Gauss Stack – Microvia Reliability
With the advent of higher layer count HDI applications, the use of Microvias has greatly expanded – as more and more builds are 3+N+3 or even more sequential laminations, the use of skip vias, staggered, and stacked microvias is becoming essential. The major problem, though, is that Microvias seem to be far more likely to fail than Plated Through Holes. Simply put, smaller holes that don’t go all the way through are going to be subject to more stress, and, as a result, be more likely to fail during Reflow, Accelerated Testing, or in Service Conditions.
The Challenge with Microvias
Because of their small size, microvias are even more susceptible to failure than Plated Through Holes are. This makes it very difficult to design boards with microvias that are able to survive reflow and the intended service life of your product. The solution is typically to build test vehicle boards and subject these batches to Accelerated Testing, using test approaches that allow you to observe failure in your boards – but this solution doesn’t provide any guidance as to what changes you need to make to your design to eliminate the problem.
The Solution: Simulation of Microvia Reliability
Because building test vehicle boards only allows you to verify if your design is okay or not, the only option there is of trial-and-error. This process can become incredibly expensive and, especially if you are working with a particularly challenging design, such as one with stacked microvias, this process may take a very long time before bearing fruit, or may just lead to abandonment of a particular feature. A rapid simulation environment, where you can observe the impact of changes to parameters related to your microvias or to your stackup, would be an incredible boon for this development process, as it would allow you to design against testing failures or field failures – in days, not months. That is precisely what Gauss Stack’s Microvia Reliability simulation enables you to do.
Microvia Reliability Simulation in Gauss Stack
Just like with Plated Through Hole reliability, Gauss Stack allows you to simulate Microvia Reliability for Reflow, Accelerated Testing, and Service Conditions, with just a few clicks – simply specify the top and bottom layers of the via, along with the subjected thermal cycles and the diameter, pitch, and plating (if not filled) of the vias and Gauss Stack will, in seconds, provide you with median cycles to failure or, if reflecting service conditions, median life to failure in terms of years of expected operating life, along with Stress and Strain curves, just as with the Plated Through Holes. To accomplish this, Gauss Stack conducts a thermomechanical simulation specifically for the module or subassembly consisting of the layers starting at the top of your specified via and ending at the bottom of your specified via, followed by the relevant simulation of the via, subjected to the specified thermal conditions, so you can Computationally Prototype your boards for Microvia Reliability without ever having to build a test vehicle board!
Predict Microvia Reliability with Gauss Stack Today!