Editing Integrated circuit (section)

===Large-scale integration (LSI) {{Anchor|LSI}}===
Further development, driven by the same MOSFET scaling technology and economic factors, led to "large-scale integration" (LSI) by the mid-1970s, with tens of thousands of transistors per chip.<ref name="Hittinger">{{cite journal |last1=Hittinger |first1=William C. |title=Metal-Oxide-Semiconductor Technology |journal=Scientific American |date=1973 |volume=229 |issue=2 |pages=48–59 |jstor=24923169 |doi=10.1038/scientificamerican0873-48 |bibcode=1973SciAm.229b..48H }}</ref>

The masks used to process and manufacture SSI, MSI and early LSI and VLSI devices (such as the microprocessors of the early 1970s) were mostly created by hand, often using [[Rubylith]]-tape or similar.<ref>{{cite web |url=https://www.cnet.com/news/intels-accidental-revolution/ |title=Intel's Accidental Revolution |website=CNET|author=Kanellos, Michael |date=January 16, 2002}}</ref> For large or complex ICs (such as [[Computer memory|memories]] or [[Processor (computing)|processors]]), this was often done by specially hired professionals in charge of circuit layout, placed under the supervision of a team of engineers, who would also, along with the circuit designers, inspect and [[Functional verification|verify the correctness and completeness]] of each mask.

Integrated circuits such as 1K-bit RAMs, calculator chips, and the first microprocessors, that began to be manufactured in moderate quantities in the early 1970s, had under 4,000 transistors. True LSI circuits, approaching 10,000 transistors, began to be produced around 1974, for computer main memories and second-generation microprocessors.