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TEERM COMPLETED PROJECT

Lead-Free Solder Testing for High Reliability (Project 1)

POC: Brian Greene, NASA TEERM Principal Center (321-867-8481)

Background

Solder materials used in assemblies pervade many forms of electronic platforms used by the DoD and NASA.  Therefore, any change in soldering technology will have major implications for military and space operations. 

Such a challenge is now facing the DoD and NASA in the push towards lead-free solder fueled by European environmental legislative actions on the use of lead and increasingly, by commercial and marketing activities overseas.  Lead-free soldering is fast becoming the norm for commercial applications.  Before long, there will be a push for a similar switch to lead-free solder for high-reliability electronics, as is seen in many DoD and NASA applications.

While lead-free solders are purported to reduce environmental and health risks, these solders present certain technical risks.  Of concern, the reliability of most lead-free solders is not well known for high-reliability applications and the adverse environments of earth and space.

A joint partnership, under the auspices of JG-PP and, later, the Joint Council on Aging Aircraft, was formed to tackle the reliability issues surrounding lead-free electronics in high reliability applications.

Objective

The project objective is to generate comprehensive test data on the reliability of circuit cards newly manufactured and reworked with lead-free solder and subjected to simulated high-reliability (IPC Class 3) environmental conditions.

Stakeholders

NASA Centers (Kennedy Space Center, Jet Propulsion Laboratory, Marshall Space Flight Center, Johnson Space Center, Goddard Space Flight Center, Ames Research Laboratory), NASA contractors (United Space Alliance-Solid Rocket Booster, Boeing-Orbiter), major commercial and defense aerospace contractors (BAE Systems, Boeing, Lockheed Martin, Raytheon, Rockwell Collins), Air Force, Army, Navy, Marines, Dept. of Energy and more than 20 other private entities.

Benefits

  • Helps maintain mission readiness by addressing issues related to component obsolescence with lead surface finishes
  • Partnering and substantial in-kind contributions resulted in an estimated 5-to-1 return on NASA’s investment in project.
  • Project’s Joint Test Protocol meets NASA core testing needs (buy-in from key NASA stakeholders).


Achievements

Completed Joint Test Protocol and Potential Alternatives Report. 

  • Completed all short-term testing and published draft Joint Test Report.  Some results and conclusions include:
    • Test vehicles assembled with lead-free materials (notably tin-silver-copper) exhibited lower reliability under some test conditions. This reduced reliability does not necessarily rule out the use of lead-free solder alloy on aerospace and defense electronics in some use environments.
    • Models for calculating the actual field lifetime of lead-free solder joints on certain component types must be developed and validated using actual test data (from this and other studies)
    • Next logical step (besides modeling) is system-level demonstration/validation of promising lead-free solders on functional Class 3 aerospace and defense electronic systems.  This will also help validate any lifetime prediction models for lead-free.
  • Presented data at various major electronics conferences, such as IPC APEX, Joint FAA/DoD/NASA Conference on Aging Aircraft, and SMTA
  • Project won the 2005 Soldertec Lead-Free Solder award
  • Passed on project data to the following organizations for inclusion in their own work products:
    • IPC: Industry standard IPC-9701; Performance Test Methods and Qualification Requirements for Surface Mount Solder Attachments.  In particular, data from the JCAA/JGPP LFS Project will be incorporated into Appendix B of the Guidelines for Thermal Cycle Requirements for Lead Free Solder Joints
    • AIA-ARINC-GEIA Lead-free Electronics in Aerospace Project (LEAP) - GEIA-HB-0005-2 -Technical Guidelines for Aerospace and High Performance Electronic Systems Containing Lead free Solder
    • Lead-free solder interconnect reliability modeling is being conducted by various entities: University of Maryland Computer Aided Life Cycle Engineering (CALCE); Sandia National Laboratories; CirVibe Inc.; DfR Solutions; Electronics Packaging Solutions International Inc.

Joint Test Report (JTR): JTR Executive Summary (JTR Executive Summary - Nov-2009, 3MB, 78 pages, Nov 2009).

Table of Contents:

  1. Introduction. (LFS Website Intro Mar 2005.doc, 36 KB, 2 pages, Mar 2005)
  2. Test Plan Summary. (LFS Website Test Plan Overview Mar 2005.pdf, 277KB, 10 pages, Mar 2005)
  3. Test Board Assembly
    1. Primary Test Board Assembly. BAE Systems. (Phase I Lead free solder 2-22-05.pdf, 7.5 MB, 62 pages, Feb 22, 2005)
    2. Hybrids and CSP Board. BAE Systems. (Phase II Assembly (Hybrids and CSPs).pdf, 1.32 MB, 33 pages, Feb 22, 2005)
    3. Assembly Details:
      1. Component Types and Finishes (Table below):

