IPC standards committee reports: materials, boards, embedded, flex

This is part of a series of updates from IPC standards committee meetings at IPC Midwest.

Base Materials

The 3-11 Laminate/Prepreg Materials Subcommittee worked on amending IPC-4101C, Specification for Base Materials for Rigid and Multilayer Printed Boards. Proposed items for inclusion were: a) adding DMA thermal analysis testing for measurement of Tg; b) inserting the property of fracture toughness of laminate resin as an optional test and c) specification sheet rationalization (consolidation) to make the specification easier to use.

The 3-11g Corrosion of Metal Finishes Task Group established the major control parameters for test vehicles, chamber conditions and enough testers for running the mixed flowing gas (MFG) round robin test program, a replication of the earlier creep corrosion testing run by Alcatel Lucent.

The 3-12a Metallic Foil Task Group reviewed test results from eight different test facilities that used either laser or optical comparators for measuring surface roughness on six different samples of copper foil (measured both surfaces of the foil samples). While these samples were not statistically correlated for the various pieces of non-contact measuring equipment, there were definitely some interesting results; enough to continue with the round robin test program.

The 3-12d Woven Glass Reinforcement Task Group discussed next steps on IPC-4412, Specification for Finished Fabric Woven from ”E” Glass for Printed Boards. The group decided to pursue a full revision B of IPC-4412 which now currently contains three amendments.

Fabrication Processes

The 4-14 Plating Processes Subcommittee successfully completed the Ballot for Amendment 1 to IPC-4554, Specification for Immersion Tin Plating for Printed Circuit Boards just prior to the Midwest event meetings. Amendment 1 is currently available for free download on IPC’s website. The group also continued work on IPC-4556, Specification for Electroless Nickel/Electroless Palladium/Immersion Gold Plating for Printed Circuit Boards.

Flexible Circuits

The D-11 Flexible Circuits Design Subcommittee reviewed comments to the Final Draft circulation of IPC-2223C, Sectional Design Standard for Flexible Printed Boards. The document was sent to the subcommittee for ballot approval in October.

The D-12 Flexible Circuits Performance Subcommittee continued work on Revision C to IPC-6013, Qualification and Performance Specification for Flexible Printed Boards. The subcommittee is one of three actively working to update its respective specification with current HDI/microvia industry requirements as part of an overall effort to replace the outdated IPC-6016 specification for HDI/microvias. The subcommittee updated requirements for microvia contact areas and addressed minimum external conductor thickness requirements for various types of flexible printed boards.

The D-13 Flexible Circuits Base Materials Subcommittee successfully balloted IPC-4204A, Flexible Metal-Clad Dielectrics for Use in Fabrication of Flexible Printed Circuitry. The subcommittee also worked to advance IPC-4203, Adhesive Coated Dielectric Films for Use as Cover Sheets for Flexible Printed Circuitry and Flexible Adhesive Bonding Films to its A revision, and completed Draft 12.

The D-15 Flexible Circuits Test Methods Subcommittee advanced the test method, TM 2.1.13, Inspection for Inclusions and Voids in Flexible Printed Wiring Materials to its B revision. The group agreed that the test method should only address identification of voids or bubbles.

Rigid Printed Boards

The D-31b IPC-2221/2222 Task Group prepared a Final Draft for Industry Review of Revision B of IPC-2221, Generic Standard on Printed Board Design, by updating section 12.4 on test coupon design, in conjunction with the work accomplished by the 1-10c Test Coupon and Artwork Generation Task Group. New illustrations were created to provide examples of the location of 1-10c and legacy IPC-2221 test coupons on printed board panels.

Members of the D-33a Rigid Printed Board Performance Specifications and 7-31a Task Groups continued efforts for Revision D to IPC-6012, Qualification and Performance Specification for Rigid Printed Boards. The task group worked on allowances for reduction of the microvia contact area due to processing residues. The task group also discussed the shortcomings of the current internal and external conductor thickness tables, which do not address sequentially laminated layers used for blind and buried vias. A new table addressing internal, plated layers will be drafted for review.

The D-35 Board Storage and Handling Subcommittee discussed goals for revising IPC-1601, Printed Board Handling and Storage Guidelines. It was noted how OEMS often have different storage requirements for printed boards, and how often printed board manufacturers would have rooms of entirely different packaging materials based on what one OEM may specify over the other While the subcommittee encountered difficulty in establishing moisture sensitivity level classifications for printed boards themselves in IPC-1601, it may be possible to establish a small number of packaging levels that might alleviate the variation seen in OEM packaging requirements.

Embedded Devices

The D-55 Embedded Devices Process Implementation Subcommittee continued development of the draft of IPC-7092, Design and Assembly Process Implementation for Embedded Components. The attendees reaffirmed the methodology attempts to simplify the number of different processes that could be used in building an embedded substrate package. These concepts will simplify the methodology that can be built into the document to describe the processing steps needed to build an embedded device product.

Many thanks to all of the volunteers who make IPC standards possible. For more information on IPC standards, visit www.ipc.org/standards.

2 Comments

  1. Maris Graube
    Posted November 14, 2011 at 6:37 pm | Permalink

    Are there any standards for HASL board finish?

    • Kim Sterling
      Posted November 22, 2011 at 8:33 am | Permalink

      Per John Perry, IPC technical project manager, “Our HASL board coverage requirements are basic: “Coverage and Solderable” – we don’t specify a minimum HASL finish thickness. This and other requirements for HASL are in IPC-6012C.”


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