IPC Standards Progress Reports – Boards, Embedded, Flex and More

2010 IPC Electronics Midwest Standards Development Committees Progress Reports

Following are brief summaries of select committees, subcommittees and task groups.

BASE MATERIALS

The 3-11 Laminate/Prepreg Materials Subcommittee continued its work on Amendment 1 to IPC-4101C, Specification for Base Materials for Rigid and Mulitlayer Printed Boards. This meeting covered: 1) the inclusion of DMA testing for Tg measurement along with DSC and TMA testing; 2) rationalization (consolidation) of specification sheets; 3) continued support of using another optional metric for laminate/prepreg resin, termed fracture toughness; 4) agreement to include a new polyimide specification sheet into Amendment 1 for IPC-4101C; and 5) the potential UL reclassification of numerous FR-4 systems, including removing the segregation of filled and unfilled laminate and prepreg systems.

The 3-11f UL/CSA Task Group met jointly with the D-12a UL 796F/ UL 746F Task Group as a large number of topics addressed involve both “rigid” and “flexible” materials. As UL standards, UL 746E, UL 796C, UL 746F and UL 796F were recently and successfully voted upon by the UL Standards Technical Panel, the discussions centered on the expected topics for future STP meetings.

The 3-11g Corrosion of Metal Finishes Task Group reviewed the proposed creep corrosion test plan using mixed flowing gas (MFG) to accelerate corrosion formation with what turned out to be new members of the 3-11g Task Group. Also, new members were asked if their company or a company with which they were familiar, would possibly be able to participate as a tester on the MFG method.

The 3-12a Metallic Foil Task Group discussed the statistical results of non-contact copper foil surface roughness measurements. Further testing and analysis will take place to pursue the appropriate method for correctly measuring true copper foil roughness.

The 3-12d Woven Glass Reinforcement Task Group addressed the 1 GHz permittivity data submitted from three E-glass yarn manufacturers. It was requested that additional glass manufacturers submit the requested data for better statistical results. Amendment 3 to IPC-4412A, Specification for Finished Fabric Woven from “E” Glass for Printed Boards was approved just prior to the September meeting that resulted in the inclusion of six new E-glass weave styles. Finally, the group discussed hollow filaments/filament voids occurrences and decided that the concept needs to be pursued by E-glass yarn manufacturers.

The 3-12e Base Materials Roundtable Task Group was presented with information that a printed board fabricator had collected what they termed “treater trash.” Specifically, carbonaceous materials that accumulate within a vertical prepreg treater come loose and contaminate the prepreg, reducing the resulting laminate material’s insulation resistance to a lower value, making the printed boards non-usable for larger form factor “mother boards.” OEMs are becoming much more aware of this problem.

FABRICATION PROCESSES

The 4-14 Plating Processes Subcommittee discussed the results of the round robin test program within IPC-4556 covering ENEPIG (electroless nickel/electroless palladium/immersion gold) surface finish. Also, the group confirmed that IPC-4555 on OSP will be released as a white paper.

ENVIRONMENT, HEALTH AND SAFETY (EHS)

The 4-33 Halogen-Free Materials Subcommittee reviewed the A revision of IPC-WP/TR-584, IPC White Paper and Technical Report on Halogen-Free Materials Used for Printed Circuit Boards and Assemblies. There has been some confusing activity within the EU community, where the use of TBBPA flame retardant is being questioned again within some regulating agencies, even though the EU recently gave an OK for its use, based on both human exposure and environmental aspects.

The 4-33a Low-Halogen Guideline Task Group discussed a recently revised working draft for IPC-4903, Guideline for Defining “Low-Halogen” Electronic Products. The guideline includes two different levels of low-halogen electronics. The first level defines low-halogen thresholds based only on the bromine and chlorine in BFR, CFR, and PVC compounds. The second level establishes thresholds for all bromine and chlorine in the products. Additional revisions are being made to the draft guideline prior to circulation for comment.

The 4-34b Marking, Symbols and Labels for Identification of Assemblies, Components and Devices Task Group met to provide a forum for comments on the recently published A revision of J-STD-609, IPC/JEDEC Marking and Labeling of Components, PCBs and PCBAs to Identify Lead (Pb), Lead-Free (Pb-Free) and Other Attributes. The committee agreed to publish a few minor editorial corrections as errata. No other comments or suggestions for change were made.

FLEXIBLE CIRCUITS

The D-11 Flexible Circuits Design Subcommittee continued development of a tutorial appendix to IPC-2223, Sectional Design Standard for Flexible Printed Boards. The goal of the tutorial is to provide guidance to the printed board designer, so that the main body of IPC-2223 contains only design requirements, making it much more readable and useable. This tutorial will be part of the forthcoming C Revision to IPC-2223.

The D-12 Flexible Circuits Performance Specifications Subcommittee continued drafting new microvia and HDI requirements for flexible printed boards as part of an update to the  IPC-6010 Board Qualification and Performance series and the planned cancellation of the outdated IPC-6016 HDI standard. The subcommittee also generated updates to the tables for minimum plating thickness in holes, addressing concerns with thickness of Type 3 and Type 4 flexible printed boards with less than six layers. The subcommittee also updated wording in section 3.4.2 relative to external annular ring requirements, and section 3.4.3 for bow and twist of flexible printed boards and pallet arrays.

