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Subject: Re: [Homebrew_PCBs] 4 layer pcbs

From: DJ Delorie <dj@...>
Date: 2007-11-20

"Stefan Trethan" <stefan_trethan@...> writes:
> I don't understand how you can solder the VIAs in between the boards,
> for example.
>
> Maybe you can like sketch a cross section?

I'll try... = is copper, - is some other boundary, # is solder, W is
wire, copper marked with ∗ is drilled before taping layers together:

Through via:
#####W#####
=================== W ====================== signal
| W | 8 mil FR4
==========--======= W =======--============= ground
| W | 16 mil FR4
------------------- W ---------------------- (tape between boards)
| W | 16 mil FR4
==========--======= W =======--============= power
| W | 8 mil FR4
=================== W ====================== signal
#####W#####

Blind via:
###################
=============== ######### ================== ∗
| ######### |
============================================

--------------------------------------------

============================================

============================================


Far-plane via:
#####W#####
=================== W ======================
| W |
==========--======= W =======--=============
| W |
------------------- W ----------------------
| W |
=================== W ======================
| #####W##### |
=========== ============ ∗