IPC Updates Assembly Standards

EMS007 IPC Updates Assembly Standards: "IPC has updated a pair of joining and assembly standards, making them easier to use and adding information in areas that have evolved. IPC J-STD-001E and IPC-A-610E have also been more closely linked to eliminate differences that could prove costly to users.

The two documents are related, but there are significant differences. IPC-A-610, Acceptability of Electronic Assemblies, is a visual acceptance standard. It has criteria and illustrations to show how connections need to appear after assembly; the illustrations help users understand the written requirements."

India RoHS

Global Product Stewardship Report (Jan. 2011): "In October 2010, India adopted Electronics Waste (Management and Handling) Rules 2010, which benchmark the EU RoHS Directive. The Rules will enter into force on in January 2012. The WEEE Regulation of China will enter into force as of January 2011. For the moment, only five products are regulated such as televisions, refrigerators, washing machines, room air-conditioners, and computers."

Effect of small addition of zinc on creep behavior of tin

Scopus: "Sn-based alloys with high creep resistance are required for soldering applications. This paper describes the effect of solid solution strengthening on the creep resistance of Sn-Zn alloys. The maximum solubility limit of Zn is 0.34 mass% in Sn.

The creep behaviors of Sn, Sn0.1 mass%Zn and Sn-0.4mass%Zn were examined at 298 and 398 K under constant strain rates ranging from 1 10-4 to 1 10-2 s-1. The creep resistance of Sn was improved significantly by the addition of a small amount of Zn owing to the solid solution strengthening. The creep resistance of Sn-0.4mass%Zn was at the same level as that of Sn-37 mass%Pb. We obtained a stress exponent of about 7 and an activation energy of 41-45 kJ/mol. which indicates that the creep behavior was climb-controlled dislocation creep controlled by pipe diffusion.

The finding that a small addition of Zn improves the creep resistance is useful for developing new Pb-free solders."

Conflict free smelter program

ITRI: "Two electronics industry organisations - the Global e-Sustainability Initiative (GeSI) and Electronic Industry Citizenship Coalition (EICC) - have launched their Conflict-Free Smelter (CFS) program, as part of industry's efforts in response to the conflict minerals provisions of the Dodd-Frank Wall Street Reform and Consumer Protection Act of 2010 passed earlier this year. The minerals covered in the law — coltan (columbite-tantalite, a source of tantalum), cassiterite (tin), wolframite (tungsten) and gold — are used in various industrial, consumer and electronics products and the CFS program focuses on tantalum and tin"

SMART Group Webinar Attacks Tin Whiskers

EMS007: "The presentations prompted an energetic question-and-answer session that ran the event well into overtime. There was discussion on the effects of flux residues--do they accelerate whisker growth and does cleaning reduce whisker growth--currently the subject of studies being conducted in the U.S., and the new nickel-cap process being promoted for high-reliability applications and harsh environments was clearly generating considerable interest.

A well-timed initiative by SMART Group, skilfully and seamlessly managed by Bob Willis: Excellent content and a high level of audience response. A great success!"

Effect of strongly oxidizing environment on whisker growth form tin coating

Scopus: "The effect of a strongly oxidizing environment (105C/100%RH) on tin whisker formation has been studied with Ni and Ag underlayered samples between the tin surface coating and the bronze base material of the electronic components leads. Using nickel or silver underlayer between the copper substrate and the tin coating can be useful for preventing whiskers.

The underlayer blocks the formation of Cu6Sn5 intermetallics which is one of the root causes of whisker growth. The silver underlayered samples started extreme whiskering after 2200h; on the Ni underlayered samples only hillocks have been observed. The shape of the whiskers did not resemble to the usually known whisker appearance.

The oxidizing environment creates tin-oxide fast and causes thick layers of SnOx to appear on the surface of the samples and also on the whiskers. This caused the periodic appearance of large amounts of whiskers; but it blocks the length of them. This combined effect results in only large amounts of short whiskers and even causing the thickness of the tin layer to shrink by 80%. The series of tests has also showed that the nickel underlayered samples resisted whiskering better than the silver underlayered samples"

Commodities - EIU's quarterly tin outlook

Factiva: "Cookson Group (UK), the world’s leading producer of solders, has reported that its underlying sales of solders rose by 23% year on year in the first half of 2010 (solder-making is the largest single market for tin, driving over 50% of total demand). Moreover, in its recently released interim management statement, the company commented that the global electronic equipment production market had experienced a strong third quarter. The rise in sales of solders has been driven by higher orders from manufacturers of consumer electronics. For example, global shipments of personal computers were 24% higher in the first six months of 2010 than in the same period of 2009, according to Gartner, a US-based information technology research company. Global shipments of mobile-phone handsets were 13% higher on the same comparison, according to Nokia (Finland). However, it should be recognised that growth rates slowed in the second half of 2010. For example, global shipments of personal computers are expected to have increased by around only 10% in July-December 2010"

Sn coated Cu nanoinks

Factiva: "The deposition of tin-clad nano-size copper particles was carried out by means of ink-jet printing. Curing the particles on Polyimide (PI) turned them into soldered structures using an Nd-YAG laser,' scientists in Hong Kong, People's Republic of China report.

