GLAST Large Area Telescope Data Acquisition Subsystem

1. Gamma-ray Large Area Space Telescope GLAST Large Area Telescope Data Acquisition Subsystem Electronics, Data Acquisition & Instrument Flight Software Peer Critical Design Review March 19-20, 2003 Nick Virmani Naval Research Lab, Washington DC DAQ EEE Parts Manager nvirmani@swales.com (202) - 767 - 3455

2. Outline • EEE Parts Requirements • EEE Part Implementation Plan • EEE Parts Status • Plastic Encapsulated Microcircuits (PEMs) • Process Flow Chart for ASICs • Process Flow Chart for PEM screening • EEE Parts Concerns • Radiation Testing • Radiation Testing Results

3. EEE Parts Requirements • Requirements Summary • Parts screening and qualification per GSFC 311-INST-001, Level 2, • Additional requirements outlined in the LAT EEE parts program control plan, LAT-MD-00099-1 • Review and approve EEE Part Lists. • Derate EEE Parts per PPL-21 • Review and approve derating information before drawing sign-offs. • Perform stress analysis • Parts Control Board (PCB) Approach, a partnership arrangement with NASA/GSFC parts engineer and code 562. • Part lists are reviewed and approved by the project PCB prior to flight procurements.

4. DAQ EEE Parts Approval Plan • DAQ parts approval process • Parts of DAQ boards are submitted combined, by LAT, into lists organized by part types (C, R, IC, connector, etc) • Contain all parts requested to be used by DAQ engineers • This parts list has been reviewed by the PCB • Second step is to link the approved parts back to the individual assemblies by the LAT (in progress) • Submission of assembly parts-lists containing already approved parts (before CDR) • Advantage is that engineers use as many common and approved parts as possible

5. EEE Parts Status • Resistor – total 93 types of resistors submitted • 91 approved • 2 not approved and require additional screening and testing. • Capacitor – total 70 types of capacitors submitted • 45 approved • 4 require a part number change • 14 are approved with remarks for special procurement clauses • 7 not approved (won’t be used) • Discrete Components – total 18 types of discrete components submitted • 8 approved • 10 not approved, suggested MIL spec part numbers for commercial parts.

6. EEE Parts Status • Integrated Circuit – total 33 types of ICs submitted • 15 approved • 18 not approved yet • Connectors – total 17 types of connectors submitted • 6 approved • 11 require additional screening and qualification as per 311-INST-001. • Actel FPGA’s – total 2 types (54SXA32, 54SXA72) • Approval in progress

7. EEE Parts Status • Discussing EEE parts availability weekly, to support fabrication schedule which includes: • Call manufacturers and suppliers to expedite delivery as required. • Work with test facilities to expedite delivery schedule. • Requires performing 100% incoming inspection. • Stress analysis of all parts on the parts lists yet to be performed. This will be performed after final selection of part types for the required application on the PWB assembly. • Perform screening and qualification tests as required. • Held regular meeting with GSFC Parts Engineer to resolve any parts-related issues and approve parts though the Parts Control Board (PCB). • Attribute data for screening and lot specific qualification/QCI data shall be reviewed for acceptance of parts for flight. • Parts Identification List (PIL) and As-built parts lists is maintained after final selection of parts for PWB assemblies.

8. Plastic Encapsulated Microcircuits (PEMs)(Packaged parts, ASICs, ADC, DAC) • Total 5 types of PEMs used on DAQ boards. • ASICs are fabricated using Agilent processes and packaged by ASAT Hong Kong (QML approved) will be tested, screened, and qualified by SLAC. • ADC and DAC are manufactured by Maxim from a single wafer and assembly lot and parts are fully tested, screened and qualified prior to receipt at SLAC by NRL. • PEM parts will be sample screened (min. 10% of lot size, lot size to be greater than 200 pieces) which includes temperature cycle, initial electrical parameters, dynamic burn-in, final electrical tests which includes static test at +25 degrees C, dynamic and functional at +25 degrees C, and switching test at +25 degrees C, CSAM, and final visual. • Screening data shall be reviewed for use of balance quantity on the lot for flight applications.

9. Plastic Encapsulated Microcircuits (PEMs)(Packaged parts, ASICs, ADC, DAC) • Each screened PEM type will be qual tested which includes DPA, preconditioning, temperature cycling, HAST, CSAM, and electrical test. • Assembled PWB will be subjected to environmental stress screening (ESS) prior to conformal coating, which includes thermal cycling, dynamic burn-in at –30 degrees C to + 85 degrees C, and 100% visual inspection. • All parts will be handled using ESD precautions and will be stored in nitrogen cabinets.

10. Process Flow Chart for ASICs (3 Types) WAFERS RECEIVE FROM MOSIS USING AGILENT PROCESS INSPECTION WAFER MOUNT PROCEDURE WAFER SAW PROCEDURE OPTICAL QC GATE DIE ATTACH ADHESION Scanning Electron Microscope (SEM) Inspection 2ND OPTICAL INSPECTION LEAD FRAME SELECTION CONTROL MONITORS DIE ATTACH CURE WIREBOND WIREBOND MONITOR 3RD OPTICAL QC GATE MOLDING 3RD OPTICAL INSPECTION DIE ATTACH MONITOR

11. Process Flow Chart for ASICs (3 Types) Molding Compound Molding Post Mold Cure Trim Mark Mark Cure Plating Strip Visual Molding Monitor Trim Monitor Mark Monitor Plating Monitor Trays / Tubes CSAM 20 pcs. from lot Form Final Inspection QA Scan Buy-off Dry Bake Inspection Pack Ship to testing facility (NRL/subcontractor) for testing Form Monitor Lead Scan Packing Material Decision for acceptance Final Visual QC Gate

