Beagleboard fabrication process.

This question goes to the actual bare board process used to make the 6
layer board. Do you all, probably Gerald maybe others, have any
documentation or can you explain the process of how the 6 layer board
with blind vias is made. Simple example that I know is wrong but is
it 3 2layer copper boards that get sandwiched together with prepreg in
between the 2nd and 3rd layer and the 4th and 5th layer? I know this
isn't the way so what is the process?

Thanks for the help.