SMA Evolution
Surface mount adhesives have been part of the assembly landscape for so long that they have almost become an afterthought. Until recently, these “glues」 as they are so often referred to, were just expected to perform as required and, for the most part, they did. Older generation materials required a fairly high peak cure temperature of between 140° to 150°C. But some components – particularly some lower cost components – heavily relied upon in the high-volume consumer electronics market could not withstand the heat input required for adhesive cure and, thus, reliability was compromised. This led to the engineering of SMAs with lower cure temperatures that utilized a very unique approach so as to enable sufficient cured strength for maximum performance during soldering. Based on these requirements, a new formulation was developed that maintained historical chipbonder properties, yet allowed for a significantly lower cure temperature – as low as 85°C. The combination of lower cure temperature, material strength and reduced rate of temperature rise of these newer generation materials dramatically reduced thermal shock and improved reliability, enabling in-line, automated assembly of temperature-sensitive components.

Enter Lead-Free
Lower temperature cure adhesives became the industry standard, essentially resolving the dilemma of automated processing of temperature-sensitive components and allowing reliable, in-line surface-mount assembly for a wide range of devices. And, while the benefits of these materials were many, the advent of lead-free manufacturing pushed them to their performance limits and it became clear that yet another adhesive innovation would be required to meet the demands of lead-free process conditions. With years of Pb-free research behind them, the materials scientists at Henkel worked diligently to develop an adhesive that maintained the low temperature cure, yet could withstand the elevated process temperatures of lead-free. Henkel’s next –generation SMA, Loctite? 3629 delivers all of the capabilities of former generation low-temperature cure adhesives, yet is capable of retaining its strength during high-temperature soldering processes. Loctite 3629’s advanced formulation maintains the benefits of lower energy input for cure, but also possesses lower yield points to enable faster dispensing and printing ability and higher adhesive strength to handle the extreme temperatures of lead free and the pull imposed on components resulting from the greater surface-tension of lead-free alloys.

RoHS Compliant and Pb-free Capable: The Best of Both Worlds Symposium E: Pb-Free and RoHS-Compliant Materials and Processes for Microelectronics
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April 11 - 12, 2007
Chairs Carol A. Handwerker Purdue University
Katsuaki Suganuma Osaka University
Heidi L. Reynolds Sun Microsystems, Inc.
Jasbir Bath Solectron Corporation

Invited paper

SESSION E1: Global RoHS and Environmental Regulations
Chairs: Jasbir Bath and Carol Handwerker
Wednesday Morning, April 11, 2007
Room 3005 (Moscone West)

8:30 AM *E1.1
Environmental Regulations and Materials Technology in the Electronics Industry Robert C. Pfahl, International Electronics Manufacturing Inititiative-iNEMI, Herndon, Virginia.

9:00 AM *E1.2
Management Methods for Controlling Pollution by Electronic Information Products - China RoHS. David Towne, Sun Microsystems, Inc., Menlo Park, California.

9:30 AM *E1.3

SESSION E2: Tin Whisker Nucleation and Growth
Chair: Heidi Reynolds
Wednesday Afternoon, April 11, 2007
Room 3005 (Moscone West)

1:30 PM E2.1
Sn whisker: Understanding and Prevention? John Osenbach, Agere systems, Allentwon, Pennsylvania.

2:00 PM E2.2
An Electrical Characterization of Tin Whiskers Robert D. Hilty and Ned Corman; Technology, Tyco Electronics, Harrisburg, Pennsylvania.

2:30 PM BREAK

3:00 PM *E2.3
Sn Whisker Formation: Stress Generation at the Sn-Cu Interface. Gery Ryan Stafford, Carlos Beauchamp, Ugo Bertocci, Espen Sandnes and William Boettinger; Metallurgy Division, NIST, Gaithersburg, Maryland.

3:30 PM *E2.4
Interaction of Stress, Intermetallic Formation and Defect Kinetics in Sn Whisker Formation. Eric Chason, Lucine Reinbold, Nitin Jadhav, Vernorris Kelly, Jae Wook Shin, Eric Buchovecky, Ramanarayan Hariharaputran and Sharvan Kumar; Division of Engineering, Brown University, Providence, Rhode Island.

4:00 PM E2.5
Distribution and evolution of stress in Sn layers on Cu Nitin Jadhav, Lucine Reinbold, Vernorris Kelly, Jae Wook Shin, Anthony Johnson, Michael Task, Sharvan Kumar and Eric Chason; Brown University, Providence, Rhode Island.

