Why do they wear the suit that cleanroom technicians must wear while making computer chips?

Answer 1

Computer chips are made up of silicon. Silicon can be converted into p type or n type using the process of doping. Doping is a process of adding impurity. it means that by added impurity, silicon changes its characteristics. In order to avoid undesired impurities, those people wear that protective suit.

Humans really have almost no impurities on their bodies that would change the characteristics of silicon or any other semiconductor. The contamination of concern here that these suits prevent is shed hairs and dead skin cells; either of which is much larger in size than several hundred transistors in a modern IC chip.

• If even one dead skin cell fell on a wafer during handling one or more chips on that wafer would be missing entirely that many transistors or the metal interconnects between all those transistors or instead all those transistors would be shorted together by one massive metal interconnect or instead various other faults would cover the area where that cell fell; depending on the process step the wafer was in.
• A hair is even worse than a skin cell as it has length and will therefor damage dozens to thousands of chips on the wafer depending on how it lands.