[SOLVED] How to configure 4 Layer PCB setting using DRC in Eagle?

[omkolhe]

Hello,
I am making a 4 layered RF Board. I have planned to have the following 4 layers
1. RF Lines
2. GND
15. POWER
16. Digital

All the components are on the Top Layer.

I am trying to use the Layer setting in Design Rules so that I can have vias from (1 to 2), (1 to 15), (1 to 16), (2 to 16) and (15 to 16).
I am unable to achieve this. I tried ((1*2)*(15*16)). But this doesn't allow me to have vias from 1 to 15. Thus i am unable to route my power lines.
Please help me to set these settings. Is there a way that I can route in any layer and go from any layer to any layer.

Thank You,
Regards,
Om Kolhe.

 

[KlausST]

Hi,

A usual 4 layer setup is:

(1+2*3+16).
This means:
You hae one inner core with layers 2 and 3 --> "2*3"
This coe is enclosed by two prepregs --> "+2*3+"
Then you have the outer layer top and bottom --> "1+2*3+15"
Then it tells that all vias go through all layers "(1+2*3+16)"

****
In your case there is no prepreg between the cores. I think this is the problem.
Try this: "((1*2)+(15*16))"
This enables to set buried vias at core1 from layer1 to layer2, and buried vias at core2 from layer15 to layer16.
All other vias go through the complete board, but it should enable you to connect random layers with random layers.

Klaus

 

[omkolhe]

Hi Klaus,
Thanks for your help.
I tried using "((1*2)+(15*16))".
But I still faced problems. I have a Voltage regulator IC on the top layer. Now I want to route the Vout of the voltage regulator from the 15th Layer to an IC pin which is placed on the Top Layer. How can I solve this problem?
I get an error - Can't set via to layer '15' at (-828 600)
Regards,
Om Kolhe

 

[SLK001]

Because of the PCB construction, you won't be able to have a 1-15 via. This via must be a thru via.

 

[omkolhe]

Hey,
Thanks SLK001.
I used a thru via everywhere I needed a 1-15 via.
What is the exact reason that we cannot use a 1-15 via?

Regards,
Om Kolhe.

 

[KlausST]

Hi,

What is the exact reason that we cannot use a 1-15 via?

There are:
* blind vias (from one side)
* buried vias ( through one core)
* through vias ( through the whole board)

Now your setup shows two cores. This means for 1-15 you need to drill one core completely and the prepreg.
And I think the prepreg is the problem, because it is neither fixed to a core nore stable enough to be drilled.

Maybe here is a member that is more in PCB manufactoring process than me...
Or ask your PCB manufacturer for details.

Klaus