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.3.5.1.3 Subsurface imperfections................................................................................................................ 14

A.3.5.1.3.1 Foreign inclusions..................................................................................................................... 14

A.3.5.1.3.2 Foreign inclusions between printed board surface and stiffener............................................... 15

A.3.5.1.3.3 Subsurface spots...................................................................................................................... 15

A.3.5.1.3.4 Adhesive voids ......................................................................................................................... 15

A.3.5.1.3.5 Measling and crazing................................................................................................................ 15

A.3.5.1.3.6 Exposed or disrupted reinforcement fibers ............................................................................... 15

A.3.5.2 Conductor pattern .................................................................................................................................. 15

A.3.5.2.1 Bonding of conductor to base material and lifted lands................................................................... 15

A.3.5.2.2 Conductor finish .............................................................................................................................. 15

A.3.5.2.2.1 Coverage .................................................................................................................................. 16

A.3.5.2.2.1.1 Dewetting ........................................................................................................................... 16

A.3.5.2.2.1.2 Nonwetting ......................................................................................................................... 16

A.3.5.2.2.2 Conductor finish plating and coating voids in plated-through holes .......................................... 16

A.3.5.2.2.3 Edge board contacts................................................................................................................. 16

A.3.5.2.2.4 Plating junctions ....................................................................................................................... 16

A.3.5.2.2.5 Solder mask.............................................................................................................................. 16

A.3.5.2.2.6 Whiskers................................................................................................................................... 16

A.3.5.2.3 Conductor pattern imperfections ..................................................................................................... 17

A.3.5.2.3.1 Cuts and scratches ................................................................................................................... 17

A.3.5.2.3.2 Dents ........................................................................................................................................ 17

A.3.5.2.3.3 Pinholes.................................................................................................................................... 17

A.3.5.2.3.4 Pits ........................................................................................................................................... 17

A.3.5.2.3.5 Superfluous metal..................................................................................................................... 17

A.3.5.2.4 Conductor spacing and width .......................................................................................................... 17

A.3.5.2.4.1 Conductor spacing.................................................................................................................... 17

A.3.5.2.4.2 Conductor width........................................................................................................................ 17

A.3.5.2.5 Component mounting ...................................................................................................................... 17

A.3.5.2.5.1 Annular ring, external ............................................................................................................... 17

A.3.5.2.5.2 Rectangular surface mount lands ............................................................................................. 18

A.3.5.2.5.3 Round surface mount lands and Ball Grid Array pads .............................................................. 18

A.3.5.2.5.4 Wire bond pads ........................................................................................................................ 18

A.3.5.2.6 Holes for interlayer connections ...................................................................................................... 18

A.3.5.2.7 Registration, external (method I) ..................................................................................................... 18

A.3.5.2.7.1 Component hole lands.............................................................................................................. 18

A.3.5.2.7.2 Rectangular surface mount lands ............................................................................................. 18

A.3.5.2.7.3 Round surface mount lands...................................................................................................... 18

A.3.5.3 Coverlayer ............................................................................................................................................. 19

A.3.5.3.1 Coverage ........................................................................................................................................ 19

A.3.5.3.2 Delamination ................................................................................................................................... 19

A.3.5.3.2.1 Wrinkles or creases .................................................................................................................. 20

A.3.5.3.2.2 Continuous flex designs ........................................................................................................... 20

A.3.5.3.3 Cover coat cure............................................................................................................................... 20

A.3.5.3.4 Registration ..................................................................................................................................... 20

A.3.5.3.5 Thickness ........................................................................................................................................ 21

A.3.5.3.6 Wicking of metallic conductor surface finish materials .................................................................... 21

A.3.5.4 Dimensions of features .......................................................................................................................... 21

A.3.5.4.1 Conductor pattern feature accuracy ................................................................................................ 21

A.3.5.4.2 Hole pattern accuracy ..................................................................................................................... 21