Calendar

Tuesday April 1

10:00-2:00 (see details below) 10:00-11:00 a.m. 11:00 a.m.-noon 12:45-2:00 p.m.	Board and Systems Manufacturing Test TIG — new projects (Room: Islander B) TIG (Technology Integration Group) overview This new TIG was organized in 2007 to address issues relating to board and systems manufacturing test. Board Flexure Standardization Project The motivation for this new initiative is the need to update current board flexure standards to encompass changes relating to lead-free electronics and to encourage industry adoption of the spherical bend test method as well as consistent strain measurement techniques that are more reflective of ICT testing and assembly. These changes will minimize and help manage risk during manufacturing and assembly, and will allow consistent determination of risk exposure, while providing standardized metrics and methods to be followed. The team's work will target IPC/JEDEC-9702 (Monotonic Bend Characterization of Board-Level Interconnects) and IPC/JEDEC-9704 (Printed Wiring Board Strain Gage Test Guideline) Boundary Scan Project This project will promote wider adoption of boundary scan (IEEE 1149.1, 1149.6 and P1581) throughout the industry, encourage semiconductor vendors to include the technology in their products, and promote the development of tools by ATE vendors to support boundary scan based board test. Design-for-test is currently not accepted in the general area of memory devices (SRAM, DRAM, flash, etc.). In addition, tools to support boundary scan based test need to be developed and integrated into manufacturing test equipment. This project proposes to bridge the gap between board test and board manufacturing where this lack of understanding arises in the use of design-for-test.
1:30-3:00 p.m.	Forum F01 — iNEMI Lead-Free Forum This session, which is free for anyone attending the exhibition, will review Phase I results of iNEMI's Pb-Free Wave Soldering Project (presented by project Chair Denis Barbini, Vitronics Soltec) and final results from the recently completed Pb-Free BGAs in SnPb Assemblies Project (presented by project Chair Robert Kinyanjui, Sanmina-SCI). The Pb-Free BGAs in SnPb Assemblies Project was originally organized to assess the process parameters for assembling Pb-free SnAgCu BGAs under the temperature constraints of a conventional tin-lead (SnPb) assembly process. The objective was to understand the reliability of the resulting mixed-alloy solder joints. The first phase of the project characterized the peak temperature effects on Pb-free BGAs in SnPb paste. The second phase studied the reliability of Pb-free BGAs processed within the temperature constraints of SnPb assembly conditions. The team investigated reliability of mixed-alloy solder joints under accelerated thermal cycling (ATC) of 3500 test cycles within a temperature range of -40(C to 125(C. The data from this work, which examined failure modes, will be discussed. (See additional discussion below.) The Pb-Free Wave Soldering Project was organized to investigate use of the iNEMI-recommended Pb-free alloy for wave soldering, characterizing the impact of Pb-free alloys on wave and/or selective soldering processes. Phase I of the project provided insight into the process issues encountered with Pb-free wave soldering so that a rational implementation strategy for a robust lead-free process could be achieved. Phase II of this project is under way. The goal of this phase is to characterize the reliability of through-hole joints on a test vehicle specifically designed to test the norms and practices used in tin-lead wave soldering and develop new standards for lead-free wave soldering. The test boards are being inspected, undergoing accelerated thermal cycling (ATC), and will also be submitted to bend and vibration testing. This session will report on the latest results.
1:30 p.m.	IPC A-610 Telecom Addendum Task Group This IPC standards group is meeting 10:00 am - 5:00 pm on Tuesday, April 1 (chaired by Darrin Dodson, Alcatel-Lucent). This task group is developing an addendum that provides "exception" requirements to IPC-A-610D, "Acceptability of Electronic Assemblies." This addendum will enable users of the standard to specify fabrication and acceptance of electronic assemblies used in the telecom industry. iNEMI will make a presentation on board flexure standardization at this meeting (IPC/JEDEC-9702 and 9704), presented by Rosa Reinosa (Hewlett-Packard), chair of the iNEMI Board & Systems Manufacturing Test TIG and the Board Flexure Standardization Project. The presentation will highlight document revision needs recommended by industry.
2:00-5:00 p.m.	Board Coplanarity in SMT Project (Room: Islander B) This new initiative will develop recommendations for measuring board land coplanarity and will work with IPC to create standards based on these recommendations. Determining coplanarity is critical for ensuring high-quality, high-yield SMT processes for the next generation of BGA components and boards. The current specifications for component lead coplanarity and board bow and twist have not kept pace with developments in packaging and board technology. Some system manufacturers are experiencing poor SMT yields using materials that meet the current specifications. New measurement techniques have enabled the measurement of flatness during simulated SMT conditions, allowing more directly relevant standards to be developed. Several standards bodies have already issued standards for using these techniques in components, and these standards could be extended to ensure the flatness of system boards. This iNEMI project will: • Establish metrologies needed to measure board flatness in land area of components and connectors at both room and elevated temperatures. • Develop strategy for setting requirements for differing board technologies and categories. • Recommend acceptance criteria for board flatness and conditions for sampling and measurement requirements.
3:15-4:45 p.m.	Session S08-Repair and Rework "iNEMI Rework Machine Temperature Tolerance and Repeatability Study," presented by Jasbir Bath, Flextronics International This paper reports on results from the iNEMI Rework Optimization Project's BGA/CSP rework machine repeatability and tolerance temperature study. Little data exists on temperature repeatability of BGA/CSP rework machine equipment. This is especially an issue for Pb-free rework as the temperatures during Pb-free BGA/CSP rework are likely to be higher than reflow soldering, leading to potential component and board temperature related issues. A series of evaluations was conducted on rework equipment from four rework machine equipment suppliers. In Phase 1 of the program each rework machine supplier recorded temperatures using its defined Pb-free profile with a specific rework machine. In Phase 2, each supplier repeated these tests on a different machine of the same model. A comparison was then done to analyze the temperature and time data from Phases 1 and 2 to determine rework machine temperature repeatability and tolerances.

