# When Semiconductors Entered the Copper Age

**URL:** <https://scanalyst.fourmilab.ch/t/when-semiconductors-entered-the-copper-age/3886>\
**Category:** Context\
**Tags:** interconnect, semiconductor-manufacturing, copper\
**Created:** [20 October 2023 14:03 UTC](https://scanalyst.fourmilab.ch/t/when-semiconductors-entered-the-copper-age/3886 "2023-10-20T14:03:37Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![johnwalker](https://scanalyst.fourmilab.ch/user_avatar/scanalyst.fourmilab.ch/johnwalker/32/17415_2.png) [@johnwalker](https://scanalyst.fourmilab.ch/u/johnwalker)\
**Post date:** [20 October 2023 14:03 UTC](https://scanalyst.fourmilab.ch/t/when-semiconductors-entered-the-copper-age/3886/1 "2023-10-20T14:03:37Z")

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[![](https://scanalyst.fourmilab.ch/uploads/default/original/3X/4/6/4619d8309f643f77d1a21a925b22b37f2e476793.jpeg "TSMC's First Breakthrough: The Copper/Low-K Interconnect Transition") ](https://www.youtube.com/watch?v=XHrQ-Pmvwao)

As semiconductor device geometries shrank to achieve greater complexity, faster speed, and lower power due to the [Dennard scaling theorem](https://en.wikipedia.org/wiki/Dennard_scaling), the physical properties of materials began to limit the ability to further reduce scale. In particular, aluminium, which had been used for integrated circuit [interconnects](https://en.wikipedia.org/wiki/Interconnect_(integrated_circuits)) (intra-chip “wiring”) from their early days, had electrical resistance sufficiently high that shrinking beyond a certain point would slow the operation of a chip due to the [RC (resistance-capacitance) time constant](https://en.wikipedia.org/wiki/RC_time_constant) of the interconnect. This was most unfortunate, since aluminium is an almost ideal material in many ways: inexpensive, easy to deposit on chips by various methods, and well-behaved in conjunction with silicon substrates. But unless something that performed better electrically was found, chip performance would hit a hard wall around the year 2000. Copper had conductivity almost 60% better than aluminium, but the difficulties in integrating it into the semiconductor fabrication process were formidable: the techniques that worked so well with aluminium couldn’t handle copper and, once applied to a chip, copper would tend to migrate into silicon structures, destroying devices and creating short circuits. When, in the late 1990s, IBM reported success in fabricating integrated circuits with [copper interconnects](https://en.wikipedia.org/wiki/Copper_interconnects), rival companies scarcely believed it, since the difficulties were so formidable, but then had to scramble to catch up. It was in this process that [Taiwan Semiconductor Manufacturing Company](https://en.wikipedia.org/wiki/TSMC) (TSMC) began to pull ahead and become the world leader in semiconductor fabrication it is today.