'bump'ing Up Coverage

摘要

Test access continues to be an issue, especially for in-circuit test, which is fundamentally dependent on electrical access. One way to battle the access issue at ICT is through Bead Probe technology. This novel method is steadily becoming more mainstream, and the number of licensees increasing rapidly.rnBead Probes enable us to look at test access in a new way. A Bead Probe, which is a soldered bump (FIGURE 1), can be placed directly onto copper signal traces.rnThe bumps are added using existing solder paste printing principles, reflowed using standard procedures, and then serve as the probe test point for ICT access. Beads are layout-independent (i.e., they can be added after copper layout without the need to move or modify traces) and use standard ICT methods. The bumps also merge the world of the process engineer with the test engineer - a long separate bunch of folks! This month, I explore some of the recent discoveries with using these novel bumps in a manufacturing environment. As with anything new, education, . experimentation and practice will make perfect.