Here is the list of processes and materials needed for the 16 Mbit DRAM (an about 1999) in a graphic way. | ||
| |||
Note that any material that comes in contact with the wafer or with materials that will come into contact with the wafer, is an electronic material - utmost care has to be taken in selecting the right stuff! | |||
Wafer holders or tweezer, e.g., can totally ruin a wafer by leaving minute amounts (far below the detection limit) of heavy metals (most notably Fe) on the wafer if they are unsuitable (Never, really never, touch the wafer with a metal tweezer!). | |||
Gas pipes may corrode internally if made from the wrong metal and thus contaminate the gas flowing through it with traces of impurities - your factory then will only produce garbage. | |||
Note also that some of the most dangerous inorganic chemical are used! | |||
HF (hydrofluoric acid) will cause heavy tissue and especially bone damage already by its vapors - you do not even have to touch it to get severly damaged. | |||
PH3 (phosphine) and AsH3 (arsine) are among the most toxic gases known to mankind; minute amounts are deadly (PH3, in fact, was used as a poison gas in world war I). | |||
To continue, use the link | |||
6.1.1 Materials and Processes for Silicon Technology
© H. Föll (Electronic Materials - Script)