4:15 PM E2.6
Characterization and Modeling of Intermetallic Growth Kinetics in Sn Layers on Cu. Eric Buchovecky, Lucine Reinbold, Ramanarayan Hariharaputran, Eric Chason and Sharvan Kumar; Division of Engineering, Brown University, Providence, Rhode Island.

4:30 PM Next Steps: "Open Discussion" of Fundamentals of Tin Whisker Formation and Needed Critical Experiments.RoHS Compliance Letter
Corporate Commitment
Due to increased worldwide environmental concerns, the need for lead free solutions in electronic components and systems is receiving increasing attention within the semiconductor and electronics industries. Lattice is fully supportive of the various industry efforts throughout the world to phase out the use of lead and other undesirable elements from electronic equipment materials and manufacturing processes.

Lattice remains committed to continually reducing its impact on the world's natural environment and works closely with our customers and suppliers to identify and rapidly eliminate hazardous substances from its products.

Resource Conservation
Environmental protection is more than just meeting standards. All corporate activities must be implemented with the environment in mind. Lattice's goal is to develop all new products such that they reduce space, materials and power consumption for an equivalent electrical function. In turn, this allows our customers to continually reduce their impact on the environment.

ISO14001
ISO14001 is an international standard for environmental management systems. Companies that are ISO14001 registered have demonstrated an internal program for the management of hazardous waste and implementation of recycling programs. This international recognition certifies a company's commitment to preserving the natural environment. All Lattice subcontract manufacturers are ISO14001 registered, and are routinely reviewed to ensure continued compliance.

Lead Free and RoHS Compliant Packaging Initiative

Pb Free Central

RoHS Compliance

Design & Layout

Assembly

Nitrogen Reflow
Fabrication

Purchasing

Pb Free Tips

You Are Here: Pb Free Assembly

Pb-Free Assembly

An ideal lead-free transition team has trained personnel in purchasing, inventory management, fabrication and process control. Purchasing and procurement specialists are versatile enough to fully understand and track a variety of changing conventions association with Pb-free assembly. Inventory personnel understand differences between eutectic and lead-free components. Particularly, they are attentive to the adverse consequences of mistaking one for the other. They also maintain stringent control over incoming vendor components from a variety of supplier bases; and once in house, segregate those components and maintain proper inventory of them.

There are differences between eutectic and lead-free assemblies, not only in terms of different thermal profiles, inspection and rework criteria, but also because lead-free assemblies tend to have latent defects that are absent in eutectic assemblies. One of those defects is “whisker formation.」 This phenomenon is created when tin whiskers or electrically conductive, hair-like structures grow outward from tin, zinc, gold, cadmium, indium or silver.


Solder joint embrittlement is created over time as a result of a latent defect. This is due to the absence of lead in the joint, which makes the remaining alloy hard. Over time, this hardening alloy can show signs of cracking and micro-cracking. Signs of fatigue are more prevalent in PCBs subjected to motion- or vibration-based applications. This latent defect places greater pressures on process controls and require tighter assembly re-work and inspection tolerances.

Statistical Process Control is used in manufacturing process to anticipate and prevent any variation of critical characteristics and reach best quality targets.

Continuous improvement approach based on root cause identification and lessons learned from our day to day activities is deployed systematically inside our company.

Development of quality supplier performance with permanent cooperation is the key to get best manufacturing process control using preventive quality methods and tools.

Training all the employees on a regular basis is part of our policy for implementing a zero defect culture in the company.
Environmental Policy and commitment to sustainable development
HUMIREL products and services are aimed at improving the quality of life for everyone, anywhere in the world. We commit to actively work for the protection of the environment throughout our day to day activities. Using integrated quality and environmental ISO14001- compliant Management System, HUMIREL is committed to:

? Design and manufacture products and technologies that contribute or enable a sustainable development of the planet.
? Achieve and maintain compliance with environmental laws and regulations.
? Infuse a fighting spirit among its employees towards reducing the impact of their work on the environment.
? Prevent pollution and optimize the use of natural resources.
? Implement an assessment system to ensure continuous improvement in our daily activities.

