Transcript RGA Filament Control Schemes

Automation of
RGAs and Sensors
for FDC of PVD
Metal Thin Film
Processing
Arif Choudhury1, Eric McCormick1, Guy Takayesu1,
Keith Han3, Alex Lee3, Young Hwan Lee3, Justin
Wong2, and John Yoo2
1TriQuint
Semiconductor Corporation, 500 W Renner Rd, Richardson, Texas, USA 75080
America, 4633 Old Ironsides Dr, Suite 300, Santa Clara, CA 95054
3BISTel Inc. 2F, Jeongpung Bldg, 1341-3 Seocho-dong, Seocho-gu, Seoul, Korea 137-070
2BISTel
© 2013 TriQuint Semiconductor, Inc.
Content
• Introduction
– RGA Usage In PVD Process
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Applications of RGA in Manufacturing
Architecture of FDC and Sensors
RGA Filament Control Schemes
Examples of FDC with RGA
Future Work
Conclusion
© 2013 TriQuint Semiconductor, Inc.
Introduction of RGA and RGA Usage in PVD
• The RGA is commonly used to identify atomic
and molecular species in a high vacuum
environment.
• In the PVD process the RGA is commonly
used to monitor contamination before and
during the process.
– Screens the incoming substrate for resist residue
– Monitoring process gases
• The RGA is very sensitive, it can detect low
pressure contaminants in 10-14 Torr
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Pressure Range of PVD Process
• Various Vacuum Mediums*
*http://www.eng.tau.ac.il/~yosish/courses/vlsi.html
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RGA Advantage
• The RGA is an ideal tool for monitoring of PVD
process because it can detect subtle changes in
the chamber condition, i.e. contamination
• The mean free path increases at high vacuum so
the probability of detecting a contaminant goes
up.
• Can report the probable species of molecule
present in the PVD chamber.
• Possible real time detection of contaminants or
chamber leaks.
• Not reliant on metrology feedback.
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Applications of RGA in Manufacturing
• Baseline Spectrum
– Spectrum scan of a known good chamber or condition
• Spectrum Analysis (Troubleshooting)
– Analyzing the species that exist inside a chamber that is
having some unknown issue
• He Leak Checking
– Standard practice after a PVD target change
• Stand Alone Process Analysis
– The RGA manufacturers offer stand alone packages for
near real time analysis of spectrum as the tool is running.
– Typically not integrated into the house FDC system.
– High cost for the software.
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Benefits of Integrating RGA with FDC
 Having one system that can connect to
multiple components and interdict in the
event of an incident saves the expense of
having multiple FDC systems for each
component
 Adding RGAs from different
manufacturers that are not supported by
the tool OEMs.
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Architecture of FDC and Sensors
FDC
Y-TAP
Chamber Processing Status
RGA
Application
RF
Application
RGA Control
Libraries
RF Data
Collection
Library
Pump
Application
Pump Data
Collection
Library
• Wafer Processing Status of
Each Chamber
•Trace Data
RF
Pump
PVD
Controller
PM1
PM2
PM6
PM5
PM3
PM4
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Pump
Component Connections
• Tool SVIDs  HSMS Ethernet
• RF Monitor  A to D device to receive
the analog signals and pass them to the
Ethernet
• Pump data  RS-232 hub to Ethernet
convertor
• Others?
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What is Gained?
• Context for sensors that are not available on
processing chambers.
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RGA Filament Control Schemes
• RGA operation constraint
– Open Ion Source mode of RGA operation
– RGA operating pressure region is limited
– Filament tripped off when P > 9.0 x 10-3Torr
• Customized RGA filament control schemes
– P < 9.0 x 10-3Torr, filament is always on
– P > 9.0 x 10-3Torr, filament on only for a short
time (10sec.) at end of wafer process,
otherwise filament is off
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Real time control with integrated sensors like the RGA
Chamber Pressure
Filament Status
(On)
•Example of RGA control
to sample at the end of a
process run.
AMU 28 (N2)
Process is complete. FDC sends
the command to ignite the RGA
filament.
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RGA contaminated bottle controlled test
• A small Ar bottle that was purposely contaminated with
1600ppm of N2 was connected to a PVD chamber as a
controlled test.
1.40E-05
Pressure
1.00E-05
8.00E-06
6.00E-06
4.00E-06
2.00E-06
0.00E+00
1
N2
Contamination
Rs
Ar36 Test
Bottle
N2 Test
Bottle
Ar36 House
Bottle
N2 House
Bottle
1.20E-05
11 21 31 41 51 61 71
Time
* The Ar36 isotope was chosen for the graph instead of Ar40 because of the
signal magnitude relative to the magnitude of N2.
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Sample
Example 1: Real Time RGA Alarm
•Ar should be present.
•O2 and H2 are baseline
signals.
•N2 peak (pulse) detected.
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Example 2: Chamber Lid Leak RGA Trace
AMU28 (N2)- Red  Chamber lid leak
Blue  Normal
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Future Work
• Implementing RGA at house Ar gas supply
– Detect problem at time close to t0
– Minimize recovery
• Adding Real-time leak test recipes for
maintenance and operators
– Post chamber recovery
– Weekly chamber integrity check
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Conclusion
• There is great value in integrating RGAs and
other sensors into an in-house FDC system.
– Sensor Control
– Real time context with existing tool parameters
– Real time detection
© 2013 TriQuint Semiconductor, Inc.
Acknowledgement
• The authors want to express their
appreciations for the valuable inputs on this
project from Romek Bobkowski and Richard
Groom, both of TriQuint Semiconductor
Corporation on PVD processing and RGA
operation respectively.
© 2013 TriQuint Semiconductor, Inc.
© 2013 TriQuint Semiconductor, Inc.