Have seen a number of literature articles indicating the standard material 
for a MCM-L is BT resin.

Question 1: Which laminate material suppliers make BT based resin laminates?

Question 2:  With the advent of multifunctionals what properties still make 
BT resin based laminates the preferred choice?.

Question 3: Do today's BT resin formulations still show the significant 
shrink previously reported?

Question 4:  Are there fabrication issues related to fine lines, feed 
through holes or lamination that make BT resin based multichip module boards 
more challenging to the fabricators and thus make them less cost effective 
when compared to other resin systems of comparable glass transition 
temperature?