MIL-PRF-50884 Printed Wiring Board, Flexible Or Rigid-Flex, General Specification ForThis specification establishes the performance and qualification requirements for flexible and rigid-flex printed wiring boards with or without plated through holes \(see 6.1\). Verification is accomplished through the use of one of two methods of product assurance \(appendix A or appendix B\). Detail requirements, specific characteristics, and other provisions which are sensitive to the particular intended use are specified in the applicable master drawing.

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MIL�PRF�50884F

CONTENTS

PARAGRAPH

PAGE

A.3.6.4 Plated-through hole plating.................................................................................................................... 28

A.3.6.4.1 Copper plating thickness ................................................................................................................. 28

A.3.6.4.2 Wrap copper plating ........................................................................................................................ 28

A.3.6.4.3 Copper plating defects .................................................................................................................... 29

A.3.6.4.4 Copper plating voids ....................................................................................................................... 29

A.3.6.4.5 Wicking of copper plating ................................................................................................................ 29

A.3.6.5 Conductive interface separations........................................................................................................... 29

A.3.6.5.1 Copper to copper interfaces ............................................................................................................ 29

A.3.6.6 Via cap plating ....................................................................................................................................... 29

A.3.6.6.1 Thickness ........................................................................................................................................ 29

A.3.6.6.2 Cap plating imperfections................................................................................................................ 29

A.3.6.7 Hole wall deficiencies ............................................................................................................................ 30

A.3.6.8 Metallic cracks ....................................................................................................................................... 30

A.3.6.9 Nail-heading .......................................................................................................................................... 30

A.3.7 Inspection requirements............................................................................................................................... 30

A.3.7.1 External visual and dimensional acceptability........................................................................................ 30

A.3.7.2 Destructive physical analysis by metallographic evaluation of printed wiring board test specimens ..... 30

A.3.7.2.1 Non-stressed specimens................................................................................................................. 30

A.3.7.2.2 Registration, internal ....................................................................................................................... 30

A.3.7.2.2.1 By microsection (method II) ...................................................................................................... 30

A.3.7.2.2.2 By registration test coupons (method III) .................................................................................. 30

A.3.7.3 Chemical requirements.......................................................................................................................... 31

A.3.7.3.1 Ionic contamination ......................................................................................................................... 31

A.3.7.3.1.1 Prior to the application of solder mask...................................................................................... 31

A.3.7.3.1.2 Completed inner layer prior to lamination ................................................................................. 31

A.3.7.3.1.3 Completed printed wiring boards .............................................................................................. 31

A.3.7.3.2 Resistance to solvents .................................................................................................................... 31

A.3.7.4 Physical requirements ........................................................................................................................... 31

A.3.7.4.1 Adhesion, coverlayer....................................................................................................................... 31

A.3.7.4.2 Adhesion, legend and marking........................................................................................................ 31

A.3.7.4.3 Adhesion, plating............................................................................................................................. 31

A.3.7.4.4 Adhesion, solder mask.................................................................................................................... 32

A.3.7.4.5 Bow and twist .................................................................................................................................. 32

A.3.7.4.6 Flexibility endurance ....................................................................................................................... 32

A.3.7.4.6.1 Qualification and periodic testing .......................................................................................... 32

A.3.7.4.6.2 User specified ....................................................................................................................... 32

A.3.7.4.7 Folding flexibility.............................................................................................................................. 32

A.3.7.4.7.1 Qualification and periodic testing.............................................................................................. 32

A.3.7.4.7.2 User specified........................................................................................................................... 32

A.3.7.4.8 Rework simulation........................................................................................................................... 33

A.3.7.4.8.1 Grade R, types 1 and 5 with unsupported holes....................................................................... 33

A.3.7.4.8.2 Grade R, types 2, 3 and 4 with plated-through holes................................................................ 33

A.3.7.4.8.3 Grade U .................................................................................................................................... 33

A.3.7.4.9 Solderability..................................................................................................................................... 33

A.3.7.4.9.1 Hole solderability ...................................................................................................................... 33

A.3.7.4.9.2 Surface solderability ................................................................................................................. 33

A.3.7.4.10 Solder mask cure .......................................................................................................................... 33

A.3.7.4.11 Surface peel strength .................................................................................................................... 33

A.3.7.5 Electrical requirements .......................................................................................................................... 34

A.3.7.5.1 Circuit continuity and shorts ............................................................................................................ 34

A.3.7.5.1.1 Circuit continuity ....................................................................................................................... 34

A.3.7.5.1.2 Circuit shorts............................................................................................................................. 34

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