Hot Alternative Energy News Stories | AltEnergyMag

Hot Alternative Energy News Stories | AltEnergyMag:

One of the issues that came out of the Roadmap was the rising cost of energy being of concern, not only to make more efficient products, but also the manufacturing costs involved.  Could we make something of this piece in that sense?

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Electronics Manufacturing by Inkjet Printing

Inkjet printing is of great interest in the field of electronics manufacture because its digital nature negates the need for physical tooling. A wide variety of active and passive materials are currently being investigated for use in inkjet printed electronics. These include semiconductors, light emitters and photovoltaic materials as well as dielectric materials and straight forward conductors. The range of conducting materials that can be printed is somewhat limited by the constraints of inkjet printing. Ideally, particle sizes should be below 1 micron and the viscosities and surface tensions of the fluids need to be tailored to the particular printhead being used. Regardless of these limitations, various technologies are now being implemented in the production of circuit boards, interconnects and antennas by inkjet printing. The properties of these inkjet
printed circuits do not currently mimic traditional PCB materials – in particular, the sheet resistances of inkjet printed materials tend to be significantly higher than traditional copper clad laminate and the minimum feature sizes are somewhat larger than state of the art semi-additive plating. However, inkjet printed circuit technologies are a still finding many applications which are particularly well suited to their properties and the digital nature of their application.



Steve Thomas
 Conductive Inkjet Technology Ltd.
 Cambridge, England


http://www.ipcoutlook.org/pdf/inkjet_printing_ipc.pdf

Overcoming the Next Set of Technology Hurdles

The latest computer chips offer more functionality but are also harder to manufacture with technology reaching fundamental limits. Where will it go from here? What are the implications? This article will show you.

http://www.ipcoutlook.org/pdf2/next_set_technology_hurdles.pdf

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Electrically conductive polymer compositions containing metal particles and a graphene and methods for production and use thereof

Espacenet: Polymer compositions containing a polymer matrix, a graphene that is covalently bonded to the polymer matrix and metal particles are described herein. A combined concentration of the metal particles and the graphene in the polymer matrix exceeds an electrical percolation threshold. In general, the graphene has a carbon:oxygen ratio of at least about 20:1 so as to impart a high electrical conductivity thereto. The polymer compositions can be used as a lead-free solder material, in which case they can allow multiple rework operations to take place at a connection. Methods for making and using such electrically conductive polymer compositions are also described.


Page bookmark     US8167190  (B1)  -  Electrically conductive polymer compositions containing metal particles and a graphene and methods for production and use thereof
Inventor(s):     BULLOCK STEVEN [US]; VANDERWIEL ROBERT W [US] +
Applicant(s):     LOCKHEED CORP [US] +
Classification:    
- international:     B23K1/018; B23K31/02; C08K9/02
- european:    
Application number:     US201113103016 20110506
Priority number(s):     US201113103016 20110506 

Expert committee seeks evidence on nanosilver

Call for information | Scientific Committees: The Scientific Committee on Emerging and newly Identified Health Risks (SCENIHR) has received a request for a scientific opinion on Nanosilver: safety, health and environmental effects and role in antimicrobial resistance(17 KB).

Scope of the call for information:
Interested parties are invited to submit any relevant information that could assist the scientific committee with the assessment of the safety, health and environmental effects of nanosilver. In particular, the Scientific Committee is interested in receiving any scientific information related to the "nano" forms of silver.

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One of the European Commission's scientific committees is seeking information on the health and environmental effects of nanosilver particles used in medical and consumer products. The consultation will run until 4 June.

Information received by the committee on emerging and newly identified health risks (SCENIHR) will feed into a commission review due to be completed by early 2013.

Nanosilver is one of the most common nanomaterials in consumer goods because of its antimicrobial properties. But there are concerns about its effects on bacteria in sewage works and rivers, as well as its potential to increase antibiotic resistance.

MEPs wanted nanosilver banned from electrical and electronic products under the RoHS directive, while some NGOs have called for restrictions on its use in consumer goods until there has been a more thorough risk assessment.