'Area coverage of 55% was achieved for a single-layer print. Subsequent laser sintering increased this value to 95%. A Butanol-based copper ink and an aqueous tin (Sn)-clad Copper (Cu) ink were produced and were ink-jetted in this work. These nano-metallic inks showed excellent suspension stability with particle weight concentrations as high as 5%. The ink components were examined by measuring the particle size distribution in a dispersed condition, and the melting temperature. A piezo ink-jet print head was used to deposit the inks onto a moveable substrate. The thermal effect of the laser irradiation allowed approaching and connecting adjacent particles by melting the particle's tin coating"

Computer Successfully COOKED!

SolderSmoke Daily News!: "Gents, you'll be pleased to learn that this is a SOLDERING problem. Looks like NVIDIA used a bad mixture of soldering types. There is apparently little blobs of solder on the baord, and little blobs of solder on the chip. LOTs of little blobs. Surface Mount to the MAX! But they used two different solders and this causes the connections to fail far more quickly than they should have. Here are the details:
http://s0.2mdn.net/2994486/Polycom_inquirer.html?rfp=http://www.theinquirer.net/inquirer/news/1004378/why-nvidia-chips-defective

Enter the oven solution. The idea is to simply re-heat the chip and make the solder at the connections melt again!"

Matte Tin (Sn) is the Top Lead-Finish Choice as Alternative to Tin-Lead (SnPb)

Electronics Bus: "As RoHS banned the usage of Lead (Pb), now the semiconductor industry is searching and researching for various alternatives to Tin/Lead (SnPb). They could find a lot of alternatives such as Matte Tin, Tin-Bismuth (SnBi), Tin-Copper (SnCu), Tin-Zinc (SnZn), Nickel-Palladium (NiPd), Nickel-Palladium-Gold (NiPdAu), Nickel-Palladium-silver (NiPdAg), Tin-Silver (SnAg), Tin-Indium (SnIn), Tin-Silver-Copper (SnAgCu), etc.

But until now, none of them is proved as true alternative to Tin-Lead (SnPb) in terms of quality, reliability, and cost.

Meanwhile Matte Tin (Sn) has become a popular alternative due to its low cost and huge availability to component manufacturers. In today’s competitive market, the component manufacturers also more interested in using Matte Tin because of its low cost."

Christopher Associates Debuts Koki SB6N58-A730

EMS007: "Christopher Associates announced today the introduction of Koki's SB6N58-A730 low temperature lead-free solder paste. SB6N58-A730 paste has a melting point of 201-210C. The paste also demonstrates extremely high thermal shock durability.

SB6N58-A730 contains 6% Indium while still achieving low structural transformation. Indium additions lower melting points when compared to SnAgCu alloys such as SAC305. This lower reflow temperature is desirable for PCBs."

Japan Solder Makers Accelerate Production Shift to Overseas

Factiva: "Japanese solder makers are shifting production overseas, mainly to China. Tin supply from Indonesia, the largest tin exporter to Japan, is recently tightening. The supply is concerned to tighten more in 2011. Meanwhile, in China where many Japanese solder makers have production sites, supply and demand balance of tin is loosing. The market condition is better for Japanese solder makers.

Assembly product makers have shifted manufacturing bases to overseas. Along the movement, solder is mainly consumed at overseas to bond electronic parts on printed circuit boards. Several years ago, when lead-free solder became adopted widely, lead-free solder was mostly produced in Japan and exported. In recent years, the production has shifted to overseas.

This movement may be accelerated by current tin supply and demand balance. In Japan, tin supply temporarily tightened for April-July 2010 due to export slowdown from Indonesia. The export restarted and the material shortage was relieved."

A reliability study of nanoparticles reinforced composite lead-free solder

Scopus: "This work looks at the development and investigation of a reinforced composite solder with low melting point. The composite solder was prepared by adding Sn-3.0Ag-0.5Cu nanoparticles into Sn-58Bi solder paste. The Sn-3.OAg-0.5Cu nanoparticles were manufactured using a self-developed Consumable-electrode Direct Current Arc (CDCA) technique."

