibration tests. A functioning demonstrator was then constructed using a lead-free process. This lead-free demonstrator met the qualification needs for such a product.

The project concluded that the lead-free assembly of electronic circuits was as reliable as existing lead-based processes. To this end, the organisers expect lead-free assemblies to be used in the aeronautical and military sectors in the future. Through the project, generic guidelines for manufacturers who wish to implement lead-free processes were written.

Since the completion of GEAMCOS in February 2009, many of the EADS company’s products are now assembled using lead-free processes. And project partner Airbus is using some new lead-free electronics boards in its A350 aircraft.

IPC Symposium on Tin Whiskers

IPC Symposium on Tin Whiskers: "Be part of an important event that will explore solutions to a major technical challenge — present your work at the IPC Tin Whiskers International Symposium."

As a speaker, you will be promoted as a subject matter expert in IPC communications distributed to a global audience and to event participants. This is a unique and cost-effective channel for marketing your organization and an opportunity to make a contribution to the industry.

Presentations are sought on the full range of Tin Whiskers theory and practice, in every market sector:

military/aerospace, automotive, telecom and consumer.

Metallic Resources

Metallic Resources: "Metallic Resources' standard bar solder is manufactured from electrolytically processed tin and lead to create solder so pure it far exceeds the most common specification requirements. It is specially designed for use in all wave, dip, and tinning soldering applications and high production rate operations that require consistent and reliable performance."

It is primarily used in printed circuit board assembly operations common to the electronics market. Solder pots using electrolytic solder can be operated at lower temperatures to provid energy savings, extended pot life, reduced thermal stress, and reduced potential of contamination.

Lower viscosity improves the fluidity, which in turn improves the solder's wetting capability as well as reducing necessary rework. The electrolytic manufacturing process assures batch-to-batch consistency for predictable solder performance in the solder pot. The process removes metallic and non-metallic impurities often found in "virgin metals" and reclaimed solders to provide a purer tin/lead solder. This purity results in a smaller crystalline structure which exhibits a shinier, more brilliant solder appearance.

India consults on RoHS rule proposals

Chemical Watch: "Threshold limits for up to 20 substances could be included in national legislation on waste electrical and electronic equipment (WEEE) issued for consultation by India’s Ministry of Environment and Forests (MoEF). The draft rules, issued for a 60-day consultation last week, are closely modelled on the EU WEEE Directive and its sister Directive on the restriction of hazardous substances (RoHS) in such equipment. Rule 15 of the Indian..."

SnCu, SnAg with nano alumina and tin oxide

Factiva: "According to recent research published in the Journal of Materials Engineering and Performance, 'In the present study, Sn-0.7Cu and Sn-3.5Ag lead-free solders used in the electronics packaging industry were reinforced with different volume percentages of nano-size alumina and tin oxide particulates, respectively, to synthesize two new sets of nanocomposites. These composites were developed using microwave-assisted powder metallurgy route followed by extrusion.'

'The effects of addition of particulates on the physical, microstructural, and mechanical properties of the nanocomposites were investigated. Mechanical properties (microhardness, 0.2% YS, and UTS) for both composite systems increase with the presence of particulates. The best tensile strength was realized for composite solders reinforced with 1.5 vol.% alumina and 0.7 vol.% tin oxide particulates, which far exceeds the strength of eutectic Sn-Pb solder,' wrote S.M.L. Nai and colleagues, Singapore National University.

The researchers concluded: 'The morphology of pores was observed to be one of the most dominating factors affecting the strength of materials.'"

Journal of Materials Engineering and Performance, 2010;19(3):335-341).

For additional information, contact S.M.L. Nai, Singapore National University, Minerals Met & Mat Technol Center, 9 Engn Dr 1, Singapore 117576, Singapore.Journal of Materials Engineering and Performance, 2010;19(3):335-341).

