Want to stress how extreme cleanliness have to be. Free halogen ions from the air are enough to mess it up.
That's why early fabs had very unusual placement requirements: not close to chicken farms, agriculture, water, or sewage treatment plants.
Intel famously got seasonal yield losses which they traced to agricultural activities, and seasonal chicken coup cleaning.
Re:Second IC
by pottertheotter on Saturday August 14, 2021 @02:54AM
(#28178656)
Are they able to clean the air well enough now that it’s not an issue?
Re:Second IC
by eurasiantiger on Saturday August 14, 2021 @05:11AM
(#28179258)
It’s not really feasible to separate noble gases out of the atmosphere in a building HVAC system.
Couldn't you just use positive pressure of O2 and nitrogen? Push all other gasses out? Would cost a lot but it is doable.
More recent tools do work that way. The whole "tool line" is flushed with process atmosphere.
Probably the buildings are so big nowadays that it's geometrically impossible to have farms nearby the actual plant.
How much m^3 do you need to grow these structures? Couldn't it be done in a very confined space?
This is how it's done now. Tool lines are flushed with chemically regenerated atmosphere (basically getting LOX + LN2 bottles from air liquide, and mixing them,) or argon, or nitrogen only.
Older, and cheaper fabs still rely on natural atmosphere, and other, less sure tricks to keep halogens out.
Growing the MOS gate oxide without extreme cleanness has no chance of succeeding.
The difficulty of this process has caused a delay of many decades between the time when the MOS transistor was first imagined (in 1928 by Julius Edgar Lilienfeld, then also in 1935 by Oskar Heil) and the time when working MOS transistors were made for the first time, around 1960.