Issue link: https://iconnect007.uberflip.com/i/1284035
118 SMT007 MAGAZINE I SEPTEMBER 2020 interface that was guilty all the time. The one on the left shows the interface between the electrode copper, and the landing pad within the electroless copper deposit is in the center; on the right is between the electroless copper and the fill. It does not necessarily occur on one stack. Although, you will see that there is currently more stress found in the deepest microvia. The product characteristics are intermittent. They open more at hot temperature versus cold temperatures, and this self-healing effect is a real problem in intermittency. The failures occurred after the finished product was stored for weeks or months; it passed test at the time of fabrication and initial assembly but dropped out after storage. A failure after field deploy- ment is the costliest of all failures. This is an unpredictable reliability issue that needs to be resolved. Table 1 shows the structure of the IPC Weak Microvia Failure Committee Sub-Teams, includ- ing simulation and modeling. The two groups (1b and 1d) are in yellow, as we are melding the characterization and test methods team with the construction design elements team. There is a laminate sub-team, a chemical pro- cesses and metallurgy team, and the whole for- mation team, which were highly active. A year ago, after formation and trying to collect field data (which was not forthcoming), this com- mittee was inactive. It will reactivate after IPC test data from the test program that we outline is disseminated. You might ask, "What can cause weak microvias?" Figure 5 shows a fishbone diagram Table 1: IPC Weak Microvia Failure Committee Sub-Teams. Figure 5: Various factors in the understanding of weak interfacial bonds for microvias.