RoHS
What is RoHS ?
The European Union published the Restriction of the Use of Certain Hazardous Substances in Electrical and Electronic Equipment Directive ( RoHS Directive, 2002/95/EC) on February 13, 2003. This Directive takes effect on July 1, 2006, and with some exceptions (Annex) totally bans the use of (Article 4.1):

lead,
mercury,
cadmium,
hexavalent chromium,
polybrominated biphenyls (PBB's),
polybrominated diphenyl ethers (PBDE's),

in electronic and electrical products and equipments.

This directive will become applicable to producers who are selling Electrical and Electronic Equipment (EEE) in European Countries and that fall under the following categories:
Household appliance
IT and communication equipments
Consumer equipments
Lighting equipments
Electrical and electronic tools (with the exception of large scale stationary industrial tools
Toys, leisure and sport equipments
Automatic dispensers
Medical devices (with exemption of implanted and infected products) and monitoring and control instrumentation are not under the directive scope.

KEY ELEMENTS
Definition of max contents
Council Decision COM(2004) 606 (adopted Sept. 23, 2004), amends the Annex of the RoHS Directive to permit-- in any application that was not already exempted--a homogenous material to contain a maximum of:

0.1% (1000PPM) lead by weight.
0.1% mercury by weight.
0.01% cadmium by weight.
0.1% hexavalent chromium by weight.
0.1% polybrominated biphenyls (PBB's) by weight.
0.1% polybrominated diphenyl ethers (PBDE's) by weight.
What does "homogenous material" mean?
Homogenous material is defined as material that cannot be “mechanically disjointed」 into different materials. 」Mechanically disjointed」 means that the materials cannot in principal be separated into other materials by mechanical methods such as unscrewing, cutting, crushing, grinding or abrasive processes. A clean separation is not a requirement and this definition is intended only to indicate that materials such as plastics, metals, and coatings, etc., should not contain the restricted substances.. RoHS Compliance Plan
To Our Customers:

Aries Electronics, Inc. is committed to RoHS compliance and will make every effort to assist our customers by making available as much information as possible. This information will continue to change as additional data becomes available.

The Restriction on Hazardous Substances (RoHS) and Waste Electrical and Electronic Equipment (WEEE) directives are aimed at reducing the hazardous materials content in electronic products as well as increasing the recycling efforts for these products and take effect July 1, 2006. RoHS specifically bans or restricts the use of lead, cadmium, mercury, hexavalent chromium, polybrominated biphenyls (PBB) and polybrominated biphenyl ethers (PBDE).

Cadmium, Mercury, Hexavalent Chromium, Polybrominated Biphenyls & Polybrominated Diphenyl Ethers

To the best of our knowledge and belief Aries Electronics, Inc products do not contain cadmium, mercury, hexavalent chromium, polybrominated biphenyls (PBBs), and polybrominated diphenyl ethers (PBDEs) as either intentionally added ingredients or as unintended impurities in concentrations exceeding EU regulatory limits. This statement is based upon information provided by our raw material suppliers. Please be advised that Aries Electronics, Inc. does not analyze its products for substances not purposely added. Trace amounts of any chemical and substance might be found as impurities in any product, therefore Aries Electronics, Inc. assumes no liability in connection with this information. Aries Electronics, Inc. does not use these substances in production processes.

Lead

Nearly all contact and pin materials are RoHS compliant, although some may contain small quantities of lead within the 4.0% by weight exemption allowed by the RoHS directive. The gold and matte tin plating used on Aries Electronics, Inc contacts and pins are RoHS compliant. Products that are gold and matte tin plated can withstand the elevated temperatures and long dwell times required for lead-free reflow.

Changeover Status

Aries Electronics, Inc. has a broad product offering, however we are targeting a complete changeover of parts that are planned for RoHS compliance by as early as September 1, 2005 and plan to be operationally compliant on or before the July, 2006 deadline. Due to the uncertain timetable for the availability of RoHS compliant components, we are unable to specify firm release dates for the RoHS compliant products. Once RoHS compliant parts are available, the “Product Data Sheet」 section on our website will be updated with the corresponding information. The bottom right hand corner of the data sheet will contain a Lead Free/RoHS Compliant symbol indicating that the products on that specific data sheet are now available as RoHS Compliant.withstand the elevated temperatures used in lead-free reflow soldering processes. We are in the process of converting to a UL 94V-0 4/6 nylon material which will withstand the 260°C peak reflow temperature. Regarding the pins and contacts, we are in the process of converting our existing tin lead plating to matte tin. A compliant gold plating option is also available on some of our products (Ref: Product Data Sheet for details).