For additional information, contact S.M.L. Nai, Singapore National University, Minerals Met & Mat Technol Center, 9 Engn Dr 1, Singapore 117576, Singapore.Journal of Materials Engineering and Performance, 2010;19(3):335-341).

For additional information, contact S.M.L. Nai, Singapore National University, Minerals Met & Mat Technol Center, 9 Engn Dr 1, Singapore 117576, Singapore.

Thales paper on Embedded components

IPC: "The other winning International Paper award went to Arnaud Grivon of Thales Corporate Services, for authoring 'Industrial PCB Development Using Embedded Passive & Active Discrete Chips Focused on Process and DfR.' His co-authors were Michel Brizoux, Dr. W.C. Maia Filho and E. Monier-Vinard, all from Thales Corporate Services, along with Johannes Stahr and Mike Morianz of AT&S Austria Technologie Systemtechnik AG."

Tin plating method to reduce whiskers

US7695605: "1. A method of forming an article comprising:
a) providing a metal alloy substrate;

b) coating the metal alloy substrate with a photoresist;

c) exposing the photoresist to actinic radiation to form a pattern on the photosensitive compound;

d) developing the exposed photoresist to expose a pattern of the metal alloy substrate;

e) etching the exposed metal alloy substrate to a depth of 0.75 microns to 4 microns with a persulfate compound to inhibit whisker formation;

f) stripping remaining photoresist from the metal alloy substrate to form a patterned metal alloy substrate; and

g) depositing a tin or tin alloy coating on the metal alloy substrate to form the article."

Whitlaw, Keith J.; Buxton, United Kingdom

Toben, Michael P.; Smithtown, NY, United States of America

Egli, André; Richterswil, Switzerland

Crosby, Jeffrey N.; Nuneaton, United Kingdom

Robinson, Craig S.; Coventry, United Kingdom

Assignee: Rohm and Haas Electronic Materials LLC, Marlborough, MA, United States of America

other patents from ROHM AND HAAS ELECTRONIC MATERIALS, L.L.C. (841586) (approx. 4)

News, Profiles, Stocks and More about this company

Published / Filed: 2010-04-13 / 2004-05-1

Effect of nano size copper addition on the tensile properties of tin

Scopus: "In the present study, varying volume fraction of nano-size copper (0 vol. %, 0.2 vol. % and 0.35 vol. %) particulates were incorporated into tin using powder metallurgy method with microwave assisted sintering.

Microstructural characterization studies conducted on the extruded samples showed reasonably uniform distribution of secondary phase, near equiaxed grain morphology and the presence of minimal porosity in all cases. Room temperature tensile test results revealed that strength level increases with the addition of nano copper while ductility decreases. An attempt has been made to correlate the effect of copper addition on the tensile properties of tin."

Minimization of tin whisker growth for ultra-low tin whisker applications

Scopus: "However, some high-reliability end users expect component suppliers to meet MWL requirements beyond that of the JEDEC standard, and it is conceivable that further reduction of JEDEC MWL requirements may ultimately be required; MWL requirements of 30 microns, 20 microns or even less is possible in the future.

This paper will discuss several methods for satisfying future ultra-low tin whisker growth requirements. The first method is the development of a new matte tin electroplating chemistry that produces a deposit which exhibits preferred grain morphology.

The second method is the development of a new tin-silver alloy electroplating process which deposits ∼95% tin / 5% silver alloy. Tin whisker results from these deposits obtained from both laboratory and production environments will be provided, as well as discussions on mechanistic explanations for the reduced tin whisker growth observed using these two methods"

NDCEE work on US military lead-free programs

Update abstract

The National Defense Center for Energy and Environment (NDCEE), through the Mission Critical Environment, Safety, and Occupational Health - Technology Transition and Support Program, is demonstrating, validating, and fielding technologies in a joint environment to increase weapon system performance, safety, and readiness in response to lead (Pb)-free electronic equipment entering the Department of Defense (DoD) supply chain.

