PCB thickness
Hi Tenny,
as NIKHILRAJ wrote; you must consult your producer for available thicknesses_ the FR4 producer can deliver in 50um steps, but I think, no PCB producer can & will have all versions on stock...
Its good to see as goal ca at 0.3-0.5mm for both outer basis plates, the rest of your 1.6 mm plate thickness can you select as youlike, bitif you have i.e. high speed electronics on board: its favorable to take for these supply and corporate GND to use a thinst basis plate/material or core(i.e. only 100um with 2x cooper, its will work as a couple of 100pF bypass capacity on the right place for your supply
...
Even 1x cooper/2x cooper or no cooper on the basis plates=all these versions are possible in the PCB fabrication, typically will your vendor 1x/2x cooper + the needed prepregs (in the same 50um steps as basisplates/cores) use, but believe us: A CONSULTATION IN DETAIL IS NEEDED WITH YOUR PCB PRODUCER...
Most PCB producer have a "inhouse" stackup_it will be cheaper for you (if its a passable in sortiment) & in shorter time delivered as some extra construct...
BTW;
Cooper thicknesses can be others as 35um too, than the basis plates (or cores) are with 7.5/17/35/50/100um... cooper to order.
K.