Utah-94-721002-System-Manual.pdf - 第249页
Equipment Manual lñÑçêÇ=fåëíêìãÉåíë=mä~ëã~=qÉÅÜåçäçÖó== mä~ëã~ä~Ä= f`m=NUM PKQ= dê~éÜë=çÑ=íóéáÅ~ä=çéÉê~íáåÖ=Å Ü~ê~ÅíÉêáëíáÅë= High ion flux to the wafer A figure of merit for the ICP is the ion current density at the waf…
mä~ëã~ä~Ä=f`m=NUM lñÑçêÇ=fåëíêìãÉåíë=mä~ëã~=qÉÅÜåçäçÖó== Equipment Manual=
The mä~ëã~ä~Ä f`m=NUM is an assembly which can be fitted to a mä~ëã~ä~Ä
=
póëíÉã=NMM=chamber in place of
the standard chamber lid. The assembly comprises a chamber lid on which is mounted the ICP discharge
chamber, an automatch unit and a shielding cover.
The chamber lid is secured to the process chamber by hinges which allow it to be tilted for process
chamber maintenance. The lid is water cooled by a circular cooling element. Vacuum sealing between the
lid and the process chamber is provided by an O-ring. A mounting plate attached to the lid supports the
automatch unit.
The discharge chamber comprises an insulated tube sealed at its top and bottom by O-rings. The insulated
tube is cooled at its top and bottom by cooling collars. An electrostatic shield surrounds the insulated
tube. A water-cooled RF induction coil, supported by two clamping assemblies, is located outside of the
insulated tube and electrostatic shield.
The top of the discharge chamber is a cover plate which incorporates an extraction cover, endpoint
detector port, process gas inlet, pressure relief valve and a circular cooling element. Air is drawn into the
space outside of the discharge chamber through a cooling grid.
The ICP 180 cover incorporates an interlock actuator (see Fig 2) which, when the cover is fitted, actuates a
micro-switch located under the AMU. When the micro-switch is actuated, the contactor which supplies the
source's RF Generator, is enabled. When the cover is not fitted, the RF Generator's supply is disabled.
PKP= pçìêÅÉ=ëéÉÅáÑáÅ~íáçå=
Description:
Inductively coupled plasma source for use with the mä~ëã~ä~Ä
=
póëíÉã=NMM=.
RF: Minimum generator capacity 1200W
Maximum RF power handling 3000W
Frequency: 13.56MHz.
Ion current density:
>1mA/cm
-2
at normal substrate position in the mä~ëã~ä~Ä
=
póëíÉã=
NMM, using Argon at 1 Pa.
Pressure range: 0.5Pa to10Pa (3 to 70 mTorr). (Argon) Operation to 1mTorr is
possible using >2KW RF.
Vacuum: All joints < 5 x 10
-8
mbar litre/sec leak rate on Helium leak test.
ICP 180 Source
Issue 4: January 06 Page 8 of 26 Printed: 18-Jan-06, 8:44
Equipment Manual lñÑçêÇ=fåëíêìãÉåíë=mä~ëã~=qÉÅÜåçäçÖó== mä~ëã~ä~Ä=f`m=NUM
PKQ= dê~éÜë=çÑ=íóéáÅ~ä=çéÉê~íáåÖ=ÅÜ~ê~ÅíÉêáëíáÅë=
High ion flux to the wafer
A figure of merit for the ICP is the ion current density at the wafer, without RF applied to the wafer. This
was measured by using the wafer table as an ion collection electrode, biased to -30 V dc. A good figure to
achieve is 1 mA cm-2; much less than this means the source is not effective; much higher currents are not
useful because the sample is heated too much.
The graph (see Fig 3) shows a nearly linear increase of ion current density with ICP power. There is no sign
of saturation behaviour (unlike ECR), so higher powers could be used to get higher ion fluxes if required.
The ICP 180 can handle up to 3 kW of RF power.
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
0 200 400 600 800 1000 1200 1400 1600 1800
ICP W
Ion current density mA/cm2
2 mtorr 7 mtorr 60 mtorr
Fig 3: Ion current density at the wafer versus ICP power
ICP 180 Source
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mä~ëã~ä~Ä=f`m=NUM lñÑçêÇ=fåëíêìãÉåíë=mä~ëã~=qÉÅÜåçäçÖó== Equipment Manual=
Operating window
The operating window of the ICP 180 source in nitrogen is shown in Fig 4.
0
500
1000
1500
2000
2500
0 20 40 60 80 100 120
Pressure mtorr
ICP RF power W
ICP strike power W Minimum plasma power W
Fig 4: Operating window
ICP 180 Source
Issue 4: January 06 Page 10 of 26 Printed: 18-Jan-06, 8:44