Chapter 12 Physical Vapor Deposition (PVD)

Evaporation Process:
*Chamber under high vacuum (low pressure and long mfp)
*metal pieces placed in crucible (charge) and heated to T m
*substrates placed above the crucible, and
*metal deposits on the substrates.
Not shown in picture is a shutter that would be
opened when the evaporation rate reaches a certain
rate indicating pure metal deposition.
View factor associated with deposition (like RTP);
deposition rate depends on location of wafer in
chamber (above crucible will have ↑ dep rate).
For better uniformity and step coverage, planetary
sample holders are rotated during deposition and
samples are heated.
Deposition rate monitored with quartz crystal
(oscillates at a resonance frequency that shifts when
additional mass is deposited on the crystal).
Figure 12.1 A simple diffusion-pumped
evaporator showing vacuum plumbing and
the location of the charge-containing
crucible and the wafers.