The results of the experiments detailed in this work indicate that the shear strength of the composite solder increased 2 times in comparison to Sn-58Bi. Meanwhile, the thermomechanical fatigue (TMF) resistance of the composite solder with 1 mass% nanoparticles was 16 times stronger than Sn-58Bi and 4 times stronger than Sn-3.0Ag-0.5Cu

Chen, S.a , Zhang, L.a , Liu, J.a b , Gao, Y.c , Zhai, Q.c

a Key Laboratory of Advanced Display and System Applications and SMIT Center, School of Automation and Mechanical Engineering, Shanghai University, No. 149 Yanchang Road, Shanghai 200072, China

b SMIT Center and Bionano Systems Laboratory, Department of Microtechnology and Nanoscience, Chalmers University of Technology, SE-412 96 Goteborg, Sweden

c School of Materials Science and Engineering, Shanghai University, No. 149 Yanchang Road, Shanghai 200072, China

The true cost of your new Christmas laptop? Ask the eastern Congolese

UTV News: "Eastern Congo's hell is an instance of how globalisation generates ungovernable spaces. Where there is a collision of desperate poverty, plentiful guns and a world greedy for natural resources, a brutal chaos results. To combat that, it takes a very tenacious sort of global campaigning – bringing to attention each element of the system and the part it can play in leveraging change – and mercifully, that is what is now finally starting to happen.

guardian.co.uk Guardian News and Media 2010"

Reducing solder paste inspection in surface-mount assembly through Mahalanobis-Taguchi analysis

Scopus: "Increased functional density and reduced input/output (I/O) spacing are the market trends in the electronics manufacturing industry. Industry reports indicate that approximately 50%-70% of soldering defects are attributed to the solder paste printing process for printed circuit board (PCB) assembly. Hence, after the printing process, a solder paste inspection (SPI) system is generally used to examine the amount of solder paste deposition.

Effective selection of components and bonding pads during solder inspection is extremely important in achieving desired process cycle times and ensuring assembly yield. This paper uses the Mahalanobis-Taguchi system to establish a systematic approach to determining guidelines for solder paste inspection. Among a total of 203 bonding pads on the board for a GPS product, the optimal model suggests that the solder deposition of 121 bonding pads be inspected. The reduction ratio is 40.4%, and the feasibility of the proposed model is verified.

Also, for those bonding pads to be inspected for their solder paste deposition, this study uses empirical data to define the specifications to effectively distinguish acceptable PCB samples from defective. The threshold is within the 100% capability for judgment of solder paste printing quality in the surface mount assembly proces"

Testing Bga Solder Joints by Localized Pulsed-Heat Thermography

Factiva: "A pulse of heat or cold is applied and conducted transversely through a ball grid array device and a printed circuit board via a selected one of the solder joints between them. Heat diffused through the other solder joints is neutralized by a thermal bias shield. The shield is then removed and a thermographic image of the printed circuit board is taken. The process is repeated for each solder joint, and the images are compared to identify defective solder joints"

Nihon Superior Recognized for Achievement in Intellectual Property

EMSNow: "For Nihon Superior, the reasons cited for the award were:

1. The company's prompt response to the EU RoHS Directive on eliminating lead from electronic circuitry that resulted in the granting of patents in 24 countries and regions.

2. Avoiding price competition by the exclusive use of high-quality technology effectively protected by patent and maintaining ongoing activity to strengthen the patent and provide the basis for new patents.

3. Improving global competitiveness by investing in collaborative research at foreign universities.

The use of licensing to ensure fast adoption of the patented technology by overseas companies also was recognized as a key part of Nihon Superior's intellectual property strategy."

Tech firms rapped on conflict minerals

PC Pro: "Technology firms including Toshiba, Panasonic and Canon have been criticised for failing to eliminate so-called 'blood minerals' from their products.

Charity Enough ranked HP top for its work to prevent buying minerals from conflict zones in eastern Congo. Enough said the trade in conflict minerals 'provides the primary fuel for the conflict.'"

Concept for an alternative solder-free flip-chip technique on SOI using black-silicon

Scopus: "Black-Silicon regions are defined on an SOI board and covered with an adhesion layer. The contacts of to be mounted devices are pushed towards these regions, to establish a mechanical, electrical, and thermal contact."

Schnarrenberger, M., Zimmermann, L., Mitze, T., Voigt, K., Bruns, J., Petermann, K.

Technische Universität Berlin, Einsteinufer 25, 10587 Berlin, Germany

Effects of Ni/P/Ce elements on the properties and microstructure of SnAgCu lead-free solders

Scopus: "Effects of trace Ni, P or Ce element additions on the microstructure and the properties of the Sn3.0Ag0.5Cu solder alloy were investigated. Results show that single adding of Ni, P or Ce has little influence on the melting temperature of the Sn3.0Ag0.5Cu solder alloy. P addition can improve the wettability of the solder, i.e. the wetting force of the solder is increased, and the wetting time is decreased.