Specifically, the NDCEE is working to address the DoD’s Pb-free issue through several completed and on-going projects: •Demonstrated and validated X-Ray Fluorescence (XRF) technology at Tobyhanna Army Depot to identify Pb concentrations of solders and electronic finishes. •Developed the Lead-free Surveillance and Analysis System (LSAS) to collect, store, and provide searchable data pertaining to Pb-free electronics entering the DoD supply chain. •Developing a Pb-free Training Course that will be hosted on the Defense Acquisition University (DAU) website and focused on providing Pb-free education and training for Government Program Managers •Evaluating the performance and improved XRF technology software at Fort Rucker to identify specific solder types, not solely the percent concentration of Pb. •Auditing the suppliers of electronic equipment for the Fire Scout Unmanned Aerial Vehicle (UAV) to determine material compliance and obsolescence. •Supporting the development of a Fire Scout Pb-free policy to ensure that the system complies with regulations and directives while meeting performance and mission requirements.

Effect of rare-earth (La, Ce, and Y) additions on the microstructure and mechanical behavior of Sn-3.9Ag-0.7Cu solder alloy

Scopus: "In this article, we report on the microstructure and mechanical properties of Ce- and Y-containing Sn-3.9Ag-0.7Cu solders. The microstructures of both as-processed solder and solder joints containing rare-earth (RE) elements (up to 0.5 wt pct) are more refined compared to conventional Sn-3.9Ag-0.7Cu, with decreases in secondary Sn dendrite size and spacing and a thinner Cu 6Sn5 intermetallic layer at the Cu/solder interface. These results agree well with similar observations seen in La-containing solders reported previously."

Dudek, M.A., Chawla, N.

School of Materials, Fulton School of Engineering, Arizona State University, Tempe, AZ 85287-8706, United States

Effects of reflow atmosphere and flux on Sn whisker growth of Sn-Ag-Cu solders

Scopus: "We evaluated the Sn whisker growth behavior of Sn-Ag-Cu solder fillets on lead frames of quad flat packages (QFPs) upon OSP printed circuit boards that were exposed to 85'C/85% relative humidity (RH) exposure. Three different concentrations of halogen flux for activated Sn-3.0wt%Ag-0.5wt%Cu were used to solder in air and in an inert N2 reflow atmosphere. The lead frames of the QFPs consisted of Sn plated Cu and Fe-42wt%Ni (alloy 42).

Sn whiskers were observed on the surface of the QFP solder fillet joints that were reflowed with halogen containing flux in an air atmosphere. A substantial amount of Sn oxides were formed in those solder fillets while whisker growth and the amount of Sn oxides increased with the halogen content. Sn oxide formation apparently enhanced whisker formation.

The combination of air reflow atmosphere and high halogen flux was the worst combination for solder fillet oxidation resulting in Sn whisker formation regardless of the electrode's lead frame composition of Cu or alloy 42. In contrast, an inert N2 reflow atmosphere obviously prevented Sn whisker formation on Sn-Ag-Cu solder fillets under all conditions used in this work.

Baated, A.a , Kim, K.-S.a , Suganuma, K.a , Huang, S.b , Jurcik, B.b , Nozawa, S.b , Ueshima, M.c

a Institute of Scientific and Industrial Research, Osaka University, Mihogaoka 8-1, Ibaraki, 567-0047, Japan

b Air Liquide Laboratories, 28 Wadai, Tsukuba, 300-4247, Japan

The Small Component Printing Challenge

Surface Mount Technology: "Recently, at SMTA International (SMTAI) 2009 in San Diego, CA, six technical papers were presented in two sessions dealing with this challenge. Session 32 at IPC APEX EXPO 2010, taking place this week April 6-9, has three papers also discussing this subject.

