The above is a term I'm perhaps the last to learn. From an interesting article about a chip manufacturer that makes stacked-circuit chips:
Matrix is also trying to exploit a manufacturing advantage over other memory chip makers: its ability to use older, less expensive chip making equipment. It can do so because the vertical approach means the circuits do not have to be etched as tightly to achieve the same capacity.
"They are making great strides using lagging-edge technology," said Jim Handy, director of nonvolatile-memory research at Semico Research, a semiconductor market research firm based in Phoenix.
By using older technology, the company enjoys higher production yields, further reducing the cost of its products.