Single adding of Ni or Ce has no significant effect on the wettability of the soldered alloy and the shear strength of the as-reflowed soldered joint, but can remarkably suppress the decrease of the shear strength of the solder joints due to the high-temperature aging. Besides, P addition significantly increases the oxidation resistance of the soldered alloy, but rare earth Ce addition deteriorates it. The property change of the Sn3.0Ag0.5 solder are attributed to the change of the microstructure caused by trace Ni, P, or rare earth Ce additions"

Dong, W., Shi, Y., Lei, Y., Xia, Z., Guo, F.

Beijing University of Technology, Beijing 100124, China

Study on properties of low-silver lead-free solder alloys with alloy element doping

Scopus: "Low-silver (Ag<1%, mass fraction) SAC lead-free solder alloys meet wettability and reliability problems. Effect of silver content, nickel and bismuth element additions on some key properties such as microstructures, wettability and copper dissolution property of solder alloys was investigated to seek the possible solution.

The results showed that the regular change of microstructures, melting behavior and tensile property of the solder alloys was resulted by the increase of silver content; the additions of bismuth and nickel could improve the solderability (wettability) property of the alloys and lower the copper dissolution rate.

It was also found that the copper dissolution rate of SAC0805BiNi solder is lower than SAC0307 and SAC305 solder alloys, and wettability is close to SAC305 alloy. The alloys with silver content between 0.3% and 1% mass percentages exhibit good ductility. Consequently, the overall performance of low cost solder alloys will be approaching to the SAC305 alloys with proper silver content and addition of alloy elements"

Zhang, Y.-P., Wan, Z.-H., Xu, L., Liu, F.-M., Yang, K.-Z.

Institute of Soldering and Brazing Materials, Guangzhou Research Institute of Non-Ferrous Metal, Guangzhou 510651, China

Research of intermetallic compounds at interface of Sn2.5Ag0.7CuxRE solder joints during aging

Scopus: "The intermetallic compound (IMC) and its growing behavior of Sn2.5Ag0.7CuxRE/Cu solder joint were investigated in the mediator of molybdenum sulfide by means of scanning electronic microscope and X-ray diffraction during aging.

The results show that the Cu6Sn5 morphology of solder joint interface can be changed from initial wavy-like to scallop-like, then to shape-layer.

The thickness of Cu6Sn5 and Cu3Sn IMC at the solder joint interface and the square root of aging time is coincidence with the liner relation, the growing activation energy of Cu6Sn5 is smaller and its coefficient of growth is larger than those of Cu3Sn. The shear strength of the solder joint is the highest with adding 0.1% (mass fraction) RE in the Sn2.5Ag0.7Cu solder alloys, and the Cu6Sn5 and Cu3Sn at solder joint interface have the largest growing activation energy which is separately 81.74 kJ/mol and 92.25 kJ/mol."

Zhang, K.-K.a , Han, L.-J.b , Wang, Y.-L.a , Zhang, X.a , Zhu, Y.-M.a

a School of Materials Science and Engineering, Henan University of Science and Technology, Henan Luoyang 471003, China

b Pinggao Group Co. Ltd., Henan Pingdingshan 467001, China

Influence of Dopant on Growth of Intermetallic Layers in Sn-Ag-Cu Solder Joints

Scopus: "The interfacial interaction between Cu substrates and Sn-3.5Ag-0.7Cu-xSb (x=0, 0.2, 0.5, 0.8, 1.0, 1.5, and 2.0) solder alloys has been investigated under different isothermal aging temperatures of 100C, 150C, and 190C. Scanning electron microscopy (SEM) was used to measure the thickness of the intermetallic compound (IMC) layer and observe the microstructural evolution of the solder joints. The IMC phases were identified by energy-dispersive x-ray spectroscopy (EDX) and x-ray diffractometry (XRD)."

Li, G.Y.a , Bi, X.D.b , Chen, Q.a , Shi, X.Q.c

a School of Electronic and Information Engineering, South China University of Technology, Guangzhou, 510641, China

b Guangdong Yuejing High Technology Co. Ltd., Guangzhou, China

c Materials and Packaging Technologies Group, Hong Kong Applied Science and Technology Research Institute, Hong Kong, China

NEW Events bring National Electronics Week to North Africa

EMSNow: "NEW Events are pleased to announce National Electronics Week North Africa will be taking place on 8 and 9th March, 2011, in Tunisia. The event is being introduced to Tunisia this year and NEW Events is thrilled to be holding the event in such a thriving country.