I believe there are two options to resolve the printing challenges: step stencils or reduction of the acceptable area ratio down to the 0.4 range. The step stencil is a brute force solution and has definite limitations, namely the spacing between apertures that lie in the step to apertures that lie out of the step. Using a two-print step stencil, aperture spacing (first print aperture to second print aperture) as low as 0.4 mm (16 mil) has been reported.1 Work continues in several areas to reduce the acceptable area ratio to 0.4. Solder paste materials, special squeegee blade systems, and stencils with special coatings on the aperture walls all have potential to contribute to the final solution."

Global consumption of tin/lead vs lead free Solder

evertiq.com: "Sharon Starr, Director of Market Research at US based electronics industry trade organization IPC, last week held a session at the annual IPC Apex Expo, which Evertiq attended. One of the key topics included the global consumption of tin-lead versus lead free electronics.

The global solder industry has responded rapidly to the demand for lead free solder. Worldwide consumption of lead free solder was by the end of 2009 67%. China is the largest solder consumer in the world, followed by the United States. China is also the largest consumer of lead free solder. 81% of China's total solder consumption is lead free, while 19% still remains leaded.

All Asian countries together consumes in total 76% lead free solder. Japan consumes 76% lead free and Europe consumes 54% lead free solder.

The United States still only consumes 39% lead free solder. One of the main explanations for this is that a large proportion of electronics produced in the US is within the military segment. Lead free solder is less common in this segment."

Growth behavior of Cu6Sn5 at the interface of Sn-2.5Ag-0.7Cu(0.1RE) solder joints for micro-joining

Scopus: "The microstructure of low-Ag-content Sn-2.5Ag-0.7Cu(0.1RE)/Cu solder joint interface and growth behavior of Cu6Sn5 intermetallic compound (IMC) were investigated by XRD, SEM and EDAX.

The results show that the Cu6Sn5 thickness of the solder joint interface is decided by its dissolution and growing during soldering. With the aging time increasing, the Cu6Sn5 morphology of the solder joint interface changed from scallop-like to lamellar; the growth dynamics follows the parabola law and its growth behavior is controlled by diffusion mechanism.

Addition of 0.1% RE (mass fraction) in the Sn-2.5Ag-0.7Cu solder alloy can effectively reduce the growing rate of the solder joint Cu6Sn5 IMC during the soldering and aging period, and change the fracture mechanism of solder joint; therefore the reliability of the solder joint can be greatly improved"

Wang, Y.a b , Zhang, K.a b , Liu, S.a , Zhao, G.a

a Henan University of Science and Technology, Luoyang 471003, China

b Non-Ferrous Materials Science and Processing Technic Key Laboratory of Henan Province, Luoyang 471000, China

Foxconn sees close to 30% growth in March revenues

EMSNow: "Foxconn Electronics (Hon Hai Precision Industry) has announced non-consolidated revenues of NT$156.97 billion (US$4.97 billion) for March 2010, up 29.22% on month and 52.58% on year, with first-quarter revenues growing 49.2% on year to NT$414.77 billion.

Foxconn noted that the growth in March revenues was mainly due to strong demand for consumer electronics and PC products."

SAC-LOW

From AIM

SAC-LOW is a lead-free alloy that contains tin, 0.7% copper, and 0.2% silver. SAC-LOW was developed as a lower cost alternative to traditional tin-silver-copper alloys and as a substitute for lesser performing low cost leadfree alloys.

When used in wave soldering, SAC-LOW offers far superior fluidity as compared to Sn/Cu alloys, resulting in excellent flow. SAC-LOW also produces less dross than other solder alloys, wets well, provides superior joint strength, and offers superior copper dissolution rates.

SAC-LOW is alloyed in the proprietary Electropure™ method that results in a low drossing, high wetting solder. The Electropure™ process reduces suspended oxides in the solder, thus reducing drossing, improving flow and reducing bridging during soldering.

SAC-LOW may be used with most existing equipment, processes, coatings, and flux chemistries. Unlike other

lead-free solder alloys, SAC-LOW is patent-free. The SAC LOW alloy is available in bar and wire solder forms.

