Microvia

Driven by portability and wireless communications, the electronics industry strives to produce affordable, light, and reliable products with increased functionality.

The HDI layers are usually built up from a traditionally manufactured double-sided core board or multilayer PCB.

Ogunjimi et al.[9] looked at the effect of manufacturing and design process variables on the fatigue life of microvias, including trace (conductor) thickness, layer or layers of the dielectric around the trace and in the microvia, via geometry, via wall angle, ductility coefficient of the conductor material, and strain concentration factor.

Finite element models were created with different geometries, and ANOVA method was used to determine the significance of the different process variables.

Prabhu et al.[10] conducted a finite element analysis (FEA) on an HDI microvia structure to determine the effect of accelerated temperature cycling and thermal shock.

Andrews et al.[13] investigated single-level microvia reliability using IST (interconnect stress test), and considered the effect of reflow cycles of lead-free solder.

[16] The authors of [16] have been investigating the risk of microvias in terms of voids and other defects using both experimental testing and finite element analysis.