The commission issued a separate request to SCENIHR for advice on the health effects of nanomaterials used in medical devices at the end of March.

Electrically Conductive Adhesive from Henkel Compatible with Multiple Metals

EMSNow: Leveraging research regarding contact resistance performance, Henkel Electronic Materials has developed an electrically conductive adhesive (ECA) that overcomes the drawbacks of older generation ECAs and extends the material’s advantages to multiple applications. The adhesive system, HYSOL ECCOBOND CE 3103WLV, provides exceptional contact resistance stability on surfaces such as OSP copper and Sn alloys– metals which have previously been challenging for ECAs

ECAs have been used for high-reliability applications such as automotive, medical and telecom products for some time, as they offer lower temperature processing, fine-pitch capability and improved thermal cycling resistance.  With these applications, ECAs have most often been employed on devices with noble metallizations such as gold, silver, palladium and even ceramic substrates but have had limited success on common electronic metals such as copper and Sn alloys.  Technical research conducted by Henkel, however, has revealed that electrochemical corrosion of these metals under elevated temperature and humidity is the root cause of the unstable contact resistance and, using this understanding as a foundation, Henkel developed HYSOL ECCOBOND CE 3103WLV to overcome these issues and deliver multi-metal compatibility.

The material has been incorporated into a variety of applications and, most recently, optical technology powerhouse, LensVector, has selected HYSOL ECCOBOND CE 3103WLV for use with its AutoFocus (LVAF) product.   The LVAF is the world’s smallest autofocus device, which uses a unique patented technology to transform a single liquid crystal cell into a variable focus lens which can then be integrated by camera module manufacturers to deliver autofocus capability.

LensVector’s Vice-President of Engineering, Bahram Afshari, explains the demanding requirements of its product and why the company partnered with Henkel.  "Not only do the contacts between the LVAF and the main module serve to make the electrical connections, but must also meet the challenging reliability requirements for camera phones, notebook computers and other handheld consumer electronic devices that incorporate these modules," says Afshari.  "HYSOL ECCOBOND CE 3103WLV delivers the electrical conductivity and reliability performance in an easily dispensed, high-yield, low- temperature cure ECA.  In fact, the cure temperature is well below most traditional ECAs, which gives us added process and module material selection flexibility."

Chemo-rheological characteristics of a self-assembling anisotropic conductive adhesive system containing a low-melting point solder

ScienceDirect.comTo achieve the excellent wettability of a solder in an anisotropic conductive adhesive (ACA) in micro-packaging technology, not only the removal of the oxidized layer of the solder but also the chemo-rheological phenomena of the thermally induced self assembly of low-melting temperature solder powders were investigated for ACA applications. Both the optimum kind and amount of reductant were determined in this study to remove the oxidized layer formed on the solder surface in ambient environment. The solder wetting test was performed to observe the chemical and rheological compatibility between the solder, polymer matrix, and reductant. The thermal analysis was done using differential scanning calorimetry (DSC) analysis and rheometer test. Several chemical reactions by the reductant were proposed, and the mechanisms were postulated. It is believed that the reductant reacts with the oxidized layer, amine, and epoxide group, respectively. The relation between conversion and glass transition temperature of the polymer matrix was also obtained from DSC.


Microelectronic Engineering
Volume 87, Issue 10, October 2010, Pages 1968–1972
Chemo-rheological characteristics of a self-assembling anisotropic conductive adhesive system containing a low-melting point solder ☆
Ji-Won Baeka, b, Keon-Soo Janga, b, Yong-Sung Eoma, , , Jong-Tae Moona, Jong-Min Kimc, Jae-Do Namb, , 
a Next Generation Packaging Team, Electronics and Telecommunications Research Institute, 161 Gajeong-dong, Yuseong-gu, Daejeon 305-700, Republic of Korea
b Department of Polymer Science and Engineering, Sungkyunkwan University, Suwon, Republic of Korea
c Department of Mechanical Engineering, ChungAng University, Seoul, Republic of Korea
Received 23 July 2009. Revised 2 November 2009. Accepted 7 December 2009. Available online 29 December 2009

