IPC Standards Committee Reports – Printed Board Design, Testing, Flex Circuits, High Speed/High Frequency, Rigid Printed Boards

Estimated reading time: 3 minutes

These standards committee reports from IPC’s 2016 Fall Committee Meetings have been compiled to help keep you up to date on IPC standards committee activities. This is the first in a series of reports.

Printed Board Design

The 1-10b Printed Board Thermal Management Task Group met to discuss future testing programs for the evaluation of parallel conductors and flexible circuits towards an update to the IPC-2152, Standard for Determining Current Carrying Capacity in Printed Board Design. The proposed testing seeks participation from IPC member companies in conjunction with college and technical university laboratories.

The 1-10c Test Coupon and Artwork Generation Task Group worked towards future updates to the IPC-2221B Gerber Coupon Generator. The Generator allows for the creation of Gerber files for AB/R and D test coupon designs found in Appendix A of IPC-2221B, Generic Standard on Printed Board Design, for plated hole integrity and registration evaluations. A propagated B/R design was discussed that will address additional via structures such as stacked and staggered.

Testing

The 7-12 Microsection Subcommittee met to resolve negative comments to the Proposed Standard for Ballot copy of IPC-9241, Guidelines for Microsection Preparation (formerly IPC-MS-810). A December 2016 release is anticipated.

Flexible Circuits

The D-11 Flexible Circuits Design Subcommittee met to announce the publication of the new IPC-2223D, Sectional Design Standard for Flexible Printed Boards. Additions to this revision address flexible cross-sectional construction examples and factors that affect impedance and capacitance control for flex and rigid-flex printed board applications.

The D-12 Flexible Circuits Performance Subcommittee met to prepare the Final Draft for Industry Review of IPC-6013D, Qualification and Performance Specification for Flexible Printed Boards. The group addressed issues involving adhesive and strain relief fillets, non-lamination and dielectric protrusion within the rigid-to-flex transition zone.

High Speed/High Frequency

The D-21 High Speed/High Frequency Design Subcommittee reviewed a Working Draft for the future IPC-2228, Sectional Design Standard for High Frequency (RF/Microwave) Printed Boards. The group agreed that any relevant design guidance from the older IPC-2251 and IPC-2252 design guide can be rolled into this document and that those two documents would be cancelled upon the release of IPC-2228. While there is certainly a need to address RF/Microwave design for flexible printed circuits, it was agreed that such content should be addressed with the corresponding IPC-2223 design standard for flexible printed boards and that IPC-2228 will reference that document.

The D-22 High Speed/High Frequency Performance Subcommittee met to announce the release of IPC-6018C, Qualification and Performance Specification for High Frequency (Microwave) Printed Boards and the corresponding IPC-6018CS Space and Military Avionics Applications Addendum. Both documents are targeted for a Q3 2016 release. These revisions provide updated acceptance criteria for microvia structures and PTFE laminates (e.g. smear removal).

The D-24b Bereskin Test Methods Task Group met work on a new IPC-TM-650 Test Method addressing the Bereskin stripline resonator test method that lends itself to the test and measurement of Dk and Df of thin dielectric materials up to 20 GHz.

The D-24c High Frequency Test Methods Task Group meet to review a proposal for a new IPC-TM-650 test method addressing microstrip differential phase length useful for approximating Dk over a wide range of frequencies.

The new D-24d High Frequency Signal Loss Task Group met for the first time to discuss a proposed test method addressing the quality of measured date for printed boards to meet the demands of high speed applications of 25Gbps and above.   The effort will address verification of the accuracy of measured data, calibration and de-embedded techniques, and probing/test fixture choices that impact measurement quality.

Rigid Printed Boards

The D-31b IPC-2221/2222 Task Group met to advance the working draft of IPC-2226A, Sectional Design Standard for HDI Printed Boards, which is the first revision effort for this standard since its original 2003 publication. The group focused on sections and graphics for various structures, included stacked, staggered and variable depth microvias. A Final Draft for Industry Review is planned for release for review and comment by December 2016.

The D-33a Rigid Printed Board Performance Task Group and the 7-31a IPC-A-600 Task Group met jointly to work on a future Revision E to IPC-6012, Qualification and Performance Specification for Rigid Printed Boards, including copper wrap plating, evaluations for surface finishes in production lot testing, back drilling and via fill “plate-to-plate”, often referred to as “double capping”.

The D-32 Thermal Stress Test Methods Subcommittee met to work on revisions to IPC-TM-650 Methods 2.6.7.2, Thermal Shock and 2.6.27, Thermal Stress. The test methods are being updated to address in process electrical resistance measurements of samples during thermal cycling.   A significant set of data correlating the electrical resistance measurements to failures occurring during thermal cycling was provided by Jerry Magera of Motorola Solutions.