The simplest way to create 3-D chips is to fabricate the bottom chip as usual, cover it with oxide, then bond it to a similarly oxide clad giant-transistor donar chip, which can then be etched into individual transistors.
According to Or-Bach, NuPGA's 3-D IC fabrication techniques can be used to stack memory on top of a processor, to stack bit-wide memory chips into byte-wide configurations or just to shrink the die of existing designs by optimizing chip area versus height. Any number of chip layers can be composed, according to Or-Bach, enabling general-purpose monolithic 3-D to reduce chip areas by as much as three times over conventional 2-D.
Full Text: http://bit.ly/NextGenLog-g3rQ
