Two Layer Board

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I am designing a two layer board. Both sides i am selecting as a signal layer. how to create a ground plane in the bottom layer of the signal layer. Because i need to ground it

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I found this from the documentation:

Copper layers have a function attribute that is useful when using the external router Freerouter .

This means that selecting signal/power as the layer’s “function” doesn’t actually mean anything for KiCad.

You must draw zones. Layers aren’t filled automatically as planes.

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Draw a zone on the bottom layer and allocate the GND net to it. Make a connection to it with a via or device pin and it will fill as best it can.

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Hi Sir,
I can understood, what u have mentioned but i have a little bit doubt. make a connection to it with via means?? it will enter into the top layer how its possible.

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Another doubt whether I have to create power zone also for this two layer board

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vias are plated through holes that create an electrical connection between different layers (in your case between the top and bottom layer)

For an explanation of plated through holes: https://www.pcbunlimited.com/engineering/plated-non-plated-through-holes

They of course depend on you using a manufacturing process that has plated through holes. (Every modern fab offers this as the default option but home made pcbs most likely do not have this.)

Zones can decrease the effort you must make to get good EMC results. This is because an uninterupted copper plane takes care of least impedance return paths without the designer needing to think about it. The key word here is uninterupted which you will not easily achieve in a two layer board. (You either need to have one side with very few traces for anything else except reference potential or you need to have a plane on both sides and stitch them together using vias to simulate an uninterupted plane. This is an art that will take practice.)

It is very unlikely that you can use zones on a 2 layer board for anything else then your reference potential (Most likely ground)

Another usecase for zones is to reduce the copper free area -> The area that needs to be etched away. Doing so can make pcb production more reliable especially for homemade pcbs. (Having a large area that needs to be etched away combined with many small areas can mean that you will loose some traces when etching in the time needed for the large area to be gone.)

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