Effects of novel carboxylic acid-based reductants on the wetting characteristics of anisotropic conductive adhesive with low melting point alloy filler

ScienceDirect.com: A low viscosity epoxy resin with carboxylic acid-based novel reductants was introduced to improve the process ability and reliability of an anisotropic conductive adhesive (ACA) resin with a low melting point alloy (LMPA) filler system. The curing degree of the ACA resin and the melting of the LMPA filler were investigated using differential scanning calorimetry (DSC) conducted in the dynamic mode in order to control the curing conditions such as the reaction temperature and a melting temperature of solder. The temperature-dependent viscosity characteristics of the ACA resin were investigated using a rheometer. The compatibility between the viscosity of a polymer matrix and a melting temperature of solder was characterized to optimize the processing cycle. Three different types of carboxyl acid-based reductants were added to remove the oxide layer on the surfaces of the filler particles and the conductive pad. Good wetting properties were achieved between the LMPA filler and the Cu pad in the epoxy resin using these carboxylic acid-based reductants.


Microelectronics Reliability
Volume 50, Issue 2, February 2010, Pages 258–265
Effects of novel carboxylic acid-based reductants on the wetting characteristics of anisotropic conductive adhesive with low melting point alloy filler
Hyomi Kima, Jongmin Kimb, Jooheon Kima, , 
a School of Chemical Engineering and Materials Science, Chung-Ang University, Seoul 156-756, Republic of Korea
b School of Mechanical Engineering, Chung-Ang University, Seoul 156-756, Republic of Korea
Received 14 August 2009. Revised 28 October 2009. Available online 16 December 2009.

Creative Materials offers new lower cost silver inks and adhesives

Global SMT and Packaging: Creative Materials, Inc., has continued to develop promising lower cost alternatives to conventionally manufactured silver inks and adhesives. With several new products qualified for production, we are confidently expanding our lower cost product line. In applications where a slight reduction in conductivity may be acceptable, these new “economical” products can provide cost savings while delivering the same high-quality performance of our standard silver inks and adhesives.


Two new successful lower cost products:125-43A/B119-44, Solvent-Resistant Electrically Conductive Ink—Developed for touch screens and shielding applications, this product has been successfully implemented in the manufacture of RFI-shielded displays. Adapted from CMI’s highly regarded 118-09A/B, 125-43A/B offers the same properties and chemical composition, with a slight decrease in overall conductivity. http://server.creativematerials.com/datasheets/DS_125_43A_B.pdf
125-46A/B,C, Economical Electrically Conductive Epoxy Adhesive—With little compromise to overall conductivity, this product was developed for making attachments on electrical and mechanical devices.  Available for a wide range of dispensing options, 125-46A/B,C can be used with direct write and jet-dispensing systems.  Based on the chemistry of our popular 124-08A/B,C, this product is also available in a two-component easily mixed one-to-one system and a one-component pre-mixed system. http://server.creativematerials.com/datasheets/DS_125_46.pdf

Micro-friction stir welding project

LinkedIn: Vitor Marques • I am now engaged in a European project that aims to explore micro-friction stir welding to be used in SMT, therefore avoiding the use of solders/flux and formation of intermetallics.

This technology looks promising and would be of special interest for selective soldering, power electronics, high temperature electronics, heat sinks and packaging for deep sea applications. So far this technology is able to perform spot welds in 200-100microns Cu sheet with heat being confined to the weld itself. Our aim is to reach a spot weld of 200microns diameter. If anyone require more information please let me know. Soon a project website will be launch.

If anyone require more information about it, please let me know.

Printed Electronics Start to Show Up in Volume Hybrid Products

SEMI.ORG: But 2012 will see introduction of an assortment of potentially significant new applications of wide-area, solution-processed materials in commercial lighting and displays, including potentially lower cost OLED light panels, better ITO alternatives, force-sensitive touch screens, and possibly even some flexible display backplanes.