12. PEM (ASICs, ADC, DAC) Screening FlowSingle Wafer Lot and Single Manufacturing Lot LAT instrument requirement Qual –30 degrees C to +50 degrees C, acceptance -20 to 40 degrees C, operational +25 degrees C, Radiation testing TID – 4.5K, SEE immune LET > 37 mev/mg/cm2, Humidity Control 30 to 45%, and 100% GSFC Parts Branch Involvement. 100% screening on 10% of lot size. Lot size should be > 200 pieces, otherwise perform screening on the entire lot. CSAM from sample lot 20 samples for each part type Destructive Physical Analysis. Sample includes radiography 100% Thermal cycle -30 degrees C to 125 degrees C (20 cycles) unpowered 100% Receiving Inspection Prepare test fixtures for burn-in, prepare test programs and verify the functionality of burn-in boards for 10% screening of parts 100% Functional test at room temperature Select samples 10% from this lot and store 90% in N2 purge control room after baking Radiograph (20 pieces) Parts Control Board (PCB) to make decision to use the balance of part i.e., 90% of the parts on the basis of test data review In parallel, select 30 + 22 parts from 10% screened lot for qual. of parts and follow qual. plan, review results when testing is complete Burn-in 168 hours for 10% part at 100 degrees C but do not exceed junction temp. 100% Functional Test and PDA not to exceed 5%

13. PEM (ASICs, ADC, DAC) Screening FlowSingle Wafer Lot and Single Manufacturing Lot Bake 10% screened parts and bag parts in nitrogen purge bags. These parts will be used for rework, repair of assembled boards and for spares only Prior to assembly, verify 100% integrity of fight board and test program, which will be used for testing of assembled board, run verification test on sample assembled boards Survey and select flight qualified assembly house, profile reflow machine and prepare sample flight board. Check the board using test program from previous step Bake 90% flight parts and bag parts in nitrogen purge bags, (only if any of the bags were opened) Assemble flight boards using proven and approved methods. Mandatory inspection points during assembly 100% Inspection of assembled boards 100% electrical verification of flight board using qualified test program 100%, Thermal cycle -30C to 85C on assembled boards, unpowered 100% Dynamic burn-in boards at 85C with continuous monitoring using the same test program Review results, calculate deviations in the parameter from the previous tests 100% Visual Inspection 100% Visual Inspection

14. PEM (ASICs, ADC, DAC) Screening FlowSingle Wafer Lot and Single Manufacturing Lot Perform 100% electrical inspection using the same test program after rework Present data to the Parts Control Board (PCB) (Screening & Qualification) Rework and replace boards, if any, using the screened parts from 10% lot Obtain approval of PCB Perform 100% electrical verification using the same test program Store flight boards in nitrogen purge storage Flight boards ready for next step Conformal coat the boards

15. PEM Qualification on 30 + 22 Parts from Screened Lot • Preconditioning for moisture intake and reflow simulation (30pcs) • Highly Accelerated Stress Test (HAST) (30pcs) • Unbiased HAST – 168 hrs at maximum temperature the part can operate and 85% RH • Electrical Testing at –30 degrees C, +25 degrees C, and +85 degrees C. • C-Mode Scanning Acoustic Microscope (CSAM) as per IPC/JEDEC, J-035 (15pcs). • Destructive Physical Analysis (5pcs) • Operation Life Test • As per MIL-STD-883, method 1005, condition D, 1000 hrs 22 pieces from flight screening lot. • Electrical Testing • Review qualification report and data with Parts Control Board

16. EEE Parts Concerns • ASICs • Packaging of ASICs, screening, and qualification. • Certify subcontractors for packaging, testing, and qualification. • Radiation testing (TID, SEE, and SEU) • ADC & DAC • Screening and qualification of Maxim parts and radiation testing. • To mitigate risk, EM sample parts were evaluated and no anomalies were noticed. • Parts lists yet to be finalized • Derating and stress analysis to be performed after selection of parts for each individual PWB assembly (in progress) • Thermal analysis of PWB to be performed (in progress)

17. Radiation Testing • All EEE parts are being reviewed by PCB and screened for radiation susceptibility against the radiation specification defined in GLAST 433-SPEC-0001 • ASIC radiation testing was performed on similar engineering parts produced using similar processes and materials. • Maxim ADC and DAC were tested and met requirements.

18. Backup

19. EEE Parts Implementation Plan • Part lists are reviewed and approved by the project PCB prior to flight procurements. • Special considerations include: • Radiation evaluation of all active components • Radiation testing (TID and/or SEE ) when necessary • Parts stress analysis • PIND testing on all cavity devices • Destructive Physical Analysis (DPA), when applicable • Pre Cap or sample DPA on semiconductors, microcircuits and hybrids devices as required • Life Testing if Quality Conformance Inspection (QCI) data within one year of the lot being procured is not available • No pure tin, cadmium, and zinc plating is allowed

20. EEE Parts Implementation Plan • Special considerations include cont’d: • 50V ceramic capacitors require 850C/85RHlow voltage testing • Mandatory surge current testing on all tantalum capacitors • Plastic Encapsulated Microcircuits requires special evaluation as outline in the EEE parts plan • Age control requirements. Lot Date Code (LDC) older than 9101 requires DPA and room temperature re-screen • Parts traceability from procurement to assembly of boards. • GIDEP Alerts & NASA Advisories review and disposition • Parts Identification list (PIL) includes LDC, MFR, Radiation information on the flight lot

21. Radiation Testing • SEE Rate and Effects Analysis: • SEE rates and effects shall take place based on threshold LET (LETth) as follows: SEE immune is defined as a device have an LETth > 37 MeV*cm2/mg • Our goal is to test each part type (not previously radiation tested) to the above requirements.