Reliability During RoHS Transition
Like the rest of the electronics industry, your products will transition to Restriction of Hazardous Substances (RoHS) compliance prior to the deadlines in 2006. This includes the transition to Lead-Free Solder, and at this time, there are significant reliability uncertainties around Lead-Free Solder. Even if your product does not need to be compliant, the materials and processes that make up your product are changing. As one major consumer product team concluded, doing nothing would double the field failure rate of the electronics. Given limited resources, you and your team may not have the time or expertise to determine the areas of greatest risk and how best to manage the transition. Leveraging our experience with RoHS related failure mechanisms, we help companies in the following ways:
NEAR TERM (BEFORE TRANSITION)
- Help determine when to transition (scenario planning/risk analysis)
- Analyze mixed technologies (Lead-free components mixed with Leaded solder)
- Obtain supplier data/review for RoHS compliance
LONGER TERM (DURING TRANSITION)
- Mitigate Reliability risks during transition
- Set new metrics and develop implementation plans
- Review Supplier Information. Interpret data and vendor reports
- Work with vendors on issues during transition
- Create qualification plans to assure no compromise in reliability
- Develop manufacturing screens to assure no compromise in outgoing quality
- Work with your Contract Manufacturer(s) to assure a reliable transition
We typically break down an RoHS implementation project into four phases.
Phase 1: Reliability Assessment
Phase 2: RoHS Qualification Test Plan
Phase 3: Executing the RoHS Test Plan
Phase 4: RoHS Training
Phase 1: Reliability Assessment
We start with a Reliability Assessment. In the assessment process, we will do the following:
1) Assess where you stand today in terms of compliance
2) If you are not in compliance, we will determine what you need to do to get in compliance
3) Determine what product qualification tests you need to run to assure a reliable product
As part of the assessment process, we will review the following 3 areas:
Task 1: Review of Bill of Materials
How are you ensuring RoHS compliant components? Is there a more effective (lower cost, quicker) approach?
Task 2: DfM Review
- Is the current design manufacturable, in regards to Pb-free?
- How are you developing profiles for reflow and wave soldering?
- How are you revising rework procedures? Is it sufficient?
- Have you chosen the appropriate board plating, considering product complexity, volumes, and manufacturing schedules?
Task 3: DfR Review
- Given the product design, what are the major issues in regards to the transition to Pb-free? Where should you focus your resources?
- What product qualification procedures should be performed to ensure at least equivalent robustness to a eutectic design?
- What, if any, additional process controls should be implemented to minimize the occurrence of latent defects?
The entire assessment portion of the project only takes a few days. This information is then compiled into an Assessment Report with Recommendations on an implementation strategy and schedule.
See the illustration below for a comparison of Stress vs.Time when Temperaturing Cycling Eutectic (SnPb) and Pb-Free Solder. For certain temperature cycles, Pb-Free is more reliable and for other types of temperature cycles, SnPb is more reliable. This is why there is a need to carefully review the new processes and materials within your current environment to evaluate any possible risks.
Phase 2:RoHS Qualification Test Plan
The RoHS Qualification Test Plan shall address some or all of the following Reliability Risks:
- Higher reflow temperatures
- Solderability and wetting
- Solder joint durability (Temperature cycling tests)
- Solder brittleness
- Component package compatibility due to thermal mismatch stresses (i.e. ceramic capacitors)
- Shock loading (high forces during industrial usage conditions).
- Moisture ingression ("pop-corning")
- Solder voids due to inter-metallic contamination
- More aggressive fluxes
- Tin whiskers
- PCB FR4 construction
As part of writing the test plan, we will understand your product, shipping and operating environment and narrow down the issues to those that present a significant change in reliability risk. Then we will use our knowledge of industry activities, reported results, and recommendations to create the customer-specific RoHS Test Plan. We will incorporate existing test and evaluation activities wherever possible and use other cost effect and efficient methods.
The deliverable is a Detailed Test Plan with rationale on why each test was chosen.
Phase 3:Executing the RoHS Test Plan
We can then help with the execution of the RoHS Test Plan, including participating in the tests, analyzing the data, and helping to draw conclusions from the data. We have relationships with many different labs that can help carry out any or all of these tests.
Phase 4:RoHS Training
We can then put together and give a training course to educate key personnel within your organization about the issues at hand.
We shall tailor our on-site training for RoHS awareness and engineering challenges to meet your specific needs. Included shall be a brief overview of corporate-wide RoHS programs, policy and timelines; connections to your products and external sources for more information; and, specific design, materials and manufacturing related areas of concern. The intent is to provide enough awareness to alert engineers to investigate decisions on designs, ECO's and component selection to maintain or enhance RoHS compliance in-line with your company's policies.
Using this four-phased process, we can help you proactively manage this change and protect your reputation.
We shall be part of a 6 city panel national panel discussion tour on RoHS/WEEE starting in October (see Events above for details on dates). Please visit the following site for more details: www.aspmfg.com. This will be a similar format to the RoHS/WEEE Panel of Experts held on July 26th. Please visit the following site for more details: RoHS Panel Discussion.