Characteristics of solderable electrically conductive adhesives (ECAs) for electronic packaging

Scopus: This study investigated the effect of the viscosity of the ECAs using a low-melting-point alloy (LMPA) filler on its bonding characteristics. The curing behaviors of the ECAs were determined using Differential Scanning Calorimetry (DSC), and ECA temperature-dependant viscosity characteristics were observed using a torsional parallel rheometer. The wetting test was conducted to investigate the reduction capability of ECAs and the flow-coalescence-wetting behavior of the LMPAs in ECAs. Electrical and mechanical properties were determined and compared to those with commercial ECAs and eutectic tin/lead (Sn/Pb) solder.

In the metallurgically interconnected Quad Flat Package (QFP) joint, a typical scallop-type Cu-Sn intermetallic compound (IMC) layer formed at the upper SnBi/Cu interface after curing process. On the other hand, a (Cu, Ni)6Sn5 IMC layer formed on the SnBi/ENIG interface. In addition, the fracture surface exhibited by cleavage fracture mode and the fracture was propagated along the Cu-Sn IMC/SnBi interface. The extremely low-level viscosity of ECAs had a significant influence on the flow-coalescence-wetting behavior of the LMPAs in ECAs and also on the interconnection properties. Stable interconnected assemblies showed good electrical and mechanical properties

Molex Introduces New CMC Standard Header and Solder-Mount Headers with Press-Fit Terminals

Factiva: The new 154-circuit, three-pocket, right-angle header with compliant-pin terminals improves productivity and reduces assembly costs by enabling a solder-free process, as opposed to conventional press-fit type mounting processes. The 154-circuit header features 120 x 0.635mm (.025’) signal pins, 24 x 1.50mm (.059’) terminals and 10 x 2.80mm (.110’) power pins, supporting high currents in applications such as large ECUs. The sophisticated and robust design of the integral guiding plate protects the 5 terminal rows and ensures positioning, while being able to withstand high-vibration levels up to 10G. Ideal for heavy-duty agricultural equipment applications, the 154-circuit connection system performs up to 50 mating cycles for mating and unmating of multiple ECUs on different applications

Optimization of the Soldering Process With ECAs in Electronic Equipment: Characterization Measurement and Experimental Design

IEEE Xplore : With the introduction of the European Directives restrictions of hazardous substances, electrically conductive adhesives (ECAs) have received great attention in the field of electronics as a possible replacement of the traditional tin-lead soldering technology. So, in this new context, the analysis and the characterization of these alternative materials represent a fundamental topic, above all, from the industrial point of view. Nevertheless, studies on ECAs have rarely been reported in the literature, but more recently research has started to focus on this specific topic.

After a comparative assessment concerning soldering materials, this paper focuses attention on their characterization through measurement in order to verify the electrical behavior of the isotropic silver conductive adhesive.

In addition, since the soldering process is affected by a large number of variables such as the thickness of the conductive adhesive film, radial velocity, and curing temperature, the optimal selection of the factors is carried out through experimental design theory and the dual-response approach by means of generalized linear models.

In this paper, the experimental and comparative studies on soldering made up of epoxy adhesives are carried out, in particular, the adhesives constituted by metallic particles (silver), normally in the form of flakes, in a polymer matrix are considered. The novelty of the kind of adhesive considered is the Ag filler loadings of 50-65% by volume. At these loadings, the materials achieve the percolation threshold and are electrically conductive in all directions after the materials are cured. Two different types of conductive adhesives, characterized by different chemical structures and compositions, are experimented and tested.

Then, since the lead-free soldering process is characterized by several critical factors, a statistical approach is used to optimize this process. Experimental results obtained by testing samples with ECA materials prove the validity of this paper.

The value of this paper is in the application of a statistical approach to these adhesive materials in order to achieve the optimization of the soldering process with a small number of treatment combinations, satisfying at the same time the stringent requirements and achieving robust electrical interconnections.

