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per minute,is the rateat whicha
as angstroms
coatingrafe,usuallyexpressed
rateincreases,
and
material,Whenthe sputtering
specimenis coveredby sputtered
of
souring
will
more
atoms
be
there
since
rateincreases,
thenthe sputter-coating
materialfloatingaround.
Manydifferentgasescanbe usedfor sputtering.Argonis typicallyusedbecauseit
price.Nitrogenis usedless
rateandhasa reasonable
promotesa highersputtering
rate.
and
thus
a lowersputter-coating
produces
rate
sputtering
a
lower
it
oftenbecause
can
Hummers
argon.
Anatech
Nitrogengas producesa sputter
' coatingratehalfthatof
onlybe usedwithinertgases.
PlateMode-toplatea specimenwith a metal
AnatechHummersproduceplasmafor platingin a chamberwitha negative-charged
stage(onwhichthe specimensits)at the
sourceat the top anda positive-charged
by a vacuumpump,andthe
bottom.DuringPlateMode,the chamberis evacuated
valve.
leak
The plasmaformswhena high
gas
adjustable
through
an
operating enters
towardthe source
voltageis appliedbetweenthe sourceand stage. lonsaccelerate
highervoltagewillproduce
to thevoltageapplied.ln general,
withenergy;proportional
the sputterrateandthe current.
moreions,whichincreases
Etch Mode-toremovematerialfrom a specimen
ln EtchMode,the polarityof the stageandtargetare reversed.DuringEtchMode,ions
surface(similarto metalatomsbeing
willdislodgematerialfromthe specimen's
dislodged
fromthe sputtersourceduringPlateMode).Materialis etchedfromthe
rateachievedin PlateMode.
slowerthanthe sputtering
specimensubstantially
heatingof the specimen.
Additionally,
EtchModecausesconsiderable
the sourcecan be contaminated
by
lf etchingcontinues
too long(overtwo minutes),
"back-sputtered"
fromthe specimen.To avoidcontaminatinga precious
material
metalsourceduringprolongedetching,replaceit with the aluminumetch ring.
withthe DigitalThickness
Monitor(DTM),always
Also,if yourHummeris equipped
removethe DTMcrystalbeforeusing Etch Mode. Handlethe DTMcrystal
carefully-don'tget fingerprints
on the crystalor debrisinsidethe crystalcan.
PlasmaMode-tocleana specimen
andetchingof metals,ceramics,
Plasmaprocessing
is usedforashing,cleaning
glasses,organicsandcomposite
materials.In contrastto Plateand EtchModes,which
current.The resultingplasmais
usedirectcurrent,PlasmaModeusesalternating
sufficiently
energetic
to removesmallamountsof organicor volatilecontaminants
from
of organicspecimens.
specimen
surfaces,
andfor cross-linking
An exposureof abouttwo minutesin PlasmaModebeforeplatingimprovesscanning
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