How to Set Arbitrary Backdrill Depth in HFSS 3D Layout
Hello everyone, this is Adel Ben-Elmi from Ozen Engineering, Inc. In this video, I will be discussing the new backtrailing feature in the latest release of ANSYS HFSS 3D Layout 23R1.
Introduction to Backtrailing
Backtrailing is a technique used to remove excess Vs tabs in high-speed digital circuits, which can cause signal reflections and degrade the performance of the circuit.
Demonstration
Previous Version: HFSS 22R2
Let's start by examining an example in the previous version of HFSS, the 22R2:
- We have a simple differential via.
- By clicking on this via and opening the pad stack usage and definition, in the backtrail section, you can see that we can only set the backtrail by specific layer.
- To control the depth or length of the backtrail, a workaround is to create dummy layers.
New Release: HFSS 23R1
Now, let's go back to the new release, the 23R1, where we have more flexibility in setting the backtrail:
- Select the Vs for which you want to set the backtrail.
- Go to the pad stack usage and definition, and open the window.
- In the backtrail section, you can start from the top or the bottom. For this example, let's start from the bottom.
- Define the drill diameter. You can set the backtrail by depth, by layer with an offset, or by a specific layer.
- Specify the drill diameter to 600 micrometers, set it by depth, and use a project variable already defined as "depth".
Click "OK" to apply the settings. It's pretty straightforward!
Conclusion
In this video, we saw how to set the back drill in the latest release. Note that the back drill may affect the impedance and signal integrity of your circuit, so it's important to analyze the results and perform simulations to ensure that the performance is not adversely affected.
Thanks for watching, and see you in the next video!
Hello everyone, this is Adel Ben-Elmi from Ozen Engineering.
In this video, I will be discussing the new backdrilling feature in the latest release of ANSYS HFSS 3D Layout 23R 1. Backdrilling is a technique used to remove excess vias in high-speed digital circuits, which can cause signal reflections and degrade the performance of the circuit.
Before I demonstrate how the backdrill can be configured in the new release, let's start by examining this example in the previous version of HFSS, the 22R 2. Here we have a simple differential via.
If I go and click on this via here and open the pad stack usage and definition, in the backdrill section, you can see that we can only set the backdrill by specific layer. And to control the depth or length of the backdrill, a workaround is to create dummy layers.
Now let's go back to the new release, the 23R1, where we have more flexibility in setting the backdrill. And here, let's say that I want to set the backdrill for the signal Vs. So the first thing to do is to select the Vs, then I'll go to the pad stack usage and definition, and open the window.
Here in the backdrill section, we can start from the top or the bottom. Let's say I want to start from the bottom, so I'll select it here. Now, if I click here, I can define the drill diameter and, as you can see, we can set the backdrill by depth, by layer with an offset, or by a specific layer.
So let's say here I want to specify the drill diameter to 600 micrometers, to be by depth, and here I'll use a project variable that I already defined, which is "depth." I'll say OK and click OK. That's it; it's pretty straightforward.
In this video, we saw how to set the backdrill in the latest release. Note that the backdrill may affect the impedance and signal integrity of your circuit, so it's important to analyze the results and perform simulations to ensure that the performance is not adversely affected.
Thanks for watching, and see you in the next video.
