Plasma Technology  


plasma ALD:
Sputtered Auger analysis showing C < 2 %

metal precursor: TEMAH

non metal precursor: O radicals and O2

dose control by fast pulse ALD valve

deposition temperature: 200° - 290° C

cycle time < 9 sec, 1.1 A/ cycle (saturated dose)
for 200 mm wafer (shorter for smaller substrates)

7 A/ min, > 45 nm/ hr (for 200 mm wafer)
(faster for smaller substrates)



ALD schematic
valve between remote ICP source
and chamber,
spectroscopic ellipsometry optional

 

thickness uniformity over 200 mm ± 1.3 %


20 nm HfO2 grown on a 40 µm
deep trench etch with
aspect ratio of 25:1

bottom sidewall
(roughness caused by the
Bosch etch process)
with 20 nm HfO2

trench bottom
with 20 nm HfO2

 

HfO2 ALD (radical assisted by remote plasma)


TEMAH molecule
tetrakis ethylmethylamino hafnium
TEMAH is heated to 70° C and used in
"bubbling mode".

 

stochiometry vs table temperature
Below 290° C (260° C wafer temp)
the H content starts to increase
significantly.


OpAL

 


Flex AL

 

Why remote plasma ALD ?

A "remote plasma" makes sure, the substrates
are NOT in contact with the plasma !

The remote plasma just cracks molecules,
so that very reactive species can be used
for the growth process.

Such reactive species often enable a very
efficient plasma preclean/ conditioning of the
substrates, lead to cleaner films and lower
the deposition temperature.

In Oxford systems it is possible to run
ALD processes using
- the thermal only method
- ozone assisted processes
- remote plasma assisted processes
together without any hardware change.
Multiple step processes using all technologies
can be chosen from the software.


H content vs plasma time

H content vs table temperature

 

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