Transcript CMP Pressure Distribution Study Group

CMP Pressure Distribution Study
Group
Final Project Update
By
Dave Bullen
Alia Koch
Alicia Scarfo
7/30/1999
Overview
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Previous work
Photos: The Jumbo 1000 in action
Data collection software redesign
Final static and dynamic pressure data
Numerical work on pad deformation
Previous Work
• Manometer Testing
– Response was to slow
– Could not measure a wide enough range
• Pressure Gage Testing
– Adequate response time
– Still could not read a wide enough range
– Could not be used with a rotating wafer
The Jumbo 1000 in Action
The Jumbo 1000 in Action
The Jumbo 1000 in Action
Data Acquisition
• LabVIEW helped because:
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Real Time Data
Very Accurate Data from Transducer
Easier to Read Data
Other Calculations made in Real Time
The Program
• We were able to control:
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Scan Rate
Scans per Channel
Total Scan Time
Total Number of Scans
Our Front Panel
Wafer Static Pressures
Pressure (psia)
Pressure vs. Position: All Taps, Static, Transducer
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Tap 6
Tap 4
Tap 5
Tap 1
Downforce
Tap 3
Tap 2
Atmospheric
Run details:
Date: 7/27/99-7/28/99
Wafer: REU-1, Static
Pad Speed: 120 RPM
Conditioning: Yes - 8 oscillations per minute
Fluid: Water with Sodium Hydroxide - pH:
11.27 - 11.30
Applied Pressure: 3 psi
Flow separation: None observed
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90
120
150
180
Position (Degrees)
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270
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330
Wafer Static Pressures
• Pressure distribution is divided into two
high pressure regions and two low pressure
regions
• There is a wide variation in the pressures
from point to point
• There is a vague increasing trend from rim
to center
Wafer Dynamic Pressures
Pressure vs. Position, All Taps, Dynamic Averages
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Note: Tap locations are unknown. This plot is assembled so that all peaks line up. This may not actually be
the case.
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Pressure (psia)
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Tap 6
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Tap 5
Tap 4
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Tap 3
Tap 2
Tap 1
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Position
Wafer Dynamic Pressures
• Pressure distribution structure is similar to
the static structure
• Less variation from point to point
• There is a strong increasing trend from rim
to center
Accomplished Numerical Goals
• Wrote structural program
– modeled pad changes using finite element
methods
– wrote program in Fortran 77 compatible with
current Fidap fluid finite element program
Update
• Program now compiles!
• Future changes to structural FEM program
– program would benefit from new mesh
generator
– observe effect of pad deformation on pressure
distribution under the wafer
• Other options
– try to incorporate strain program supplied by
Professor Perlman
Project Accomplishments
• Determined the pressure distribution under
a static and dynamic wafer via three
methods
• Created a system that can monitor film
pressure under a rotating wafer
• Used numerical methods to advance the
understanding of the pad deformation
phenomenon
Future Pressure Detector Work
• Manufacturer the rotating platform and
glass wafer as specified.
• Add a position signal to the data stream.
• Upgrade the sliding contact system to
transmit several channels.
• Redesign transducer/air purge system to
further reduce the response time.
Thanks
Dewi Bramono
Dr. Jonathan Coppeta
Dr. Livia Racz
James Hoffman
Joe Lu
The whole TAMPL gang