Gauss PCB Stackup Design & Simulation (Gauss Stack)

Along with Avishtech's leading edge Gauss 2D Electromagnetic Transmission Line Field Solver, the Gauss PCB Stackup Design & Simulation tool can be used to develop sophisticated printed circuit board stackup configurations for aid in the development and manufacture of printed circuit board designs of virtually limitless size and variety. A streamlined, straightforward to use, clean-interfaced solution to an ongoing concern in the industry, Gauss Stack offers users the ability to easily develop PCB stackup designs for use in manufacture or prototyping. By using the in-built Gauss 2D engine, users can build stackup designs quickly without significant trial-and-error using impedance analysis to calculate trace impedances or synthesis mode to find trace widths for given target impedeances.

Avishtech's feature-rich offering also acts as the front-end input for a series of highly advanced research & development and design simulation software beyond anything else in the market: allowing for advanced design for reliability virtual testing, warpage simulation, and, dimensional stability simulation, the last two of which are both industry first solutions to ongoing major problems in development and manufacture of PCBs and packaging solutions!

The Design for Reliability capability allows users to get automated checks for validating several aspects of the practicability, manufacturability, and reliability of their designs. Gauss does the math for you to make sure that your designs have enough resin content to fill voids, that all features are dimensionally sufficient to sustain the particular choices of grades of glass and copper, that retained copper percentages and layers are within reason, among other checks, all of which adds up to higher reliability of board designs and a more robust manufacturing process.

The Warpage Simulation capability allows users to perform a simulation on the complete stackup to determine the warpage behavior under stress by simulating the cylic conditions to which the board will be subjected during processing and use. Warpage, especially in packaging applications, is a major cause of waste and scrap. Validation of choice of materials and stackup can prevent much of the headache, and lost time, money, and effort currently devoted to reruns and rework in the manufacturing process.

The Dimensional Stability simulation capability offers something never seen before in the industry: the ability to predict dimensional stability problems in printed circuit boards, during the design stage, without needing to run a long series of scout batches, which lead to massive waste and expensive material scrap. This industry-first solution allows a user to bypass this by allowing for "Virtual Scout Batches" as a replacement for physical scout batches, saving immense amounts of time and money, while also improving the final board design, thereby improving performance.

Gauss Stack's simulation and design capabilities allow users to solve some of the most challenging and expensive problems in PCB manufacture!

Design for Reliability
In the typical design process, insufficient resin content can lead to glass stop, where the glass comes into contact with copper, with no resin to act as the interface.
Glass Stop
The built-in Design for Reliability tool will prevent glass stop (by ensuring a sufficient resin-filled gap), as well as several other problems, by conducting key design rule checks.
No Glass Stop
Warpage Simulation
In the typical design process, you cannot predict warpage behavior, and, thus, you can produce several failed batches of heavily warped material (as shown below)
Warped Stackup
With the Warpage Simulation tool, you can accurately predict this behavior, so that you can build a normal stackup with less trial and error!
Normal Stackup
Dimensional Stability Simulation
The traditional design process suffers from scout batches with dimensional stability problems. The diagram below shows the unrestrained (transparent) vs real size.
Dimensionally Unstable Stackup
With the Dimensional Stability simulation tool, you can predict dimensional changes to your stackup, allowing you to compensate, accordingly, by knowing where every feature is!
Dimensionally Stable Stackup

The Design for Reliability tool allows users to conduct automated design rule checks to prevent numerous problems that arise from incompatible selections of materials or dimensions. Using the warpage and dimensional stability simulation tools, you can predict dimensional stability and warpage behavior virtually. This allows you to bypass the traditional trial-and-error design process, which leads to significant waste in terms of time, money, and other resources. Avishtech's offerings allow for a streamlined design process, that results in significant cost-savings and improved performance of designs.

Key Features of Gauss PCB Stackup Design and Simulation Tool

With Avishtech's Gauss Stack, you not only get an extremely easy-to-use and visually elegant stackup design tool, but also the industry's only complete simulation environment for PCB stackups. The software is extremely rich and features:

  • Electromagnetic Simulation: Gauss Stack contains within it the full functionality of Gauss 2D (our 2D Field Solver), which enables full electromagnetic simulation of the stackup layers you have designed in Gauss Stack, to help design for impedance.

  • Design for Reliability Checks: our PCB stackup tool goes the extra mile, by helping you design stackups that are manufacturable and reliable. Gauss Stack checks to make sure that your designs have sufficient resin, appropriate properties, and more, to avoid problems before the prototype or manufacture stage.

  • Glass Stop: unlike other PCB stackup design tools, Gauss Stack helps you avoid major problems like glass stop. Glass stop is when there is not enough resin for a particular retained copper percentage to fill the gaps in the copper upon pressing. This results in regions of your PCB having exposed ends of glass fiber bundles, without any resin surrounding them, leading to reliability issues and reduced board life. Gauss Stack checks your stackup for compatibility between your resin contents and retained copper percentages and points out any suspect layers that may be likely to result in glass stop.

