Processes and Materials I

Here is the list of processes and materials needed for the 16 Mbit DRAM (an about 1999) in a graphic way.

Materials 1
 
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
 

To index To index as PDF

go to 5.2.1 Process Integration

go to 6.1.1 Materials and Processes for Silicon Technology

go to 6.3.2 Oxide CVD

go to Processes and Materials II

© H. Föll (Electronic Materials - Script)