Altium route to plane

Question

in the past I always used internal Signal layers, on which I created huge GND polygon planes as a ground plane. However, there are actual solid planes definable in Altiums Layer Stackup Manager, which can be assigned a dedicated net. So I assume, the proper way to define a ground plane is to define a plane in the Layer Stack Manager and assign the GND net.

Lets take the following exemplary scenario:

1. Top Layer has some components
2. You define microvias from top layer to inner layer 1
3. Inner layer one is defined in Layer Stack Manager as a solid plane
4. Afterwards assign GND net to inner layer 1
5. You now choose a GND pad of some component on the top layer and try to route it to inner layer 1 using a microvia.

Step 5 cant be performed.

Please let me know, why this is not possible. What am I missing? When should you use planes and when should you use signal layers in Altiums Layer Stackup Manager in order to define your planes?

All the best,

Answer 1

I think planes are only usefull if you want to use impedance calculations and/or automatically impedance controlled traces. Altium can only do that when you route the traces over a plane.

In all other cases I think planes are inferiour to the flexibility of simple polygons on a signal layer. I for my part basically always use signal layers.

Answer 2

I don't think it matters much which one you use- one is defined in negative and one in positive.

For example, if you have several power domains on your power plane you can split the plane rather than using individual polygons. It might be easier to split in some cases rather than creating polygons that are close to each other.

If it's all one net, I don't see much to pick and choose.