It is not only a competitive country that continues to attract an increasing number of foreign investors but it is also ranked number 1 for innovation in Africa. North Africa itself is also a hub for electronic manufacturing. With over 120 specific manufacturing companies situated in the country, including names such as, ST Microelectronics, Sagem, Actia, Roal Electronics, Johnson Controls, CIBES Elettronica, Lancorix Electronique, Fuba, Asteel and Siemens. There truly seems to be an ideal fit with the country and NEW.

One Step at a Time on Conflict Minerals

January/February 2011 IPC Review: "On behalf of the industry, IPC submitted comprehensive pre-proposal comments to the SEC in November to help shape practical regulations that can be implemented and that support legitimate mines and activities of the DRC. These recommendations include:

Timing: Because industry efforts are still in their infancy and because the DRC government has shut down access to some mines, it is highly unlikely that a full scale-up of these programs will be possible by the April 2011 deadline. The SEC should use its discretion to implement a phased-in approach to the regulations requiring OEMs to declare whether the minerals used in their products are conflict-free or not."

Is Your Mobile Device or Laptop Funding Conflict Mineral Wars?

TIME.com: "A recent report from Enough Project ranked the top 21 electronics manufacturers, showing their progress in creating products with conflict-free minerals and the steps they've taken to ensure that. Leading the pack was HP with an over 30 percent improvement. The company has endorsed anti-conflict mineral legislation and advocates for strong US regulations for all manufacturers

Apple, who uses tantalum not only in their smartphones but in iPods as well, were given a yellow score, which means there is much room for improvement. (Though several of their top executives have spoken out against conflict mineral mining in the Congo, they did not weigh in on key US conflict mineral legislation.) Toshiba received the worst score of the bunch; they have barely made any changes at all according to the study"

Investigations on melting property, wettability and mechanical property of Sn-XAg-0.5Cu lead-free solder alloys

Scopus: "The melting property, wettability and mechanical property of Sn-XAg-0.5Cu (X=0.1-3.0) lead-free solder alloys were investigated by differential scanning calorimetry (DSC), wetting balance technique, sessile drop method and tensile test. The DSC revealed that the endothermic onset temperature on heating appeared at about 217.3'C for the all solder alloys.

With increasing the Ag content of the solder alloys, the melting temperature ranges of the solders became narrow. It was also shown by the wetting balance and sessile drop experiments that the wettability remarkably increased with the Ag content increased, and then with Ag content farther increased, the wettability were kept constant approximately. The threshold value of the Ag content was 1.0%(mass fraction/%, the same below), which considerably effected on wetting-spreading areas and wetting forces (or wetting time).

Meanwhile, when Ag content is between 0.5% and 3.0%, the specific elongation of solders decreased with the Ag content increased, while the tensile strength and 0.2% yield stresses increased, too."

Wei, G.-Q.a , Wan, Z.-H.a , Zhao, S.-Y.b , Zhang, Y.-P.b , Liu, F.-M.b

a School of Mechanical and Automotive Engineering, South China University of Technology, Guangzhou 510640, China

b Joining Materials Institute, Guangzhou Research Institute of Nonferrous Metals, Guangzhou 510651, China

What nvidia should do now

The Inquirer: "In the end, it comes down to Nvidia screwing up badly on package engineering and testing, then trying as best they can to bury the problem while passing the buck. It appears that every Nvidia 65nm and 55nm part with high lead bumps and/or low Tg underfill are defective, it is just a question of how defective they are, and when they will die.

As far as we are able to tell, contrary to Nvidia's vague statements blaming suppliers, there are no materials defects at work here. Every material they used lived up to the claimed specs, and every material they used would have done the job while kept within the advertised parameters. Nvidia's engineering failures put overdue stress on the parts, and several failures compounded to make two generations of defective parts. The suppliers and subcontractors did exactly what they were told, Nvidia just told them to do the wrong thing."

Lead Free Transition Webcast

DfR Solutions: "This presentation is an introduction to the key aspects in the transition of electronics to lead-free solder, components, PCB laminates and surface finishes and covers the strategies and processes that are integral to a successful transition.

Outline
The Presentation is available for viewing in five parts. Total Running Time: 3 hrs 26 min.