Correct-A-Chip?

Correct-A-Chip? (CAC) products are not RoHS compliant at this time, and are not intended to be converted as standard practice. If you are interested in an RoHS compliant version, our sales department will be happy to work with you in determining feasibility, special part numbers, pricing, and ordering requirements.

Cable Assemblies

Cable assemblies are in the process of being converted to RoHS compliance. We are working with our cable suppliers in obtaining components (wire, insulation, jacket compounds, etc.) that meet the requirements of the RoHS/WEEE directives. As with other products, once the specific cable family is converted, the corresponding product data sheet will be revised. Refer to the specific cable “product data sheet」 for additional details.

Customer Service and Support RoHS Lead-Free Test and Inspection
Legislation is driving the need for lead-free and environmentally friendly material sets in the printed circuit board industry. The RoHS (Restriction of Hazardous Substances) directive commonly know as the 'lead-free' directive. This directive restricts the usage of Lead, Mercury, Cadmium Hexavalent chromium (Chromium VI or Cr6+), Polybrominated biphenyls (PBB) , Polybrominated diphenyl ether (PBDE).

This new material set means questions about the reliability of products, process issues, and many other considerations that have been long established for tin-lead solders. In general lead-free is a less forgiving process, which means that defect levels are likely to increase and the need for inspection for process control and defect containment will increase.

The creation of www.lead-freetest.com was to help customers with gathering lead-free /RoHS data, paper/articles, events, resources, etc. This website is a compilation of what is happening in lead-free in the industry and is a great resource for customers of all types. This valuable resource is available as a free service to our valued customers and to others with an interest in lead-free.

Lead-Free News

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A Study of Lead-Free Wave Soldering
(AIM) As lead-free in wave soldering increases, questions about copper dissolution into lead-free alloys have arisen. This study explores this question and provides data and discussion to support the industry issue.

Fragility of Pb-free Solder Joints
(SMTnet) Recent investigations have revealed that Pb-free solder joints may be fragile, prone to premature interfacial failure particularly under shock loading, as initially formed or tend to become so under moderate thermal aging. This study explores this in depth.

RoHS Compliance and Pb-free Capability: One in the Same?
(SMT) Though many in the industry would lead you to believe that a RoHS compliant product ensure lead-free process capability, in fact, nothing could be further from the truth. This paper explores this question in detail.

Agilent statement on the Restriction of Hazardous Substances (RoHS) Directive
(Agilent Technologies) Agilent Technologies provides a drawer statement to customers on the RoHS situation.

China RoHS: Ready or not, it’s here
(Semiconductor International) Editorial style comments on the China RoHS transition.Right Recipe Can Cut Pb-Free PCB Costs
Written by Administrator
Tuesday, 01 July 2008
ROMULUS, MI – The right combination of materials, finishes and solders can have a marked effect on bare board cost and reliability.

Indeed, according to Jim Kelch, director of sales/marketing, at PWB fabricator Saturn Electronics Corp., the right recipe can cut board costs as much as 30%.

In a Webinar Monday, Kelch, along with representatives from Isola Group and Florida CirTech, laid out how.

The move to Pb-free creates a host of indirect cost drivers, said Kelch, including increased scrap rate (due to delamination and decreased solderability) and the need for additional storage and handling steps (generally, pre-baking).

The response, according to Kelch, is designers are calling out FR-4 laminates with 180° Tg and 340° Td (time to decomposition at temperature). But while FR-4 is RoHS compliant, it is not always right for Pb-free assembly, he explained, while 180° Tg does not guarantee adequate Td.

Saturn’s proposed solution: mid-grade Pb-free capable laminates that meet IPC-4101/99 (filled) or IPC-4101/124 (unfilled), with a minimum 150° Tg and 325° Td.

The benefits, he says, are a 15 to 20% cost savings on raw materials; lower moisture absorption (0.10 to 0.25%); higher interlaminate adhesion (peel strength = T-288 >10 min.), and high copper-to-laminate peel strength.

Dave Coppens, technical account manager at laminate supplier Isola, discussed test results for the company’s IS400 product, which reportedly performed well under tests for TGA, DSC, Td, weight loss % by TGA, peel strength and 6X reflow.
– Pb-free HASL: 32%
– Immersion silver: 15%
– Immersion tin: 0%
– RoHS compliant: 21%