The D-12a UL 796F and UL 746F Flexible Circuits Task Group met jointly with the 3-11f UL/CSA UL 796 and UL 746E Rigid Circuits Task Group. (See previous description under 3-11f Task Group).

The D-13 Flexible Circuits Base Materials Subcommittee continued its work on revision A of IPC-4204, Flexible Metal-Clad Dielectrics for Use in Fabrication of Flexible Printed Circuitry.

The D-15 Flexible Circuits Test Methods Subcommittee continued its work on revision B of Test Method 2.6.21, Service Temperature of Flexible Printed Circuitry. Revision B of the document includes testing of adhesive coated dielectric film that will be used as both cover material and bonding sheet material. The B revision is very close to its Final Draft which would then be submitted to the 7-11 Test Methods Subcommittee for insertion into TM-650.

RIGID PRINTED BOARDS

The D-31b IPC-2221/2222 Task Group worked on the preparation of a Final Draft to IPC-2221B, Generic Standard on Printed Board Design, including the drafting of guidance on mitigating conductive anodic filament (CAF) growth. The task group also completed drafting of section 4.4 which addresses a number of alternative printed board surface finishes, based on feedback from the IPC 4-14 Plating Subcommittee. A monthly teleconference scheduled will be implemented so that a Final Draft to IPC-2221B can be completed in time for IPC APEX-Expo 2011.

Members of the D-33a and 7-31a task groups began revision efforts for IPC-6012C, Qualification and Performance Specification for Rigid Printed Boards, and IPC-A-600H, Acceptability of Printed Boards. The task groups addressed the issue of “eyebrow” cracks in double blind via constructions, and came away with a proposed rebuild of the “thermal zone” where certain laminate imperfections are excluded from the acceptance criteria in the standards. The task group also updated acceptance criteria for bubbles in solder mask on printed boards.

The D-35 Printed Board Storage and Handling Subcommittee celebrated the release of IPC-1601, Printed Board Handling and Storage Guidelines. The subcommittee agreed to conduct a poll of document users up through March 2011 to determine categories of interest for a future revision.

EMBEDDED DEVICES

The D-51 Embedded Devices Design Subcommittee met with members of the new IPC D-55 Design and Assembly Implementation Subcommittee, which is initiating the IPC-7092 standard for embedded device printed boards. The subcommittee discussed the transfer of relevant design guidance from the existing IPC-2316 design guide to the IPC-7092 document. This would enable the subcommittee to cancel IPC-2316 and continue the development of IPC-2227, Sectional Design Standard for Printed Boards Containing Embedded Devices, a design requirements standard.

The D-52 Embedded Component Materials Subcommittee considered the second edition (2009) of the JPCA document, EB01, that addresses reliability, design and terminology of embedded devices, both passive as well as active formats. The D-52 also was made aware of a new D-55 Embedded Devices Subcommittee that will consider the applications of both passive and active devices that will incorporate materials information from the D-52 Subcommittee in the applications coverage. It was decided that for the next APEX-EXPO 2011, the D-52 Subcommittee will not meet, as there is not enough new work needed in the materials area.

The D-54 Embedded Devices Test Methods Subcommittee discussed the latest draft of a test method on power density rating (PDR) for embedded resistors. The major disagreements within the subcommittee were resolved, such that a final draft of the TM 2.5.34 will be put together, provided to the full D-54 Subcommittee for any further comments and then submitted to the 7-11 Test Methods Subcommittee for final approval and insertion into the TM-650 Manual.

INTELLECTUAL PROPERTY

The E-20 Intellectual Property Standard Committee discussed comments on the recent ballot of IPC-1071, Best Industry Practices for Intellectual Property Protection in Printed Board Manufacturing. The proposed standard received unanimous approval during the balloting. In order to address some of the comments, some minor changes will be made to the proposed standard and the standard will be reballoted. Publication is expected by the end of 2010.

ROADMAP

The 8-40 Roadmap Executive Committee reviewed actions that took place at IPC headquarters immediately prior to Electronics Midwest. The group confirmed the Roadmap structure, layout characteristics, and assignment suggestions documented in the material circulated to the attendees. A detailed schedule was set which included a teleconference every two weeks up to the December meeting. Drafts of the various sections of the 2011 Roadmap are due by December 15.

JNAC

The Jisso North America Council (JNAC) discussed the results of the meetings in Kyoto, Japan, to plan activities for the United States hosting JIC 12. A major change was recommended in the technical group structure which would combine certain subjects and have a better focus on the activities of each group that relate to the total packaging solution. The concepts derived during the meeting were conveyed to the Executive committee of the Jisso International Council (JIC) and were tentatively accepted for the upcoming meeting in May 2011.

More reports are available at https://blog.ipc.org/2010/11/19/more-updates-from-ipc-committee-work-at-ipc-midwest/ and https://blog.ipc.org/2010/11/03/updates-from-ipc-design-data-transfer-and-documentation-committees/. Visit www.ipcapexexpo.org/standards for upcoming standards development meetings.

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