        Component types and Finishes

      2. JCAA/JG-PP Test Vehicle Types (Table below):

        Test Vehicle Types

      3. Component Solder Key: Details on specific component finishes and solder alloys used for each component on "Manufactured" and "Rework" test vehicles. (Component_Solder Key.pdf, 18KB, 4 pages, March 2006)
  4. Discussion of Test Results.
    1. Vibration Test. Boeing Phantom Works. (VibEMP Rev. A 010906.pdf, 7.71MB, 303 pages,  Jan 09, 2006)
      1. Micro Section Photos. (Vibe.xls., 31.8MB, 47 pages, Aug 18, 2005).
    2. Thermal Shock Test. Boeing Phantom Works. (ThShockEMP Rev. A.pdf, 4MB, 105 pages, Mar 01, 2006)
    3. Thermal Cycling Test -20 to +80 deg. C. Boeing Phantom Works (WoodrowThCycleEMP Final formatted for print.pdf, 2,104KB, 68 pages, Oct 31, 2008).
    4. Thermal Cycling Test -55 to +125 deg. C. Rockwell Collins (Rockwell Collins Inc JCAA JGPP Final Report neg55C to pos125C testing Rev B.pdf, 2MB, 74 pages,  May 28, 2006)
      1. Final Report for the CSP, Hybrid & SMT Resistor/Capacitor Components Rockwell Collins (Rockwell Collins Inc JCAA JGPP CSP-Hybrid Final Report -55C to +125C testing Rev D.pdf, 33 pages, 6MB, June 2007)
    5. Combined Environments Test. Raytheon. (Combined Environments Test Report - Final.pdf, 4 MB, 128 pages, Aug 15, 2005)
      1. Combined Environments Test Failure Analysis (ITB Report 3.pdf, 15MB, 116 pages, Jan 31, 2006).
    6. Mechanical Shock Test. ACI. (JG-PP LEAD-FREE Solder Final Report finalized 061506.doc, 10.5MB, 58 pages, Jun 20, 2006)
    7. Salt Fog and Humidity Tests. ACI. (ITB 01366R1a-080305.pdf, 2MB, 16 pages, Aug 11, 2005)
    8. Surface Insulation Resistance and Electrochemical Migration Resistance Tests
      1. Electro-chemical Migration Resist`ance (EMR)/Surface Insulation Resistance (SIR) Final Report. Boeing-Anaheim. (TR05_01EMRSIR.doc, 1.21MB, 11 pages, Mar 21, 2005)
      2. Rev. B – EMR & SIR Test Results. Boeing-Anaheim. (JGGPEMRSIR(revB).pdf, 1.07MB, 30 pages,  Dec 14, 2004)
      3. Rev. A - SIR Test Results - Updated (JGGPSIR(reva).pdf, 249KB, 13 pages,  Jan 17, 2005)
  5. Additional Resources.
    1. Dave Hillman CMAP Paper. Presented at the March 16, 2005 LFS Project Meeting. Rockwell Collins. (CMAP paper Rev A.pdf, 1.55MB, 9 pages, Mar 11, 2005) 
  6. Manufactured Test Vehicle Characterization
    1. PWB 41. Manufactured Board (Control): SnPb Reflow Paste & SnPb Wave Solder. Rockwell Collins. (PWB41-SnPb-As Manufactured.pdf, 27.2MB, July 6, 2005)
    2. PWB 110. Manufactured Board: Sn3.9Ag0.6Cu Reflow Paste & Sn3.9Ag0.6Cu Wave Solder. Rockwell Collins (PWB110 SAC as manufactured.pdf, 15MB, July 12, 2005)
    3. PWB 111. Manufactured Board: Sn3.4Ag1.0Cu3.3Bi Reflow Paste & Sn0.7Cu(~0.05Ni) Wave Solder. Rockwell Collins. (PWB111 SACB as manufactured.pdf, 14MB, July 6, 2005)
    4. Vibration Micro-Section Photos (Vibration Micro-Section Photos.pdf, 12MB,  Aug 3, 2007)
  7. Component Characterization

  8. Failure Analysis
    1. Failure Analysis Report (Failure Analysis Report 103106.pdf, 518KB, 9 pages, Oct. 25, 2006)
      1. Mechanical Shock Photos, Aug 3, 2007 (slideshow)
      2. Thermal Shock Photos, Aug 3, 2007 (slideshow)
      3. Vibration Photos,  Aug 3, 2007 (slideshow)
  9. Follow-On Project Proposals
    1. NASA Lead-Free Electronics draft proposal (Draft-NLFE Proposal January-22-2007.pdf, 279 KB, 25 pages, Jan. 22, 2007)
  10. Modeling
    1. JCAA/JG-PP Lead-Free Solder Project: Vibration Test, Solder Comparison by Component Level Life-Use Analysis John E. Starr, CirVibe Inc.  (Solder Comparison by Component Level Life_Use Analysis_Final.pdf, 373KB, 25 pages, July 10, 2006)
    2. Assessment of Pb-Free Norris-Landzberg Model to JG-PP Test Data, Craig Hillman, DfR Solutions (JG-PP and NL Model Analysis II.pdf, 82KB, 14 pages, Feb. 21, 2006)
    3. Vibration Durability Investigation for SAC and SnPb Solder, CALCE (JGPP report_final_10_25_2006 (2)_.pdf, 2MB, 20 pages, Oct. 25, 2006)
    4. Strain Range Approximation for Estimating Fatigue Life of Lead-free Solder Interconnects Under Temperature Cycle Loading, CALCE (CALCEJGPPTCPaper.pdf, 328.1KB, 10 pages, Dec. 2006)
    5. Modeling of the JCAA/JG-PP Lead-Free Solder Project Vibration Test Data, Boeing Phantom Works. (WoodrowVibBoston2007Rev.F.pdf, 939KB, 24 pages, April 2007)