Can Conductive Epoxies Replace Solder?

Circuitmart?: It's a question that's been asked many times over the ages, especially since the original advent of RoHS appearing on the horizon. It's something we've touched on before in one of our other diatribes on conductive epoxy. Fundamentally yeah, you could consider it, but from a practical standpoint, not really.

This was originally examined back in the early days of getting ready for RoHS. Motorola Schaumberg IL, did some major investigation into this at the time and they decided absolutely no. There's a number of limitations with conductive epoxies regarding how they fare in terms of robustness compared to tin lead solder. Jim, do you want to elaborate on that a little bit?

Jim

Probably the most predominant concern is that the conductivity of the material degrades over time. That is, the net contact resistance goes up. So, for many applications that can eventually damage your signal flow through your circuit. That's the biggest one.

Other issues that are raised are difficulties reworking, and some of the structural properties. Depending upon what your failure modes are, in some cases the epoxies can be more robust. But in others, cycling or vibration and so forth, they are less robust.

The final issue is cost. Ca-ching, ca-ching. Yeah, most of the ones that work successfully are filled with silver or gold. Silver is just plain expensive. Phil, did that Motorola study have a rough estimate, even back in those days when silver was cheap?

Phil

Yeah, the study was done at least 12 or 15 years ago and the cost of silver-filled conductive epoxy was at that point about 10 times the cost per gram of tin lead solder. Can you imagine what gold-filled epoxies were going for?

Jim

One of the possibilities that has been tested many times is a copper-filled epoxies, but nobody has mastered those to achieve the reliability level of silver-filled.

Phil

So, one the surface, the idea looks really good. It's a no clean, it's lead-free, you don't have to worry about VOCs, no cadmium, chromium or mercury.

But when you start cross sectioning, at least in its present state it's not a great idea. But remember, things tend to change and improve, so, you never know. And with that, we say thank you for tuning in to Board Talk and this is Jim Hall and Phil Zarrow, The Assembly Brothers, saying whatever you do –

Jim

Don't solder like my brother

Phil

And don't solder like my brother. And quit snorting the conductive epoxies, too. It's not good for you.

Views: 758

Comments

Interesting talk on conductive epoxies. We have looked at this for many years, we used high volume Ag filled epoxies from the 1970's. This has reduced over the years due to changes in chip packaging/hybrid assembly. We saw no significant problems with using Ag epoxies even in extended life trials. Problem is price. Price problem is embarrassment. Majority of conductive epoxies are used in mil/hi-rel applications.

The few main suppliers have milked this business since 1960's. I can only use the last data I have (from 2001) but at that time the main US supplier was selling their Ag epoxy for about $1.75 per gram, main Asian source US$1.35 per gram. Both said these were competitive prices! At that time I was buying high purity electronic grade epoxies for about $0.003 per gram and Ag flake or powder for $0.15 per gram.

I spoke often to the main manufacturers to try to get them to reduce pricing to an acceptable level. I compared total cost of ownership of 96S solder or Ag epoxy as solder replacement for lead attach. The process savings using epoxy was enormous. No fluxing, reflow,cleaning just relatively low temperature curing.

Bottom line was we were willing to pay over $0.50 per gram. Volume would have been huge. No main supplier was interested. 4 times we had small epoxy manufacturers OEM the material to our specifications.

Each supplier either went out of business, was taken over or had "changes in strategic direction" after a few months manufacturing. Basically we gave up and looked at other ways to increase soldering efficiencies. I don't think we will ever have reasonable pricing in this sector due to the high historical margins for the suppliers.

Allan Dowie, BI Technologies Ltd

New Electronic Materials to be Debuted at Productronica 2011 in Munich

TMCnet.com: With the industrial electronics market in mind, Henkel has developed a pair of breakthrough electrically conductive adhesive (ECA) technologies that overcome many of the shortcomings of competitive materials.

