IPC Standards Committee Reports: Base Materials, Fabrication, High Speed/High Frequency, Embedded Devices

pictureThese standards committee reports from IPC APEX EXPO 2014 have been compiled to help keep you up to date on IPC standards committee activities. This is the second in a series of reports.

Base Materials

The 3-11 Laminate/Prepreg Materials Subcommittee successfully revised and balloted IPC-4101D, Specification for Base Materials for Rigid and Multilayer Printed Boards. An ad hoc working group completed a draft of the IPC/CPCA-4105 standard on laminate material for primary use as a substrate for LED lighting applications. The subcommittee has planned work on an amendment to or next revision of IPC-4101D to include improved laminate cleanliness as desired by the European Space Agency.

The 3-11f UL/CSA Task Group discussed rigid and multilayer materials and printed boards. The group examined the Relative Thermal Index (RTI) for 50,000 hours (5.7 years) vs. the current 100,000 hour rating as tested by UL. OEMs are now pushing for the shorter rating, especially for consumer electronics where the expected life span for portable devices is not anywhere close to the near 6 years (50,000 hours) RTI. If approved, UL would maintain a dual listing for materials. In addition, the task group discussed shortening the current 5,000 hours long term thermal aging (LTTA) to potentially 2,000 hours to shorten the 746E qualification time for new laminate materials.

The 3-11g Corrosion of Metal Finishes Task Group discussed metal finish corrosion on component leads and printed board surface finishes. The Flowers of Sulfur (FoS) corrosion test method for surface mounted chip resistors is nearing completion. The task group heard presentations by Drs. Bhanu Sood and Michael Osterman of University of Maryland’s Center for Advanced Life Cycle Engineering (CALCE) comparing results between corrosion testing using Mixed Flowing Gases (MFG) with FoS Dr. P. J. Singh of IBM on iNEMI’s work with creep corrosion analysis using FoS testing.

The 3-12a Metallic Foil Task Group addressed the non-contact surface roughness test (proposed TM 2.2.22). As an off-shoot of that work, Dr. Arvind Partha of Olin Corp. performed some roughness measurements with some unexpected results. While the task group has been holding frequent teleconferences to complete TM 2.2.22, the group has been stalled over the topic of filters, as to type or use at all for measurements. At the meeting, the group decided to conduct round robin testing of roughness measurements.

The 3-12d Woven Glass Reinforcement Task Group completed the ballot process on Amendment 1 to IPC-4412B, Specification for Finished Fabric Woven from “E” Glass for Printed Boards. The task group is also pursuing a possible test method for measuring weave size for “spread glass.”

Fabrication Processes

The 4-14 Plating Processes Subcommittee reviewed revision efforts underway on IPC-4552, Specification for Electroless Nickel/Immersion Gold (ENIG) Plating for Printed Circuit Boards, primarily for those meeting attendees who have not participated in regular teleconferences. The group also reviewed work that has occurred on test methods designed to measure the phosphorus content of electroless nickel plating and the stripping of overplated immersion gold. In addition, the subcommittee members worked on defining acceptable hyper-corrosion of nickel underplate.

High Speed/High Frequency

The D-22 High Speed/High Frequency Performance Subcommittee reviewed and approved requirements for the material fill of blind, buried and microvia structures in the working draft of IPC-6018C, Qualification and Performance Specification for High Frequency (Microwave) Printed Boards. The group also reviewed industry feedback from a survey demonstrating the need for an IPC-2220 series design standard for RF/Microwave printed boards. Currently, only design guides exist and thus the technology section is lacking in specific design requirements. A scope for the planned IPC-2228 will be drafted for review at the September 2014 meeting.

The D-23 High Speed/High Frequency Base Materials Subcommittee balloted and approved Amendment 1 to IPC-4103A, Specification for Base Materials for High Speed/High Frequency Applications.

Embedded Devices

The D-55 Embedded Devices Process Implementation Subcommittee discussed IPC-7092, Design and Assembly Process Implementation for Embedded Components, which describes the design and assembly challenges for implementing passive and active components in either formed or placed methodology inside a printed board. The subcommittee reviewed comments from industry circulation and agreed on the disposition of comments. The next stage is the incorporation of the changes and circulating the draft for ballot.

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