Part 1: Necessary Processes and Documentation, Materials & Component Strategy: Solder Alloys -Running Time: 26 min
Part 2: Materials & Component Strategy: Component Qualification - Running Time: 23 min
Part 3: Materials & Component Strategy: PCB Laminates and Surface Finishes -Running Time: 48 min
Part 4: Assembly Processes -Running Time: 35 min
Part 5: Test and Analysis Strategy, Case Study -Running Time: 74 min"

Handbook of Lead-Free Solder Technology for Microelectronic Assemblies

ASM: "This reference provides a complete discussion of the conversion from standard lead-tin to lead-free solder microelectronic assemblies for low-end and high-end applications. Written by more than 45 world-class researchers and practitioners, the book discusses general reliability issues concerning microelectronic assemblies, as well as factors specific to the tin-rich replacement alloys commonly utilized in lead-free solders. It provides real-world manufacturing accounts of the introduction of reduced-lead and lead-free technology and discusses the functionality and cost effectiveness of alternative solder alloys and non-solder alternatives replacing lead-tin solders in microelectronics"

Tin Pest - A Potential Threat To Technology?

On Point with Ray Mignogna:: "An interesting article by Ronald C Lasky (available online) discusses some of the legends about, and factual episodes of tin pest, and the damage that it can do.

The danger occurs when pure tin is exposed at quite cold temperatures, below about -20 degrees F. These conditions exist in various polar and sub-arctic parts of the globe, and also in outer space. While its unlikely that tin pest will be a problem that most of us will encounter in commercial devices such as computers and cell phones, there exists the potential for this 'disease' to occur in equipment exposed to the low temperature extremes noted above, and could prove damaging to that equipment, including military and space electronics. A growing awareness of the problem by industry will likely lead to the development of new solders with alloying elements other than lead. However, its always good to be aware of the unintended consequences of our efforts to be good environmental stewards by banning lead from products."

SMTA International 2010 Best Papers Announced

EMSNow: "The winner from SMTA International 2010 for Best of Conference is Dave Hillman, Rockwell Collins, for his Lead-Free Symposium presentation entitled 'NASA DoD -55 to 125 Thermal Cycle Test Results.'

Pradeep Lall, Rahul Vaidya, Vikrant More, Auburn University; and Kai Goebel, NASA Ames Research Center, won the Best of Proceedings category for the paper 'Interrogation of Damage-State in Lead-Free Electronics under Sequential Exposure to Thermal Aging and Thermal Cycling.'

Craig Hamilton, John McMahon, Jose Traya, Wang Yong Kang, and Khoo Kok Wei, Celestica Inc.; Matthew Kelly and Marie Cole, IBM Corporation won the Best International Paper category for the paper entitled 'High Complexity Lead-Free Wave and Rework: the Effects of Material, Process and Board Design on Barrel Fill.'"

Webcasts focus on solid state lighting system composition

EETimes: "The inaugural webcasts include simple instructions on how to assemble high power LED lighting, showing that SSL lights can now be easily and quickly constructed using solder-free plug and play parts including the LED’s, connectors, optics and RECOM’s LED drivers."

Properties and microstructure of Sn-0.7Cu-0.05Ni solder bearing rare earth element Pr

Scopus: "Effects of trace amount of rare earth element Pr on properties and microstructure of Sn-0.7Cu-0.05Ni solder were investigated in this paper. The solderability of Sn-Cu-Ni-xPr alloy and shear strengh of Sn-Cu-Ni-xPr soldered micro-joints were determined by means of the wetting balance method and shear test, respectively. Moreover, microstructure of solder alloys bearing Pr, as well as intermetallic compound (IMC) layer formed at solder/Cu interface after soldering were observed. It was concluded that the major benefits of rare earth element Pr on Sn-Cu-Ni lead-free solder are: improving solderability, refining microstructure, and depressing IMC (IMC) growth, which exhibited improved mechanical properties. It also revealed that (Cu,Ni)6Sn5 is the majority IMC phase at the interface of Sn-Cu-Ni-xPr/Cu solder joints. Ni added into the solder effectively suppressed the growth of Cu3Sn and consequently also the total IMC layer thickness. Above all, the thickness and morphology of the interfacial (Cu,Ni)6Sn5 IMC were optimized due to alloying Pr. It can be inferred that Pr and Ni would play an important role in improving the reliability of Sn-Cu-Ni lead-free solder joints"

Zeng, G.a , Xue, S.a , Zhang, L.a , Gao, L.a , Lai, Z.b , Luo, J.a

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

b Provincial Key Lab of Advanced Welding Technology, Jiangsu University of Science and Technology, Zhengjiang, 212003, China

Improvement of flux-less, lead-free solder wettability on CF4-plasma-fluorinated Sn and Ag

Scopus: "Atmospheric pressure non-equilibrium plasma inducted CF4 gas was irradiated to Sn and Ag substrates to obtain fluorinated Sn and Ag surfaces with a high affinity of a lead-free solder without fluxes. The plasma was produced by applying microwave power inducted with Ar-CF4-O2 mixed gases. The plasma irradiation successfully fluorinates the metal surfaces completed within 15min.

