Enabling COTS Parts Insertion in NASA Systems: A Combined NEPAG Q, AE NEPP Program AE Activity

1. Enabling COTS Parts Insertion in NASA Systems:A Combined NEPAG (Q, AE) � NEPP Program (AE) Activity Chuck BarnesNEPP Program ManagerJet Propulsion LaboratoryCalifornia Institute of TechnologyPasadena, CA and Mike SampsonNEPAG Program ManagerNASA Goddard Space Flight CenterGreenbelt, MD NASA S&MA Directors� MeetingDryden Flight Research CenterOctober 10, 2002

2. Outline NEPAG and NEPP Objectives and Organization NEPAG and NEPP Relationship Use of commercial off-the-shelf parts in space NEPAG/NEPP COTS Evaluation Activity Approach Upscreen Flow Results Glass Transition Temperature Results Breakdown Voltage C-Mode Scanning Acoustic Microscopy (C-SAM) Results Conclusions

3. NEPAG Charter and Objectives Charter Provide knowledge, tools, information and resources to aid project EEE parts engineers and parts specialists in guiding parts selection decisions by designers and projects Promote quality and reliability assurance processes to eliminate EEE part failures from the advanced stages of the project life-cycle Objectives Reduce incidence of EEE parts failure through Establishing an inter-agency working group of parts engineers from NASA Centers and JPL for agency-wide coordination of parts issues Developing information technology-based communication system and tools to increase efficiency Creating a knowledge-base of part supplier quality Developing assurance tools for COTS parts Maintaining a current NASA EEE parts selection list (NPSL) Influencing non-government and government standards bodies

5. NASA Electronic Parts and Packaging (NEPP) Program Program Objectives Assess the reliability of newly available commercial off-the-shelf (COTS) electronic parts and packaging technologies Evaluate advanced and emerging parts and packaging technologies to expedite their readiness for infusion in NASA systems Develop new methods and processes for parts and packaging evaluation, selection, and qualification. Disseminate quality assurance, reliability, radiation tolerance, validation, tools and availability information to the NASA community Program Features $9.4M/yr Program funded by the NASA Chief Engineer�s Office (Code AE) Multi-Center Program - 80 to 85% of work at JPL and GSFC JPL is coordinating Center Program focus on TRL 3 to 6 Collaborations with DoD, Industry and Academia Program content determined by both a proposal review process and by strategic shaping Program made up of 4 projects � Parts Project, Packaging Project, Electronics Radiation Characterization Project and Information Management and Dissemination Project Program focus is from individual part/component up to board level

6. NEPP Program Organization

7. Relationship of NEPAG and NEPP

8. Reasons for COTS Use in Space Large, standardized software base �Lower� cost, �quicker� delivery Although upscreening can stretch delivery and raise cost substantially Parts are small fraction of total satellite/spacecraft cost (5 to 10%), but this cost will be relatively higher in future Rad-hard processing lines that do exist are 1 to 2 generations behind Greater government reliance on industry standards and specifications for part procurement (Perry Directive) For NASA, paradigm of �Better, Faster, Cheaper� allows for risk management at system level, rather than complete elimination of risk, and requires quick, inexpensive procurements Access to high performance, state-of-the-art microelectronics

9. Relative Size of Space Market for Microelectronics

10. Problems with Use of COTS in Space Life cycle costs can actually be higher for COTS-intensive spacecraft due to added testing, part and system failure, system re-work, added cost of shielding Reliability data on COTS is often unknown or unavailable to small customers Lot traceability is often impossible with devices from the �same� lot that are actually made on different fabrication lines Process changes unknown to the customer can result in reduced reliability and radiation tolerance Variations between lots over time can nullify the validity of testing performed on a lot prior to purchase of a flight lot Even for parts with satisfactory reliability and radiation tolerance, packaging can cause problems in the space environment Simple passives - capacitors, resistors - can cause failures on the board or internal to hybrids Recent experiences with DC-to-DC converters Commercial competitiveness to reduce cost, improve performance can jeopardize availability of specific parts required in future systems Space applications do not usually allow for repair or replacement Hubble Space Telescope, Shuttle and International Space Station are exceptions Radiation degradation can�t be solved by leveraging off other high-reliability, high volume users (automotive industry)

11. Enabling COTS Parts Insertion in NASA Systems:NEPAG/NEPP COTS Evaluation Activity NEPAG and NEPP are working together to evaluate the practical and technical issues surrounding use of COTS in NASA systems Practical issues Surveys of test houses (capabilities, handling procedures etc.) Surveys of distributors (how do they do business?) Visits to manufacturers (how do they collect their data?) Cost/benefit comparison for typical screens and qualification Tests Proper and effective oversight/insight into vendors, distributors and test houses Technical issues Validation of vendor part technical data Analysis of upscreening steps and philosophy for added value in the NASA environment Detailed investigation of selected upscreening steps and failure mechanisms revealed by these steps Objectives Establish guidelines for how/if NASA can reliably select/test/apply Commercial-Off-The-Shelf (COTS) and Plastic Encapsulated Microcircuits (PEMs) Establish methods for assessing the validity/applicability of vendor supplied qualification/test data for COTS/PEMS technologies Determine appropriate upscreening flows for NASA applications

12. NASA Unique Approach The NEPAG/NEPP approach to evaluating COTS and upscreening for space is unique compared to other studies in that we will Gather a complete data set on the same sample of COTS devices, using established methods to measure the assembly, materials, design, performance, and reliability attributes Provide detailed evaluation of upscreening steps and their added value or lack thereof, and the failure mechanisms mitigated by these steps Assess robustness of parts evaluated by drawing any correlations between any failures (or lack thereof) and the inherent manufacturer�s advertised quality and reliability Establish NASA guidelines for using COTS in space applications, utilizing a risk posture approach for different critical and non-critical missions and then making recommendations on how to mitigate the risk according to the mission requirements