Al: 0.005 Au: 0.05 Cd: 0.002 Fe: 0.02

As: 0.03 Bi: 0.10 Zn: 0.003 In: 0.10

SAC-LOW offers superior copper dissolution resistance as compared to other lead-free

Nanoindentation of rare earth-Sn intermetallics in Pb-free solders

Scopus: "Incorporating rare earth (RE) elements into Sn-rich solder often results in the formation of RE-Sn intermetallics, which affect the deformation behavior of the solder. Little information is available on these constituent phases, and even less on their mechanical properties. In this paper, we report on Young's modulus and hardness of LaSn3, CeSn3 and YSn3 intermetallic compounds formed in a Sn-Ag-Cu-2RE alloy, determined using nanoindentation. Nanoindentation on pure Sn was also performed for comparison."

Dudek, M.A., Chawla, N.

School of Materials, Ira A. Fulton School of Engineering, Arizona State University, Tempe, AZ 85287-6106, United States

Creep behavior of SnAgCu solders with rare earth Ce doping

Scopus: "Extensive testing was carried out to study the effects of rare earth Ce doping on the properties of SnAgCu solder alloys. The addition of 0.03% (mass fraction) rare earth Ce into SnAgCu solder may improve its mechanical properties, but slightly lower its melting temperature. The tensile creep behavior of bulk SnAgCuCe solders was reported and compared with SnAgCu solders. It is found that SnAgCuCe solders show higher creep resistance than SnAgCu alloys. Moreover, Dorn model and Garofalo model are successfully used to describe the creep behavior of SnAgCu and SnAgCuCe alloys"

Low temperature solder by quenching

Patent application: "The inventors have focused on a fact that a quenching process can produce an Sn solid solution which cannot exist from the viewpoint of an equilibrium diagram. Specifically, a Sn--Cu based alloy is produced by using metal Cu exhibiting an intermetallic compound Cu.sub.5Sn.sub.5 having a melting point not less than a reflow temperature at a position adjacent to Sn in the equilibrium diagram. In the case of using a method other than the quenching process, this alloy results in a two-phase structure of Sn and a Cu.sub.5Sn.sub.5 intermetallic compound in a ratio according to the equilibrium diagram depending on the Cu content."

However, it has been unexpectedly found that, when an alloy is produced by a quenching process such as an atomizing method or a melt-span method, Cu which should intrinsically form a Cu.sub.6Sn.sub.5 intermetallic compound is forcibly dissolved into the Sn to result in a phase similar to that of Sn as a Sn solid solution and therefore, in the quenched alloy, the amount of the Cu.sub.6Sn.sub.5 intermetallic compound being a high-melting-point phase is significantly reduced as compared to the theoretical amount calculated from the ratio between Sn and Cu in the alloy. In contrast, it has also been found that, since the Sn phase contributing to soldering exists as a Sn solid solution phase, its content is significantly increased as compared to the theoretical amount.

From these findings, the inventors have further found that the alloy produced through the above quenching process is mostly composed of a Sn solid solution phase and, if the alloy in this state is used for soldering as a solder material and is then cooled in a normal way, there is formed a solid state of an alloy that is prepared by using a method other than the quenching process.

This enables soldering on a temperature condition of a relatively low temperature (about 230.degree. C.), and the solder can retain a good solid state even at a high temperature (about 400.degree. C. or more) due to existence of the Cu.sub.6Sn.sub.5 phase.

Inventors: Hiroki Ikeda Katsu Yanagimoto Noriaki Matsubara

Agents: THE WEBB LAW FIRM, P.C.

Assignees: SANYO SPECIAL STEEL CO., LTD.