  • Dimensional Stability Simulation: our most exciting and groundbreaking feature, Gauss Stack goes where no other PCB stackup tool, or any software in the industry, for that matter, can, by enabling highly accurate and fast dimensional stability simulation. This allows you to take a PCB stackup design and determine relative expansion and contraction of each layer relative to each other, allowing you either to revise your design to build more dimensionally stable stackups or to compensate for the predicted deviations when laying out the board during manufacture, leading to immense cost-savings for PCB board shops (by eliminating waste from scout batches) and to overall better performance of board designs. 

  • Warpage Simulation: warpage simulation goes hand-in-hand with dimensional stability simulation. While calculating for in-plane deviations, the direct measure of dimensional stability, one can also model out-of-plane deviations, which manifest as curvature, or warpage. Gauss Stack thus takes your PCB stackup designs and generates outputs that capture both the anticipated in-plane and anticipated out-of-plane deviations, something you cannot get anywhere else!

  • Multiple Dielectrics Per Layer: Gauss Stack allows you the flexibility to build PCB stackups with multiple dissimilar dielectric materials per prepreg or core layer. Beyond the simple value of capturing this in your stackup for prototyping or manufacture, Gauss Stack also uses this information to more accurately model your stackup, both for electromagnetic simulation (through the internal Gauss 2D engine) and the in-built thermo-mechanical simulations (including dimensional stability and warpage simulations).

  • Build Virtually Any Board: With the flexibility that Gauss Stack provides, you can build virtually any PCB stackup of arbitrary number of layers and size, combination of glass styles, and construction (core/cap or foil), with all of these being accurately simulated both in terms of electromagnetic behavior and in terms of dimensional stability and warpage analysis, all housed in a single, easy-to-use tool.

  • Design Advisor: Gauss Stack acts like an advisor to your development process, providing you with insights into geometric and material constraints on your design that could lead to problems in prototyping and manufacture, ensuring that your stackup is physically possible, something that is not often obvious without carrying out several concurrent calculations.

  • Library of Materials: Gauss Stack features the ability to quickly and easily save materials to a local library for use in future PCB stackup designs, in addition to several key generic materials that are pre-loaded into your library.

  • Pressed Thickness Calculation: unlike some of the more basic PCB stackup tools, Gauss Stack calculates the pressed thickness of your stackup.

  • Easy Export of Data: Gauss Stack allows you to export your PCB stackup design, as well as your simulation outputs (both electromagnetic and dimensional stability/warpage) to Excel or .csv format, for use in your favorite analysis environment.

  • Rapid Construction: in Gauss Stack, with the ability to mirror the construction, apply a set of properties to all layers of a particular type (e.g. "Prepreg"), and apply a set of properties to each copper layer style, you can build an arbitrary PCB stackup in just a few keystrokes and clicks.

  • Mapping Out Vias: Gauss Stack allows you to account for vias in your PCB stackup design by adding this to the pictorial representation of your stackup, to help with routing of lines and traces.

With all these features and this enhanced functionality, packed into an intuitive, easy-to-use, elegant, and modern PCB Stackup Design and Simulation tool, Gauss Stack is the clear choice for your PCB design and simulation needs.

How Does Dimensional Stability and Warpage Simulation Help Me?

Sure, Gauss Stack is the only solution in the market that enables me to run dimensional stability and warpage simulations on my PCB stackups, but what does that really do for me?


To answer this, we start by briefly discussing why inconsistent dimensional deformation and high warpage can be problematic. Simply put, when a multilayer PCB is thermally cycled, each layer expands and contracts differently, due to mismatches between coefficients of thermal expansion (CTEs). As the board is relaxed, this leads to curvature (warpage), as well as in-plane deviations (dimensional deformation, more commonly known as dimensional stability). This presents a problem in accurate routing of transmission lines, vias, and other features on a PCB, because the physical board is no longer in line with the schematics of the design.

Predicting this behavior has been quite challenging and, prior to Gauss Stack, there was no commercially available solution. Thus, PCB board shops largely had to rely on trial and error, with developing scout batches and databases to determine the deviations and either guess at what might make a better design or try to compensate for the deviations in the routing of the board, leading to massive waste and loss, in terms of material, capital, man-hours, and machine productivity, not to mention lost opportunity for quick-turn service.

With Gauss Stack, however, this process has fundamentally changed. Now, you can simply use the built-in dimensional stability and warpage capabilities to either modify your design virtually until it meets appropriate tolerances, or to use your virtual baseline to compensate for deviations in situ, without the need for endless scout batches.

Gauss Stack enables true virtual R&D.

© 2020 by Avishtech, Inc.

Avishtech, Inc.
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