13. NEPP/NEPAG COTS Evaluation Approach NEPAG is focusing on passives (capacitors, resistors) while NEPP is concentrating on active microcircuits Team approach used for major decisions and tracking Establish NEPAG/NEPP team for deciding on major task steps, parts selection, test house selection, upscreening flow details Representatives from: GSFC, JPL, ARC, GRC, JSC, KSC, LaRC, MSFC, USAF, Aerospace Corp., TRW, APL, NAVSEA, ESA, NASDA Tracking teams for test houses and data established for passives and actives Procure devices for evaluation based upon actual NASA program needs Passives are Base Metal Electrode (BME) ceramic chip capacitors 0805 and 0402 Chip Sizes 6.3 V to 50 V Ratings Four Different Manufacturers (+ 2 High Rel Suppliers) Actives are all plastic encapsulated microcircuits (PEMs) 8-bit high speed, low power Analog/Digital Converter (ADC1175) � Device spares already requested by a flight project 16 channel analog multiplexer (MAX306) High speed operational amplifier (LT1468) High precision voltage reference (AD780) High common mode voltage difference amplifier (INA117) Survey manufacturers and review �internal� qualification process and test data Subject selected devices to extensive screening/qualification/evaluation test protocol as an �independent� verification of the vendor�s qualification and to determine added value of individual screening steps Publish results in the form of a NASA Guideline Document for Proper Selection & Qualification Methodology for COTS/PEMS devices

14. Outline of PEMs Upscreening Test Flow

15. NEPP/NEPAG COTS Evaluation Phase 1 status Two active and two passive device manufacturers visited/surveyed Some vendors allow communication only through distributors As indicated on title page, �Lots� may be mixes from various lines/locations Big problem for high reliability, radiation tolerant applications such as NASA flight systems Vendor data reviewed Life testing is done on high runners (mature parts) Data exclusion rules used to stop �freak� lots from upsetting failure-in-time (FIT) calculations Sample quantity, test duration, test conditions and frequency of testing vary widely between vendors Sampling (or not) from lines, locations, wafer fabs or package styles can be random Published FIT values applicability to procured product is vendor and part type dependent and may be unknown NEPP/NEPAG screening/qualification testing in progress Several test houses were visited and two were selected for actives, one for passives Selection process mimics what flight project would do Identify problems with test houses � already demonstrated value of having regular onsite inspections of work Actives Destructive Physical Analyses (DPAs) have been completed Initial electrical characteristics look good but data have not been analyzed in detail PEMs encapsulant glass transition temperatures vary widely and do not always agree with vendor data Passives (capacitors) One lot failed to meet dissipation factor limit during initial electricals One DPA lot showed a proportionally large delamination

16. Measurement of PEM Glass Transition Temperature

17. Features/Issues for Tg Results on Five Microcircuits Each sample is from a different manufacturer The Glass Transition Temperature (Tg) values vary more than was anticipated according to vendor data One manufacturer expressed surprise at the low value as their policy was to control Tg to >160C 117C is below the standard burn-in and test temperature NASA often uses for space parts � 125C and the Tg we desire of 145C which provides a 20C margin to the burn-in The high thermal expansion above the Tg value raises reliability concerns such as: Excessive stress on wire bonds Delamination between encapsulant and lead frame or die paddle Excessive stress on the die Other reliability concerns when transition temperature is exceeded are CTE of epoxy encapsulant will permanently change (breakdown of chemical cross-linking of polymers) Displacement of wire bonds resulting in a premature wear-out and breakage of wires Premature aging (e.g. storage) Induced stresses between materials internal/external) because of CTE mismatch; reduces temp. cycling capability Adhesion degradation Release of Bromine, Red Phosphorous (flame retardants); can cause corrosion, lifted bonds due to release of ionics) Device performance degradation

18. COTS Capacitor Tests � Breakdown Voltage vs. Dielectric Thickness

19. Additional Recent Results DPA Results Contrary to the vendor�s website advertisement, pure tin was found on two device types of the five being tested (this is a prohibited material for NASA applications) Contrary to the vendor�s website advertisement, glass transition temperatures for the epoxy compound on two device types were below the industry norm As noted earlier, this can cause reliability problems Unplated areas of base lead frame metal (can lead to corrosion, oxidation, etc.) One device used steel as the base material for the lead frame as opposed to alloy 42 and copper materials normally used by most vendors Screening Results Significant value has been demonstrated for having regular onsite NASA oversight/insight into testing For one device type, 500 parts were procured from distributor Three different date codes were supplied Electrical verification to the vendor�s data sheet advertised limits showed two date codes met the limits, while one date code experienced 16 failures out of 250 tested C-Mode (horizontal scan) Scanning Acoustic Microscopy (C-SAM) Inspections One device type has completed CSAM tests Results show all 250 devices have delamination problems which exceeds industry acceptable standards >10% delamination is unacceptable

20. NEPAG/NEPP ADC1175CIJM C-SAM Accept and Reject Examples

21. Conclusions Early results already show that vendor data cannot always be trusted Observed low glass transition temperature results suggest potential severe reliability problems especially for use of burn-in to eliminate bad parts Multiple date codes within a lot buy have demonstrated significant variations in quality and reliability Capacitor voltage breakdown data has shown variations from one manufacturer to another that may result in reliability problems C-SAM results show extensive delamination problems Important result from the point of view of test value since C-SAM has been controversial in terms of its value added These results are from very early analysis of test results and we expect additional significant insights into the upscreening process for COTS parts