SMART Events

The 5th Annual SMART Group Lead-Free Seminar and exhibition, held at Nattional Physical Laboratories new conference facility, sold out all 128 delegate spaces and a questionnaire carried out during the day confirmed that the industry, whether large or small companies, do not have a plan in place for lead-free introduction.

During the seminar 82 participants contributed to a survey covering all aspects of lead-free implementation. The survey was organised by Bob Willis, the Technical Director of SMART and chairperson for the day. The results are published for members and some of the results were surprising.

Both small, medium and large companies do not have a complete plan in place for lead-free introduction. There was a great deal of interest 3-4 years ago when the subject of a lead-free ban was first mooted, including an excellent report published by DTI and launched by SMART at the Nepcon show. However, most engineers moved on to more pressing matters, including trying to keep their company afloat during this continuing recession. Now that a date has been set for the banning of lead, engineers are flocking back to gain knowledge of the challenges ahead.

The survey was completed by 50 OEMs, 14 CEMs and 18 material & equipment suppliers. The majority of the companies represented at the event were large companies of over 250 staff, with only 3 representatives from small companies of less than 50 people. The majority of all the companies were from either consumer, military or telecoms markets.

As far as alloy selection is concerned, 27 believe they will be using Sn/Ag/Cu for reflow, wave and hand soldering, but 45 are still reviewing literature and various reports on alternatives. The surface finish for printed circuit boards, preferred by 28 delegates, was indicated to be gold over nickel. Lead-free solder levelling and silver and tin are possible options. The majority, 48, did not know what finish they would be using for component terminations, this is despite information being readily available from lead-free component suppliers.

The reliability concerns included voiding, the possible need to clean and unknowns on fine pitch PCB designs. Many responded (28) that they did not know what they should be specifying in terms of component peak temperature, with 16 feeling that 260 degrees C would be a maximum requirement.

It was interesting to see that 17 companies were considering the use of nitrogen for reflow and 8 for wave soldering. The majority were aware of the benefits that nitrogen could provide for reflow.

The services that SMART Group can offer were voted equally as being needed, including a regularly lead-free forum, hands on workshops, process information sheets, regular updates on technical papers and reports, on site audits and a special lead-free help desk. SMART intends to hold a follow up day, with practical hands- on, as early as May 29th.

Now is the time for British Electronics Industry to pull together to meet the challenge ahead. It was good to see two representatives of DTI contributing in this event, Nick Jolly taking some of the questions at the end of the day. The SMART Group and NPL certainly will be offering all the help they can.

It is clear that the lead-free snowball is now rolling.

The seminar papers covered the following subjects:

1st July 2006 - The end for lead soldering
Steven Andrews, Recycling Policy Unit Sustainable Development Directorate, DTI Department of Trade and Industry.

Steve will provide the latest details of the plans for the UK implementation of the European Restriction of the use of certain Hazardous Substances (RoHS) Directive.

Assessment of the published reliability data for lead-free solder
Malcolm Warrick & Hector Steen, Multicore product development at Loctite Electronics.

This paper briefly review the published information comparing the performance of lead-free soldered joints with conventional tin/lead connections. It will look at the accelerated test methods used and the interpretation of results in the context of possible failure mechanisms and microstructural changes. The dangers of extrapolating results from accelerated test to real life conditions will be discussed.

A copy of the papers from the seminar are available in the SMART Group Members Area. To become a member of the SMART Group click here www.smartgroup.org/form_joingroup.asp

Lead Free Seminar Speakers at the NPL and SMART Group Event

Reliability issues, solder joints and laminates
Alan Brewin NPL

Solder joint degradation is by thermal-mechanical fatigue. Experiments and modeling are conducted that attempt to predict service life, the data this can produce is reviewed. The second key aspect of circuit reliability is the effect of flux residues and other extraneous sources of contamination in insulation performance. The main tool to evaluate reliability is the measurement of insulation resistance, both surface, and also sub-surface in the case of CAF growth in multi-layer boards.

User induced component failures and the transition to lead-free
Angus Westwater, Rohm Components

The presentation is focused into two sections. Firstly looking at the reliability of solder joints where lead-free component plating are introduced to existing leaded solder processes and where leaded component plating continues to be used where the solder has been changed to lead-free. The presentation supports the strategy to change to a lead-free process and modify process parameters when and only when all components are lead-free. Secondly, review of PCB assembly and test introduced component failures. These failures include mechanical damage, thermally introduced damage and electrical overload including ESD images and trends towards miniaturisation of bipolar devices making them more sensitive to ESD damage.

Lead-Free component issues
Chris Hunt, NPL

With the widening interest and need to implement a lead-free process there has been much discussion and speculation on the stability of electronics components. In this study a range of components were selected and their functional and physical stability during lead-free reflow conditions assessed. Industry concerns about lead-free soldering with these component types are addressed in light of the results.

Implementing Pb-free solder paste in mobile phone production
Steve Dowds, Indium Corporation

Essentially this paper uses data from Motorola to show how solder pastes should be evaluated and how Pb-free is implemented in production. It gives a distillation of 3 years-worth of data and 15 months of full scale production experience, outlining some of the pitfalls and how to avoid them.

Die attach at 260C in a Pb-free environment
Mike Butler, Henkel-Loctite

The elevated temperatures of lead-free soldering place severe stress on the adhesives used, within packages and on boards. Traditional Epoxy chemistry is unable to cope well in this environment. Suppliers are having to find new materials able to perform in the lead-free process.

A copy of the papers from the seminar are available in the SMART Group Members Area click here