ABLESTIK ICP-3535M1 is a single component ECA that enables manufacturers to incorporate lower cost tin-terminated components and thus obtain a cost-effective, lead-free, high reliability assembly. The material has excellent electrical and adhesion stability, no bleeding or wicking on miniaturized components and can be cured quickly at low temperature. For automotive applications where both high flexibility and excellent conductivity are required, Henkel has designed the first-ever high-end conductive silicone adhesive technology. In fact, ABLESTIK ICP-4000 has already been qualified and is being used for automotive sensor products where components are bonded to metal leadframes inside plastic housings.

Historically, the CTE (coefficient of thermal expansion) mismatch between the metal and the plastic has introduced damaging stress to the device. But, Henkel's conductive silicone technology is able to absorb this stress, maintain the bond and deliver the electrical interconnect between the component and the leadframe.

Fracture behavior of Cu-cored solder joints

Scopus: Copper-cored solder can be regarded as the next-generation solder for microelectronic semiconductors exposed to harsh operating conditions owing to its excellent sustainability under extreme thermal conditions, e.g., in microelectronic semiconductors used in transportation systems.

Cu-cored solder joints with two different coating layers, Sn-3.0Ag and Sn-1.0In, were compared with the baseline Sn-3.0Ag-0.5Cu solder. The fracture strength and failure mode were examined using the high-speed ball-pull and normal-speed shear tests. The Cu-cored solder joint with the Sn-1.0In plating layer exhibited the highest ballpull and shear strengths. In addition, it showed a much lower percentage of interface fracture between the Cu-core and plating layer than the interface fracture percentage in the Sn-3.0Ag plating layer due to the improved wettability between the Cu-core and Sn-1.0In plating layer

Kim, Y.a , Choi, H.a , Lee, H.a , Shin, D.a , Moon, J.b , Choe, H.a

a School of Advanced Materials Engineering, Kookmin University, Jeongneung-dong, Seongbuk-gu, Seoul 136-702, South Korea

b MK Electron Co., Ltd, 316-2 Geumeoh-ri, Pogok-eup, Cheoin-gu, Yongin-si, Kyeonggi-do 449-812, South Korea

Sn-coated nanotubes for nanochips

Factiva "A Sn coated single multi-walled carbon nanotube (MWCNT) was connected between Cu terminals and with other MWCNTs using tin solder. HRTEM micrographs showed the interconnections between two sides as well as on one side of a Cu grid," researchers in Tainan, Taiwan report.  "MWCNTs not only formed straight connections but also bent in the middle with little damage to the graphenes of nanotubes. The process also joined a single nanotube with other nanotubes at their tips as well as in the middle, and in various modes including series and parallel. The connections were found to be stable in air and under TEM observations, and could be made by both small and large diameter MWCNTs," wrote J. Mittal and colleagues, National Cheng Kung University.  The researchers concluded: "The process uses existing Sn-based soldering technology and provides a way for the development of CNT-based nanochips

Occam Portfolio Assigned Patent

Factiva: "Joseph Charles Fjelstad, Maple Valley, Wash., for 'electronic assemblies without solder and methods for their manufacture.'

The abstract of the patent published by the U.S. Patent and Trademark Office states: 'The present invention provides an electronic assembly 400 and a method for its manufacture 800, 900, 1000 1200, 1400, 1500, 1600, 1700. The assembly 400 uses no solder."

Solder-free Connectors Designed for LED Arrays

EDNAsia.com: "Molex Inc.’s solderless LED Array Holders for Cree’s energy-efficient XLamp MP-L and CXA2011 arrays feature compression contacts that power the arrays while eliminating the need for hand soldering or expensive SMT equipment. The holders also provide a stable connection in high-ambient temperature.

Ideal for light fixture OEMs, the LED Array Holders simplify the design and assembly process by using only two screws to secure the connector to the LED and thermal interface. Utilizing the Molded Interconnect Device (MID) technology, the holders allow the MP-L LEDs to be powered in either series or parallel, providing two options for Cree OEMs: high-voltage series wiring for lamp applications and low-voltage parallel wiring for fixtures."