1 Coupon Evaluation for GSFC Flight PWBs presented by Diane Kolos Materials Engineering Branch NASA Goddard Space Flight Center November 14, 2007

2 Introduction Coupon as an Indicator of Board Quality –A coupon is representative sample of the printed circuit board (PCB) designed for destructive analysis. It is produced on the same manufacturing panel with the PCB and has experienced all of the production processes with the board it represents. –The coupon is our best tool for determining the acceptability of flight PCBs. Failure rate as a function of coupon analysis: –26% in % today –These rejections are after vendor coupon screening

3 Significant Trigger Events Instrument failure at launch site On-orbit failure of device $4 million replacement of 148 boards on one S/C Alert against major independent coupon laboratory

4 Coupon Testing Basics Cross-sectioning technique –GSFC uses 5 grinding steps and 3 polishing slurries to prepare coupons –Sample preparation is critical to identification of defects Trace to barrel joints are copper and easily smeared Thermal Stress Testing 550F for 10 seconds

5 GSFC Policies for PCB Procurement Require coupon evaluation for every flight board –Includes double sided product Applicable Specifications –Rigid boards 6012B Class 3/A Uses Performance Specification Sheet for Space & Military Avionics –Flex boards 6013B Must be done at GSFC or a GSFC-approved lab

6 Coupon Failures

7 Missing Plating in Through Hole

8 Missing Annular Rings at Buried Via

9 Gross Plating Folds in Through Hole

10 Missing External Annular Ring

11 Inadequate Internal Annular Rings

12 Missing Cap Plating

13 Trace to Barrel Separations

14 Laminate Defect

15 Laminate Defect

16 Contact Information Diane Kolos (301) Rita Rozenbaum (301)