Wednesday, April 2

9:00-10:00 a.m.

Session S15-Backward Compatibility: Where Leaded and Lead Free Collide
"Solder Joint Reliability of Pb-Free SnAgCu Ball Grid Array (BGA) Components in SnPb Assembly Process," presented by Robert Kinyanjui, Sanmina-SCI
This technical session will provide further discussion of the PbFree BGAs in SnPb Assemblies Project. The paper reports on the project team's experimental investigation of the reliability of solder joints of SAC BGA components formed using Sn-Pb solder paste., specifically looking at the impact of package size, solder ball volume, printed circuit board (PCB) surface finish, time above liquidus and peak temperature on reliability. Different BGA package sizes, PCB finishes and profiles were tested, with a total of 60 boards assembled. Analysis of as-assembled solder joints revealed that for a time above liquidus below 90 seconds, the degree of mixing between the BGA SAC ball alloy and the Sn-Pb solder paste was less than 100 percent. Also, depending on package size, the peak reflow temperature was observed to have a significant impact on the solder joint microstructural homogeneity. The influence of reflow process parameters on solder joint reliability was clearly manifested in the Weibull plots. This paper provides a discussion of the impact of various profiles' characteristics on solder joint reliability.

1:00-3:30 p.m.

Halogen-Free Next Steps Meeting (Room: Islander B)
This iNEMI meeting is open to industry and will discuss, evaluate, and prioritize plans for future halogen-free project activities. The current three-phase iNEMI Halogen-Free Project is nearing completion, developing guidelines for standardized materials, manufacturing, assembly and test for "halogen-free" printed wiring boards based on market segment requirements and technical, commercial and functional viability.

In Phase I, the current project team identified market segment requirements, candidate materials, key performance characteristics and test criteria. In Phase II, the group developed test plans, which focus on electrical characteristics, delamination and via reliability. In Phase III they will measure the broadband frequency-dependent dielectric constant and loss tangent of candidate halogen-free laminate materials (10KHz-20GHz). The group will then determine the compatibility of candidate laminate materials with higher-temperature assembly process reflow environments (mixed solder: 245˚C; Pb-free: 260˚C). Throughout this process, the team will consider unique market segment requirements, identify technology readiness and gaps, and stimulate supply capability.