# 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.

| 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).
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With frame

6.2.2 Oxide CVD

Processes and Materials II

© H. Föll (Semiconductor Technology - Script)