The fluorinated metal surfaces were observed using a scanning electron microscopy (SEM) and analyzed using an X-ray photoelectron spectroscopy (XPS). The Sn and Ag surfaces were covered mainly with SnF2 and AgF2 through the plasma irradiation respectively. The contact angle of the solder mounted on the metal substrates was measured to evaluate the wettability. The contact angle was minimized at the flow ratio of CF4/O2 which was 1/9. Surface fluorination by non-equilibrium plasma irradiation would be applicable to improve the wettability of flux-less solder"

Top recycler in Tuscon receives OHSAS 18001 certification

EMSNow: "Sims Recycling Solutions, the world's largest electronics recycler is pleased to announce that their facility in Tucson, AZ has become the seventh Sims Recycling Solutions facility in North America to achieve OHSAS 18001 certification."

P. KAY Metal Granted Broad Dross Elimination Coverage in New US Patent

ThomasNet: "P. KAY Metal has been granted United States Patent No. 7,861,915 providing broad coverage for its chemical dross elimination and reduction technology as used in the soldering process. The patent comes into force on January 4th 2011."

Ag Ni doping of SAC and lowsilver alloys

Factiva: "In this paper, the tensile tests were conducted at 25 degrees C to investigate the effect of Ag content and Ni doping on the microstructures and mechanical properties of Sn-3.0Ag-0.5Cu, Sn-2.0Ag-0.5Cu, Sn-1.0Ag-0.5Cu, Sn-1.0Ag-0.5Cu-0.05Ni and Sn-1.0Ag-0.5Cu-0.02Ni solders. The effect of strain rate on mechanical properties was investigated for each solder"

"In addition, the effect of temperature on mechanical properties was investigated for Sn-1.0Ag-0.5Cu-0.02Ni solder by conducting tests at -35 degrees C, 25 degrees C, 75 degrees C and 125 degrees C. Test results show that the elastic modulus, yield stress and ultimate tensile strength increase with increasing strain rate and Ag content, but they decrease with increasing temperature. The elastic modulus, yield stress and ultimate tensile strength are lower and the elongation is larger for Sn-1.0Ag-0.5Cu-0.05Ni solder compared with Sn-1.0Ag-0.5Cu-0.02Ni solder. The strain rate and Ag content dependent mechanical property models have been developed for Sn-Ag-Cu solders for the first time. In addition, the temperature and rate-dependent mechanical property models have also been developed for Sn-1.0Ag-0.5Cu-0.02Ni solder. The microstructures of solders were also analyzed. The Ag content affects Ag3Sn intermetallic compound dispersion and Sn dendrite size," wrote F.X. Che and colleagues.

The researchers concluded: "The microstructures of solder have fine Sn dendrites and more dispersed IMC particles for the high Ag content solder, which makes the solder exhibit high strength and yield stress."

Journal of Alloys and Compounds (The study of mechanical properties of Sn-Ag-Cu lead-free solders with different Ag contents and Ni doping under different strain rates and temperatures. Journal of Alloys and Compounds, 2010;507(1):215-224).

For more information, contact F.X. Che, ASTAR, Institute Microelect, 11 Science Pk Rd., Singapore 117685, Singapore.

BGA Reballing - Conversion from Pb Free (RoHS) to SnPb

BGA Reballing - Conversion from Pb Free (RoHS) to SnPb: "easiest solution is to reball those brand new BGAs to SnPb solder an implement them right into your normal assembly process.

eTech has the capability to reball 1 BGA or 20,000 BGAs. Give us a call and we will tailor a solution to fit your needs. Click here for additional details on our reballing process."

Outlook and Trends 2011: A Perspective

EMS007: "Smaller, Faster, Lighter, Less Expensive

The mantra of smaller, faster, lighter, cheaper will continue unabated. This trend has been unyielding now for nearly a generation. The demand created is well satisfied by breakthrough products like Apple’s iPad and iPhone. These devices have achieved unprecedented packaging density, with the iPhone 4’s PCBs having a silicon area/PCB area of 1.52 (Reference 1), meaning that the area of the silicon die is 52% greater than the area of the PCB. This tremendous density is accomplished by package-on-package (PoP) technology, in addition to 0201 and even 01005 passives and 0.3mm CSPs. Small passives like 01005 have been slower to arrive than first thought, most likely due to the difficulty in assembling them. Perhaps 2011 will be the year they become more widely established."

Most of the above improvements are evolutionary, but a revolutionary technology change is slated to emerge in 2011, 3D wafer stacking (http://www.tezzaron.com/about/about.html). This technology connects wafers directly, avoiding the additional PoP.