Origin: PITTSBURGH, PA US

IPC8 Class: AB23K3524FI

USPC Class: 148 22

Patent application number: 20100089498

Interlocking BGA solder interface

Factiva: "'A ball grid array device includes a substrate, further including a first major surface and a second major surface. An array of pads is positioned on one of the first major surface or the second major surface. At least some of the pads include a barrier layer having pores or openings therein. When solder is placed on the pad, the barrier layer forms an intermetallic compound at a rate different from the rate of the intermetallic compound formed between the pad and the solder. The result is a solder ball on a pad that has a first intermetallic compound and a second intermetallic compound"

Co, Ni substitution in Cu6Sn5 IMC

Factiva: "According to recent research from the United States, 'A Cu6Sn5-based intermetallic compound containing a certain amount of Co or Ni is commonly formed at the interface between a Cu substrate and Sn-based solder. The Co or Ni additive is often found to occupy the Cu atom sublattice in the Cu6Sn5 crystal structure.'

'In this paper, a first-principles approach based on density-functional theory is employed to explore the most favorable occupancy sites of Ni and Co dopants in the Cu6Sn5 crystal structure. It is found that, for up to 27.3 at.% concentration, both Ni and Co atoms tend to substitute for Cu in the Cu6Sn5-based structure and form more thermodynamically stable (Cu,Ni)(6)Sn-5 and (Cu,Co)(6)Sn-5 phases. In comparison, Ni is more effective than Co at stabilizing the Cu6Sn5 phase. At a lower concentration level (9.1 at.%), the Ni or Co atoms prefer to occupy the 4e Cu sublattice. At a higher concentration (27.3 at.%), the Ni atoms will likely be located on the 4e 8f2 Cu sublattice. Analysis of density of states (DOS) and partial density of states (PDOS) indicates that hybridization between Ni-d (or Co-d) and Sn-p states plays a dominant role in structural stability,' wrote F. Gao and colleagues."

Effect of Ni on interfacial ractions

Factiva: "'Two sets of Sn-0.7 wt% Cu-xNi solders and Sn-1.0 wt% Cu-xNi solders (x = 0.02, 0.05 and 0.1 wt%) were prepared. that the interfacial reactions are very sensitive to Ni. With increasing Ni addition, the reaction phase grain, Cu6Sn5, becomes larger and its morphology changes from a rod-like shape into a faceted structure. The reaction progressions are accelerated in comparison with those without Ni addition.

The solder spreading effect on the Cu6Sn5 morphology was also investigated. Cu6Sn5 exhibits a gradual change in microstructure from the center to the rim for the case when the solder ball spreads over a Ni substrate. However, the solder does not alter the Cu6Sn5 microstructure while reacting on a small Ni pad without spreading,' wrote C.H. Wang and colleagues"

IEC, IPC highlight inadequacies of traditional test methods for ensuring reliability of lead-free electronic assemblies

EMSNow: "According to the IPC: 'Users who believe that the 'dip-and-look' methodology has a respectable Gauge R&R would be in for an extreme shock. The IPC committees have also voted that no new solderability test methods will be introduced into the standards without a demonstrated, industry acceptable Gauge R&R value.'

'The IEC recommends wetting balance force measurement and globule testing and we are attempting to harmonise standards documents, to provide acceptable Gauge R&R to its defined methodology.'"

Mitusbishi HT SbCuNiIn Sn solder patent

Factiva: "A solder alloy comprises 5-15% by mass Sb, 3-8% by mass Cu, 0.01-0.15% by mass Ni, and 0.5-5% by mass In. The remainder comprises Sn and unavoidable impurities. Thus it is possible to obtain a highly reliable solder alloy and a semiconductor device with which cracking of a semiconductor element is limited and with which, in addition, the crack-resistance of the solder material is improved.'

The invention carries International Patent Publication No. WO/2010/047139 on April 29."

SMTA China Awards from Nepcon China

Surface Mount Technology: "SMTA China presented awards for the best papers/presentations and exhibits at the SMTA China East 2010 Conference Award Presentation Ceremony, held on April 21, 2010 in conjunction with the SMTA China Annual Breakfast Reception during Nepcon China."

