Chemistry Reference
In-Depth Information
A cleaned silicon wafer is characterized as (1) particle free, (2) without organic
contaminants, (3) minimal metallic contamination, (4) free of native oxide, and (5)
minimal surface roughness.
99,254
It has a surface concentration of contaminants such as
Fe, Cu, and Ni of less than and a microroughness of about 0.2nm.
488
As-
received wafer typically has several thousand particles, a roughness of about 0.2 nm,
and metal concentrations of about
for Fe, Cu, and Zn as shown in
131,488,493
Fig. 7.59.
The degree of cleanness is constantly improved as cleaning technol-
ogy continues to progress. As a result, the surface metal concentration has been reduced
