“In terms of circuitry, three-dimensional chips are commonly used. [By 2009.]”

Ray KurzweilThought Leader

Inventor, futurist and author of The Age of Spiritual Machines

Mainstream logic and memory in 2009 were planar; 3D-stacked devices (3D NAND, HBM, TSV logic stacking) only reached volume production years later. Kurzweil claimed vindication via 'vertical stacking', but IEEE Spectrum judged that it was 'simply wrong to insist that they already are' common.