I work as technician in a Singapore semiconductor factory. Here I share my working life as technician.
A belljar is made of quartz, and its function is to etch away the oxide layer of the wafers, before proceed to next step- metal deposition.
But one common problem with belljar is due to man made mistake- that is running with wrong wafers and get etched away into Belljar, so the belljar is contaminated with metal coating.
Using multimeter ad can see the metal coating causing conductivity. Belljar need to dismantled and send out for cleaning.
Below photo can see heavily coated with copper. become conductive.
Another issue with it is over use of belljar, or stress in weak point , the joint area. Below photo is broke at welding point and causing long machine long down time as need to clean the debris.
As belljar made of quartz , dimension is very critical. And also costly to make one.
Stay tune for more Singapore Semiconductor Technology !
