How to calculate the thickness of layers in a 4-layered PCB?

hi, can anyone help me? I want to make a board design of four layers
top, inner layer 1, inner layer 2, and bottom
the fact is that I want it to be 1.6mm total thickness and use 1oz of copper each layer, but the problem is that I do not know how to calculate the thickness (neither the dielectric) of each layer. I'm working with PADS, and it requires some more parameters. Maybe someone could help me

Re: layer stackup

There is not a simple answer to your question.

It depends on what material you wish to use for your board, which to some extent is determined by what your maximum frequency will be.

It also depends on whether or not you intend to control impedance on any layer, or for any specific net. The impedance of a trace depends on the dielectric constant of the board material, the width of the trace, the thickness of the trace (1oz in your case), the cross-sectional shape of your trace, and the distance between the trace and the nearest return path for the signal on that trace. Frequently, the return path is on an adjacent layer.

There are basically three types of material structures used in fabricating a board. One is "core" which is a cured base material with copper already laminated on one or both sides. The second "prepreg" which is uncured base material used as a dielectric and bonding layer. The third is copper foil which is bonded to prepreg under heat and pressure. "Core" and "prepreg" come in standard thicknesses which depend on the type of material and the manufacturer. Only the fab that is going to make your board can tell you what standard materials and thicknesses are available to them. They can also tell you what the dielectric constant is for the materials they might use.

Having said the above - a representative stackup for a 1.6mm finished board might be:

35um Foil (1oz copper)
2 x .175mm, 7628 Prepreg
.71mm Core with 35um copper top and bottom (1oz copper)
2 x .175mm, 7628 Prepreg
35um Foil (1oz copper)

The laminating process compresses the prepreg to give the proper final overall thickness.

Another way to represent the above would be:

1oz copper
.35mm Prepreg
1oz copper
.71mm Core
1oz coppper
.35mm Prepreg
1oz copper

The best thing to do would be to talk with your local fab, and see what material they will be using.

Re: layer stackup

I personally don’t worry about those the parameters.
Let your board house do the build and specify any requirements you might have like controlled impedance.
I used to specify everything but found that all board houses use different material suppliers and prefer to do things slightly differently.