Effect of alloying elements on properties and microstructures of SnAgCu solders

Scopus: "Recent years, the SnAgCu family of alloys has been found a widely application as a replacement for the conventional SnPb solders in electronic industry. In order to further enhance the properties of SnAgCu solder alloys, alloying elements such as rare earth, Bi, Sb, Fe, Co, Mn, Ti, In, Ni, Ge and nano-particles were selected by lots of researchers as alloys addition into these alloys.

Rare earth (RE) elements have been called the ''vitamin' of metals, which means that a small amount of RE elements can greatly enhance the properties of metals, such as microstructure refinement, alloying and purification of materials and metamorphosis of inclusions.

In addition, a small amount of Zn addition has the ability to reduce undercooling efficiently and suppress the formation of massive primary Ag3Sn plates, and Bi/Ga has the ability to enhance the wettability of SnAgCu alloys as well as Ni. Moreover, adding Co/Fe/Ge can effectively refine microstructure, modify interfacial Cu-Sn compounds and increase the shear strength of joints with Cu. This paper summarizes the effects of alloying elements on the wettability, mechanical properties, creep behavior and microstructures of SnAgCu lead-free solder alloys."

Gao, L.a , Xue, S.a , Zhang, L.a , Sheng, Z.a , Ji, F.a , Dai, W.a , Yu, S.-l.a b , Zeng, G.a

a College of Materials Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China

b The 14th Research Institute, China Electronics Technology Group Corporation, Nanjing 210013, China

Effects of Ce and Zn additions on the microstructure and mechanical properties of Sn-3Ag-0.5Cu solder joints

Scopus: "It has been reported that the rapid growth of tin whiskers occurring on the surface of rare earth containing solders can be prevented by the addition of 0.5 wt.% Zn into a Sn-3Ag-0.5Cu-0.5Ce alloy.

The present study shows that the tensile strength of Sn-3Ag-0.5Cu-0.5Ce alloy alloyed with Zn increases significantly in comparison to the Zn-free Sn-3Ag-0.5Cu and Sn-3Ag-0.5Cu-0.5Ce solder. Moreover, the growth of intermetallic compounds at the solder/pad interfaces during the thermal aging at 100 'C and 150 'C was inhibited by the Zn addition.

Nevertheless, the excess of Zn addition to 0.5 wt.% causes poor junction in the Sn-3Ag-0.5Cu-0.5Ce packages. An optimized addition amount of Zn in Sn-3Ag-0.5Cu-0.5Ce solders is 0.2 wt.% for both inhibiting the growth of tin whiskers and strengthening the solder joints, although its ductility is still lower than that of the original Sn-3Ag-0.5Cu."

Lin, H.-J.a b , Chuang, T.-H.a

a Institute of Materials Science and Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei 106, Taiwan

b Industrial Technology Research Institute, Mechanical and Systems Research Laboratories, Hsinchu 310, Taiwan

iNEMI Adds Consultant in Japan

EMSNow: "The International Electronics Manufacturing Initiative (iNEMI), an industry-led consortium, today announced that Masahiro Tsuriya has been named an iNEMI consultant to represent the organization in Japan and other parts of Asia. From his base in Tokyo, he will interact with iNEMI member companies in the region as well as prospective members."

Integration of the NIST and SURDAT Databases on Physical Properties of Lead-Free Solder Alloys

SpringerLink: "The electronic SURDAT database published in 2007 (available freely from the website www.imim.pl/english) is being integrated with the NIST database (available freely from www.boulder.nist.gov/div853/lead_free/solders.html) to provide a single source for data on lead-free (Pb-free) soldering alloys. The NIST database was developed to support circuit board designers, and so it is focused primarily on mechanical properties. In contrast, the SURDAT database is focused primarily on thermophysical properties. Together, they will form a much more complete source for the properties of Pb-free solder alloys."