Lead-free Reliability will Become Accepted as Reasonable for Consumer Products

Two papers (Reference 2 and 3) at SMTAI in October last year demonstrated that lead-free reliability exceeds that of lead-containing solder in both drop shock testing and thermal cycling from 0 to 100°C. In addition, some lead-free assembled products were introduced in the late 1990s with no significant yield or field reliability problems. Adding these two facts together, it is time to accept that reasonable lead-free reliability for consumer products with something like a three to five year service life has been established.

The more harsh requirements of automobile and military environments, evaluated at thermal cycling regimes of -55°C to 125°C, for greater than five years do not look as promising for lead-free reliability. I expect that products in these types of environments will have lead-containing solder exemptions for years to come.

Convergence of Lead-Free Alloys will be Elusive

There are numerous “flavors” of lead-free alloys in use. SAC305 (3.0% Ag, 0.5% Cu, the balance Sn, followed by SAC105 and the tin-copper alloy (99.3% Sn, 0.7% CU with traces of Ni and Ge) ) is most commonly used in wave soldering. In the mid-2000s, it appeared that SAC305 would be the alloy of choice; however, SAC105 was shown to have superior drop shock performance, which is a great benefit to portable devices. In addition, work by Lee (Reference 4) has shown that additions of about 0.1% of Mn and other elements to SAC105 can increase its drop shock performance by as much as a factor of ten. The downside of SAC105 is that its melting temperature is about 6-8°C higher than SAC305. The tin-copper alloy is used in wave soldering because of its much lower cost. All of these things taken together suggest that it is highly unlikely that lead-free assembly will converge on one alloy.

Ronald C. Lasky, PhD, PE, Senior Technologist, Indium Corporation

EMS007 Webinar: RoHS CE Declaration of Conformity

EMS007: "On November 24, 2010, the EU Parliament voted to adopt a modified version of RoHS Recast. This recast of the Restriction of Hazardous Substances (RoHS) Directive includes requirements for creating a Declaration of Conformity to CE marking. This Webinar will cover the processes, requirements, and options for creating a CE Declaration of Conformity for a product under scope of RoHS Recast.

Topics covered in this webinar include:

Overview of RoHS Directive Recast;
Declaration of Conformity requirements of RoHS Recast;
RoHS declaration format;
Standards for RoHS compliance;
Procedures for Conformity assessment;
Explanation of new CE marking conformity requirements (Module A of Decision No 768/2008/EC);
Evaluation of the nature of risk;
Third-party involvement;
Internal production control;
Supervised product testing;
Random interval testing;
Role of software; and
Integration with other CE marking declarations."

EIPC Road Show Workshop on Reliability 2011

EIPC.org

EIPC are very pleased indeed to announce our Road show Workshop on Reliability planned for January and February 2011 in 4 European countries. The workshops are focused on Reliability.

Designers and quality engineers will hear of the latest practical findings about reliability testing and route cause defect analyses on PCBs with microvia-holes and solder connection with lead-free processes.

January 25th: Enthone Ltd., Woking, Surrey, United Kingdom

January 27th: University Prague, Prague, Czech Republic

January 31st: Huntsman, Basel, Switzerland

February 2nd: Isola Group, Düren, Germany

7th TMS Lead Free Solder and Interconnect Technology Workshop

TMS 2011:: "TMS 2011: Continuing Education:
7th TMS Lead Free Solder and Interconnect Technology Workshop
February 27 - March 3, 2011 • San Diego, California

This workshop is organized to serve as the industry roadmap for Pb free solder technology in high reliability and consumer electronic packaging and interconnections, with current industry needs and concerns serving as a driving force for research. Download the course flier (PDF)."

Solderless Assembly for Electronics (SAFE): The Book Project

PCB007 : "The book’s title, Solderless Assembly For Electronics (SAFE), is perhaps a bit provocative, but SAFE is believed to be an accurate summary word for products made without solder. The term SAFE was first used in a paper delivered at an IPC conference on lead-free solder a few years ago and was resurrected for this effort because only a relatively few people were in attendance at the conference. Other terms and titles were suggested or considered around the same SAFE acronym, “solder alloy free electronics” was one, but the prime consideration was given to the idea of making of solderless electronic assemblies and that the result of such products would, in fact, be safer and, ultimately, more reliable than traditional soldered assemblies."

When charted, the curve graphically illustrates how new or promising technologies often ride up a steep curve of heightened expectations and excitement early on to a high level of interest. Typically, this is followed by a precipitous descent into disillusionment when the promise is not immediately delivered. At this point, the only way out is up and disappointment can only be overcome by a long, slow learning climb to enlightenment. Once the industry has achieved enlightenment and understanding, progress and productivity kick in and the earlier promise is delivered.